This invention relates to a system and method for accessing media in a data storage system, and in particular to, a system and method for accessing holographic data storage media in a holographic data storage system in which the media can be partially or fully removed from a cartridge for presentation to an optical system for holographic read and/or write operations, and the holographic media is returned back in the cartridge after operating on the media. In read/write holographic data storage systems, the invention is especially useful in that the holographic media is at all times in light-tight conditions when in the cartridge, or in the data storage system accessing the cartridge, such that the media is not subject to external light to which the media is sensitive. The cartridge may also be used in read only holographic data storage systems, where the cartridge and environment of the system need not be light tight.
In conventional disk-based data storage devices, the pick-up head for the device generally moves such that the pick-up head can track different radial positions of the data storage media. This is true for optical disks, such as compact disks (CD) and digital video disks (DVD), and magnetic disks, such as fixed and removable hard disks and floppy disks. In these disk-based data storage systems, while the pick-up head can be moving or stationary in a radial direction of the disk, the disk is also spinning, thereby enabling the optical pick-up head access to the complete area of the data storage media.
Holographic data storage systems (HDSS) enable storage of larger amount of data than possible on a CD, DVD, or magnetic disk. An example of an HDSS is shown in U.S. Pat. No. 5,621,549, which describes the actuating of a holographic storage media along a single linear direction in the plane of the surface of the holographic storage media to access different areas of the storage media for reading and writing on the media. Prior to recording information on holographic media, exposure of the media to light negatively affects the ability to record information on the media. Further, once recorded upon, unrecorded areas of the media remain sensitive to the exposure to light. Optical disks of CD or DVD formats are different from holographic media in that their recordability is not affected by exposure to light, and CD or DVD drives utilize non-holographic methods for reading and/or writing data. Conventional magnetic disks, such as floppy disks, are also not affected by light, and like optical disks, do not require packaging or drive mechanisms that prevent light from reaching their recordable surfaces.
U.S. Pat. No. 5,526,337 describes a package or cartridge that houses a holographic media storage disk. The package is made of opaque material, is light-tight, and has a data window allowing access to the holographic media by a HDSS, and the data window has a sealing mechanism by which the holographic media can be sealed from light when the media is not being accessed. The package may further have a locking mechanism for preventing the data window from being accessed without a proper unlocking mechanism.
Prior art approaches for packaging for data storage media also include packages sold by Sony Corp. of Japan and SyQuest Technology, Inc. of CA, U.S.A. For example, in the Sony Blu-ray disk cartridge, a data window shutter system is provided having a component with a circular boundary that has grooved teeth towards the edge of the cartridge boundary. These teeth form a gear that is accessed by a motor external to the cartridge. By actuating this geared component of the shutter system, one causes other components of the shutter to move and rotate in such a way that a longitudinal slot along a substantially radial position along the disk to open up on the bottom of the cartridge, allowing access to radial areas of the blu-ray DVD disk contained within. In the SyQuest Sparq removable hard disk package, a rotary aperture at the front of the package is slid open along a trail by a mechanical motor motion that pulls on a tab at one end of the rotary aperture. In this manner, the Sparq cartridge allows the magnetic pick-up head of the drive to access inside of the cartridge and the magnetic disk media contained within. In neither of these Sony or SyQuest packages, nor in the package of U.S. Pat. No. 5,526,337, is capability provided for allowing for the data storage media contained within their respective packages or cartridges to be locatable for actuation outside of the boundaries of the cartridge in a data drive system.
It is an object of the present invention to provide an improved data storage system for accessing media contained in cartridges which enables actuation, e.g., read/write, upon the media outside the boundaries of the cartridge.
It is a further object of the present invention to provide an improved data storage system for accessing media contained in cartridges in which the system can engage the media in each cartridge and then position the media partially or fully outside the cartridge.
It is another object of the present invention to provide an improved data storage cartridges for holographic data storage media having a normally closed window which is opened in a holographic data system (or drive) to enable at least part of the media in the cartridge be moved and positioned with respect to holographic read/write optics with respect to different locations on the media, and returning such media to the cartridge and closing the window prior to ejecting the cartridge from the holographic data storage system.
It is another object of the present invention to provide an improved data storage cartridges having read/write holographic data storage media in which each cartridge prevents external light sensitive to the media from reaching the media while enabling the media in the cartridges to be partially or fully removable to enable actuation by a data storage system outside the cartridge.
Briefly described, a holographic data storage system (HDSS) embodying the present invention has one or more cartridges having data storage media, a window, and a shutter closing the window, in which the shutter is externally engagable to open the window, and a housing having an optical system for at least one of reading, writing, or reading and writing data on data storage media. The housing has an aperture through which one of the cartridges is partially or fully received, and a motor driven gear that engages a track along the shutter to move the shutter to open the window of the cartridge, and a positioning mechanism which engages the media through one of the window or another opening or slot in the cartridge, and moves the media partially or fully from the cartridge through the window to present the media to the optical system. After operating on the media, the positioning mechanism moves the media back into the cartridge through the window prior to disengaging from the media, and then the shutter is closed over the window prior to ejecting the cartridge from the system.
At all times the media is prevented from being exposed to light external in the housing of the system or the cartridge. However, in read-only media where the optical system enables only read operations to take place, the cartridge and housing need not be light-tight, since holographic media exposure to external light does not affect read-only media or read-only holographic operations.
In one example of the cartridge, the media may be in a disk format and each cartridge has a chamber having a cylindrical wall with the window, and the shutter is rotatable along the interior of this wall to open and close the window. A slot (or opening) is provided in another wall for accessing the hub of the media. A pivotal hub cover is provided, such that the hub cover and part of the shutter closes the slot, and rotation of hub cover is coupled to rotation of the shutter to open and close the slot. When the window and slot are open, the media is engagable upon the positioning mechanism through the opening to the hub of the disk, and the slot is of sufficient size to enable the positioning mechanism to move at least a part of the media through the opened window outside the boundaries of the cartridge. The positioning mechanism may be provided by a translation stage and a rotatable stage mounted to the translation stage. The spindle of the rotory stage is positioned for coupling to the hub of the media, and then the translation stage moves in a direction through the slot of the cartridge to at least partially remove the media from the cartridge, or in a reverse direction through the opening of the cartridge to return the media to the cartridge. When the media is returned into the cartridge, the spindle disengages from the hub of the media, the shutter and hub cover closes the window and slot, respectively, and the cartridge may be ejected from the housing.
In another example of the cartridge, the media in the cartridge may be in a rectangular card format, in which the positioning mechanism is provided by linear motors (or stages) which are coupled to the sides of the card to partially or fully remove the card for presentation to the optical system, and then returning the card to within the cartridge. A shutter mechanism, e.g., door, is opened or closed to enable access to the card by the positioning mechanism.
The aperture of the housing may have one or more light blocking members for preventing light from entering the housing after the cartridge passes partially or fully through the aperture.
A method is also provided having the steps of: providing a housing having an optical system for at least one of reading, writing, or reading and writing data on holographic data storage media; receiving a cartridge fully or partially through an aperture in the housing; removing the media partially or fully from the cartridge received in the housing to present the media to the optics; and inserting the media back into the cartridge after presentation to the optics. Where the cartridge has a window which is normally closed when the cartridge is outside the housing, the removing step further provides for opening the window, and positioning the media partially or fully from the cartridge through the opened window to present the media to the optics.
One advantage of the system and method is that by having a cartridge wherein a portion of it opens to allow a data storage media to be actuated outside of said cartridge can provide a lighter mass for the HDSS to servo than if the HDSS needed to servo both the cartridge and the media inside. Another advantage is that by actuating only the media and not the cartridge and media that for a HDSS that has two opposing read and write optical modules that the opposing elements or fixtures of each module can be brought closer together since only the media needs to clear the gap between the modules and not a thicker cartridge.
Although the system, method, and cartridge are described below for use with holographic optical systems and media, they may be used in other non-holographic data storage systems (e.g., optical magnetic, or combined optical magnetic read/write systems).
The foregoing objects, features and advantages of the invention will become more apparent from a reading of the following description in connection with the accompanying drawings, in which:
Referring to
Media 4 represents holographic recordable material, such as available from Aprilis, Inc., of Maynard, Mass., U.S.A. The media may be in various forms, such as a disc, planar card, or other shapes, such that holographic recordings may be made in the volume of the media. For purposes of illustrating the invention, the media is described as being a disc having a centrally attached hub 8. The housing 1 may have a cartridge loader mechanism similar to other cartridge loader mechanisms of other types of data drives for pulling in and positioning a cartridge, and ejecting a cartridge, such as used in drives with earlier mentioned cartridges from Sony Corp. or SyQuest, but provides for partially or fully loading the cartridge prior to opening a cartridge window.
Cartridge 3 represents a light-tight housing which blocks external light from entering the cartridge, as such, the cartridge may be made of plastic material non-transmissive of light and/or having light blocking coatings on surfaces to prevent light from reaching the media when within the cartridge, or only allows light of a wavelength the holographic media is not sensitive to. The cartridge 3 has a window (or opening) 105 extending along side wall 3a of the cartridge sized to provide an aperture through which all or part of the media can be removed from the cartridge, as illustrated in
When the cartridge is inserted into housing 1 via aperture 2, the movement of the cartridge 3 in the z direction (as indicated by arrow 10a) trips a contact 104a (e.g., an optical or mechanical switch) that relays a signal to a motor operating gear 104 (or to a programmed computer system which sends control signals to the motor of gear 104) to open the shutter mechanism 106. The motor driven gear 104 engages a gear rack 55 of the shutter mechanism 106 which rotates shutter mechanism 106 in a first direction to open window 105, or later prior to ejection of the cartridge in the reverse direction to close window 105 (
A positioning mechanism in housing 1 engages media 4 after window 105 is opened. The positioning mechanism includes a translation stage 10 and a rotary spindle 6 attached to a rotary motor mounted upon the translation stage. The rotary spindle 6 has a chuck 7 which can be positioned to engage the media, thereby attaching the media 4 to the positioning mechanism. The translation stage 10 is movable bi-directional along the z axis as indicated by arrow 10a, but may also be movable along the x and y axes. The chuck 7 thus can gain access to the hub 8 of the media 4 through slot 45. The spindle 6 moves upwards to engage the hub 8 of the media and/or the media drops down to engage onto the spindle 6, as will be described later in more detail. The chuck 7 engages the media 4 by one of mechanically coupling, magnetic attraction, or combination thereof, such that the media 4 is movable by the positioning mechanism. Once in engagement upon the spindle 6, the translation stage 10 by moving the spindle 6 along slot 45 moves all or part of the media 4 out of the cartridge through the window 105 for presentation to a holographic optical system for reading and/or writing operations on the media. The translation stage 10 in combination with rotation of the media upon spindle 6 enables positioning of media 4 at one or more locations with respect to such optical system. In this manner, means are provided by which the holographic media is removed from the cartridge and servo'd in front of the optical elements that serve as the write and/or read optical modules for the HDSS. Unlike prior art data storage media, a portion or all of the holographic media can thus be actuated outside the boundaries of the cartridge.
As stated earlier, the chuck 7 engages (or attaches to) the hub 8 of media 4 that include lowering the cartridge 3 such that the hub meets the chuck, by raising the rotary motor 5 such that the chuck meets the hub, or a combination of these two motions. For example, the cartridge loader, while in the process of loading the cartridge into the HDSS, can move the cartridge 3 in the z direction but then drop the height of the cartridge (down in the y direction) such that the hub 8 of the holographic media 4 contained within the cartridge 3 meets the chuck 7 of the rotary spindle 6, as typically performed in non-holographic data storage devices, such as magneto-optical drives and floppy disk drives. In another example, the rotary spindle 6 and the chuck 7 can rise up to make contact with the hub 8 of the holographic media 4 as typical of non-holographic data storage systems, such as CD and DVD drives on desktop computers.
The attachment of the hub 8 and the chuck 7 may be accomplished by magnetic means. For example, either the hub 8 or the chuck 7 is made from a magnetic material such as 400 series stainless steel or any other magnetic steel or metal, which if it is not corrosion resistant is provided with a suitable coating. The remaining mating component houses a magnet in order to create the magnetic attraction of the two components. Such attachment of the hub 8 and chuck 7 may be similar to that used in typical magneto-optical drives, wherein the hub of a magneto-optical disk is made from stainless steel and the chuck of the rotary spindle contains at least one magnetic component.
Alternatively, the hub 8 and the chuck 7 may be mechanically attached. For example, a cartridge containing the holographic media can be loaded into the drive and once the cartridge is fully loaded, the spindle 6 can rise up to meet the hub of the holographic media. The spindle 6 can contain a mechanical chuck that through the use of springs and clasps, can grab the hub 8 of the holographic media 4 with sufficient force so that the media can be servo'd in position in accordance with the specification of the HDSS. In the case of a mechanical attachment of the rotary spindle 6 to the holographic media 4, the hub 8 does not require to be bonded, or otherwise attached, to the holographic media. Instead, a through hole may be provided in the media, such as in the center thereof, that the mechanical chuck of the rotary spindle 6 can attach itself to. Such engagement may be similar to engagement of a spindle to an optical disk in DVD/CD players in desktop personal computers. Optionally, chucks and hubs with key devices of U.S. Pat. No. 5,883,880 may also be used to enable self-referencing to each other.
Optionally, the window 105 of the cartridge can be opened and closed by harnessing the mechanical energy of the cartridge loader that loads the cartridge in and out of the HDSS, and through the use of the motor operating gear 104 that opens the window 105 separately from the motion of the cartridge. For example, a gear system with gear 104 in contact with an external surface of the cartridge shutter mechanism 106 that has linear track 55 of grooves can be actuated by the motion of the cartridge in the z direction produced by the cartridge loader. The mechanical work done by the cartridge loader in the z direction can be stored in a spring that is wound driven by such gear. Once the cartridge is fully loaded, the energy stored by wound spring can be discharged into a separate gear motor to gear 104 that opens the shutter mechanism.
In
The HDSS require dynamic control and is connected via cables 110 (e.g., electrical or optical) to one or more controllers 106c. The controllers within the HDSS can perform a multitude of tasks including, but not limited to, the control and timing of the data displayed by the SLM, the modulation and power levels of the optical source, the decoding of data received from the detector, the servo controls for tracking the holographic media, and the control and timing of the reference beam wavefront and or angle required for the specific multiplexing configuration of the HDSS. The controller can also supply any electrical power needed by these various opto-mechanical systems via the connections illustrated by 110. The HDSS internal controller(s) are connected to an external controller 112 via a connection 111. This external controller could be a variety of controllers that include, but are not limited to, a personal computer, an enterprise library data storage system, or a computer server. The controller 106c may represent electronic, such as a programmed microprocessor based (or computer) system within housing 1. Signal may be sent or received by controller 106c from the components in housing shown for example by cables 110. For example, such signals send or received: signals to the motor for rotating gear 104; signals received from contact switch 104a; data signals representing data from detector 103 (or signals to detector 103 to control detector 103 operation); signals to beam steering system 17 to control angle of the reference beam; signals to the SLM 19 in accordance with data to be written; signals to source 15 to control operation of the source; signals to the positioning mechanism of stage 10 (in one or more orthogonal axes x,y,z) and via motor 5 (position along rotational axis 9 of the spindle). Thus, the holographic media is positioned by rotation about axis 9 and linear motion along axis z to write data or read data from media 4.
Other optical systems for read and/or write operations may also be used, such as described in U.S. Pat. No. 5,621,549, which is herein incorporated by reference. Although the holographic optics are preferably stationary, all or part of the optics may also be movable over the media. In addition to read or write operations, the holographic optical system may also provide searching operations to locate holographic recorded data on the media.
Referring to
An optional hub 8 of media 4 is shown in
Referring to
The cartridge in
The shutter mechanism 106 in the cartridge 3 is provided by a shutter member 106a and a hub cover or shutter 106b. Shutter member 106a has a vertical wall 48 of a length along at least half of the circumference of the circular chamber 42, a bottom wall 50, and a slot 52 opposite vertical wall 48. The vertical wall 48 and bottom wall 50 of shutter member 106a meet to form a surface 54, which may be angled, such as 45 degrees. Angled surface 54 extends from one end 54a along the circumference of the shutter member 106a to another end 54b. A circular row of teeth provides a gear track 55 on angled surface 54 along the outer circumference of shutter member 106a. The chamber bottom wall 46 may be slightly concave and shutter bottom wall 50 is also slightly concave such that it is slidable along bottom wall 46 when rotated in chamber 42. Friction can be reduced by having concave walls, but one may also use other specific wear zones (e.g., raised dots, ribs, etc.) that may incorporate low-friction materials that are different from the materials of walls 50 and 46. The vertical wall 48 of shutter member 106a rides in a vertical slot or track 49 in the upper housing member 40a along a downwardly curved edge 40c of top wall 44 which provides a lip above window 105, and such track 49 extends through steps 41b adjacent ledges 41a. An upwardly curved edge 46f of bottom wall 46 provides a lip below window 105 on either side of slot 45. A stop 47 abuts end 48a of the vertical wall 48 of the shutter member 106a when the shutter member is fully rotated to close window 105, or end 48b when the shutter member is fully rotated to open window 105. The top edge 40c is thus mated with a circular slot 49 in the top wall 44, creating an overlap between shutter member 106a and top wall.
The hub cover 106b is disposed in a recessed region 46a along the interior of bottom wall 46 between bottom wall 46 and shutter member 106a. The hub cover 106b is rotatably mounted in chamber 42 via a hole 58 of hub cover 106b upon a pivot post 56 extending from bottom wall 46. The hub cover 106b may be coupled for rotation upon post 56 with either a mechanical fastener (such as an E-ring on the post 56), or a washer and heat stake. A heat stake is the formation of a rivet head on the top of a post usually by means of heat or physical deformation. Hub cover 106b has at one end a lobe 60 and at the other end a drive pin 61. The drive pin 61 may be a cylindrical member protruding from the surface of the hub cover 106b. When shutter member 106a is fully rotated to close window 105, the drive pin 61 is received in a notch 62 of the shutter member 106a. A torsion spring (or a linear extension spring) 56a is provided about post 56 having ends that abut the hub cover 106b and the chamber bottom wall 46. The torsion spring biases the hub cover 106b in its closed position (in a clock-wise direction from top view). The pocket shape of region 46a cut into the interior surface of the cartridge bottom wall 46 forms an optional stop wall 46c which may be provided for the hub cover 106b when rotated to its closed position. Optionally, wall 46d for the hub cover 106b may provide a stop when the hub cover is rotated to its open position. Preferably, hub cover 106b does not require a stop as the open and close stop positions of hub cover rotation is determined by the open and close positions, respectively, of the shutter mechanism 106a. The hub cover and shutter member may be fabricated from the same material providing housing 40.
The assembled cartridge with the shutter member 106a and hub cover 106b in a closed position over window 105 is shown in
To open window 105, the gear 104 is driven by motor 53b to rotate shutter member 106a clockwise (from a top view) sliding vertical wall 48 of the shutter member 106a in track 49 and then along vertical walls 43, until end 48b of vertical wall 48 of the shutter member 106a abuts stop 47, thereby fully containing shutter member 106a in chamber 42 and aligning slot 52 of shutter member 106a to coincide with slot 45 in chamber bottom wall 46. Hub cover 106b rotates in response to rotation of shutter member 106a when drive pin 61 rides along a cam surface 51 of the shutter member 106a rotating the hub cover 106b in a clockwise direction against the bias of spring 56a to pivot lobe 60 away from slot 45, and enable access to the hub 8 of media 4. When shutter member 106a drives against stop 47 to limit its travel in either its open or close positions, this in turn also limits the hub cover 106b travel. Other means may also be provided to determine when shutter member 106a is fully open or closed. For example, in addition to the mechanical stop 47, optical or mechanical sensor(s) may be provided in housing 1 to detect (via signals to controller 106c) the shutter member 106a position to control the on/off function of the driving gear motor 53b that moves the shutter member 106a. In a further example, mechanical stop 47 is used and the current of external motor 53b is monitored (via signals to controller 106c) to determine which mechanical stop 47 has reached shutter member 106a.
The cartridge upper and lower housing members 40a and 40b have walls 63a and 63b, respectively, continuous with the top wall 44 and bottom wall 46, respectively, which mate with each other to define a rectangular end of the cartridge opposite window 105. Notches 40e may be provided for optional use by the other loaders external of housing 1 of the system to grab the cartridge, such as in a library system. For example, the cartridge may have notches 40e, as well as the holes 64, 66, and 68, such as described in an international standards document ISO/IEC 10089 title “Information technology—130 mm rewriteable optical disk cartridge for information interchange”. For the case of notches 40e, these are similar to notches for 5¼ inch MO (Magnetic-Optical) cartridges such that the MO cartridges can be grabbed by the robotic cartridge handling system within an automated MO library. This can allow for the efficient containment of a 130 mm data storage media while conforming to many of the specifications described in ISO/IEC 10089 and allowing for the complete front of the cartridge to open up thereby allowing for the actuation of the storage media outside of the cartridge.
Screws may couple the upper and lower housing member 40a and 40b together which are received through holes 64 (
The cartridge shutter member 106a and hub cover 106b may be locked so that they cannot be opened without the appropriate unlocking mechanism as would be contained within the inside of the mating HDSS. One example of the interlock mechanism is to employ a simple spring and lever arrangement that engages a detent in the shutter. An access hole in the cartridge walls 63b and 43 (or in wall 44 or wall 46) will allow a plunger from the disk drive to push the lever out of the detent, freeing the shutter member 106a to rotate. A light-tight lever is provided so that the access hole in the cartridge need not create a light leak. Another example of a locking means is a magnetic latch and spring. In this example, a spring holds the locking lever into the shutter detent. A magnet (or magnetizable keeper) is located in a position so that a magnet in disk drive will pull the detent lever out of the locked position. The advantage of the magnetic latch is twofold: no chance for light to leak; and no access hole for curious users to poke at and accidentally unlock the shutter member and ruin their data. A redundant magnetic latch on either side of the cartridge may be provided for additional protection.
The cartridge 3 of
There are several features of the compact removable-disk cartridge 3: (1) The shutter rotates about the disk center, so clearance between the shutter and disk OD is preserved in all positions (open, closed, and during motion); (2) the curved “wraparound” flanges (or tabs) 43a in
Although the positioning mechanism for the media to a position fully or partially from the cartridge is coupled to the media through a bottom wall of the cartridge, instead such coupling of the positioning mechanism to the media (e.g., via spindle) may be through an opening similar to slot 45 through the top wall of the cartridge with the hub covering means of
In the cartridge, the media disk 4 may sit on three or more support tabs 70 mounted in a spaced relation along the interior of the shutter vertical wall 48 (
The shutter member 106a thus combines several functions in one part. It acts as a door for blocking the window 105 through which the disk exits and enters the cartridge housing. The shutter member 106a acts as a light seal to prevent exposure of the photo-sensitive disk. Third, the shutter member 106a acts as an actuator for the hub cover 106b. Fourth, it provides a gear rack 55 upon which motor 53b with a complementary gear 104 (or friction drive, or spoke drive) engages the shutter gear rack 55 to actuate opening or closure of window 105. The light seal of the shutter member 106a is accomplished on the bottom by molding or forming the shutter member from one piece of material without holes. All the interior surfaces of chamber 42 in the cartridge are appropriately textured and painted (or molded) material with excellent optical absorption to minimize light scatter off surfaces that may provide a path into the disk 4.
As described earlier, if the HDSS operates only upon a read-only HDSS and a read-only holographic media, the HDSS and the cartridge 3 for the read-only holographic media need not be light-tight. For the read-only HDSS, for example, one does not require the aperture 2 through which the cartridge is inserted to be light-tight. The cartridge 3 for the read-only holographic media, for example, could be fabricated from a transparent or translucent material such as certain grades or compositions of acrylics and polycarbonates. In the read-only media case, optionally no cartridge is required to house the holographic media and instead the bare media may be handled and insert it into the HDSS. This invention would still apply in that the HDSS could be actuating the media linearly or in more than one direction across the optical pickup of the HDSS.
The system for enabling a data storage media to be actuated to positions partially or completely outside of the cartridge that originally housed said media is not limited to holographic data storage applications, but for all data storage applications including, but not limited to other forms of optical data storage as well as magnetic data storage.
Although the cartridge has been shown to having a window, alternatively, the cartridge may be of a clamshell housing such that when the cartridge is loaded into the drive, the top half and the bottom half of the cartridge housing opens up, via a spring on the back of the cartridge, thereby allowing the data storage media to be actuated outside of the cartridge that originally housed said media. In another example, the shutter member 106a need not be a rotary one that slides open and closed, but could be a shutter (or door) that flips open or closed.
Thus, the present invention provides placement of a holographic media within a package, referred to herein as cartridge 3. The cartridge is capable of being loaded into a HDSS via an external aperture 2 of the HDSS. Once the cartridge 3 is inside of the HDSS, a portion of the cartridge opens to allow the positioning mechanism of the HDSS to partially or completely remove the holographic media 4 from the cartridge 3 and to position or move it over the write and/or read optical system of the HDSS. Once the writing and/or reading process is completed, the HDSS positioning mechanism reinserts the holographic media within the cartridge and the cartridge is ejected from the HDSS.
As stated earlier, for a HDSS that is capable of recording data to writeable holographic media, the preferred embodiment has light-tight requirements on both the HDSS and the cartridge of the writeable holographic media. The term “light-tight” is defined herein as the property of a physical barrier wherein, if the barrier does transmit electro-magnetic radiation, the barrier only transmits electro-magnetic radiation that the holographic media for a specific application is not sufficiently sensitive to so as to cause an undesired change in the holographic media that in some manner compromises the performance that the holographic media was designed for. Such transmitted electro-magnetic radiation means radiation the cartridge would be expected to encounter during normal use and operation. In this embodiment, the cartridge is preferably made from materials, coated material, or composites of materials that achieve a light-tight cartridge at the wavelengths that the holographic media is sensitive to, as well as a cartridge wherein all seams of the cartridge are made light-tight through the use of light baffling geometries or other means. Any doors, apertures, or windows allowing access to the holographic media are made light-tight through a locking mechanism or other light baffling or absorption geometries. In a preferred embodiment, a lock-mechanism is integrated into the cartridge such that the door, aperture, or window that allows access to the holographic media cannot be opened without a suitable unlocking mechanism.
For the HDSS capable of writing to holographic media, the external aperture 2 of the HDSS through which the cartridge 3 is inserted is preferably light-tight. Although the external aperture need not to be light-tight during the loading or unloading of a cartridge, in the preferred embodiment, when the cartridge 3 is either fully inserted into the HDSS or when the cartridge is fully ejected from the HDSS, the external aperture maintains a light-tight seal.
Within the HDSS, a cartridge loader may be provided which engages the cartridge and can be used to pull said cartridge into the HDSS. The cartridge loader is such that the cartridge aperture allows access to the media and the aperture does not open until the cartridge is fully within the HDSS and the external aperture of the HDSS is light-tight. Optionally, the cartridge may be partially loaded sufficient to access the media in which the light cannot pass through the gap between the cartridge and the aperture. When the HDSS is light-tight again after insertion of the cartridge, a motor driven mechanism opens the cartridge such that the holographic media within said cartridge can be removed. The positioning mechanism of the HDSS then remove the holographic media from the cartridge and scan the holographic media over the optical pickup of the HDSS. In one embodiment, the scanning of the holographic media can be accomplished via a rotation and a radial translation in the case of holographic media that is in the format of a disk. In another embodiment, the scanning of the holographic media is accomplished in an x-y format or another motion format that is capable of accessing the full 3-D profile of the holographic media. As an example, holographic media in the form of a planar card can be removed from the cartridge and the holographic media can be scanned in x and y (two non-parallel axes of motion that lie in the plane of the surface of the holographic media) or the holographic media can be scanned in only x or y and the write optical head of the HDSS can be scanned in another non-parallel axis of motion such that the entire surface of the holographic media can be accessed.
As stated earlier, if the HDSS operates only as a read-only HDSS and hence uses only read-only holographic media 4, the HDSS and the cartridge 3 for the read-only holographic media need not be light-tight. For the read-only HDSS, for example, one does not require the aperture 2 through which the cartridge 3 is inserted to be light-tight. The cartridge for the read-only holographic media, for example, could be fabricated from a transparent or translucent material such as certain grades or compositions of acrylics and polycarbonates. In this embodiment, the aperture of the cartridge through which the holographic media is accessed need not be light-tight. In another embodiment of the read-only media case, one can forego the use of a cartridge to house the holographic media and instead handle the bare media and insert it into the HDSS. This invention would still apply in that the HDSS could be actuating the media linearly or in more than one direction across the optical pickup of the HDSS.
Another example of a HDSS system that may not require the condition of a light-tight housing and/or a light-tight cartridge, is one that is bit-based, see for example, S. Orlic et al., “3D bit-oriented optical storage in photopolymers”, J. of Optical A: Pure Appl. Opt., Vol. 3, pp. 72-81 (2001). In bit-based HDSS, the holographic data is recorded one bit at a time, instead of an array of bits, either 1-D or 2-D, as the recording is in page-based systems. In bit-based recording, the bits are recorded in the volume of the HDSS media, but within said volume of the media, the desired recording spot size may be on the order of a few cubic microns, as opposed to tens of thousands of cubic microns for some page-based holographic systems. As a consequence, holographic media for bit-based systems may have a thresholding requirement such that recording within the holographic media can only take place if the media is exposed to a very high optical power density. The power density threshold may be higher than that received through exposure to normal room lights of an office or home environment, and may also be envisioned to be a higher power density than would be received by the non-focused rays of the sun if the media is carried outdoors. The bit-based HDSS and associated media may therefore not require a light-tight specification, even though the HDSS and media for recording (writing) of data and therefore not restricted to only reading data.
From the foregoing description it will be apparent that there has been provided improved system, apparatus, and method for accessing holographic media in a holographic drive of a holographic data storage system, and media containing cartridges for use therewith. The illustrated description as a whole is to be taken as illustrative and not as limiting of the scope of the invention. Such variations, modifications and extensions, which are within the scope of the invention, will undoubtedly become apparent to those skilled in the art.
This application claims the benefit of priority to U.S. Provisional Application No. 60/510,914, filed Oct. 14, 2003, which is herein incorporated by reference.
Number | Date | Country | |
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60510914 | Oct 2003 | US |