JP3153344B2 - Information recording medium and electrostatic information recording / reproducing method - Google Patents

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 capable of obtaining, as visible information, electrostatic information recorded by an exposure recording method when a voltage is applied, and a method for recording and reproducing the electrostatic information.

[0002]

2. Description of the Related Art In the conventional electrophotographic technique, there is known an information recording medium in which a liquid crystal cell in which a nematic liquid crystal is sealed on a photoconductive layer and an insulating layer for liquid crystal alignment are sequentially laminated between a pair of electrodes. It is known that a liquid crystal is aligned by lowering the resistance of a photoconductive layer in an information exposure section by applying information while a voltage is applied between the electrodes, and obtaining a visible image using a deflecting plate.

This information recording medium needs to be formed into cells in order to enclose the liquid crystal. In addition, in order to perform twist nematic alignment at the initial stage, an insulating film in which both surfaces of the cells are subjected to an alignment treatment by rubbing treatment or the like is provided. In order to keep the gap constant, it is necessary to mix spacers, so that a high-resolution image cannot be obtained. In addition, there is an optical problem because a rigid and transparent support is required for producing a gap or a cell.
Further, there is a problem that the alignment treatment in the initial state cannot be detected unless a polarizing plate is used for reading.

On the other hand, recently, a liquid crystal layer in a liquid crystal cell has been developed by using a polymer-dispersed liquid crystal, and such a medium is held in a state sandwiched between two substrates having ITO electrodes. This medium is used as a substrate / ITO electrode /
When used in a method of recording electrostatic information on the liquid crystal layer by a discharge phenomenon corresponding to the information light by exposing at the time of voltage application in the state of facing the photoreceptor with a liquid crystal layer configuration, the polymer dispersion type There is a problem that the liquid crystal oozes out on the surface of the liquid crystal and causes noise when information is recorded. In addition, a voltage is applied between the two electrodes as a substrate / ITO electrode / liquid crystal layer / ITO electrode to align the liquid crystal layer. When the method is used for a method of recording information, the liquid crystal oozes out, causing a problem that the ITO electrode on the surface layer is cracked, embossed, etc., and the conductivity is reduced.

[0005]

The present invention relates to an improvement in an information recording medium using a polymer-dispersed liquid crystal as a liquid crystal layer, which can record electrostatic information with high accuracy and can easily reproduce information. It is an object to provide a simple information recording medium and a method for recording and reproducing electrostatic information.

[0006]

In the information recording medium of the present invention, a transparent electrode layer, an organic photoconductive layer, an information recording layer made of a resin in which a liquid crystal material is dispersed and fixed, and a transparent electrode layer are sequentially provided on a transparent substrate. An information recording medium, wherein a layer containing an inorganic charge transporting material is provided between the organic photoconductive layer and the information recording layer, and the resin body in the information recording layer is an ultraviolet curable resin; Polymerized and cured, forming the surface of the information recording layer as a skin layer consisting of only resin, and inside the information recording layer, a polymerized and cured transparent polymer was present in the liquid crystal material forming a continuous phase in the form of particles. I do.

Further, the method for recording and reproducing electrostatic information according to the present invention comprises:
A transparent electrode layer, an organic photoconductive layer, a layer containing an inorganic charge transporting material, an information recording layer composed of a resin body in which liquid crystal material is dispersed and fixed, and a transparent electrode layer are sequentially provided on a transparent substrate, and the resin body in the information recording layer is provided. Is an ultraviolet curable resin, the resin body is polymerized and cured, the surface of the information recording layer is formed as a skin layer made of only the resin, and a transparent polymer polymerized and cured in a liquid crystal material forming a continuous phase inside the information recording layer. Information is exposed while applying a voltage between both electrodes of the information recording medium in which particles exist in the form of particles to perform electrostatic information recording, and the recorded electrostatic information recording is reproduced as visible information by transmitted light or reflected light. It is characterized by doing.

Hereinafter, an information recording medium and an electrostatic information recording / reproducing method according to the present invention will be described.

FIG. 1 is a diagram schematically illustrating a cross section of an information recording medium of the present invention. In the drawing, 3 is an information recording medium, 11 is an information recording layer, 13 is a transparent electrode layer, and 14 is an organic recording medium. A photoconductive layer, 15 is a transparent substrate, and 16 is a layer containing an inorganic charge transport material.

The information recording layer 11 shown in FIG. 1 is formed by dispersing and fixing a low-molecular liquid crystal material in a resin body, and uses a smectic liquid crystal, a nematic liquid crystal, a cholesteric liquid crystal, or a mixture thereof as the liquid crystal material. However, it is preferable to use a smectic liquid crystal from the viewpoint of maintaining the orientation of the liquid crystal and maintaining the information permanently, that is, from the viewpoint of memory characteristics.

The smectic liquid crystal includes a liquid crystal material exhibiting a smectic A phase such as a cyanobiphenyl-based, cyanoterphenyl-based, phenylester-based, or fluorine-based one having a long carbon chain at the terminal group of a substance exhibiting liquid crystallinity. A liquid crystal material 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.

Also, a nematic liquid crystal may be used, and a memory property can be improved by mixing with a smectic or cholesteric liquid crystal. For example, Schiff base type, azoxy type, azo type, phenyl benzoate type, Cyclohexylic acid phenyl ester type, biphenyl type, terphenyl type, phenylcyclohexane type,
Known nematic liquid crystals such as phenylpyridine, phenyloxazine, polycyclic ethane, phenylcyclohexene, cyclohexylpyrimidine, phenyl and tolane can be used. When a liquid crystal material is selected, a material having a different direction of the refractive index is preferable because contrast can be obtained.

Examples of the resin body include a solvent-soluble resin having compatibility with a common solvent with the liquid crystal material, such as an acrylic resin, a methacrylic resin, a polyester resin, a polystyrene resin, and a copolymer mainly composed of these. Alternatively, a UV-curable resin having compatibility with a liquid crystal material in a state of a monomer or an oligomer or having compatibility with a common solvent, such as an acrylate ester and a methacrylate ester, and a thermosetting resin such as an epoxy resin and a silicone resin The use of an ultraviolet-curable resin, in particular, makes it possible to form the surface of the information recording layer on a skin layer composed of only the resin, even if a large amount of liquid crystal is contained, and the phenomenon of oozing out of the liquid crystal occurs. Suppressed, image unevenness due to seepage of liquid crystal onto the information recording layer surface, and cracks in the transparent electrode layer laminated on the information recording layer surface Generating decrease in conductivity can be prevented by such which are preferably used.

Such UV-curable resins include monomers and oligomers such as dipentaerythritol hexaacrylate, trimethylolpropane triacrylate, polyethylene glycol diacrylate, polypropylene glycol diacrylate, isocyanuric acid (modified with ethylene oxide). ) Multifunctional monomers such as triacrylate, dipentaerythritol pentaacrylate, dipentaerythritol tetraacrylate, neopentyl glycol diacrylate, hexanediol diacrylate, etc. or polyfunctional urethane and ester oligomers, and further nonylphenol-modified acrylates, N- Monofunctional monomers such as vinyl-2-pyrrolidone and 2-hydroxy-3-phenoxypropyl acrylate; Oligomer, and the like. By using a UV-curable resin to form a crosslinked structure, bleeding of liquid crystal can be prevented, and an ITO electrode can be directly provided by a sputtering method or the like. Further, a mixture obtained by mixing a polyvinyl alcohol or the like with a liquid crystal material to form a microcapsule can be used.

The mixing ratio between the liquid crystal material and the resin body is preferably such that the content of the liquid crystal material is 10% by weight to 90% by weight, preferably 40% by weight to 80% by weight. If there is, even if information is recorded and the liquid crystal phase is aligned, the transmittance is low, and if it exceeds 90% by weight, phenomena such as oozing of the liquid crystal occur, which is not preferable. By including a large amount of liquid crystal in the resin, the contrast ratio can be improved and the operating voltage can be reduced.

In the method of forming the information recording layer, in the case of a solvent-soluble type, a resin body and a liquid crystal material are dissolved in a solvent, and the solution is coated on a photoconductive layer or a transparent insulating layer described later by a blade coater or a roll coater. Alternatively, it is formed by coating with a general coater such as a spin coater and drying and removing the solvent. In the case of an ultraviolet curable resin, it is formed by further irradiating ultraviolet rays to cure. If necessary, a leveling agent may be added to improve the coating suitability or the surface property. Further, by forming the information recording layer by a coating method, the thickness of the information recording layer can be controlled uniformly. According to the laminating method, it is difficult to use a solvent and it is difficult to obtain uniformity of the gap. This is because it is necessary to pass through a spacer to make the uniformity, which causes noise.

The film thickness affects the resolution. When the film thickness after drying is 0.1 μm to 10 μm, preferably 3 μm to 8 μm, the operating voltage can be reduced while maintaining high resolution. If the film thickness is too thin, the contrast of the information recording portion is low, and if it is too thick, the operating voltage becomes high, which is not preferable. In the information recording layer, when the solvent is dried in the coating layer, the liquid crystal material undergoes phase separation with the solidification of the resin body,
The surface of the information recording layer is formed as a skin layer made of only a resin, and inside the information recording layer, a transparent polymer that has been polymerized and cured in a liquid crystal material forming a continuous phase is immobilized in a state of being present in the form of particles.

When the ultraviolet curable resin is cured by using ultraviolet rays, the characteristics of the information recording layer, such as the magnitude of the operating voltage range, the start of the reaction, etc., depend on the substrate temperature or the method of irradiating the ultraviolet rays, for example, intensity, amount, atmosphere, etc. Voltage, initial transmittance, etc. can be controlled.

Next, the organic photoconductive layer 14 will be described. The organic photoconductive layer is a conductive layer in which photocarriers (electrons and holes) are generated in the irradiated portion when light is irradiated, and the carriers can move in a layer width. In particular, an electric field exists. In this case, the effect is remarkable. Less than,
The method for forming the organic photoconductive material and the organic photoconductive layer will be described.

As the organic photoconductive layer, a single-layer type photoconductive layer,
There is a function separation type photoconductive layer. (A) The single-layer type photoconductive layer is a mixture of the following charge generating substance and charge transporting substance, or a substance having both functions of charge generation and charge transport, or a charge transport (CT) such as polyvinyl carbazole-trinitrofluorenone. ) Those having both functions by complex formation, or those having both functions by wavelength sensitization with a dye such as a mixture of polyvinyl carbazole and a basic dye.

<Charge-generating substance> A substance that easily absorbs light to generate an electric charge. Examples thereof include azo pigments, bisazo pigments, trisazo pigments, phthalocyanine pigments, perylene pigments, pyrylium dyes, and cyanine dyes. And methine dyes, triphenylmethane dyes, xanthene dyes, and the like.

<Charge transporting substance> A substance having good transport properties of one ionized charge (mainly holes), for example, hydrazone type, pyrazoline type, polyvinyl carbazole type,
There are carbazole type, stilbene type, anthracene type, naphthalene type, tridiphenylmethane type, butadiene type, azine type, amine type, aromatic amine type and the like. Usually, the photoconductive layer has photosensitive characteristics determined by the light absorption characteristics of the charge generating substance. However, when the above-described charge transport (CT) complex system is described in detail, for example, polyvinyl carbazole (PVK) is sensitive only in the ultraviolet region. , Trinitrofluorenone (TN
F) itself has no charge generating ability and has an absorption of 400 nm.
Although only near the wavelength, the PVK-TNF complex
Light absorption occurs up to the wavelength region of 650 nm, a photocharge generation function occurs in that region, and a function of transporting both charges (electrons and holes) is exhibited.

The single-layer photoconductive layer has a thickness of 10 to 50 μm.
Is preferred.

(B) Function-separated type photoconductive layer The charge-generating substance has a property of easily absorbing light but trapping light, while the charge-transporting substance has good charge-transporting properties but poor light-absorbing properties. . Therefore, the two are separated to try to fully exhibit their characteristics.
This is a type in which a charge generation layer and a charge transport layer shown below are laminated.

<Charge Generating Layer> Examples of the substance forming the charge generating layer include azo pigments, bisazo pigments, trisazo pigments, phthalocyanine pigments, acid xansen dyes, cyanine dyes, styryl dyes, and pyrylium dyes. System, perylene system, methine system, a-Se, a-Si, azurenium salt system, and squarium chloride system.

<Charge Transport Layer> Examples of the material forming the charge transport layer include hydrazone, pyrazoline, polyvinylcarbazole, carbazole, oxazole, triazole, butadiene, phenylmethane, azine, and amine. , Aromatic amines and polycyclic aromatic compounds.

The method for producing the function-separated type photoconductive layer is as follows.
First, the charge generation material is applied on the electrode together with the solvent and dried, and then the charge transport layer is applied on the charge generation layer together with the solvent, and the dried charge generation layer is 0.1 to 10 μm, and the charge transport layer is dried. The thickness is preferably 10 to 50 μm.

In either case of a single-layer type or a function-separated type, as a binder, a polyvinyl chloride resin, a vinyl acetate resin, a vinyl chloride mixed resin, a silicone resin, a styrene resin, a styrene-butadiene copolymer resin are used. , Epoxy resin, acrylic resin, saturated or unsaturated polyester resin, polycarbonate resin, polyvinyl acetal resin, phenolic resin,
A polymethyl methacrylate (PMMA) resin, a melamine resin, a polyimide resin, or the like is added in an amount of 0.1 to 10 parts to each one part of the charge generation material and the charge transport material so as to be easily attached. As the coating method, a blade method, a spinner method, a gravure method, a dipping method, an evaporation method, a sputtering method, or the like can be used.

Next, the organic photoconductive layer 14 may be laminated on the electrode 13 via a charge injection preventing layer. The charge injection preventing layer is provided to prevent a dark current when a voltage is applied (charge injection from an electrode), that is, a phenomenon in which charges are transferred in the photosensitive layer as if the light were exposed even though the light was not exposed. It is. The charge injection preventing layer includes two types, a layer using a so-called tunneling effect and a layer using a rectifying effect.

Such a charge injection preventing layer is formed of a single layer such as an inorganic insulating film, an organic insulating polymer film, an insulating monomolecular film or the like, or is formed by laminating them. As ₂ O ₃ , B ₂ O ₃ , Bi ₂ O ₃ , CdS, CaO, CeO ₂ ,
_{Cr 2 O 3, CoO, GeO} 2, HfO 2, Fe 2 O 3, La 2 O 3, MgO, Mn
_{O 2, Nd 2 O 3,} Nb 2 O 5, PbO, Sb 2 O 3, SiO 2, SeO 2, Ta 2 O
_{5, TiO 2, WO 3,} V 2 O 5, Y 2 O 5, Y 2 O 3, ZrO 2, BaTiO 3, Al
₂ O ₃ , Bi ₂ TiO ₅ , CaO-SrO, CaO-Y ₂ O ₃ , Cr-SiO, LiTa
_{O 3, PbTiO 3, PbZrO 3} , ZrO 2 -Co, ZrO 2 -SiO 2, AlN, BN,
_{NbN, Si 3 N 4, TaN} , TiN, VN, ZrN, SiC, TiC, W
C, Al ₄ C _{3 and the} like are formed by glow discharge, vapor deposition, sputtering and the like. The thickness of this layer is determined for each material used in consideration of the insulating property for preventing charge injection and the tunnel effect.

The charge injection preventing layer utilizing the rectifying effect is provided with a charge transporting layer having a charge transporting ability having a polarity opposite to the polarity of the electrode substrate utilizing the rectifying effect. The film thickness is 0.1 to 10
It is about μm. Specifically, when the electrode is negative, oxadiazole, pyrazoline, polyvinylcarbazole, stilbene, anthracene, naphthalene, tridiphenylmethane, triphenylmethane, azine, amine,
An organic photoconductive layer formed by dispersing an aromatic amine or the like in a resin is formed. These photoconductive layers need to be formed of a photoconductive material that generates carriers having the same polarity on the electrode side.

Depending on the characteristics of the photosensitive layer and the information recording layer, it may be preferable to increase the charge injection. In this case, the charge injection at the interface is increased by selecting the material of the electrode surface. You can also.

Next, the transparent electrode 13 will be described. The material of the transparent electrode is not limited as long as the specific resistance value is 10 ⁶ Ω · cm or less, and a metal thin film conductive film, an inorganic metal oxide conductive film,
Organic conductive films such as quaternary ammonium salts. Such an electrode is formed on a support by a method such as vapor deposition, sputtering, CVD, coating, plating, dipping, and electrolytic polymerization. The film thickness must be changed depending on the electric characteristics of the material constituting the electrode and the applied voltage at the time of recording information.
It is about 00 °, and is formed on the entire surface between the information recording layers or according to the formation pattern of the information recording layers.

The transparent substrate 15 strongly supports an information recording medium having a shape such as a card, a film, a tape, or a disk. It is not necessary to provide the transparent substrate 15 when the information recording layer has a supporting property. The material and thickness are not particularly limited as long as the material has a certain strength capable of supporting the information recording layer. For example, a rigid material such as a flexible plastic film or glass, a plastic sheet, or a card may be used. used. Specifically, when the information recording medium takes the form of a flexible film, tape, disk, or card, a flexible plastic film is used, and when strength is required, a rigid sheet, glass, or the like is used. Are used.

On the other side of the transparent substrate on which the transparent electrode is provided, a layer having an antireflection effect is laminated as necessary, or the transparent substrate is formed to a film thickness capable of exhibiting the antireflection effect. The antireflection property may be imparted by adjusting or further combining them. Further, in the information recording medium of the present invention, a transparent substrate or a transparent protective layer is laminated as necessary on the outermost transparent electrode layer, and contains a transparent substrate / transparent electrode layer / organic photoconductive layer / inorganic charge transport material. It is also possible to adopt a layer configuration of a layer to be formed / an information recording layer / transparent electrode layer / transparent substrate made of a resin body in which a liquid crystal phase is dispersed and fixed.

Next, the layer 16 containing the inorganic charge transporting material
Will be described. The layer containing the inorganic charge transport material,
The purpose is to prevent the liquid crystal in the information recording layer from being eluted by the interaction between the organic photoconductive layer and the information recording layer, and to prevent the solvent used in forming the information recording layer from eluting the photoconductive material to cause image unevenness. It is provided as. Therefore, the layer containing the inorganic charge transport material is an organic photoconductive layer forming material,
It is necessary that the material does not have compatibility with any of the information recording layer forming materials. In this regard, it is advantageous to use an inorganic charge transporting material. In the case of having conductivity, the space charge is diffused and the resolution is deteriorated, so that it is required to have a volume resistance of 10 ⁶ Ω · cm or more.

As the layer containing the inorganic charge transport material,
For example, an amorphous silicon layer, an amorphous or crystalline selenium layer, a cadmium sulfide (CdS) layer, a zinc oxide (ZnO) layer, and the like can be given.

First, as an amorphous silicon layer,
(1) Amorphous silicon alone, (2) P-type (hole transport type) by doping impurities (B, Al, Ga, In, Tl, etc.), P, Ag,
Sb, Bi, etc. are converted into N-type (electron transport type) by doping). As a forming method, silane gas and impurity gas are introduced into a low vacuum together with hydrogen gas or the like (10
^{-2 to 1} Torr), deposit by glow discharge to form a film,
It is formed simply by a thermochemical reaction or formed by depositing a solid raw material by vapor deposition and sputtering, and then forming a single layer or a laminated layer.

The amorphous or crystalline selenium layer includes (1) selenium alone, (2) selenium telluride, (3) arsenic selenium compound (As ₂ Se ₃ ), (4) arsenic selenium compound + Te, etc. Prepared by Also these
(1) to (4) may be combined to form a laminated charge transport layer.

The cadmium sulfide (CdS) layer is formed by coating, vapor deposition, and sputtering.
In the case of vapor deposition, solid particles of CdS are placed on a tungsten board and vapor deposition is performed by resistance heating or EB (electron beam) vapor deposition. In the case of the sputtering method, CdS
Deposition is performed in an argon plasma using a target.
In this case, CdS is usually deposited in an amorphous state, but a crystalline alignment film (oriented in the film thickness direction) can be obtained by selecting sputtering conditions. In the case of coating, CdS particles (particle diameter: 1 to 100 μm) may be dispersed in a binder, and a solvent may be added to coat on a substrate to form a film. .

The zinc oxide (Zn O) layer is formed by a coating method or a CVD method. As a coating method,
It is obtained by dispersing ZnO particles (particle diameter: 1 to 100 μm) in a binder, adding a solvent, and performing coating.
In the CVD method, an organic metal such as diethyl zinc or dimethyl zinc and oxygen gas are mixed in a low vacuum (10 ^{-2 to 1} Torr) and chemically reacted in a heated state to deposit a zinc oxide film. Also in this case, a film oriented in the film thickness direction can be obtained.

The layer containing the inorganic charge transporting material includes
An organic charge transporting material may be added to improve the charge transporting property.However, as the organic charge transporting material, the organic charge transporting material is dissolved in a solvent for dissolving an ultraviolet-curable resin used at the time of forming the information recording layer, It is necessary to select a material that does not cause image noise due to interaction with the recording layer over time.

The layer containing the inorganic charge transporting material may be formed by fixing and dispersing the inorganic charge transporting material in a resin, or by applying the inorganic charge transporting material by a vapor deposition method, a sputtering method, or the like.
Although formed by any one of the CVD methods, the layer containing the inorganic charge transporting material has a charge transporting property due to the inorganic charge transporting material. Such a distribution voltage is not significantly reduced. Therefore, the film thickness is preferably set to such a thickness that not only the occurrence of image noise due to the interaction with time but also the problem of permeation due to defects such as pinholes does not occur when laminating by the coating method. 1 μm to 1
It is good to set it between 0 μm.

The information recording medium of the present invention records electrostatic information in a state visualized by the orientation of liquid crystal.
In the information recording medium of the present invention, even if the electrostatic charge recorded on the resin body is removed, the information is once oriented, the visualized information is not erased, and a memory property is provided by selecting a combination with the resin body in the liquid crystal. Is done. Further, when heated to a high temperature near the isotropic phase transition, the memory is erased and can be reused for information recording.

The information recording medium according to the present invention has been described above. However, in the information recording medium according to the present invention, the bleeding of liquid crystal or the like can be prevented. Therefore, the information recording medium is formed of a substrate / ITO electrode / photoconductive layer / liquid crystal layer. May be used in a method of recording electrostatic information on a liquid crystal layer by a discharge phenomenon corresponding to information light by exposure at the time of applying a voltage in a state of facing an electrode.

Next, a method for recording and reproducing information on an information recording medium according to the present invention will be described.

FIG. 2A is a view for explaining a method of recording information on an information recording medium according to the present invention.

When the information light 18 enters from the information recording medium 3 side, the photocarriers generated in the photoconductive layer at the portion where the information is incident are moved by the electric field formed by both electrodes, and the voltage is redistributed. Thereby, the liquid crystal phase in the information recording layer is oriented.

Further, since the operating voltage and the range vary depending on the liquid crystal, the applied voltage and the applied voltage time are set by appropriately setting the voltage distribution between the electrodes and the information recording medium so as to cover the information recording layer. Preferably, the voltage distribution is set in the operating voltage range of the liquid crystal.

In this information recording method, planar analog recording is possible, and recording at the liquid crystal particle level is obtained, so that high resolution is obtained. Further, the exposure pattern is visualized and maintained by the orientation of the liquid crystal phase. Is done.

As a method for inputting information to the information recording medium of the present invention, there are a method using a camera and a method using a laser.

The camera is used in place of a photographic film used in a normal camera, and is used as a recording member. An optical shutter can be used, and an electric shutter can also be used. .

Further, optical information is separated into R, G, and B light components by a prism and a color filter, extracted as parallel light, and R, G, and B separated into three information recording media.
Color photography can also be performed by forming frames or by arranging R, G, and B images on one plane with a stripe filter or the like to make one frame in one set.

As a recording method using a laser, an argon laser (514.488 nm) is used as a light source,
A helium-neon laser (633 nm) and a semiconductor laser (780 nm, 810 nm, etc.) can be used, and laser exposure corresponding to an image signal, a character signal, a code signal, and a line drawing signal is performed by scanning. Analog recording such as an image is performed by modulating the light intensity of a laser, and digital recording such as characters, codes, and line drawings is performed by ON-OFF control of a laser beam. In the case where halftone dots are formed in an image, the laser light is formed by performing dot generator ON-OFF control. In the case of laser exposure, the spectral characteristics of the photoconductive layer in the information recording medium do not need to be panchromatic, but only need to have sensitivity to the wavelength of the laser light source.

As shown in FIG. 2B, when the electrostatic information recorded on the information recording medium is reproduced by the transmitted light, the light A is transmitted because the liquid crystal is oriented in the direction of the electric field in the information recording portion. On the other hand, the light B is scattered in a portion where information is not recorded, and a contrast with the information recording portion can be obtained. The information recorded by the orientation of the liquid crystal is visible information that can be visually read with transmitted light, but can also be read by enlarging with a projector, and is read with laser scanning or transmitted light using a CCD. Information can be read with high accuracy,
Scattered light can be prevented by using a schlieren optical system as needed.

Further, it can be read by reflected light. If contrast is a problem, a reflective layer may be provided on any of the layers.

[0057]

Since the information recording medium of the present invention is formed by using a recording layer in which a liquid crystal phase is dispersed in a resin body, the liquid crystal can be retained without forming cells, and the electro-optical effect can be easily obtained. Is obtained. In addition, the recorded information can be read by using the contrast between the scattered light and the transmitted light without using a polarizing plate, and the information recording layer can be uniformly thinned by the coating technology, so that the information recording layer gap can be reduced uniformly. Thus, a large-area information recording medium can be manufactured, and a high-resolution image can be recorded and reproduced.

That is, the information recording medium of the present invention is opaque due to light scattering in a state where no electric field is applied due to the generation of photocarriers of the photoreceptor by image information light, whereas the liquid crystal phase is changed when an electric field is applied. Orientation allows the information recording part to be in a transparent state, enables analog image recording by modulating an electric field, does not require a deflecting plate when reproducing information, and requires an optical system when reading information. It can be simplified.

In the information recording medium of the present invention, by providing a layer containing an inorganic charge transporting material between the organic photoconductive layer and the information recording layer, the interaction between the organic photoconductive layer and the information recording layer can be improved. It is possible to eliminate image unevenness and the like, and further, to suppress a decrease in distribution voltage applied to the information recording layer due to the provision of the isolation layer between the organic photoconductive layer and the information recording layer. Can be done.

Further, by using an ultraviolet curable resin as the resin in the information recording layer, the bleeding of the liquid crystal can be suppressed and more liquid crystal can be contained, so that the film thickness can be reduced. The voltage can be set low, and a high-sensitivity, high-contrast, high-quality visible image can be formed.

Hereinafter, the embodiment will be described.
"Parts" indicates parts by weight, and "%" indicates% by weight.

[0062]

Embodiment 1

[0063]

Embedded image

A 100 g solution of 3 parts of a bisazo pigment having the above-mentioned structure and 1 part of a polyvinyl acetal resin as a charge generating material having a solid content of 2% in a mixed solvent of dioxane: cyclohexane = 1: 1 was sufficiently dispersed by a ball mill. The solution was applied to the ITO surface side of a glass substrate having an ITO transparent electrode (film thickness: about 500 °, resistance value: 80Ω / port) with a blade coater having a gap of 2 mil, and
The resultant was dried at a temperature of 1 ° C. for 1 hour to form a charge generation layer having a thickness of 0.3 μm.

Next, 15 parts of p-diethylaminobenzaldehyde-N-phenyl-benzylhydrazone and 10 parts of a polycarbonate resin (Mitsubishi Gas Chemical: Iupilon S-100) were used as a charge transport material, and dichloromethane:
The solid content was adjusted to 17.8% with a mixed solvent of 1,1,2-trichloroethane = 4: 6, and the solution was applied on the charge generation layer with a blade coater having a gap gap of 2 mil,
After drying at 80 ° C. for 2 hours, a charge transport layer having a thickness of 10 μm was formed.

Subsequently, a layer containing an inorganic charge transporting material was formed on the charge transporting layer by the following procedure. 3. A fluorine-containing resin Cytop (trade name; manufactured by Asahi Glass Co., Ltd., water absorption 0.01%, specific resistance 1 × 10 ¹⁸ Ω · cm) is dissolved in perfluoro (2-butyltetrahydrofuran).
100 g of a 5% solution and 1 g of zinc oxide ultrafine particles (manufactured by Sumitomo Cement Co., Ltd.) were mixed, and sufficiently dispersed by a ball mill.
The coating was performed under the conditions of m and 20 seconds, dried at 80 ° C. for 3 hours, and a layer containing an inorganic charge transporting material having a thickness of about 1.4 μm was formed.

Further, on the layer containing the inorganic charge transporting material, 4 parts of dipentaerythritol hexaacrylate and 6 parts of smectic liquid crystal S6 (trade name; manufactured by Merck Ltd.) were formed as an information recording layer of polymer dispersed liquid crystal. , Fluorinated surfactant Florard FC-430 (trade name; manufactured by 3M)
0.2 parts, photopolymerization initiator Darocure 1173 (trade name,
(Merck Co., Ltd.) 0.2 parts of the mixture was mixed with xylene to obtain a solid content of 3
The solution was adjusted to 0%, and the solution was applied with a blade coater having a gap thickness of 50 μm.
Irradiated with UV light of / cm ^2, an information recording layer of a polymer dispersed liquid crystal having a thickness of about 6 μm was obtained.

After the liquid crystal was extracted from the section of the information recording layer with hot methanol and dried, the internal structure was observed with a scanning electron microscope (S-800, manufactured by Hitachi, Ltd., 10000 ×). However, the surface of the layer is covered with an ultraviolet curable resin having a thickness of 0.6 μm, and the inside of the layer has a particle size of 0.1 μm.
It was found to have a structure in which m resin particles were filled.

Further, ITO was laminated on this information recording layer by sputtering at a thickness of about 200 ° as a transparent electrode, thereby producing an information recording medium of the present invention.

At the same time that the gray scale is projected and exposed from the photoconductive layer side of the information recording medium, a DC voltage of 900 V is applied between the ITO electrodes for 0.1 second, with the photoconductive layer side being positive and the information recording layer side being negative. As a result, a transmission image corresponding to the gray scale was formed on the information recording layer, and an image capable of obtaining a sufficient contrast was confirmed by the transmitted light even on the low exposure side of the gray scale.

Further, the information recording medium was read by a scanner using a CCD line sensor and output by a sublimation printer. As a result, a high-resolution hard copy having gradation was obtained.

[0072]

Example 2 A charge generation layer and a charge transport layer were sequentially laminated in the same manner as in Example 1 on the ITO surface side of a glass substrate having an ITO transparent electrode (thickness: about 500 °, resistance value: 80Ω / port). .

Next, amorphous selenium having a thickness of 2 μm was deposited on the charge transport layer as a layer containing an inorganic charge transport material by EB evaporation.

Subsequently, on the layer containing the inorganic charge transporting material, an information recording layer composed of a polymer-dispersed liquid crystal and a transparent electrode layer were sequentially formed in the same manner as in Example 1, and the information recording medium of the present invention was prepared. Was prepared.

At the same time as the gray scale is projected and exposed from the photoconductive layer side of this information recording medium, a DC voltage of 800 V is applied between the ITO electrodes for 0.1 second, with the photoconductive layer side positive and the information recording layer side negative. As a result, a transmitted image corresponding to the gray scale was formed on the information recording layer, and an image in which a sufficient contrast was obtained even at the low exposure side of the gray scale by reading the transmitted image with infrared light could be confirmed by the transmitted light.

[0076]

Comparative Example A charge generation layer and a charge transport layer were sequentially laminated on a glass substrate having an ITO transparent electrode (thickness: about 500 °, resistance value: 80 Ω / port) in the same manner as in Example 1, A photoconductive layer was formed.

Next, on this photoconductive layer, a fluorine-containing resin Cytop (trade name, manufactured by Asahi Glass Co., Ltd., water absorption 0.01%,
A specific resistance of 1 × 10 ¹⁸ Ω · cm) was dissolved in perfluoro (2-butyltetrahydrofuran) to obtain a solution having a solid content of 6%. The solution was applied by a spin coat method under the conditions of 1000 rpm and 20 seconds, and 80 ° C. for 3 hours. After drying, a transparent insulating layer having a thickness of 1.4 μm was formed.

Subsequently, on this transparent insulating layer, an information recording layer made of polymer dispersed liquid crystal and a transparent conductive layer were sequentially formed in Example 1.
The information recording medium of the present invention was produced in the same manner as described above.

At the same time that the gray scale is projected and exposed from the photoconductive layer side of the information recording medium, the DC voltage is 1400 V
Was applied between the ITO electrodes for 0.1 second with the photoconductive layer side being positive and the information recording layer side being negative, whereby a transmission image corresponding to a gray scale was formed on the information recording layer. However, compared with the medium manufactured in Example 1, an image having a sufficient contrast was not obtained on the low exposure side of the gray scale.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of an information recording medium of the present invention.

FIG. 2 is a diagram for explaining information recording and reproduction on the information recording medium of the present invention.

[Explanation of symbols]

3 is an information recording medium, 11 is an information recording layer, 13 is a transparent electrode layer, 14 is an organic photoconductive layer, 15 is a transparent substrate, 16 is a layer containing an inorganic charge transporting material, 18 is pattern exposure, and A is transmitted light. , B is the scattered light

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-4-256928 (JP, A) JP-A-3-155525 (JP, A) JP-A-3-221919 (JP, A) JP-A-59-1985 128520 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) G02F 1/135 G02F 1/13 505 G02F 1/1333

Claims (4)

(57) [Claims] 1. An information recording medium comprising: a transparent electrode layer, an organic photoconductive layer, an information recording layer made of a resin body in which a liquid crystal material is dispersed and fixed on a transparent substrate, and a transparent electrode layer. Rutotomoni a layer containing an inorganic charge transport material between the layer and the information recording layer, the resin in the information recording layer material
Is an ultraviolet curable resin, the resin body is polymerized and cured,
Forming the surface of the information recording layer as a skin layer made of resin only
Polymerized in the liquid crystal material, which forms a continuous phase, inside the information recording layer.
An information recording medium, wherein a cured transparent polymer is present in the form of particles . 2. The layer containing an inorganic charge transporting material is a layer in which an inorganic charge transporting material is dispersed and fixed in a resin.
Information recording medium as described. 3. The information recording medium according to claim 1, wherein the layer containing the inorganic charge transporting material is formed by any one of a vapor deposition method, a sputtering method, and a CVD method. 4. A transparent electrode layer, an organic photoconductive layer, a layer containing an inorganic charge transporting material, an information recording layer made of a resin in which a liquid crystal material is dispersed and fixed, and a transparent electrode layer are sequentially provided on a transparent substrate. > only Rutotomoni, the resin body is an ultraviolet-curable in the information recording layer
A resin, the resin body being polymerized and cured to form a surface of the information recording layer.
Is formed as a skin layer made of only resin, and the information recording layer
The polymerized and cured transparent weight is contained in the liquid crystal material forming the continuous phase inside.
The electrostatic information recording is performed by exposing information while applying a voltage between the two electrodes of the information recording medium in which the coalesced particles are present, and the recorded electrostatic information recording is converted into visible information by transmitted light or reflected light. An electrostatic information recording / reproducing method characterized by reproducing.