WO2011027472A1 - Optical information recording medium - Google Patents

Optical information recording medium Download PDF

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Publication number
WO2011027472A1
WO2011027472A1 PCT/JP2009/065594 JP2009065594W WO2011027472A1 WO 2011027472 A1 WO2011027472 A1 WO 2011027472A1 JP 2009065594 W JP2009065594 W JP 2009065594W WO 2011027472 A1 WO2011027472 A1 WO 2011027472A1
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WO
WIPO (PCT)
Prior art keywords
information recording
layer
recording medium
optical information
recording layer
Prior art date
Application number
PCT/JP2009/065594
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French (fr)
Japanese (ja)
Inventor
真一 立田
留美子 早瀬
勝哉 寺井
主税 谷岡
Original Assignee
株式会社 東芝
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Application filed by 株式会社 東芝 filed Critical 株式会社 東芝
Priority to PCT/JP2009/065594 priority Critical patent/WO2011027472A1/en
Publication of WO2011027472A1 publication Critical patent/WO2011027472A1/en

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    • 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
    • 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
    • G11B7/004—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
    • G03H2250/00—Laminate comprising a hologram layer
    • G03H2250/37—Enclosing the photosensitive material

Definitions

  • the present invention relates to an optical information recording medium, and more particularly to an optical information recording medium for recording and reproducing information as a hologram.
  • optical information recording media that record and reproduce information as holograms have attracted attention as high-density recording media. Since this optical information recording medium is a volume recording medium, it has a higher recording density than a surface recording DVD (Digital Versatile Disk) or the like. In the case of a DVD or the like, the recording mark is generally represented by ON / OFF bit data. On the other hand, in a holographic memory, a large amount of information is modulated at once and recorded as interference fringes. This information is called page data in units of two-dimensional barcode-like recording / playback data composed of black and white dots.
  • One method for increasing the recording density of a holographic memory is a multiple recording method.
  • This multiple recording method is a method of recording a plurality of page data in the same location of the holographic memory. For example, angle multiplex recording in which the laser beam irradiation angle is shifted, shift multiplex recording in which the laser beam irradiation position is slightly shifted, and the like.
  • the interference method between the information beam and the reference beam the information beam and the reference beam are incident on the medium as separate beams and interfere with each other. The information beam and the reference beam are interfered by passing through the same objective lens. There is a coaxial method to let you. Regardless of the multiplexing method or interference method, interference fringes are recorded on the information recording layer of the holographic memory. The information recording layer is sandwiched between a pair of substrates.
  • the thickness of the information recording layer is 10 to 11 microns, and the absolute value of the product of the difference between the linear expansion coefficients of the substrate and the information recording layer and the temperature difference between recording and reproduction is 1/100 or less.
  • the disturbance of interference fringes is unlikely to occur.
  • the degree of freedom in selecting the material of the optical information recording medium is impaired.
  • An object of the present invention is to provide a more reliable optical information recording medium without impairing the freedom of material selection.
  • an optical information recording medium that records and reproduces information as a hologram, and includes a first substrate, a second substrate facing the first substrate, and the first substrate. An information recording layer sandwiched between the second substrate, a first deformation layer provided between the first substrate and the information recording layer, the second substrate and the information recording There is provided an optical information recording medium comprising: a second deformation layer provided between the layers.
  • a more reliable optical information recording medium is realized without impairing the freedom of material selection.
  • FIG. 1 is a schematic diagram of a main part of an optical information recording medium.
  • FIG. 1 (a) shows the top surface of the main part of the optical information recording medium 1
  • FIG. 1 (b) shows the XY cross section of FIG. 1 (a).
  • the optical information recording medium 1 is an optical information recording medium (holographic memory, hologram recording medium) that records and reproduces information as a hologram.
  • the optical information recording medium 1 includes an opposing substrate 10 and substrate 11, an information recording layer 30 sandwiched between the substrate 10 and the substrate 11, and a deformation layer provided between the substrate 10 and the information recording layer 30. 20 and a deformation layer 21 provided between the substrate 11 and the information recording layer 30.
  • the opposing substrates 10 and 11 are flat, and flat deformation layers 20 and 21 are provided inside thereof.
  • the deformation layer 20 and the deformation layer 21 face each other.
  • An information recording layer 30 is sandwiched between the deformation layer 20 and the deformation layer 21.
  • Ring-shaped spacers 40 are provided between both end portions 10 t of the substrate 10 and both end portions 11 t of the substrate 11. Since the spacer 40 is provided between the opposing substrates 10 and 11, the thickness of the optical information recording medium 1 can be defined.
  • a space 50 is provided between the deformation layers 20 and 21 and the information recording layer 30 and the spacer 40. As a result, a free space is formed between the substrate 10 and the substrate 11 around the information recording layer 30.
  • the information recording layer 30 and the deformation layers 20 and 21 are sealed by the substrates 10 and 11 and the spacer 40. Even if the spacer 40 is not provided, the thickness of the optical information recording medium 1, the parallelism between the substrates 10 and 11, the strength of the substrates 10 and 11, and the sealing performance of the information recording layer 30 and the deformation layers 20 and 21 are maintained. If necessary, the spacer 40 may be removed as appropriate. Instead of the spacer 40, an opaque adhesive member or filling member may be used. An uneven shape (track), a dichroic mirror, a reflective layer, and the like may be provided inside the substrates 10 and 11.
  • the material of the substrates 10 and 11 include resins such as inorganic glass, polycarbonate, and polymethyl methacrylate resin.
  • the materials of the substrates 10 and 11 are not limited to these.
  • the materials of the substrates 10 and 11 have sufficient optical conditions such as a sufficient transmittance for light used for recording and reproduction, a low birefringence, and the like as an optical recording medium. What is necessary is just to be able to maintain a sufficient strength.
  • an antireflection film may be applied to the main surfaces of the substrates 10 and 11 on which light enters and exits.
  • the material of the information recording layer 30 corresponds to, for example, a photopolymer.
  • the photopolymer is a photosensitive material using photopolymerization of a polymerizable compound (monomer).
  • the main component of the photopolymer contains a polymerizable compound, a photopolymerization initiator, and a porous matrix that plays a role of volume retention before and after recording.
  • the information recording layer 30 contains a three-dimensional cross-linked polymer matrix, a photo radical polymerization initiator, and a ring-opening polymerizable compound having an aliphatic cyclic structure that undergoes ring-opening polymerization by radicals.
  • Ring-opening polymerizable compounds include, for example, vinylcyclopropane compounds, cyclic sulfide compounds, bicyclobutane compounds, vinyl cyclic butane compounds, vinyl cyclic sulfone compounds, cyclic ketene acetal compounds, methylene dioxolane compounds, cyclic allyl sulfide compounds, benzocyclobutene compounds. , Xylylene dimer compounds, and cyclic disulfide compounds.
  • the aliphatic ring structure of the ring-opening polymerizable compound includes cyclic sulfide structure, bicyclobutane structure, vinylcyclopropane structure, vinyl cyclic sulfone structure, 4-methylene-1,3-dioxolane structure, cyclic ketene acetal structure, 8-methylene- 1,4-dioxaspiro- [4.5] deca-6,9-diene structure, cyclic allyl sulfide structure, cyclic ⁇ -oxyacrylate structure, benzocyclobutene structure, o-xylylene dimer structure, exomethylene structure It is selected from the group consisting of a structure having a spiroorthocarbonate structure in the molecule and a structure having an exomethylene structure and a spiroorthoester structure in the molecule.
  • the aliphatic cyclic structure is selected from the group consisting of 1-cyclopropyl-1-phenylethene, 1-cyclopropyl-1-tribromophenylethene, and 1-cyclopropyl-1-naphthylethene.
  • a three-dimensional cross-linked polymer matrix is obtained by polymerizing an epoxy monomer by epoxy-amine polymerization, epoxy-acid anhydride polymerization, or epoxy homopolymerization.
  • the radical photopolymerization initiator is selected from the group consisting of imidazole derivatives, organic azide compounds, titanocenes, organic peroxides, and thioxanthone derivatives.
  • the material of the information recording layer 30 is not limited to these. For example, dichromated gelatin, photorefractive crystal, or the like may be used as the material of the information recording layer 30.
  • the thickness of the information recording layer 30 only needs to be sufficient to obtain a diffraction efficiency sufficient for signal reproduction and a sufficient angle resolution in angle multiplexing.
  • the thickness of the information recording layer 30 according to the present embodiment is preferably 100 ⁇ m or more, more preferably 1 mm or more, and preferably 100 ⁇ m or more and 2 mm or less. Note that the thickness of the information recording layer 30 may be appropriately changed according to the recording density of the information recording layer 30.
  • the material of the deformation layers 20 and 21 is a physically and chemically stable material. For example, a material that does not change physically and chemically even when irradiated with light used for recording and reproduction is used. Further, a material that does not easily cause a chemical reaction at the interface between the information recording layer 30 and the substrates 10 and 11 is used.
  • the material of the deformable layers 20 and 21 is any material (solid, gel) as long as it has a sufficient transmittance for light used for recording and reproduction and has optical conditions such as low birefringence. Etc.).
  • the deformation layer 20 and the deformation layer 21 have the same linear expansion coefficient and thickness. Thereby, regarding the deformation layer 20 and the deformation layer 21 which oppose, the asymmetric deformation
  • the deformable layer 20 and the deformable layer 21 may be made of different materials and thicknesses.
  • the thickness of the deformation layers 20 and 21 is preferably 10 ⁇ m to 500 ⁇ m. This is because if the thickness of the deformable layers 20 and 21 is smaller than 10 ⁇ m, the deformable layers 20 and 21 lose the function of expanding and contracting the information recording layer 30 isotropically. This is because if the thickness of the deformable layers 20 and 21 is larger than 500 ⁇ m, the deformable layers 20 and 21 themselves are easily bent and do not have the strength to hold the information recording layer 30.
  • the Young's modulus of the deformation layers 20 and 21 is preferably 1/10 or less of the Young's modulus of the information recording layer 30.
  • the linear expansion coefficient is one digit or more smaller than that of the information recording layer 30. Therefore, in order for the deformation layers 20 and 21 to alleviate the difference in linear expansion between the substrates 10 and 11 and the information recording layer 30 due to the temperature difference, the Young's modulus of the deformation layers 20 and 21 is the Young's modulus of the information recording layer 30. 1/10 or less is preferable.
  • the Young's modulus of the photopolymer is about 10 6 to 10 7 (Pa).
  • the hardness of the photopolymer is about 30 to 80 (JIS type A).
  • the Young's modulus of the deformation layers 20 and 21 is preferably 10 5 to 10 6 (Pa) or less.
  • the hardness of the deformable layers 20, 21 is replaced with hardness (JIS type A) or penetration (JIS K2220 1/4 cone), the hardness is 30 (JIS type A) or less, and the penetration is Is preferably 0 (JIS K2220 1/4 cone) or more.
  • the Young's modulus of polyimide resin which is a typical organic resin, is about 3.5 (GPa). Accordingly, the Young's modulus of the deformable layers 20 and 21 is 1/10000 to 1/1000 or less than the Young's modulus of the polyimide resin.
  • the Young's modulus of the information recording layer 30 is Er
  • the Young's modulus of the deformable layer 20 (or deformable layer 21) is Et
  • the thickness of the deformable layer 20 (or deformable layer 21) is Tt
  • (Er / Et) ⁇ Tt is more preferably 10 (mm) or more.
  • FIG. 2 shows the relationship between the thickness (Tt) of the deformed layer and Er / Et.
  • the horizontal axis of FIG. 2 indicates the thickness Tt (mm), and the vertical axis indicates (Er / Et).
  • the condition of (Er / Et) ⁇ Tt ⁇ 10 (mm) can be achieved in the region above the curve A in the figure.
  • the distortion of the information recording layer 30 is more sufficiently caused by the deformable layers 20 and 21. Alleviated.
  • the deformation layers 20 and 21 are softer than the information recording layer 30 and have strength to hold the information recording layer 30.
  • the Young's modulus and hardness (JIS type A) are converted according to the conversion table shown in FIG. 3 (see Toray Dow Corning Electronics Silicone Catalog). In this figure, the penetration (JIS K2220 1/4 cone), which is an index of hardness, is displayed.
  • the light transmittance of the deformation layer 20 or the deformation layer 21 is preferably 87% or more.
  • the light scattering after the light is incident on the optical information recording medium 1 is preferably as small as possible.
  • the birefringence of the deformation layers 20 and 21 is preferably lower. If the refractive index (Ne) of ordinary light passing through the deformation layers 20 and 21 and the refractive index (No) of extraordinary light are both between the refractive index of the substrates 10 and 11 and the refractive index of the information recording layer 30, the deformation will occur. Birefringence due to the layers 20 and 21 itself is not a problem.
  • the maximum value of the refractive index of the substrates 10 and 11 is N S1
  • the minimum value is N S2
  • the maximum value of the refractive index of the information recording layer 30 is N R1
  • the minimum value is N R2 .
  • a material that does not easily reflect light at the interface is selected.
  • the interface between the substrate 10 and the deformation layer 20 the interface between the substrate 11 and the deformation layer 21, the interface between the deformation layer 20 and the information recording layer 30, and the interface between the deformation layer 21 and the information recording layer 30. If the difference is close to zero, light reflection at these interfaces is unlikely. There is no practical problem even if the difference in refractive index at each interface is within 10%. Moreover, even if the difference in refractive index at each interface is 10% or more, the reflectance is several% or less, and there is no practical problem.
  • Specific materials for the deformable layers 20 and 21 include, for example, (1) silicone resins such as silicone gel and silicone rubber, (2) acrylic rubber, acrylonitrile butadiene rubber, isoprene rubber, urethane rubber, and ethylene propylene. Synthetic rubber selected from the group of rubber, chloroprene rubber, butadiene rubber, styrene butadiene rubber, (3) acrylonitrile / chlorinated polyethylene / styrene copolymer resin (Acrylonitrile Chlorinated polyethylene Styrene, ACS), etc.
  • thermotropic type thermo melting type
  • lyotropic type solution type liquid crystal polymer
  • Olefin type Olefin type
  • styrene type vinyl chloride type
  • polyester type polyamide Any thermoplastic elastomer selected from the group of systems M, (6) Epoxy resin, etc.
  • IVS5022, IVS5332, XE14-C2860, IVS4012, IVS4312, IVS4542, TSJ3150, XE14-C2042, XE14-B577814-B5778, XE13-C0810, manufactured by Momentive Performance Materials, Inc. IVSM4200, IVSM4500, etc. are mentioned.
  • the material of the spacer 40 corresponds to, for example, a fluorocarbon resin such as Teflon (registered trademark).
  • the substrates 10 and 11 are prepared (step S10).
  • An antireflection film may be provided on the main surface of these substrates 10 and 11.
  • the deformation layers 20 and 21 having good film thickness uniformity and surface flatness are formed on the main surfaces of the substrates 10 and 11 (step S20).
  • Such deformable layers 20 and 21 are previously formed on the main surfaces of the substrates 10 and 11 by a coating method, and then the coating layer is cured by, for example, natural curing, heat curing, UV irradiation curing, or the like.
  • the coating layer is cured by, for example, natural curing, heat curing, UV irradiation curing, or the like.
  • a coating device a spin coater, a bar coater, a film applicator etc. are used, for example.
  • Step S30 together with the spacer 40 for maintaining the distance between the substrates 10 and 11 and the chucking hub on the central axis of the optical information recording medium 1, the substrates 10 and 11 are bonded together with the information recording layer 30 interposed therebetween.
  • the optical information recording medium 1 is formed.
  • FIG. 1 does not show the chucking hub.
  • the periphery of the substrates 10 and 11 is sealed with a sealing material (step S40).
  • a defect inspection such as a bubble mixing inspection is performed (step S50).
  • the optical information recording medium 1 sealed with the sealing material is incorporated into the light shielding cartridge (step S60).
  • the processing method in each manufacturing process is not limited to the form mentioned above. The order of the manufacturing steps may be changed as appropriate.
  • the size of the substrates 10 and 11 may be the size of the optical information recording medium 1, or the substrates 10 and 11 larger than the optical information recording medium 1 may be prepared. Good. When the substrates 10 and 11 larger than the optical information recording medium 1 are prepared, the substrates 10 and 11 may be divided into appropriate sizes before being incorporated into the light shielding cartridge.
  • the substrate 10 provided with the deformable layer 20 and the substrate 11 provided with the deformable layer 21 face each other, and then the raw material of the information recording layer 30 is placed between the deformable layer 20 and the deformable layer 21. It may be injected. This raw material is cured by natural curing, heat curing, UV irradiation curing, or the like.
  • optical information recording medium 1 Next, the function and effect of the optical information recording medium 1 will be described while comparing the optical information recording medium 1 with a comparative example.
  • symbol is attached
  • FIG. 5 is a diagram for explaining the operating principle of the optical information recording medium.
  • an optical information recording medium 1 is shown as the recording medium.
  • the recording method a two-beam interference method is shown, and in addition to the optical information recording medium 1, information light 31 and reference light 32 are shown.
  • Information is recorded on the optical information recording medium 1 by, for example, irradiating the information recording layer 30 with the information light 31 and the reference light 32 having a wavelength of 405 nm. At this time, light interference fringes generated by the intersection of the information light 31 and the reference light 32 are recorded in the information recording layer 30.
  • the information light 31 has information (not shown) by spatially modulating the laser light with a spatial light modulator (SLM) such as a liquid crystal element or a digital micromirror device.
  • SLM spatial light modulator
  • the reference light 32 is generated from the same light source as the information light at the same wavelength as the information light.
  • FIG. 6 to 8 show schematic diagrams of the optical information recording medium and reproduced images of page data (for one page).
  • the page data is binary data arranged two-dimensionally. That is, the luminance of the information light is modulated corresponding to binary binary data and recorded on the information recording layer 30.
  • FIG. 6A shows the structure of an optical information recording medium according to Comparative Example 100
  • FIG. 6B shows a reproduction image of page data of Comparative Example 100.
  • the substrates 10 and 11 are in direct contact with the information recording layer 30, and the deformation layers 20 and 21 are not provided.
  • the thickness of the information recording layer 30 is 1 mm.
  • the temperature difference ( ⁇ T) of the optical information recording medium during recording and during reproduction is 25 ° C.
  • the linear expansion coefficient of the substrates 10 and 11 is one digit or more smaller than that of the information recording layer 30. Therefore, when a temperature difference ( ⁇ T) occurs in the optical information recording medium, the information recording layer 30 is more likely to expand and contract than the substrates 10 and 11.
  • the in-plane direction of the information recording layer 30 is constrained by the expansion rate and contraction rate of the substrates 10 and 11. For this reason, the expansion rate and contraction rate in the in-plane direction of the information recording layer 30 are approximately the same as those of the substrates 10 and 11.
  • the information recording layer 30 has a potential property of expanding and contracting more than the substrates 10 and 11 when a temperature difference occurs. For this reason, internal stress acts in the substrates 10 and 11, and the substrates 10 and 11 themselves are bent or bent. Along with this, the expansion rate and contraction rate in the thickness direction of the information recording layer 30 seem to be larger than in the in-plane direction. Therefore, the linear expansion coefficient of the information recording layer 30 has anisotropy, and the information recording layer 30 itself may be bent or wrinkled by the temperature difference of the optical information recording medium.
  • the interval of the recorded interference fringe changes in the page data (one page), and the interference fringe is inclined.
  • the incident angle of the reference light in the page data (for one page), the incident angle of the reference light, the interval between the wavelength and the interference fringe, the position where the angle can be reproduced, and the position cannot be reproduced without matching.
  • the entire surface of one page cannot be reproduced at a time, and the luminance signal of the reproduced information light has an annular shape (see FIG. 6B).
  • FIG. 7A shows the structure of an optical information recording medium according to Comparative Example 101
  • FIG. 7B shows a reproduced image of this page data.
  • Comparative Example 101 although the above-described deformation layers 20 and 21 are provided, part of both end portions of the substrates 10 and 11 are in contact with the information recording layer 30 (part indicated by an arrow B).
  • the thickness of the information recording layer 30 is 1 mm.
  • the temperature difference ( ⁇ T) of the optical information recording medium during recording and during reproduction is 25 ° C.
  • the thickness of the deformation layers 20 and 21 is 0.2 mm.
  • the material of the deformation layers 20 and 21 is CY52-276 manufactured by Toray Dow Corning.
  • the internal stress described above works in the substrates 10 and 11, and the substrates 10 and 11 themselves are It may be bent or crooked. Thereby, the linear expansion coefficient of the information recording layer 30 is apparently anisotropic. As a result, even in the comparative example 101, the reproduced luminance signal of the information light may have an annular shape (see FIG. 7B).
  • the deformable layers 20 and 21 are interposed between the substrates 10 and 11 and the information recording layer 30.
  • the deformation layers 20 and 21 are in contact with the entire main surface (upper surface and lower surface) of the information recording layer 30. That is, the information recording layer 30 is held by the deformation layers 20 and 21 from above and below.
  • the Young's modulus of the deformation layers 20 and 21 is 1/10 or less of the Young's modulus of the information recording layer 30, and the deformation layers 20 and 21 are softer than the information recording layer 30.
  • the optical information recording medium 1 even if the temperature rises and the information recording layer 30 expands, shear stress acts in the deformation layers 20 and 21 (arrows in the deformation layers 20 and 21). That is, the deformation layers 20 and 21 alleviate the difference in linear expansion coefficient between the substrates 10 and 11 and the information recording layer 30. Furthermore, the thickness of the deformation layers 20 and 21 shrinks substantially uniformly within the main surface of the deformation layers 20 and 21. Therefore, the information recording layer 30 isotropically expands in the thickness direction and the in-plane direction (see FIG. 8A). In particular, in the optical information recording medium 1, a space 50 is provided around the information recording layer 30.
  • swells in an in-plane direction is ensured.
  • the substrates 10 and 11 are not easily bent or bent.
  • the information recording layer 30 is isotropically deformed and is difficult to bend or twist.
  • the information recording layer 30 Even if the information recording layer 30 is cured and shrunk, a shearing stress in the direction opposite to that shown in FIG. 8A acts in the deformation layers 20 and 21 (arrows in the deformation layers 20 and 21). Furthermore, the thickness of the deformation layers 20 and 21 extends substantially uniformly within the main surface of the deformation layers 20 and 21. Therefore, the information recording layer 30 isotropically contracts in the thickness direction and the in-plane direction (see FIG. 8B). That is, even when the information recording layer 30 is cured and contracted, the optical information recording medium 1 is unlikely to bend or twist the substrates 10 and 11. As a result, the information recording layer 30 is difficult to bend or curl. In addition, even if the substrates 10 and 11 are forcibly bent or bent by an external force, the information recording layer 30 may be bent or bent due to the presence of the deformation layers 20 and 21. hard.
  • the optical information recording medium 1 Although the interval of the recorded interference fringes slightly changes in the page data (one page), the inclination of the interference fringes hardly changes.
  • the incident angle of the reference light, the interval between the wavelength and the interference fringe, and the angle can be matched to reproduce all of the page data (for one page).
  • the reproduced data is shown in FIG. As shown in the figure, the luminance signal of the reproduced information light is reproduced over the entire area of the page data (for one page).
  • the deformable layers 20 and 21 When the thickness of the deformable layers 20 and 21 is smaller than 10 ⁇ m, the deformable layers 20 and 21 are difficult to hold shear stress therein. Thereby, the information recording layer 30 becomes difficult to expand and contract isotropically in the thickness direction and the in-plane direction, and may be bent or bent.
  • the thickness of the deformable layers 20 and 21 is larger than 500 ⁇ m, the capacity of the deformable layers 20 and 21 is increased, and the deformable layers 20 and 21 themselves are easily bent. Thereby, the information recording layer 30 may bend or curl.
  • the above-described shear stress can be evenly distributed above and below the information recording layer 30.
  • the information recording layer 30 expands and contracts isotropically in the thickness direction and the in-plane direction.
  • the difference in the linear expansion coefficient between the substrates 10 and 11 and the information recording layer 30 is alleviated by the deformation layers 20 and 21. Thereby, the temperature difference during recording and reproduction, and the degradation of the reproduced image due to curing shrinkage are suppressed. That is, a more reliable optical information recording medium is realized.
  • the optical information recording medium 1 it is not necessary to approximate the linear expansion coefficient of the substrates 10 and 11 and the linear expansion coefficient of the information recording layer 30. Accordingly, with respect to the substrates 10 and 11 and the information recording layer 30, the degree of freedom in selecting other characteristics (for example, light transmittance, refractive index, birefringence, hardness, etc.) other than the linear expansion coefficient is expanded. As a result, the degree of freedom of material selection related to the optical information recording medium 1 is greatly improved. Further, in the optical information recording medium 1, the interference fringes are difficult to tilt even if a temperature difference occurs. Thereby, even if the information recording layer 30 is thick and the NA of the lens through which the information light passes is configured to be large, it is easy to reproduce the luminance signal of the entire page data.
  • other characteristics for example, light transmittance, refractive index, birefringence, hardness, etc.
  • FIG. 9 is a schematic diagram of a main part of an optical information recording medium.
  • 9A shows the top surface of the main part of the optical information recording medium 2
  • FIGS. 9B and 9C show the XY cross section of FIG. 9A.
  • a space 50 is provided in the optical information recording medium 1 described above, but such a space is not provided in the optical information recording medium 2.
  • the linear expansion coefficient of the spacer 40 is larger than the linear expansion coefficient of the substrates 10 and 11.
  • the material of the spacer 40 is, for example, a fluorocarbon resin such as Teflon (registered trademark).
  • the degree of freedom that the information recording layer 30 expands in the in-plane direction is ensured. That is, even if a temperature difference occurs in the optical information recording medium 2, the substrates 10 and 11 are not easily bent or bent. As a result, the information recording layer 30 is difficult to bend or curl. Also in such an optical information recording medium 2, the same effect as the optical information recording medium 1 can be obtained.
  • FIG. 10 is a schematic diagram of a main part of an optical information recording medium.
  • FIG. 10A shows the top surface of the main part of the optical information recording medium 3, and
  • FIG. 10B shows the XY cross section of FIG. 10A.
  • the spacer 40 is made of the same material as the substrates 10 and 11. Further, the spacer 40 is configured integrally with at least one of the substrate 10 and the substrate 10.
  • FIG. 10B shows a structure in which the substrate 11 and the spacer 40 are integrated as an example.
  • an optical information recording medium 3 Even in such an optical information recording medium 3, the same effect as the optical information recording medium 1 can be obtained.
  • the substrate 11 and the spacer 40 can be manufactured integrally, an optical information recording medium can be manufactured at a lower cost.
  • FIG. 11 is a schematic diagram of a main part of an optical information recording medium.
  • FIG. 11A shows the top surface of the main part of the optical information recording medium 4, and
  • FIG. 11B shows the XY cross section of FIG. 11A.
  • a spherical support member 60 having a diameter substantially the same as the thickness of the deformation layers 20, 21 is disposed in the deformation layers 20, 21.
  • the support member 60 may be arranged in a lattice shape as shown in FIG. 11A, or may be arranged in a honeycomb shape.
  • the refractive index and transmittance of the support member 60 are preferably substantially the same as or similar to the refractive index and transmittance of the deformable layers 20 and 21. Thereby, the layer including the deformable layers 20 and 21 and the support member 60 is apparently optically homogeneous.
  • Examples of the material of the support member 60 include glass and organic resin.
  • the information recording layer 30 is supported from above and below by the support member 60 in addition to the deformable layers 20 and 21. That is, the information recording layer 30 according to the optical information recording medium 4 is more difficult to bend and more difficult to bend than the information recording layer 30 of the optical information recording medium 1. In this case, the information recording layer 30 other than the portion where the support member 60 and the information recording layer 30 are in contact can expand and contract isotropically.
  • the optical information recording medium 4 can reproduce the page data more stably than the optical information recording medium 1.
  • the shape of the support member 60 may be a cubic shape, a columnar shape, a cylindrical shape, a conical shape, a kamaboko shape, or the like.
  • the support member 60 and the substrates 10 and 11 may be integrally formed.
  • the portion where the support member 60 is disposed may be hollow.
  • FIG. 12 is a schematic diagram of a main part of an optical information recording medium.
  • FIG. 12A shows the top surface of the main part of the optical information recording medium 5
  • FIG. 12B shows the XY cross section of FIG. 12A.
  • the shape of the main surface is a disk shape, and a central axis 70 is provided at the center.
  • a spacer 71 is provided around the central axis 70.
  • the optical information recording medium 5 rotates around the central axis 70. With such a structure, the optical information recording medium 5 can be used as a so-called disk type recording medium.
  • FIG. 13 is a schematic diagram of a main part of an optical information recording medium.
  • FIG. 13 (a) shows the top surface of the main part of the optical information recording medium 6, and
  • FIG. 13 (b) shows the XY cross section of FIG. 13 (a).
  • a space 50 is provided in the information recording layer 30 in addition to the outer periphery of the information recording layer 30.
  • the information recording layer 30 is divided into individual information recording layers 30 a with a space 50 therebetween.
  • each information recording layer 30a expands and contracts in the in-plane direction is further improved.
  • the degree of freedom that the information recording layer 30 expands and contracts isotropically is further improved.
  • the optical information recording medium 6 can reproduce the page data more stably than the optical information recording medium 1.
  • the position of the space 50 in the information recording layer 30 is not limited to the position shown in FIG. For example, it may be provided at the center of the optical information recording medium 6.
  • the shape of the main surface of each information recording layer 30a is not necessarily rectangular, and may be a circular shape or a polygonal shape other than a square shape.
  • the information recording layer 30 is obtained by changing the thickness of the deformable layers 20 and 21 in a direction substantially parallel to the main surfaces of the deformable layers 20 and 21 and changing the thickness thereof substantially uniformly in the main surfaces of the deformable layers 20 and 21.
  • a form in which these are not matched is also included in the present embodiment as long as the reproduction degradation of the image is allowable.
  • a more reliable optical information recording medium is provided without deteriorating the degree of freedom of material selection.

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Abstract

Provided is an optical information recording medium having information recorded thereon and reproduced therefrom as hologram. The optical information recording medium is provided with: a first substrate; a second substrate facing the first substrate; an information recording layer sandwiched between the first substrate and the second substrate; a first deformation layer arranged between the first substrate and the information recording layer; and a second deformation layer arranged between the second substrate and the information recording layer.

Description

光情報記録媒体Optical information recording medium
　本発明は、光情報記録媒体に関し、特に、情報をホログラムとして記録再生する光情報記録媒体に関する。 The present invention relates to an optical information recording medium, and more particularly to an optical information recording medium for recording and reproducing information as a hologram.
　近年、高密度の記録媒体として、情報をホログラムとして記録再生する光情報記録媒体（ホログラフィックメモリ）が注目されている。　
　この光情報記録媒体は、体積記録方式の媒体であるために、面記録方式のＤＶＤ（Digital Versatile Disk）などに比べて大きな記録密度を有する。また、ＤＶＤなどの場合、記録マークは一般にＯＮ／ＯＦＦのビットデータで表される。これに対し、ホログラフィックメモリでは、大量の情報が一括して変調されて干渉縞として記録される。この情報は、白黒のドットで構成された２次元バーコード状の記録再生データを単位とし、ページデータと呼ばれる。 In recent years, optical information recording media (holographic memory) that record and reproduce information as holograms have attracted attention as high-density recording media.
Since this optical information recording medium is a volume recording medium, it has a higher recording density than a surface recording DVD (Digital Versatile Disk) or the like. In the case of a DVD or the like, the recording mark is generally represented by ON / OFF bit data. On the other hand, in a holographic memory, a large amount of information is modulated at once and recorded as interference fringes. This information is called page data in units of two-dimensional barcode-like recording / playback data composed of black and white dots.
　ホログラフィックメモリの記録密度を増大する方法の一つに、多重記録方式がある。この多重記録方式は、ホログラフィックメモリの同一場所に複数のページデータを記録する方式である。例えば、レーザ光の照射角度をずらす角度多重記録、レーザ光の照射位置を僅かにずらすシフト多重記録などである。さらに情報光と参照光との干渉方法についても、情報光と参照光を別々の光束として媒体に入射して干渉させる二光束干渉方式、情報光と参照光を同一の対物レンズを通過させて干渉させるコアキシャル方式などがある。いずれの多重方式、干渉方法に従っても、ホログラフィックメモリの情報記録層には干渉縞が記録される。情報記録層は、一対の基板によってサンドイッチ状に挟まれている。 One method for increasing the recording density of a holographic memory is a multiple recording method. This multiple recording method is a method of recording a plurality of page data in the same location of the holographic memory. For example, angle multiplex recording in which the laser beam irradiation angle is shifted, shift multiplex recording in which the laser beam irradiation position is slightly shifted, and the like. As for the interference method between the information beam and the reference beam, the information beam and the reference beam are incident on the medium as separate beams and interfere with each other. The information beam and the reference beam are interfered by passing through the same objective lens. There is a coaxial method to let you. Regardless of the multiplexing method or interference method, interference fringes are recorded on the information recording layer of the holographic memory. The information recording layer is sandwiched between a pair of substrates.
　ところが、記録時の温度と再生時の温度に差がある場合には、再生像が劣化する場合がある。この現象は、基板と情報記録層との線膨張係数の差によるものと考えられている（例えば、非特許文献１参照）。このような再生劣化は、情報記録層を形成する際に、その材料である記録材料を硬化する際の収縮（硬化収縮）によっても引き起こされる。　
　これに対して、基板および情報記録層の線膨張係数の差を小さくする方法がある（例えば、特許文献１参照）。この方法では、情報記録層の厚さを１０～１１ミクロンとし、基板および情報記録層の線膨張係数の差と、記録時と再生時の温度差の積の絶対値が１／１００以下であれば干渉縞の乱れは起き難いとしている。　
　しかしながら、線膨張係数の差を小さくしつつ、線膨張係数以外の他の特性について充分なものを得ようとすると、光情報記録媒体の材料選択の自由度が損なわれてしまう。 However, if there is a difference between the temperature during recording and the temperature during reproduction, the reproduced image may deteriorate. This phenomenon is considered to be due to a difference in linear expansion coefficient between the substrate and the information recording layer (see, for example, Non-Patent Document 1). Such reproduction deterioration is also caused by shrinkage (curing shrinkage) when the recording material as the material is cured when the information recording layer is formed.
On the other hand, there is a method for reducing the difference in linear expansion coefficient between the substrate and the information recording layer (see, for example, Patent Document 1). In this method, the thickness of the information recording layer is 10 to 11 microns, and the absolute value of the product of the difference between the linear expansion coefficients of the substrate and the information recording layer and the temperature difference between recording and reproduction is 1/100 or less. The disturbance of interference fringes is unlikely to occur.
However, if an attempt is made to obtain sufficient characteristics other than the linear expansion coefficient while reducing the difference between the linear expansion coefficients, the degree of freedom in selecting the material of the optical information recording medium is impaired.
特開平５－１６５３８８号公報JP-A-5-165388
　本発明の目的は、材料選択の自由度を損なうことなく、より信頼性の高い光情報記録媒体を提供することにある。 An object of the present invention is to provide a more reliable optical information recording medium without impairing the freedom of material selection.
　本発明の一態様によれば、情報をホログラムとして記録再生する光情報記録媒体であって、第１の基板と、前記第１の基板に対向する第２の基板と、前記第１の基板と前記第２の基板との間に挟まれた情報記録層と、前記第１の基板と前記情報記録層との間に設けられた第１の変形層と、前記第２の基板と前記情報記録層との間に設けられた第２の変形層と、を備えたことを特徴とする光情報記録媒体が提供される。 According to one aspect of the present invention, there is provided an optical information recording medium that records and reproduces information as a hologram, and includes a first substrate, a second substrate facing the first substrate, and the first substrate. An information recording layer sandwiched between the second substrate, a first deformation layer provided between the first substrate and the information recording layer, the second substrate and the information recording There is provided an optical information recording medium comprising: a second deformation layer provided between the layers.
　本発明によれば、材料選択の自由度が損なわず、より信頼性の高い光情報記録媒体が実現する。 According to the present invention, a more reliable optical information recording medium is realized without impairing the freedom of material selection.
光情報記録媒体の要部模式図である。It is a principal part schematic diagram of an optical information recording medium. 変形層の厚さとヤング率との関係を説明する図である。It is a figure explaining the relationship between the thickness of a deformation | transformation layer, and Young's modulus. ヤング率と、硬度および針入度との換算を説明するための図である。It is a figure for demonstrating conversion of a Young's modulus, hardness, and penetration. 光情報記録媒体の製造工程のフロー図である。It is a flowchart of the manufacturing process of an optical information recording medium. 光情報記録媒体の動作原理を説明する図である。It is a figure explaining the principle of operation of an optical information recording medium. 光情報記録媒体の模式図およびページデータの再生像を説明する図である。It is a figure explaining the reproduction image of the schematic diagram and page data of an optical information recording medium. 光情報記録媒体の模式図およびページデータの再生像を説明する図である。It is a figure explaining the reproduction image of the schematic diagram and page data of an optical information recording medium. 光情報記録媒体の模式図およびページデータの再生像を説明する図である。It is a figure explaining the reproduction image of the schematic diagram and page data of an optical information recording medium. 光情報記録媒体の要部模式図である。It is a principal part schematic diagram of an optical information recording medium. 光情報記録媒体の要部模式図である。It is a principal part schematic diagram of an optical information recording medium. 光情報記録媒体の要部模式図である。It is a principal part schematic diagram of an optical information recording medium. 光情報記録媒体の要部模式図である。It is a principal part schematic diagram of an optical information recording medium. 光情報記録媒体の要部模式図である。It is a principal part schematic diagram of an optical information recording medium.
　以下、図面を参照しつつ、実施の形態について説明する。 Hereinafter, embodiments will be described with reference to the drawings.
　図１は、光情報記録媒体の要部模式図である。図１（ａ）には、光情報記録媒体１の要部上面が示され、図１（ｂ）には、図１（ａ）のＸ－Ｙ断面が示されている。　
　光情報記録媒体１は、情報をホログラムとして記録再生する光情報記録媒体（ホログラフィックメモリ、ホログラム記録媒体）である。光情報記録媒体１は、対向する基板１０および基板１１と、基板１０と基板１１との間に挟まれた情報記録層３０と、基板１０と情報記録層３０との間に設けられた変形層２０と、基板１１と情報記録層３０との間に設けられた変形層２１と、を備える。 FIG. 1 is a schematic diagram of a main part of an optical information recording medium. FIG. 1 (a) shows the top surface of the main part of the optical information recording medium 1, and FIG. 1 (b) shows the XY cross section of FIG. 1 (a).
The optical information recording medium 1 is an optical information recording medium (holographic memory, hologram recording medium) that records and reproduces information as a hologram. The optical information recording medium 1 includes an opposing substrate 10 and substrate 11, an information recording layer 30 sandwiched between the substrate 10 and the substrate 11, and a deformation layer provided between the substrate 10 and the information recording layer 30. 20 and a deformation layer 21 provided between the substrate 11 and the information recording layer 30.
　対向する基板１０、１１は平坦状であり、その内側に平坦状の変形層２０、２１が設けられている。変形層２０と変形層２１とは互いに対向する。変形層２０と変形層２１との間には、情報記録層３０が挟まれている。基板１０の両端部１０ｔと基板１１の両端部１１ｔとの間には、リング状のスペーサ４０が設けられている。スペーサ４０は、対向する基板１０、１１の間に設けられるので、光情報記録媒体１の厚みを規定することができる。 The opposing substrates 10 and 11 are flat, and flat deformation layers 20 and 21 are provided inside thereof. The deformation layer 20 and the deformation layer 21 face each other. An information recording layer 30 is sandwiched between the deformation layer 20 and the deformation layer 21. Ring-shaped spacers 40 are provided between both end portions 10 t of the substrate 10 and both end portions 11 t of the substrate 11. Since the spacer 40 is provided between the opposing substrates 10 and 11, the thickness of the optical information recording medium 1 can be defined.
　変形層２０、２１および情報記録層３０と、スペーサ４０と、の間には、空間５０が設けられている。これにより、情報記録層３０の周囲には、基板１０と基板１１とに間に自由空間が形成される。 A space 50 is provided between the deformation layers 20 and 21 and the information recording layer 30 and the spacer 40. As a result, a free space is formed between the substrate 10 and the substrate 11 around the information recording layer 30.
　このように、光情報記録媒体１では、情報記録層３０および変形層２０、２１は、基板１０、１１およびスペーサ４０により封止されている。　
　なお、スペーサ４０を設けずとも、光情報記録媒体１の厚さ、基板１０、１１間の平行度、基板１０、１１の強度、情報記録層３０および変形層２０、２１の密封性が保たれるのであれば、スペーサ４０については適宜取り除いてもよい。スペーサ４０の代わりに、不透明な接着部材、充填部材を用いてもよい。基板１０、１１の内側には、凹凸形状（トラック）、ダイクロイックミラー、反射層などを設けてもよい。 As described above, in the optical information recording medium 1, the information recording layer 30 and the deformation layers 20 and 21 are sealed by the substrates 10 and 11 and the spacer 40.
Even if the spacer 40 is not provided, the thickness of the optical information recording medium 1, the parallelism between the substrates 10 and 11, the strength of the substrates 10 and 11, and the sealing performance of the information recording layer 30 and the deformation layers 20 and 21 are maintained. If necessary, the spacer 40 may be removed as appropriate. Instead of the spacer 40, an opaque adhesive member or filling member may be used. An uneven shape (track), a dichroic mirror, a reflective layer, and the like may be provided inside the substrates 10 and 11.
　次に、光情報記録媒体１の各部材の材料、特性、寸法等について説明する。　
　基板１０、１１の材質は、例えば、無機ガラス、ポリカーボネート、ポリメタクリル酸メチル樹脂などの樹脂が該当する。基板１０、１１の材質は、これらに限られるものではない。例えば、基板１０、１１の材質は、記録再生に用いられる光に対して充分な透過率を有し、複屈折率が小さいなどの良好な光学的条件を有し、且つ光記録媒体としての充分な強度を保持できるものであればよい。 Next, materials, characteristics, dimensions, etc. of each member of the optical information recording medium 1 will be described.
Examples of the material of the substrates 10 and 11 include resins such as inorganic glass, polycarbonate, and polymethyl methacrylate resin. The materials of the substrates 10 and 11 are not limited to these. For example, the materials of the substrates 10 and 11 have sufficient optical conditions such as a sufficient transmittance for light used for recording and reproduction, a low birefringence, and the like as an optical recording medium. What is necessary is just to be able to maintain a sufficient strength.
　なお、基板１０、１１においては、記録再生の手段によっては、基板１０、１１のどちらか一方が充分な透過率を保持していればよい。また、光が入射・出射する基板１０、１１の主面に、反射防止膜（ＡＲコート）を施してもよい。 It should be noted that, in the substrates 10 and 11, it is sufficient that either one of the substrates 10 and 11 has a sufficient transmittance depending on the recording / reproducing means. Further, an antireflection film (AR coating) may be applied to the main surfaces of the substrates 10 and 11 on which light enters and exits.
　情報記録層３０の材質は、例えば、フォトポリマが該当する。ここで、フォトポリマは、重合性化合物（モノマ）の光重合を利用した感光材料である。フォトポリマの主成分は、重合性化合物、光重合開始剤、および記録前後での体積保持の役割を担う多孔質状のマトリックスを含有する。　
　具体的には、情報記録層３０は、三次元架橋ポリマーマトリックス、光ラジカル重合開始剤、およびラジカルによって開環重合する脂肪族環状構造を有する開環重合性化合物を含有する。 The material of the information recording layer 30 corresponds to, for example, a photopolymer. Here, the photopolymer is a photosensitive material using photopolymerization of a polymerizable compound (monomer). The main component of the photopolymer contains a polymerizable compound, a photopolymerization initiator, and a porous matrix that plays a role of volume retention before and after recording.
Specifically, the information recording layer 30 contains a three-dimensional cross-linked polymer matrix, a photo radical polymerization initiator, and a ring-opening polymerizable compound having an aliphatic cyclic structure that undergoes ring-opening polymerization by radicals.
　開環重合性化合物は、例えば、ビニルシクロプロパン化合物、環状スルフィド化合物、ビシクロブタン化合物、ビニル環状ブタン化合物、ビニル環状スルホン化合物、環状ケテンアセタール化合物、メチレンジオキソラン化合物、環状アリルスルフィド化合物、ベンゾシクロブテン化合物、キシリレンダイマー化合物、および環状ジスルフィド化合物などが該当する。 Ring-opening polymerizable compounds include, for example, vinylcyclopropane compounds, cyclic sulfide compounds, bicyclobutane compounds, vinyl cyclic butane compounds, vinyl cyclic sulfone compounds, cyclic ketene acetal compounds, methylene dioxolane compounds, cyclic allyl sulfide compounds, benzocyclobutene compounds. , Xylylene dimer compounds, and cyclic disulfide compounds.
　開環重合性化合物の脂肪族環状構造は、環状スルフィド構造、ビシクロブタン構造、ビニルシクロプロパン構造、ビニル環状スルホン構造、４－メチレン－１，３－ジオキソラン構造、環状ケテンアセタール構造、８－メチレン－１，４－ジオキサスピロ－［４．５］デカ－６，９－ジエン構造、環状アリルスルフィド構造、環状α－オキシアクリル酸エステル構造、ベンゾシクロブテン構造、ｏ－キシリレンダイマー構造、エキソメチレン構造とスピロオルトカーボネート構造とを分子内に有する構造、およびエキソメチレン構造とスピロオルトエステル構造とを分子内に有する構造からなる群から選択される。あるいは、脂肪族環状構造は、１－シクロプロピル－１－フェニルエテン、１－シクロプロピル－１－トリブロモフェニルエテン、および１－シクロプロピル－１－ナフチルエテンからなる群から選択される。 The aliphatic ring structure of the ring-opening polymerizable compound includes cyclic sulfide structure, bicyclobutane structure, vinylcyclopropane structure, vinyl cyclic sulfone structure, 4-methylene-1,3-dioxolane structure, cyclic ketene acetal structure, 8-methylene- 1,4-dioxaspiro- [4.5] deca-6,9-diene structure, cyclic allyl sulfide structure, cyclic α-oxyacrylate structure, benzocyclobutene structure, o-xylylene dimer structure, exomethylene structure It is selected from the group consisting of a structure having a spiroorthocarbonate structure in the molecule and a structure having an exomethylene structure and a spiroorthoester structure in the molecule. Alternatively, the aliphatic cyclic structure is selected from the group consisting of 1-cyclopropyl-1-phenylethene, 1-cyclopropyl-1-tribromophenylethene, and 1-cyclopropyl-1-naphthylethene.
　三次元架橋ポリマーマトリックスは、エポキシモノマを、エポキシ－アミン重合、エポキシ－酸無水物重合、またはエポキシホモ重合により重合することにより得られる。　光ラジカル重合開始剤は、イミダゾール誘導体、有機アジド化合物、チタノセン類、有機過酸化物、およびチオキサントン誘導体からなる群から選択される。　
　情報記録層３０の材質は、これらに限定されるものではない。例えば、情報記録層３０の材質として、重クロム酸ゼラチン、フォトリフラクティブ結晶などを用いてもよい。 A three-dimensional cross-linked polymer matrix is obtained by polymerizing an epoxy monomer by epoxy-amine polymerization, epoxy-acid anhydride polymerization, or epoxy homopolymerization. The radical photopolymerization initiator is selected from the group consisting of imidazole derivatives, organic azide compounds, titanocenes, organic peroxides, and thioxanthone derivatives.
The material of the information recording layer 30 is not limited to these. For example, dichromated gelatin, photorefractive crystal, or the like may be used as the material of the information recording layer 30.
　情報記録層３０の厚さは、信号再生に充分な回折効率と、角度多重の際に充分な角度分解能が得られる程度であればよい。例えば、本実施の形態に係る情報記録層３０の厚さは、１００μｍ以上、より好ましくは１ｍｍ以上であることが望ましく、１００μｍ以上、２ｍｍ以下であることが望ましい。なお、情報記録層３０の記録密度に応じて、適宜、情報記録層３０の厚みを変えてよい。 The thickness of the information recording layer 30 only needs to be sufficient to obtain a diffraction efficiency sufficient for signal reproduction and a sufficient angle resolution in angle multiplexing. For example, the thickness of the information recording layer 30 according to the present embodiment is preferably 100 μm or more, more preferably 1 mm or more, and preferably 100 μm or more and 2 mm or less. Note that the thickness of the information recording layer 30 may be appropriately changed according to the recording density of the information recording layer 30.
　変形層２０、２１の材質は、物理的、化学的に安定な材料が用いられる。例えば、記録再生に利用される光を照射しても、物理的、化学的に変化しない材料が用いられる。また、情報記録層３０、基板１０、１１との界面で化学反応が起き難い材料が用いられる。変形層２０、２１の材質は、記録再生に利用される光に対して充分な透過率を有し、複屈折が小さいなどの光学的条件を具備する材料であれば、いかなる材（固体、ゲル等）であってもよい。 The material of the deformation layers 20 and 21 is a physically and chemically stable material. For example, a material that does not change physically and chemically even when irradiated with light used for recording and reproduction is used. Further, a material that does not easily cause a chemical reaction at the interface between the information recording layer 30 and the substrates 10 and 11 is used. The material of the deformable layers 20 and 21 is any material (solid, gel) as long as it has a sufficient transmittance for light used for recording and reproduction and has optical conditions such as low birefringence. Etc.).
　また、変形層２０と変形層２１とは、線膨張係数、厚さが同じであることが好ましい。これにより、対向する変形層２０と変形層２１に関し、温度変化に対する上層（変形層２０）と下層（変形層２１）での非対称的な変形を避けることができる。ただし、必要に応じて、変形層２０と変形層２１とを異なる材料、厚さとしてもよい。 Further, it is preferable that the deformation layer 20 and the deformation layer 21 have the same linear expansion coefficient and thickness. Thereby, regarding the deformation layer 20 and the deformation layer 21 which oppose, the asymmetric deformation | transformation in the upper layer (deformation layer 20) and lower layer (deformation layer 21) with respect to a temperature change can be avoided. However, if necessary, the deformable layer 20 and the deformable layer 21 may be made of different materials and thicknesses.
　変形層２０、２１の厚さは、１０μｍ～５００μｍであることが好ましい。変形層２０、２１の厚さが１０μｍより小さければ、変形層２０、２１は、情報記録層３０を等方的に伸縮させる機能を失うからである。変形層２０、２１の厚さが５００μｍより大きければ、変形層２０、２１自体が撓み易くなり、情報記録層３０を保持できる強度を有しないからである。 The thickness of the deformation layers 20 and 21 is preferably 10 μm to 500 μm. This is because if the thickness of the deformable layers 20 and 21 is smaller than 10 μm, the deformable layers 20 and 21 lose the function of expanding and contracting the information recording layer 30 isotropically. This is because if the thickness of the deformable layers 20 and 21 is larger than 500 μm, the deformable layers 20 and 21 themselves are easily bent and do not have the strength to hold the information recording layer 30.
　また、変形層２０、２１のヤング率は、情報記録層３０のヤング率の１／１０以下であることが好ましい。　
　特に、基板１０、１１の材質がガラス、ポリカーボネートなどの場合、その線膨張率は、情報記録層３０に比べて１ケタ以上小さくなる。従って、温度差による基板１０、１１と情報記録層３０との線膨張の違いを変形層２０、２１が緩和するには、変形層２０、２１のヤング率は、情報記録層３０のヤング率の１／１０以下が好ましい。 The Young's modulus of the deformation layers 20 and 21 is preferably 1/10 or less of the Young's modulus of the information recording layer 30.
In particular, when the materials of the substrates 10 and 11 are glass, polycarbonate, etc., the linear expansion coefficient is one digit or more smaller than that of the information recording layer 30. Therefore, in order for the deformation layers 20 and 21 to alleviate the difference in linear expansion between the substrates 10 and 11 and the information recording layer 30 due to the temperature difference, the Young's modulus of the deformation layers 20 and 21 is the Young's modulus of the information recording layer 30. 1/10 or less is preferable.
　具体的には、情報記録層３０がフォトポリマの場合、フォトポリマのヤング率は、１０６～１０７（Ｐａ）程度である。このヤング率を硬度（JISタイプＡ）に置き換えると、フォトポリマの硬度は、３０～８０（JISタイプＡ）程度である。 Specifically, when the information recording layer 30 is a photopolymer, the Young's modulus of the photopolymer is about 10 6 to 10 7 (Pa). When this Young's modulus is replaced with hardness (JIS type A), the hardness of the photopolymer is about 30 to 80 (JIS type A).
　従って、変形層２０、２１のヤング率は、１０５～１０６（Ｐａ）以下が好ましい。あるいは、変形層２０、２１の硬さを硬度（JISタイプＡ）または針入度（JIS K2220 1/4コーン）に置き換えると、硬度としては、３０（JIS タイフ゜A）以下であり、針入度としては、０（JIS K2220 1/4コーン）以上であることが好ましい。 Therefore, the Young's modulus of the deformation layers 20 and 21 is preferably 10 5 to 10 6 (Pa) or less. Alternatively, if the hardness of the deformable layers 20, 21 is replaced with hardness (JIS type A) or penetration (JIS K2220 1/4 cone), the hardness is 30 (JIS type A) or less, and the penetration is Is preferably 0 (JIS K2220 1/4 cone) or more.
　なお、代表的な有機樹脂であるポリイミド樹脂のヤング率は、約３．５（ＧＰａ）である。従って、変形層２０、２１のヤング率は、ポリイミド樹脂のヤング率に比べ、１／１００００～１／１０００以下である。 Note that the Young's modulus of polyimide resin, which is a typical organic resin, is about 3.5 (GPa). Accordingly, the Young's modulus of the deformable layers 20 and 21 is 1/10000 to 1/1000 or less than the Young's modulus of the polyimide resin.
　また、情報記録層３０のヤング率をＥｒ、変形層２０（あるいは、変形層２１）のヤング率をＥｔ、変形層２０（あるいは、変形層２１）の厚さをＴｔとしたときに、（Ｅｒ／Ｅｔ）×Ｔｔが１０（ｍｍ）以上であることがより好ましい。 When the Young's modulus of the information recording layer 30 is Er, the Young's modulus of the deformable layer 20 (or deformable layer 21) is Et, and the thickness of the deformable layer 20 (or deformable layer 21) is Tt, (Er / Et) × Tt is more preferably 10 (mm) or more.
　例えば、図２には、変形層の厚さ（Ｔｔ）とＥｒ／Ｅｔの関係が示されている。ここで、図２の横軸には、厚さＴｔ（ｍｍ）が示され、縦軸には、（Ｅｒ／Ｅｔ）が示されている。　ここで、（Ｅｒ／Ｅｔ）×Ｔｔ≧１０（ｍｍ）の条件は、図中の曲線Ａから上方の領域において達成され得る。 For example, FIG. 2 shows the relationship between the thickness (Tt) of the deformed layer and Er / Et. Here, the horizontal axis of FIG. 2 indicates the thickness Tt (mm), and the vertical axis indicates (Er / Et). Here, the condition of (Er / Et) × Tt ≧ 10 (mm) can be achieved in the region above the curve A in the figure.
　例えば、変形層２０（あるいは、変形層２１）の厚みが薄くなっても、（Ｅｒ／Ｅｔ）が曲線Ａ上の値より大きければ、情報記録層３０の歪みが変形層２０、２１により充分に緩和される。 For example, even if the thickness of the deformable layer 20 (or the deformable layer 21) is reduced, if (Er / Et) is larger than the value on the curve A, the distortion of the information recording layer 30 is more sufficiently caused by the deformable layers 20 and 21. Alleviated.
　このように、変形層２０、２１は、情報記録層３０よりも柔らかく、情報記録層３０を保持する強度を有する。　
　なお、ヤング率と、硬度（JIS タイプＡ）とは、図３に示す換算表により換算される（東レ・ダウコーニング社、エレクトロニクスシリコーンカタログ参照）。なお、この図には、硬さの指標である針入度（JIS K2220 1/4コーン）が表示されている。 As described above, the deformation layers 20 and 21 are softer than the information recording layer 30 and have strength to hold the information recording layer 30.
The Young's modulus and hardness (JIS type A) are converted according to the conversion table shown in FIG. 3 (see Toray Dow Corning Electronics Silicone Catalog). In this figure, the penetration (JIS K2220 1/4 cone), which is an index of hardness, is displayed.
　また、変形層２０、２１の光透過率は、高いほどよい。例えば、変形層２０もしくは変形層２１の光透過率は、８７％以上あることが好ましい。これにより、再生の際に光情報記録媒体１を透過した参照光をミラーで反射して反対方向から再度媒体に入射するいわゆる位相共役再生を行う場合にも再生光強度の低下を５０％以内におさめることができる。なお、光を光情報記録媒体１に入射した後の光散乱は、小さければより好ましい。 Also, the higher the light transmittance of the deformable layers 20, 21, the better. For example, the light transmittance of the deformation layer 20 or the deformation layer 21 is preferably 87% or more. Thus, even when performing so-called phase conjugate reproduction in which the reference light transmitted through the optical information recording medium 1 during reproduction is reflected by a mirror and incident on the medium again from the opposite direction, the reproduction light intensity is reduced to within 50%. I can stop you. The light scattering after the light is incident on the optical information recording medium 1 is preferably as small as possible.
　また、変形層２０、２１の複屈折率は、より低いほうが好ましい。変形層２０、２１を通過する通常光線の屈折率（Ｎｅ）と異常光線の屈折率（Ｎｏ）は、ともに基板１０、１１の屈折率と情報記録層３０の屈折率の間にあれば、変形層２０、２１自体による複屈折は問題とならない。 Further, the birefringence of the deformation layers 20 and 21 is preferably lower. If the refractive index (Ne) of ordinary light passing through the deformation layers 20 and 21 and the refractive index (No) of extraordinary light are both between the refractive index of the substrates 10 and 11 and the refractive index of the information recording layer 30, the deformation will occur. Birefringence due to the layers 20 and 21 itself is not a problem.
　例えば、基板１０、１１の屈折率の最大値をＮＳ１、最小値をＮＳ２、情報記録層３０の屈折率の最大値をＮＲ１、最小値をＮＲ２とする。この際、ＮＳ１＞Ｎｅ＞ＮＲ２、且つＮＳ１＞Ｎｏ＞ＮＲ２、もしくは、ＮＳ２＜Ｎｅ＜ＮＲ１、且つＮＳ２＜Ｎｏ＜ＮＲ１であれば、変形層２０、２１自体による複屈折は問題とならない。 For example, the maximum value of the refractive index of the substrates 10 and 11 is N S1 , the minimum value is N S2 , the maximum value of the refractive index of the information recording layer 30 is N R1 , and the minimum value is N R2 . At this time, if N S1 >Ne> N R2 and N S1 >No> N R2 , or N S2 <Ne <N R1 and N S2 <No <N R1 , then the deformation layers 20 and 21 themselves are combined. Refraction does not matter.
　また、本実施の形態では、基板１０と変形層２０との界面、基板１１と変形層２１との界面、変形層２０と情報記録層３０との界面、変形層２１と情報記録層３０との界面において、光の反射が起き難い材料が選定される。特に、基板１０と変形層２０との界面、基板１１と変形層２１との界面、変形層２０と情報記録層３０との界面、変形層２１と情報記録層３０との界面において、屈折率の差がゼロに近ければ、これらの界面での光の反射は生じ難い。それぞれの界面における屈折率の差が１０％以内であっても実用上問題はない。また、それぞれの界面における屈折率の差が１０％以上であっても、反射率は、数％以下であり実用上問題はない。 In the present embodiment, the interface between the substrate 10 and the deformation layer 20, the interface between the substrate 11 and the deformation layer 21, the interface between the deformation layer 20 and the information recording layer 30, and the deformation layer 21 and the information recording layer 30. A material that does not easily reflect light at the interface is selected. In particular, at the interface between the substrate 10 and the deformation layer 20, the interface between the substrate 11 and the deformation layer 21, the interface between the deformation layer 20 and the information recording layer 30, and the interface between the deformation layer 21 and the information recording layer 30. If the difference is close to zero, light reflection at these interfaces is unlikely. There is no practical problem even if the difference in refractive index at each interface is within 10%. Moreover, even if the difference in refractive index at each interface is 10% or more, the reflectance is several% or less, and there is no practical problem.
　変形層２０、２１の具体的な材質としては、例えば、（１）シリコーンゲル、シリコーンゴムなどのシリコーン樹脂、（２）アクリル系ゴム、アクリロニトリルブタジエン系ゴム、イソプレン系ゴム、ウレタン系ゴム、エチレンプロピレン系ゴム、クロロプレン系ゴム、ブタジエン系ゴム、スチレンブタジエン系ゴムの群から選択されるいずれかの合成ゴム、（３）アクリロニトリル・塩素化ポリエチレン・スチレン共重合体樹脂（Acrylonitrile Chlorinated polyethylene Styrene，ＡＣＳ）等の三元系共重合熱可塑性樹脂、（４）サーモトロピック型（熱溶融型）、若しくはリオトロピック型（溶液型）の液晶ポリマ、（５）オレフィン系、スチレン系、塩化ビニル系、ポリエステル系、ポリアミド系の群から選択されるいずれかの熱可塑性エラストマ、（６）エポキシ樹脂等が該当する。 Specific materials for the deformable layers 20 and 21 include, for example, (1) silicone resins such as silicone gel and silicone rubber, (2) acrylic rubber, acrylonitrile butadiene rubber, isoprene rubber, urethane rubber, and ethylene propylene. Synthetic rubber selected from the group of rubber, chloroprene rubber, butadiene rubber, styrene butadiene rubber, (3) acrylonitrile / chlorinated polyethylene / styrene copolymer resin (Acrylonitrile Chlorinated polyethylene Styrene, ACS), etc. (4) Thermotropic type (thermal melting type) or lyotropic type (solution type) liquid crystal polymer, (5) Olefin type, styrene type, vinyl chloride type, polyester type, polyamide Any thermoplastic elastomer selected from the group of systems M, (6) Epoxy resin, etc.
　より具体的には、変形層２０、２１の材質として、例えば、東レ・ダウコーニング社製のＪＣＲ６１０１、ＪＣＲ６１０１ＵＰ、ＪＣＲ６１２１、ＪＣＲ６１２２、ＪＣＲ６１１５、ＪＣＲ６１２５、ＪＣＲ６１２６、ＪＣＲ６１４０、ＪＣＲ６１７５、ＪＣＲ６１０９、ＪＣＲ６１１０、ＯＥ６２５０、Ｓｙｌｇａｒｄ１８４、ＳＥ１７４０、ＳＥ１８８６、ＳＥ１８９１Ｈ、ＳＥ１８９６ＦＲ、Ｓｙｌｇａｒｄ５２７、ＣＹ５２－２７６などが挙げられる。 More specifically, as the material of the deformation layers 20 and 21, for example, JCR6101, JCR6101UP, JCR6121, JCR6122, JCR6115, JCR6125, JCR6126, JCR6140, JCR6175, JCR6109, JCR6110, OE6250, Sylgard184, manufactured by Toray Dow Corning, Inc. SE1740, SE1886, SE1891H, SE1896FR, Sylgard527, CY52-276 and the like.
　あるいは、変形層２０、２１の材質として、モメンティブ・パフォーマンス・マテリアルズ社製のＩＶＳ５０２２、ＩＶＳ５３３２、ＸＥ１４-Ｃ２８６０、ＩＶＳ４０１２、ＩＶＳ４３１２、ＩＶＳ４５４２、ＴＳＪ３１５０、ＸＥ１４－Ｃ２０４２、ＸＥ１４－Ｂ５７７８１4－Ｂ５７７８、ＸＥ１３－Ｃ０８１０、ＩＶＳＭ４２００、ＩＶＳＭ４５００などが挙げられる。　
　スペーサ４０の材質は、例えば、テフロン（登録商標）等のフッ化炭素樹脂が該当する。 Alternatively, as the material of the deformation layers 20 and 21, IVS5022, IVS5332, XE14-C2860, IVS4012, IVS4312, IVS4542, TSJ3150, XE14-C2042, XE14-B577814-B5778, XE13-C0810, manufactured by Momentive Performance Materials, Inc. IVSM4200, IVSM4500, etc. are mentioned.
The material of the spacer 40 corresponds to, for example, a fluorocarbon resin such as Teflon (registered trademark).
　次に、光情報記録媒体１の製造方法について、図４に示すフロー図と、図１を参照しながら説明する。　
　まず、基板１０、１１を用意する（ステップＳ１０）。これらの基板１０、１１の主面には、反射防止膜を設けてもよい。 Next, a method for manufacturing the optical information recording medium 1 will be described with reference to the flowchart shown in FIG. 4 and FIG.
First, the substrates 10 and 11 are prepared (step S10). An antireflection film may be provided on the main surface of these substrates 10 and 11.
　次に、基板１０、１１の主面に、膜厚の均一性および表面の平坦性が良好な変形層２０、２１を形成する（ステップＳ２０）。このような変形層２０、２１は、予め、塗布法により基板１０、１１の主面に塗布層を形成した後、この塗布層を、例えば、自然硬化、加熱硬化、ＵＶ照射硬化などにより硬化して形成する。なお、塗布装置としては、例えば、スピンコータ、バーコータ、フィルムアプリケータなどを用いる。 Next, the deformation layers 20 and 21 having good film thickness uniformity and surface flatness are formed on the main surfaces of the substrates 10 and 11 (step S20). Such deformable layers 20 and 21 are previously formed on the main surfaces of the substrates 10 and 11 by a coating method, and then the coating layer is cured by, for example, natural curing, heat curing, UV irradiation curing, or the like. Form. In addition, as a coating device, a spin coater, a bar coater, a film applicator etc. are used, for example.
　次に、基板１０、１１間の距離を保持するためのスペーサ４０と、光情報記録媒体１の中心軸のチャッキング用ハブなどとともに、情報記録層３０を挟んで基板１０、１１を貼り合わせる（ステップＳ３０）。 Next, together with the spacer 40 for maintaining the distance between the substrates 10 and 11 and the chucking hub on the central axis of the optical information recording medium 1, the substrates 10 and 11 are bonded together with the information recording layer 30 interposed therebetween ( Step S30).
　このような方法により、光情報記録媒体１が形成される。なお、図１には、チャッキング用ハブは、図示されていない。　
　さらに必要に応じて、基板１０、１１の周囲をシール材で封止する（ステップＳ４０）。続いて、気泡混入検査などの欠陥検査を行う（ステップＳ５０）。さらに、シール材で封止した光情報記録媒体１を遮光カートリッジ内に組み込む（ステップＳ６０）。　
　なお、各製造工程での処理方法は、上述した形態に限定されるものではない。製造工程の順番も、適宜変更してもよい。 By such a method, the optical information recording medium 1 is formed. FIG. 1 does not show the chucking hub.
Furthermore, if necessary, the periphery of the substrates 10 and 11 is sealed with a sealing material (step S40). Subsequently, a defect inspection such as a bubble mixing inspection is performed (step S50). Further, the optical information recording medium 1 sealed with the sealing material is incorporated into the light shielding cartridge (step S60).
In addition, the processing method in each manufacturing process is not limited to the form mentioned above. The order of the manufacturing steps may be changed as appropriate.
　例えば、基板１０、１１を用意する際には、基板１０、１１の大きさを光情報記録媒体１の大きさとしてもよく、光情報記録媒体１よりも大きい基板１０、１１を用意してもよい。光情報記録媒体１よりも大きい基板１０、１１を用意した場合は、遮光カートリッジに組み込む前に、基板１０、１１を適当な大きさに分断すればよい。 For example, when preparing the substrates 10 and 11, the size of the substrates 10 and 11 may be the size of the optical information recording medium 1, or the substrates 10 and 11 larger than the optical information recording medium 1 may be prepared. Good. When the substrates 10 and 11 larger than the optical information recording medium 1 are prepared, the substrates 10 and 11 may be divided into appropriate sizes before being incorporated into the light shielding cartridge.
　情報記録層３０については、変形層２０を設けた基板１０と、変形層２１を設けた基板１１とを対向させた後、変形層２０と変形層２１との間に情報記録層３０の原材料を注入してもよい。この原材料については、自然硬化、加熱硬化、ＵＶ照射硬化などにより硬化する。 For the information recording layer 30, the substrate 10 provided with the deformable layer 20 and the substrate 11 provided with the deformable layer 21 face each other, and then the raw material of the information recording layer 30 is placed between the deformable layer 20 and the deformable layer 21. It may be injected. This raw material is cured by natural curing, heat curing, UV irradiation curing, or the like.
　次に、光情報記録媒体１の作用効果について、光情報記録媒体１と比較例とを対比しながら説明する。なお、比較例に係る光情報記録媒体には、光情報記録媒体１と同一の部材には同一の符号を付し、その詳細な説明については適宜省略する。 Next, the function and effect of the optical information recording medium 1 will be described while comparing the optical information recording medium 1 with a comparative example. In addition, the same code | symbol is attached | subjected to the member same as the optical information recording medium 1 in the optical information recording medium which concerns on a comparative example, and the detailed description is abbreviate | omitted suitably.
　図５は、光情報記録媒体の動作原理を説明する図である。ここで、記録媒体としては、光情報記録媒体１が示されている。記録方式としては、二光束干渉方式が示され、光情報記録媒体１のほか、情報光３１および参照光３２が示されている。 FIG. 5 is a diagram for explaining the operating principle of the optical information recording medium. Here, an optical information recording medium 1 is shown as the recording medium. As the recording method, a two-beam interference method is shown, and in addition to the optical information recording medium 1, information light 31 and reference light 32 are shown.
　光情報記録媒体１への情報の記録は、例えば、波長が４０５ｎｍの情報光３１および参照光３２とを、情報記録層３０中の同一個所に照射する。その際に情報光３１と参照光３２との交差によってできる光の干渉縞が情報記録層３０に記録される。　
　情報光３１は、例えば、液晶素子、デジタル・マイクロミラー・デバイス等の空間変調器（SLM：Spatial Light Modulator）によってレーザ光を空間的に変調して情報を有している（図示しない）。参照光３２は、情報光と同一波長で情報光と同一光源から生成される。 Information is recorded on the optical information recording medium 1 by, for example, irradiating the information recording layer 30 with the information light 31 and the reference light 32 having a wavelength of 405 nm. At this time, light interference fringes generated by the intersection of the information light 31 and the reference light 32 are recorded in the information recording layer 30.
The information light 31 has information (not shown) by spatially modulating the laser light with a spatial light modulator (SLM) such as a liquid crystal element or a digital micromirror device. The reference light 32 is generated from the same light source as the information light at the same wavelength as the information light.
　光情報記録媒体１の情報の再生の際には、参照光３２のみを情報記録層３０の記録部分に照射することにより、記録時の情報光が再現され、記録時に変調した情報（例えば、ページデータ）を取得することができる。 When reproducing information from the optical information recording medium 1, only the reference light 32 is irradiated onto the recording portion of the information recording layer 30, thereby reproducing the information light at the time of recording and modulating information (for example, page Data).
　図６～図８には、光情報記録媒体の模式図およびページデータ（１ページ分）の再生像が示されている。ここで、ページデータとは、２次元的に配列したバイナリーデータである。すなわち、情報光の輝度が２値のバイナリーデータに対応して変調され、情報記録層３０に記録される。　
　まず、図６（ａ）には、比較例１００に係る光情報記録媒体の構造が示され、図６（ｂ）には、比較例１００のページデータの再生像が示されている。 6 to 8 show schematic diagrams of the optical information recording medium and reproduced images of page data (for one page). Here, the page data is binary data arranged two-dimensionally. That is, the luminance of the information light is modulated corresponding to binary binary data and recorded on the information recording layer 30.
First, FIG. 6A shows the structure of an optical information recording medium according to Comparative Example 100, and FIG. 6B shows a reproduction image of page data of Comparative Example 100.
　比較例１００では、基板１０、１１が情報記録層３０に直接接触し、変形層２０、２１が設けられていない。ここで、情報記録層３０の厚みは、１ｍｍである。記録時と再生時における光情報記録媒体の温度差（ΔＴ）は、２５℃である。 In Comparative Example 100, the substrates 10 and 11 are in direct contact with the information recording layer 30, and the deformation layers 20 and 21 are not provided. Here, the thickness of the information recording layer 30 is 1 mm. The temperature difference (ΔT) of the optical information recording medium during recording and during reproduction is 25 ° C.
　ところで、基板１０、１１の線膨張率は、情報記録層３０に比べて１ケタ以上小さい。従って、光情報記録媒体に温度差（ΔＴ）が生じると、基板１０、１１よりも情報記録層３０のほうが膨張、収縮し易い。 By the way, the linear expansion coefficient of the substrates 10 and 11 is one digit or more smaller than that of the information recording layer 30. Therefore, when a temperature difference (ΔT) occurs in the optical information recording medium, the information recording layer 30 is more likely to expand and contract than the substrates 10 and 11.
　しかし、情報記録層３０は、基板１０、１１に直接接触しているので、情報記録層３０の面内方向は、基板１０、１１の膨張率、収縮率によって拘束される。このため、情報記録層３０の面内方向における膨張率、収縮率は、基板１０、１１とほぼ同じ程度になる。 However, since the information recording layer 30 is in direct contact with the substrates 10 and 11, the in-plane direction of the information recording layer 30 is constrained by the expansion rate and contraction rate of the substrates 10 and 11. For this reason, the expansion rate and contraction rate in the in-plane direction of the information recording layer 30 are approximately the same as those of the substrates 10 and 11.
　ところが、情報記録層３０は、温度差が生じると、基板１０、１１よりも膨張、収縮する潜在的な性質を有する。このため基板１０、１１内には内部応力が働き、基板１０、１１自体が撓んだり、縒ったりする。これに伴い、情報記録層３０の厚さ方向の膨張率、収縮率は、見かけ上、面内方向に比べ大きくなってしまう。従って、情報記録層３０の線膨張係数は異方性を持つことになり、光情報記録媒体の温度差によって情報記録層３０自体が撓んだり、縒ったりする場合がある。 However, the information recording layer 30 has a potential property of expanding and contracting more than the substrates 10 and 11 when a temperature difference occurs. For this reason, internal stress acts in the substrates 10 and 11, and the substrates 10 and 11 themselves are bent or bent. Along with this, the expansion rate and contraction rate in the thickness direction of the information recording layer 30 seem to be larger than in the in-plane direction. Therefore, the linear expansion coefficient of the information recording layer 30 has anisotropy, and the information recording layer 30 itself may be bent or wrinkled by the temperature difference of the optical information recording medium.
　これにより、比較例１００では、ページデータ（１ページ分）の中で、記録済みの干渉縞の間隔が変化し、且つ、干渉縞が傾いてしまう。　
　このため、比較例１００では、ページデータ（１ページ分）の中で、参照光の入射角、波長と干渉縞の間隔、角度が整合して再生できる場所と、これらが整合せずに再生できない場所が生じる。その結果、比較例１００では、１ページ全面を一度に再生できなくなり、再生された情報光の輝度信号が円環状になってしまう（図６（ｂ）参照）。 Thereby, in the comparative example 100, the interval of the recorded interference fringe changes in the page data (one page), and the interference fringe is inclined.
For this reason, in the comparative example 100, in the page data (for one page), the incident angle of the reference light, the interval between the wavelength and the interference fringe, the position where the angle can be reproduced, and the position cannot be reproduced without matching. A place arises. As a result, in the comparative example 100, the entire surface of one page cannot be reproduced at a time, and the luminance signal of the reproduced information light has an annular shape (see FIG. 6B).
　このような現象は、図７に示す比較例１０１にもみられる。　
　図７（ａ）には、比較例１０１に係る光情報記録媒体の構造が示され、図７（ｂ）には、このページデータの再生像が示されている。 Such a phenomenon is also observed in the comparative example 101 shown in FIG.
FIG. 7A shows the structure of an optical information recording medium according to Comparative Example 101, and FIG. 7B shows a reproduced image of this page data.
　比較例１０１では、上述した変形層２０、２１が設けられているものの、基板１０、１１の両端部の一部が情報記録層３０に接触している（矢印Ｂで示す部分）。ここで、情報記録層３０の厚みは、１ｍｍである。記録時と再生時における光情報記録媒体の温度差（ΔＴ）は、２５℃である。変形層２０、２１の厚みは、０．２ｍｍである。変形層２０、２１の材質は、東レ・ダウコーニング社製のＣＹ５２－２７６である。 In Comparative Example 101, although the above-described deformation layers 20 and 21 are provided, part of both end portions of the substrates 10 and 11 are in contact with the information recording layer 30 (part indicated by an arrow B). Here, the thickness of the information recording layer 30 is 1 mm. The temperature difference (ΔT) of the optical information recording medium during recording and during reproduction is 25 ° C. The thickness of the deformation layers 20 and 21 is 0.2 mm. The material of the deformation layers 20 and 21 is CY52-276 manufactured by Toray Dow Corning.
　このような構造でも、基板１０、１１の両端部分の一部が情報記録層３０に直接接触しているため、基板１０、１１内には、上述した内部応力が働き、基板１０、１１自体が撓んだり、縒ったりする場合がある。これにより、情報記録層３０の線膨張係数は、見かけ上、異方性を持ってしまう。その結果、比較例１０１でも、再生された情報光の輝度信号が円環状になる場合がある（図７（ｂ）参照）。 Even in such a structure, part of both end portions of the substrates 10 and 11 are in direct contact with the information recording layer 30. Therefore, the internal stress described above works in the substrates 10 and 11, and the substrates 10 and 11 themselves are It may be bent or crooked. Thereby, the linear expansion coefficient of the information recording layer 30 is apparently anisotropic. As a result, even in the comparative example 101, the reproduced luminance signal of the information light may have an annular shape (see FIG. 7B).
　これに対し、図８（図１）に示す光情報記録媒体１では、基板１０、１１と情報記録層３０との間に、変形層２０、２１が介在している。この変形層２０、２１は、情報記録層３０の主面（上面、下面）の全域に接触している。すなわち、情報記録層３０は、上方および下方から変形層２０、２１により保持されている。また、変形層２０、２１のヤング率は、情報記録層３０のヤング率の１／１０以下であり、変形層２０、２１は、情報記録層３０よりも柔らかい。 On the other hand, in the optical information recording medium 1 shown in FIG. 8 (FIG. 1), the deformable layers 20 and 21 are interposed between the substrates 10 and 11 and the information recording layer 30. The deformation layers 20 and 21 are in contact with the entire main surface (upper surface and lower surface) of the information recording layer 30. That is, the information recording layer 30 is held by the deformation layers 20 and 21 from above and below. Further, the Young's modulus of the deformation layers 20 and 21 is 1/10 or less of the Young's modulus of the information recording layer 30, and the deformation layers 20 and 21 are softer than the information recording layer 30.
　これにより、光情報記録媒体１では、温度が上昇して情報記録層３０が膨張しても、変形層２０、２１内でせん断応力が働く（変形層２０、２１内の矢印）。すなわち、基板１０、１１と情報記録層３０との線膨張率の差を変形層２０、２１が緩和する。さらに、変形層２０、２１の厚みは、変形層２０、２１の主面内において略均等に縮む。従って、情報記録層３０は、厚み方向および面内方向に等方的に膨張する（図８（ａ）参照）。特に、光情報記録媒体１においては、情報記録層３０の周囲に、空間５０が設けられている。このため、情報記録層３０が面内方向に膨張する自由度が確保されている。　
　このように、光情報記録媒体１においては、温度差が生じても、基板１０、１１が撓んだり、縒ったりし難い。その結果、情報記録層３０は、その変形が等方的になり、撓んだり、縒ったりし難い。 Thereby, in the optical information recording medium 1, even if the temperature rises and the information recording layer 30 expands, shear stress acts in the deformation layers 20 and 21 (arrows in the deformation layers 20 and 21). That is, the deformation layers 20 and 21 alleviate the difference in linear expansion coefficient between the substrates 10 and 11 and the information recording layer 30. Furthermore, the thickness of the deformation layers 20 and 21 shrinks substantially uniformly within the main surface of the deformation layers 20 and 21. Therefore, the information recording layer 30 isotropically expands in the thickness direction and the in-plane direction (see FIG. 8A). In particular, in the optical information recording medium 1, a space 50 is provided around the information recording layer 30. For this reason, the freedom degree which the information recording layer 30 expand | swells in an in-plane direction is ensured.
As described above, in the optical information recording medium 1, even if a temperature difference occurs, the substrates 10 and 11 are not easily bent or bent. As a result, the information recording layer 30 is isotropically deformed and is difficult to bend or twist.
　また、情報記録層３０の硬化収縮しても、変形層２０、２１内で、図８（ａ）とは逆の方向のせん断応力が働く（変形層２０、２１内の矢印）。さらに、変形層２０、２１の厚みは、変形層２０、２１の主面内において略均等に伸びる。従って、情報記録層３０は、厚み方向および面内方向に等方的に収縮する（図８（ｂ）参照）。すなわち、情報記録層３０の硬化収縮が生じても、光情報記録媒体１では、基板１０、１１が撓んだり、縒ったりし難い。その結果、情報記録層３０は、撓んだり、縒ったりし難い。　
　また、基板１０、１１が外部からの力により、強制的に撓んだり、縒ったりしても、変形層２０、２１の存在により、情報記録層３０は、撓んだり、縒ったりし難い。 Even if the information recording layer 30 is cured and shrunk, a shearing stress in the direction opposite to that shown in FIG. 8A acts in the deformation layers 20 and 21 (arrows in the deformation layers 20 and 21). Furthermore, the thickness of the deformation layers 20 and 21 extends substantially uniformly within the main surface of the deformation layers 20 and 21. Therefore, the information recording layer 30 isotropically contracts in the thickness direction and the in-plane direction (see FIG. 8B). That is, even when the information recording layer 30 is cured and contracted, the optical information recording medium 1 is unlikely to bend or twist the substrates 10 and 11. As a result, the information recording layer 30 is difficult to bend or curl.
In addition, even if the substrates 10 and 11 are forcibly bent or bent by an external force, the information recording layer 30 may be bent or bent due to the presence of the deformation layers 20 and 21. hard.
　これにより、光情報記録媒体１では、ページデータ（１ページ分）の中で、記録済みの干渉縞の間隔は、若干変化するものの、干渉縞の傾きについては変化し難い。その結果、ページデータ（１ページ分）の中で、参照光の入射角、波長と干渉縞の間隔、角度が整合してページデータ（１ページ分）の全てを再現することができる。再現したデータを、図８（ｃ）に示す。図示するように、再生された情報光の輝度信号は、ページデータ（１ページ分）の全域で再現されている。 Thereby, in the optical information recording medium 1, although the interval of the recorded interference fringes slightly changes in the page data (one page), the inclination of the interference fringes hardly changes. As a result, in the page data (for one page), the incident angle of the reference light, the interval between the wavelength and the interference fringe, and the angle can be matched to reproduce all of the page data (for one page). The reproduced data is shown in FIG. As shown in the figure, the luminance signal of the reproduced information light is reproduced over the entire area of the page data (for one page).
　なお、変形層２０、２１の厚さが１０μｍより小さくなると、変形層２０、２１は、その内部にせん断応力を保持し難くなる。これにより、情報記録層３０は、厚み方向および面内方向に等方的に膨張、収縮し難くなり、撓んだり、縒ったりする場合がある。　
　変形層２０、２１の厚さが５００μｍより大きくなると、変形層２０、２１の容量が大きくなり、変形層２０、２１自体が撓み易くなる。これにより、情報記録層３０は、撓んだり、縒ったりする場合がある。 When the thickness of the deformable layers 20 and 21 is smaller than 10 μm, the deformable layers 20 and 21 are difficult to hold shear stress therein. Thereby, the information recording layer 30 becomes difficult to expand and contract isotropically in the thickness direction and the in-plane direction, and may be bent or bent.
When the thickness of the deformable layers 20 and 21 is larger than 500 μm, the capacity of the deformable layers 20 and 21 is increased, and the deformable layers 20 and 21 themselves are easily bent. Thereby, the information recording layer 30 may bend or curl.
　また、変形層２０の厚みと、変形層２１の厚みとを同一にすることにより、上述したせん断応力を情報記録層３０の上方および下方で均等に分配することができる。これにより、情報記録層３０は、厚み方向および面内方向に等方的に膨張、収縮する。 Also, by making the thickness of the deformation layer 20 and the thickness of the deformation layer 21 the same, the above-described shear stress can be evenly distributed above and below the information recording layer 30. Thereby, the information recording layer 30 expands and contracts isotropically in the thickness direction and the in-plane direction.
　このように、本実施の形態の光情報記録媒体１によれば、基板１０、１１と情報記録層３０との線膨張率の差が変形層２０、２１によって緩和される。これにより、記録時と再生時の温度差、硬化収縮による再生像の劣化が抑制される。すなわち、より信頼性の高い光情報記録媒体が実現する。 As described above, according to the optical information recording medium 1 of the present embodiment, the difference in the linear expansion coefficient between the substrates 10 and 11 and the information recording layer 30 is alleviated by the deformation layers 20 and 21. Thereby, the temperature difference during recording and reproduction, and the degradation of the reproduced image due to curing shrinkage are suppressed. That is, a more reliable optical information recording medium is realized.
　さらに、光情報記録媒体１によれば、基板１０、１１の線膨張係数と情報記録層３０の線膨張係数とを近似させることを要しない。従って、基板１０、１１および情報記録層３０に関し、線膨張係数以外の他の特性（例えば、光透過率、屈折率、複屈折率、硬さ等）について選択の自由度が広がる。その結果、光情報記録媒体１に係る材料選択の自由度が大きく向上する。また、光情報記録媒体１では、温度差が生じても干渉縞が傾き難い。これにより、情報記録層３０を厚く、情報光が通過するレンズのＮＡを大きく構成しても、ページデータ全域の輝度信号を再現し易い。 Furthermore, according to the optical information recording medium 1, it is not necessary to approximate the linear expansion coefficient of the substrates 10 and 11 and the linear expansion coefficient of the information recording layer 30. Accordingly, with respect to the substrates 10 and 11 and the information recording layer 30, the degree of freedom in selecting other characteristics (for example, light transmittance, refractive index, birefringence, hardness, etc.) other than the linear expansion coefficient is expanded. As a result, the degree of freedom of material selection related to the optical information recording medium 1 is greatly improved. Further, in the optical information recording medium 1, the interference fringes are difficult to tilt even if a temperature difference occurs. Thereby, even if the information recording layer 30 is thick and the NA of the lens through which the information light passes is configured to be large, it is easy to reproduce the luminance signal of the entire page data.
　次に、光情報記録媒体の変形例について説明する。　
　なお、以下の説明する変形例では、光情報記録媒体１と同一の部材には同一の符号を付し、その詳細な説明については適宜省略する。 Next, a modification of the optical information recording medium will be described.
In the modification described below, the same members as those of the optical information recording medium 1 are denoted by the same reference numerals, and detailed description thereof will be omitted as appropriate.
　図９は、光情報記録媒体の要部模式図である。図９（ａ）には、光情報記録媒体２の要部上面が示され、図９（ｂ）（ｃ）には、図９（ａ）のＸ－Ｙ断面が示されている。　
　上述した光情報記録媒体１の内部には、空間５０が設けられているが、光情報記録媒体２の内部には、このような空間が設けられていない。但し、スペーサ４０の線膨張係数は、基板１０、１１の線膨張係数よりも大きい。スペーサ４０の材質は、例えば、テフロン（登録商標）等のフッ化炭素樹脂である。 FIG. 9 is a schematic diagram of a main part of an optical information recording medium. 9A shows the top surface of the main part of the optical information recording medium 2, and FIGS. 9B and 9C show the XY cross section of FIG. 9A.
A space 50 is provided in the optical information recording medium 1 described above, but such a space is not provided in the optical information recording medium 2. However, the linear expansion coefficient of the spacer 40 is larger than the linear expansion coefficient of the substrates 10 and 11. The material of the spacer 40 is, for example, a fluorocarbon resin such as Teflon (registered trademark).
　このような構造であれば、光情報記録媒体２の温度上昇とともに、スペーサ４０自体が光情報記録媒体２の外方に拡がって、スペーサ４０と情報記録層３０と間に若干の間隙（空間５０）が形成する場合がある（図９（ｃ）参照）。 With such a structure, as the temperature of the optical information recording medium 2 rises, the spacer 40 itself spreads outward from the optical information recording medium 2, and a slight gap (space 50) is formed between the spacer 40 and the information recording layer 30. ) May be formed (see FIG. 9C).
　このように、光情報記録媒体２においても、情報記録層３０が面内方向に膨張する自由度が確保されている。すなわち、光情報記録媒体２に温度差が生じても、基板１０、１１が撓んだり、縒ったりし難い。その結果、情報記録層３０は、撓んだり、縒ったりし難い。　
　このような光情報記録媒体２においても、光情報記録媒体１と同様の効果が得られる。 Thus, also in the optical information recording medium 2, the degree of freedom that the information recording layer 30 expands in the in-plane direction is ensured. That is, even if a temperature difference occurs in the optical information recording medium 2, the substrates 10 and 11 are not easily bent or bent. As a result, the information recording layer 30 is difficult to bend or curl.
Also in such an optical information recording medium 2, the same effect as the optical information recording medium 1 can be obtained.
　図１０は、光情報記録媒体の要部模式図である。図１０（ａ）には、光情報記録媒体３の要部上面が示され、図１０（ｂ）には、図１０（ａ）のＸ－Ｙ断面が示されている。　
　光情報記録媒体３においては、スペーサ４０が基板１０、１１と同じ材により構成されている。さらに、スペーサ４０は、基板１０および基板１０の少なくともいずれかと一体的に構成されている。図１０（ｂ）には、一例として、基板１１とスペーサ４０とが一体となった構造が示されている。 FIG. 10 is a schematic diagram of a main part of an optical information recording medium. FIG. 10A shows the top surface of the main part of the optical information recording medium 3, and FIG. 10B shows the XY cross section of FIG. 10A.
In the optical information recording medium 3, the spacer 40 is made of the same material as the substrates 10 and 11. Further, the spacer 40 is configured integrally with at least one of the substrate 10 and the substrate 10. FIG. 10B shows a structure in which the substrate 11 and the spacer 40 are integrated as an example.
　このような光情報記録媒体３においても、光情報記録媒体１と同様の効果が得られる。特に、基板１１とスペーサ４０とを一体的に製造できるので、より低コストで光情報記録媒体を製造できる。 Even in such an optical information recording medium 3, the same effect as the optical information recording medium 1 can be obtained. In particular, since the substrate 11 and the spacer 40 can be manufactured integrally, an optical information recording medium can be manufactured at a lower cost.
　図１１は、光情報記録媒体の要部模式図である。図１１（ａ）には、光情報記録媒体４の要部上面が示され、図１１（ｂ）には、図１１（ａ）のＸ－Ｙ断面が示されている。　
　光情報記録媒体４においては、変形層２０、２１内に、変形層２０、２１の厚さと略同じ径の球状の支持部材６０が配置されている。支持部材６０は、図１１（ａ）に示すように格子状に配置してもよく、ハニカム状に配置してもよい。支持部材６０の屈折率、透過率は、変形層２０、２１の屈折率、透過率と略同一あるいは近似させることが好ましい。これにより、変形層２０、２１および支持部材６０を含む層は、見かけ上、光学的に均質な層になる。支持部材６０の材質としては、ガラス、有機樹脂などが挙げられる。 FIG. 11 is a schematic diagram of a main part of an optical information recording medium. FIG. 11A shows the top surface of the main part of the optical information recording medium 4, and FIG. 11B shows the XY cross section of FIG. 11A.
In the optical information recording medium 4, a spherical support member 60 having a diameter substantially the same as the thickness of the deformation layers 20, 21 is disposed in the deformation layers 20, 21. The support member 60 may be arranged in a lattice shape as shown in FIG. 11A, or may be arranged in a honeycomb shape. The refractive index and transmittance of the support member 60 are preferably substantially the same as or similar to the refractive index and transmittance of the deformable layers 20 and 21. Thereby, the layer including the deformable layers 20 and 21 and the support member 60 is apparently optically homogeneous. Examples of the material of the support member 60 include glass and organic resin.
　このような支持部材６０を変形層２０、２１内に配置することにより、情報記録層３０は、変形層２０、２１のほか、支持部材６０によっても上方および下方から支持される。すなわち、光情報記録媒体４に係る情報記録層３０は、光情報記録媒体１の情報記録層３０よりも、より撓み難くなり、縒り難くなる。この場合、支持部材６０と情報記録層３０とが接する部分以外の情報記録層３０は、等方的に膨張し、収縮することができる。 By arranging such a support member 60 in the deformable layers 20 and 21, the information recording layer 30 is supported from above and below by the support member 60 in addition to the deformable layers 20 and 21. That is, the information recording layer 30 according to the optical information recording medium 4 is more difficult to bend and more difficult to bend than the information recording layer 30 of the optical information recording medium 1. In this case, the information recording layer 30 other than the portion where the support member 60 and the information recording layer 30 are in contact can expand and contract isotropically.
　これにより、光情報記録媒体４では、光情報記録媒体１よりも、より安定してページデータを再現することができる。　
　なお、支持部材６０の形状は、上述した球状以外のほか、立方体状、円柱状、円筒状、円錐状、かまぼこ型状などであってもよい。また、支持部材６０と基板１０、１１とは、一体的に形成してもよい。また、支持部材６０が配置された部分を中空としてもよい。 Thereby, the optical information recording medium 4 can reproduce the page data more stably than the optical information recording medium 1.
In addition to the spherical shape described above, the shape of the support member 60 may be a cubic shape, a columnar shape, a cylindrical shape, a conical shape, a kamaboko shape, or the like. Further, the support member 60 and the substrates 10 and 11 may be integrally formed. Further, the portion where the support member 60 is disposed may be hollow.
　図１２は、光情報記録媒体の要部模式図である。図１２（ａ）には、光情報記録媒体５の要部上面が示され、図１２（ｂ）には、図１２（ａ）のＸ－Ｙ断面が示されている。　
　光情報記録媒体５においては、その主面の形状が円板型であり、中心に中心軸７０が設けられている。中心軸７０の周りには、スペーサ７１が設けられている。光情報記録媒体５は、中心軸７０を中心に回転する。　
　このような構造であれば、光情報記録媒体５を所謂ディスク型の記録媒体として用いることができる。 FIG. 12 is a schematic diagram of a main part of an optical information recording medium. FIG. 12A shows the top surface of the main part of the optical information recording medium 5, and FIG. 12B shows the XY cross section of FIG. 12A.
In the optical information recording medium 5, the shape of the main surface is a disk shape, and a central axis 70 is provided at the center. A spacer 71 is provided around the central axis 70. The optical information recording medium 5 rotates around the central axis 70.
With such a structure, the optical information recording medium 5 can be used as a so-called disk type recording medium.
　図１３は、光情報記録媒体の要部模式図である。図１３（ａ）には、光情報記録媒体６の要部上面が示され、図１３（ｂ）には、図１３（ａ）のＸ－Ｙ断面が示されている。 FIG. 13 is a schematic diagram of a main part of an optical information recording medium. FIG. 13 (a) shows the top surface of the main part of the optical information recording medium 6, and FIG. 13 (b) shows the XY cross section of FIG. 13 (a).
　光情報記録媒体６においては、情報記録層３０の外周のほか、情報記録層３０内に空間５０が設けられている。換言すれば、情報記録層３０は、空間５０を隔てて、個々の情報記録層３０ａに分割されている。 In the optical information recording medium 6, a space 50 is provided in the information recording layer 30 in addition to the outer periphery of the information recording layer 30. In other words, the information recording layer 30 is divided into individual information recording layers 30 a with a space 50 therebetween.
　このような構造であれば、個々の情報記録層３０ａが面内方向に膨張、収縮する自由度は、さらに向上する。これにより、情報記録層３０が等方的に膨張、収縮する自由度はより向上する。その結果、光情報記録媒体６は、光情報記録媒体１よりも、より安定してページデータを再現することができる。なお、情報記録層３０内の空間５０の位置は、図１３に示す位置に限らない。例えば、光情報記録媒体６の中心部に設けてもよい。また、個々の情報記録層３０ａの主面の形状は、矩形状である必要はなく、円形状、四角以外の多角形状としてもよい。 With such a structure, the degree of freedom with which each information recording layer 30a expands and contracts in the in-plane direction is further improved. Thereby, the degree of freedom that the information recording layer 30 expands and contracts isotropically is further improved. As a result, the optical information recording medium 6 can reproduce the page data more stably than the optical information recording medium 1. The position of the space 50 in the information recording layer 30 is not limited to the position shown in FIG. For example, it may be provided at the center of the optical information recording medium 6. In addition, the shape of the main surface of each information recording layer 30a is not necessarily rectangular, and may be a circular shape or a polygonal shape other than a square shape.
　以上、具体例を参照しつつ本発明の実施の形態について説明した。しかし、本発明はこれらの実施の形態に限定されるものではない。すなわち、これら具体例に、当業者が適宜設計変更を加えたものも、本発明の特徴を備えている限り、本発明の範囲に包含される。例えば、前述した各具体例が備える各要素およびその配置、材料、条件、形状、サイズなどは、例示したものに限定されるわけではなく適宜変更することができる。 The embodiments of the present invention have been described above with reference to specific examples. However, the present invention is not limited to these embodiments. In other words, those specific examples that have been appropriately modified by those skilled in the art are also included in the scope of the present invention as long as they have the characteristics of the present invention. For example, the elements included in each of the specific examples described above and their arrangement, materials, conditions, shapes, sizes, and the like are not limited to those illustrated, but can be changed as appropriate.
　なお、変形層２０、２１が変形層２０、２１の主面に略平行な方向に変形しつつ、その厚みを変形層２０、２１の主面内において略均等に変えることにより、情報記録層３０の厚み方向および主面内方向に等方的に膨張もしくは収縮するためには、変形層２０および変形層２１の上述した物性値、材料、膜厚、形状等は、一致させることが望ましい。但し、画像の再生劣化が許容される範囲内であれば、これらを一致させない形態も本実施の形態に含まれる。 The information recording layer 30 is obtained by changing the thickness of the deformable layers 20 and 21 in a direction substantially parallel to the main surfaces of the deformable layers 20 and 21 and changing the thickness thereof substantially uniformly in the main surfaces of the deformable layers 20 and 21. In order to expand or contract isotropically in the thickness direction and the in-plane direction, it is desirable that the above-described physical property values, materials, film thicknesses, shapes, and the like of the deformable layer 20 and the deformable layer 21 match. However, a form in which these are not matched is also included in the present embodiment as long as the reproduction degradation of the image is allowable.
　また、前述した各実施の形態が備える各要素は、技術的に可能な限りにおいて複合させることができ、これらを組み合わせたものも本発明の特徴を含む限り本発明の範囲に包含される。　
　その他、本発明の思想の範疇において、当業者であれば、各種の変更例および修正例に想到し得るものであり、それら変更例および修正例についても本発明の範囲に属するものと了解される。 In addition, each element included in each of the above-described embodiments can be combined as long as technically possible, and combinations thereof are also included in the scope of the present invention as long as they include the features of the present invention.
In addition, in the category of the idea of the present invention, those skilled in the art can conceive of various changes and modifications, and it is understood that these changes and modifications also belong to the scope of the present invention. .
　本発明によれば、材料選択の自由度が損なわず、より信頼性の高い光情報記録媒体が提供される。 According to the present invention, a more reliable optical information recording medium is provided without deteriorating the degree of freedom of material selection.
　１、２、３、４、５、６　光情報記録媒体　
　１０、１１　基板　
　１０ｔ、１１ｔ　両端部　
　２０、２１　変形層　
　３０、３０ａ　情報記録層　
　３１　情報光　
　３２　参照光　
　４０　スペーサ　
　５０　空間　
　６０　支持部材　
　７０　中心軸　
　７１　スペーサ　
　１００、１０１　比較例　
　Ｂ　矢印　
　Ｅｒ、Ｅｔ　ヤング率　
　Ｔｔ 厚さ　 1, 2, 3, 4, 5, 6 Optical information recording medium
10, 11 substrate
10t, 11t both ends
20, 21 deformation layer
30, 30a Information recording layer
31 Information light
32 Reference light
40 Spacer
50 spaces
60 Support members
70 Center axis
71 Spacer
100, 101 comparative example
B Arrow
Er, Et Young's modulus
Tt thickness

Claims (8)

  1. 　情報をホログラムとして記録再生する光情報記録媒体であって、
    　第１の基板と、
    　前記第１の基板に対向する第２の基板と、
    　前記第１の基板と前記第２の基板との間に挟まれた情報記録層と、
    　前記第１の基板と前記情報記録層との間に設けられた第１の変形層と、
    　前記第２の基板と前記情報記録層との間に設けられた第２の変形層と、
    　を備えたことを特徴とする光情報記録媒体。     An optical information recording medium for recording and reproducing information as a hologram,
    A first substrate;
    A second substrate facing the first substrate;
    An information recording layer sandwiched between the first substrate and the second substrate;
    A first deformation layer provided between the first substrate and the information recording layer;
    A second deformation layer provided between the second substrate and the information recording layer;
    An optical information recording medium comprising:
  2. 　前記第１の変形層および前記第２の変形層の少なくともいずれかは、シリコーン樹脂、合成ゴム、アクリロニトリル－塩素化ポリエチレン－スチレン共重合体樹脂、液晶ポリマ、熱可塑性エラストマ、エポキシ樹脂のいずれかからなることを特徴とする請求項１記載の光情報記録媒体。 At least one of the first deformation layer and the second deformation layer is made of any of silicone resin, synthetic rubber, acrylonitrile-chlorinated polyethylene-styrene copolymer resin, liquid crystal polymer, thermoplastic elastomer, and epoxy resin. The optical information recording medium according to claim 1, wherein
  3. 　前記第１の変形層および前記第２の変形層の少なくともいずれかのヤング率は、前記情報記録層のヤング率の１０分の１以下であることを特徴とする請求項１記載の光情報記録媒体。 2. The optical information recording according to claim 1, wherein a Young's modulus of at least one of the first deformation layer and the second deformation layer is 1/10 or less of a Young's modulus of the information recording layer. Medium.
  4. 　前記第１の変形層および前記第２の変形層の少なくともいずれかのヤング率をＥｔ、厚さをＴｔ、前記情報記録層のヤング率をＥｒ、としたときに、
    　（Ｅｒ／Ｅｔ）×Ｔｔ≧１０（ｍｍ）
    　であることを特徴とする請求項１記載の光情報記録媒体。     When the Young's modulus of at least one of the first deformable layer and the second deformable layer is Et, the thickness is Tt, and the Young's modulus of the information recording layer is Er,
    (Er / Et) × Tt ≧ 10 (mm)
    The optical information recording medium according to claim 1, wherein:
  5. 　前記第１の変形層および前記第２の変形層の少なくともいずれかの厚さは、１０ミクロン以上５００ミクロン以下であることを特徴とする請求項１記載の光情報記録媒体。 2. The optical information recording medium according to claim 1, wherein the thickness of at least one of the first deformable layer and the second deformable layer is not less than 10 microns and not more than 500 microns.
  6. 　前記第１の変形層および前記第２の変形層の少なくともいずれかは、前記情報記録層を支持する支持部材を含むことを特徴とする請求項１記載の光情報記録媒体。 2. The optical information recording medium according to claim 1, wherein at least one of the first deformation layer and the second deformation layer includes a support member that supports the information recording layer.
  7. 　前記情報記録層の周囲もしくは前記情報記録層内において前記第１の基板と前記第２の基板との間に空間が設けられていることを特徴とする請求項１記載の光情報記録媒体。 2. The optical information recording medium according to claim 1, wherein a space is provided between the first substrate and the second substrate around the information recording layer or in the information recording layer.
  8. 　前記情報記録層は、温度の変化に応じて前記第１の変形層および前記第２の変形層が変形することにより、等方的に膨張もしくは収縮することを特徴とする請求項１記載の光情報記録媒体。 2. The light according to claim 1, wherein the information recording layer expands or contracts isotropically when the first deformable layer and the second deformable layer are deformed according to a change in temperature. Information recording medium.
PCT/JP2009/065594 2009-09-07 2009-09-07 Optical information recording medium WO2011027472A1 (en)

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Citations (6)

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JPH03220503A (en) * 1990-01-26 1991-09-27 Fujitsu Ltd Method for adhering hologram optical element
JPH08137373A (en) * 1994-11-07 1996-05-31 Dainippon Printing Co Ltd Multilayered hologram recording material
JPH08286589A (en) * 1995-04-12 1996-11-01 Dainippon Printing Co Ltd Multilayered hologram recording material
JP2002032001A (en) * 2000-06-08 2002-01-31 Lucent Technol Inc Holographic memory medium and method for manufacturing the same as well as holographic memory device
JP2005321597A (en) * 2004-05-10 2005-11-17 Tdk Corp Holographic recording medium, its recording method, and its recording and reproducing device
JP2008152041A (en) * 2006-12-18 2008-07-03 Toshiba Corp Hologram-recording medium and its manufacturing method

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH03220503A (en) * 1990-01-26 1991-09-27 Fujitsu Ltd Method for adhering hologram optical element
JPH08137373A (en) * 1994-11-07 1996-05-31 Dainippon Printing Co Ltd Multilayered hologram recording material
JPH08286589A (en) * 1995-04-12 1996-11-01 Dainippon Printing Co Ltd Multilayered hologram recording material
JP2002032001A (en) * 2000-06-08 2002-01-31 Lucent Technol Inc Holographic memory medium and method for manufacturing the same as well as holographic memory device
JP2005321597A (en) * 2004-05-10 2005-11-17 Tdk Corp Holographic recording medium, its recording method, and its recording and reproducing device
JP2008152041A (en) * 2006-12-18 2008-07-03 Toshiba Corp Hologram-recording medium and its manufacturing method

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