Patent Application
20070165512
This application claims the foreign priority benefit under Title 35, United States Code, § 119 (a)-(d), of Japanese Patent Application No. 2005-373921, filed on Dec. 27, 2005 in the Japan Patent Office, the disclosure of which is herein incorporated by reference in its entirety.
This invention relates to information processing apparatuses, and more particularly to a microminiaturized storage device for information recording, which is capable of recording an enormous volume of electronic data (as information) at high speed and at an extremely high density.
The information processing system using a computer as a key device have rapidly become pervasive in various fields of application, ranging from systems for information communications network, as typified by the Internet and local area networks or LANs, to those for use in household appliances and automobiles, which have become prevailing recently. Most of such systems need to have storage devices for storing electronic information temporarily or semipermanently therein. Thus, as the volume of electronic information to be handled in the systems increases, microminiaturized, fast and high-capacity storage devices are in increasing demand year by year.
Conventional information storage technologies have provided two dominant recording schemes: magnetic recording and optical recording; it has however been shown that the both schemes are approaching their limits of capacity. That is, the magnetic recording has its capacity limit imposed by the volume limit of magnetic material required for magnetization reversal mechanism using magnetic field, and the optical recording has its capacity limit imposed by the diffraction limit of light. Thus, the recording density cannot be increased beyond its intrinsic capacity limit for either scheme. Particularly, for the magnetic recording, the increase in areal or surface recording density, which has set records yearly up by one hundred percent since the giant magnetoresistive (GMR) head technology was brought into practical use, appears to suffer an inevitable slowdown.
Probe storage technology is a storage technology proposing an alternative recording scheme which is expected to overstep the limits imposed in the aforementioned conventional schemes. The probe storage technology proposes several methods, which include: a method of applying the principle of a scanning probe microscope (hereinafter referred to as “SPM”) to near-field scanning of an object through a microminiature probe tip for detecting a physical quantity with a spatial resolution at an atomic or molecular level; a method of utilizing the quantum effect of substances from an ultimate single atom that is used as an information recording unit; and a microminiature mechanical recording method utilizing a probe structure.
The method of applying the principle of SPM has been proposed for example in U.S. Pat. No. 5,808,977, which discloses a method of recording and detecting a magnetic domain structure through a probe tip on the principle of the magnetic force microscope (hereinafter referred to as “MFM”). This method is one prospective recording method for achieving high-density recording, by detecting displacements of a probe tip, which is caused by a magnetic force the probe tip made of magnetic material receives when the probe tip is moved across a magnetic domain recorded on a magnetic recording medium.
The mechanical recording method utilizing a probe structure has been proposed for example in Vettiger, P.; Cross, G.; Despont, M.; Drechsler, U.; Durig, U.; Gotsmann, B.; Haberle, W.; Lantz, M. A.; Rothuizen, H. E.; Stutz, R.; Binnig, G. K., ‘The “millipede”—nanotechnology entering data storage’, IEEE Transactions on Nanotechnology Vol. 1, Issue 1, March 2002, pp 39-55 or U.S. Pat. No. 5,835,477, which discloses a method of recording information by pressing a probe tip heated to and maintained constant at a specific temperature, onto a recording medium made of resinous material to form minute pits. This method provides a cantilever array component in which a number of cantilevers each having a probe element (probe tip) disposed at its tip are arranged in such a manner that a plurality of probe tips are opposed to a medium, so that each one of the probe tips is configured to record information onto one specific area (pixel) corresponding thereto of the medium independently and thus the plurality of probe tips can record pixels in parallel. The cantilever array component as used in this method has a substantially complete set of specific components of a storage device, and is expected to achieve improved data transfer rate due to its parallel processing capability and improved recording density due to its miniaturized probe structure.
Another example of the mechanical recording method utilizing a probe structure is proposed for example in JP 10-40597 A, which discloses a memory device including a cantilever array component, a recording medium component and an actuator, which are each laminated on a substrate and joined together in layers, wherein the distance between a probe and a medium are regulated by a suction electrode.
In the conventional technology as disclosed in U.S. Pat. No. 5,808,977, there remain several technical challenges to be addressed, for example, in a magnetic field generation mechanism for applying a magnetic field strong enough to write information on a magnetic recording medium through the probe tip made of magnetic material, an actuator for keeping a small gap between the probe tip and the magnetic recording medium at a certain distance, and a contrivance for increasing a data transfer rate in an information reading/writing operation. Therefore, variations in distance of the gap between the probe tip and the magnetic recording medium inevitably involved in the information reading/writing operation would disadvantageously make it difficult to ensure signal integrity as represented by a signal-to-noise ratio and a recording error rate.
In the conventional technology as disclosed in IEEE Transactions on Nanotechnology Vol. 1, Issue 1, March 2002, pp 39-55 or U.S. Pat. No. 5,835,477, the medium is supported on a column made of flexible resins for the purpose of ensuring positioning accuracy of the medium actuated by the actuator; therefore, the resinous material of the column functions as a damper when the medium is actuated, which would resultantly lower the resonant frequency, thus making it difficult to increase the data transfer rate. In order to clear up the difficulty, in this example, a multi-probe parallel processing using a large-scale integrated cantilever array structure in which a great number of probe-tipped cantilevers are concentrated in a small area is adopted to increase the data transfer rate. As a result, the cantilever array component has voluminous and complex wiring with lots of diode switches installed, which would cause other problems, such as attenuation of high-frequency signals due to the inter-wire capacitance and a bit loss due to the limited manufacturing yield.
In the conventional technology as disclosed JP 10-40597 A, the recording medium component is supported by a member made of the same material Si as used in the substrate, so that the aforementioned factor affecting the resonant frequency has been removed already; however, there still remains a matter to be addressed therein. To be more specific, it is to be noted that no consideration is given to maintaining a fixed distance of the small gap between the probe tip and the medium. Therefore, changes in the gap may become nonnegligible because of an impact applied to the device or disturbances which may occur depending upon the position/orientation of the device installed in a mobile gear held by a user. Such nonnegligible changes in the gap would disadvantageously become a factor of errors in the information reading/writing operation.
Illustrative, non-limiting embodiments of the present invention overcome the above disadvantages and other disadvantages not described above. Also, the present invention is not required to overcome the disadvantages described above, and an illustrative, non-limiting embodiment of the present invention may not overcome any of the problems described above.
It is an aspect of the present invention to provide an information processing apparatus for recording information on an information recording medium. To record information on the information recording medium, a probe tip is configured to approach a recordable area allocated on the information recording medium and to effect a local change of state in the recordable area.
In an exemplary embodiment, the information processing apparatus comprises a cantilever array component, a medium component, and a fixed electrode or magnetic pole component, wherein the medium component is disposed between the cantilever array component and the fixed electrode or magnetic pole component. In the cantilever array component, an array of at least one cantilever is installed. The at least one cantilever comprises a probe tip configured as described above. The medium component has a fixed portion and a movable portion, and the information recording medium is installed in the movable portion. The fixed electrode or magnetic pole component is configured to actuate the medium component, i.e., to move the movable portion of the medium component relative to the cantilever array component. The medium component comprises a plurality of first electrodes or magnetic poles that are arranged at three or more spots of the movable portion and configured to support by servo control the information recording medium relative to the array of the at least one cantilever with a gap kept constant between the information recording medium and the array of the at least one cantilever, while allowing the information recording medium to move in two directions X and Y substantially perpendicular to each other, within an X-Y plane substantially parallel to the array of the at least one cantilever. Each of the cantilever array component and the fixed electrode or magnetic pole component comprises a plurality of second electrodes or magnetic poles configured to repel or attract the plurality of first electrode or magnetic poles. The plurality of second electrodes or magnetic poles are significantly different in size in a plane parallel to the X-Y plane from the plurality of first electrodes or magnetic poles.
In another exemplary embodiment, the information processing apparatus comprises a cantilever array component, a medium component, and a fixed electrode or magnetic pole component, wherein the cantilever array component is disposed between the medium component and the fixed electrode or magnetic pole component. The cantilever array component has a fixed portion and a movable portion, and an array of at least one cantilever is installed in the movable portion. The at least one cantilever comprises a probe tip configured as described above. In the medium component, the information recording medium is installed. The fixed electrode or magnetic pole component is configured to actuate the cantilever array component, i.e., to move the movable portion of the cantilever array component relative to the medium component. The cantilever array component comprises a plurality of first electrodes or magnetic poles that are arranged at three or more spots of the movable portion and configured to support the array of the at least one cantilever relative to the information recording medium with a gap kept constant between the array of the at least one cantilever and the information recording medium, while allowing the array of the at least one cantilever to move in two directions X and Y substantially perpendicular to each other, within an X-Y plane substantially parallel to the information recording medium. Each of the medium component and the fixed electrode or magnetic pole component comprises a plurality of second electrodes or magnetic poles configured to repel or attract the plurality of first electrode or magnetic poles. The plurality of second electrodes or magnetic poles in a plane parallel to the X-Y plane are significantly different in size in a plane parallel to the X-Y plane from the first electrodes or magnetic poles.
With the above embodiments, the tendency toward decrease in resonant frequency can be repressed, so that the data transfer rate can be increased. Further, a gap between a probe tip and a medium can be maintained constant at a short distance, and thus the aforementioned factor of errors in the information reading/writing operation as induced by an impact applied to the device or disturbances which may occur depending upon the position/orientation of the device installed in a mobile gear held by a user can be removed effectively.
In the information processing apparatus as implemented according to the above embodiments, the plurality of first electrodes or magnetic poles may comprise electromagnetic coils or permanent magnets having directions of magnetization substantially perpendicular to the X-Y plane, and the plurality of second electrodes or magnetic poles may comprise electromagnetic coils or permanent magnets having directions of magnetization that are the same as or opposite to the directions of magnetization of the plurality of first electrodes or magnetic poles. This is one of the simplest constructions achieved easily by a thin-film forming process without sacrificing the advantages that may be derived from the inventive features of the present embodiments.
Alternatively or additionally, in the information processing apparatus as implemented according to the above embodiments, the plurality of first electrodes or magnetic poles may comprise electromagnetic coils or permanent magnets having directions of magnetization substantially parallel to the X-Y plane, while the directions of magnetization of adjacent first electrodes or magnetic poles are substantially perpendicular to each other in the X-Y plane; and the plurality of second electrodes or magnetic poles may comprise electromagnetic coils or permanent magnets having directions of magnetization that are the same as the directions of magnetization of the plurality of first electrodes or magnetic poles. This construction may be preferable in particular applications because the necessity for installing many electromagnetic coils or the like in the movable portion can be obviated so that the advantages that may be derived from the inventive features of the present embodiments can be obtained without causing the increase in temperature of the movable portion and surrounding components.
The probe storage system configuration as proposed above may be able to achieve the following advantages. Oscillations in direction Z which are likely to occur when an actuator moves the movable portion in directions within X-Y plane can be controlled to the limit not exceeding a permissible level, and thus the bandwidth for servo control can be raised. Accordingly, the decrease in data transfer rate, which would cause significant problems especially in a mass storage system, can be prevented, with the result that a high-speed/quick-response storage device can be provided. Moreover, the distance between the probe tip and the information recording medium can be maintained with high precision, and thus the signal-to-noise ratio in the information reading/writing operation can be improved. Further, even under conditions where an impact applied to the device or disturbances which may occur depending upon the position/orientation of the device installed in a mobile gear held by a user would possibly be received, the recording error rate can be reduced effectively. Consequently, a large-capacity storage device suitable for use in mobile computing devices can be provided.
Other advantages and further features of the present invention will become readily apparent from the following description of exemplary embodiments with reference to accompanying drawings.
A detailed description will be given of the exemplary embodiments of the present invention in comparison with a conventional apparatus, with reference to the accompanying drawings.
Referring now to
In this arrangement, when a voltage is applied between the fixed electrode and the moving electrode, an electric field generated by this voltage urges the movable portion of the medium component 2 to move. However, since the supporting springs 21 places a constraint on movement of the movable portion of the medium component 2 in vertical direction (direction Z), the movable portion of the medium component 2 is shifted mostly in horizontal directions (directions X and Y parallel to an X-Y plane) but only slightly in the direction Z. When electronic information is written on the medium 20, a voltage is applied to a selected probe tip, and at the same time a voltage is applied to the suction electrode 13 as well so that the movable portion of the medium component 2 is actuated to move slightly in the direction Z toward the cantilever array 10 of the cantilever array component 1. Thus, the selected probe tip is pushed to the recordable area of the medium 20 provided in the movable portion of the medium component 2, to change dielectric characteristics of a portion of the medium 20 with which the probe tip is brought into contact.
In the illustrated conventional example, as described above, no consideration is given to the necessity of maintaining a small gap between each of the probe tips in array and the medium at a certain distance, and thus there remains the problem that changes in the gap, which may be caused by an impact applied to the device or disturbances which may occur depending upon the position/orientation of the device installed in a mobile gear held by a user, would possibly become a factor of errors in the information reading/writing operation. Moreover, since the movement in directions X and Y (a direction parallel to the plane X-Y) and the suction in the direction Z are not regulated independently, it would disadvantageously be necessary to provide a complicate control system for constantly canceling interference of the two regulations.
As shown in
Details of the assembly unit as the first exemplary embodiment of the present invention will now be described with reference to
Operation of the supporting electrodes or magnetic poles 23 in the first exemplary embodiment of the present invention will now be described with reference to
Next, the principle on which the moving electromagnetic coil 27 and the fixed permanent magnet 36 produce an actuating force in directions X, Y (direction parallel to the plane X-Y) according to the first exemplary embodiment of the present invention will be described with reference to
Supporting electrodes or magnetic poles 232, 233 located at four corners of the movable portion of the medium component 2 and the fixed electrode or magnetic pole component 3, respectively, produce repulsive forces between opposed electrodes or magnetic poles 232 and 233, and serve to support the medium 20 suspended in balance so that the medium 20 may not wobble in the direction Z. The four moving side supporting electrodes or magnetic poles 232 are maintained at the same potential (preferably including the ground potential, but not limited thereto), while the four fixed side supporting electrodes or magnetic poles 233 are maintained at individual potentials, respectively, and a detector for measuring a counter electromotive force at each position is connected to each supporting electrode or magnetic pole 233. In this condition, the electric current applied to the fixed side supporting electrodes or magnetic poles 233 are regulated by servo control so that a deviation in the counter electromotive force is minimized which would otherwise appear due to slight wobbling in direction Z accompanied with an operation of the actuator moving the medium 20 in directions X and Y (direction parallel to the plane X-Y).
The moving side supporting electrode or magnetic pole 232 is designed to be smaller than the fixed side supporting electrode or magnetic pole 233 so that overlapping areas of opposite faces of the fixed side and moving side supporting electrodes or magnetic poles will not change even if the positions of the moving side supporting electrode or magnetic poles are shifted in directions X and Y (direction parallel to the plane X-Y) when the medium 20 is moved in directions X and Y. This setup serves to prevent variations in the electromagnetic force which would be caused by actuation of the medium 20 in directions X and Y, and therefore enables mutually independent control over movement of directions X and Y and support in direction Z.
In the actuator according to the second exemplary embodiment, the balance in direction Z is maintained by servo control, and constraint with damper action as adopted in the column made of resinous material in the conventional example is not applied; therefore, a high resonant frequency can be maintained when the medium is actuated in directions X and Y, and fast actuation becomes possible as a result. Further, the medium is supported in such a manner as to reduce wobbling in direction Z, and thus the gap between the probe tip and the medium can be kept constant at a certain distance, which increases the recording density and the signal-to-noise ratio, to thereby make the recording error rate lower.
An overall structure of an alternative information processing apparatus using a probe according to a fourth exemplary embodiment of the present invention is shown in
An example of arrangement of an alternative information processing apparatus using a probe according to a fifth exemplary embodiment of the present invention is shown in
An example of arrangement of an alternative information processing apparatus using a probe according to a sixth embodiment of the present invention is shown in
Some examples of actuator supporting spring structures applicable to any of the illustrated exemplary embodiments are taken up for discussion with reference to
Supporting springs 211 as shown in
Supporting springs 212 as shown in
Supporting springs 213 as shown in
In any of the above structures, a large aspect ratio structure (see examples of dimensions indicated in the drawing figures) may preferably but not necessarily be adopted such that the beam thickness relative to the beam width is large enough, because the larger aspect ratio of the supporting springs would reduce wobbling of the medium 20 in direction Z.
Relative positional relationships between the cantilever array 10 and recordable areas (pixels) 25 allocated in the medium 20, which are applicable to any of the above exemplary embodiments, are illustrated in
As shown in
The next discussion focuses on details of a recording medium 20 taken by way of example, which may be applicable to any of the illustrated exemplary embodiments. An example of the recording medium 20 is illustrated in
As shown in
According to the exemplified embodiments as described above, the probe tip 11 is controlled so as not to come in contact with the surface of the recording dot 24, and thus no mechanical abrasion would occur. Therefore, the apparatus consistent with the present invention with the long-life information recording medium and cantilever array incorporated therein can be used for a long time.
The information processing apparatus using a probe according to the illustrated exemplified embodiments of the present invention can furnish a solution to a conventional problem of reduced data transfer rate which is critical in mass storage systems, and can provide a high-speed/quick-response storage device. Moreover, the dimensions of the positioning mechanism can be reduced, and the storage device can be downsized in its entirety. Further, irrespective of impacts or disturbances which would become a significant problem in the use of the mobile/portable devices, the signal-to-noise ratio can be maintained during a writing/reading operation. Consequently, a mass storage device with which the recording error rate is reduced effectively can be provided.
According to the present invention, a storage device or memory unit that is packed in a volume smaller than a magnetic disc drive and capable of storing a large volume of data, achieving a recording capacity larger than the existing flash memory can be provided. Since the storage device implemented according to the present invention can realize recording of extremely large volume of information in a small volume equivalent to the flash memory, it is suitable for applications to microminiature mobile information processing terminals such as a video camera, a notebook personal computer, personal digital assistant and a cellular phone. Further, due to its fast operation speed, the information processing device consistent with the present invention may find application in external storage devices for a server that requires large-scale storage as a preferred embodiment of the present invention, and is expected to replace magnetic disc drives.
It is contemplated that numerous modifications may be made to the exemplary embodiments of the invention without departing from the spirit and scope of the embodiments of the present invention as defined in the following claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| JP2005-373921 | Dec 2005 | JP | national |
