JP2005316279A - Optical recording material, optical recording medium and optical recording reproducing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical recording material containing a polymer compound having a new azobenzene structure which is effective for optical recording with little absorption loss of light, to provide an optical recording medium capable of optical recording in a wide wavelength region and having high-density memory property to record a large amount of data at a high speed, and to provide an optical recording and reproducing apparatus to carry out optical recording and reproducing by using the above recording medium. <P>SOLUTION: The optical recording material contains a polymer compound expressed by general formula (1). In the optical recording medium using the above optical recording material, multiple recording with low scattering, high speed and high sensitivity can be performed even when the recording layer is formed as a thick film for high recording density. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention includes a polymer compound having a specific azobenzene moiety as a photoisomerization group and having the photoisomerization group introduced as a side chain in a specific main chain, so that a large amount of data information can be lighted at high density. The present invention relates to an optical recording material capable of recording, an optical recording medium, and an optical recording / reproducing apparatus.

  In recent years, hologram recording has been actively studied because high-density recording, multiple recording, and the like are possible. As such hologram recording, those using an amplitude hologram that utilizes a change in the transmittance of the recording material, and those utilizing a phase hologram that utilizes a change in the refractive index of the recording material or a change in unevenness are known.

  Among the recording materials used for such hologram recording, many studies have been made on hologram recording materials whose refractive index changes when irradiated with light (hereinafter sometimes referred to as “photorefractive materials”). Organic photorefractive materials have been actively studied because they can be easily processed into an arbitrary shape, and the sensitivity wavelength can be easily adjusted.

  In the photorefractive material, charges are generated by light irradiation, and these are moved and trapped. As a result, an internal electric field is generated, and a refractive index change is caused by the Pockels effect caused by the internal electric field. A hologram is formed by this refractive index change. However, in organic photoactive materials, it is required to orient the molecules in order to effectively exhibit the Pockels effect, which requires an external electric field. The necessity of an external electric field is an important issue in application.

  On the other hand, as a hologram material that does not require an external electric field, an organic material having an azobenzene skeleton as a photoisomerization group is typically known. In the hologram recording, the photoisomerization reaction of azobenzene plays an important role. Irradiating films with these materials with linearly polarized light results in reorientation of azobenzene through a trans-cis-trans isomerization cycle. This orientation change induces optical anisotropy, that is, birefringence and dichroism, and hologram recording can be performed. Thus, an organic material having an azobenzene skeleton is promising as a rewritable optical recording material, particularly a hologram recording material.

  As such a hologram recording material, a hologram recording material using an azobenzene-containing polymer having an azobenzene moiety having a specific structure in the side chain and an acrylate or methacrylate main chain is disclosed (for example, Patent Document 1, 2). However, these are insufficient in sensitivity (recording speed) and recording density for optical recording media.

  In addition, in the technical document, for example, a polymer compound suitable for hologram recording is disclosed, but in order to realize writing in a short time, optical anisotropy is induced over the entire medium in advance. It was necessary and preliminary treatment was necessary. Furthermore, a hologram multiplex recording result using a recording medium having a film thickness of 500 μm is disclosed, but the time required for one hologram recording is 30 seconds, which is not sufficient as a practical recording speed.

As described above, the conventional polymer material containing azobenzene is particularly useful as a volume hologram material for forming a plurality of holograms in an optical recording medium, that is, realizing high diffraction efficiency and high-speed recording of digital data. It is difficult to achieve a thick film medium to be achieved, and a practical medium has a limit of about 40 μm (for example, see Patent Document 3).
JP 2000-514468 Special Table 2002-539476 HJ Coufal, D. Psaltis, GT Sincerbox eds .: Holographic Data Storage, Springer, p.222 (2000)

An object of the present invention is to solve the conventional problems and achieve the following objects.
That is, firstly, an object of the present invention is to provide an optical recording material containing a high molecular compound having a novel azobenzene structure which has little light absorption loss and is useful for optical recording.
A second object of the present invention is to provide an optical recording material capable of high-density optical recording utilizing light absorption change or refractive index change accompanying light or heat.
A third object of the present invention is to provide an optical recording medium capable of optical recording in a wide wavelength range and having a high density memory property capable of recording a large amount of data at high speed.
A fourth object of the present invention is to provide an optical recording medium that has little loss due to light absorption, a low noise level (S / N ratio), and excellent record retention after optical recording.
A fifth object of the present invention is to provide an optical recording medium suitable for hologram recording, which is excellent in modulation by structure photoisomerization and multiple recording properties.
A sixth object is to provide an optical recording / reproducing apparatus that performs optical recording and reproduction using the recording medium.

  As a result of intensive studies by the inventors, the object of the present invention has been achieved by the following means. Specifically, the optical recording material in the present invention includes a polymer compound in which azobenzene having a specific structure is introduced as a side chain of a specific main chain structure as a photosensitive group. It has been found that by using an optical recording medium containing a prescribed optical recording material, a single hologram can be multiplexed and recorded on the order of several hundreds msec, as will be described later.

  Although details of the reason why the above excellent recording characteristics can be obtained are not clear, the structure of azobenzene described in the present invention suppresses absorption in the recording wavelength region (generally about 400 nm to 550 nm) and is oriented with high sensitivity. It is presumed that, due to the effect of the specific main chain structure, it is possible to produce a low scattering thick film medium and to achieve high stability of recording by changing the orientation.

That is, the present invention
<1> An optical recording material comprising a polymer compound represented by the following general formula (1).

In the general formula (1), L ₁ represents a divalent linking group, R ₁ and R ₂ each represents an independent substituent, and R ₃ represents a hydrogen atom or a substituent. b1 represents an integer of 2 to 5, b2 represents an integer of 0 to 4, and a plurality of R _{1 s} or a plurality of R _{2 s} when b2 is 2 or more may be the same or different, and are connected to each other to form a ring. It may be formed. a1 is in the range of 0.0001 to 1, a2 is in the range of 0 to 0.9999, and the sum of a1 and a2 is 1. In addition, n1 represents the integer of the range of 4-2000. A ₁ and A ₂ represent any of the following general formulas (2-1) to (2-4).

The structures represented by the general formulas (2-1) to (2-4) are connected to L ₁ or R ₃ with *. In General Formula (2-1), R _{11 to} R ₁₃ each independently represents a hydrogen atom or a substituent, and L ₁₁ represents —O—, —OC (O) —, —CONR ₁₉ —, —COO— (respectively The left side represents a polymer main chain, the right side is linked to L ₁ or R ₃ ), and an arylene group that may be substituted. R ₁₉ represents a hydrogen atom, an alkyl group, an alkenyl group, a cycloalkyl group, an aryl group, or a heterocyclic group. In General Formula (2-2), R _{14 to} R ₁₆ each independently represent a hydrogen atom or a substituent. In general formulas (2-3) and (2-4), A ₃ and A ₄ each independently represents a trivalent linking group. In General Formula (2-4), R ₁₇ and R ₁₈ each independently represents any of a hydrogen atom, an alkyl group, an alkenyl group, a cycloalkyl group, an aryl group, and a heterocyclic group.

<2> In the optical recording material according to <1>, in the polymer compound represented by the general formula (1), A ₁ and A ₂ are represented by the general formula (2-3). is there.

<3> The optical recording material according to <1>, wherein the polymer compound represented by the general formula (1) is represented by the following general formula (3).

In the general formula _{(3), R 1, R} 2, b1, b2 and n1 are as in formula (1) synonymous. R ₂₁ represents a hydrogen atom or a substituent, L _{12 to} L ₁₄ each independently represents a divalent linking group, and A ₅ represents a trivalent linking group. A3 is in the range of 0.0001 to 1, a4 is in the range of 0 to 0.9999, and the sum of a3 and a4 is 1. a′3 is in the range of 0.0001 to 1, a′4 is in the range of 0 to 0.9999, and the sum of a′3 and a′4 is 1.

<4> A recording layer comprising the optical recording material according to claim 1, wherein information is recorded on the recording layer using at least one of absorption change, refractive index change, and shape change due to light irradiation. This is an optical recording medium.

<5> The optical recording medium according to <4>, wherein hologram recording can be performed by modulating the amplitude, phase, or polarization direction of object light.

<6> When the film thickness of the recording layer is L and the absorption coefficient of the optical recording material is α, the optical density αL represented by the product of the absorption coefficient α and the film thickness L is 0.3 to The optical recording medium according to <5>, which is in a range of 2.0.

<7> The optical recording medium according to <5>, wherein a thickness L of the recording layer is in a range of 20 μm to 10 mm.

<8> An optical recording / reproducing apparatus that records and / or reproduces information using the optical recording medium according to <4>.

<9> The optical recording / reproducing apparatus according to <8>, wherein information is recorded as a hologram in the optical recording medium, and the polarization state of the object light and the reference light at the time of recording is different.

  According to the present invention, an optical recording material and an optical recording medium capable of stably performing multiplex recording with low scattering, high speed, and high sensitivity even when the recording layer is thickened for high density recording, and the same It is possible to provide an optical recording / reproducing apparatus that performs information recording / reproducing by using the.

Hereinafter, the present invention will be described in detail.
<Optical recording material>
First, an optical recording material including a polymer compound having an azobenzene moiety having a specific structure in a side chain and having a main chain structure having a specific structure according to the present invention will be described. The optical recording material of the present invention includes a polymer compound represented by the following general formula (1).

In the general formula (1), the side chain portion bonded to A ₁ represents a group containing a photoresponsive group. The site of the photoresponsive group is preferably a compound site capable of absorbing light and causing a structural change, and the absorbing light is preferably 200 to 1000 nm ultraviolet light, visible light or infrared light, More preferable are ultraviolet rays and visible light of 200 to 700 nm.

  In the present invention, the photoresponsive group is an azobenzene group, and particularly when two or more substituents are bonded to the terminal benzene ring of the azobenzene group, absorption and side in a recording wavelength range of about 400 nm to 550 nm are obtained. By controlling the interaction between the mesogens of the chain, it is possible to change the orientation with high sensitivity, and even when the medium is thickened, it is possible to stably perform multiplex recording with low scattering, high speed and high sensitivity. It was found that it was possible.

In the general formula (1), L ₁ represents a divalent linking group. L ₁ is preferably a simple bond, an alkylene group (preferably having 1 to 20 carbon atoms (hereinafter sometimes referred to as “C number” at the end), for example, methylene, ethylene, Propylene, butylene, pentylene, hexylene, octylene, decylene, undecylene, —CH ₂ PhCH ₂ — (p), etc.), alkenylene groups (preferably having 2 to 20 carbon atoms, eg, ethenylene, propenylene, butadienylene, etc.), An alkynylene group (preferably having a C number of 2-20, such as ethynylene, propynylene, butadienylene, etc.), a cycloalkylene group (preferably having a C number of 3-20, such as 1,3-cyclopentylene, 1, 4-cyclohexylene and the like, an arylene group (preferably having 6 to 26 carbon atoms, -Phenylene, 1,3-phenylene, 1,4-phenylene, 1,4-naphthylene, 2,6-naphthylene, etc.), a heterylene group (preferably having 1 to 20 carbon atoms, for example, pyridine which may be substituted) , Amide, pyrimidine, triazine, piperazine, pyrrolidine, piperidine, pyrrole, imidazole, triazole, thiophene, furan, thiazole, oxazole, thiadiazole, oxadiazole, etc.) Group, ester group, sulfoamide group, sulfonic acid ester group, ureido group, sulfonyl group, sulfinyl group, thioether group, ether group, imino group, carbonyl group, one or more combinations, Preferably in the range of 0-100, more preferably 1-20. Represents a range of linking groups.

In the general formula (1), R ₁ and R ₂ each represents an independent substituent. Preferred examples of the substituent include an alkyl group (preferably having a C number of 1 to 20, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, n-pentyl, benzyl, 3-sulfopropyl. , Carboxymethyl, trifluoromethyl, chloromethyl, etc.), alkenyl groups (preferably having 2 to 20 carbon atoms, such as vinyl, allyl, 2-butenyl, 1,3-butadienyl, etc.), cycloalkyl groups (preferably Has 3 to 20 carbon atoms, such as cyclopentyl, cyclohexyl and the like, and an aryl group (preferably 6 to 20 carbon atoms, such as phenyl, 2-chlorophenyl, 4-methoxyphenyl, 3-methylphenyl, 1 -Naphthyl, etc.), heterocyclic groups (preferably having a C number of 1-20, such as pyridyl, pyrimidyl, Nyl, furyl, thiazolyl, imidazolyl, pyrazolyl, pyrrolidino, piperidino, morpholino, etc.), an alkynyl group (preferably having 2 to 20 carbon atoms, such as ethynyl, 2-propynyl, 1,3-butadiynyl, 2-phenylethynyl Etc.), a halogen atom (for example, F, Cl, Br, I), an amino group (preferably having a C number of 0-20, such as amino, dimethylamino, diethylamino, dibutylamino, anilino, etc.), a cyano group, Nitro group, hydroxyl group, mercapto group, carboxyl group, sulfo group, phosphonic acid group,

  An acyl group (preferably having 1 to 20 carbon atoms, such as acetyl, benzoyl, salicyloyl, pivaloyl, etc.), an alkoxy group (preferably having 1 to 20 carbon atoms, such as methoxy, butoxy, cyclohexyloxy, etc.) An aryloxy group (preferably having a C number of 6 to 26, for example, phenoxy, 1-naphthoxy, etc.), an alkylthio group (preferably having a C number of 1 to 20, for example, methylthio, ethylthio, etc.), an arylthio group (Preferably having 6 to 20 carbon atoms, such as phenylthio, 4-chlorophenylthio, etc.), alkylsulfonyl group (preferably having 1 to 20 carbon atoms, such as methanesulfonyl, butanesulfonyl, etc.), arylsulfonyl A group (preferably having 6 to 20 carbon atoms such as benzenesulfonyl, N-sulfonyl, etc.), sulfamoyl groups (preferably having 0 to 20 carbon atoms, such as sulfamoyl, N-methylsulfamoyl, N-phenylsulfamoyl etc.), carbamoyl groups (preferably having 1 to 20 carbon atoms). Yes, for example, carbamoyl, N-methylcarbamoyl, N, N-dimethylcarbamoyl, N-phenylcarbamoyl, etc.), acylamino group (preferably having 1 to 20 carbon atoms, such as acetylamino, benzoylamino, etc.), imino group (Preferably having 2 to 20 carbon atoms, such as phthalimino), acyloxy groups (preferably having 1 to 20 carbon atoms, such as acetyloxy, benzoyloxy, etc.), alkoxycarbonyl groups (preferably having 2 carbon atoms) -20, for example, methoxycarbonyl, phenoxycarbonyl, etc.), Rubamoiruamino group (preferably a C number of 1 to 20, for example carbamoylamino, N- methylcarbamoyl amino, N- phenylcarbamoylamino, etc.) and the like.

Among these, as R ₁ and R ₂ , alkyl group, cycloalkyl group, aryl group, heterocyclic group, halogen atom, amino group, cyano group, nitro group, hydroxyl group, carboxyl group, alkoxy group, aryloxy group, Alkylsulfonyl group, arylsulfonyl group, sulfamoyl group, carbamoyl group, acylamino group, acyloxy group, alkoxycarbonyl group are more preferable, alkyl group, halogen atom, amino group, cyano group, nitro group, hydroxyl group, carboxyl group, alkoxy group More preferred are an alkylsulfonyl group, a sulfamoyl group, a carbamoyl group, an acylamino group, an acyloxy group, and an alkoxycarbonyl group.

The position where R ₁ and R ₂ are bonded to the substituted benzene ring is not particularly limited, but one of the plurality of R ₁ is bonded to the para position with respect to the bonding position of the azo group. Is preferred.

In the general formula (1), b1 represents an integer of 2 to 5, preferably 2. B2 represents an integer of 0 to 4, preferably represents an integer of 0 to 2, and more preferably represents 0 or 1.
The plurality of R _{1 s} or the plurality of R _{2 s} when b2 is 2 or more may be the same as or different from each other, and may be connected to each other to form a ring. The ring to be formed is preferably a benzene ring, naphthalene ring, pyridine ring, cyclohexene ring, cyclopentene ring, thiophene ring, furan ring, imidazole ring, thiazole ring, isothiazole ring, oxazole ring and the like.

In the benzene ring that can be substituted by R ₂ , the azo group may be substituted at any of the ortho-position, meta-position, and para-position of L ₁ , but is substituted at the ortho-position or para-position. It is more preferable that it is substituted at the position of the para position.

In the general formula (1), R ₃ represents a hydrogen atom or a substituent (examples of preferred substituents are the same as the examples given for R ₁ ), more preferably a hydrogen atom, an alkyl group, an aryl group, A heterocyclic group, a halogen atom, an amino group, a cyano group, a hydroxyl group, a carboxyl group, an alkoxy group, an aryloxy group, an alkylsulfonyl group, an arylsulfonyl group, a carbamoyl group, an acylamino group, an acyloxy group, and an alkoxycarbonyl group.
R ₃ preferably contains one or more of the divalent linking groups mentioned for L ₁ .

In the general formula (1), a1 is in the range of 0.0001 to 1, more preferably in the range of 0.001 to 0.5. Moreover, a2 is the range of 0-0.9999, More preferably, it is the range of 0.5-0.999. The sum of a1 and a2 is 1.
N1 represents an integer of 4 to 2000, more preferably an integer of 4 to 1000.

In the general formula (1), A ₁ and A ₂ represent any of the following general formulas (2-1) to (2-4). In addition, the bond represented by * in the general formulas (2-1) to (2-4) means a bond with L ₁ or R ₃ which is a side chain structure in the general formula (1). The other bond means a bond for constituting the main chain structure.

In general formula (2-1), R _{11 to} R ₁₃ each independently represents a hydrogen atom or a substituent, more preferably a hydrogen atom, an alkyl group, an aryl group, or a cyano group, more preferably a hydrogen atom or methyl. Represents a group, more preferably a hydrogen atom.

In the general formula (2-1), L ₁₁ is —O—, —OC (O) —, —CONR ₁₉ — (each of which is linked to the polymer main chain on the left side and L ₁ or R ₃ on the right side), A good arylene group (preferably having 6 to 26 carbon atoms, for example, 1,2-phenylene, 1,3-phenylene, 1,4-phenylene, 1,4-naphthylene, 2,6- R ₁₉ represents any one of a hydrogen atom, an alkyl group, an alkenyl group, a cycloalkyl group, an aryl group, and a heterocyclic group (the examples of preferred substituents are the same as the examples given as R ₁ ). And preferably represents a hydrogen atom or an alkyl group.

In General Formula (2-2), R _{14 to} R ₁₆ each independently represent a hydrogen atom or a substituent, preferably a hydrogen atom or an alkyl group, and more preferably a hydrogen atom or a methyl group.

In general formulas (2-3) and (2-4), A ₃ and A ₄ each independently represents a trivalent linking group. Note that the preferred structure of A _3, A _4, include the following.

In addition, the bond represented by * of the trivalent linking group mentioned as a preferable structure of A ₃ and A ₄ is a bond with L ₁ or R ₃ which is a side chain structure in the general formula (1). The other bond means a bond for constituting a main chain structure. However, as a preferred structure of A ₃ and A _4, the structure shown as a divalent linking group represents a state in which a hydrogen atom is bonded as R ₃ to the bond indicated by * of A ₃ and A _4. Yes.
Here, R ₃₁ represents a methyl group or a phenyl group, n31 represents an integer of 0 to 2, n32 is an integer of 2 to 12, n33 is an integer of 2 to 12, n34 is 2 to 8 Represents an integer.

In the general formula (2-4), R ₁₇ and R ₁₈ are each independently a hydrogen atom, an alkyl group, an alkenyl group, a cycloalkyl group, an aryl group, or a heterocyclic group (the preferred substituent is the example given as R ₁ above) The same).

A ₁ and A ₂ are more preferably a structure represented by the general formula (2-3).

  Furthermore, it is more preferable that the polymer compound represented by the general formula (1) has a structure represented by the following general formula (3).

In the general formula (3), R ₁ , R ₂ , b1, b2, and n1 have the same meaning as in the general formula (1).

In the general formula (3), in the benzene ring that can be substituted by R ₂ , the azo group may be substituted at any of the ortho-position, meta-position, and para-position of L ₁₂ . More preferably, it is substituted at the position, and further preferably substituted at the para position.

In general formula (3), R ₂₁ represents a hydrogen atom or a substituent (examples of preferred substituents are the same as the examples given for R ₁ ), more preferably hydrogen atoms, alkyl groups, aryl groups, and heterocyclic groups. A halogen atom, an amino group, a cyano group, a hydroxyl group, a carboxyl group, an alkoxy group, an aryloxy group, an alkylsulfonyl group, an arylsulfonyl group, a carbamoyl group, an acylamino group, an acyloxy group, and an alkoxycarbonyl group.
R ₂₁ preferably contains one or more of the divalent linking groups mentioned for L ₁ above.

L _{12 to} L ₁₄ each independently represent a divalent linking group, and preferred examples are the same as the examples given as L ₁₁ .
A ₅ represents a trivalent linking group, and preferred examples are the same as those given as A ₄ .

  a3 is in the range of 0.0001 to 1, and more preferably in the range of 0.001 to 1. A4 is in the range of 0 to 0.9999, more preferably in the range of 0 to 0.999. Note that the sum of a3 and a4 is 1. Moreover, a'3 is in the range of 0.0001 to 1, more preferably in the range of 0.01 to 1. a'4 is in the range of 0 to 0.9999, more preferably in the range of 0 to 0.99. Note that the sum of a'3 and a'4 is 1.

  The number average molecular weight of the polymer compound represented by the general formula (1) in the present invention is preferably from 1,000 to 10,000,000, more preferably from 5,000 to 1,000,000.

  Specific examples of the polymer compound represented by the general formula (1) are shown below, but the polymer compound in the present invention is not limited thereto. In addition, n in each formula represents an integer of 1 or more.

  In addition, the synthesis | combination of the high molecular compound in the above this invention is disclosed by Unexamined-Japanese-Patent No. 2001-294651, Unexamined-Japanese-Patent No. 2000-264962, Special Table 2000-514468, Special Table 2002-539476, etc. The known synthesis method can be referred to.

<Optical recording medium>
(Configuration of optical recording medium and manufacturing method thereof)
Next, the optical recording medium of the present invention will be described in detail.
The optical recording medium of the present invention has at least a recording layer containing the optical recording material as described above, and this recording layer is preferably provided on a substrate (or substrate). A reflective layer can also be provided between the recording layer and the substrate. Further, a protective layer for protecting the recording layer can be provided on the surface of the recording layer opposite to the surface on which the substrate is provided. The protective layer may be a substrate (that is, a configuration in which the recording layer is sandwiched between a pair of substrates). In addition, an intermediate layer may be provided as necessary for the purpose of ensuring adhesion between the substrate and each of the reflective layer, the recording layer, or each of the reflective layer, the recording layer, and the protective layer. .

The shape of the optical recording medium is not particularly limited, and any form such as a disk shape, a sheet shape, a tape shape, or a drum shape can be selected as long as the recording layer is two-dimensionally formed with a constant thickness. can do.
However, from the viewpoint of easily using an existing optical recording medium manufacturing technique and a recording / reproducing system, it is preferable that the disk has a disk shape with a hole in the center as used in a conventional optical recording medium.

-Substrate (base)-
As the substrate and the substrate, various materials can be arbitrarily selected and used as long as the surface is smooth. For example, metal, ceramics, resin, paper, etc. can be used. Moreover, the shape is not particularly limited. In addition, a disk-shaped flat substrate having a hole in the center portion used for a conventional optical recording medium is used from the viewpoint that an existing optical recording medium manufacturing technique and a recording / reproducing system can be easily used. It is preferable.

Specific examples of such substrate materials include glass; acrylic resins such as polycarbonate and polymethyl methacrylate; vinyl chloride resins such as polyvinyl chloride and vinyl chloride copolymers; epoxy resins; amorphous polyolefins; polyesters; And the like, and the like, and may be used in combination as desired. Among the above materials, amorphous polyolefin and polycarbonate are preferable, and polycarbonate is particularly preferable from the viewpoints of moisture resistance, dimensional stability, and low price.
Further, on the surface of the substrate, irregularities (pregrooves) representing information such as tracking guide grooves or address signals may be formed.

  In the case of irradiating the recording layer with light through the substrate during recording or reproduction, a material that transmits the wavelength range of the light to be used (recording light and reproducing light) is used. In this case, it is preferable that the transmittance in the wavelength range of light to be used (in the case of laser light, in the vicinity of the wavelength range where the intensity becomes maximum) is 90% or more.

In the case where a reflective layer is provided on the substrate surface, it is preferable to form an undercoat layer on the substrate surface for the purpose of improving planarity and adhesion.
Examples of the material for the undercoat layer include polymethyl methacrylate, acrylic acid / methacrylic acid copolymer, styrene / maleic anhydride copolymer, polyvinyl alcohol, N-methylol acrylamide, styrene / vinyl toluene copolymer, and chloro. Polymer materials such as sulfonated polyethylene, nitrocellulose, polyvinyl chloride, chlorinated polyolefin, polyester, polyimide, vinyl acetate / vinyl chloride copolymer, ethylene / vinyl acetate copolymer, polyethylene, polypropylene, polycarbonate, etc .; silane coupling Surface modifiers such as agents;

  The undercoat layer is formed by dissolving or dispersing the above materials in an appropriate solvent to prepare a coating solution, and then applying this coating solution to the substrate surface by a coating method such as spin coating, dip coating, or extrusion coating. can do. In general, the thickness of the undercoat layer is preferably in the range of 0.005 μm to 20 μm, and more preferably in the range of 0.01 μm to 10 μm.

-Reflective layer-
The reflective layer is preferably made of a light reflective material having a laser beam reflectance of 70% or more. Examples of such a light reflective material include Mg, Se, Y, Ti, and Zr. , Hf, V, Nb, Ta, Cr, Mo, W, Mn, Re, Fe, Co, Ni, Ru, Rh, Pd, Ir, Pt, Cu, Ag, Au, Zn, Cd, Al, Ga, In , Si, Ge, Te, Pb, Po, Sn, Bi, and the like and semi-metals or stainless steel.
These light reflecting materials may be used alone, or may be used in combination of two or more kinds or as an alloy. Among these, Cr, Ni, Pt, Cu, Ag, Au, Al, and stainless steel are preferable. Particularly preferred is Au, Ag, Al or an alloy thereof, and most preferred is Au, Ag or an alloy thereof.

  The reflective layer can be formed on the substrate, for example, by vapor deposition, sputtering or ion plating of the light reflective material. In general, the thickness of the reflective layer is preferably in the range of 10 nm to 300 nm, and preferably in the range of 50 nm to 200 nm.

-Protective layer-
As the protective layer, a known material can be used as long as it is made of a material and a thickness that can mechanically, physically, and chemically protect the recording layer in a normal use environment. For example, generally, a transparent resin or a transparent inorganic material such as SiO ₂ can be used.
In the case of irradiating the recording layer with light through a protective layer during recording or reproduction, a material that transmits the wavelength range of the light to be used is used. In this case, it is preferable that the transmittance in the wavelength range of light to be used (in the case of laser light, in the vicinity of the wavelength range where the intensity becomes maximum) is 90% or more. This also applies to the intermediate layer provided on the surface on the light incident side of the recording layer for the purpose of improving adhesiveness.

When the protective layer is made of a resin, a resin film made of polycarbonate, cellulose triacetate or the like previously formed into a sheet shape can be used, and the protective layer is formed by bonding the resin film on the recording layer. To do. At the time of bonding, it is preferable to bond through a thermosetting or UV curable adhesive, and to cure the adhesive by heat treatment or UV irradiation in order to ensure adhesive strength. The thickness of the resin film used as the protective layer is not particularly limited as long as it can protect the recording layer, but is practically preferably in the range of 30 μm to 200 μm, more preferably in the range of 50 μm to 150 μm.
Alternatively, the protective layer can be formed by applying and forming a thermoplastic resin, a thermosetting resin, a photocurable resin, or the like instead of such a resin film.

When the protective layer is made of a transparent ceramic or glass material such as SiO ₂ , MgF ₂ , SnO ₂ , or Si ₃ N _4, the protective layer may be formed using a sputtering method, a sol-gel method, or the like. it can. The thickness of the transparent inorganic material formed as the protective layer is not particularly limited as long as it can protect the recording layer, but is practically preferably in the range of 0.1 μm to 100 μm, more preferably in the range of 1 μm to 20 μm.

-Recording layer-
The film thickness L of the recording layer is not particularly limited, but is preferably set so that the optical density αL is in the range of 0.3 to 2.0 when the absorption coefficient of the optical recording material is α. Particularly when used as a hologram recording medium, the film thickness L is preferably in the range of 500 nm to 10 mm, and is determined by the relationship between the interval of interference fringes recorded on the recording layer and the film thickness L of the recording layer. Depending on the type of the hologram recording medium, it is more preferable to set it within the following range.

  That is, when the optical recording medium of the present invention is a planar hologram (when the film thickness L of the recording layer is thin or similar to the interval between the interference fringes recorded on the recording layer), the film thickness L is 500 nm. It is preferably in the range of -100 μm, more preferably in the range of 1 μm to 20 μm.

  On the other hand, when the optical recording medium of the present invention is a volume hologram (when the film thickness L of the recording layer is about the same or several times as large as the interval between the interference fringes recorded on the recording layer), the film thickness L is preferably within a range of 20 μm to 10 mm, and more preferably within a range of 50 μm to 2 mm.

  For forming the recording layer, a known method can be used as appropriate depending on the material used as the recording layer material. For example, liquid phase film formation such as spray method, spin coating method, dipping method, roll coating method, blade coating method, doctor roll method, screen printing method, etc. using a coating solution in which an optical recording material is dissolved, vapor deposition method, etc. Can be used.

However, the thickness of the recording layer formed by these methods is not sufficient for producing the volume hologram type hologram recording medium. In such a case, it is preferable to form a plate-like recording layer using injection molding or hot pressing. When these methods are used, a recording layer having a thickness of 0.1 mm or more can be easily formed.
When an optical recording medium is manufactured using such a plate-like recording layer, the recording layer is sandwiched between a pair of substrates, or the recording layer is thick and has sufficient rigidity and strength. In such a case, the recording layer itself can be used as an optical recording medium.

Next, a method for manufacturing the optical recording medium of the present invention having the above-described configuration, particularly a hologram recording medium will be described more specifically.
When the optical recording medium of the present invention is a planar hologram, it can be produced by sequentially laminating a recording layer or the like on a substrate according to the material used for each layer as described above.

  For example, the main flow of the manufacturing process of an optical recording medium having a configuration in which a recording layer and a protective layer are provided on a substrate will be briefly described as an example. First, a recording layer is formed on a polycarbonate substrate by a spin coating method using a coating solution in which an optical recording material is dissolved in a solvent, and is sufficiently dried. Next, a UV curable adhesive is uniformly applied on the recording layer by a spin coating method, and then the recording layer and a cellulose triacetate resin film for forming a protective layer are bonded together. Thereafter, UV light is irradiated to solidify the adhesive, whereby an optical recording medium having a protective layer / recording layer / substrate configuration can be obtained.

  When the optical recording medium of the present invention is a volume hologram, the optical recording medium is produced as follows in order to form the recording layer by injection molding or hot press sintering as described above. Can do.

  First, when using injection molding, for example, an optical recording medium can be produced as follows. First, a disk-shaped molded product that becomes a recording layer is manufactured by injection molding. Next, the disk-shaped molded product is sandwiched between a pair of disk-shaped transparent substrates and bonded by hot pressing, and hot-melt bonding is performed.

In the injection molding process, the optical recording material as a raw material is heated and melted, and the molten material is injected into a molding die and molded into a disk shape. As the injection molding machine, it is possible to use either an in-line type injection molding machine in which the plasticizing function and the injection function of the raw material are integrated, or a pre-plunger type injection molding machine in which the plasticizing function and the injection function are separated. it can. The injection molding conditions are preferably an emission pressure of 1000 to 3000 kg / cm ² and an emission speed of 5 to 30 mm / sec.
In the hot press process, the thick plate-shaped molded product obtained in the injection molding process is sandwiched between a pair of disk-shaped transparent substrates and hot-pressed under vacuum.

  The optical recording medium produced in this way does not form a recording layer on the substrate, but is formed separately by injection molding, so the recording layer can be easily thickened and suitable for mass production. ing. Also, since the recording layer is bonded to the transparent substrate by hot pressing, the residual distortion of the molded product by injection molding is made uniform, and even if the recording layer is thickened, the recording characteristics are impaired due to the effects of light absorption and scattering. There is no.

  On the other hand, when only hot pressing is used, for example, a hologram recording medium can be manufactured as follows. First, a powdery resin (resin containing the optical recording material of the present invention) is sandwiched between substrates (pressing members) having high releasability such as a Teflon (R) sheet, and in this state, the recording layer is hot-pressed under vacuum. Is molded directly.

In the present invention, the recording layer is preferably formed by vacuum hot pressing. In this case, the powdered resin is loaded as a sample between a pair of pressing members. Next, in order to prevent the generation of bubbles, the temperature is gradually raised to a predetermined temperature under a reduced pressure of about 0.1 MPa, and the sample is pressurized through the pressing member. In this case, it is preferable that the superheating temperature is a temperature equal to or higher than the glass transition temperature (Tg) of the optical recording material, and the pressing pressure is 0.01 to 0.1 t / cm ² . After performing hot pressurization for a predetermined time, heating and pressurization are stopped, and the sample is taken out after being cooled to room temperature.

By performing such hot pressing, the optical recording material sandwiched between the pair of pressing members is heated and melted, and this is cooled to obtain a plate-like recording layer. Finally, the optical recording medium is obtained by removing the pressing member. For example, when a polymer compound having a Tg of about 50 ° C. is used as the optical recording material, the recording layer can be easily formed to a desired thickness by heating to about 70 ° C. and performing hot pressing. Further, no residual distortion occurs in hot pressing.
If necessary, a protective layer or the like may be provided for the purpose of improving the scratch resistance and moisture resistance of the optical recording medium comprising this recording layer.

  In the optical recording medium thus manufactured, the recording layer can be easily thickened. Further, since the recording layer is formed by hot pressing, no residual distortion or the like of the molded product occurs, and even if the recording layer is thickened, the recording characteristics are not impaired due to the effects of light absorption and scattering.

  An optical recording medium of the present invention comprises a recording layer containing the above-mentioned optical recording material, and information is recorded on the recording layer by utilizing at least one of absorption change, refractive index change, and shape change due to light irradiation. An optical recording medium for recording. Examples of the optical recording method include hologram recording, light absorptivity modulation recording, light reflectance modulation recording, and light-induced relief formation. Among these, the optical recording method suitable for the optical recording medium of the present invention is hologram recording.

  In particular, the optical recording medium of the present invention is capable of recording holograms by modulating the amplitude, phase, or polarization direction of object light, and uses high-capacity based on volume recording and parallelism of digital data to be recorded. Also in transfer, it can be used as an excellent optical recording medium.

<Optical recording / reproducing device>
In the optical recording medium of the present invention, it is possible to record a hologram by modulating the amplitude, phase, or polarization direction of object light as described above. However, the polarization directions of incident object light and reference light are parallel to each other. Recording is possible independently in the vertical case. Further, the polarization arrangement of the two light waves at the time of hologram recording is not limited to these, and any arrangement can be selected as long as the light intensity distribution or the polarization distribution due to interference is formed.

FIG. 1 shows a configuration of an example of an optical recording / reproducing apparatus of the present invention.
In this example, a laser diode-pumped solid-state laser having a wavelength of 532 nm is used. The laser beam emitted from the solid-state laser 10 is incident on the polarization beam splitter 12 via the half-wave plate, and is divided into two light waves of signal light and reference light by the polarization beam splitter 12. The signal light is magnified and collimated by the lens system 13 and passes through the spatial light modulator 14. At this time, the data encoded according to the information is expressed by the brightness of the liquid crystal display which is the spatial light modulator 14 and is given to the signal light. Subsequently, the signal light is Fourier-transformed by the lens and is irradiated into the optical recording medium 16. On the other hand, the reference light is converted into a spherical wave by the lens 15 placed immediately before the optical recording medium 16 and irradiated so as to overlap the signal light in the optical recording medium 16. In this manner, interference fringes are formed by the signal light and the reference light in the optical recording medium, and optical anisotropy is induced accordingly, and a hologram is recorded.

  During reproduction, light diffracted by the spherical reference wave is Fourier transformed by a lens, an arbitrary polarization angle component is selected by a polarizing plate, and an image is formed on a CCD camera. The intensity distribution reproduced by the CCD camera is binarized by an appropriate threshold, and the recorded information is reproduced by decoding by an appropriate method.

  The recording device and the reproducing device may be configured integrally as shown in FIG. 1 or may be configured separately. The light source used for reproduction may be the same as the wavelength of the recording light. For example, a helium neon laser having an oscillation wavelength of 633 nm that is insensitive to the recording layer (no absorption) may be used as the light source. . Thereby, non-destructive reading of recorded information becomes possible.

  Here, in the optical recording / reproducing apparatus, binary digital data is recorded / reproduced by the intensity distribution of the signal light, but the encoding method is not limited to this, and multi-value digital data using the intensity distribution is used. May be. The optical recording medium of the present invention can also record the polarization direction of signal light. Therefore, data may be expressed by a binary or multilevel polarization distribution.

  Further, the wavelength of the laser used for recording / reproduction is not limited to this, and a light source having an arbitrary wavelength sensitive to the optical recording material can be used. Further, a mirror device that controls the reflected light direction of the signal light may be used instead of the liquid crystal display, or a CMOS (Complementary Metal-Oxide-Semiconductor) or APS (Active Pixel Sensers) may be used instead of the CCD camera. .

  The reason why the spherical reference wave is used in the exemplified optical recording / reproducing apparatus is to realize volume multiplex recording by a simple method. Recording using the spherical reference wave and moving the recorded medium in the plane direction corresponds to changing the incident angle of the reference light to the effectively recorded hologram. Therefore, volume multiplex recording can be easily realized by recording while shifting the medium while the optical paths of the signal light and the reference light are fixed. The hologram multiplexing method is not limited to this, and known multiplexing methods such as an angle multiplexing method, a wavelength multiplexing method, a correlation multiplexing method, and a polarization multiplexing method can be applied.

Hereinafter, the present invention will be described specifically by way of examples.
<Preparation of optical recording material>
First, polymer compounds 1 to 3 used as an optical recording material were synthesized. Structural formulas (P-40 to P-42) of polymer compounds 1 to 3 are shown below.

(Synthesis of various monomers)
-Monomer 1 constituting the side chain (5- {6- [4- (3 ', 4'-dimethylphenylazo) phenoxy] hexyloxy} isophthalic acid diethyl)-
(1) Synthesis of 4-hydroxy-3 ′, 4′-dimethylazobenzene Into a 3 liter beaker, 750 ml of 6N hydrochloric acid was added, and 122 g (1 mol) of finely crushed 3,4-dimethylaniline was added and stirred. Sufficiently suspended, about 300 g of ice was added here, and the system was cooled. Into this suspension, 400 ml of a sodium nitrite solution in which 80 g (1.16 mol) of sodium nitrite was dissolved in 500 ml of water was added over about 20 minutes. Stir. Further, 94 g (1 mol) of phenol dissolved in 1 liter of 2N potassium hydroxide solution was gradually added to the solution, and the mixture was reacted overnight. The precipitate produced after completion of the reaction was filtered off and dried under reduced pressure to obtain 210 g (almost quantitative) of crude 4-hydroxy-3 ′, 4′-methylazobenzene. This was used in the next reaction without any further purification. The maximum absorption wavelength (λ _max ) of this compound was 345 nm.

(2) Synthesis of 4- (6-bromohexyloxy) -3 ′, 4′-dimethylazobenzene The 4-hydroxy-3 ′, 4′-methylazobenzene was added to a 2-liter three-necked flask equipped with a mechanical stirrer. 45.4 g (0.2 mol), 448 g (2 mol) of 1,6-dibromohexane, and 212 g (1.5 mol) of anhydrous potassium carbonate were added, and 800 ml of acetone was added and stirred to be suspended. This reaction system was heated until acetone was refluxed to react hydroxyazobenzene with bromoalkane. After reacting for 20 hours, insoluble salts were removed by filtration, and the reaction solution was concentrated to about 1/3 with a rotary evaporator.

  When this system was cooled in a refrigerator, 4- (6-bromohexyloxy) -3 ', 4'-dimethylazobenzene crystallized out. The product was filtered, washed successively with a small amount of cold acetone, cold ether and n-hexane, dried under reduced pressure, and crude 4- (6-bromohexyloxy) -3 ′, 4′-dimethylazobenzene 38. 2 g was obtained (yield: 47.8%). This was recrystallized from ethanol to obtain 32 g of 4- (6-bromohexyloxy) -3 ', 4'-dimethylazobenzene (yield: 40.0%). From the analysis by high performance liquid chromatography, the purity of this compound was 98% or more.

(3) Synthesis of diethyl 5-hydroxyisophthalate 182.4 g (1 mol) of 5-hydroxyisophthalic acid, 1500 ml of ethanol, and 10 ml of concentrated sulfuric acid were placed in a 2-liter three-necked flask and refluxed for 24 hours using a water bath. Reacted. After completion of the reaction, the reaction solution was concentrated to about ½ with a rotary evaporator. The obtained solution was poured into about 20% cold aqueous sodium hydrogen carbonate solution to obtain a white lump-like precipitate. This was filtered and dried under reduced pressure to obtain 229 g of crude diethyl 5-hydroxyisophthalate (yield: 96%). Furthermore, recrystallization from ethanol gave 190 g of diethyl 5-hydroxyisophthalate (yield: 80%).

(4) (Synthesis of diethyl 5- {6- [4- (3 ′, 4′-dimethylphenylazo) phenoxy] hexyloxy} isophthalate)
In a 1-liter three-necked flask, 16.6 g (0.07 mol) of diethyl 5-hydroxyisophthalate, 27.2 g (0.07 mol) of 4- (6-bromohexyloxy) -3 ′, 4′-dimethylazobenzene And 15.1 g (0.11 mol) of anhydrous potassium carbonate were added, and 300 ml of acetone was added thereto. This system was heated to reflux for 24 hours to be reacted. After completion of the reaction, the system was poured into 1500 ml of cold water, the precipitate was filtered off and dried under reduced pressure, and crude 5- {6- [4- (3 ′, 4′-dimethylphenylazo) phenoxy] hexyloxy} isophthalate diethyl Got.

This compound was recrystallized twice from acetone, and 5- {6- [4- (3 ′, 4′-dimethylphenylazo) phenoxy] which is monomer 1 constituting the photoresponsive side chain portion of the target product. Hexyloxy} diethyl isophthalate (32.0 g, yield: 85.8%) was obtained. From the analysis by high performance liquid chromatography, the purity of this compound was 98% or more. Moreover, the infrared absorption spectrum (IR) was measured about the obtained compound. The measurement results are shown below.
Characteristic IR absorption peaks: 2937 cm ⁻¹ (CH stretching), 1717 cm ⁻¹ (ester C = 0), 1601 cm ⁻¹ (C═C), 1580 cm ⁻¹ (N═N), 1246 cm ⁻¹ (C—O) -C)

-Monomer 2 constituting the side chain portion (diethyl 5- {6- [4- (4'-cyanophenyl) phenoxy] hexyloxy} isophthalate)-
(1) Synthesis of 4- (6-bromohexyloxy) -4′-cyanobiphenyl 4-hydroxy-4′-cyanobiphenyl 39 g (0.2 mol), 1,6-dibromohexane 487.5 g (2 mol), anhydrous 200 g (1.45 mol) of potassium carbonate and 800 ml of acetone were put into a 2 liter three-necked flask equipped with a mechanical stirrer and refluxed for 20 hours using a water bath. After cooling to room temperature, insoluble salts were removed by filtration. After concentrating the reaction solution to about ½ using a rotary evaporator, 500 ml of hexane was added and stirred with heating. Thereafter, it is gradually cooled to room temperature, further left to stand in a freezer for crystallization, suction filtration, washed with n-hexane and dried under reduced pressure to obtain 61.3 g of crude 4- (6-bromohexyloxy) -4′-cyanobiphenyl. Obtained (yield: 85%). Further, this was recrystallized from ethanol to obtain 41.8 g of purified 4- (6-bromohexyloxy) -4′-cyanobiphenyl (yield: 58%).

(2) Synthesis of diethyl 5- {6- [4- (4'-cyanophenyl) phenoxy] hexyloxy} isophthalate 28.8 g (0.08 mol) of 4- (6-bromohexyloxy) -4'-cyanobiphenyl ), 16.6 g (0.08 mol) of diethyl 5-hydroxyisophthalate synthesized as described above, 19.2 g (0.12 mol) of anhydrous potassium carbonate, and 400 ml of acetone were put into a 1-liter three-necked flask, The reaction was refluxed for 24 hours using a water bath. After cooling, this was poured into about 4 l of pure water, the precipitate was filtered and dried under reduced pressure, and 37 g of crude 5- {6- [4- (4′-cyanophenyl) phenoxy] hexyloxy} isophthalate diethyl (Yield: 90%) was obtained. Thereafter, this was recrystallized from acetone, and diethyl isophthalate (5- {6- [4- (4′-) carrying a cyanobiphenyl via a hexyl group, which is a monomer 2 constituting the side chain portion of the target compound). 30 g of (cyanophenyl) phenoxy] hexyloxy} isophthalate diethyl) were obtained (yield: 73%). About the obtained compound, as a result of performing mass spectrometry (Mass Spectrometry), the peak corresponding to molecular weight 515.6 was confirmed.

-Monomer 1 constituting the main chain (6,6 '-(4,4'-sulfonyldiphenylenedioxy) dihexanol)-
In a 2 liter three-necked flask, 82.3 g (0.3 mol) of 4,4′-sulfonyldiphenol, 90.2 g (0.66 mol) of 6-chloro-1-hexanol, and 97 g of anhydrous potassium carbonate (0. 7 mol) was added, and 250 ml of N, N-dimethylformamide was added and stirred for suspension. The system was then heated to 160 ° C. using an oil bath and allowed to react for 24 hours. Thereafter, the white powdery substance produced by adding it to water containing a small amount of hydrochloric acid was filtered off and dried to obtain crude 6,6 ′-(4,4′-sulfonyldiphenylenedioxy) dihexanol. This was recrystallized from a water-N, N-dimethylformamide system, and 120 g of 6,6 ′-(4,4′-sulfonyldiphenylenedioxy) dihexanol, which is monomer 1 constituting the purified main chain portion, was obtained. Obtained (yield: 89%). The obtained compound was measured for infrared absorption spectrum (IR), and the following results were obtained.
Characteristic IR absorption peaks: 2937 cm ⁻¹ (CH stretching), 1594 cm ⁻¹ (C═C), 1252 cm ⁻¹ (C—O—C), 1149 cm ⁻¹ (S═O)

-Main chain monomer 2 (6,6 '-(4,4'-oxydiphenylenedioxy) dihexanol)-
In a 2 liter flask, 60.66 g (0.3 mol) of 4,4′-oxydiphenol, 90.16 g (0.66 mol) of 6-chloro-1-hexanol, and 97 g (0.7 mol) of anhydrous potassium carbonate were added. Then, 250 ml of N, N-dimethylformamide was added and mixed, heated to 160 ° C. using an oil bath, and reacted for 24 hours. Thereafter, the reaction solution was poured into water containing a small amount of hydrochloric acid, and the precipitate was filtered and dried under reduced pressure to obtain a crude product. Further, this was recrystallized from water, N, N-dimerformamide (substantially quantitative), and 6,6 ′-(4,4′-oxydiphenylenedioxy) which is monomer 2 constituting the main chain portion. ) Dihexanol was obtained. The melting point of the obtained compound was 119 ° C. When the infrared absorption spectrum (IR) was measured, the following results were obtained.
Characteristic IR absorption peaks: 3312.1 cm ⁻¹ (OH), 2936.1 cm ⁻¹ (CH stretching), 1505.2 cm ⁻¹ (aromatic CH), 1241.9 cm ⁻¹ (C—O—C)

(Synthesis of polymer compounds)
-Polymer Compound 1 (Exemplary Compound P-40)-
5- {6- [4- (3 ′, 4′-dimethylphenylazo) phenoxy] hexyloxy} diethylisophthalate 4.65 g (0.0085 mol), 5- {6- [4- (4′-cyanophenyl) ) Phenoxy] hexyloxy} diethyl isophthalate 0.77 g (0.0015 mol), 6,6 ′-(4,4′-oxydiphenylenedioxy) dihexanol 3.62 g (0.009 mol), 6,6 ′ -0.45 g (0.001 mol) of (4,4'-sulfonyldiphenylenedioxy) dihexanol and 0.1 g of anhydrous zinc acetate are put into a 300 ml three-necked flask equipped with a vacuum pressure reducing device and a stirring device. The mixture was reacted at 160 ° C. for 2 hours and at about 1333 Pa for 20 minutes while stirring and heating in a nitrogen atmosphere. Next, the temperature was raised to 180 ° C. while gradually reducing the system pressure to 267 Pa over 30 minutes. After completion of the reaction, it was dissolved in chloroform, and the solution was poured into methanol to precipitate a crude polymer. This was reprecipitated once more, then boiled and washed with hot methanol and hot water, filtered and dried under reduced pressure, and a polyester (polymer compound) having the side chain part 1 (photoresponsiveness) and the side chain part 2 1) was obtained (yield: 82%). The number average molecular weight of the obtained polyester was 8250.

-Polymer compounds 2 and 3 (Exemplary compounds P-41 and P-42)-
Polymer compounds 2 and 3 shown as exemplary compounds P-41 and P-42 were synthesized by the same means as the synthesis method described above.
The number average molecular weights of the obtained polymer compounds 2 and 3 were 9650 and 11150, respectively.

<Preparation of optical recording medium>
Appropriate amounts of flaky polymer compounds 1, 2, and 3 were placed as optical recording materials on three washed glass substrates, and a glass substrate was placed thereon. Next, sandwich type glass cell media (optical recording media 1, 2, and 3) in which the optical recording material was sandwiched between two glass substrates were produced by hot pressing at a temperature of 70 ° C. under reduced pressure. The film thickness of the recording layer in each optical recording medium was 500 μm. The film thickness was controlled by using a film having a thickness equal to the film thickness as a spacer. Furthermore, a transparent uniform film free from scattering and bubbles could be obtained by heating and quenching to 150 ° C.

The optical densities αL (wavelength: 532 nm) of the produced optical recording media 1, 2, and 3 were 0.58, 0.79, and 0.83, respectively.
The optical density αL of the recording layer was obtained using the following formula (1).
_{^{i = i 0 e - α L}} ··· formula (1)

In equation (1), i ₀ represents the intensity of incident light (light perpendicular to the recording layer), and i represents transmitted light (perpendicular to the recording layer and passed through the recording layer). (Alpha) represents the absorption coefficient of the recording layer material, and L represents the film thickness of the recording layer.
Accordingly, the optical density αL can be obtained by measuring the intensity i _{0 of the} incident light and the intensity i of the transmitted light and substituting the obtained values into the equation (1). Furthermore, if the film thickness L is known, the absorption coefficient α can be obtained.

<Optical recording characteristics>
Digital data was recorded / reproduced using the optical recording / reproducing apparatus shown in FIG. Note that a spherical reference wave shift multiplexing method was used for optical recording.
First, the medium shift selectivity was confirmed. As a result, when any of the optical recording media 1 to 3 having a recording layer thickness of 500 μm was used, a plurality of crosstalks were obtained by moving the medium by 25 μm in any optical recording medium. Multiple holograms could be recorded. Therefore, since the area for recording one hologram is 5 mm, it was found that 200 digital data pages can be multiplexed by performing hologram recording while moving the optical recording medium by 25 μm.

Next, for each optical recording medium, multiplex recording was performed with 800 × 660 pixels of the spatial light modulator as one page. The recording light intensity at this time was 200 mW / cm ² . As a result, on any optical recording medium, the recorded digital data could be reproduced by binarizing and decoding the reproduced two-dimensional digital data page with an appropriate threshold.

At this time, when the recording time per page at which the bit error rate that can be corrected by the existing method is 1 × 10 ⁻³ or less was confirmed, 210 msec, 170 msec, And 165 msec.
From this result, it is understood that the optical recording medium using the optical recording material of the present invention can perform multiplex recording with low scattering, high speed and high sensitivity even when the recording layer is made thicker for higher recording density. It was.

It is the schematic which shows an example of the optical recording / reproducing apparatus of this invention.

Explanation of symbols

10, 20 Laser diode pumped solid state laser 11, 21, 31, 42 1 / 2λ plate 12, 22, 36 Polarizing beam splitter 14 Spatial light modulator 16, 24, 34 Optical recording medium 19 CCD camera

Claims (9)

An optical recording material comprising a polymer compound represented by the following general formula (1).

(In the above general formula (1), L ₁ represents a divalent linking group, R ₁ and R ₂ each represent an independent substituent, R ₃ represents a hydrogen atom or a substituent. B1 represents an integer of 2 to 5, b2 represents an integer of 0 to 4, and a plurality of R _{1 s} or a plurality of R _{2 s} when b2 is 2 or more may be the same or different, and may be connected to each other to form a ring. The range of 0.0001 to 1, a2 is in the range of 0 to 0.9999, and the sum of a1 and a2 is 1. Note that n1 represents an integer in the range of 4 to 2000. A ₁ , A ₂ represents any one of the following general formulas (2-1) to (2-4).

(The structures shown in the general formulas (2-1) to (2-4) are connected to L ₁ or R ₃ with *. In the general formula (2-1), R _{11 to} R ₁₃ are respectively Independently represents a hydrogen atom or a substituent, and L ₁₁ represents —O—, —OC (O) —, —CONR ₁₉ —, —COO— (the left side is linked to the polymer main chain, and the right side is linked to L ₁ or R ₃ . And R ₁₉ represents an optionally substituted arylene group, wherein R ₁₉ represents any one of a hydrogen atom, an alkyl group, an alkenyl group, a cycloalkyl group, an aryl group, and a heterocyclic group. R _{14 to} R ₁₆ each independently represents a hydrogen atom or a substituent, and in formulas (2-3) and (2-4), A ₃ and A ₄ each independently represents a trivalent linking group. . in the general formula _{(2-4), R 17, R} 18 each independently represent a hydrogen atom, an alkyl group, an alkenyl group, shea Roarukiru group, an aryl group, or a heterocyclic group.) _2. The optical recording material according to claim 1, wherein in the polymer compound represented by the general formula (1), A ₁ and A ₂ are represented by the general formula (2-3). The optical recording material according to claim 1, wherein the polymer compound represented by the general formula (1) is represented by the following general formula (3).

(In the above general formula (3), R ₁ , R ₂ , b 1, b 2 and n 1 have the same meaning as in general formula (1). R ₂₁ is a hydrogen atom or a substituent, and L _{12 to} L ₁₄ are each independently 2 A valent linking group, A ₅ represents a trivalent linking group, a3 is in the range of 0.0001 to 1, a4 is in the range of 0 to 0.9999, and the sum of a3 and a4 is 1. A′3 is in the range of 0.0001 to 1, a′4 is in the range of 0 to 0.9999, and the sum of a′3 and a′4 is 1.)   A recording layer comprising the optical recording material according to claim 1, and recording information on the recording layer using at least one of absorption change, refractive index change, and shape change due to light irradiation. A characteristic optical recording medium.   The optical recording medium according to claim 4, wherein hologram recording can be performed by modulating the amplitude, phase, or polarization direction of the object light.   When the film thickness of the recording layer is L and the absorption coefficient of the optical recording material is α, the optical density αL represented by the product of the absorption coefficient α and the film thickness L is 0.3 to 2.0. The optical recording medium according to claim 5, wherein the optical recording medium is in the range.   6. The optical recording medium according to claim 5, wherein a thickness L of the recording layer is in a range of 20 [mu] m to 10 mm.   An optical recording / reproducing apparatus for recording and / or reproducing information using the optical recording medium according to claim 4.   9. The optical recording / reproducing apparatus according to claim 8, wherein information is recorded as a hologram in the optical recording medium, and the polarization state of the object light and the reference light at the time of recording is different.

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