Classifications

• • G—PHYSICS
  • G11—INFORMATION STORAGE
  • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
  • G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
  • G11B7/004—Recording, reproducing or erasing methods; Read, write or erase circuits therefor
  • G11B7/0065—Recording, reproducing or erasing by using optical interference patterns, e.g. holograms
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
  • G03H1/00—Holographic processes or apparatus using light, infrared or ultraviolet waves for obtaining holograms or for obtaining an image from them; Details peculiar thereto
  • G03H1/02—Details of features involved during the holographic process; Replication of holograms without interference recording
  • G03H1/0252—Laminate comprising a hologram layer
• • G—PHYSICS
  • G11—INFORMATION STORAGE
  • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
  • G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
  • G11B7/08—Disposition or mounting of heads or light sources relatively to record carriers
  • G11B7/09—Disposition or mounting of heads or light sources relatively to record carriers with provision for moving the light beam or focus plane for the purpose of maintaining alignment of the light beam relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following
  • G11B7/0938—Disposition or mounting of heads or light sources relatively to record carriers with provision for moving the light beam or focus plane for the purpose of maintaining alignment of the light beam relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following servo format, e.g. guide tracks, pilot signals
• • G—PHYSICS
  • G11—INFORMATION STORAGE
  • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
  • G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
  • G11B7/24—Record carriers characterised by shape, structure or physical properties, or by the selection of the material
  • G11B7/2403—Layers; Shape, structure or physical properties thereof
  • G11B7/24035—Recording layers
  • G11B7/24044—Recording layers for storing optical interference patterns, e.g. holograms; for storing data in three dimensions, e.g. volume storage
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
  • G03H2250/00—Laminate comprising a hologram layer
  • G03H2250/37—Enclosing the photosensitive material

Definitions

• the present invention relates to a holographic recording medium and a method for recording and reproducing the same.
• a holographic recording medium has attracted attention as a large-capacity and high-speed accessible recording medium.
• the recording medium itself has an address signal and a servo signal.
• Japanese Patent Application Laid-Open No. 2002-63733 discloses a holographic recording medium. A technique for forming a concavo-convex pattern on a substrate of a graphic recording medium has been proposed.
• the present invention has been made to solve the above problems, and has excellent moisture resistance, heat resistance, rigidity, and can reliably detect position information. It is an object of the present invention to provide a holographic recording medium capable of advanced recording / reproducing control, and a recording / reproducing method thereof.
• holographs that are excellent in moisture resistance, heat resistance, and rigidity, can reliably detect position information, and can perform advanced recording and reproduction control.
• a recording medium and a method for recording and reproducing the same have been found.
• the hologram recording layer has a structure sandwiched between two substrates made of a glass material, and the marker is provided on at least one of the two substrates.
• the holographic recording medium according to any one of the above (1) to (3).
• An anti-reflection layer for preventing surface reflection of the recording light or reproduction light is formed on at least one of the surface on which the recording light or reproduction light is incident and the opposite side.
• It has a substrate made of a glass material and a hologram recording layer provided on the substrate, and a marker is provided on the surface of the substrate as position information in the hologram recording layer.
• a holographic recording / reproducing method characterized by detecting with light having a wavelength different from light.
• FIG. 1 is a schematic side sectional view of a holographic recording medium according to the present embodiment.
• FIG. 2 is a schematic cross-sectional side view of the vicinity of a marker in the holographic recording medium.
• FIG. 4 is a schematic side view showing the signal light and the reference light viewed from the arrow IV in FIG.
• FIG. 5 is a schematic side view showing marker detection light as viewed from an arrow IV in FIG. 3
• FIG. 7 is a schematic side view showing the signal light, the reference light, and the marker detection light viewed from the arrow VII in FIG.
• FIG. 8 is a schematic side view showing another example of the holographic recording / reproducing method according to the present embodiment.
• a holographic recording medium includes a substrate made of a glass material, and a hologram recording layer provided on the substrate. The above problem has been solved by providing markers as position information.
• a holographic recording medium 10 includes a substrate 12 made of a glass material and a hologram recording layer 14 provided on the substrate 12.
• a substrate 12 made of a glass material
• two substrates 12 are provided so as to sandwich the hologram recording layer 14.
• the refractive index of the substrate 12 and the refractive index of the hologram recording layer 14 are preferably substantially equal, and specifically, the difference in the refractive index is preferably less than 0.05.
• a marker 16 is provided on the lower surface (the surface of the substrate 12) 10A of the holographic recording medium 10 as positional information on the hologram recording layer 14, and in this example, the marker 16 has a resolution of 2400 dpi. It is formed by inkjet printing.
• the lower surface 10A of the recording medium 10 is the surface of the substrate 12 opposite to the side on which the hologram recording layer 14 is provided, and the surface opposite to the side on which recording light or reproduction light is incident.
• the resolution of the marker 16 by printing is at most a few xz m. In recording and reproducing a force hologram, a resolution of about several xm is sufficient. That is, even when the shift multiplexing method capable of high-density recording is applied, the moving pitch of the light spot of the recording light or the reproduction light is about several tens of ⁇ m, and the marker 16 can be used at the same pitch.
• the marker 16 includes a pigment layer 18 having a high reflectance and a protective layer 20 made of a transparent pigment.
• the marker 16 includes a print pattern PP1 in which a plurality of substantially circular dots are arranged in a straight line at a predetermined interval, and a substantially bar-shaped line at a predetermined interval.
• a print pattern PP1 in which a plurality of substantially circular dots are arranged in a straight line at a predetermined interval, and a substantially bar-shaped line at a predetermined interval.
• These printing patterns PP1 and PP2 are in the traveling direction X of the recording light or the reproduction light (the holographic recording medium 10 is In the case of the disk type, the printing is performed substantially in parallel at a predetermined interval L along the circumferential direction).
• the interval L between the print patterns PP1 and PP2 is set to a width that does not allow the signal light LB1 and the reference light LB2, which are recording light or reproduction light, to pass through the marker 16.
• the interval L between the print patterns PP1 and PP2 is about 500 ⁇ .
• the total surface area of all the printed patterns is preferably 1/5 or less with respect to the surface area of the substrate 12, more preferably 1/20 or less.
• the hologram recording layer 14 has a thickness of about 0.1 mm to several mm.
• a material containing a monomer material capable of performing a photopolymerization reaction can be used.
• a photopolymer-based recording material composed of the monomer material and the matrix material can be used. Films and the like are preferred.
• the hologram recording layer 14 is sealed by two substrates 12 and a sealing layer 22 disposed between the two substrates 12.
• the sealing layer 22 is composed of a metal foil 24 made of a metal material and a glass block 26 made of a glass material.
• the sealing layer 22 has a role of preventing moisture permeation to the hologram recording layer 14. It also serves as a spacer to keep the distance between them almost constant.
• an anti-reflection layer (not shown) for preventing surface reflection of recording light or reproduction light is formed. Note that the antireflection layer of the lower surface 1OA may be formed on the substrate before the marker 16 is provided, or may be formed after the marker 16 is provided.
• the holographic recording medium 14 includes the substrate 12 made of a glass material, and the hologram recording layer 14 provided on the substrate 12. Since the marker 16 is provided as position information, the marker 16 is excellent in moisture resistance, heat resistance, and rigidity, and can also reliably detect position information and perform advanced recording and reproduction control.
• the glass material has excellent moisture resistance, it is possible to prevent the hologram recording layer 14 from undergoing a dimensional change or a refractive index change due to moisture absorption. Further, since the glass material has a smaller thermal expansion than the resin material, a dimensional change hardly occurs with a temperature change. Further, since the glass material has excellent rigidity, it is possible to prevent a change in shape such as warpage of the holographic recording medium 10.
• the hologram recording layer 14 has a structure sandwiched between two substrates 12 and is sealed by a sealing layer 22 disposed between the two substrates 12. Thus, the hologram recording layer 14 can be protected more reliably.
• sealing layer 22 can also function as a spacer for keeping the distance between the two substrates 12 substantially constant, and there is no need to separately provide a spacer.
• the marker 16 is provided on the surface 10 A opposite to the side on which the recording light or the reproduction light is incident, the marker 16 is provided before the recording light or the reproduction light enters the hologram recording layer 14. Therefore, the light is reduced or noise is generated during recording / reproducing. Can prevent the force S.
• the marker 16 is provided on the surface 10 A of the substrate 12 opposite to the side on which the hologram recording layer 14 is provided, the marker 16 can be easily formed.
• an antireflection layer for preventing surface reflection of recording light or reproduction light is formed on the upper surface 10B and the lower surface 10A of the hologram recording medium 10, so that generation of noise due to surface reflection is prevented. be able to.
• the holographic medium according to the present invention is not limited to the shape, the structure, and the like of the holographic medium 10 according to the embodiment.
• the print pattern of the marker 16 is changed to PP1 and
• the print pattern of the marker 16 may be one type or three or more types. Further, the shape of the print pattern may be another shape such as a square shape.
• the printing method of the force marker 16 in which the marker 16 is printed by the ink jet method is not limited to this, and the marker 16 may be printed by screen printing or the like.
• the marker 16 is printed on the surface 10A opposite to the side where the recording light or the reproduction light is incident.
• printing may be performed on the surface 10B on the side where recording light or reproduction light is incident.
• the marker 16 is composed of the pigment layer 18 and the protective layer 20, but the pigment layer 18 alone may be used.
• the protective layer 20 may be formed by a method other than printing (for example, spin coating) separately from the pigment layer 18.
• a holographic recording medium includes a substrate made of a glass material, and a hologram recording layer provided on the substrate, and a marker is used as position information in the hologram recording layer. Is provided, and if you do,
• marker light LB3 having a wavelength different from the signal light LB1 and the reference light LB2, which are hologram recording light (or reproduction light), is used.
• the marker detection light LB3 for example, when the signal light LB1 and the reference light LB2 are blue laser light having a wavelength of 405 nm, red laser light having a wavelength of 650 nm can be used.
• FIGS. 5 and 7 by irradiating the marker 16 with the marker detection light LB3 and detecting the reflected light, position information on the hologram recording layer 14 can be obtained.
• the marker 16 is an edge detection which is not a level detection. Recording (reproduction) of the hologram is performed based on the position information detected in this manner.
• the marker 16 can be positioned in the direction Y perpendicular to the traveling direction X (d, so-called tracking servo), or can be used as a holograph. It is also used for positioning in the thickness direction Z of the recording medium 10 (d, so-called focus servo).
• the marker 16 is detected by light having a wavelength different from the recording light (reproducing light) for recording (reproducing) the hologram.
• the hologram recording layer 14 can be suppressed from being exposed to light, and the mark detection light LB3 is used as a separate light source from the signal light LB1 and the reference light LB2. Can be performed in parallel.
• the marker 16 can be used not only as an address signal but also as a servo signal. Control is possible.
• the holographic recording (reproducing) method according to the present invention is not limited to the holographic recording (reproducing) method according to the above embodiment.
• the force for detecting the marker 16 by reflecting light is not limited to this.
• the present invention is not limited to this, and the marker 16 may be detected by transmitting light. Therefore, for example, as shown in FIG. 8, the marker 16 is detected by irradiating the marker 16 with reference light LB2, which is recording light (or reproduction light), and detecting the marker 16 by the transmitted light. Therefore, the size and cost of the recording / reproducing apparatus for the holographic recording medium 10 which does not require a separate light source can be realized.
• the position of the holographic recording medium 10 in the thickness direction Z can be detected when the focus of the reference light LB2 is adjusted.
• the light spot diameter is narrowed, so the detection sensitivity of marker 16 is further improved The ability to make S.
• the pigment used for the marker 16 has a low reflection of the reference light LB2 and is sufficiently absorbed.
• a method of detecting the focus for example, a method of finding a point at which the On / Off differential signal of the marker 16 becomes maximum can be adopted.
• the holographic recording medium and its recording / reproducing method of the present invention in addition to being excellent in moisture resistance, heat resistance and rigidity, position information can be reliably detected and advanced recording / reproducing control can be performed. Can be.

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• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Optical Recording Or Reproduction (AREA)
• Optical Record Carriers And Manufacture Thereof (AREA)
• Optical Head (AREA)
• Holo Graphy (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (1)

Family

ID=35150221

Family Applications (1)

Country Status (2)

Families Citing this family (3)

Citations (4)

• 2004
  • 2004-04-12 JP JP2004117006A patent/JP2005302149A/ja active Pending
• 2005
  • 2005-03-22 WO PCT/JP2005/005115 patent/WO2005101385A1/ja active Application Filing

Patent Citations (4)

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