JPH06309694A - Information recording medium - Google Patents

Abstract

PURPOSE:To obtain excellent smoothness, solvent resistance and strength and excellent adhesion property with an electrode layer by forming a polyfunctional UV-curing resin layers on both surfaces of a plastic sheet to constitute a plastic substrate. CONSTITUTION:The plastic substrate consists of a plastic sheet 15 and polyfunctional UV-curing resin layers 17 formed on at least both surfaces of the sheet 15. On this substrate, an information recording layer comprising an electrode layer 13, liquid crystal phase 11', and resin phase 11'' is successively formed. The surface of the obtd. recording medium where the electrode is deposited is treated with plasma. Thereby, the obtd. information recording medium has good smoothness without roughness or warpage, a high electric resistance, high strength which prevents scratches on the back surface, and excellent solvent resistance. The information recording layer is made to have a skin layer so that blotting of the liquid crystal is prevented and that the obtd. medium enables high-sensitive high-contrast information recording without noise.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information recording medium having a plastic substrate, which has a plastic substrate excellent in adhesiveness with an electrode layer, excellent in smoothness without warpage, strength, and solvent resistance. The present invention relates to an information recording medium.

[0002]

2. Description of the Related Art Recently, a liquid crystal cell in which a liquid crystal layer is a polymer dispersion type liquid crystal has been developed, and such a medium is held in a state of being sandwiched between two substrates having ITO (indium tin oxide) electrodes. However, an information recording medium in which this medium has a structure of substrate / ITO electrode / polymer dispersed liquid crystal layer has been developed.

In this information recording medium, the liquid crystal can be aligned and recorded according to the information light by the exposure under the voltage application in the state of facing the photoconductor, and the liquid crystal is formed on the surface of the polymer dispersed liquid crystal layer. However, there is a problem in that the phenomenon of bleeding out of the image occurs and causes noise when recording information. Also, when information is recorded by aligning the liquid crystal layer by applying a voltage between both electrodes in the structure of substrate / ITO electrode / polymer dispersion type liquid crystal layer / ITO electrode, the ITO of the surface layer is also spilled due to the seepage of liquid crystal.
There is a problem in that the electrodes are cracked, floated, and the like, and the conductivity is lowered.

The applicant of the present invention uses a UV curable resin as a resin for forming the information recording layer in this type of medium, so that the inside of the information recording layer has a structure in which a liquid crystal phase and a UV curable resin phase are dispersed. It was found that the outer surface of the resin layer could be used as an ultraviolet-curing resin skin layer, and the application was filed earlier (Japanese Patent Application No. 4-24580). Since the surface of this information recording layer is formed only of the resin layer, liquid crystal bleeding phenomenon does not occur, noise-free recording can be performed in information recording using an optical sensor, and sputtering is performed on the resin layer. This makes it possible to directly form an electrode layer such as an ITO film.

However, when a plastic plate is used as the substrate in such an information recording medium, there is a problem that the heating means used in the manufacturing process warps the information recording medium and loses its smoothness. In addition, depending on the solvent used, the substrate may become cloudy, which causes noise when recording or reproducing information with transmitted light.
In addition, depending on the plastic substrate, there is a problem that the strength is low and scratches or the like occur, resulting in information noise.

[0006]

The present invention relates to an improvement in an information recording medium having a plastic substrate of this kind, which is excellent in smoothness, solvent resistance, strength, and adhesion to an electrode layer. An object is to provide an information recording medium having plastic.

[0007]

The first information recording medium of the present invention is an information recording medium in which an information recording layer consisting of an electrode layer, a liquid crystal phase and a resin phase is sequentially laminated on a plastic substrate. The substrate is characterized in that at least the front and back surfaces of the plastic sheet each have a coating layer made of a polyfunctional UV-curable resin layer, and the electrode laminated surface is plasma-treated.

The second information recording medium of the present invention is an information recording medium in which an electrode layer, a photoconductive layer, an information recording layer composed of a liquid crystal phase and a resin phase, and an electrode layer are sequentially laminated on a plastic substrate. The plastic substrate has a coating layer made of a polyfunctional UV-curable resin layer on at least both front and back surfaces of a plastic sheet, and the electrode laminated surface is plasma-treated.

FIG. 1A is a diagram for schematically explaining a cross section of a first information recording medium of the present invention, in which 3 is an information recording medium, 11 is an information recording layer, and 13 is an electrode layer. , 15 is a plastic sheet, and 17 is a polyfunctional UV curable resin layer.

In the information recording medium of the present invention, information is stored as visible information in the information recording layer made of polymer dispersed liquid crystal, and the recorded information is reproduced by transmitted light or reflected light. It is necessary to meet the following requirements.

(1) The information recording medium is required to be smooth, have no unevenness or warp, and should be within ± 1 mm within 1 m ² . In the present invention, since the coating liquid is used to form the information recording layer, the coating layer is subjected to an operation such as a drying treatment at a high temperature and an ultraviolet ray irradiation. The phenomenon such as warp tends to occur.

(2) It has an electric resistance value of at least 1 × 10 ⁹ Ω · cm at 25 ° C.

(3) Since the information is also reproduced by transmitted light, it is required that the back surface of the substrate is free from scratches and the like, and has a pencil hardness of H or more under a 1000 g load. (3) When the information recording layer is laminated by using a coating solution using a solvent, if the solvent has solubility in plastic, the solvent wraps around the back surface of the substrate during coating and the substrate becomes cloudy. However, since it may cause noise in the recorded information, at least the surface of the substrate needs to be insoluble in, for example, chloroform.

In order to satisfy such a problem, as a result of extensive studies, it is assumed that the plastic substrate of the present invention is provided with a coating layer made of a multifunctional ultraviolet curable resin layer 17 on at least both front and back surfaces of the plastic sheet 15. We have found that this can be solved.

The plastic sheet may have a film shape, a tape shape, a card shape, a disk shape, or the like, and may be transparent or opaque. Polyethylene, polypropylene, polyethylene terephthalate, polymethylmethacrylate, poly Methyl acrylate, and as a commercial product, for example, trade name "ARTO
A plastic sheet such as N "(manufactured by Japan Synthetic Rubber Co., Ltd.) can be used. The film thickness is not particularly limited, but a film thickness of 0.4 mm or more is required in consideration of the supportability for the information recording medium. When the information recording medium is a film, the film thickness may be 30 μm to 200 μm.

Next, the polyfunctional UV-curable resin layer covers at least both front and back surfaces of the plastic sheet, and a solution prepared by dissolving the polyfunctional UV-curable resin monomer or oligomer and the photopolymerization initiator in a solvent is used. It is formed by dip-coating a plastic sheet and irradiating the coating layer with ultraviolet rays to cure.

Examples of the polyfunctional UV-curable resin monomer or oligomer include dipentaerythritol hexaacrylate, trimethylolpropane triacrylate, polyethylene glycol diacrylate, polypropylene glycol diacrylate, isocyanuric acid (ethylene oxide modified) triacrylate, and dipenta. Examples thereof include polyfunctional monomers such as erythritol pentaacrylate, dipentaerythritol tetraacrylate, neopentyl glycol diacrylate, and hexanediol diacrylate, and polyfunctional urethane-based compounds. For example, PPZ and U-1000 manufactured by Idemitsu Co., Ltd. , Toagosei Kagaku Co., Ltd. M-8030, Nippon Kayaku Co., Ltd. DPR-047, DPR-044, ARC-87 etc. are mentioned.

Examples of the solvent include aromatic hydrocarbon solvents such as xylene, halogenated hydrocarbon solvents such as chloroform, alcohol derivative solvents such as methyl cellosolve, and ether solvents such as dioxane. A solvent etc. are mentioned.

As the photo-curing agent, for example, 2-hydroxy-2-methyl-1-phenylpropan-1-one (“Darocur 1173” manufactured by Ciba-Geigy), 1-
Hydroxycyclohexyl phenyl ketone (“Irgacure 184” manufactured by Ciba Geigy), 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropan-1-one (“Darocur 111 manufactured by Ciba Geigy”)
6 "), benzyl dimethyl ketal (" Irgacure 651 "manufactured by Ciba-Geigy), 2-methyl-1- [4-
(Methylthio) phenyl] -2-morpholinopropanone-1 (“Irgacure 907” manufactured by Ciba-Geigy),
A mixture of 2,4-diethylthioxanthone ("Kayacure DETX" manufactured by Nippon Kayaku Co., Ltd.) and ethyl p-dimethylaminobenzoate ("Kayacure EPA" manufactured by Nippon Kayaku Co., Ltd.),
Isopropyl thioxanthone (a mixture of "Kunta Cure ITX" manufactured by Ward Brekinsop Co., Ltd.) and ethyl p-dimethylaminobenzoate can be used.

The polyfunctional ultraviolet curable resin layer thus formed has an electric resistance value of at least 1 × 10 ⁹ Ω · cm at 25 ° C., and 1000 g.
It has a hardness of H or more in terms of pencil hardness under load and is excellent in solvent resistance.

The thickness of the polyfunctional UV-curable resin layer is not particularly limited, but when the information recording medium is in the form of a film or tape, that is, the thickness of the plastic sheet is 30 μm to.
In the case of 200 μm, 1% to 5% of the film thickness
When it is in the range of 0%, it is possible to maintain the smoothness when used as an information recording medium.

When reproducing information with transmitted light, it is necessary that the electrodes and the substrate have transparency. In that case, the other surface of the substrate on which the electrode layer is provided may be, if necessary, The antireflection property may be imparted by laminating a layer having an antireflection effect, adjusting the transparent substrate to a film thickness capable of exhibiting the antireflection effect, or further combining them. In the case of reproducing information by reflected light, the electrode may be a metal thin film layer having reflectivity, or a light reflecting layer such as a metal thin film may be laminated on the substrate surface.

Next, when laminating the electrode layer on the plastic substrate, the surface of the substrate is subjected to plasma treatment for the purpose of providing adhesion to the electrode layer. As the plasma treatment, a low temperature plasma method, a low pressure glow discharge method or the like which is usually employed in surface treatment of plastics can be adopted, and it is preferable to perform it in at least one plasma atmosphere selected from inert gas, oxygen and hydrogen. .

The electrode layer 13 is formed on the plasma-treated substrate.
Are stacked. The electrode layer needs to be transparent when reproducing information with transmitted light, and may be opaque when reproducing information with reflected light, but the metal thin film conductive film has a specific resistance value of 10 ⁶ Ω · cm or less. , An inorganic metal oxide conductive film such as indium tin oxide, an organic conductive film such as a quaternary ammonium salt, and the like. Electrode layers are evaporation, sputtering, CVD, coating,
It is formed by a method such as plating, dipping or electrolytic polymerization. In addition, the film thickness is the electrical characteristics of the material forming the electrode,
It is necessary to change the voltage depending on the applied voltage at the time of information recording. For example, the thickness of the ITO film is about 100 to 3000 Å, and it is formed on the entire surface between the information recording layer and the pattern of the information recording layer.

The information recording layer 11 is composed of a liquid crystal phase and a resin phase, and the liquid crystal material is a smectic liquid crystal,
A nematic liquid crystal, a cholesteric liquid crystal, or a mixture thereof can be used, but it is preferable to use a smectic liquid crystal from the viewpoint of so-called memory property that retains the orientation of the liquid crystal and permanently retains information.

As the smectic liquid crystal, a liquid crystal substance exhibiting a smectic A phase such as a cyanobiphenyl type, a cyanoterphenyl type, a phenyl ester type, or a fluorine type having a long terminal carbon chain of a substance exhibiting liquid crystallinity, a ferroelectric substance A liquid crystal substance exhibiting a smectic C phase used as a liquid crystal,
Alternatively, a liquid crystal substance exhibiting smectic H, G, E, F or the like can be given. A nematic liquid crystal may be used, and the memory property can be improved by mixing with a smectic or cholesteric liquid crystal, and examples thereof include a Schiff base type, an azoxy type, an azo type, a benzoic acid phenyl ester type, and a phenyl cyclohexylate. Known nematic liquid crystals such as ester type, biphenyl type, terphenyl type, phenyl cyclohexane type, phenyl pyridine type, phenyl oxazine type, polycyclic ethane type, phenyl cyclohexene type, cyclohexyl pyrimidine type, phenyl type and tolan type can be used. Also, a microcapsule obtained by mixing polyvinyl alcohol or the like with a liquid crystal material can be used. When selecting a liquid crystal material, it is preferable to use a material having a large anisotropy in the refractive index because the contrast can be obtained.

As a material for forming a resin phase, a solvent-soluble thermosetting resin having compatibility with a liquid crystal material and a common solvent, such as an acrylic resin, a methacrylic resin, a polyester resin, a polystyrene resin, and these are mainly used. The above-mentioned copolymers, epoxy resins, silicone resins, etc. may be used, but ultraviolet curable resins that are compatible with the liquid crystal material in the monomer or oligomer state, or in the monomer or oligomer state Therefore, those having compatibility with the liquid crystal material and the same solvent can be preferably used.

Examples of such UV-curable resins include acrylic acid esters, methacrylic acid esters, etc. In the state of monomers and oligomers, for example, dipentaerythritol hexaacrylate, trimethylolpropane triacrylate, polyethylene glycol diacrylate. Polypropylene glycol diacrylate, isocyanuric acid (ethylene oxide modified) triacrylate, dipentaerythritol pentaacrylate, dipentaerythritol tetraacrylate, neopentyl glycol diacrylate, hexanediol diacrylate, etc. Type, ester type oligomer, further nonylphenol modified acrylate, N-vinyl-2-pyrrolidone,
Examples thereof include monofunctional monomers or oligomers such as 2-hydroxy-3-phenoxypropyl acrylate.

As the solvent, a solvent having a relative evaporation rate to n-butyl acetate of less than 2 is common to the liquid crystal, the ultraviolet-curable resin-forming material, the photocuring agent, and the fluorine-based surfactant. It is necessary to be. The "solvent having a relative evaporation rate with respect to -n-butyl acetate of less than 2" is described, for example, in Yuji Harazaki, "Easy-to-understand coating technology", pages 217 to 221, published by Riko Shuppansha. Volatile at constant temperature, And R is less than 2.

Solvents that can be used in the present invention include
Xylene (R = 0.76), cyclohexanone (R =
0.32) and the like having a relatively slow evaporation rate are preferable,
Further, halogenated hydrocarbon solvents such as chloroform, alcohol derivative solvents such as methyl cellosolve, and ether solvents such as dioxane are also included. In addition, specifically, methyl alcohol,
Denatured ethanol, isopropanol, n-propanol, sec-butanol, isobutanol, n-butanol, methylisobutylcarbinol, diisobutylcarbinol, hexylene glycol, acetic acid-sec-butanol, isobutyl acetate (98%), n-butyl acetate , Methylaluminum acetate, aluminum acetate (95% isomer mixture), ethyl lactate, methyloxitol, ethyloxitol, isopropyloxitol, methyloxitol acetate, ethyloxitol acetate, butyloxitol, methyldioxitol, ethyl Dioxitol, butyldioxitol, butyldioxitol acetate, methyl isobutyl ketone, ethyl amyl ketone, Pent-O-xone (ME-6K), methylcyclohexanone, di Sobuchiruketon, diacetone alcohol, isophorone, 1,4-dioxane, perchlorethylene, dichloropropane, 2-nitropropane,
Toluene, SBP100 / 140, rubber solvent, xylene, SBP140 / 165, SBP6, SBP11, S
hellsolA, white spirit (LAWS),
ShellsolE, ShellsolTD, White Spirit (115 ° F flash), ShellsolT,
Shellsol AB, Distilate, Sol
Vent300, ShellsolN, Shellso
lRA, ShellsolK, ShellsolR, S
olvent350 etc. can be mentioned. If the monomer or oligomer for forming the ultraviolet curable resin is compatible with the liquid crystal itself, it is not necessary to use a solvent, but in order to make the information recording layer a uniform thin film layer, a solvent is used. Is preferably used.

Examples of the photo-curing agent include 2-hydroxy-2-methyl-1-phenylpropan-1-one (“Darocur 1173” manufactured by Ciba Geigy), 1-hydroxycyclohexyl phenyl ketone (manufactured by Ciba Geigy). "Irgacure 184"), 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropane-1
-On (Caro Geigy's "Darocur 111
6 "), benzyl dimethyl ketal (" Irgacure 651 "manufactured by Ciba-Geigy), 2-methyl-1- [4-
(Methylthio) phenyl] -2-morpholinopropanone-1 (“Irgacure 907” manufactured by Ciba-Geigy),
A mixture of 2,4-diethylthioxanthone ("Kayacure DETX" manufactured by Nippon Kayaku Co., Ltd.) and ethyl p-dimethylaminobenzoate ("Kayacure EPA" manufactured by Nippon Kayaku Co., Ltd.),
Isopropyl thioxanthone (a mixture of "Kunta Cure ITX" manufactured by Ward Brekinsop Co., Ltd.) and ethyl p-dimethylaminobenzoate can be mentioned, but it is in a liquid form.
-Hydroxy-2-methyl-1-phenylpropane-1
-One is particularly preferable in terms of compatibility with the liquid crystal material, the polymer-forming monomer or the oligomer.

The content ratio of the liquid crystal to the total amount of the liquid crystal and the resin can be 10% by weight to 90% by weight. When the content of the liquid crystal is less than 10% by weight, the light transmittance is low even if the liquid crystal phase is oriented by the information recording, and when it exceeds 90% by weight, the phenomenon such as exudation of the liquid crystal occurs to cause image unevenness. Not preferable. However, in the information recording medium of the present invention, the proportion of the liquid crystal is preferably 40% by weight to 80% by weight. According to the present invention, since the outer surface of the information recording layer can be a skin layer made of a resin layer, the content of the liquid crystal can be increased, whereby a highly sensitive and high contrast information recording medium can be obtained. The operating voltage can be lowered.

In the information recording layer, the optical refractive index of the liquid crystal phase and the optical refractive index of the resin phase are set to be substantially the same, so that the information recording layer is opaque due to light scattering when no electric field is applied, and the liquid crystal when an electric field is applied. Since the phases are oriented and the information recording portion can be made transparent, the deflecting plate is not required for reproducing information, and the optical system for reading can be simplified.

In the present invention, a fluorine-containing surfactant is added for the purpose of forming a skin layer made of only a resin on the surface of the information recording layer together with the wettability to the electrode layer. Examples of such fluorine-based surfactants include Sumitomo 3M Ltd.'s Florard FC-430, Florard FC-431, N- (n-propyl) -N- (β-acryloxyethyl) -perfluoro. Octyl sulfonic acid amide [Mitsubishi Materials Corp. EF-125M], N
-(N-Propyl) -N- (β-methacryloxyethyl) -perfluorooctylsulfonic acid amide [EF-135M manufactured by Mitsubishi Materials Corporation], perfluorooctanesulfonic acid [EF-10 manufactured by Mitsubishi Materials Corporation]
1], perfluorocaprylic acid [Mitsubishi Materials Corporation
EF-201], N- (n-propyl) -N-perfluorooctanesulfonic acid amide ethanol [EF-121 manufactured by Mitsubishi Materials Corp.], and EF-102 and EF-103 manufactured by Mitsubishi Materials Corp. , The same EF-10
4, the same EF-105, the same EF-112, the same EF-12
1, the same EF-122A, the same EF-122B, the same EF-1
22C, EF-122A3, EF-123A, E
F-123B, same EF-132, same EF-301, same E
F-303, EF-305, EF-306A, E
F-501, EF-700, EF-201, EF
-204, EF-351, EF-352, EF-
801, EF-802, EF-125DS, EF
-1200, EF-L102, EF-L155, EF-L174, EF-L215 and the like. In addition, 3- (2-perfluorohexyl) ethoxy-1,
2-dihydroxy propane [M manufactured by Mitsubishi Materials Corporation]
F-100], Nn-propyl-N-2,3-dihydroxypropyl perfluorooctyl sulfonamide [MF-110 manufactured by Mitsubishi Materials Corporation], 3- (2-
Perfluorohexyl) ethoxy-1,2-epoxypropane [MF-120 manufactured by Mitsubishi Materials Corporation], N-
n-propyl-N-2,3-epoxypropyl perfluorooctyl sulfonamide [MF-130 manufactured by Mitsubishi Materials Corporation], perfluorohexyl ethylene [MF-140 manufactured by Mitsubishi Materials Corporation], N- [3-] Trimethoxysilyl) propyl] perfluoroheptylcarboxylic acid amide [MF-150 manufactured by Mitsubishi Materials Corporation],
N- [3-trimethoxysilyl) propyl] perfluoroheptylsulfonamide [M manufactured by Mitsubishi Materials Corporation]
F-160] and the like. The fluorine-based surfactant is 0.1 to 20% by weight based on the total amount of liquid crystal and resin forming material.
Used in proportion. Further, if necessary, a leveling agent may be added in order to improve the suitability for application of the solution and improve the surface property.

Next, a method for forming the information recording layer will be described step by step. (1) Mixing a liquid crystal, a resin-forming material, a photopolymerization initiator, and a surfactant with a solvent having a relative evaporation rate of less than 2 with respect to -n-butyl acetate to obtain a solid content concentration of 10 to 60% by weight. Use as a solution. Solvent dilution is 1 to 500 cps (2
0 ° C.), preferably 10 to 200 cps (20 ° C.). If the viscosity is low, the coating solution will flow and the film thickness after coating cannot be maintained, and if the viscosity is high, leveling will be difficult. Further, the liquid crystal is heated to a temperature above the temperature at which the liquid crystal retains an isotropic phase, preferably within the temperature range of the isotropic phase transition point + 10 ° C. to dissolve the liquid crystal. At this time, the gelled material, dust and the like of the ultraviolet curable resin forming material present in the solution are removed by filtering. The presence of gelled matter, dust, etc. causes noise as an information recording medium.

Further, the mixed solution is heated to the isotropic phase temperature or higher, but at this time, if the solvent is evaporated and dried, the mixed solution undergoes phase separation and a uniform film is not formed. Therefore, a solvent having a relative evaporation rate with respect to -n-butyl acetate of less than 2 is used as the solvent. If the relative evaporation rate is greater than 2, the evaporation will be too fast and the above problems will occur.
Usually, as long as it can be dissolved by heating up to 70 ° C., there is no problem even if R is 0.3 or more and 1 or less, and xylene (R = 0.7) may be used,
Further, when heating at 70 ° C. or higher is required for dissolution, a solvent having R less than 0.3, for example, cyclohexanone (R = 0.2) may be used.

(2) Next, the mixed solution is applied uniformly on the electrode layer at room temperature by a coating method such as spin coater, bar coat, blade coater, or roll coater.

(3) The coating layer is maintained above the temperature at which the liquid crystal retains the isotropic phase, preferably within the temperature range of the isotropic phase transition point ± 10 ° C., and the solvent is removed by evaporation. The temperature of the coating layer is
When the temperature is lower than the isotropic phase transition temperature by 10 ° C. or more, there arises a problem that the phase separation between the liquid crystal and the ultraviolet curable resin material increases. That is, the liquid crystal domain grows too much, the skin layer is not completely formed on the surface of the information recording layer, liquid crystal bleeding phenomenon occurs, and the ultraviolet curable resin becomes matte, which makes it difficult to accurately capture information. , Not preferable. In addition, the ultraviolet curable resin may not be able to hold the liquid crystal and may not even form the information recording layer. Also, the isotropic phase transition point +1
When the temperature is 0 ° C. or higher, the detailed reason is unknown, but the phase separation between the liquid crystal phase and the resin phase becomes unclear in the information recording layer.

(4) In order to completely remove the solvent, the drying treatment may be carried out in two steps of hood drying and vacuum drying, whereby unevenness of the surface of the information recording layer due to air flow can be prevented. However, interference fringes can be prevented.

(5) Next, the dried coating layer is exposed to UV.
The lamp is used to irradiate it with ultraviolet rays to cure it, but when irradiating the coating layer with ultraviolet rays, it is necessary to block the infrared rays.
An information recording layer excellent in phase separation between a liquid crystal phase and a resin phase is obtained by using ultraviolet rays having a wavelength portion of 00 nm to 400 nm of 1% or more and irradiating with energy of 0.1 mJ / cm ² or more. .

When the information recording layer is formed in this way,
0.01% to 3% of the thickness of the information recording layer on the surface of the information recording layer
A skin layer having a film thickness of 0% is formed, and the inside of the information recording layer has a primary particle diameter of 0.03 μm to 0.
It can have a structure in which resin particles of 3 μm are filled, and a liquid crystal phase communicates between them. When a polyfunctional UV-curable resin material having a parameter represented by the average molecular weight / average functional group of 160 or less is used as the UV-curable resin forming material, the surface skin layer can have excellent durability.

By forming a durable skin layer on the surface of the information recording layer, it is possible to increase the use ratio of the liquid crystal in the information recording layer and to prevent the liquid crystal from seeping out to the surface of the information recording layer. Disturbance of the image due to this can be eliminated, and a high quality image can be obtained.

In the information recording layer, if the phase separation between the liquid crystal phase and the resin phase is incomplete in the fine structure, the problem that the contrast cannot be obtained occurs. Also,
When the phase separation is incomplete, the resistance of the information recording layer itself becomes low, and during the information recording by the action of the electric field by the electrostatic information using the optical sensor, the voltage is not effectively applied to the liquid crystal phase in the information recording layer. However, there is a problem that the liquid crystal drive becomes slow and the sensitivity is lowered. In addition, if the phase separation is incomplete, when the UV curable resin forming material is irradiated with a UV lamp containing infrared rays, unnecessary heating causes non-uniform shrinkage, which is a fatal homogeneous and homogeneous information as an information recording medium. It causes a serious problem that the recording layer cannot be formed.

(6) The average film thickness of the information recording layer thus formed is 1 μm to 30 μm. If the film thickness is too thick, the operating voltage will be high, but generally it is better to make the film thickness thinner to increase the sensitivity and thicker to increase the contrast. In order to have excellent sensitivity and contrast ratio, the film thickness is preferably 3 μm.
The film thickness may be m to 20 μm, and more preferably 5 μm to 10 μm. As a result, the operating voltage can be lowered while maintaining high contrast.

The thickness of the skin layer in the information recording layer can be set to 0.01% to 50% of the thickness of the information recording layer, but if it is too thin, liquid crystal oozes out and its surface will be described later. Even if the information is recorded by the optical sensor, it becomes noise. Therefore, it is preferable that the thickness of the skin layer is 0.01% to 30% of the thickness of the information recording layer. Although the detailed reason is not clear, the film thickness of the skin layer can be appropriately adjusted by the kind of the ultraviolet curable resin, the ultraviolet irradiation amount, the addition of a fluorine-based surfactant, and the like.

Further, in the information recording medium of the present invention,
The thickness of the information recording layer needs to be applied accurately and uniformly. However, by forming the information recording layer by the above method, the uniformity of the film thickness is as follows when the film thickness is 5 μm to 10 μm. The surface roughness Ra can be set to 200 Å or less, the contrast is not uneven, and the shading phenomenon does not occur at the time of recording information.

Generally, in the case of this type of polymer-dispersed liquid crystal, it is considered that the resolution depends more on the domain size of the liquid crystal than on the film thickness, but the information recording of the present invention. When the resin has a large liquid crystal content such as a layer and the resin phase forms in a particle shape, the domain size of the liquid crystal is taken into consideration much like a polymer dispersed liquid crystal having a low normal liquid crystal content. Since there is no need, it is possible to easily provide an information recording medium with high sensitivity and high contrast ratio.

Since the information recording layer in the present invention can prevent the liquid crystal from seeping out from the surface of the information recording layer, the information recording layer can be free from noise due to the seeping of the liquid crystal, and can be kept in mutual time course. The influence can be prevented.

Next, an information recording method on the first information recording medium of the present invention will be described. The information is recorded using a method such as an optical sensor, heat, laser, corona charging, etc., but preferably, an optical sensor is used to record the information. As such an optical sensor, an electrode layer and a photoconductive layer are laminated on a transparent substrate.

As the transparent substrate, the plastic substrate in the information recording medium described above may be used, and when a photoconductive layer is formed by coating, a photosensor having smoothness can be used.

As the photoconductive layer, a single layer system having a charge generating function and a charge transporting function corresponding to information light at the same time, and a laminated system in which a charge generating layer and a charge transporting layer are sequentially laminated on an electrode layer And the same material and forming method as the photoconductive layer in the second information recording medium described later. The photoconductive layer generally has a function of generating photocarriers (electrons and holes) in the irradiated portion when irradiated with light, and these carriers can move in the layer width. When present, the effect is significant. Examples of such an optical sensor include the optical sensor described in Japanese Patent Application No. 4-287983. In the optical sensor described in this publication, the electric field or the amount of electric charge applied to the information recording medium at the time of light irradiation is amplified as the light is irradiated, and the conductivity of the sensor is maintained when the voltage is continuously applied even after the light irradiation is completed. It has a function of continuing and continuously applying an electric field or an electric charge to the information recording medium.

An information recording device incorporating an optical sensor is shown in FIG. In the figure, 1 is an optical sensor, 3 is an information recording medium, and 1
3, 13 'are electrode layers, 14 is a photoconductive layer, 11 is an information recording layer, 15 is a substrate, 19 is a spacer, 21 is a light source, 22
Is a shutter having a drive mechanism, 23 is a pulse generator (power supply), and 24 is a dark box.

First, a voltage is applied between the electrodes 13 and 13 'by a power source. When recording on the information recording medium, the information recording medium is heated by, for example, resistance heating (not shown) embedded in the support to heat the liquid crystal to a temperature at which the liquid crystal phase is exhibited. Can be improved.

When information light is made incident from the light source 21 while applying a voltage by the pulse generator 23 between the electrodes 13 and 13 ', photo carriers generated in the photoconductive layer 14 at the portion where the light is made incident are generated on both electrodes. By the electric field formed by, the electric field moves to the interface on the information recording layer side, the voltage is redistributed, the liquid crystal phase in the information recording layer is aligned, and recording is performed according to the pattern of the information light. In the figure, the photoconductor side is the positive electrode and the information recording medium side is the negative electrode, but it goes without saying that the polarity is set according to the discharge characteristics of the optical sensor.

When setting the applied voltage, since some liquid crystal materials operate at a low voltage, the voltage distributions of the optical sensor, the air gap, and the information recording medium are appropriately set and applied to the information recording layer. The voltage should be set in its operating voltage range. The information recording by this optical sensor can be made into a plane analog recording, and the orientation of the liquid crystal phase can be oriented at the electrostatic charge level to obtain the same high resolution as in the silver salt photography method. Is retained as a visible image due to the orientation of the liquid crystal phase.

As a method of inputting information to the first information recording medium of the present invention, there are a method using a camera and a recording method using a laser. As a method using a camera, an information recording medium is used instead of a photographic film used in a normal camera, and it is used as a recording member, and an optical shutter can be used and an electric shutter can also be used. It is profitable. Further, the optical information is separated into R, G, and B light components by a prism and a color filter, and taken out as parallel light to form one frame with three sets of R, G, B decomposed information recording media, or on one plane. Color images can also be taken by arranging the R, G, and B images side by side to form one frame for one set.

The laser recording method is as follows.
Argon laser (514.488n)
m), a helium-neon laser (633 nm), a semiconductor laser (780 nm, 810 nm, etc.) can be used,
Laser exposure corresponding to an image signal, a character signal, a code signal, and a line drawing signal is performed by scanning. An analog recording such as an image is performed by modulating the light intensity of the laser, and a digital recording such as a character, a code or a line drawing is performed by ON / OFF control of the laser light. In the case of halftone dot formation in an image, laser light is subjected to dot generator ON-OFF control.

As shown in FIG. 3, when the electrostatic information recorded on the information recording medium is reproduced by transmitted light, the liquid crystal is oriented in the electric field direction in the information recording portion, so that the light A is transmitted. On the other hand, the light B is scattered at the portion where no information is recorded, and the contrast with the information recording portion can be obtained.
The information recorded by the alignment of the liquid crystal is visible information that can be visually read by transmitted light, but it can also be magnified and read by a projector, and can be read by transmitted light using laser scanning or CCD. Therefore, information can be read with high accuracy, and scattered light can be prevented by using a Schlieren optical system as needed. Further, it can be read by reflected light. When contrast is a problem, it is advisable to provide a reflective layer on either layer.

Next, the second information recording medium of the present invention will be described. The second information recording medium is one in which a photoconductive layer is incorporated into the first information recording medium, and does not require an optical sensor or the like for recording information and can record information by itself. FIG. 1B is a diagram for schematically explaining the cross section, in which 3 is an information recording medium, 11 is an information recording layer, 13 and 13 'are electrode layers, 14 is a photoconductive layer,
Reference numeral 5 is a substrate.

Photoconductive layer 14 laminated on electrode 13 '
There are a single layer type and a laminated type in which a charge generation layer and a charge transport layer are laminated. The photoconductive layer generally has a function of generating photocarriers (electrons and holes) in the irradiated portion when irradiated with light, and these carriers can move in the layer width. When present, the effect of the layer is remarkable, but in particular, the electric field applied to the information recording layer during light irradiation to the photoconductive layer is amplified with light irradiation, and the voltage is applied even after the light irradiation is completed. It is preferable to have a function of continuing the application of the magnetic field to keep its conductivity and continuously applying the electric field to the information recording medium.

First, the single-layer photoconductive layer is formed of an inorganic photoconductive substance or an organic photoconductive substance. As the inorganic photoconductive substance, Se, Se-Te, ZnO, Ti
O _2, Si, CdS, and the like, a vapor deposition method, a sputtering method, the electrode layer by a CVD method or the like, 5 to 30 [mu] m, alone or mixed system, is laminated preferably in a thickness of 20 to 30 [mu] m. Further, the above-mentioned inorganic photoconductor as fine particles may be dispersed in an organic insulating resin such as a silicone resin, a polyester resin, a polycarbonate resin, a styrene-butadiene resin, a styrene resin, or a polyvinyl acetal resin to form a photoconductive layer, In this case, 0.1 to 10 parts by weight, preferably 1 to 5 parts by weight, of the photoconductive fine particles are dispersed in 1 part by weight of the resin.

The organic photoconductive substance includes a polymer photoconductive substance and a dispersion of a low molecular weight photoconductive substance in an insulating binder. As the polymer photoconductive substance, for example, polyvinylcarbazole (PVK), poly-N-ethylenically unsaturated group substitution containing allyl group or acryloxyalkyl group ethylenically unsaturated group instead of vinyl group in PVK There are carbazoles, poly-N-ethylenically unsaturated group-substituted phenothiazines such as poly-N-acrylphenothiazine and poly-N- (β-acryloxy) phenothiazine, and polyvinylpyrene. Above all, poly
N-ethylenically unsaturated group-substituted carbazoles, particularly polyvinylcarbazole, are preferably used.

Examples of the low molecular weight photoconductive substance include oxadiazoles substituted with an alkylaminophenyl group and the like, triphenylmethane derivatives, hydrazone derivatives, butadiene derivatives, stilbene derivatives and the like. 1 part by weight is 0.1 to 5 parts by weight, preferably 0.1 to 1 part by weight of an electrically insulating resin such as a silicone resin, a polyester resin, a polycarbonate resin, a styrene-butadiene copolymer resin, a styrene resin or a polyvinyl acetal resin. It may be dispersed in parts by weight to form a film-forming organic photoconductive substance. The film thickness of these organic photoconductive substances after drying is 5 to 30 μm, preferably 10 to 30 μm.
m on the electrode.

If desired, the organic photoconductive layer may contain a persistent conductivity imparting agent described in Japanese Patent Application No. 4-287983. The above-mentioned organic photoconductive layer itself has a persistent conductivity, and this persistent conductivity imparting agent is added for the purpose of enhancing the persistent conductivity in the above-mentioned organic photoconductive layer. The persistent conductivity imparting agent is 0.001 to 1 part by weight with respect to 1 part by weight of the organic photoconductive substance,
Preferably 0.001 to 0.1 part by weight is added. If the added amount of the persistent conductivity imparting agent exceeds 1 part by weight,
This is not preferable because the amplification function of the photoconductive layer is significantly reduced. In addition, some persistent conductivity imparting substances do not have a spectral sensitivity in visible light, and when utilizing optical information in the visible light region, an electron-accepting substance is added to increase sensitivity in the visible light region. A dye or the like can be further added. Examples of the electron accepting substance include nitro-substituted benzene, diano-substituted benzene, halogen-substituted benzene, quinones and trinitrofluorenone. Examples of the sensitizing dye include triphenylmethane dye, pyrylium salt dye and xanthene dye. Electron-accepting substances, sensitizing dyes, etc.
It is added in an amount of 0.001 to 1 part by weight, preferably 0.01 to 1 part by weight, relative to 1 part by weight of the organic photoconductive substance. At the same time, when the optical information is in the infrared region, it is advisable to add a pigment such as phthalocyanine or the like, a pyrrole-based dye, a cyanine-based dye or the like in the same amount, and vice versa. In this case, the purpose is achieved by adding the same amount of each wavelength absorbing substance.

Next, the laminated photoconductive layer is formed by sequentially laminating the charge generation layer and the charge transport layer on the electrode, and includes an inorganic material photoconductive layer and an organic material photoconductive layer. The charge generation layer in the inorganic system is formed by depositing Se—Te, Si doped with sulfur, oxygen, or the like on the electrode by a vapor deposition method, a sputtering method, a CVD method, or the like to have a thickness of 0.05 μm to 1 μm. Then, as a charge transport layer, Se, As is formed on the charge generation layer.
₂ Se ₃ , Si, Si doped with methane or the like may be similarly laminated to have a film thickness of 10 μm to 50 μm.

Next, the charge generating layer in the organic system comprises a charge generating substance and a binder, and the charge generating substance is
Fluorenone azo pigments, monoazo pigments, bisazo pigments, pyrrole pigments, azulenium salt pigments, phthalocyanine pigments, polycyclic aromatic pigments, pyrylium salt pigments, triazo pigments, squarylium salt pigments, perylene pigments , Antoanthrone pigments, cyanine pigments, polycyclic quinone pigments, imidazole pigments and the like, and specific examples thereof include the charge generating substances described in Japanese Patent Application No. 4-287983.

Examples of the binder include silicone resin, styrene-butadiene copolymer resin, epoxy resin, acrylic resin, saturated or unsaturated polyester resin, PMMA resin, vinyl chloride resin, vinyl acetate resin, vinyl chloride-vinyl acetate mixed resin and the like. For example, the charge generation material is formed by dispersing it in a binder. The charge generating agent is preferably a fluorenone azo pigment or a bisazo pigment, and the binder is preferably a polyester resin or a vinyl chloride-vinyl acetate mixed resin. It is desirable that the charge generating agent and the binder are used in a mixing ratio of 0.1 to 10 parts by weight, preferably 0.1 to 1 part by weight, relative to 1 part by weight of the charge generating agent. The charge generation layer has a thickness after drying of 0.01 to 1 μm, preferably 0.1 to 1 μm.
0.3 μm is preferable.

The charge transport layer comprises a charge transport material and a binder. The charge transport material is a material having a good transport property of the charge generated by the charge generation material, and for example, a hydrazone-based material,
Pyrazoline-based, PVK-based carbazole-based, oxazole-based, triazole-based, aromatic amine-based, amine-based, triphenylmethane-based, butadiene-based, stilbene-based, polycyclic aromatic compound-based, etc. It is necessary to. Preferred are butadiene-based and stilbene-based charge transfer agents, and specifically, Japanese Patent Application No. 4-
The charge transport material described in Japanese Patent No. 287983 can be used.

As the binder, the same binders as those mentioned above in the charge generating layer can be used, but polyvinyl acetal resin, styrene resin and styrene-butadiene copolymer resin are preferable. The binder is
It is desirable to use 0.1 to 10 parts by weight, preferably 0.1 to 1 part by weight, relative to 1 part by weight of the charge transport agent. The thickness of the charge transport layer after drying is 1 to 50 μm, preferably 10 to 30 μm.

Examples of combinations of these charge generating substances and charge transporting substances include combinations of fluorenone azo pigments (charge generating substances) and stilbene type charge transporting agents, bisazo type pigments (charge generating substances) and butadiene type, hydrazone type substances. The combination of the charge-transporting agents described above is preferable.

In addition, the persistent conductivity imparting agent and the electron acceptor described in the section of the single-layer photoconductive layer are added to the charge generation layer and the charge transport layer in the laminated photoconductive layer in the same proportions. However, it is preferably added to the charge generation layer.

When the single-layer photoconductive layer or laminated photoconductive layer is an organic photoconductive layer, dichloroethane, 1,1,2-trichloroethane, monochlorobenzene, tetrahydrofuran, cyclohexane, dioxane, 1 , 2,3-trichloropropane, ethyl cellosolve, 1,1,1, -trichloroethane, methyl ethyl ketone, chloroform, toluene and the like may be used as a coating solution. The coating method may be a blade coating method, a dipping method, a spinner. A coating method and the like can be mentioned.

The photoconductive layer may be provided on the electrode via the charge injection control layer. The charge injection control layer is provided as needed, and is provided to control the charge injection property from the electrode to the photoconductive layer and adjust the voltage substantially applied to the information recording medium. However, in the information recording medium of the present invention, it is necessary to set the sensitivity of the photoconductive layer in the operating voltage region of the liquid crystal in the information recording layer. That is, the difference (contrast potential) between the potential (bright potential) applied to the information recording layer in the exposed portion and the potential (dark potential) applied to the information recording layer in the unexposed portion is made large in the liquid crystal operating region. Because it is necessary.

Therefore, for example, the dark potential applied to the liquid crystal layer in the unexposed portion of the photoconductive layer needs to be set to about the operation start potential of the liquid crystal, and 10 ⁵ V / cm to 10 ⁵ V / cm to the bulk of the photoconductive layer.
10 ^-4 to 10 ^-8 A under an electric field of ⁶ V / cm
The conductivity is required to the extent that a dark current of / cm ² is generated, and the range of 10 ^-5 to 10 ^-6 A / cm ² is preferable.
In the photoconductive layer having a dark current of 10 ^-8 A / cm ² or less, the liquid crystal layer is not aligned even in the exposed state, and in the photoconductive layer having a dark current of 10 ^-4 A / cm ² or more, the voltage is applied even in the unexposed state. At the same time, a large amount of current flows, the liquid crystal in the information recording layer is not aligned, and even if it is exposed, the difference in its transmittance cannot be obtained. The charge injection control layer is appropriately provided in relation to the characteristics of such an information recording medium. When it is necessary to keep the dark potential in the photoconductive layer low, the charge injection control layer is a layer having a charge injection preventing property. There are two types of charge injection prevention layers, a layer utilizing a so-called tunneling effect and a layer utilizing a rectifying effect, and the one described in Japanese Patent Application No. 4-287983 can be used.

Next, the information recording layer 11 described in the section of the first information recording medium is sequentially laminated on the photoconductive layer 14 in the same manner as the first information recording medium.

In this second information recording medium, since the liquid crystal can be prevented from seeping out from the surface of the information recording layer, the electrode layer 13 is directly vapor-deposited on the surface of the information recording layer 11 by the sputtering method. It is possible to form the electrode layer 13 with no decrease in conductivity.

The electrode layer 13 can be the same as the electrode layer in the above-mentioned first information recording medium, but since a skin layer made of only resin is formed on the surface of the information recording layer, for example, an ITO film is vapor-deposited. Even if the film is laminated to a thickness of 1000 Å by a sputtering method or the like, no cracks or the like can be generated. One or both of the electrode layers 13 and 13 'may be transparent. The electrode 13 on the information recording layer
A substrate similar to the first information recording medium may be laminated on top.

Next, in this second information recording medium, a transparent insulating layer may be provided between the photoconductive layer 14 and the information recording layer 11. When the transparent insulating layer is provided, it is particularly suitable when the photoconductive layer is an organic photosensitive layer formed by using a solvent, and the liquid crystal in the information recording layer is eluted by the interaction between the photoconductive layer and the information recording layer. Alternatively, when the information recording layer is formed on the photoconductive layer by coating, the photoconductive material is eluted by the solvent for forming the information recording layer to prevent image unevenness.

Therefore, in forming the transparent insulating layer, it is necessary that it is incompatible with both the organic photoconductive layer forming material and the information recording layer forming material. Insulation is required because space charges diffuse and the resolution deteriorates. However, since the transparent insulating layer lowers the distribution voltage applied to the liquid crystal layer or deteriorates the resolution, it is preferable that the film thickness is thin, and the thickness is preferably 2 μm or less. In addition, the thinning causes not only the generation of image noise due to the interaction with time, but also the problem of penetration due to defects such as pinholes in the multilayer coating. Since the permeability varies depending on the solid content ratio of the material to be laminated and applied, the type of solvent, and the viscosity, the film thickness of the material to be laminated and applied is appropriately set. Further, in order to prevent these problems, the following materials may be laminated and used. Further, in consideration of the voltage distribution applied to each layer, it is preferable to use a material having a high dielectric constant as well as a thin film.

Such a transparent insulating layer is made of an inorganic material.
SiO ₂ , TiO ₂ , CeO ₂ , Al ₂ O ₃ , GeO ₂ , Si ₃ N ₄ , AlN, Ti
Alternatively, N ₂ , MgF ₂ , ZnS or the like may be used, and the layers may be laminated by a vapor deposition method, a sputtering method, a chemical vapor deposition (CVD) method, or the like. Further, an aqueous solution of polyvinyl alcohol, water-based polyurethane, water glass or the like may be used as a water-soluble resin having a low compatibility with an organic solvent, and the layers may be laminated by a spin coating method, a blade coating method, a roll coating method or the like. Further, a coatable fluororesin may be used, and in this case, it may be dissolved in a fluorine-based solvent and coated by a spin coating method, or laminated by a blade coating method, a roll coating method or the like. As the coatable fluorine resin, the fluorine resin described in Japanese Patent Application No. 4-24722 can be preferably used. When selecting a coating type transparent insulating material, the solvent does not dissolve the photoconductive layer, and does not dissolve in the material forming the information recording layer when forming the information recording layer by coating, or when coating. It is necessary that it does not dissolve in the solvent.

Further, in the case of an organic material which is formed into a film in a vacuum system, there is no fear of dissolving the photoconductive layer during the film formation. Of these, polyethylene, polypropylene, poly (monochlorotrifluoroethylene), polytetrafluoroethylene, etc. can be used as the material for forming the film by the vapor deposition method.
As a material for forming a film by the CVD method, polyparaxylene specifically described in Japanese Patent Application No. 4-24722 can be used. If the photoconductive layer is made of an inorganic material and there is no interaction such as liquid crystal seepage with the information recording layer, it is not necessary to provide the transparent insulating layer.

The transparent insulating layer is suitable for reproducing recorded information with transmitted light. However, when reproducing recorded information with reflected light, the transparent insulating layer is replaced with a dielectric material. It is advisable to stack mirror layers. As the dielectric mirror layer, for example, a layer in which a magnesium fluoride layer and a zinc sulfide layer are alternately laminated can be preferably used, and it has a high dielectric constant, which is preferable.

Next, an information recording / reproducing method for the second information recording medium of the present invention will be described. FIG. 4 is a diagram for explaining the information recording method. First, the electrode 1
A voltage is applied between 3 and 13 '. At the time of recording on this information recording medium, the information recording medium is heated by, for example, resistance heating (not shown) embedded in a support, and the liquid crystal is heated to a temperature showing a liquid crystal phase, thereby further improving the memory property. be able to.

While applying a voltage between the electrodes 13 and 13 ',
When the information light 18 is incident, the photocarriers generated in the photoconductive layer 14 at the portion where the light is incident move due to the electric field formed by the both electrodes, and the voltage is redistributed to thereby cause the liquid crystal phase in the information recording layer. Are aligned, and recording is performed according to the pattern of the information beam 18. The voltage may be applied for a predetermined time while the information light 18 is being incident.

Since some liquid crystals have different operating voltages and ranges, when setting the applied voltage and the applied voltage time, the voltage distribution in the information recording medium is appropriately set and the voltage distribution applied to the information recording layer is set to the liquid crystal. It is recommended to set it in the operating voltage range of.

This information recording method enables planar analog recording and obtains high resolution because recording can be performed at the liquid crystal particle level, and the exposure pattern is retained as a visible image due to the orientation of the liquid crystal phase. To be done.

As a method of inputting information to this information recording medium, the same method as the method using a camera and the method using a laser described in the section of the first information recording medium can be used. The recording method using a laser can be performed in the same manner, but the spectral characteristics of the photoconductive layer in this information recording medium do not need to be panchromatic and may be sensitive to the wavelength of the laser light source. . The information recorded on the second information recording medium is reproduced in the same manner as in the case of the first information recording medium shown in FIG.

Further, the first and second information recording media of the present invention are used by being cut in the layer width direction into an appropriate size according to the mode of use, and the information recording is made at the cut surface. The inside of the layer is exposed, and the liquid crystal phase exudes during storage. When this bleeding phenomenon occurs, a problem arises in that when information is recorded, accurate information cannot be recorded at the edge of the information recording medium. In order to prevent this, after cutting the information recording medium into an appropriate shape, a resin layer may be similarly laminated on the cut surface by the coating method or the laminating method to protect the cut surface. At the time of cutting, punching, CO ₂ laser processing, etc. can be carried out satisfactorily and without punching.

The first and second information recording media of the present invention record electrostatic information in a state where the electrostatic information is visualized by the orientation of the liquid crystal. However, by selecting the combination of the liquid crystal and the resin, Oriented and visualized information is not erased, and a memory property is provided. To erase the memory, it is preferable to heat it to a high temperature near the isotropic phase transition, and it can be used again for information recording.

[0090]

The first information recording medium of the present invention can be an information recording medium having smoothness without unevenness, warpage, etc., has a high electric resistance value, and scratches and the like occur on the back surface of the substrate. It can be used as an information recording medium having a high strength and excellent solvent resistance, and since the information recording layer can have a skin layer, the liquid crystal does not seep from the surface and there is no noise. It enables information recording with high sensitivity and high contrast.

In addition, since the second information recording medium has the photoconductive layer, it is not necessary to combine it with the optical sensor, and the information can be recorded by itself.
Further, since the liquid crystal bleeding phenomenon does not occur on the surface of the information recording layer, the electrode layer can be directly provided on the surface by the sputtering method or the like, and the conductivity is not deteriorated.
Further, in the information recording medium of the present invention, since the information recording layer can be uniformly thinned by the coating technique, a large area information recording medium can be manufactured, and a high resolution image can be recorded and reproduced. Hereinafter, examples will be described. In the examples, “parts” means parts by weight and “%” means% by weight.

[0092]

Example 1 Polyfunctional UV curable resin PPZ (Idemitsu Co., Ltd.)
5 parts and 0.1 part of the photoinitiator Darocur 1173 were mixed in methyl cellosolve so as to be 50%, and this solution was mixed with a 10 mm thick polymethylmethacrylate sheet (trade name S-0, Nitto resin ( Co., Ltd.) was coated on the entire surface by dip coating. After drying at 80 ° C for 30 minutes, irradiate with UV of 150mJ / cm ² and
An m-thick hard coat layer was obtained, and the plastic substrate in the present invention was produced.

This plastic substrate was immersed in chloroform and left for one day and night, but the substrate surface was not dissolved. Further, after the solvent was wiped off, a pencil hardness test under a load of 1000 g was carried out, and it had a hardness of 6H or more. The electric resistance was 2 × 10 ¹¹ Ω · cm at 25 ° C.

This plastic substrate was subjected to plasma CVD by a discharge power density of 0.5 W / cm ² and an argon gas flow rate of 0.2 cc / min. , 0.13 Torr, 100 J / c
Plasma processing was performed with energy of m ² . Then, an indium tin oxide (ITO) film with a film thickness of 1000 Å was formed on the plasma-treated surface by a sputtering method to obtain an electrode layer.

On the electrode, 40 parts of a polyfunctional monomer (dipentaerythritol hexaacrylate, manufactured by Toagosei Co., Ltd., M-400, molecular weight / functional group = 117), a photocuring initiator (2-hydroxy-2) -Methyl-1-phenylpropan-1-one, 2 parts by Ciba-Geigy: trade name Darocur 1173) -Smectic liquid crystal (BDH: S-6) 60 parts-Fluorine surfactant (Sumitomo 3M Co., Ltd .: 1 part of trade name Florard FC-430) was uniformly dissolved in 103 parts of xylene (manufactured by Junsei Kagaku Co., Ltd., reagent grade), and a solution was applied using a blade coater, and this was immediately applied at 47 ° C. for 3 days. After drying under reduced pressure for a minute, evacuation is performed, and after returning to normal pressure, 600 mJ / cm ²
Was irradiated with UV light to cure, and an information recording layer having a film thickness of 6 μm was laminated to manufacture an information recording medium of the present invention.

The obtained information recording medium had a smoothness of ± 0.01 mm per 10 cm ² and was excellent.

An ITO film having a film thickness of 500 Å was formed as an upper electrode on the obtained information recording layer by a sputtering method to form a good film. A lead wire was attached between both electrodes and a voltage of 500 V was applied to the terminal. When applied for 0.1 second, the transmittance of light with a wavelength of 600 nm was 4 before voltage application.
Although it was 0%, it was 80% after the voltage was applied, and there was some contrast. 2 in the information recording layer
The volume resistivity at 5 ° C. was 2 × 10 ¹¹ Ω · cm.

(Production of optical sensor) -The following structure as a charge generating agent

[0099]

[Chemical 1]

Using a mixed solvent of 3 parts of a fluorenone azo pigment (manufactured by Nippon Senshoku Co., Ltd.) having 1 part, a polyester resin (manufactured by Toyobo Co., Ltd., Byron 200), and 1,4-dioxane: cyclohexanone = 1: 1. A 100 g solution having a solid content of 2% was sufficiently dispersed with a paint shaker to prepare a coating solution, and a blade coater with a gap of 2 mil was used on the electrode layer side of the plastic substrate provided with the electrode layer prepared above. It was applied and dried at 100 ° C. for 1 hour to laminate a charge generation layer having a film thickness of 0.3 μm.

On the charge generation layer, the following structure was used as a charge transfer agent.

[0102]

[Chemical 2]

25 parts of para-dimethylstilbene, 5 parts of polystyrene resin (HRM-3 manufactured by Denka), 1,
1,2-trichloroethane 102 parts, dichloromethane 6
8 parts of the coating solution is applied using a blade coater, dried at 80 ° C. for 2 hours, and a charge transport layer is laminated to form a photoconductive layer having a thickness of 20 μm and including a charge generation layer and a charge transport layer. Layers were applied to obtain a light sensor.

Next, the obtained optical sensor and the information recording medium produced as described above are arranged so as to face each other with a PET film of 10 μm as a spacer, and are incorporated in the recording apparatus of FIG. The information recording medium side is negative,
A direct current voltage of 800 V was applied. With the voltage applied, exposure was performed from the photosensor side using a halogen lamp with an illuminance of 1000 lux as a light source for 0.1 seconds, and after the exposure was completed, the information recording medium was taken out and information recording was completed. The transmittance of the exposed portion was 80%, and the contrast ratio was excellent.

Further, an ordinary camera was used as an exposure method, and an object was photographed outdoors and in the daytime with a voltage of 700 V applied and an exposure f of 1.4 and a shutter speed of 1/60 seconds. When the information recording medium was taken out after the exposure, it was possible to see through an image having no noise and gradation. Further, as a result of reading this information recording medium with a scanner using a CCD line sensor and further outputting with a sublimation printer, a hard copy having gradation and high resolution was obtained.

[0106]

[Comparative Example 1] In Example 1, a polyfunctional UV-curable resin layer was coated on only one side of a polymethylmethacrylate sheet by a spin coating method and then treated in the same manner as in Example 1 to form a coating layer having a thickness of 5 μm. Provided, but 10c
A warp of 5 mm occurred in the plane of m ² .

An electrode layer and an information recording layer were laminated on this substrate in the same manner as in Example 1. However, the solvent used for forming the information recording layer was transferred to the back surface and the substrate was whitened.

Information was recorded by using an optical sensor as in Example 1, but the image fluctuated in the central part with the center as the boundary, and a shading phenomenon occurred. Further, the hardness of the polymethylmethacrylate sheet surface on the back surface of the information recording medium was HB, and scratches were generated during the work, and noise was generated as an image.

[0109]

Comparative Example 2 An information recording medium was prepared in the same manner as in Example 1 except that the polymethylmethacrylate sheet was not provided with the polyfunctional UV-curable resin layer.
A warp of 0.3 mm occurred in the plane of ² .

An electrode layer and an information recording layer were laminated on this substrate in the same manner as in Example 1. However, the solvent used for forming the information recording layer was transferred to the back surface and the substrate was whitened.

[0111]

Example 2 Fluorine-containing resin CYTOP (trade name; Asahi Glass) on the photoconductive layer of the optical sensor prepared in Example 1.
Co., Ltd., water absorption 0.01%, specific resistance 1 × 10 ¹⁸ Ω · c
m) perfluoro (2-butyltetrahydrofuran)
Dissolve in, and the 4.5% solution is 1500r with a spinner.
It was applied under the condition of pm for 20 seconds and dried at 80 ° C. for 1 hr to form a transparent insulating layer having a film thickness of 0.8 μm.

Then, an information recording layer having a thickness of 8 μm was formed on the transparent insulating layer as in Example 1, and an ITO film having a film thickness of 500 Å was formed as an upper electrode on the information recording layer by a sputtering method. Then, the second information recording medium of the present invention was produced.

This information recording medium was exposed by using a positive electrode for the photoconductive layer and a negative electrode for the information recording layer, applying a DC voltage of 700 V, and using a halogen lamp with an illuminance of 1000 lux as a light source from the photosensor side. After the exposure was completed for 0.1 seconds, the information recording medium was taken out and the information recording was completed.
The transmittance of 900 nm wavelength light in the unexposed area is 60.
%, And the transmittance in the exposed area is 80%,
The contrast was good.

As an exposure method, an ordinary camera was used, and an exposure using a halogen lamp with an illuminance of 2000 lux as a light source was exposed from the photoconductive layer side at a voltage application of 600 V. Exposure f = 1.4, shutter speed 1 The subject was photographed at / 60 seconds. After the exposure, the information recording medium was taken out, and it was found that an image having tone-free gradation was formed. Further, as a result of reading this medium with a scanner using a CCD line sensor and outputting with a sublimation printer, a hard copy having no noise, gradation and high resolution was obtained.

[Brief description of drawings]

FIG. 1 is a schematic view showing a cross section of an information recording medium of the present invention, where (a) shows a first information recording medium and (b) shows a second information recording medium.

FIG. 2 is a schematic diagram of an information recording device using an optical sensor.

FIG. 3 is a diagram for explaining a method of reproducing recorded information on an information recording medium.

FIG. 4 is a diagram for explaining an information recording method on a second information recording medium.

[Explanation of symbols]

1 is an optical sensor, 3 is an information recording medium, 11 is an information recording layer, 13 and 13 'are electrode layers, 14 is a photoconductive layer, 15 is a plastic sheet, 17 is a multifunctional ultraviolet curable resin layer, 1
Reference numeral 8 is information light, 19 is a spacer, 21 is a light source, 22 is a shutter having a driving mechanism, 23 is a pulse generator (power supply), 24 is a dark box, A is transmitted light, and B is scattered light.

Claims (3)

[Claims] 1. An information recording medium in which an information recording layer comprising an electrode layer, a liquid crystal phase and a resin phase is sequentially laminated on a plastic substrate, wherein the plastic substrate has a multifunctional ultraviolet curable resin on at least both front and back surfaces of the plastic sheet. An information recording medium having a coating layer composed of layers, and having an electrode laminated surface subjected to plasma treatment. 2. An information recording medium in which an electrode layer, a photoconductive layer, an information recording layer composed of a liquid crystal phase and a resin phase, and an electrode layer are sequentially laminated on a plastic substrate, wherein the plastic substrate is at least the front and back surfaces of the plastic sheet. An information recording medium having a coating layer composed of a polyfunctional UV-curable resin layer on both sides, and having its electrode laminated surface plasma-treated. 3. The information recording layer is applied with a mixed solution of a liquid crystal, a UV-curable resin forming material and a fluorine-based surfactant on the electrode layer and then cured by UV irradiation, and the outer surface thereof is UV-curable resin. The information recording medium according to claim 1 or 2, wherein the information recording medium is formed by being formed on a skin layer composed of only.