Patent Application
20190147206
The present invention relates to technology by which information is written onto a durable information recording medium and stored therein and also the information is read out from the written information recording medium and in particular relates to technology by which beam exposure and pattern processing are performed on a substrate to record information as a minute physically structured pattern and also read out the information.
Paper has been used as a medium for recording various types of information for a very long time, and many types of information are even now recorded on paper. On the other hand, with advancements in industries, films for recording image information and record disks for recording sound information have been made available. In recent years, due to wide use of computers, there have been used magnetic recording media, optical recording media, semiconductor recording media and others as media for recording digital data.
The above-described information recording media are provided with durability to such an extent that will not cause any trouble in using them, depending on individual use. It may be safe to say that information recording media, for example, printed matter of paper, film and record disks are media which are sufficiently durable when used on a time scale of several years. However, on a time scale of several decades, these information recording media will inevitably deteriorate with the lapse of time and may be unable to maintain recorded information. Further, they may be damaged not only with the lapse of time but also by water and thermal influences.
Further, magnetic recording media, optical recording media, semiconductor recording media and others for computers are provided with durability to such an extent that will not cause trouble in using general electronic devices. However, these media are not designed, with durability on a time scale of several decades taken into account and, therefore, not suitable as permanent information storage media.
On the other hand, in Patent Document 1 given below, as a method for recording information on a durable medium like quartz glass, with a recording capacity enhanced, there has been disclosed a method in which data is recorded three dimensionally at small cells within a cylindrical medium based on a difference in light transmittance, and while the medium is rotated, computer tomography technology is utilized to read out the information. Further, in Patent Document 2, there has been disclosed a method in which in order to attain the same purpose, a cylindrical recording medium is exposed to irradiation of electromagnetic waves by changing an irradiation angle to measure a difference in transmittance and read out information also by utilizing the computer tomography technology.
It is noted that a plate-like information recording medium is provided with front, back, top, bottom, left and right sides. Upon reading out recorded information, it is necessary to perform readout processing after correct confirmation of the medium as for a direction such as front, back, top, bottom, left and right sides. Thus, there has been proposed a method for providing an identification mark indicating a direction on a medium for the purpose of performing correct readout processing. For example, in Patent Document 3 given below, such technology has been disclosed that an identification mark having a recess and protrusion structure is provided at a lower right corner on the front side of a card-like information recording medium, by which even a visually impaired person is able to recognize a direction of the medium by touching it and inserting the card-like information recording medium into an information reader in a correct direction.
As described above, information recording media which is currently in general use are designed to be durable for several years to several decades. These media are, therefore, not appropriate as media for passing down information to generations on a longer time scale of several hundred to several thousand years. Physically or chemically vulnerable information recording media, for example, paper, film and record disks, are not expected to be durable for a longer period of time such as several hundred to several thousand years. Of course, information recording media for computers such as magnetic recording media, optical recording media and semiconductor recording media are not appropriate either when used as described above.
In human history, there are stone monuments as information recording media which have passed a time scale of several hundred to several thousand years. It is, however, quite difficult to perform highly integrated recording of information on a stone plate. A stone plate is not appropriate as a medium for recording large capacity information such as digital data for computers.
On the other hand, as described in the technology disclosed in the previous Patent Documents 1 and 2, there is adopted a method in which cylindrical quartz glass is used as a medium to record information therein in a three-dimensional manner, thus making it possible to realize an information recording method which can be highly integrated, with long-term durability maintained. It is, however, necessary to extract information from three-dimensionally dispersed cells in a medium when the information is read out. This requires Fourier transform processing by utilizing computer tomography technology. In other words, unless the computer tomography technology the same as that available at the time of recording the information is taken over after passage of a long-time scale of several hundred to several thousand years, it will be impossible to read out the information.
Thus, an object of the present invention is to provide an information storage process and a device thereof capable of performing highly integrated recording of information and also capable of reading the information in a universal method, with long-term durability maintained. The present invention is also to provide a process and a device for reading out original information from a medium in which the information is stored in the above-described method. Further, the present invention proposes a new process in which beam exposure and pattern processing are performed on a substrate, thus making it possible to record information which shows a method for interpreting data bits when the information is recorded as a minute physically structured pattern.
(1) The first feature of the present invention resides in an information storage device in which digital data is written onto an information recording medium and stored in it,
the information storage device, comprising:
a data input portion which inputs digital data to be stored;
a unit data creating portion in which the digital data is divided by a prescribed bit length unit to create a plurality of unit data;
a unit bit matrix creating portion in which data bits which constitute individual unit data are arranged in a two-dimensional matrix form to create a unit bit matrix;
a unit bit graphic pattern creating portion in which the unit bit matrix is converted to a geometrical pattern arranged inside a predetermined bit recording domain, thereby creating a unit bit graphic pattern;
a unit recording graphic pattern creating portion in which an alignment mark is added to the unit bit graphic pattern to create a unit recording graphic pattern;
a drawing data creating portion which creates drawing data for drawing the unit recording graphic pattern;
a beam exposure device which performs beam exposure using electron beams or laser light on a substrate which acts as an information recording medium on the basis of the drawing data; and
a patterning device which performs pattern processing on the substrate which has been exposed, thereby creating the information recording medium in which a physically structured pattern is formed according to the drawing data.
(2) The second feature of the present invention resides in the information storage device according to the first feature, wherein
the beam exposure device has a function which performs beam exposure on a substrate having an underlying layer and a resist layer which covers the underlying layer, the beam exposure being made on a surface of the resist layer, and
the patterning device includes a development processing portion in which the substrate is immersed into a developing fluid having properties that will dissolve an exposed part or a non-exposed part of the resist layer and a part of the substrate is processed into a remaining part, and an etching processing portion in which the underlying layer is etched by using the remaining part of the resist layer as a mask.
(3) The third feature of the present invention resides in the information storage device according to the second feature, wherein
the unit bit graphic pattern creating portion converts one of an individual bit “1” and an individual bit “0” which constitute the unit bit matrix to an individual bit figure composed of a closed domain,
the drawing data creating portion creates the drawing data which shows a contour line of the individual bit figure, and
the beam exposure device performs beam exposure on an interior part of the contour line of the individual bit figures.
(4) The fourth feature of the present invention resides in the information storage device according to any one of the first to the third features, wherein
the patterning device forms a physically structured pattern which has a recess and protrusion structure composed of a recess which shows one of a bit “1” and a bit “0” and a protrusion which shows the other of them.
(5) The fifth feature of the present invention resides in the information storage device according to the fourth feature, wherein
the patterning device forms a physically structured pattern having an added layer made of a light reflective material or a light absorbing material on a surface of one of a recess and a protrusion or on surfaces of both of them.
(6) The sixth feature of the present invention resides in the information storage device according to any one of the first to the third features, wherein
the patterning device forms a physically structured pattern having a network structure composed of a through hole which shows one of a bit “1” and a bit “0” and a non-hole part which shows the other of them.
(7) The seventh feature of the present invention resides in the information storage device according to any one of the first to the sixth features, wherein
the unit data creating portion divides digital data into unit data composed of (m×n) bits,
the unit bit matrix creating portion creates a unit bit matrix composed of m rows and n columns, and
the unit bit graphic pattern creating portion allows individual bits which constitute the unit bit matrix to correspond to grid points arranged in a matrix form composed of m rows and n columns, and bit figures with a predetermined shape are arranged on grid points corresponding to a bit “1” or a bit “0,” thereby creating a unit bit graphic pattern.
(8) The eighth feature of the present invention resides in the information storage device according to the seventh feature, wherein
the unit bit graphic pattern creating portion creates a unit bit graphic pattern arranged inside a rectangular bit recording domain,
the unit recording graphic pattern creating portion adds an alignment mark outside the rectangular bit recording domain, thereby creating a unit recording graphic pattern arranged inside a rectangular unit recording domain which includes the bit recording domain and the alignment mark, and
the drawing data creating portion arranges the rectangular unit recording domains in a two-dimensional matrix form, thereby creating a drawing pattern including a plurality of unit recording graphic patterns and creating drawing data for drawing the drawing pattern.
(9) The ninth feature of the present invention resides in the information storage device according to the eighth feature, wherein
the unit recording graphic pattern creating portion adds a total of two sets of alignment marks arranged outside in vicinities of two corners not at a diagonal position, of four corners, in the rectangular bit recording domain, thereby creating a unit recording graphic pattern.
(10) The tenth feature of the present invention resides in the information storage device according to the eighth feature, wherein
the unit recording graphic pattern creating portion adds a total of three sets of alignment marks arranged outside in vicinities of three corners, of four corners, in the rectangular bit recording domain, thereby creating a unit recording graphic pattern and also making difference in an arrangement mode of three sets of the alignment marks in unit recording graphic patterns which are adjacent to each other.
(11) The eleventh feature of the present invention resides in the information storage device according to the ninth or the tenth feature, wherein
the unit recording graphic pattern creating portion sets a specific unit recording domain at a reference unit recording domain and creates a unit recording graphic pattern in which a reference alignment mark different from that at other unit recording domains is used at the reference unit recording domain.
(12) The twelfth feature of the present invention resides in the information storage device according to any one of the first to the eleventh features, wherein
the data input portion, the unit data creating portion, the unit bit matrix creating portion, the unit bit graphic pattern creating portion, the unit recording graphic pattern creating portion and the drawing data creating portion are constituted by installing programs into a computer.
(13) The thirteenth feature of the present invention resides in a program which allows a computer to function as the data input portion, the unit data creating portion, the unit bit matrix creating portion, the unit bit graphic pattern creating portion, the unit recording graphic pattern creating portion and the drawing data creating portion in the information storage device according to any one of the first to the eleventh features.
(14) The fourteenth feature of the present invention resides in an information readout device which reads out digital data stored at an information recording medium by using the information storage device according to the first feature,
the information readout device, comprising:
an image photographing device which magnifies and photographs a domain to be photographed which is a part of a recording surface of the information recording medium to capture an obtained photographed image as image data;
a photographed-image housing portion which houses the photographed image;
a bit-recording-domain recognizing portion which detects an alignment mark from the photographed image housed in the photographed-image housing portion, thereby recognizing individual bit recording domains;
a unit-bit-matrix recognizing portion which recognizes a unit bit matrix on the basis of a pattern inside the bit recording domain;
a scanning controller which controls a change in domain to be photographed by the image photographing device so that a photographed image can be obtained in all bit recording domains to be readout; and
a data restoration portion which creates unit data from individual unit bit matrixes recognized by the unit-bit-matrix recognizing portion to synthesize individual unit data, thereby restoring the digital data stored.
(15) The fifteenth feature of the present invention resides in an information readout device which reads out digital data stored in an information recording medium by using the information storage device according to the eleventh feature,
the information readout device, comprising:
an image photographing device which magnifies and photographs a domain to be photographed which is a part of a recording surface of the information recording medium to capture an obtained photographed image as image data;
a photographed-image housing portion which houses the photographed image;
a bit-recording-domain recognizing portion which detects an alignment mark from the photographed image housed in the photographed-image housing portion, thereby recognizing individual bit recording domains;
a unit-bit-matrix recognizing portion which recognizes a unit bit matrix on the basis of a pattern inside the bit recording domain;
a scanning controller which controls a change in domain to be photographed by the image photographing device so that a photographed image can be obtained for all bit recording domains to be readout; and
a data restoration portion which creates unit data from individual unit bit matrixes recognized by the unit-bit-matrix recognizing portion to synthesize individual unit data, thereby restoring the digital data stored; wherein
the image photographing device has a function to photograph a domain to be photographed, a size of which is able to include at least one unit recording domain, and
the scanning controller controls the image photographing device to adjust a domain to be photographed so that a photographed image of a domain which includes a reference unit recording domain is obtained on the basis of a reference alignment mark and, thereafter, a domain to be photographed is sequentially allowed to move depending on an arrangement pitch of unit recording domains.
(16) The sixteenth feature of the present invention resides in the information readout device according to the fourteenth or the fifteenth feature, wherein
the photographed-image housing portion, the bit-recording-domain recognizing portion, the unit-bit-matrix recognizing portion, the scanning controller and the data restoration portion are constituted by installing programs into a computer.
(17) The seventeenth feature of the present invention resides in a program for allowing a computer to function as the photographed-image housing portion, the bit-recording-domain recognizing portion, the unit-bit-matrix recognizing portion, the scanning controller and the data restoration portion in the information readout device according to the fourteenth or the fifteenth feature.
(18) The eighteenth feature of the present invention resides in an information storage method by which digital data is written onto an information recording medium and stored in it,
the information storage method, comprising:
a data input step in which a computer inputs digital data to be stored;
a unit data creating step in which the computer divides the digital data into a prescribed bit length unit to create a plurality of unit data;
a unit bit matrix creating step in which the computer arranges data bits which constitute individual unit data in a two-dimensional matrix form to create a unit bit matrix;
a unit bit graphic pattern creating step in which the computer converts the unit bit matrix to a geometrical pattern arranged inside a predetermined bit recording domain, thereby creating a unit bit graphic pattern;
a unit recording graphic pattern creating step in which the computer adds an alignment mark to the unit bit graphic pattern, thereby creating a unit recording graphic pattern;
a drawing data creating step in which the computer creates drawing data for drawing the unit recording graphic pattern;
a beam exposure step in which beam exposure is performed by using electron beams or laser light on a substrate which acts as the information recording medium on the basis of the drawing data; and
a patterning step in which pattern processing is performed on the substrate which has been exposed, thereby creating the information recording medium in which a physically structured pattern is formed according to the drawing data.
(19) The nineteenth feature of the present invention resides in an information readout method by which digital data stored in an information recording medium by using the information storage method according to the eighteenth feature, is read out,
the information readout method, comprising:
an image photographing step in which a domain to be photographed which is a part of a recording surface of the information recording medium is magnified and photographed by using an image photographing device and an obtained photographed image is captured as image data;
a photographed-image housing step in which a computer houses the photographed image;
a bit-recording-domain recognizing step in which the computer detects an alignment mark from the photographed image housed by the photographed image housing step, thereby recognizing individual bit recording domains;
a unit-bit-matrix recognizing step in which the computer recognizes a unit bit matrix on the basis of a pattern inside the bit recording domain; and
a data restoration step in which the computer creates unit data from individual unit bit matrixes recognized in the unit-bit-matrix recognizing step to synthesize individual unit data, thereby restoring digital data stored, wherein
in the image photographing step, the computer controls a change of a domain to be photographed by the image photographing device so that a photographed image can be obtained in all bit recording domains to be read out.
(20) The twentieth feature of the present invention resides in an information storage device in which digital data is written onto an information recording medium and stored in it,
the information storage device, comprising:
a data input portion which inputs digital data to be stored;
a main information pattern creating portion which creates a main information pattern that shows information of individual data bits which constitute the digital data;
a minor information pattern creating portion which creates a minor information pattern that shows a method for interpreting data bits shown by the main information pattern;
a drawing data creating portion which creates drawing data for drawing the main information pattern and the minor information pattern;
a beam exposure device which performs beam exposure using electron beams or laser light on a substrate which acts as an information recording medium on the basis of the drawing data; and
a patterning device which performs pattern processing on the substrate which has been exposed, thereby creating an information recording medium in which a physically structured pattern is formed according to the drawing data, wherein
the main information pattern is a pattern which is constituted with a first attribute main domain and a second attribute main domain and in which binary information of individual data bits is expressed by a difference in whether a predetermined point corresponding to each of individual data bits is present inside the first attribute main domain or inside the second attribute main domain,
the minor information pattern is a pattern which is provided with a first identification mark having one or a plurality of closed domains for presenting first information which is composed of letters, numbers, symbols, figures or a part of them or a combination of them and a second identification mark having one or a plurality of closed domains for presenting second information which is composed of letters, numbers, symbols, figures or a part of them or a combination of them,
a band-like first attribute minor domain and a band-like second attribute minor domain extending in a direction parallel to a predetermined arrangement axis are alternately arranged in a direction orthogonal to the arrangement axis inside a closed domain which constitutes the first identification mark, a band-like first attribute minor domain and a band-like second attribute minor domain extending in a direction parallel to the arrangement axis are alternately arranged in a direction orthogonal to the arrangement axis inside a closed domain which constitutes the second identification mark and also at the closed domain which constitutes the first identification mark, a width of the first attribute minor domain is set to be greater than a width of the second attribute minor domain, at the closed domain which constitutes the second identification mark, a width of the second attribute minor domain is set to be greater than a width of the first attribute minor domain, and
the drawing data creating portion creates drawing data so that exposure is performed on the first attribute main domain and the first attribute minor domain and no exposure is performed either on the second attribute main domain or the second attribute minor domain, or the drawing data creating portion creates drawing data so that exposure is performed on the second attribute main domain and the second attribute minor domain and no exposure is performed either on the first attribute main domain or the first attribute minor domain, and also the width of the first attribute minor domain and that of the second attribute minor domain are dimensionally set so as to constitute a diffraction grating for visible light.
(21) The twenty-first feature of the present invention resides in the information storage device according to the twentieth feature, wherein
the minor information pattern creating portion creates a minor information pattern so that the first identification mark and the second identification mark formed on an information recording media are made available in a macroscopically observable size.
(22) The twenty-second feature of the present invention resides in the information storage device according to the twentieth or the twenty-first feature, wherein
the minor information pattern creating portion sets a closed domain which constitutes the first identification mark so that the width of the first attribute minor domain is at least 5 times greater than the width of the second attribute minor domain and also sets a closed domain which constitutes the second identification mark so that the width of the second attribute minor domain is at least 5 times greater than the width of the first attribute minor domain.
(23) The twenty-third feature of the present invention resides in the information storage device according to any one of the twentieth to the twenty-second features, wherein
the minor information pattern creating portion sets the width of the first attribute minor domain inside a closed domain which constitutes the first identification mark so as to be equal to the width of the second attribute minor domain inside a closed domain which constitutes the second identification mark and also sets the width of the second attribute minor domain inside a closed domain which constitutes the first identification mark so as to be equal to the width of the first attribute minor domain inside a closed domain which constitutes the second identification mark.
(24) The twenty-fourth feature of the present invention resides in the information storage device according to any one of the twentieth to the twenty-third features, wherein
the minor information pattern creating portion creates a minor information pattern in which a first identification mark and a second identification mark are arranged adjacently to each other.
(25) The twenty-fifth feature of the present invention resides in the information storage device according to any one of the twentieth to the twenty-third features, wherein
the minor information pattern creating portion creates a minor information pattern in which a closed domain which constitutes a first identification mark is in contact with a closed domain which constitutes a second identification mark.
(26) The twenty-sixth feature of the present invention resides in the information storage device according to any one of the twentieth to the twenty-third features, wherein
the minor information pattern creating portion creates a minor information pattern in which a second identification mark is embedded into a first identification mark or the minor information pattern in which the first identification mark is embedded into the second identification mark.
(27) The twenty-seventh feature of the present invention resides in the information storage device according to any one of the twentieth to the twenty-third features, wherein
the minor information pattern creating portion creates a minor information pattern which has an auxiliary common identification mark in addition to a first identification mark and second identification marks,
the auxiliary common identification mark is an identification mark which has one or a plurality of closed domains for presenting an auxiliary common information composed of letters, numbers, symbols and figures or a part of them or a combination of them,
a band-like first attribute minor domain and a band-like second attribute minor domain extending in a direction parallel to an arrangement axis are alternately arranged in a direction orthogonal to the arrangement axis inside a closed domain which constitutes the auxiliary common identification mark, and also a difference between the width of the first attribute minor domain and the width of the second attribute minor domain in the auxiliary common identification mark is set so as to be smaller than a difference between the width of the first attribute minor domain and the width of the second attribute minor domain in the first identification mark and the second identification mark.
(28) The twenty-eighth feature of the present invention resides in the information storage device according to the twenty-seventh feature, wherein
the width of the first attribute minor domain is set equal to the width of the second attribute minor domain in the auxiliary common identification mark.
(29) The twenty-ninth feature of the present invention resides in the information storage device according to the twenty-seventh or the twenty-eighth feature, wherein
an emblem which shows a first method for interpreting data bits shown by the main information pattern is constituted by a combination of the first identification mark and the auxiliary common identification mark and an emblem which shows a second method for interpreting data bits shown by the main information pattern is constituted by a combination of the second identification marks and the auxiliary common identification mark.
(30) The thirtieth feature of the present invention resides in the information storage device according to the twenty-ninth feature, wherein
three rectangles of a left-side rectangle, a central rectangle and a right-side rectangle are arranged adjacently in a horizontal direction so as to be respectively on a left side, at a center and on a right side, and a lower rectangle is arranged below so as to be commonly adjacent to the three rectangles,
a first identification mark is constituted by the central rectangle, a second identification mark is constituted by the left-side rectangle and the right-side rectangle, an auxiliary common identification mark is constituted by the lower rectangle, thereby constituting a first emblem which shows a symbol “protrusion” and a second emblem which shows a symbol “recess.”
(31) The thirty-first feature of the present invention resides in the information storage device according to any one of the twentieth to the thirtieth features, wherein
the beam exposure device has a function which performs beam exposure on a substrate having an underlying layer and a resist layer which covers the underlying layer, the beam exposure being made on a surface of the resist layer,
the patterning device includes a development processing portion in which the substrate is immersed into a developing fluid having the properties that will dissolve an exposed part or a non-exposed part of the resist layer and a part of the substrate is processed into a remaining part, and an etching processing portion in which the underlying layer is etched by using the remaining part of the resist layer as a mask.
(32) The thirty-second feature of the present invention resides in the information storage device according to the thirty-first feature, wherein
the main information pattern creating portion converts one of an individual bit “1” and an individual bit “0” to an individual bit figure composed of a closed domain, thereby creating a main information pattern in which a domain inside the bit figure is performed as the first attribute main domain and a domain outside thereof is performed as the second attribute main domain, and
the drawing data creating portion creates drawing data by which exposure is performed on the first attribute main domain and the first attribute minor domain and no exposure is performed either on the second attribute main domain or the second attribute minor domain.
(33) The thirty-third feature of the present invention resides in the information storage device according to any one of the twentieth to the thirty-second features, wherein
the patterning device forms a physical structure body which has a recess and protrusion structure composed of a recess which shows one of the first attribute domains and the second attribute domains and a protrusion which shows the other of them.
(34) The thirty-fourth feature of the present invention resides in the information storage device according to the thirty-third feature, wherein
the patterning device forms a physical structure body which has an added layer made of a light-reflective material on a surface of the protrusion.
(35) The thirty-fifth feature of the present invention resides in the information storage device according to the thirty-third feature, wherein
the patterning device performs pattern processing on a substrate made of a translucent material, thereby forming a recess and protrusion structure on an upper face of the substrate and forming a physical structure body which has an added layer made of a light-shielding material on a lower face of the substrate.
(36) The thirty-sixth feature of the present invention resides in the information storage device according to the thirty-third feature, wherein
the patterning device performs pattern processing on the substrate made of a translucent material, thereby forming a recess and protrusion structure and forming a physical structure body which has an added layer made of a light-shielding material on a surface of the protrusion.
(37) The thirty-seventh feature of the present invention resides in the information storage device according to any one of the twentieth to the thirty-second features, wherein
the patterning device forms a physical structure body which has a network structure composed of a through hole showing one of the first attribute domains and the second attribute domains and a non-hole part which shows the other of them.
(38) The thirty-eighth feature of the present invention resides in the information storage device according to the thirty-seventh feature, wherein
the patterning device forms a physical structure body which has an added layer made of a light-reflective material on one side of the non-hole part.
(39) The thirty-ninth feature of the present invention resides in the information storage device according to the thirty-seventh feature, wherein
the patterning device performs pattern processing on a substrate made of a translucent material, thereby forming a network structure and forming a physical structure body which has an added layer made of a light-shielding material on one side of the non-hole part.
(40) The fortieth feature of the present invention resides in the information storage device according to any one of the twentieth to the thirtieth features, wherein
the data input portion, the main information pattern creating portion, the minor information pattern creating portion and the drawing data creating portion are constituted by installing programs into a computer.
(41) The forty-first feature of the present invention resides in a program which allows a computer to function as the data input portion, the main information pattern creating portion, the minor information pattern creating portion and the drawing data creating portion in the information storage device according to any one of the twentieth to the thirtieth features.
(42) The forty-second feature of the present invention resides in an information storage method by which digital data is written onto an information recording medium and stored in it,
the information storage method, comprising:
a data input step in which a computer inputs digital data to be stored;
a main information pattern creating step in which the computer creates a main information pattern which shows information of individual data bits which constitute the digital data;
a minor information pattern creating step in which the computer creates a minor information pattern which shows a method for interpreting data bits shown by the main information pattern;
a drawing data creating step in which the computer creates drawing data for drawing the main information pattern and the minor information pattern;
a beam exposure step in which beam exposure is performed by using electron beams or laser light on a substrate which acts as an information recording medium on the basis of the drawing data; and
a patterning step in which pattern processing is performed on the substrate which has been exposed, thereby creating the information recording medium in which a physically structured pattern is formed according to the drawing data; wherein
the main information pattern is a pattern which is constituted with a first attribute main domain and a second attribute main domain and in which binary information of individual data bits is expressed by a difference in whether a predetermined point which corresponds to each of individual data bits is present inside the first attribute main domain or inside the second attribute main domain,
the minor information pattern is a pattern which is provided with a first identification mark having one or a plurality of closed domains for presenting first information composed of letters, numbers, symbols, and figures or a part of them or a combination of them and a second identification mark having one or a plurality of closed domains for presenting second information composed of letters, numbers, symbols and figures or a part of them or a combination of them,
a band-like first attribute minor domain and a band-like second attribute minor domain extending in a direction parallel to a predetermined arrangement axis are alternately arranged in a direction orthogonal to the arrangement axis inside a closed domain which constitutes the first identification mark, a band-like first attribute minor domain and a band-like second attribute minor domain extending in a direction parallel to the arrangement axis are alternately arranged in a direction orthogonal to the arrangement axis inside a closed domain which constitutes the second identification mark and also at the closed domain which constitutes the first identification mark, a width of the first attribute minor domain is set so as to be greater than a width of the second attribute minor domain, and at the closed domain which constitutes the second identification mark, a width of the second attribute minor domain is set so as to be greater than a width of the first attribute minor domain, and
in the drawing data creating step, drawing data is created so that exposure is performed on the first attribute main domain and the first attribute minor domain and no exposure is performed either on the second attribute main domain or the second attribute minor domain, or drawing data is created so that exposure is performed on the second attribute main domain and the second attribute minor domain and no exposure is performed either on the first attribute main domain or the first attribute minor domain, and also the width of the first attribute minor domain and that of the second attribute minor domain are dimensionally set so as to constitute a diffraction grating for visible light.
According to a basic embodiment of the present invention, digital data to be stored is divided into a plurality of unit data, changed into a form of unit bit matrix and, thereafter, converted to a geometrical graphic pattern. This graphic pattern is transferred onto a substrate by beam exposure using electron beams or laser light and recorded as a minute physically structured pattern performed by pattern processing. Therefore, information can be recorded in a highly integrated manner, with long-term durability maintained. Further, the graphic pattern in itself which has been transferred onto the substrate is a two-dimensional pattern, thus making it possible to read out the information in a universal method.
Further, in an embodiment which records an identification mark of the present invention, there is recorded a unique identification mark for showing a method for interpreting data bits. The identification mark is adopted, by which information on individual data bits which constitute digital data to be stored is recorded as a main information pattern on a medium. Further, information showing a method for interpreting data bits indicated by the main information pattern is recorded as a minor information pattern on the same medium. Here, each of the information patterns is constituted with a first attribute domain and a second attribute domain. The information is recorded on a substrate so that, for example, one attribute domain is given as a protrusion and the other attribute domain is given as a recess. Further, the minor information pattern includes a pair of identification marks, and there is formed a diffraction grating in which a band-like first attribute domain and a band-like second attribute domain are alternately arranged in the interior of each of the identification marks.
Moreover, a dimensional relationship between the width of the band-like first attribute domain and the width of the band-like second attribute domain each formed in the interior of the identification mark has a reverse relationship with regard to the pair of identification marks. Resultantly, regardless of the method for beam exposure and that for pattern processing adopted at the time of recording information, brightness and darkness between the pair of identification marks can be compared to recognize a correct method for interpreting data bits recorded as the main information pattern.
As described above, a method for utilizing the unique identification mark according to the present invention is adopted, by which beam exposure and pattern processing are performed on a substrate, thus making it possible to record also information which shows a method for interpreting data bits when the information is recorded as a minute physically structured pattern.
Here, the storage processing computer 100 executes processing for creating drawing data E on the basis of digital data D to be stored. The beam exposure device 200 is a device for executing beam exposure on a substrate S, which is an information recording medium, by using electron beams or laser light on the basis of this drawing data E, and a drawing pattern is formed on the substrate S by the beam exposure. The patterning device 300 performs pattern processing on the substrate S which has been subjected to exposure, thereby forming a physically structured pattern depending on the drawing data E to prepare an information recording medium M. Finally, information depending on the digital data D is recorded in the information recording medium M as a physically structured pattern.
The storage processing computer 100 is, as shown in the drawing, provided with a data input portion 110, a unit data creating portion 120, a unit bit matrix creating portion 130, a unit bit graphic pattern creating portion 140, a unit recording graphic pattern creating portion 150 and a drawing data creating portion 160. Hereinafter, a sequential description will be given of functions of these individual portions. However, these portions are in reality constituents which are realized by installing dedicated programs into a computer. The storage processing computer 100 can be constituted by installing a dedicated program into a general-purpose computer.
First, the data input portion 110 is a constituent which has functions to input the digital data D to be stored and also has functions to temporarily house the thus input digital data D. The digital data D to be stored may include any type of data such as document data, image data and voice data.
The unit data creating portion 120 is a constituent which creates a plurality of unit data by dividing the digital data D input by the data input portion 110 by a prescribed bit length unit. Here, for the sake of convenience of description, the following description will be given by taking an example in which, as shown at an upper part of
Each of the unit data Ui is not necessarily made equal in bit length and there may be created a plurality of unit data different with each other in bit length. However, it is in practice preferable that a bit recording domain Ab to be described later is given as a domain identical in shape and equal in area. For this reason, it is preferable that a common bit length u is determined in advance to give data in which all the unit data Ui have the same bit length u.
The common bit length u may be set at any given value. However, in practice, u=m×n is set so as to constitute a unit bit matrix which is composed of m rows and n columns, and the unit data creating portion 120 may divide digital data into unit data composed of (m×n) bits. Here, for the sake of convenience of description, there is shown an example in which u is set equal to 25 bits so that m=n=5 is set to constitute a unit bit matrix composed of 5 rows and 5 columns (in practice, the u value is preferably set to give a greater value). The first unit data U1 shown in
The unit data creating portion 120 may divide, for example, thus input digital data D by every u bits separately from the leading end, thereby giving unit data U1, U2, U3, etc., individually. In this case, unless an entire length of the digital data D is given as an integral multiple of the bit length u, the length of the last unit data will be less than the bit length u. Thus, where the length of all unit data is desired to be made equal to a common bit length u, a dummy bit may be added to a trailing end of the digital data to adjust so that an entire length is an integral multiple of the bit length u.
It is noted that a method for dividing the digital data D shall not be necessarily restricted to a method in which the data is divided from the leading end thereof by every prescribed bit length u and, for example, where the data is divided into four, there can be adopted such a dividing method that the 1st, 5th, 9th, . . . bits are extracted to give a first unit data U1, the 2nd, 6th, 10th, . . . bits are extracted to give a second unit data U2, the 3rd, 7th, 11th, . . . bits are extracted to give a third unit data U3, the 4th, 8th, 12th, . . . bits are extracted to give a fourth unit data U4.
Each unit data Ui created by the unit data creating portion 120 is given to the unit bit matrix creating portion 130. The unit bit matrix creating portion 130 performs processing by which data bits which constitute individual unit data Ui are arranged in a two-dimensional matrix form composed of m rows and n columns, thereby creating a unit bit matrix B(Ui).
In
Individual unit bit matrixes B(Ui) thus created by the unit bit matrix creating portion 130 are given to the unit bit graphic pattern creating portion 140. The unit bit graphic pattern creating portion 140 performs processing by which each of the unit bit matrixes B(Ui) is converted to a geometrical pattern which is arranged inside a predetermined bit recording domain on a two-dimensional plane, thereby creating a unit bit graphic pattern P(Ui).
At a middle part of
Here, each of the bit figures corresponds to a bit “1” which constitutes the unit bit matrix B(U1). In other words, a 5-row and 5-column matrix is defined inside the bit recording domain Ab so as to correspond to the unit bit matrix B(U1) and a bit figure is arranged only at a position corresponding to a bit “1” inside the unit bit matrix B(U1), with nothing arranged at a position corresponding to a bit “0.” Therefore, the unit bit graphic pattern P(U1) is to express 25-bit information which constitutes the unit bit matrix B(U1) by the presence or absence of the bit figure at each position which constitutes the 5-row and 5-column matrix.
Of course, individual bit figures may be arranged so as to correspond to bits “0” which constitute the unit bit matrix B(U1). In this case, the bit figure is arranged only at a position corresponding to a bit “0” inside the unit bit matrix B(U1) and nothing is arranged at a position corresponding to a bit “1.” That is, the unit bit graphic pattern creating portion 140 may perform processing by which, of individual bits “1” and individual bits “0,” one of them which constitute the unit bit matrix B(U1) is converted to individual bit figures in a closed domain. A data format which indicates individual bit figures may be given any format. For example, where one bit figure is constituted with a rectangle, as data showing the unit bit graphic pattern P(Ui), there can be used data which shows coordinate values of four apexes of each bit figure (coordinate values of two apexes of opposite angles will do). There can also be used data which shows a coordinate value of a center point of each bit figure (a lower left corner point will do) and data which shows lengths of vertical and horizontal sides of a bit figure having a common rectangular shape. Alternatively, where a circular bit figure is adopted, there can be used data which shows a coordinate value of a center point of each bit figure and data which shows a common radius value.
Of course, the unit bit matrixes B(U2), B(U3) and B(U4) created for the respective unit data U2, U3, U4 are also converted to a geometrical pattern by a similar method to create unit bit graphic patterns P(U2), P(U3) and P(U4). Each of the thus created unit bit graphic patterns P(UI) to P(U4) is formed on a medium by a certain method, thus making it possible to record information of the digital data D in a medium. However, in the present invention, with consideration given to the convenience of readout processing to be performed later, an alignment mark is added to each of the unit bit graphic patterns P(UI) to P(U4).
The unit recording graphic pattern creating portion 150 is a constituent which adds the alignment mark, and in the application concerned, the unit bit graphic pattern P(Ui) in a state that the alignment mark is added is referred to as a unit recording graphic pattern R(Ui). Finally, the unit recording graphic pattern creating portion 150 performs processing by which an alignment mark is added to the unit bit graphic pattern P(Ui) created by the unit bit graphic pattern creating portion 140 to create a unit recording graphic pattern R(Ui).
At the middle part of
The alignment marks Q are used for recognizing individual bit recording domains Ab in readout processing described in Section 3. Therefore, the alignment marks Q are arranged at a specific position in relation to the bit recording domain Ab (in the example shown in the drawing, positions at four corners outside the bit recording domain Ab). In the drawing, there is shown an example in which cross-shaped alignment marks Q are used. However, any shaped-figure may be used as long as it is a figure which can be distinguished from a bit figure for indicating individual bits (a small square painted in black in the example shown in the drawing).
Further, although in the example shown in the drawing, the alignment marks Q are arranged outside the bit recording domain Ab, it is possible to arrange the alignment marks Q inside the bit recording domain Ab. However, where the marks are arranged inside the bit recording domain Ab, they may interfere with a bit figure which expresses individual bits. Therefore, as shown in the example shown in the drawing, it is in practice preferable that the alignment marks Q are arranged outside the bit recording domain Ab. A description will be again given in Section 4 of a shape of the alignment mark Q and a variation of the arrangement thereof.
In this way, after creation of four sets of unit recording graphic patterns R(U1) to R(U4) by the unit recording graphic pattern creating portion 150, the drawing data creating portion 160 performs processing which creates drawing data E for drawing them. Specifically, as shown at the lower part of
A description has been so far given of processing functions of the individual constituents of the storage processing computer 100 shown in
In
As described above, the drawing data E is data which is given to the beam exposure device 200 to draw the drawing pattern P(E) on the substrate S to be exposed. Therefore, a data format thereof is required to be dependent on the beam exposure device 200 to be used. At present, where an electron beam lithography system or a laser lithography system used in designing a general LSI is used to draw any given graphic pattern, vector-format drawing data is used which indicates a contour line of the graphic pattern. Therefore, in practice, the drawing data creating portion 160 may create drawing data E which shows the contour lines of individual bit figures and alignment marks.
In
For example, the alignment mark Q1 is arranged on a grid point at which the grid lines X1 and Y1 intersect with each other, the alignment mark Q2 is arranged on a grid point at which the grid lines X1 and Y7 intersect with each other, the alignment mark Q3 is arranged on a grid point at which the grid lines X7 and Y1 intersect with each other, and the alignment mark Q4 is arranged on a grid point at which the grid lines X7 and Y7 intersect with each other.
Further, 25 grid points at which the five horizontal grid lines X2 to X6 intersect individually with the five longitudinal grid lines Y2 to Y6 correspond to the unit bit matrix B(UI) composed of 5 rows and 5 columns shown at the middle part of
In general terms, the unit bit graphic pattern creating portion 140 may perform processing by which individual bits which constitute a unit bit matrix B(Ui) composed of m rows and n columns are allowed to correspond to grid points L arranged in a matrix form composed of m rows and n columns to arrange a bit figure F with a predetermined shape on a grid point L corresponding to a bit “1” or a bit “0,” thereby creating a unit bit graphic pattern P(Ui).
Of course, figures which are contained in actual drawing data E, that is, figures contained in a drawing pattern P(E), are only individual bit figures F and individual alignment marks Q1 to Q4. In reality, there will not be drawn each of the grid lines X1 to X7 and Y1 to Y7, a contour line of the bit recording domain Ab (a broken line) and a contour line of the unit recording domain Au (a single dotted and dashed line) which are shown in the drawing.
Information which shows actual dimensions of the drawing pattern P(E) drawn on the substrate S to be exposed is also included in the drawing data E. However, the actual dimensions may be set, with consideration given to drawing accuracy of the beam exposure device 200 to be used.
At present, in pattern processing that uses a highly-accurate electron beam lithography system used in a general LSI design, it is possible to stably form a figure having a size of about 40 nm on the substrate S. Therefore,
the above-described electron beam lithography system is used as the beam exposure device 200, thus making it possible to set intervals between grid lines shown in the drawing (a pitch of grid points L) to about 100 nm. It is substantially possible to form a bit figure F having one side of about 50 nm. Where a minute graphic pattern is drawn as described above, the bit figure F will not assume in reality an exact square or the alignment marks Q1 to Q4 will not assume an exact cross-shaped form. This will not, however, pose any practical problems.
Originally, it will be sufficient that the bit figure F plays a role in judging a binary state, namely, whether a figure is present at a position of a grid point L. Thus, the bit figure F may assume any shape such as a rectangle or a circle. It is also sufficient that the alignment marks Q1 to Q4 each play a role in indicating a position of the bit recording domain Ab and they may assume any shape as long as they can be distinguished from a bit figure F. Therefore, an electron beam lithography system capable of stably forming a figure having a size of about 40 nm is used, by which, as described above, bit figures F can be arranged at a pitch of about 100 nm on both sides and highly integrated recording of information can be performed.
On the other hand, where a laser lithography system is used as the beam exposure device 200, a spot diameter of laser beams depends on a wavelength of laser light to be used, and a minimum value thereof is approximately equal to the wavelength. For example, where ArF excimer laser is used, a spot diameter thereof will be about 200 nm, and recording of information is thus slightly decreased in degree of integration, as compared with the use of an electron beam lithography system. Nevertheless, it is possible to perform recording of information with the degree of integration similar to that of a generally-used optical recording medium.
In the example shown in
Therefore, it is in practice preferable that the unit bit graphic pattern creating portion 140 creates unit bit graphic patterns P(Ui) arranged inside the rectangular bit recording domain Ab, and the unit recording graphic pattern creating portion 150 adds the alignment marks Q1 to Q4 to the exterior of the rectangular bit recording domain Ab, thereby creating unit recording graphic patterns R(Ui) arranged inside the rectangular unit recording domain Au which includes the bit recording domain Ab and the alignment marks Q1 to Q4. Accordingly, the drawing data creating portion 160 arranges these rectangular unit recording domains Au in a two-dimensional matrix manner, thereby creating a drawing pattern P(E) which includes a plurality of unit recording graphic patterns R(U1) to R(U4), thus making it possible to create the drawing data E for drawing the drawing pattern P(E).
The unit recording domain Au may be set to any size. For example, in the example of
Here, a more detailed description will be given of exposure process by the beam exposure device 200 and patterning process by the patterning device 300 shown in
In reality, semiconductor lithography systems used in an LSI manufacturing process can also be used, as they are, for the above-described devices. In other words, the beam exposure process by the beam exposure device 200 and the patterning process by the patterning device 300 can be executed by utilizing a general LSI manufacturing process as it is. However, drawing data used in manufacturing LSIs is data which shows graphic patterns for constituting individual domains of semiconductor elements, for example, a channel domain, a gate domain, a source domain, a drain domain and a wiring domain. In contrast, the drawing data E used in the present invention is data which shows a bit figure F indicating a data bit “1” or “0” and a graphic pattern for constituting an alignment mark Q used on readout.
Here, the underlying layer 10 is a layer which is to be formed in the patterning step and it is finally a part which acts as an information recording medium M in which digital data has been recorded. As already described, an object of the present invention is to attain the recording of information, with long-term durability maintained. Therefore, there may be used a substrate made of a material suitable in attaining the above-described object as the underlying layer 10. Specifically, regarding transparent materials, a glass substrate, in particular, a quartz glass substrate is optimally used as the underlying layer 10. Of course, it is also possible to use an opaque material such as a silicon substrate as the underlying layer 10. Inorganic materials such as a quartz glass substrate and a silicon substrate are materials which are less susceptible to physical damage and contaminated chemically to a lesser extent. They are materials which can be optimally used in the information recording medium of the present invention.
On the other hand, as the resist layer 20, there may be used a material suitable in giving patterning to the underlying layer 10. That is, there may be used a material having such properties that it undergoes a change in composition on exposure to electron beams or laser beams and it also functions as a protective film in an etching step given to the underlying layer 10. Of course, there may be used a positive-type resist having such properties that an exposed part will dissolve at the time of development or a negative-type resist having such properties that a non-exposed part will dissolve at the time of development.
It is noted that the substrate to be exposed S may assume any shape or may be any arbitrary dimension. A quartz glass substrate which has been now generally used as a photomask is in most cases a rectangular substrate with a standard specification of 152×152×6.35 mm. Further, as a silicon substrate, in most cases, there is used a disk-shaped wafer having about 1 mm thickness according to specifications of 6, 8 or 12 inches in diameter. As the substrate S to be exposed, there may be used a standard substrate formed as the underlying layer 10 and the resist layer 20 on an upper face thereof.
Hereinafter, for the sake of convenience of description, there will be given an example in which a quartz glass substrate is used as the underlying layer 10 and a positive-type resist is used as the resist layer 20. Therefore, the substrate S to be exposed shown in
Finally, the beam exposure device 200 shown in
The patterning device 300 is a device which gives patterning to the substrate S after completion of the exposure process. As shown in
The development processing portion 310 performs development processing by which the substrate S after exposure is immersed into a developing fluid having properties that will dissolve the exposed part 21 (where a positive-type resist is used) or the non-exposed part 22 (where a negative-type resist is used) of the resist layer, and a part thereof is performed as a remaining portion.
On the other hand, the etching processing portion 320 performs etching to the substrate S after development. In the example of
By way of the above-described processes, there is finally obtained the underlying layer 11 after being processed as shown in
Of course, in reverse to the example shown in the drawing, it is possible to adopt a recording method in which the recess C is given as a bit “0” and the protrusion V is given as a bit “1.” Whether one of them is given as a bit “0” and the other is given as a bit “1” is to be determined depending on the process described above. For example, in the case of the example described in Section 1, in the unit bit graphic pattern creating portion 140, bit figures F are arranged at positions of the grid points L corresponding to bits “1” of a unit bit matrix. On the contrary, bit figures F are arranged at positions of the grid points L corresponding to bits “0,” by which bit information on the recess and the protrusion is reversed. Where a negative-type resist is used in place of a positive-type resist as the resist layer 20, a relationship between the recess and the protrusion is also reversed.
The thus prepared information recording medium M is characterized in that it is able to perform highly integrated recording of information with long-term durability and it is also able to read out the information in a universal method.
That is, where materials such as a quartz glass substrate and a silicon substrate are used as the underlying layer 10, they are less susceptible to deterioration with the lapse of time or damage resulting from water and thermal influences than conventional information recording media such as paper, film and record disks, thereby providing durability in a semi-permanent time scale of several hundred years as with stone plates in ancient times. Of course, as compared with magnetic recording media, optical recording media and semiconductor recording media which are generally used as data recording media for computers, the information recording medium M is able to provide durability over a much longer period of time. Therefore, the present invention can be optimally used in storing information, for example, official documents in which the information is desired to be recorded semi-permanently.
Further, as described in Section 1, the beam exposure device 200 is able to perform subtle exposure by use of electron beams or laser light, thus making it possible to perform extremely highly-integrated recording of information. For example, a high-definition electron beam lithography system can be used to write bit figures F at a pitch of about 100 nm, by which it is possible to store information with a capacity of about 100 GB to 1 TB in the above-described photomask or silicon substrate with a standard size.
Further, the information recording medium according to the present invention is characterized in that since binary information of bits is directly recorded as a physical structure such as a recess and a protrusion, the information can be read out in a universal method. That is, in Patent Documents 1 and 2 described previously, there has been disclosed such technology that the cylindrical quartz glass is used as a medium to record information therein in a three-dimensional manner. In order to read out the information recorded inside the medium in a three-dimensional manner, a dedicated readout device using computer tomography or others is needed and special computation processing such as Fourier transform processing is also needed. Therefore, even if the cylindrical recording medium remains intact, for example, after several hundred years, it will be impossible to read out information without transfer of technology on a dedicated readout device.
In contrast, in the information recording medium prepared by the information storage device according to the present invention, binary information of bits is directly recorded as a physical structure. And, if a recording surface can be magnified by a certain method and recognized as an image, it is possible to read out at least the information of bits in itself. In other words, the information recording medium according to the present invention is in itself a three-dimensional structure body but recording of the bit information is definitely performed in a two-dimensional manner. Therefore, even if the information recording medium according to the present invention is found after several hundred years or several thousand years, it will be possible to read out the bit information by a universal method.
A description has been so far given of the example in which the information storage device according to the present invention is used to form a physically structured pattern having a recess and protrusion structure composed of a recess indicating one of bit “1” and bit “0” and a protrusion indicating the other of them on a surface of a quartz glass substrate or that of a silicon substrate. However, in executing the present invention, the physical structure indicating bit information is not necessarily limited to a recess and protrusion structure. Thus, a description will be given of some variations of a method in which the physical structure is formed on a medium by referring to the side cross-sectional views of
As described above, in the case of the information recording medium shown in
On the other hand,
As the added layers 31, 32, 33, the following materials may be used; light-reflective materials (for example, metals such as aluminum, nickel, titanium, silver, chromium, silicon, molybdenum and platinum as well as alloys, oxides and nitrides thereof) or light-absorbing materials (for example, materials composed of a compound such as an oxide and a nitride of metal, in the case of chromium, chromium oxide and chromium nitride). Formation of an added layer made of a light-reflective material makes it possible to distinguish a recess C from a protrusion V based on a difference in behavior of reflected light on readout. And, formation of an added layer made of a light-absorbing material makes it possible to distinguish a recess C from a protrusion V based on a difference in light absorption mode on readout. Therefore, these added layers are formed to obtain an effect that information can be read out more easily.
Further, a similar effect can be obtained by doping impurities on a surface of a recess C or that of a protrusion V in place of forming another layer having a clear border face like the added layer. For example, an information recording medium having a recess and protrusion structure is constituted with quartz, and on the surface of the medium, boron, phosphorus, rubidium, selenium and copper are doped to make the impurity concentrations different on the surface thereof. Thereby, as with a case where the added layer is provided, the surface can be given light reflectivity or light absorbency to obtain an effect of reading out information more easily. Specifically, in the case of the above-described impurities, there is obtained an effect of absorbing ultraviolet rays at concentrations of about 100 ppm or more, and there is obtained an effect of increasing reflectance at concentration of about 1000 ppm or more.
In particular, as shown in the example of
As shown in the example of
On the other hand, the modified example shown in
Where the modified example shown in
On the other hand, where the modified examples shown in
In Section 1 and Section 2, a description has been given of the constitution and motions of the information storage device for storing information in the information recording medium. Here, a description will be given of a constitution and motions of the information readout device for reading out the thus recorded information.
Here, the image photographing device 400 is a constituent which magnifies and photographs a domain to be photographed which is a part of a recording surface of the information recording medium M and captures the thus photographed image as image data. As shown in the drawing, it is provided with an imaging element 410, a magnifying optical system 420 and a scanning mechanism 430.
The imaging element 410 can be constituted, for example, with a CCD camera and has functions to capture, as digital image data, images inside a predetermined domain to be photographed. The magnifying optical system 420 is constituted with optical elements such as lenses and plays a role in magnifying a predetermined domain to be photographed which constitutes a part of the recording surface of the information recording medium M and forming the magnified image on an image surface of the imaging element 410. Then, the scanning mechanism 430 plays a role in giving scanning processing (change in position and angle) to the imaging element 410 and the magnifying optical system 420 so that the domain to be photographed moves sequentially on the recording surface of the information recording medium M.
In
As shown in the drawing, the readout processing computer 500 is provided with a photographed-image housing portion 510, a bit-recording-domain recognizing portion 520, a unit-bit-matrix recognizing portion 530, a scanning controller 540 and a data restoration portion 550. Hereinafter, a description will be sequentially given of functions of these portions. However, the portions are constituents which are in reality provided by installing a dedicated program into a computer. The readout processing computer 500 can be constituted by installing a dedicated program into a general-purpose computer.
First, the photographed-image housing portion 510 is a constituent which houses photographed images photographed by the image photographing device 400. That is, it has functions to house, as digital image data, images photographed by the imaging element 410 inside a predetermined domain to be photographed. As described above, the image photographing device 400 is provided with the scanning mechanism 430, and the domain to be photographed moves sequentially on the recording surface of the information recording medium M to obtain a newly photographed image at every movement by the imaging element 410. The photographed-image housing portion 510 thus performs functions to house individual image data sequentially given from the imaging element 410.
On the other hand, the bit-recording-domain recognizing portion 520 performs processing by which individual bit recording domains Ab are recognized from photographed images housed in the photographed-image housing portion 510. In the present invention, as described by referring to
As described in Section 2, alignment marks Q and bit figures F are recorded on the recording surface of the information recording medium M, as physically structured patterns which have a recess and protrusion structure or a structure in which through holes are present or absent. Resultantly, the alignment marks Q and bit figures F or their contours are expressed in terms of distribution of brightness and darkness on a photographed image. An existing pattern-recognizing technology can be used to recognize the alignment marks Q and bit figures F on the photographed image.
First, recognition of individual bit recording domains Ab is performed by detecting an alignment mark Q. Since a figure different from the bit figure F is used in the alignment mark Q, the bit-recording-domain recognizing portion 520 is able to detect the alignment mark Q by searching the interior of a photographed image housed in the photographed-image housing portion 510. For example, in the example shown at the lower part of
The alignment mark Q is arranged at a specific position in relation to the bit recording domain Ab. Therefore, if the alignment mark Q can be recognized on a photographed image, it is possible to identify the position of the bit recording domain Ab. For example, where the unit recording graphic pattern R(U1) shown in
If the image photographing device 400 has functions to photograph a domain to be photographed with a size which can include at least one unit recording domain Au, search is conducted inside the photographed image, thus making it possible to recognize four sets of the alignment marks Q1 to Q4 shown in
Of course, if the domain to be photographed is set at a position across mutually-adjacent unit recording domains Au, four sets of the alignment marks Q1 to Q4, each of which indicates the position of the same bit recording domain Ab, would not be correctly recognized. In this case, the bit-recording-domain recognizing portion 520 is able to understand a positional deviation of the domain to be photographed on the basis of a mutual relationship of the recognized alignment marks and performs processing by which the positional deviation is reported to the scanning controller 540.
When the positional deviation is reported, the scanning controller 540 controls the image photographing device 400 so as to adjust the positional deviation concerned. Specifically, the controller gives instructions to the scanning mechanism 430 so that the domain to be photographed is allowed to move only by a predetermined correction amount in a predetermined correction direction. The above-described correction makes it possible to obtain a correct photographed image where the alignment marks Q1 to Q4 are arranged at four corners appropriately as shown in
A second role of the scanning controller 540 is to perform scanning processing for setting a next unit recording domain Au as a new domain to be photographed after completion of photography in which one unit recording domain Au is given as a domain to be photographed. For example, in the example shown at the lower part of
Consequently, the scanning controller 540 is to be a constituent which controls the change of a domain to be photographed by the image photographing device 400 so that a photographed image can be obtained in all the bit recording domains to be read out. The control can be attained by feedback control on the basis of detection results of the alignment marks Q by the bit-recording-domain recognizing portion 520. A slight adjustment can also be made as described above even where the positional deviation takes place.
Then, when the bit-recording-domain recognizing portion 520 recognizes an i-th bit recording domain Ab(i) from a photographed image, information of the i-th bit recording domain Ab(i) is given to the unit-bit-matrix recognizing portion 530. The unit-bit-matrix recognizing portion 530 performs processing by which a unit bit matrix is recognized on the basis of a pattern inside the bit recording domain Ab(i). For example, in the example shown in
In the example shown in
First, the horizontal grid lines X1 and X7, and the longitudinal grid lines Y1 and Y7 are recognized on the basis of the center point positions of four sets of the alignment marks Q1 to Q4 recognized by the bit-recording-domain recognizing portion 520. Next, the horizontal grid lines X2 to X6 are defined so as to divide equally a space between the horizontal grid lines X1 and X7, and the longitudinal grid lines Y2 to Y6 are defined so as to divide equally a space between the longitudinal grid lines Y1 and Y7. Then, there may be performed processing by which positions of 25 grid points at which the horizontal grid lines X2 to X6 intersect with the longitudinal grid lines Y2 to Y6 are determined to judge whether a bit figure F is present at each position of these grid points or not. As described above, the bit figure F can be recognized on the basis of distribution of brightness and darkness on a photographed image. Therefore, a bit “1” is allowed to correspond to a position of a grid point at which the bit figure F is present and a bit “0” is allowed to correspond to a position of a grid point at which it is not present, thus making it possible to obtain the unit bit matrix B(U1) composed of five rows and five columns shown at the middle part of
The unit-bit-matrix recognizing portion 530 thus performs processing by which an i-th unit bit matrix B(Ui) is recognized on the basis of an i-th unit bit graphic pattern P(Ui) recorded inside an i-th bit recording domain Ab(i) and gives the result thereof to the data restoration portion 550. The unit-bit-matrix recognizing portion 530 will repeatedly execute processing for recognizing a unit bit matrix by the same method with regard to all the bit recording domains recognized by the bit-recording-domain recognizing portion 520.
The data restoration portion 550 performs processing by which unit data Ui is created from individual unit bit matrixes B(Ui) recognized in this way by the unit-bit-matrix recognizing portion 530 to synthesize individual unit data Ui, thereby restoring the digital data D stored. For example, in the example shown in
A description has been so far given of the basic embodiment of the information readout device according to the present invention by referring to the block diagram of
The information recording medium M prepared by the information storage device according to the present invention is, as described previously, provided with universality that binary information of bits is directly recorded as a physical structure. Then, if a recording surface can be magnified by some method to obtain an image showing the presence or absence of a bit figure F, bit information can be read out. Therefore, even if the information recording medium M is found after several hundred years or several thousand years and if some means for recognizing the physical structure is available at the age concerned, the bit information can be read out. Of course, where the medium is found in a state of being buried underground, a recording surface may be contaminated by attached foreign matter. However, the foreign matter can be easily removed by washing and the information can be read out without any difficulty.
Adoption of any readout method makes it possible to read out information in a non-contact state on an information recording surface (where an atomic force microscope is used, information can be read out in a non-contact state by use of a non-contact mode). At the time of readout processing, there is no chance that the recording surface may be physically damaged and even on repetition of readout processing, there is no fear that the information recording surface may wear away.
Further, the information readout device shown in
In Section 3, a description has been given of the basic embodiment of the information readout device. Thus, here, with consideration given to convenience at the time of reading out the information, a description will be given of variations of alignment marks recorded at the time of information storage. The bit figure F plays a role in indicating original information to be stored, whereas the alignment marks Q are to be meta information which is used for alignment at the time of reading out information.
In the embodiment described above, the unit recording graphic pattern creating portion 150 performs processing by which the cross-shaped alignment marks Q1 to Q4 are added respectively to four corners outside a rectangular bit recording domain Ab, for example, as shown in
However, a shape, an arrangement position and a number of the alignment marks Q shall not be limited to those of the above-described embodiment. That is, each of the alignment marks Q may assume any shape as long as it can be distinguished from the bit figure F. Further, they are not necessarily required to be arranged at four corners outside a bit recording domain Ab and, for example, they may be arranged at a central position between four sides of the bit recording domain Ab. Still further, the number of the alignment marks Q is not necessarily limited to four sets.
Of course, alignment marks may be individually arranged at an upper left corner and a lower left corner in the vicinity of the bit recording domain Ab to define a longitudinal coordinate axis Y. That is, the unit recording graphic pattern creating portion 150 may create a unit recording graphic pattern by adding a total of two sets of alignment marks to two corners not at a diagonal position, of four corners arranged outside in the vicinity of a rectangular bit recording domain Ab.
On the other hand,
As described above, where three sets of alignment marks are used, as shown in the example of
That is, where a row number i (i=1, 2, 3, . . . ) and a column number j (j=1, 2, 3, . . . ) are defined for an arrangement of the unit recording domains Au to express individual unit recording domains as A (ij), as shown in the drawing, in a first group in which (i+j) is an even number, there is adopted an arrangement mode in which no alignment mark is given only to a lower right corner as shown in
As described above, three sets of the alignment marks are defined in two types of arrangement modes and there is adopted a vertically- or laterally-adjacent unit recording graphic pattern in which the marks are arranged in a mutually different mode. Thereby, it is possible to prevent an error of omitting photography of an adjacent unit recording domain when the scanning controller 540 scans a domain to be photographed.
For example, in the example shown in
If there is adopted the arrangement mode shown in
As a method for recognizing occurrence of the omission, there is a method for providing two types of arrangement modes. In addition, it is possible to adopt a method for changing the shape of an alignment mark. For example,
Where the variation shown in
That is, if the image photographing device 400 of the information readout device shown in
Of course, in this case as well, as described by referring to
Further, as a method for indicating the reference unit recording domain Au(11), there can be adopted a method in which bit figures F are not arranged at the bit recording domain Ab(11) inside the reference unit recording domain Au(11) but a unique identification mark is arranged, in place of adopting a method for using reference alignment marks different from those of other unit recording domains. The bit recording domain Ab is a domain which is originally used for recording data to be stored by arranging bit figures F. However, the unique identification mark is arranged only at the reference unit recording domain, thus making it possible to easily recognize the reference unit recording domain by confirming the unique identification mark.
For example, a large star mark is drawn in the domain Au(11) shown in
Finally, a description will be given of basic processing procedures where the present invention is understood as an invention of process, that is, an information storage process and an information readout process.
First, in Step S11, the storage processing computer 100 executes a data input step in which digital data D to be stored is input. In subsequent Step S12, the storage processing computer 100 executes a unit data creating step in which the digital data D is divided by a prescribed bit length unit to create a plurality of unit data Ui. Then, in Step S13, the storage processing computer 100 executes a unit bit matrix creating step in which data bits which constitute individual unit data Ui are arranged in a two-dimensional matrix form to create a unit bit matrix B(Ui). In Step S14, the storage processing computer 100 executes a unit bit graphic pattern creating step in which the unit bit matrix B(Ui) is converted to a geometrical pattern arranged inside a predetermined bit recording domain Ab to create a unit bit graphic pattern P(Ui).
Then, in Step S15, the storage processing computer 100 executes a unit recording graphic pattern creating step in which alignment marks Q are added to the unit bit graphic pattern P(Ui) to create a unit recording graphic pattern R(Ui). Then, in Step S16, the storage processing computer 100 executes a drawing data creating step which creates drawing data E for drawing the unit recording graphic pattern R(Ui).
Then, lastly, in Step S17, there is executed a beam exposure step in which electron beams or laser light is used to effect beam exposure on the substrate S which is an information recording medium on the basis of the drawing data E. In Step S18, there is executed a patterning step in which pattern processing is performed on the exposed substrate to create an information recording medium M in which a physically structured pattern is formed depending on the drawing data E.
In contrast,
First, in Step S21, there is executed an image photographing step in which the image photographing device 400 is used to magnify and photograph a domain to be photographed which is a part of a recording surface of the information recording medium M to capture the thus obtained photographed image as image data. Then, in Step S22, there is executed a photographed-image housing step in which the readout processing computer 500 houses the photographed-image. In Step S23, there is executed a bit-recording-domain recognizing step in which the readout processing computer 500 detects alignment marks from the photographed-image housed in the photographed-image housing step to recognize individual bit recording domains Ab.
Where a bit recording domain Ab has been successfully recognized in the bit-recording-domain recognizing step, procedures move to Step S25 by way of Step S24. Where there is a failure in recognizing a bit recording domain Ab, that is, where a positional deviation occurs at the time of taking a photograph and a complete bit recording domain Ab is not included in a photographed-image, the procedures return to Step S21 and the image photographing step is executed again. At this time, the image photographing device performs processing by which a domain to be photographed is changed so that a correct photographed image can be obtained.
In Step S25, there is executed a unit-bit-matrix recognizing step in which the readout processing computer 500 recognizes a unit-bit-matrix B(Ui) on the basis of a pattern inside the bit recording domain Ab. The processing is executed repeatedly by way of Step S26 until all necessary domains are completely recognized. That is, the change of domains to be photographed is controlled by the image photographing device so that photographed-images of all the bit-recording-domains Ab to be read out are obtained by the readout processing computer 500, thereby repeating a series of processing from Step S21 of the image photographing step.
Lastly, in Step S27, there is executed a data restoration step in which the readout processing computer 500 creates unit data Ui from individual unit-bit-matrixes B(Ui) recognized in the unit-bit-matrix recognizing step of Step S25 to synthesize individual unit data Ui, thereby restoring digital data D to be stored.
The plate-like information recording medium described above has front, back, top, bottom, left and right sides. And, upon reading out recorded information, it is necessary to correctly recognize the front, back, top, bottom, left and right sides of the medium and perform readout processing. Thus, when information is recorded in a plate-like medium in general, there has been proposed a method for adding an identification mark for indicating a direction to perform correct readout processing. For example, in Patent Document 3 described previously, there has been disclosed the technology in which the identification mark composed of a recess and protrusion structure is provided at a lower right corner on a surface of a card-like information recording medium to recognize a direction of the medium by a sense of touch, thus making it possible to insert the plate-like information recording medium into an information reader in a correct direction.
In the information storage device according to the present invention, information is recorded on the basis of a predetermined graphic pattern. Even where the same graphic pattern is used to perform beam exposure and pattern processing, a physical structure actually formed on a substrate differs depending on the adopted method for beam exposure and pattern processing. For example, where a bit “0” and a bit “1” are recorded separately as a recess and protrusion structure formed on a substrate, the protrusion is given as a bit “1” or the recess is given as a bit “1,” depending on the adopted method for beam exposure and pattern processing.
Specifically, recording results on the medium will be different depending on whether a domain indicating a bit “0” is exposed or a domain indicating a bit “1” is exposed at the time of beam exposure. Similarly, recording results on the medium will also be different depending on the conditions of pattern processing in which a positive-type resist is used or a negative-type resist is used as the resist layer formed on a substrate. It is, therefore, impossible to recognize whether information is to be read out by interpreting the protrusion as a bit “1” or interpreting the recess as a bit “1” only by referring to the information on data bits which has been recorded in the information recording medium concerned.
Here, by referring to the drawings, a detailed description will be given of problems relating to a method for interpreting data bits occurring when information is recorded on a medium as a minute physically structured pattern by the method described above.
In
As shown in
The information recording medium M1 shown in
As described above, if a method for interpreting individual data bits (in this example, which of the recess and the protrusion is interpreted as a bit “1” or a bit “0”) differs at the time of reading out data, a bit value will be reversed. And, it is therefore impossible to read out correct bit information which has been intended at the time of recording. Of course, the unit bit graphic pattern P(U1) shown in
With the above situation taken into account, it is preferable that certain information which shows a method for interpreting data bits is also recorded in the information recording medium M in itself at the time of recording data. For example, in the above-described example, information composed of a character string of “the recess is a bit “1”” is written onto the information recording medium M in a macroscopically-visible manner at the time of recording data. Thereby, it is possible to interpret individual data bits by a correct method on the basis of this information at the time of readout. Of course, if a method for interpretation is shown, with attention always given to a bit “1,” the text “recess” may be simply written in a macroscopically-visible manner.
Specifically, an operator who performs information readout processing by using the information readout device shown in
However, where the method for interpreting data bits is recorded in a medium in itself, such a method is not practically preferable that information of “the recess being a bit “1”” is recorded simply in the medium as described in the above example. Reasons thereof will be described hereinafter.
A first reason is that where a physical method is employed to reproduce a medium, it is impossible to give a correct response. At present, information recording media such as CDs and DVDs that record music and images are distributed in the market as commercial mass-produced products. These mass-produced media are ordinarily produced by way of a physical reproduction process on the basis of a master copy. In reproductions made by way of the above-described reproduction process, a recess and protrusion structure of the master copy is reversed.
Therefore, a correct method for interpreting data bits on the information recording medium M2 shown in
As described above, where what-is-called, “reversal of a pattern (inside out)” takes place, as a technique for gaining the attention of an operator to the reversal, there is a method for recording an identification mark with an asymmetric shape, and this method has been conventionally known. For example, where a transparent manuscript sheet is used to create a printed matter by an optical process and if the manuscript sheet is set inside out, an inside-out image is formed on the printed matter. In order to prevent the above-described error, an identification mark having an asymmetric shape may be recorded on the manuscript sheet. For example, a capital letter “F” is recorded as an identification mark, by which when the manuscript sheet is set inside out, the letter “F” is a reversed letter (mirror letter). And, an operator is able to easily recognize that the sheet has been set inside out.
Thus, in the above-described basic embodiment as well, a method for recording an identification mark having an asymmetric shape is adopted to gain the attention of a readout operator that a recess and a protrusion are reversed, where a recess and protrusion structure of the master copy is reversed by a reproduction process.
Here, the major recording domain Aα is a domain for recording information on individual data bits which constitute digital data to be recorded, and, specifically, it is a domain in which the unit recording domains Au shown in
On the other hand,
The medium M2 (a reproduction) shown in
As described above, where the reproduction is repeated successively, an interpretation to be adopted for data bits of individual edits can be recognized by referring to the identification mark m1 or m2 recorded at the minor recording domain AB. That is, when the identification mark m1 which indicates a regular letter “F” is recorded, the recess C may be interpreted as a bit “1” and when the identification mark m2 which indicates a reversed letter “F” is recorded, the recess C may be interpreted as a bit “0.” Of course, as an identification mark, there may be used such a character string that “the recess is a bit “1.”” In this case, when the character string that “the recess is a bit “1”” is described by correct letters, the recess may be interpreted as a bit “1” literally. When the character string is given by reversed letters, the recess may be interpreted as a bit “0” instead.
As described above, even where the physical pressing process is used to reproduce a medium and a recess and protrusion structure of the master copy is assumed to be reversed, such a method is adopted that an identification mark having an asymmetric shape is recorded at the minor recording domain AB, thus making it possible to notify a readout operator of a correct method for interpreting data bits.
However, as described previously in the basic embodiment, where beam exposure and pattern processing are performed on the substrate to record information as a minute physically structured pattern, there may be found such a case that a method for recording an identification mark having an asymmetric shape is not necessarily able to notify a correct method for interpreting data bits. This is derived from a second reason which will be described below.
The second reason why the method for simply recording a method for interpreting data bits as “the recess is a bit “1”” in a medium as it is, is not preferable is that even where the same graphic pattern is used to perform beam exposure and pattern processing, a physical structure actually formed on a substrate will be different depending on the adopted method for beam exposure and pattern processing.
For example, in the case of the process of the beam exposure and pattern processing shown in
Then, etching is performed, by which, as shown in
Here, the information recording medium M1 shown in
As described above, a description has been given of an example in which the method for interpreting data bits on a recess and protrusion structure formed on a medium is reversed depending on whether a positive-type resist or a negative-type resist is used as the resist layer 20 upon performance of pattern processing. The method for interpreting data bits on a recess and protrusion structure formed on a medium is reversed also depending on whether the interior of a bit figure F is exposed or the exterior thereof is exposed upon performance of beam exposure processing.
This means that even where in the information storage device shown in
Therefore, as shown in
That is, where a medium is prepared by the process shown in
On the other hand,
As described above, where beam exposure and pattern processing are performed on a substrate to record information as a minute physically structured pattern, it is impossible to transmit a correct method for interpreting data bits by the method for recording an identification mark with an asymmetric shape.
Thus, in the present application, in order to deal with the above-described problem, there is proposed a new technique for recording information which shows a method for interpreting data bits. A detailed description will be given of the new technique in Section 7 and thereafter. Here, for the sake of convenience of description, a description will be given of an example in which the new technique is applied to the basic embodiment described in Section 1 to Section 5. However, the technique described in Section 7 and thereafter shall not be limited to application to the information storage process according to the basic embodiment described in Section 1 to Section 5. This technology can be widely applied to an information storage process which records information as a minute physically structured pattern by performing beam exposure and pattern processing to a substrate.
The above-described new technique for recording information which shows a method for interpreting data bits can be executed by an information storage device with functions to record an identification mark.
On the other hand, the storage processing computer 100′ of the information storage device shown in
The main information pattern creating portion 170 shown in
As shown in the drawing, the main information pattern creating portion 170 is constituted with a unit data creating portion 120, a unit bit matrix creating portion 130, a unit bit graphic pattern creating portion 140 and a unit recording graphic pattern creating portion 150. And, these individual constituents are the same as individual constituents indicated with the same symbols in
On the other hand, the minor information pattern PB created by the minor information pattern creating portion 180 is a pattern showing a method for interpreting data bits indicated by the main information pattern Pa and performs similar functions as those of the identification marks m1 and m3 shown in
The drawing-data creating portion 160′ defines the major recording domain Aα and the minor recording domain Aβ on a surface to be drawn, arranges the main information pattern Pa created by the main information pattern creating portion 170 at a major recording domain Aα and arranges the minor information pattern P6 created by the minor information pattern creating portion 180 at a minor recording domain Aβ to create a synthesis pattern, thereby creating drawing data E for drawing the synthesis pattern.
On the basis of the thus created drawing data E, the beam exposure device 200 performs beam exposure by using electron beams or laser light on a substrate S which is an information recording medium, and the patterning device 300 which is provided with a development processing portion 310 and an etching processing portion 320 performs pattern processing on the exposed substrate S, thereby creating an information recording medium M in which a physically structured pattern is formed in accordance with the drawing data E. This is the same with the information storage device shown in
That is, in the substrate having an underlying layer and a resist layer which covers the underlying layer, the beam exposure device 200 performs beam exposure on a surface of the resist layer. The development processing portion 310 performs processing by which the substrate is immersed into a developing fluid having properties to dissolve an exposed part or a non-exposed part of the resist layer, allowing a part of the resist layer to remain as a remaining part. The etching processing portion 320 etches the underlying layer by using the remaining part of the resist layer as a mask. At this time, the beam exposure device 200 may expose the interior of a bit figure F or may expose the exterior thereof. Further, a positive-type resist or a negative-type resist may be used as the resist layer.
Finally, the information storage device according to the basic embodiment shown in
Of course, the minor information pattern creating portion 180 newly added to the latter is also a constituent built by actually installing a program into a computer. The data input portion 110, the main information pattern creating portion 170, the minor information pattern creating portion 180 and the drawing-data creating portion 160′ which are constituents of the storage processing computer 100′ shown in
Then, a description will be given of the minor information pattern P6 which is created by the minor information pattern creating portion 180. Here, first, the patterning device 300 of the information storage device shown in
The medium M5 shown in
As described above, the medium M5 shown in
As described above, the medium M5 shown in
In the case of the example shown in the drawing, the minor information pattern PG recorded at the minor recording domain Aβ is constituted with a first identification mark m10 recorded at the first minor recording domain Aβ1 and a second identification mark m20 recorded at the second minor recording domain Aβ2. Specifically, the first identification mark m10 is constituted with a closed domain which indicates a symbol “protrusion,” and the second identification mark m20 is constituted with a closed domain which indicates a symbol “recess,” functioning as a mark which shows a correct method for interpreting data bits in view of “which identification mark looks brighter.”
Here, for the sake of convenience, mesh hatching and dot hatching are given inside the closed domains which constitute the two identification marks m10 and m20 shown in each of the drawings, and the domain to which the mesh hatching has been given is to be observed brighter than the domain to which the dot hatching has been given. Therefore, in the medium M5 shown in
Moreover, the example given here shows a method in which where the symbol “recess” looks brighter, the recess C is interpreted as a bit “1,” and where the symbol “protrusion” looks brighter, the protrusion V is interpreted as a bit “1.” Therefore, since the symbol “recess” looks brighter for a readout operator who has the medium M5 shown in
Further, where the previously described pressing process is used to prepare a reproduction, a recess and protrusion structure of the reproduction which has been prepared by using the medium M5 shown in
Then, a description will be given of a physical structure of the first identification mark m10 and that of the second identification mark m20. The pair of identification marks m10, m20 recorded at the minor recording domain Aβ are required to play a role in presenting a correct method for interpreting data bits to a readout operator by the above-described method. Therefore, they each have a structure which is closely related to data bits recorded at the major recording domain Aα. First, consideration is given to characteristics of the data bits recorded at the major recording domain Aα.
As described previously, the main information pattern Pα created by the main information pattern creating portion 170 is recorded at the major recording domain Aα. The main information pattern Pα is, for example, given as an assembly (i=1, 2, 3, . . . ) of the unit recording graphic pattern R(Ui) shown in
Specifically, in the example shown in
The main information pattern creating portion 170 shown in
In
Similarly, in
In general terms, if one of the above-described “black domain” and “white domain” is referred to as a “first attribute main domain” and the other is referred to as a “second attribute main domain,” the main information pattern Pα is constituted with the first attribute main domain and the second attribute main domain. And, it is a pattern which expresses binary information of individual data bits depending on whether a predetermined point corresponding to each of the data bits (in the example shown in
In the example described here, the main information pattern creating portion 170 converts one of individual bits “1” and individual bits “0” which constitute digital data D to be stored (in the example shown in
On the other hand, the minor information pattern PB created by the minor information pattern creating portion 180 is, as shown in
As described previously, a readout operator understands the method for interpretation indicated by a mark which looks brighter, of the pair of identification marks m10, m20, as a correct method for interpreting data bits.
Then, a description will be given of an actual case of the pair of identification marks m10, m20, by referring to
As described previously, the main information pattern Pα which is to be recorded at the major recording domain Aα is a pattern in which domains having two types of attributes which are the “black domain” and the “white domain” are mixed. The minor information pattern P6 which is to be recorded at the minor recording domain Aβ is also a pattern in which domains having two types of attributes of the “black domain” and the “white domain” are mixed.
At a lower part of
A magnified image of the part domain p3 given at the lower part of
On the other hand, as apparent from the magnified images of the part domains p1 and p2 shown at the lower part of
That is, the patterns inside the closed domain which constitute the identification marks m10, m20 respectively constitute a striped pattern which is composed of “black domains” and “white domains,” as shown in magnified images of the part domains p1 and p2. This is because where the pattern is recorded as a recess and protrusion structure on the medium M, there is formed a diffraction grating for visible light inside the identification marks m10, m20. Finally, there is formed a pattern in which a narrow band-like “black domain” and a narrow band-like “white domain” are alternately arranged at the closed domain which constitutes the identification marks m10, m20.
Individual grid lines which form the diffraction grating are set so as to be parallel with a common arrangement axis Z. The example shown in the drawing is such that the arrangement axis Z is set as an axis extending in a vertical direction in the drawing and, therefore, striped patterns extending in a vertical direction are formed inside the part domains p1, p2. Of course, the arrangement axis Z may be set in any given direction.
Here, it is important that comparison of the striped patterns inside the part domain p1 with the striped patterns inside the part domain p2 reveals that a dimensional relationship between a width W1 of a band which constitutes a “black domain” (the first attribute minor domain g1) and a width W2 of a band which constitutes a “white domain” (the second attribute minor domain g2) are reversed with each other. Specifically, in the example shown in the drawing, the relationship is W1>W2 at the part domain p1 inside the identification mark m10, whereas it is W1<W2 at the part domain p2 inside the identification mark m20. A difference in dimensional relationship between these widths will result in a difference in brightness and darkness on observation, the details of which will be described later.
In the drawing, there are depicted only patterns inside the encircled part domains p1, p2. Of course, a pattern similar to that at the part domain p1 is formed entirely at a closed domain inside the symbol “protrusion” which constitutes the identification mark m10, and a pattern similar to that at the part domain p2 is formed entirely at a closed domain inside the symbol “recess” which constitutes the identification mark m20. In other words, the interior of the symbol “protrusion” and the interior of the symbol “recess” are filled with striped patterns extending in a vertical direction in the drawing.
In the example shown here, a background part inside the first minor recording domain Aβ1 (a domain outside the symbol “protrusion”) and a background part inside the second minor recording domain Aβ2 (a domain outside the symbol “recess”) are constituted with a “white domain” (the second attribute minor domain g2). These background parts may be constituted with a “black domain” (the first attribute minor domain g1).
Alternatively, a striped pattern composed of a “black domain” and a “white domain” (a pattern functioning as a diffraction grating on a medium) may be formed also at the background parts. It is, however, necessary that the stripe pattern is constituted so that a readout operator is able to recognize a contour of the symbol “protrusion” and a contour of the symbol “recess” on observation. Where striped patterns (diffraction grating) are formed also at the background parts, such consideration is needed that they are made different in direction or pitch from the striped patterns (diffraction grating) inside an identification mark by which a contour of the identification mark can be recognized on observation. Therefore, it is in practice preferable that the background part is given as a “white domain” or a “black domain.”
Eventually, there is arranged a pattern in which a “black domain” and a “white domain” are mixed at a part of the major recording domain Aα and also at a part of the minor recording domain Aβ. The drawing pattern P(E) is an assembly of many closed domains belonging to one of two types of the domains. In general terms, the main information pattern Pα arranged at the major recording domain Aα is a pattern in which the first attribute main domain G1 (for example, a “black domain”) and the second attribute main domain G2 (for example, a “white domain”) are mixed. The minor information pattern PB arranged at the minor recording domain Aβ is a pattern in which the first attribute minor domain g1 (for example, a “black domain”) and the second attribute minor domain g2 (for example, a “white domain”) are mixed.
Here, if the “first attribute” domain is given as a domain in which beam exposure is performed and the “second attribute” domain is given as a domain in which no beam exposure is performed, in the case of the above example, the “black domain” is subjected to exposure and the “white domain” is not subjected to exposure. In other words, in this case, the drawing data creating portion 160′ creates drawing data E for performing exposure on the first attribute main domain G1 and the first attribute minor domain g1 and not giving exposure to the second attribute main domain G2 and the second attribute minor domain g2. Of course, instead, the “second attribute” domain may be given as a domain in which beam exposure is performed, and the “first attribute” domain may be given as a domain in which no beam exposure is performed.
As already described, depending on which of the attribute domains is subjected to beam exposure on beam exposure processing, or which of a positive-type and a negative-type resists is used on pattern processing, the “first attribute” domain is changed to a protrusion V or changed to a recess C on the medium M (in other words, the “second attribute” domain is changed to a recess C or changed to a protrusion V on the medium M).
However, here, it is important that where the first attribute main domain G1 is given as a protrusion V finally on the medium M, the first attribute minor domain g1 is also given as a protrusion V, and where the first attribute main domain G1 is given as a recess C, the first attribute minor domain g1 is also given as a recess C. Of course, where the second attribute main domain G2 is given as a protrusion V, the second attribute minor domain g2 is also given as a protrusion V, and where the second attribute main domain G2 is given as a recess C, the second attribute minor domain g2 is also given as a recess C. This is an unchangeable universal matter, regardless of which of the attribute domains is subjected to beam exposure on beam exposure processing or which of a positive-type and a negative-type resists is used on pattern processing.
Therefore, a medium M prepared on the basis of the drawing pattern P(E) shown in
In the case of this example, the drawing pattern P(E) expresses a bit “1” by a bit figure F composed of a “black domain.” Therefore, where readout processing is performed on the “black protrusion medium,” there may be adopted a method that “the protrusion is interpreted as a bit “1.”” Where readout processing is performed on the “black recess medium,” there may be adopted a method that “the recess is interpreted as a bit “1.”” Therefore, a readout operator may only recognize that a target medium is the “black protrusion medium” or the “black recess medium.” As described previously, the operator is able to recognize it by referring to which of the pair of identification marks looks brighter.
For example, in the case of the example shown in
Side cross-sectional views of the domains p1, p2 given at the lower part of
On the other hand,
In side cross-sectional views of the part domains p1, p2 at the lower part of
Then, consideration will be given of the black recess medium M shown in
First, as shown in
Of course, of the illumination light which has been made incident on a recess, some of the light is directed upward as it is after reflection. However, in general, it is less probable that illumination light made incident on a recess is observed from above. This is because, as shown in
That is, in
Here, at the part domain p1 shown in
On the other hand, at the part domain p2 shown in
Consequently, when the black recess medium M5 shown in
Next, consideration will be given of the black protrusion medium M6 shown in
Originally, as shown in
Here, at the part domain p1 shown in
On the other hand, at the part domain p2 shown in
Consequently, when the black protrusion medium M6 shown in
The present invention is advantageous in that the storage processing computer 100′ is used to prepare drawing data E for drawing the drawing pattern P(E) shown at the upper part of
In other words, the first attribute domains indicated as “black domains” at the lower part of
As described previously, a stripe-shaped recess and protrusion structure formed inside each of the identification marks m10, m20 on the medium constitutes in reality a diffraction grating. Therefore, light observed by a readout operator is diffracted light by the diffraction grating. Therefore, the operator who has the “black recess medium” shown in
Of course, upon observation of the symbol “protrusion” and the symbol “recess,” absolute brightness of each symbol differs depending on an illumination environment and also different depending on a direction at which a medium is held. However, the diffraction grating formed inside the symbol “protrusion” and that formed inside the symbol “recess” face in the same direction (a direction parallel to the arrangement axis Z shown in
As described above, according to the present invention, beam exposure and pattern processing are performed on a substrate, thus making it possible to record also information which shows a method for interpreting data bits when the information is recorded as a minute physically-structured pattern.
Eventually, characteristics of the identification marks m10, m20 described in Section 8 will be summarized as follows. First, as shown also in the example of
Moreover, the closed domain which constitutes the first identification mark m10 is set so that the width W1 of the first attribute minor domain g1 is greater than the width W2 of the second attribute minor domain g2. The closed domain which constitutes the second identification mark m20 is set so that the width W2 of the second attribute minor domain g2 is greater than the width W1 of the first attribute minor domain g1.
On the other hand, as shown at the part domain p3 in
At this time, the drawing data creating portion 160′ creates the drawing data E by which the first attribute main domain G1 and the first attribute minor domain g1 are exposed but the second attribute main domain G2 and the second attribute minor domain g2 are not exposed, or creates the drawing data E by which the second attribute main domain G2 and the second attribute minor domain g2 are exposed but the first attribute main domain G1 and the first attribute minor domain g1 are not exposed, wherein the first attribute minor domain g1 and the second attribute minor domain g2 are formed with such width dimensions that they are able to constitute a diffraction grating for visible light.
At an upper part of
It is, therefore, necessary that the width W1 of the “black domain” (the first attribute minor domain g1) and the width W2 of the “white domain” (the second attribute minor domain g2) formed on an actual medium are set in such a width that a diffraction grating for visible light can be formed.
On the other hand, a difference between the width W1 and the width W2 causes a difference in brightness and darkness when these two identification marks m10, m20 are compared and observed. Therefore, it is, in practice, preferable that the difference should be made great as possible within a range which will not impair functions as the diffraction grating. The inventor of the application concerned conducted an experiment in which an actual medium was prepared by setting the width W1 and the width W2 to various dimensions, finding that when a ratio of the width W1 to the width W2 was set to be at least 5 times greater, a difference in brightness and darkness upon comparison and observation of the two identification marks m10, m20 could be recognized clearly regardless of illumination environment and observation environment.
Therefore, it is, in practice, preferable that the minor information pattern creating portion 180 sets a closed domain which constitutes the first identification mark m10 so that the width W1 of the first attribute minor domain g1 is at least 5 times greater than the width W2 of the second attribute minor domain g2 and sets a closed domain which constitutes the second identification mark m20 so that the width W2 of the second attribute minor domain g2 is at least 5 times greater than the width W1 of the first attribute minor domain g1 (in the example shown in
Further, in order that brightness of the symbol “protrusion” on observation of a “black protrusion medium” is made equal as much as possible to the brightness of the symbol “recess” on observation of a “black recess medium,” it is preferable that the minor information pattern creating portion 180 sets the width W1 of the first attribute minor domain g1 inside a closed domain which constitutes the first identification mark m1 to be equal to the width W2 of the second attribute minor domain g2 inside a closed domain which constitutes the second identification mark m20 and also sets the width W2 of the second attribute minor domain g2 inside a closed domain which constitutes the first identification mark m10 to be equal to the width W1 of the first attribute minor domain g1 inside a closed domain which constitutes the second identification mark m20.
In other words, in the example shown in
Here, just for reference, dimensional values of individual parts in the identification marks from which favorable observation results were obtained in the experiment performed by the inventor of the application concerned are described as an example. First, inside the part domain p1 shown in
Adoption of the above dimension results in a 2 μm pitch of grid lines in the diffraction grating, and this is a dimension which will cause a sufficient diffraction phenomenon for visible light. Further, in the above-described example, each of the bit figures F recorded at the major recording domain Aα is a square with one side of 0.1 μm, and a difference in depth between a recess structure and a protrusion structure formed on the medium is set to be 0.2 μm.
The first identification mark m10 and the second identification mark m20 formed on an information recording medium are preferably provided in a macroscopically observable size. Of course, even a small mark which is difficult to observe with the naked eye can be observed by using a magnifying glass, etc. In practice, it is preferable that a readout operator who holds a medium is able to recognize immediately whether the medium is a “black protrusion medium” or a “black recess medium” by macroscopically observing the mark. Therefore, it is preferable that the minor information pattern creating portion 180 creates the minor information pattern to such a size that the first identification mark m10 and the second identification mark m20 formed on the information recording medium can be macroscopically observed. In the above-described example, the individual identification marks m10, m20 are set so as to be available in a size of about 3 mm in length and in width on a medium.
Then, a description will be given of several variations of the identification marks used in the present invention.
In executing the present invention, no particular restriction is placed on positions of the first identification mark m10 and the second identification mark m20 on a medium. Therefore, for example, the first identification mark m10 may be arranged at an upper left corner of the medium and the second identification mark m20 may be arranged at a lower right corner thereof. However, it is in practice not very preferable that both of the identification marks are arranged in separation. This is because a readout operator finds it necessary to observe comparatively the two identification marks m10, m20, thereby comparing the degree of brightness. In order that the operator is able to easily observe and compare the identification marks for their brightness, it is preferable that they are arranged so as to be adjacent to each other.
As described in the example shown in
For making observation and comparison easier, it is possible to create a minor information pattern PB in which a closed domain which constitutes the first identification mark and a closed domain which constitutes the second identification mark are in contact with each other.
On the other hand,
In the examples described above, a mark in which a symbol of “protrusion” is designed is used as the first identification mark, and a mark in which a symbol of “recess” is designed is used as the second identification mark. Of course, the identification mark used in executing the present invention shall not be limited to a mark which uses these symbols. The first identification mark is a mark which shows a first method for interpreting data bits recorded at the major recording domain Aα, and the second identification mark is a mark which shows a second method for interpretation. Therefore, any mark may be used as long as a readout operator is able to recognize one of the methods for interpretation on the basis of the identification marks.
For example, a letter “A” may be used as the first identification mark or a letter “B” may be used as the second identification mark. In this case, for example, such an agreement is made that on a medium in which the letter “A” looks brighter, a protrusion is interpreted as a bit “1” and a recess is interpreted as a bit “0” and on a medium in which the letter “B” looks brighter, the protrusion is interpreted as a bit “0” and the recess is interpreted as a bit “1.” And, a readout operator is informed of the agreement, by which the operator is able to recognize a correct method for interpreting data bits by judging the brightness between the letters “A” and “B.”
Of course, the identification mark is not necessarily a symbol indicating “recess” or “protrusion” but may be a mark such as a number, another symbol or a figure. Further, each identification mark is not necessarily constituted with a single closed domain but may be constituted with a plurality of closed domains.
That is, a first identification mark m13 shown in
As described above, where each identification mark is constituted with a plurality of closed domains, a striped pattern shown at the part domain p1 of
Further, the identification mark is not necessarily constituted with a single letter, number, symbol or figure and may be constituted by combining them. For example, a plurality of letters are combined to constitute an identification mark, thus making it possible to constitute an identification mark of a sentence.
Therefore, if the medium prepared on the basis of the drawing pattern P(E) is a “black protrusion medium,” the first identification mark m14 is observed brighter, and if it is a “black recess medium,” the second identification mark m24 is observed brighter. Eventually, a readout operator may perform readout processing in which the protrusion is interpreted as a bit “1” for data bits recorded at the major recording domain Aα, when observing the minor recording domain Aβ of the medium held to find that the sentence of “protrusion is a bit “1”” looks brighter, and may perform readout processing in which the recess is interpreted as a bit “1” when the sentence of “recess is a bit “1”” looks brighter.
In brief, the minor information pattern PB used in the present invention may be available in any pattern, as long as it is provided with a first identification mark having one or a plurality of closed domains for presenting first information which is composed of letters, numbers, symbols, figures or a part of them or a combination of them (information which shows one of two methods for interpreting data bits) and a second identification mark having one or a plurality of closed domains for presenting second information composed of letters, numbers, symbols and figures or a part of them or a combination of them (information which shows the other of the methods for interpretation).
Lastly, another variation of the identification mark which constitutes a minor information pattern is shown by referring to
The minor information pattern shown at an upper part of
Here, the central rectangle m15 constitutes a first identification mark, and a combination of the left-side rectangle m25a and the right-side rectangle m25b constitutes a second identification mark. This variation is characterized in that additionally provided is the lower rectangle m30 which constitutes an auxiliary common identification mark. The auxiliary common identification mark m30 is what-is-called a third identification mark and provided with optical characteristics different from those of the first identification mark and the second identification mark.
At a lower part of
As with the examples described above, a pattern in which a narrow band-like “black domain” and a narrow band-like “white domain” are alternately arranged is formed inside the part domains p1, p2, p3 shown at the lower part of
The enlarged views of the part domains p1, p2 shown in
On the other hand, as for a striped pattern inside the part domain p3 which constitutes the auxiliary common identification mark, in the case of this example, the width W1 of a band which constitutes a “black domain” (the first attribute minor domain g1) is set equal to the width W2 of a band which constitutes a “white domain” (the second attribute minor domain g2). Consequently, the first identification mark is set to give a relationship of W1>W2, the second identification mark is set to give a relationship of W1<W2, and the auxiliary common identification mark is set to give a relationship of W1=W2.
As already described, even where drawing data having the same minor information pattern as shown in
An important point of the example shown in
A role of the auxiliary common identification mark m30 is to constitute a first emblem which shows that the medium concerned is a “black protrusion medium” when simultaneously observed with the first identification mark m15 in the case of the “black protrusion medium” in which the first identification mark m15 is observed brighter than the second identification mark m25 and to constitute a second emblem which shows that the medium concerned is a “black recess medium” when simultaneously observed with the second identification mark m25 in the case of the “black recess medium” in which the second identification mark m25 is observed brighter than the first identification mark m15.
The above role will be described by referring to a specific example shown in
On the other hand,
Finally, in executing the variation shown in
Here, it is important that, inside a closed domain which constitutes the auxiliary common identification mark m30, as the part domain p3 shown in
Further, in the example shown in
An important point is that a difference between the width W1 of the first attribute minor domain g1 and the width W2 of the second attribute minor domain g2 in the auxiliary common identification mark m30 is set smaller than a difference between the width W1 of the first attribute minor domain g1 and the width W2 of the second attribute minor domain g2 in the first identification mark m15 and the second identification mark m25. Where the difference is set as described above, regardless of whether the medium M is actually a “black protrusion medium” or a “black recess medium,” the auxiliary common identification mark m30 is observed intermediate in brightness between the first identification mark m15 and the second identification mark m25. Thus, it is able to play a role as an auxiliary mark to be observed together with either of the media.
The example shown in
Of course, it is theoretically possible to show a method for interpreting data bits without the auxiliary common identification mark m30 by referring to whether the first identification mark (a mark composed of a single square) composed of the central rectangle m15 is observed brighter or the second identification mark (a mark composed of a pair of squares) composed of the left-side rectangle m25a and the right-side rectangle m25b is observed brighter. However, as shown in
It is not always necessary to use the symbol “protrusion” and the symbol “recess” as the first emblem and the second emblem. For example, in
In Section 2, with reference to
In the examples described in Section 7 and Section 8, the patterning device 300 is used to form a physical structure body having a recess and protrusion structure which is composed of a recess C which shows one of the first attribute domain (the first attribute main domain G1 and the first attribute minor domain g1) and the second attribute domain (the second attribute main domain G2 and 25 second attribute minor domain g2) and a protrusion V which shows the other of them. On the other hand, in
The modified example shown in
As described above, the added layer 61 made of a light-reflective material is formed on a surface of a protrusion, by which on comparison between the first identification mark m10 and the second identification mark m20, a difference in brightness between them can be made clearer to provide such an effect that a readout operator can make an observation easily. Each of
At this time, when the added layer 61 made of a light-reflective material is formed on a surface of a protrusion, the light beam L9 made incident on the protrusion can be improved in reflectance to provide an effect that the second identification mark m20 (
Where a medium adopts the structure according to the modified example shown in each of
On the other hand, the modified example shown in
The added layer 66 made of a light-shielding material formed on the back face of the substrate 65 in the structure shown in each of
In any of the examples described above, it is assumed that reflected light which is illumination light irradiated from above on an upper face of the medium having a recess and protrusion structure on the upper face thereof is observed from above, thereby observing each of the identification marks. However, as shown in the example of
In
However, in the constitutions shown in
In the case of the medium shown in
In the case of the medium as well which has adopted the structure according to the modified example shown in
A description has been so far given of some variations in structure of the information recording medium in which a recess and protrusion structure is formed on the surface of the substrate. In executing the present invention, the physical structure which shows bit information shall not be necessarily limited to a recess and protrusion structure but there may be adopted a network structure which is shown in
In this case, individual data bits of the digital data to be stored are recorded as a network structure composed of a through hole H which shows one of a bit “1” and a bit “0” and a non-hole part N which shows the other of them at a major recording domain Pa. For example, in the network structure body 12 shown in
On the other hand, the information which shows a method for interpreting data bits is recorded at a minor recording domain P6 as information of the pair of identification marks.
Therefore, the first identification mark m10 (
That is, in the example shown in
On the other hand, the modified example which is shown in
As described above, where the added layer 71 made of a light-reflective material is formed on an upper face of a non-hole part N to compare the first identification mark m10 with the second identification mark m20, a difference in brightness between them can be made clearer to obtain an effect that will facilitate the observation by an readout operator. That is, when the added layer 71 is formed, the light beam L15 made incident on a through hole H is not observed above, either. However, the light beam L14 made incident on a non-hole part N can be improved in reflectance to obtain an effect that both of the identification marks are allowed to look brighter. Then, a readout operator is able to make a comparison and observation more easily.
A description has been so far given on the assumption that reflected light which is illumination light irradiated from above on the upper face of the medium composed of a network structure body is observed from above, thereby observing individual identification marks. In the case of the medium composed of a network structure body, transmitted light from the upper face of the medium which is illumination light irradiated from below on the lower face thereof is observed from above, thus making it also possible to recognize individual identification marks.
Since the substrate 70 is constituted with a non-translucent material, a light beam L17 made incident on a non-hole part N from below is prevented from upward transmission. However, a light beam L16 made incident on a through hole H is partially transmitted above and observed (Of course, some light collides with a side wall of a through hole H, scatters and disappears). Therefore, in the case of the example shown in the drawing, the first identification mark m10 (
The modified example shown in
In the case of the medium shown in
A description has been so far given of some variations of a structure of the information recording medium. It should be noted that where reflection observation is made on the assumption that reflected light on the upper face of the medium which is illumination light irradiated from above the medium is observed from above and where transmission observation is made on the assumption that transmitted light from the upper face thereof which is illumination light irradiated on the lower face thereof from below is observed from above, a relationship of brightness and darkness between the identification marks will be reversed.
For example, the medium shown in
Similarly, the medium shown in
In reality, at the time when the storage processing computer 100′ is used to prepare the drawing data E, it is impossible to estimate what kind of variation of the medium is finally prepared by the patterning device 300. Therefore, in practice, as information showing a method for interpreting data bits shown by each of the identification marks m10, m20, in principle, the information is recorded on the assumption that reflection observation is made, and an arrangement may be made so that the method for interpreting data bits is reversed where a readout operator compares the identification marks m10, m20 by transmission observation.
Specific materials for constituting the above-described individual added layers are those described in Section 2. For example, light-reflective materials include metals such as aluminum, nickel, titanium, silver, chromium, silicon, molybdenum and platinum as well as alloys, oxides and nitride of the metals. Light-shielding materials include materials composed of compounds such as oxides and nitrides of metals. Of course, as described in Section 2, in place of forming another layer having a clear border surface like an added layer, impurities can be doped on a surface on which an added layer is to be formed, thereby obtaining a similar effect.
Lastly, a description will be given of processing procedures in which the technique for recording the identification marks described in Section 7 to Section 10 is understood as a process invention of the information storage process by referring to the flowchart shown in
First, in Step S31, a data input step is executed for inputting digital data D to be stored. Processing details of this step are the same as the processing details of Step S11 in the basic embodiment shown in
Then, in Step S32, there is executed a main information pattern creating step which creates a main information pattern Pα showing information of individual data bits which constitute the digital data D input in Step S31. Processing details of this step are the same as the processing details of Step S12 to Step S15 in the basic embodiment shown in
Here, it is important that the main information pattern Pα created by the main information pattern creating step is, as shown inside the part domain p3 in
On the other hand, in Step S33, there is executed a minor information pattern creating step which creates a minor information pattern PB showing a method for interpreting data bits shown by the main information pattern Pa. The step is a new step which is not found in the basic embodiment, and the specific processing details have already been described as processing functions of the minor information pattern creating portion 180.
Here, it is important that, as shown in
Moreover, as shown inside the part domain p in
Here, it is also important that the closed domain which constitutes the first identification mark m10 is characterized in that the width W1 of the first attribute minor domain g1 is set so as to be greater than the width W2 of the second attribute minor domain g2 and the closed domain which constitutes the second identification mark m20 is characterized in that the width W2 of the second attribute minor domain g2 is greater than the width W1 of the first attribute minor domain g1.
Then, in Step S34, there is executed a drawing data creating step which creates drawing data E for drawing the main information pattern Pα and the minor information pattern P6. Processing details thereof are substantially the same as the processing details of Step S16 in the basic embodiment shown in
Here, the drawing data E created in the drawing data creating step is drawing data by which a first attribute main domain G1 and a first attribute minor domain g1 are exposed but a second attribute main domain G2 or a second attribute minor domain g2 is not exposed. Alternatively, the drawing data is drawing data by which the second attribute main domain G2 and the second attribute minor domain g2 are exposed but the first attribute main domain G1 or the first attribute minor domain g1 is not exposed. Moreover, the drawing data E is set to such a dimension that the width of the first attribute minor domain g1 and that of the second attribute minor domain g2 are sufficient in constituting a diffraction grating for visible light.
Subsequently, in Step S35, there is executed a beam exposure step in which on the basis of the drawing data E created in Step S34, beam exposure is performed by using electron beams or laser light on a substrate which acts as an information recording medium. Processing details of the step are the same as the processing details of Step S17 in the basic embodiment shown in
In Step S36 which is the last step, there is performed a patterning step in which pattern processing is performed on the exposed substrate, thereby creating the information recording medium in which a physically structured pattern is formed according to the drawing data E. The processing details of the step are the same as the processing details of Step S18 in the basic embodiment shown in
The information storage device and the information readout device according to the present invention are able to record various digital data into media and also read out the data and, therefore, can be used for performing recording of various types of information in industries. Of course, since beam exposure processing and pattern processing are needed at the time of storage of data, these devices are not suitable for an application where data is read and written frequently. However, the devices are able to perform highly integrated recording of information in a medium which is expected to have durability for a long time of several hundred to several thousand years. Therefore, they can be used in storing information such as public documents which are to be stored for a long time, as with ancient stone monuments and stone plates.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2015/077000 | 9/15/2015 | WO | 00 |
