JPH0618917A - Information recording medium and method for recording and reproducing information - Google Patents

Abstract

PURPOSE:To provide an information recording medium preventing the exudation of a liq. crystal, improving the recordability of electrostatic information within a living temp. range and excellent in visualization and to provide a method for recording and reproducing information. CONSTITUTION:An information recording member 3 formed by successively laminating an information recording layer 11 and an electric charge retaining layer 14 on a transparent electrode 13 and a photosensitive member 1 formed by laminating a photoconductive layer 9 on a transparent electrode 7 are integrated with a gap in-between to obtain the objective information recording medium. The information recording layer 11 is a resin body contg. a dispersed and fixed liq. crystal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention records and stores electrostatic information as visible information using a resin body in which liquid crystal is dispersed and fixed,
The present invention relates to an information recording medium that can be reproduced at any time and an information recording / reproducing method thereof.

[0002]

2. Description of the Related Art Liquid crystal display devices have come to be used in displays for office automation equipment such as word processors and laptop computers. These are those in which a liquid crystal layer is sandwiched between transparent substrates such as glass or plastic substrates provided with a transparent electrode film, and information such as an image is displayed by applying a voltage between both electrodes using a single matrix or an active matrix. It is something to display.

As this system, a typical TN type, STN
In addition to the type, there are a dynamic scattering type that operates by current effect, a type that uses a cholesteric-nematic phase transition, and more recently, a type that combines a polymer and a liquid crystal. In a device in which a nematic liquid crystal is dispersed and fixed in a polymer resin body, by making the ordinary refractive index of the liquid crystal substance and the refractive index of the polymer resin substance match, a voltage is applied to align the liquid crystal substance in the direction of voltage application. When they are aligned, they become transparent, and when the voltage is not applied, the alignment of the liquid crystal substance becomes uneven, and as a result, they become opaque by scattering light at the interface between the liquid crystal and the polymer resin body or in the liquid crystal in which dispersion is fixed. This is used to display information in a transparent or opaque state.

A liquid crystal display device in which a nematic liquid crystal is dispersed and fixed in a polymer resin body can have a large area, a response time,
In particular, it has features such as a short rise time, high light utilization efficiency without the need for a polarizing plate, wide viewing angle, uniformness, and flexibility, and in recent years, it has been a window light control sheet or a projection display. It has been reported to be used. As a development for projection type displays or computer displays, the fall time is as short as 1-30 ms,
It has an advantage that the fall time is shorter than that of the TN type or STN type display which is most often used.

In a normal case, a liquid crystal display element in which a nematic liquid crystal is dispersed and fixed in a polymer resin body is one in which an alternating voltage is applied in a state of being sandwiched between electrodes, and display and erasing can be performed by turning the voltage on and off. Is. At this time, some hysteresis is generated in the voltage-to-light transmittance, and there is a report that there is a difference in the transmittance between when the applied AC voltage rises and when the applied AC voltage falls, but when the AC voltage is cut off, no voltage is applied. It returns to the initial transmittance, that is, the opaque state.

As a method of displaying information such as an image, a method of sandwiching it between matrix electrodes and turning it on and off for each pixel for display is generally used. When forming a composite film of molecules and a liquid crystal, for example, there is a method of irradiating image-like ultraviolet rays using a UV-curable polymer material, and all of them are for blinking fixed information.

On the other hand, as a memory device,
There is a method using cholesteric-nematic phase transfer, but in this method, it is necessary to have a sandwich structure in which a vertical alignment film is sandwiched between transparent electrodes formed on the electrodes. In this case, an electrode structure is required.

Recently, a liquid crystal cell has been developed which uses polymer dispersed liquid crystal instead of the liquid crystal layer. In such an information recording medium, a polymer-dispersed liquid crystal is held by being sandwiched between two substrates having ITO electrodes.

In addition, the information recording medium is provided with a substrate / ITO electrode /
The polymer-dispersed liquid crystal layer is formed, and when a voltage is applied in the state where it is opposed to the photoconductor consisting of the electrode and the photoconductive layer, a discharge phenomenon corresponding to the information light is caused to increase the electrostatic information. There is also developed a recording device in which the molecular dispersion type liquid crystal layer is aligned (Japanese Patent Laid-Open No. 2-186033).

However, this type of polymer-dispersed liquid crystal has a problem in that the phenomenon of liquid crystal bleeding on the surface of the information recording layer causes noise during information recording. In addition, an ITO electrode is directly laminated on the surface of the polymer-dispersed liquid crystal layer to form a substrate / ITO electrode / polymer-dispersed liquid crystal layer / I.
Some TO electrodes have a structure in which a voltage is applied between the two electrodes to orient the liquid crystal layer to record information, but the leaching of the liquid crystal also causes cracks, protrusions, etc. in the ITO electrode layer, resulting in electrical conductivity of the electrodes. There is a problem that the property deteriorates. Further, there is a problem of noise due to lamination, and the NI transition temperature of the liquid crystal is often 60 ° C. or lower, which causes a problem of memory property with respect to temperature.

[0011]

DISCLOSURE OF THE INVENTION The present invention has an improvement in memory property against liquid exudation or temperature of liquid crystal, which is a problem in an information recording medium using such a polymer-dispersed liquid crystal as an information recording layer. An object of the present invention is to provide an information recording medium and an information recording / reproducing method in which liquid crystal does not seep out, the recording property of electrostatic information in the living temperature range is improved, and the recorded information is excellent in visualization.

[0012]

The information recording medium of the present invention comprises an information recording member formed by sequentially laminating an information recording layer and a charge retention layer on a transparent electrode, and a photoconductive layer on the transparent electrode. An information recording medium in which the formed photoconductor member is integrated via a gap, wherein the information recording layer in the information recording medium is a resin body in which liquid crystals are dispersed and fixed.

Further, in the information recording / reproducing method of the present invention, an information recording layer made of a resin material in which liquid crystal is dispersed and fixed on a transparent electrode, an information recording member in which a charge retention layer is sequentially laminated, and a photoconductive layer on the transparent electrode. And are integrated with each other by facing a photosensitive member having a laminated structure with a gap therebetween, and an image is exposed while a voltage is applied to both electrodes, and an electrostatic latent image corresponding to the exposure pattern is recorded on the charge holding layer. It is characterized in that the liquid crystal is oriented, and then the exposure pattern recorded in the information recording layer in the orientation of the liquid crystal is reproduced as visible information by transmitting or reflecting light.

The information recording medium and the electrostatic information recording / reproducing method of the present invention will be described below. FIG. 1 is a sectional view of an information recording medium of the present invention, in which 1 is a photosensitive member, 5 is a transparent substrate, 7 is a transparent electrode, 9 is a photoconductive layer, 3 is an information recording member,
Reference numeral 11 is an information recording layer, 13 is a transparent electrode, 14 is a charge holding layer, and 15 is a transparent substrate.

The information recording layer 11 is formed by dispersing and fixing a low-molecular liquid crystal material in a resin body, and as the liquid crystal material, smectic liquid crystal, nematic liquid crystal, cholesteric liquid crystal or a mixture thereof can be used. ,
It is preferable to use the smectic liquid crystal from the viewpoint of the memory property, which retains the orientation of the liquid crystal and permanently retains information.

As the smectic liquid crystal, a cyanobisphenyl-based substance having a long carbon chain at a terminal group of a substance exhibiting liquid crystallinity,
Liquid crystal substances showing smectic A phase such as cyanoterphenyl type, phenyl ester type and fluorine type, liquid crystal substance showing smectic C phase used as ferroelectric liquid crystal, or liquid crystal showing smectic H, G, E, F, etc. Substances.

Alternatively, a nematic liquid crystal may be used,
For example, Schiff chlorine type, azoxy type, azo type, benzoic acid phenyl ester type, cyclohexyl acid phenyl ester type, biphenyl type, terphenyl type, phenyl cyclohexane type, phenyl pyridine type, phenyl oxazine type, polycyclic ethane type, phenyl cyclohexene type Well-known nematic liquid crystals such as cyclohexylpyrimidine, phenyl, and tolan can be used. Also, the memory property can be improved by mixing with a smectic or cholesteric liquid crystal. When selecting a liquid crystal material, a material having a large anisotropy in the refractive index is preferable because the contrast can be obtained.

As the resin body, a solvent-soluble type resin having compatibility with a solvent common to the liquid crystal material, such as an acrylic resin,
Methacrylic resin, polyester resin, polystyrene resin, and copolymers mainly containing them, or
UV or radiation curable resins, such as acrylic acid esters and methacrylic acid esters, which are compatible with the liquid crystal material in the monomer or oligomer state or compatible with a common solvent, and thermosetting resins, such as epoxy resin, Silicone resin etc. can be mentioned.

In particular, when an ultraviolet curable resin is used, a skin layer is formed on the surface of the information recording phase, and even if a large amount of liquid crystal is contained, phenomena such as liquid crystal seepage are suppressed, and the liquid crystal on the surface of the information recording layer is suppressed. It is possible to prevent the disturbance of the image due to the seepage and the decrease in the conductivity of the electrode layer. Examples of such an ultraviolet curable resin in a monomer or oligomer state include dipentaerythritol hexaacrylate, trimethylolpropane triacrylate, polyethylene glycol diacrylate, isocyanuric acid (ethylene oxide modified) triacrylate, and dipentaerythritol pentaacrylate. , Dipentaerythritol tetraacrylate, neopentyl glycol diacrylate, hexadiol diacrylate and other polyfunctional monomers or polyfunctional urethane-based, ester-based oligomers, nonylphenol-modified acrylate, N-vinyl-2-pyrrolidone, 2-hydroxy -3
And monofunctional monomers or oligomers such as phenoxypropyl acrylate.

The mixing ratio of 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 it is present, the transmittance is low even if the liquid crystal layer is oriented for information recording, and if it exceeds 90% by weight, phenomena such as seepage of liquid crystal occur, which is not preferable. The liquid crystal improves the contrast ratio by containing a large amount in the resin,
The operating voltage can be lowered.

The information recording member is prepared by laminating the information recording layer and the charge retention layer on the electrode 13 in this order. First, in the case of the solvent-soluble type, the resin body and the liquid crystal material are dissolved in the solvent. The solution is formed by coating the solution on the electrode with a general coater such as a blade coater, a roll coater, or a spin coater, and then removing the solvent. In the case of UV curable resin, after application,
It is formed by irradiating ultraviolet rays and curing. If necessary, a leveling agent may be added to improve coating suitability or improve surface properties. Further, by forming the information recording layer by the coating method, the film thickness of the information recording layer can be controlled uniformly. Although the film thickness affects the resolution, the film thickness after drying may be 0.1 μm to 10 μm, preferably 3 μm to 8 μm, whereby the operating voltage can be lowered while maintaining high resolution. .
If the film thickness is too thin, the contrast of the information recording portion will be low, and if it is too thick, the operating voltage will be high, such being undesirable.

The charge retention layer 14 is made of a highly insulating material for retaining the electric charge, which is electrostatic information, and is required to have an insulating property with a specific resistance of 10 ¹⁴ Ω / cm or more. Inorganic materials include SiO ₂ , CeO ₂ , Al
_{It is} advisable to use ₂ O ₃ , GeO ₂ , Si ₃ N ₄ , AlN, TiN, etc. and stack them by vapor deposition or sputtering. Alternatively, a water-soluble resin having a low compatibility with an organic solvent, such as polyvinyl alcohol, water-based polyurethane, or water glass, may be used and laminated with a blade coater, a roll coater, a spin coater, or the like. Furthermore, dissolve polytetrafluoroethylene, fluorinated ethylene propylene, tetrafluoroethylene perfluoroalkyl vinyl ether copolymer, polyimide resin, polyetherketone resin, polyvaraxylylene, etc. in a fluorine-based solvent and coat them for lamination. You can also

As described above, the charge retention layer is formed by vapor deposition, sputtering or the like, or by dissolving it in a solvent and coating it with a general coater such as a blade coater, a roll coater or a spin coater, and removing the solvent. However, a layer may be formed by adhering the above-mentioned polymer film through a laminate or an adhesive. The film thickness may be 1 μm to 40 μm.

Next, the photosensitive member 1 will be described. First, the photoconductive layer 9 is a layer in which photocarriers (electrons, holes) are generated in the irradiated portion when light is irradiated, and carriers from the photoconductive layer 9 can move in the layer width, and in particular, an electric field exists. In this case, the effect is remarkable. Hereinafter, a method for forming the photoconductive material and the photoconductive layer will be described.

(A) Amorphous silicon photoconductive layer includes (1) amorphous silicon simple substance, (2) impurity doped (B, Al, Ga, In, Tl, etc. by doping to P type (hole transport type). What you did
P, Ag, Sb, Bi, etc. are made 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 (10 ^-2 ~ 1 Torr), heated by glow discharge or deposited on an electrode substrate not heated to form a film, or simply thermochemically formed on a heated electrode substrate, or by vapor deposition or sputtering of a solid raw material A film is formed and used as a single layer or a laminated layer. The film thickness is 1 to 50 μm.

(B) Amorphous or crystalline selenium photoconductive layer includes (1) selenium alone, (2) selenium
There are (3) arsenic selenium compound (As ₂ Se ₃ ), (4) arsenic selenium compound + Te, etc., which are prepared by vapor deposition sputtering method. Also, combining these (1) to (4),
It may be a laminated photoconductive layer. The film thickness is similar to that of the silicon photoconductive layer.

The (C) cadmium sulfide (CdS) photoconductive layer is prepared by coating, vapor deposition and sputtering. In the case of vapor deposition, solid particles of CdS are placed on a tungsten board and vapor-deposited by resistance heating or EB (electron beam) vapor deposition. In the case of sputtering, a CdS target is used to deposit on a substrate in argon plasma. In this case, CdS is usually deposited in an amorphous state, but a crystalline alignment film (aligned in the film thickness direction) can be obtained by selecting the sputtering conditions. In the case of coating, it is advisable to disperse CdS particles (particle diameter 1 to 100 μm) in a binder, add a solvent, and coat the substrate.

The zinc oxide (ZnO) photoconductive layer (D) is formed by a coating method or a CVD method. The coating method can be obtained by dispersing ZnO particles (1 to 100 μm) in a binder, adding a solvent and coating the substrate. In addition, as the CVD method, an organic metal such as diethylzinc or dimethylzinc and oxygen gas are mixed in a low vacuum (10 ^{-2 to 1} Torr) and the electrode substrate (1) is heated.
(50 to 400 ° C.), and a zinc oxide film is deposited. Also in this case, a film oriented in the film thickness direction can be obtained.

The organic photoconductive layer (E) includes a single-layer type photoconductive layer and a function-separated type photoconductive layer. (A) The single-layer photoconductive layer is a mixture of the following charge generating substance and charge transporting substance, or a substance having both functions of charge generating and charge transporting, and charge transporting (CT) such as polyvinylcarbazole-trinitrofluorenone. ) Those having both functions by complex formation, or those having both functions by wavelength sensitization by a dye such as a mixture of polyvinylcarbazole and a basic dye.

<Charge Generating Substance> A substance which easily absorbs light to generate an electric charge. For example, azo pigments, disazo pigments, trisazo pigments, phthalocyanine pigments, perylene pigments, pyrylium dyes, cyanine dyes. , Methine dyes, triphenylmethane dyes, xanthene dyes and the like are used.

<Charge Transporting Material> A material having a good transporting property of one of the charges (mainly holes) that has been ionized, such as hydrazone type, pyrazoline type, polyvinylcarbazole type,
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 photosensitivity determined by the light absorption property of the charge generating substance, but when the above-mentioned system of the charge transport (CT) complex is described in detail, for example, polyvinylcarbazole (PVK) is sensed only in the ultraviolet region. No, trinitrofluorenone (TN
F) itself does not have the ability to generate electric charge, and has an absorption of 400 nm.
Although only near the wavelength, the PVK-TNF complex
Light absorption occurs up to a wavelength range of 650 nm, a photocharge generation function occurs in that region, and a function of transporting both charges (electrons and holes) is exhibited.

The film thickness of the single-layer photoconductive layer is 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. On the other hand, the charge-transporting substance has a good charge-transporting property but not a light-absorbing property. . Therefore, it is intended to separate the two and fully exert their respective characteristics.
It is a type in which a charge generation layer and a charge transport layer shown below are laminated.

<Charge Generating Substance> A substance which easily absorbs light to generate an electric charge, and is, for example, an azo pigment, a disazo pigment,
Trisazo pigments, phthalocyanine pigments, acidic xanthene dye pigments, cyanine dyes, styryl pigment pigments, pyrylium pigment pigments, perylene pigments, methine pigments, a-Se, aS
i, azurenium salt type, and squalium chlorine type.

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

As a method for producing the function-separated photoconductive layer,
First, a charge generating substance is applied onto an electrode together with a solvent and dried, then a charge transporting layer is applied onto the charge generating layer together with a solvent, and the dried charge generating layer is 0.1 to 10 μm. The film thickness may be 10 to 50 μm.

In any of the single-layer type and the function-separated type, as a binder, a vinyl chloride resin, a vinyl acetate resin, a vinyl chloride / acetate mixed resin, a silicone resin, a styrene resin, a styrene-butadiene copolymer resin is used. , Epoxy resin, acrylic resin, saturated or unsaturated polyester resin, polycarbonate resin, polyvinyl acetal resin, phenol resin,
A polymethylmethacrylate (PMMA) resin, a melamine resin, a polyimide resin or the like is added in an amount of 0.1 to 10 parts with respect to 1 part of each of the charge generating material and the charge transporting material to facilitate adhesion. As the coating method, a blade method, a spinner method, a gravure method, a dipping method, a vapor deposition method, a sputtering method or the like can be used.

Further, a charge transfer complex may be formed by forming a complex with a charge generating substance and a charge transporting substance.

Next, the photoconductive layer 9 is preferably laminated on the electrode 13 with a charge injection preventing layer interposed therebetween. The charge injection prevention layer is
It is provided in order to prevent dark current (charge injection from the electrode) when a voltage is applied, that is, a phenomenon in which charges move in the photosensitive layer as if they were exposed even though they were not exposed. There are two types of this charge injection prevention layer, a layer utilizing a so-called tunneling effect and a layer utilizing a rectifying effect.

Such a charge injection preventing layer is formed by a single layer such as an inorganic insulating film, an organic insulating polymer film, an insulating monomolecular film, or by laminating these layers. For example, 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, B
N, NbN, Si ₃ N ₄ , TaN, TiN, VN, ZrN, SiC, TiC
, WC, Al ₄ C _3, etc. are formed by glow discharge, vapor deposition, sputtering or the like. The film 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 the charge transporting layer having the charge transporting ability of the polarity opposite to that of the electrode substrate by utilizing the rectifying effect. The film thickness is 0.1-10
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 must be formed of a photoconductive material that generates carriers of the same polarity on the electrode side.

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

Next, the electrodes 7 and 13 of the information recording member and the photosensitive member will be described. The material of the electrode is not limited as long as the specific resistance value is 10 ⁶ Ω · cm or less, transparency is required, and metal thin film conductive film, inorganic metal oxide conductive film, organic conductive film such as quaternary ammonium salt, etc. may be used. is there. Such an electrode is formed on the support by a method such as vapor deposition, sputtering, CVD, coating, plating, dipping, and electrolytic polymerization. The film thickness needs to be changed depending on the electrical characteristics of the material forming the electrodes and the applied voltage at the time of recording information. For example, an ITO film has a thickness of 100 to 300.
It is about 0Å and is formed over the entire surface with the information recording layer or according to the formation pattern of the information recording layer.

The substrates 5 and 15 strongly support an information recording medium having a shape such as a card, a film, a tape, a disk, etc., and are required to have transparency, and the information recording layer is required to have a support property. If you have it, you don't need to provide it,
The material and thickness of the information recording layer are not particularly limited as long as they have a certain level of strength to support the information recording layer. For example, a flexible plastic film, or a rigid body such as glass, plastic sheet, or card is used. Specifically, when the information recording medium has a flexible film, tape, disk, or card shape, a flexible plastic film is used, and when strength is required, a rigid sheet, glass, etc. Inorganic materials and the like are used.

If necessary, a layer having an antireflection effect is laminated on the other surface of the substrate on which the electrodes are provided, or the transparent substrate is adjusted to a film thickness capable of exhibiting the antireflection effect. Alternatively, both may be combined to provide antireflection property.

Next, the photosensitive member 1 and the information recording member 3 produced as described above are integrated with each other through the spacer 2 as shown in FIG. The spacer 2 is formed on the information recording member or the photosensitive member, and is characterized in that a constant discharge gap can be obtained by stacking the photosensitive member and the information recording member. The spacer material may be an insulator, and for example, ink using a polymer compound as a binder may be used and integrally formed on the information recording member or the photosensitive member by a printing method or the like. Even if the spacer material contains a conductive substance, its resistance value is 1 when the ink after the layer formation is dried or cured.
It does not matter if it is 0 ⁶ Ω · cm or more. The ink composition may be appropriately set depending on the printing method, the material of the information recording portion and the photoconductor portion, and the thickness and area of the spacer. Further, the method of curing the ink after forming the layer can also be air-drying, heat-drying, UV-curing, EB-curing or the like according to the ink composition. Spacer members such as glass fine particles and plastic fine particles used in ordinary liquid crystal cells can be added to the spacer forming ink of the present invention to improve the spacer accuracy. When forming by the printing method, instead of patterning only the spacer portion, after uniformly coating the entire surface, a concave portion may be formed by etching or the like, and the peripheral portion thereof may be used as a spacer. The spacer may be formed by, for example, a laminating method, or by adhering a sheet or a film, in addition to the above-mentioned printing method, but the printing method is preferable because the film thickness is excellent.

Next, the information recording / reproducing method of the present invention will be described.

FIG. 2 is a diagram for explaining the method of recording information on the information recording medium of the present invention. As shown in FIG. 2A, the electrode 7 of the photosensitive member 1 and the electrode 1 of the information recording member 3 are shown.
3 is connected by a power source 17, and a voltage is applied between the electrodes 7 and 13 as shown in FIG. In a dark place, the photoconductive layer 9 is a high resistance material. In this state, when the information light 18 is made incident from the photoconductor 1 side, the photoconductive layer 9 at the portion where the light is made incident
Shows conductivity and becomes a low resistance body, information charges corresponding to incident light are discharged, and information charges are accumulated in the corresponding information recording layer. The information charges cause the liquid crystal to be aligned at the charge storage site. Even if there is a uniform fog charge in advance, the charge is further accumulated in the portion where the light is incident, so that information can be recorded by the contrast with the unexposed portion. Further, in FIG. 2, the information exposure is performed from the photoconductor side, but the information light may be incident from the information recording medium side, and the photoconductor side is the negative electrode,
Although the information recording medium side is shown as a positive electrode, it is needless to say that the polarity is set according to the discharge characteristics of the photoconductor.

When setting the applied voltage, since some liquid crystal materials operate at a low voltage, the voltage distribution of the photoconductor, the air gap, and the information recording medium is appropriately set and applied to the information recording layer. The voltage should be set in its operating voltage range.

The information recording method of the present invention is capable of planar analog recording and can obtain an alignment at the liquid crystal particle level, so that a high resolution can be obtained as in the silver salt photography method, and the exposure pattern is a liquid crystal phase. The orientation makes it visible and held.

As a method of inputting information to the information recording medium of the present invention, there are a high resolution electrostatic camera method and a laser recording method.

First, the high-resolution electrostatic camera uses the information recording medium of the present invention in place of the photographic film used in a normal camera, and a mechanical shutter for controlling the exposure amount can also be used. An electric shutter that controls the voltage application time can also be used. Also, 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 decompose into R, G, and B to form one frame with three sets of information recording media, or one plane. Color images can also be taken by arranging the R, G, and B images on top of each other and using a stripe color filter or the like to make one frame, and as a recording method using a laser, an argon laser (514.488n) is used as a light source.
m), a helium-neon laser (633 nm), a semiconductor laser (780 nm, 810 nm, etc.) can be used,
Information exposure is performed by scanning laser exposure corresponding to an image signal, a character progression, a code signal, a line drawing signal, a (0.1) signal, etc. in a state where a voltage is applied to the information recording medium of the present invention. An analog recording such as an image is performed by modulating the laser light intensity, and characters, codes, line drawings, (0.
Digital recording like 1) is performed by turning on the laser light.
Performed by OFF control. In addition, the dot generator ON-
It is formed by applying OFF control. In the case of laser exposure, the spectral characteristic of the photoconductive layer in the photoconductor does not have to be panchromatic, as long as it has sensitivity to the wavelength of the laser light source.

The information recorded by the orientation of the liquid crystal is visible information which can be visually read from the side of the information recording portion support, and can be magnified and read by a reflection type projector, and further laser light can be read. Scanning or C
Information can be read with high accuracy by reading with reflected light or transmitted light using a CD.

Regarding the orientation of the liquid crystal in the information recording layer, the visualized information is erased by heating it to a temperature in the vicinity of the isotropic phase transition of the liquid crystal. When the heating temperature is lower than the glass transition temperature of the polymer forming the charge retention layer, the information storage medium in which the alignment of the liquid crystal is erased is returned to room temperature, and is accumulated in the charge retention layer. The information charges cause the liquid crystal to be oriented again, and the visualized information appears. This is due to the electrostatic charge information held in the charge holding layer,
Because voltage is always applied to the liquid crystal of the information part,
By returning the temperature to room temperature, the liquid crystal is re-aligned and the electrostatic information is visualized again. Further, if the temperature of the charge retentive layer is maintained above the charge retentive temperature, that is, the glass transition temperature, the recorded information is completely erased and can be reused for information recording.

[0055]

In the information recording medium of the present invention, by forming a recording layer in which liquid crystal is dispersed in a polymer, it is possible to retain a low molecular weight liquid crystal and easily obtain an electro-optical effect. It can record and store analog information. In addition, since the information recording layer can be uniformly thinned by the coating technique, the gap between the information charges and the conductive layer can be made evenly small, a large area information recording medium can be manufactured, and a high-resolution image can be formed. It can be recorded and played back. In addition, it is opaque due to light scattering when it is not electrolyzed by information charges, and when electrolysis is applied, the liquid crystal phase is aligned, and by keeping the photorefractive index and the photorefractive index of the resin body almost the same, information recording The part can be made transparent, the deflecting plate is not required for reproducing information, and the optical system for reading can be simplified.

In the information recording medium of the present invention, by providing a charge retention layer on the surface of the information recording layer member, the orientation of the liquid crystal phase-the storability of visible information can be enhanced and the durability of information recording can be enhanced. You can In particular, the visible information due to the alignment difference of the liquid crystal is lost when the temperature exceeds the transition temperature of the liquid crystal,
The electrostatic information in the charge retention layer makes it visible again when the medium is left below the transition temperature. Further, by providing the charge retention layer, the retention of the information charge itself can be improved, and the electrostatic information can be reproduced electrically,
The information can be reproduced optically and electrically.

Further, in the information recording medium of the present invention, since the photoconductor member and the information recording member are integrally formed via the spacer, the charge holding layer holding the information charges is protected from moisture and the like. In addition, it is possible to store the information in contact with another information recording medium. Further, the strength of the information recording portion can be increased to the strength of breakage of the support. Further, by forming the spacer by the printing method, it is possible to improve the accuracy of the gap distance between the photoconductor member and the information recording member, and to obtain high sensitivity, high contrast, high quality,
It is possible to form a semi-permanent visible image.

The present invention will be described below with reference to examples. In addition, "part" shows a weight part.

[0059]

Example 1 (Production of Information Recording Member) Cyanobiphenyl Liquid Crystal (BD
H44 E44, Δn = 0.262, NI transition 100
0.2 g), PMMA (Mitsubishi Rayon Co., Ltd., B
R-80) 0.3 g was dissolved in 1,2-dichloroethane to prepare a 10 wt% solution, and this solution was sputtered onto a glass substrate having a thickness of 1 mm to form an indium tin oxide (ITO) electrode at 1000 Å. On a glass substrate electrode formed by laminating with a film thickness of
It was dried in an oven kept at ℃ for 1 hour to prepare an information recording medium of the present invention. The information recording layer is opaque white and has a thickness of 8
was μm.

Then, a 5% fluorine-based solution of a fluororesin (trade name: Cytop, manufactured by Asahi Glass Co., Ltd.) was applied onto the information recording layer by spin coating (1500 rpm; 30 seconds), and the solution was allowed to stand at room temperature for 1 day. After standing, it is dried in a vacuum oven at 80 ° C. to form a charge retention layer having a thickness of about 0.5 μm.
An information recording member was produced.

(Production of Photoreceptor Member) A solution in which 3 parts by weight of a bisazo pigment and 1 part by weight of a polyvinyl acetal resin as a charge generating material are adjusted to a solid content of 2% by weight with a mixed solvent of dioxane: cyclohexane = 1: 1. Was prepared, and this solution was formed by laminating indium tin oxide (ITO) electrodes with a thickness of 1000 Å on a glass substrate with a thickness of 1 mm by a sputtering method using a blade coater with a 2 mil gap. It was applied and dried at 100 ° C. for 1 hour to form a charge generation layer of 0.3 μm.

On the charge generation layer, p-diethylaminobenzaldehyde-N-phenyl- was used as a charge transport material.
15 parts of benzylhydrazone and 10 parts of a polycarbonate resin (trade name: Iupilon S-100 manufactured by Mitsubishi Gas Chemical Co., Inc.) were mixed with a mixed solvent of dichloromethane: 1,1,2-trichloroethane = 4: 6 to give a solid content of 17.8% by weight. The solution prepared as described above was applied with a blade coater having a thickness of 2 mil gap and dried at 80 ° C. for 2 hours to form a charge transport layer having a film thickness of 10 μm to obtain a photosensitive member.

(Preparation of Spacer) Dipentaerythritol hexaacrylate (DPHA, manufactured by Toa Kagaku: trade name Aronix 400) was mixed with 2% by weight of a photopolymerization initiator (Merck: trade name Darocur 1173) and printed. As an ink, a line pattern having a size of 5 cm × 5 cm and a width of 2 mm was printed using a 400 mesh screen printing plate on the charge transport layer of the photoreceptor member prepared above, and was cured by UV irradiation to a film thickness of about 10 μm. Spacers were formed.

Then, the information recording member produced above was
The charge retentive layer surface was overlaid on the spacer forming surface of the photosensitive member, and the support was fixed together with an adhesive tape to be integrated to prepare an information recording medium of the present invention. The gap between the information recording member and the photosensitive member was uniformly maintained at about 10 μm by the spacer.

(Information recording / reproducing method) As shown in FIG. 2, a voltage of 1000 V is applied to the information recording medium with the photoconductor side electrode being positive and the information recording member side electrode being negative. At the same time, optical information is transmitted from the photoconductor side. As a result of being applied for 0.1 sec, visible information was observed on the information recording layer.

The information recording medium on which information is recorded is
When left in an oven at 0 ° C. for 10 minutes, the information recording layer became transparent and the visible information was erased. When the information recording medium from which this visible information was erased was left at room temperature, the visible information was reproduced again. Also, similar results were obtained when recycled at an interval of 10 minutes between an oven at 100 ° C. and room temperature.

[0067]

Example 2 (Preparation of Information Recording Portion) Dipentaerythritol hexaacrylate 4 was used as an information recording layer of polymer dispersed liquid crystal.
Section, smectic liquid crystal (Merck: product name S6) 6
Part, fluorine-based surfactant (3M: trade name Florard F
C-430) 0.2 parts and a photopolymerization initiator (Merck & Co .: trade name Darocur 1173) 2 parts mixture were adjusted to a solid content of 30% by weight with xylene, and this solution was placed on a 1 mm thick glass substrate. Indium tin oxide (IT
O) An electrode was laminated on a glass substrate electrode having a film thickness of 1000 A to apply it with a blade coater, immediately maintain it at 50 ° C., and after 5 minutes, irradiate it with 0.3 J / cm ² of UV light. An information recording layer having a thickness of 6 μm was formed. The information recording layer was white and opaque.

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

Next, a charge retention layer having a film thickness of about 0.5 μm was formed on this information recording layer in the same manner as in Example 1 to prepare an information recording member.

As the photosensitive member, the photosensitive member manufactured in Example 1 was used. (Production of Spacer) Dipentaerythritol hexaacrylate (DPHA, manufactured by Toa Kagaku Co., Ltd .: trade name Aronix 400) is mixed with 2% of a curing agent (Merck Co .: trade name Darocur 1173) to prepare a spacer accuracy. For this purpose, 10 parts by weight of a rod having a length of φ10 μmm × 100 μm (manufactured by Nippon Electric Glass Co., Ltd .: trade name Micro Rod) was mixed, and 5 cm × 5 cm was used on the photoreceptor prepared in Example 1 using a 200 mesh screen printing plate. Width 2mm
Line pattern was printed.

Next, the information recording member produced above was placed on this line pattern, and the spacer material was cured by UV irradiation. As a result, the photosensitive member and the information recording member were bonded and integrated at the spacer portion. The gap between the photoconductor member and the information recording member was uniformly held at 10 μm.

(Information recording / reproducing method) As shown in FIG. 2, a voltage of 750 V is applied to the information recording medium with the photoconductor side electrode being positive and the information recording member side electrode being negative, and at the same time,
As a result of applying optical information for 0.1 sec from the photoreceptor side, visible information was observed in the information recording layer.

The information recording medium on which information is recorded is
When left in an oven at 0 ° C. for 10 minutes, the information recording layer became transparent and the visible information was erased. When the information recording medium from which this visible information was erased was left at room temperature, the visible information was reproduced again. Also, similar results were obtained when recycled at an interval of 10 minutes between an oven at 100 ° C. and room temperature.

[0074]

Example 3 The information recording member and the photoconductor member produced in Example 2 were integrated by a spacer as described below to produce an information recording medium.

(Production of Spacer) Dipentaerythritol hexaacrylate (DPHA, manufactured by Toa Kagaku Co., Ltd .: trade name Aronix 400) was mixed with 2% of a curing agent (Merck: trade name Darocur 1173), and further prepared.
Φ10μmm x 100μm for spacer precision
A long rod (manufactured by Nippon Electric Glass Co., Ltd .: trade name Microrod) is mixed in an amount of 10 parts by weight, and a charge-retaining layer surface of the information recording member is coated with a 200-mesh screen printing plate to obtain 5 cm ×.
A line pattern having a width of 5 cm and a width of 2 mm was printed, the above-mentioned photoreceptor members were superposed, and UV was irradiated from the information recording portion side to cure the spacer material. As a result, the photoconductor member and the information recording member were bonded and integrated by the spacer.

When electrostatic information was recorded on this information recording medium in the same manner as in Example 2, the same results as in Example 2 were obtained. Further, when a heating test was conducted in the same manner, similar results were obtained.

[Brief description of drawings]

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

FIG. 2 is a diagram for explaining an information recording / reproducing method of the present invention.

[Explanation of symbols]

1 is a photosensitive member, 5 is a transparent substrate, 7 is a transparent electrode, 9 is a photoconductive layer, 2 is a spacer, 3 is an information recording member, 11 is an information recording layer, 13 is a transparent electrode, 14 is a charge holding layer, 15 Is a transparent substrate

Claims (2)

[Claims] 1. An information recording member formed by sequentially laminating an information recording layer and a charge retention layer on a transparent electrode, and a photosensitive member formed by laminating a photoconductive layer on a transparent electrode are integrated with each other through a gap. An information recording medium, wherein the information recording layer in the information recording medium is a resin body in which liquid crystal is dispersed and fixed. 2. A gap between an information recording member in which an information recording layer made of a resin material in which liquid crystal is dispersed and fixed and a charge retention layer are sequentially laminated on a transparent electrode, and a photosensitive member in which a photoconductive layer is laminated on a transparent electrode. Are integrated by facing each other via, and imagewise exposure is performed with a voltage applied to both electrodes, an electrostatic latent image corresponding to the exposure pattern is recorded on the charge holding layer, and the liquid crystal is aligned,
Next, an information recording / reproducing method characterized in that an exposure pattern recorded in the information recording layer in the form of liquid crystal orientation is reproduced as visible information by transmitting or reflecting light.