JP2005283618A - Optical recording medium and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical recording medium which has excellent recording characteristics and has optical information recording layers having the excellent recording characteristics and having a relatively large thickness, and its manufacturing method. <P>SOLUTION: The optical recording medium has a substrate and the optical information recording layers, wherein the optical information recording layers are composed of a plurality of layers alternately formed in order of optical recording layers and a transparent support layer of 10 to 200 μm in thickness, successively from the substrate side, and its manufacturing method is provided. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an optical recording medium and a manufacturing method thereof, and more particularly to an optical recording medium having a relatively thick optical information recording layer and a manufacturing method thereof used for three-dimensional optical recording such as a multilayer optical memory and a hologram memory.

  In optical recording media such as multilayer optical memories and holographic memories, information is recorded not only in the in-plane direction of the medium but also in the depth direction. That is, by recording a signal three-dimensionally using the surface of the information recording area provided on the medium and the depth direction of the information recording area (the thickness direction of the medium), high density and large capacity Information recording becomes possible. For example, in holographic memory, a volume multiplex recording type holographic optical recording medium has been developed that enables large-capacity information recording by three-dimensionally writing interference fringes using the thickness direction of the recording medium. Yes. There is also an optical recording medium that can record a large volume of three-dimensional information by recording a signal in the depth direction using a non-resonant absorption process in which molecules absorb two photons simultaneously and are excited. Are known.

  However, in the production of these optical recording media, it is difficult to form a uniform and relatively thick optical information recording layer. Conventionally, a thin layer of less than 10 μm is uniformly formed by a spin coating method that has been widely used as a method for forming an information recording layer on a disc-shaped recording medium. However, it is difficult to uniformly form a thick information recording layer of 100 μm or more by spin coating. For example, if the substrate is rotated at a low speed in order to apply a thick optical recording material to the surface of the substrate, the coating film made of the optical recording material formed on the substrate will have a thick edge portion and a uniform thickness. It is difficult to form the information recording layer. A method of adjusting the viscosity of the coating solution containing the optical recording material is also conceivable, but it is often difficult in view of the influence on the characteristics of the medium.

  There is also a method of creating a medium by applying a recording material to a relatively thick support and then punching it into a disk shape, as in the case of making a flexible disk. However, with this method, it is difficult to apply the recording material to a thickness of 100 μm or more on the support even if the application speed is slow.

  Therefore, in order to create an optical recording medium having a relatively thick information recording layer, Patent Document 1 discloses a space formed by bonding two transparent substrates together via a spacer. A method for forming an information recording layer by injecting a photocurable or thermosetting resin as an optical recording material and curing it has been proposed. However, in this method, in order to form an information recording layer, a photocurable or thermosetting resin is dissolved in a solvent and injected into a space between the two transparent substrates, and then between the two transparent substrates. It is difficult to remove the solvent from Moreover, when the viscosity of the photocurable or thermosetting resin material injected into the space between the two transparent substrates is high, it is expected that the injection of the resin material is difficult. It is difficult to make the intervals between the transparent substrates uniform and costly, which is not realistic.

  Further, Non-Patent Document 1 proposes a recording medium in which recording layers and non-recording layers are alternately stacked. However, in this recording medium, both the recording layer and the non-recording layer are as thin as 10 μm or less, and in order to obtain a thick recording layer, many layers must be laminated, and each layer has a uniform thickness. There is a problem that it is technically difficult to obtain a thickness of 100 μm or more by stacking.

Patent Document 2 proposes an optical recording medium in which two or more optical recording layers made of a photosensitive material are stacked via a non-recording layer made of a light transmissive material. In this optical recording medium, a light-transmitting material is spin-coated on a substrate to form a recording layer, and then a support made of the light-transmitting material is thermocompression-bonded on the recording layer to form a non-recording layer. Further, it is manufactured by sequentially forming a recording layer by spin coating on the non-recording layer and forming a non-recording layer by thermocompression bonding. However, since the process of thermocompression bonding the support is repeated many times after forming the recording layer, it is costly, and in the thermocompression bonding process, each non-recording layer is displaced, and the recording layer is laminated. There is a problem that the edge of the non-recording layer shifts and the edge shift adversely affects the formation of the recording layer by spin coating.
Japanese Patent Laying-Open No. 2001-005368 (Claim 1, Claim 2, FIG. 1) JP 2000-105529 A (Claim 1, paragraph [0030], FIG. 3) Yoshimasa Kawada, Optronics, No.11, 138-142,2001

  SUMMARY OF THE INVENTION An object of the present invention is to provide an optical recording medium having excellent recording characteristics and a relatively thick optical information recording layer, and a method for producing the same.

  In order to solve the above problems, an optical recording medium of the present invention has a substrate and an optical information recording layer bonded onto the substrate, and the optical information recording layer is an optical recording layer from the substrate side, It is characterized by comprising a plurality of layers alternately formed in the order of transparent support layers having a thickness of 10 to 200 μm.

  In this optical recording medium, the optical information recording layer having two or more optical recording layers has excellent recording characteristics and a large capacity recording density because the total thickness of the optical recording layers is relatively thick. Become.

  The method for producing the optical recording medium of the present invention comprises the steps of applying an optical recording material on one side of a 10-200 μm transparent support to form an optical recording layer to obtain an optical recording, and said transparent support Forming the optical information recording body by stacking a plurality of optical recording bodies, and forming the optical information recording body into a predetermined shape so that the optical information recording layers are alternately arranged. And a step of bonding the molded optical information recording body to the substrate so that the optical recording layer is in contact with the substrate.

  In this method, an optical recording medium having an optical information recording layer having a total thickness of 150 μm or more between the transparent support and the substrate can be produced by laminating the plurality of optical recording layers.

  In the present invention, the “optical recording medium” refers to a recording medium capable of recording an information signal on an optical information recording layer by light and reading the recorded information signal. For example, it refers to a recording medium capable of recording optical information by physical and chemical mechanisms such as holography and two-photon absorption, and reading the recorded information.

  In the optical recording medium of the present invention, since the optical information recording layer is formed by laminating a plurality of optical recording layers that are relatively thin and have few bubbles, the optical information recording layer is excellent in optical recording characteristics and relatively thick. Therefore, three-dimensional optical recording with high recording density and large capacity is possible. In a multilayer optical memory using two-photon absorption, recording capacity increases because optical recording can be performed on each optical recording layer divided by the support layer. In a holographic memory, the thicker the medium, the smaller the shift amount and the greater the multiplicity, thus increasing the recording capacity.

  Also, according to the manufacturing method of the present invention, it is possible to easily and inexpensively produce an optical recording medium having a relatively thick optical recording layer in total as the optical information recording layer. In addition, the film thickness of the optical recording layer can be made uniform, and compared with a conventional manufacturing method in which a film is thermocompression bonded for each layer, the edge shift for each layer is small, and has excellent optical recording characteristics. An optical recording medium capable of three-dimensional optical recording with high recording density and large capacity can be manufactured.

FIG. 1 is a schematic cross-sectional view showing a laminated structure of an optical recording medium OM according to an embodiment of the present invention.
An optical recording medium OM shown in FIG. 1 has a substrate 1 and an optical information recording layer 2 laminated on the substrate 1. The optical information recording layer 2 includes a first optical recording layer 2a, a first support layer 3a, a second optical recording layer 2b, a second support layer 3b, a third optical recording layer 2c, and a third support layer 3c in this order. Have a laminated structure.

  The board | substrate 1 is not specifically limited, It is comprised with the film or sheet | seat which consists of a natural or synthetic organic synthetic resin. Examples thereof include inorganic substances such as glass, organic synthetic resins such as polycarbonate, polyethylene terephthalate, triacetyl cellulose, acrylic resin, methacrylic resin, polystyrene resin, vinyl chloride resin, epoxy resin, polyester resin, and amorphous polyolefin. Among these, when the optical recording medium of the present invention is applied to both a two-photon absorption memory and a holographic memory, a material having low birefringence is preferable, and specifically, glass or polycarbonate is preferable.

  The substrate 1 may be provided with a reflective layer on the surface 1a in contact with the optical information recording layer 2, and the reflective layer is composed solely of elemental components such as Au, Ag, Al, Pt, Cu, Ni, Si, Ge, and Cr. Alternatively, it is preferably formed using a material sputtered in a state containing other elements.

Further, the substrate 1 is preferably relatively thick, for example, preferably about 300 to 1500 μm.
Further, on the surface 1a in contact with the optical information recording layer 2 of the substrate 1, information for performing servo control such as tracking servo and focus servo, and information for identifying the address of the information recording area, etc. are provided. A servo signal recording area including patterns and pits may be formed in advance. Thereby, in the hologram memory, interference fringes are formed accurately by the interference of the reference light and the information light in the optical information recording layer, and the optical information can be recorded accurately. Also in the reproduction, the optical information can be accurately reproduced by the reference light.

As shown in FIG. 1, the optical information recording layer 2 includes a first optical recording layer 2a, a second optical recording layer 2b, and a third optical recording layer 2c made of an optical recording material.
Each of the optical recording layers 2a, 2b, and 2c has optical characteristics such as a refractive index, a dielectric constant, a reflectance, and an absorptance according to the intensity of the laser beam when irradiated with a laser beam (reference light, information light). Formed by changing optical recording material.

  As the optical recording material, in the case of a medium for optical recording by two-photon absorption, it consists only of a compound that itself causes some chemical or physical change by performing two-photon or multi-photon absorption. A photon or multiphoton absorbing compound and a second compound in which some chemical or physical change is induced by the two-photon or multiphoton absorption, or a two-photon or multiphoton absorbing compound and the two-photon of the compound Alternatively, in addition to the second compound that is induced by multiphoton absorption to cause a chemical or physical change, a compound containing a third compound that plays a role in adjusting the recording mechanism can be used. Examples of the optical recording material include those described in JP-A No. 2002-172864.

  In addition, in the case of a medium for optical recording due to holograms, a material whose physical properties change along the brightness of interference fringes formed in the recording material, such as a difference in refractive index or transmittance Can be used.

  Specific examples of the optical recording material for hologram include silver halide, dichromated gelatin, photorefractive material, photochromic material, and photopolymer material. Among these, photopolymer materials have become the mainstream of research because of high diffraction efficiency, low noise, and good storage stability if they are completely fixed after recording. This photopolymer material usually contains a binder, a monomer, a sensitizing dye, a polymerization initiator, and the like. It is desirable to use binders and monomers having different refractive indexes. At the time of recording optical information, if an interference fringe is formed in the optical recording medium, the sensitizing dye is excited and emits electrons in the bright part of the interference fringe. The emitted electrons move to the polymerization initiator to generate radicals, and the radicals move to the monomers to start polymerization. Some monomers cause polymerization with an acid generator. As a result, the interference fringe bright portion is monomer-rich and the interference fringe dark portion is binder-rich, and the refractive index difference is recorded as an interference fringe in the optical recording medium. Monomers that are not used for recording optical information are exposed and fixed using a laser or a white light source after recording. Also, depending on the material, it may be fixed by heat treatment.

  In addition to the above substances, any material can be used as the hologram recording material as long as the physical properties of the material change along the light and darkness of the interference fringes and a difference in refractive index or transmittance occurs. For example, those that cause a change in refractive index due to coloring or decoloring of the dye can be used. Further, combinations thereof, for example, a composition containing a dye that develops or decolors upon irradiation with light and a photopolymer, a composition containing a photorefractive material and a photopolymer, and the like can also be used as the hologram recording material.

  This optical recording material is commonly used for forming an optical information recording layer of this type of optical recording medium such as a binder, a photopolymerization initiator, a sensitizer, an optical brightener, an ultraviolet absorber, and a heat stabilizer. Things may be included as needed.

The total thickness of the optical recording layers 2a, 2b, 2c in the optical information recording layer 2 is 150 μm or more, preferably 500 μm or more. If it is less than 150 μm, it becomes difficult to perform three-dimensional optical recording with a high recording density and a large recording capacity, such as a hologram memory or a two-photon absorption memory.
Further, the thicknesses of the first optical recording layer 2a, the second optical recording layer 2b, and the third optical recording layer 2c constituting the optical information recording layer 2 are not particularly limited, and may be the same or different. In particular, when the medium has a large recording capacity (500 GB or more), the total thickness (2a + 2b + 2c) of the optical recording layer is preferably 500 μm or more.

  The first support layer 3a, the second support layer 3b, and the third support layer 3c are laminated on the first optical recording layer 2a, the second optical recording layer 2b, and the third optical recording layer 2c, respectively. As described above, when the optical information recording layer 2 is formed, the optical information recording layer 2 serves as a support for the first optical recording layer 2a, the second optical recording layer 2b, and the third optical recording layer 2c, and is incident from the outside of the support layer 3. The third support layer 3c on the outer side has a role of a protective layer. The first support layer 3a, the second support layer 3b, and the third support layer 3c are preferably formed of polycarbonate, triacetyl cellulose, polymethacrylate, or the like having low birefringence.

  Each of the first support layer 3a, the second support layer 3b, and the third support layer 3c has a thickness of 10 to 200 μm, preferably 30 to 100 μm. When the thickness of each support layer is less than 10 μm, it is difficult to apply the optical recording layer by uniformly controlling the thickness of the optical recording layer because the support layer is thin. When the thickness exceeds 200 μm, the obtained optical recording medium is predetermined. There is a risk that distortion may occur when the medium is cut or punched in the process of forming the shape.

  In the optical recording medium OM of the present invention, the substrate 1 and the optical information recording layer 2 are bonded together by thermocompression bonding, an adhesive layer interposed between the two layers, or the optical information recording layer 2. Among these, any mode in which the optical recording layer 2a in contact with the substrate contains an adhesive component and is bonded to the substrate 1 by this adhesive component may be employed. As the adhesive layer or adhesive component, for example, a thermoplastic adhesive mainly composed of vinyl acetate, acrylic ester, vinyl chloride, acrylic acid, polyamide, polyester, polyurethane, etc., or a phenol-based or urea-based thermosetting adhesive Agents, epoxy-based, and isocyanate-based curing agent-curable adhesives can be used.

  In the above embodiment, the optical recording medium OM having the optical information recording layer 2 including the three optical recording layers 2a, 2b, and 2c has been described. However, in the optical recording medium of the present invention, the optical information recording layer Is not limited to the structure composed of the three optical recording layers 2a, 2b, and 2c shown in FIG. 1, and any optical recording medium can be used as long as it is composed of two or more optical recording layers. The number of layers is appropriately determined according to the optical information recording method.

  The production of the optical recording medium of the present invention is a method capable of producing an optical recording medium having an optical information recording layer constituted by alternately laminating a plurality of optical recording layers and a support layer on a substrate. If there is, it does not restrict | limit in particular, You may follow according to any method. In this method, an optical recording material is formed on one surface of a transparent support to form an optical recording layer to obtain an optical recording body, and the transparent support and the optical information recording layer are alternately arranged. A step of laminating a plurality of the optical recording bodies to form an optical information recording body having a total thickness of 150 μm or more, and a step of forming the optical information recording body into a predetermined shape And a step of bonding the molded optical information recording body to the substrate so that the optical recording layer is in contact with the substrate, making an optical recording medium having a relatively thick optical information recording layer easy and low This is advantageous in that it is possible at a low cost and the thickness of the optical recording layer can be made uniform.

  For this method, the three layers of the first optical recording layer 2a, the second optical recording layer 2b, and the third optical recording layer 2c shown in FIG. 1, the first support layer 3a, the second support layer 3b, and the third support are shown. A method for manufacturing an optical recording medium OM having the optical information recording layer 2 composed of the body layer 3c will be described as an example with reference to FIGS. 2 (a) to 2 (c).

  First, as shown in FIG. 2A, a coating liquid containing an optical recording material is applied to a predetermined thickness on a transparent support 4 having a thickness of 10 to 200 μm, and then optical recording in the coating film is performed. The optical recording layer 5 is formed by drying until the content of the solvent component not involved in the content is 10% by mass or less. In this way, three optical recording bodies 6 in which the optical recording layer 5 is laminated on the transparent support 4 are manufactured.

  The coating liquid containing the optical recording material is composed of the above-mentioned photocurable or thermosetting resin constituent monomers, and a binder, photopolymerization initiator, sensitizer, optical enhancer, which are blended as necessary. It can prepare by mixing each component, such as a white agent, a ultraviolet absorber, and a heat stabilizer, adding a solvent and stirring. The coating solution is preferably prepared under illumination in a dark room such as a red lamp in order to prevent the optical recording material from curing.

  Moreover, although the viscosity of a coating liquid is suitably adjusted with the coating method to be used, it is about 0.1-50 Ps normally. In particular, when applying using a coater knife such as a doctor knife, the viscosity is preferably about 1 to 30 Ps.

  The coating method of the coating liquid onto the transparent support 4 can be performed using a dip coating method, a coater, a rod, a coil bar, a Giesser, a blade device, or the like. In particular, in order to obtain a uniform and thick optical recording layer, a coating method using a coil bar or a rod is preferable.

  Next, the obtained three optical recording bodies 6 are laminated from the bottom to the transparent support 4 and the optical recording layer 5 in this order, and the first optical recording is performed from the top as shown in FIG. The optical information recording body 7 in which the layer 5a, the first support 4a, the second optical recording layer 5b, the second support 4b, the third optical recording layer 5c, and the third support 4c are laminated in this order is manufactured.

  Further, as shown in FIG. 2C, the optical information recording body 7 is formed into a predetermined shape by a method such as punching or cutting. The optical information recording body 7 is formed into a predetermined shape such as a disk shape or a card shape according to the use of a security medium such as an optical recording medium or an ID card.

Finally, the molded optical information recording body 7 is bonded to the substrate 1 such that the first optical recording layer 5a is interposed between the first support 4a and the substrate 1.
The optical information recording body 7 and the substrate 1 can be bonded by thermocompression bonding, bonding an adhesive layer under the first optical recording layer 5a of the optical information recording body 7, An adhesive component may be added in advance to the first optical recording layer 5 a in contact with the substrate 1 in the information recording body 7, and adhesion may be performed using this adhesive component.

  2A to 2C, the optical recording medium having a relatively thick optical information recording layer can be easily produced at low cost, and the optical information recording layer can be manufactured. This is advantageous in that the film thickness can be made uniform and the film can be thermocompression-bonded for each layer.

2A to 2C show a method of manufacturing the optical recording medium OM having the three optical recording layers 5a, 5b, and 5c shown in FIG. In the case of manufacturing an optical recording medium having an optical information recording layer composed of four or more optical recording layers, the required number of layers or thickness is obtained by repeating the process shown in FIG. Can be formed.
Moreover, the optical recording medium may contain other layers as required in addition to the optical information recording layer, the support layer, and the adhesive layer. For example, a reflective layer, a dielectric layer, a servo information recording layer, and the like may be included.

  Next, examples and comparative examples of the present invention will be described, but the present invention is not limited to these examples.

(Example 1)
<Adjustment of coating liquid A>
The binder, monomer, polymerization inhibitor (contained in the monomer), sensitizing dye and polymerization initiator shown in Table 1 were weighed under a red lamp and placed in a brown eggplant-shaped flask, and dichloromethane was further added as a solvent. The mixture was stirred for 3 hours using a stirrer to obtain a coating liquid A containing an optical recording material having a formulation shown in Table 1 below. The viscosity of this coating liquid A was 21 [Ps].

note)
CAB531-1: Cellulose acetate butyrate (Eastman Chemical)
POEA: 2-phenoxyethyl acrylate (Cas No. 48145-04-6)
MEHQ: 4-methoxyphenol (Cas No. 150-76-5)
DEAW: cyclopentanone-2,5-bis [[4- (diethylamino) phenyl] methylene] (Cas No. 38394-53-5)
MBO: 2-mercaptobenzoxazole (Cas No. 2382-96-9)
o-Cl-HABI: 2,2-bis [o-chlorophenyl] -4,4,5,5-tetraphenyl-1,1-biimidazole (Cas No. 1707-68-2)

  The coating liquid A was applied on a transparent support (polycarbonate, thickness 80 μm) using a coater having a clearance (gap length) of 300 μm. Next, it was dried at 40 ° C. for 30 minutes to obtain a laminate having an optical recording layer having a thickness of 49 μm. Three laminates were laminated so that optical recording layers and transparent supports were alternately laminated, and punched into a disk shape having a diameter of 12 cm to obtain an optical information recording body. Next, this optical information recording body was bonded to a glass plate (thickness: 1 mm) having a diameter of 12 cm to produce an optical recording medium. At this time, since the monomer was liquid, the laminate could be attached to the glass substrate without using an adhesive layer.

(Example 2)
<Adjustment of coating liquid B>
The binder, acid-decolorable dye, acid generator, and sensitizing dye were weighed under a red lamp and placed in a brown eggplant-shaped flask. Further, a solvent was added and stirred for 3 hours using a stirrer. The coating liquid B containing the optical recording material of the prescription shown in FIG.

PMMA: polymethyl methacrylate (Aldrich, Mw: 996000)
Dye A: quaternary ammonium hydrochloric acid generator A: diphenyliodonium hexafluorophosphoric acid represented by the following formula (a)
(CasNo. 58109-40-3)
Dye B: Ru complex compound represented by the following formula (b)

  The coating liquid B was applied onto a transparent support (polycarbonate, thickness 30 μm) using a coater having a clearance (gap length) of 300 μm. Next, it was dried at 40 ° C. for 30 minutes to obtain a laminate having an optical recording layer having a thickness of 49 μm. Three laminates were laminated so that optical recording layers and transparent supports were alternately laminated, and punched into a disk shape having a diameter of 12 cm to obtain an optical information recording body. Next, this optical information recording body was bonded to a glass plate (thickness: 1 mm) having a diameter of 12 cm to produce an optical recording medium.

  In the optical recording layer formed by the coating liquid B, the sensitizing dye A is excited by the laser in the interference fringe bright portion, and electrons are emitted from the excited dye. The emitted electrons move to the acid generator, and acid is generated from the acid generator. By this acid, dye B (dye decolored by acid) different from the sensitizing dye is decolored, and the refractive index changes. In this way, by decoloring the pigment in the bright part of the interference fringes, refractive index modulation occurs and a hologram is recorded.

(Comparative Example 1)
An optical recording medium having a total optical recording layer thickness of 144 μm was prepared in the same manner as in Example 1 except that a transparent support made of polyethylene terephthalate having a thickness of 5 μm was used and the thickness of each optical recording layer was changed to 48 μm. Manufactured. However, since the support was too thin, streaks occurred frequently at the bonding stage, and diffracted light could not be observed from the obtained optical recording medium.

(Comparative Example 2)
The coating liquid A was applied to the transparent support (polycarbonate, thickness 80 μm) once with a 1 mm clearance blade to obtain a laminate having an optical recording layer having a thickness of 146 μm. At this time, bubbles were generated during drying. This laminate was punched into a disk shape having a diameter of 12 cm and bonded to a glass plate having a diameter of 12 cm (thickness: 1 mm) to produce an optical recording medium. No diffracted light could be observed from this optical recording medium.

<Evaluation>
The diffraction efficiency, thickness, and number of bubbles of the optical recording media obtained in Examples 1-2 and Comparative Examples 1-2 were measured according to the following methods. The results are shown in Table 3.

Measurement of Diffraction Efficiency As shown in FIG. 3, YAG laser light L1 having a wavelength of 532 nm irradiated from the YAG laser source 31 to the surface A of the sample 36 through the objective lens 32, the lens 33, the beam splitter 34, and the mirror 35. The surface of the sample 36 was subjected to saturation exposure with an incident angle of 15 degrees, a spot diameter of 8 mmφ, and a recording energy of 2000 [mJ / cm ² ]. At this time, the He—Ne laser beam L2 having a wavelength of 633 nm is irradiated from the He—Ne laser source 38 through the mirror 39 and the mirror 40 onto the back surface B of the sample 36 at an incident angle of 18 degrees, and the diffraction efficiency with respect to the exposure amount. The change of was observed. At this time, the diffraction efficiency is determined based on the amount of diffracted light of the He—Ne laser measured by the power meter 41 provided on the surface A side of the sample 36 and the amount of incident light of the He—Ne laser incident on the back surface of the sample 36. It was calculated from the following equation from (the amount of light emitted from the He-Ne laser source 38).
Diffraction efficiency (%) = diffracted light quantity / incident light quantity × 100

Thickness The total thickness of the optical information recording layer was measured using DIGITAL MICROMETER made by Sony.

Number of bubbles The optical recording medium was visually observed from the support side, and the number of bubbles per 10 cm ² was measured.

The state of pasting It observed visually and evaluated by the following reference | standard.
○ The surface after bonding is smooth.
× Streaks and wrinkles occur during bonding, and the surface is not smooth.

1 is a schematic cross-sectional view showing a structure of an optical recording medium according to an embodiment of the present invention. (A)-(c) is a figure explaining order for the manufacturing method of the optical recording medium of this invention later on. It is a schematic diagram explaining the measuring method of diffraction efficiency.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Substrate 1a Surface 2 Optical information recording layer 2a 1st optical recording layer 2b 2nd optical recording layer 2c 3rd optical recording layer 3 Support body layer 3a 1st support body layer 3b 2nd support body layer 3c 3rd support body layer 4 Transparent support 5 Optical recording layer 6 Optical recording body 7 Optical information recording body OM Optical recording medium

Claims (7)

  A substrate and an optical information recording layer bonded on the substrate, wherein the optical information recording layer is alternately arranged from the substrate side in the order of an optical recording layer and a transparent support layer having a thickness of 10 to 200 μm. An optical recording medium comprising a plurality of layers formed in the above.   The optical recording medium according to claim 1, wherein the substrate and the optical information recording layer are bonded together by thermocompression bonding.   The optical recording medium according to claim 1, wherein the substrate and the optical information recording layer are bonded together via an adhesive layer.   The optical recording medium according to claim 1, wherein the optical information recording layer is bonded to the substrate by an adhesive component contained in the optical recording layer in contact with the substrate.   The optical recording medium according to any one of claims 1 to 4, further comprising a reflective layer at an interface between the substrate and the optical information recording layer.   6. The optical recording medium according to claim 1, wherein a servo signal recording area is formed on a surface of the substrate that is in contact with the optical recording layer.   An optical recording material is formed on one side of a 10-200 μm transparent support to form an optical recording layer to obtain an optical recording body, and the transparent support and the optical recording layer are alternately disposed. As described above, a step of forming an optical information recording body by bonding a plurality of the optical recording bodies, a step of forming the optical information recording body into a predetermined shape, and forming the optical information recording body into an optical recording layer And a step of bonding the substrate to the substrate so as to be in contact with the substrate.

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