JPH0470864A - Information recording medium and electrostatic information recording and reproducing method - Google Patents

Abstract

PURPOSE:To record electrostatic information with good sensitivity and facilitate information reproduction without using any liquid crystal cell by nearly equalizing the light refractive indexes of a resin body and a liquid crystal material to each other. CONSTITUTION:This medium 3 is formed by laminating an electrode layer 13, a photoconductive layer 14, and an information recording layer on a base 15 in order, an information recording layer is formed by dispersing and fixing a low-molecule liquid crystal material 12 in a resin body 11, and nematic liquid crystal, etc., is used as liquid crystal 12. Then the light refractive index of the resin body 11 is nearly equalized to that of the oriented liquid crystal and when the both are greatly different in refractive index, reflection and scattering are caused on the interface between the liquid crystal and resin body and no transparent state is obtained at a recording part. Further, when a dielectric mirror layer is provided between the layer 14 and a state recording layer, state recording performance can be improved more.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to an information recording medium that can obtain electrostatic information as visible information by an exposure recording method during voltage application using a counter electrode, and its electrostatic Concerning information record relocation methods.

[Prior Art] In conventional electrophotographic technology, there are known cells in which nematic liquid crystals are aligned on a photoconductive layer, and information recording media in which insulating layers for liquid crystal alignment are sequentially laminated. It is known that after uniformly corona charging the entire surface of the insulating layer for alignment, it is exposed to information to lower the resistance of the photoconductive layer in the information exposed area, aligning the liquid crystal, and using a polarizing plate to obtain a visible image. It is being

This information recording medium needs to be made into cells in order to encapsulate the liquid crystal, and in order to achieve twisted nematic orientation in the initial stage, an insulating film is provided on both sides of the cell that is oriented by rubbing, etc., and the cell gap is kept constant. It is necessary to mix spacers to keep it. In addition, since a rigid and transparent support is required to create gaps or cells in this way, the distance between the information charge applied to the surface of the information recording medium and the liquid crystal becomes longer, which increases the accuracy of information recording. The problem is that it gets worse.

On the other hand, the obtained visible image is read by transmitted light or reflected light, but when using transmitted light, if the light absorption of the photoconductive layer is large, the transmitted light becomes weak, so the light and absorption during information recording is In other words, methods such as lowering the sensitivity to light or recording using a wavelength different from that used for reading must be taken to increase the amount of transmitted light at the expense of performance. .

In addition, in the case of reflected light, the difference between the scattered light on the surface of the portion where the liquid crystal is not oriented and the reflected light from the interface between the photoconductive layer and the insulating layer for liquid crystal alignment can be read as contrast.

However, the photoconductive layer is light-absorbing;
Since the refractive index of the reflection from the interface of the insulating layer for liquid crystal alignment is almost the same, there is a problem that it cannot be read with sufficient contrast. On the other hand, the electrode layer of the information recording medium can be made light reflective, but in this case, the same problem as in the case of detection using transmitted light occurs in that the reflected light is absorbed by the photoconductive layer.

Furthermore, there is a problem in that objects that have been subjected to alignment treatment in their initial state cannot be detected without using a polarizing plate during reading. Since the image is uniformly charged by the corona charging process, the charging effect occurs even in the unexposed areas, which causes noise, and there is also the problem that a high-quality image cannot be obtained.

[Problem to be solved by the invention]

An object of the present invention is to provide an information recording medium and an electrostatic information recording/reproducing method that can record electrostatic information with high sensitivity without using a liquid crystal cell and that facilitates information reproduction.

[Means for Solving the Problems] The information recording medium of the present invention is an information recording medium in which a photoconductive layer and an information recording layer are sequentially provided on an electrode layer, and the information recording layer disperses and fixes a liquid crystal phase. The resin body is characterized in that the resin body and the liquid crystal material are selected so that their optical refractive indexes substantially match.

Further, in the electrostatic information recording and reproducing method of the present invention, the information recording layer is made of a resin body in which a liquid crystal phase is dispersed and fixed, and the information recording layer is selected such that the resin body and the liquid crystal substance have substantially the same optical refractive index. An information recording medium provided on an electrode layer via a conductive layer and a counter electrode are arranged, and electrostatic information is recorded by exposure while applying a voltage between both electrodes, and the electrostatic information recording is converted into visible information. It is characterized by being played as.

The information recording medium and electrostatic information recording/reproducing method of the present invention will be explained below.

FIG. 1 is a diagram for schematically explaining the cross section of the information recording medium of the present invention, in which (a) is a schematic diagram before information is recorded, and (b) is a diagram showing the state of reproduction of recorded information. A diagram to explain,
The same figure (C) is a figure showing other examples of the information recording medium of the present invention, and in the figure, 3 is an information recording medium, 11 is a resin body, 12 is a liquid crystal phase, 13 is an electrode layer, and 14 is a photoconductive layer. , 15 is a support,
16 is a dielectric mirror layer, and 17 is a charge retention layer.

As shown in FIG. 1(a), the information recording layer has a low-molecular liquid crystal material 12 dispersed and fixed in a resin body Il, and the liquid crystal material may be nematic liquid crystal, smectic liquid crystal, cholesteric liquid crystal, or any of these. A mixture of can be used.

For example, the following nematic materials can be used.

(Left below) Ship bases, e.g. azoxy-based, e.g. azo-based, e.g. benzoic acid phenyl ester-based, e.g./chlorhexylic acid phenyl ester L, e.g. Phenyl series, such as phenylchlorhexane series, e.g. phenylbilinone series, such as phenylnooxane series, such as phenyl series, etc. Also, tolan series, such as (wherein R, R' represent an aliphatic hydrocarbon) -Z N O -Z (In the formula, R represents an aliphatic hydrocarbon, Z represents a benzene ring, a cyclohexane ring, or a six-membered petroleum ring.) Also, these nematic liquid crystals can be mixed with smectic or cholesteric liquid crystals. This can improve memory performance. Note that when selecting a liquid crystal material, a material with a large anisotropy of refractive index is preferable because it provides better contrast.

The resin body may be a solvent-soluble resin that is compatible with the same solvent as the liquid crystal material, such as methacrylic resin, polyester resin, polystyrene resin, or a copolymer based on these, or a monomer or oligomer. It is possible to use radiation-curable resins that are compatible with the liquid crystal material, such as acrylic esters and methacrylic esters, as well as thermosetting resins, such as epoxy resins and silicone resins. Additionally, a mixture of polyvinyl alcohol and a liquid crystal material and microcapsules may also be used.

In addition, the information recording layer must be selected so that the optical refractive index of the resin body and the optical refractive index of the oriented liquid crystal are approximately equal, and if the refractive index of the two is significantly different, the liquid crystal and the resin body must Reflection and scattering occur at the interface, making it impossible to obtain a transparent state in the recording area.

The mixing ratio of the liquid crystal material and the resin body is such that the content of the liquid crystal material is 1
It is best to blend the liquid crystal in an amount of 0% to 80% by weight, preferably 30% to 60% by weight; if it is less than 10% by weight, even if information is recorded and the liquid crystal phase is oriented, the transparency will be low, and If it exceeds 80% by weight, phenomena such as bleeding of liquid crystals may occur, which is not preferable.

In the case of a solvent-soluble type green layer, the resin body and liquid crystal material are dissolved in a solvent, and the solution is applied onto the photoconductive layer or dielectric mirror layer using 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, but when the solvent is dried, the liquid crystal material undergoes phase separation as the resin body solidifies, resulting in a particle size of about 0.1 μm. It is thought that it is dispersed and fixed as a liquid crystal phase. Film thickness after drying is 01μm
It is preferable to set the thickness to 10 μm.

In addition, when using a solvent-soluble type or a thermosetting type as the resin body, the orientation of the liquid crystal material becomes random.
It is necessary to heat the material below the temperature at which it transitions to a so-called isotropic phase.

If the resin is dried and solidified in a state that has transitioned to an isotropic phase, liquid crystallinity will not be obtained and the electro-optical effect will not be exhibited.

The photoconductive layer 14 is a conductive layer in which photocarriers (electrons, holes) are generated in the irradiated area when light is irradiated, and these carriers can move across the layer width, especially when an electric field is present. This is the layer where the effect is noticeable in some cases. A photoconductive material and a method for forming a photoconductive layer will be described.

■) Silicon photoconductive layer ■Simple silicon■Doped with impurities, ・P by doping B5Al, Ga, In, TI, etc.
molded (hole transport type), ・P, Ag, Sb, B
There is a type in which i, etc. is made N type (electron transport type) by doping.

The method for forming the photoconductive layer is to introduce silane gas, impurity gas, etc. into a low vacuum together with hydrogen gas, etc.
Torr), heated by glow discharge or deposited on an unheated electrode substrate, formed by a thermochemical reaction on a heated electrode substrate, or formed by vapor deposition of a solid raw material or sputtering method. It can be used in single layer or laminated form. The film thickness is 1 to 50 μm.

(II) Selenium photoconductive layer ■Selenium alone ■Selene tellurium ■Arsenic selenium compound (As2Se3) ■Arsenic selenium compound + Te There is.

This photoconductive layer is produced by vapor deposition or sputtering. Moreover, a laminated photoconductive layer may be formed by combining the above items (1) to (2). The film thickness is similar to that of the silicon photoconductive layer.

(I) Cadmium sulfide (CdS 2 ) photoconductive layer This photoconductive layer is prepared by coating, vapor deposition, or sputtering methods. In the case of vapor deposition, CdS solid particles are placed on a tungsten board and vapor deposition is performed by resistance heating or by EB (electron beam) vapor deposition. In the case of sputtering, a CdS target is used to deposit on the substrate in argon plasma. In this case, CdS is usually deposited in an amorphous state, but a crystalline oriented film (oriented in the film thickness direction) can also be obtained by selecting sputtering conditions. For coating, CdS particles (
It is preferable to disperse particles (particle size: 1 to 100 μm) in a binder, add a solvent, and coat on a substrate. .

(IV) Zinc oxide (Zn 2 O) photoconductive layer This photoconductive layer is produced by a coating method or a CVD method. As a coating method, ZnS particles (particle size 1 to 100 μm)
is obtained by dispersing it in a binder, adding a solvent, and coating it on a substrate. Also, as a CVD method,
Organic metals such as diethylzinc and dimethylzinc are mixed with oxygen gas in a low vacuum (10-' to I Torr), and a chemical reaction is caused on a heated electrode substrate (150-400℃) to deposit a zinc oxide film. . In this case as well, a film oriented in the film thickness direction can be obtained.

(V) Leading conductive layer Organic photoconductive layers include single-layer photoconductive layers and functionally separated photoconductive layers.

(a) Single-layer photoconductive layer The single-layer photoconductive layer is made of a mixture of the following charge-generating substance and charge-transporting substance.

Charge-generating substances〉 Substances that easily generate charges by absorbing light, such as azo pigments, disazo pigments, trisazo pigments, phthalocyanine pigments, perylene pigments, pyrylium dyes, cyanine dyes, and methine dyes. dyes are used.

(Charge transport material system) A material with good transport properties for ionized charges, such as hydrazone type, pyrazoline type, polyvinylcarbazole type,
There are carbazole-based, stilbene-based, anthracene-based, naphthalene-based, tridiphenylmethane-based, azine-based, amine-based, aromatic amine-based, etc.

Alternatively, a charge-transfer complex may be obtained by forming a complex with a charge-generating substance and a charge-transporting substance.

Normally, a photoconductive layer has photosensitivity determined by the light absorption properties of a charge generating substance, but when a charge generating substance and a charge transporting substance are mixed to form a complex, the light absorption properties change; for example, polyvinylcarbazole (PVK) It is only felt in the ultraviolet region,
Trinitrofluorenone (TN F ) is 400 n
Although it is only felt near the m wavelength, the PVK-TNF complex has a wavelength of 65
You will be able to feel up to the 0nm wavelength range.

The thickness of such a single-layer photoconductive layer is preferably 10 to 50 μm.

(b) Functionally separated photoconductive layer A charge generating material easily absorbs light but has the property of trapping light, while a charge transporting material has good charge transport properties but poor light absorption properties. Therefore, it is an attempt to separate the two and make full use of their respective characteristics.
This is a type in which a charge generation layer and a charge transport layer are laminated.

<Charge generation layer> Examples of substances forming the charge generation layer include azo, bisazo, trisazo, phthalocyanine, acidic xanthene dye, cyanine, styryl dye, biryllium dye, perylene, methine, a-3e 5a-Si
, azulenium salt systems, squalium ring systems, etc.

<Charge Transport Layer> Examples of substances forming the charge transport layer include hydrazone, pyrazoline, PVK, carbazole, oxazole, triazole, aromatic amine, amine, triphenylmethane, and polycyclic aromatic materials. There are group compounds, etc.

The method for producing a functionally separated photoconductive layer is to first dissolve a charge generating substance in a solvent and apply it on the electrode, then dissolve the charge transport layer in a solvent and apply it to the charge transport layer, and then remove the charge generating layer from zero. .1 to 10 μm The thickness of the charge transport layer is preferably 10 to 50 μm.

In addition, in both single-layer and functionally separated types, silicone resins, styrene-butadiene copolymer resins, epoxy resins, acrylic resins, saturated or unsaturated polyester resins, polycarbonate resins, polyvinyl acetal resins, phenol are used as binders. resin, polymethyl methacrylate (PMMA) resin, melamine resin, polyimide resin, etc. for each part of the charge-generating material and the charge-generating material.
Add 0.1 to 10 parts to make it easier to adhere. As the coating method, a dipping method, a vapor deposition method, a sputtering method, etc. can be used.

Such a photoconductive layer 14 may be laminated on the electrode 13 with a charge injection prevention layer interposed therebetween.

The charge injection prevention layer is provided to prevent dark current (charge injection from the electrode) when a voltage is applied, that is, a phenomenon in which charges move through the photosensitive layer as if it were exposed even though it was not exposed. It is.

There are two types of charge injection prevention layers: a layer that utilizes a so-called tunneling effect and a layer that utilizes a rectification effect.

Such a charge injection prevention layer is formed of a single layer such as an inorganic insulating film, an organic insulating polymer film, an insulating monomolecular film, or a stack of these.
203, LL, B12O3, CdS.

CaO, CeL, CraO+, Coo, GeO
2, H[03, Fezes, La2es, MgO, M
nL, Nd2O3, Nb2O5, PbO.

5b2L, 5i02.5eOa, Ta2's, Ti
Di,WO3,v,05,Y2[1,,,Y,03,l
rL, BaTi0. ,,^1203 ,B12TIO5
, [:aO-3rO, Can-Y2O3, Cr-3in
, LiTaO3, PbTi0. , Pb2r[la, 7.
rDa-Co, 7rOz-3+Oz, AIN,
BNSNbN, SiJ, , TaN, TiN,
VN, Zr1i, SiC, TiC.

Red, ^1=c3, etc. are formed by glow discharge, vapor deposition, sputtering, etc. The thickness of this layer is determined depending on the material used, taking into account insulating properties to prevent charge injection and tunneling effects.

Next, the charge injection prevention layer utilizing a rectification effect is provided with a charge transport layer having a charge transport ability having a polarity opposite to that of the electrode substrate using a rectification effect. That is, such a charge injection prevention layer is formed of an inorganic photoconductive layer, an organic photoconductive layer, and an organic-inorganic composite photoconductive layer, and has a thickness of about 0.1 to 10 μm. Specifically, if the electrode is negative, B, AI,
Amorphous silicon photoconductive layer doped with Ga, 1N, etc., amorphous selenium, or oxadiazole, pyrazoline, polyvinylcarbazolone, anthracene, naphthalene, tridiphenylmethane, triphenylmethane, azine, amine, aromatic amine, etc. in the resin. When the organic photoconductive layer formed by dispersion and the electrode is positive, P
,N. An amorphous silicon photoconductive layer doped with As, Sb, Bi, etc., a ZnO photoconductive layer, etc. are formed by methods such as glow discharge, vapor deposition, sputtering, CVD, and coating. These photoconductive layers must be formed of a photoconductive material that generates carriers with the same polarity on the electrode side. If the electrode is negative, use B, AI
If the electrode is positive, the silicon photoconductive layer doped with P, N, As, Sb, Bi, etc., the selenium photoconductive layer, the organic photoconductive layer, etc. It is formed by a method such as discharge, vapor deposition, sputtering, CVD, or coating.

Next, the material of the electrode layer 13 is not limited as long as it has a specific resistance value of less than 10<6 >[Omega]. It may be a metal conductive film, an inorganic metal oxide conductive film, an organic conductive film such as a quaternary ammonium salt, or the like. Such electrodes can be deposited on a support by vapor deposition, sputtering, CV
D. Formed by methods such as coating, plating, dipping, and electrolytic polymerization. In addition, the film thickness needs to be changed depending on the electrical properties of the material constituting the electrode and the applied voltage during information recording; for example, in the case of an ITO film,
~3000 people, and is formed on the entire surface between it and the information recording layer, or in accordance with the formation pattern of the information recording layer.

Information is recorded on the information recording medium of the present invention formed in this way, as shown in FIG. This is done by aligning the liquid crystal layer present in the information recording area in the direction of the electric field due to the electric field generated.After information is recorded, when the information is reproduced using transmitted light, for example, the information recording area is exposed to the light between the resin body and the liquid crystal. Since the refractive index is the same, light A
The light B is transmitted through the area, whereas the light B is scattered in areas where no information is recorded, thereby providing a contrast with the information recording area.

The support 15 supports the information recording medium with strength, and does not need to be provided when the information recording layer has support, but it has a certain degree of strength that can support the information recording layer. If so, there are no particular restrictions on its material and thickness; for example, a flexible plastic film, or a rigid body such as glass or plastic sheet may be used. Specifically, when the information recording medium takes the form of a flexible film, tape, or disk, a flexible plastic film is used; when strength is required, a rigid sheet or inorganic material such as glass is used. materials etc. are used.

Furthermore, if necessary, a layer having an antireflection effect may be laminated on the other side of the support, or the thickness of the support may be adjusted to a level that can exhibit an antireflection effect, or a combination of both may be used. Antireflection properties may be imparted by.

The information recording medium of the present invention records electrostatic information in a visualized state by the alignment of liquid crystals, but those using conventional liquid crystal cells return to their original state when the electric field is removed.
In contrast to the information recording medium of the present invention, even if the electrostatic charge recorded on the resin body is removed, the information that has been oriented and visualized will not be erased and will have memory properties. There was found. Although the reason for this is unknown, it has been found that memory properties can be imparted to nematic liquid crystals by selecting a combination with a resin body. This memory property can be improved by heating during recording, and it can be erased by heating and can be reused.

Further, in the information recording medium of the present invention, as shown in FIG.
As shown in FIG. 3, by providing a dielectric mirror layer 16 between the photoconductive layer and the information recording layer, the information recording performance can be further improved.

Such a dielectric mirror layer is an insulating optical interference layer formed by alternately laminating material layers with different optical refractive indexes, such as zinc sulfide and magnesium fluoride, and allows information passing through the photoconductive layer to be It reflects light, imparts sufficient light absorption performance to the photoconductive layer, and can generate carriers with high sensitivity. Furthermore, since the amount of reflected light can be increased during reading, high-contrast reading is possible.

Furthermore, in the information recording medium of the present invention, by providing the charge retention layer 17 on the surface of the information recording layer, it is possible to suppress the attenuation of information charges during recording and to better maintain the orientation of the liquid crystal due to the electric field effect. Furthermore, the electrostatic information stored in the charge retention layer can be electrically reproduced.

Such a charge retention layer is made of highly insulating resin to suppress the movement of static charges, and has a specific resistance of 1014Ω.
Insulation and transparency of cm or more are required. Such resins include fluororesins such as polytetrafluoroethylene, fluorinated ethylene propylene, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymers,
Polyimide resin, polyetheretherketone resin, polyvaraxylylene, etc. can also be used, and a layer can be formed on the information recording layer by vapor deposition, sputtering, etc., or by dissolving it in a solvent and coating or dipping. can. Alternatively, a layer may be formed by attaching a film of the above polymer via an adhesive or the like. The film thickness is preferably 0.1 μm to 10 μm.

Further, a charge injection prevention layer may be provided between the photoconductive layer and the dielectric mirror layer, or between the dielectric mirror layer and the information recording layer.

The charge injection prevention layer prevents the injection of charges from the electrode layer, and has the effect of suppressing the injection of opposite charges from the electrode side and maintaining the electric field. For the charge injection prevention layer, the same material as the charge retention layer forming material can be used,
The film thickness is preferably such that the film thickness does not cause the charge tunneling phenomenon, and is preferably at least 1000 Å or more.

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

FIG. 2 is a diagram for explaining the information recording method, and numeral 1 in the figure represents a counter electrode.

First, the counter electrode 1 can be made of the same material as the electrode forming material in the information recording medium, and can be laminated on a support or a metal plate. is placed opposite.

Next, a voltage is applied between the electrodes 1.13 by the power supply V. In addition, when recording on this information recording medium, the memory property can be further improved by heating the information recording medium by, for example, resistance heating (not shown) embedded in the support and heating the liquid crystal to a temperature at which it exhibits a liquid crystal phase. can be improved.

When information light 18 is incident from the information recording medium 3 side in this temperature range, photocarriers generated in the photoconductive layer where the light has entered are accumulated at the information recording layer interface due to the electric field with electrode 1, and The liquid crystal phase in the information recording layer can be oriented by the electric field formed therebetween.

Also, some liquid crystals operate at low voltage, so
When setting the applied voltage, consider the electrodes, air gap,
By appropriately setting the voltage distribution between the information recording media, the voltage distribution applied to the information recording layer may be appropriately set in the operating voltage range of the liquid crystal.

This information recording method enables planar analog recording,
Since alignment at the level of liquid crystal particles can be obtained, high resolution can be obtained similar to silver salt photography, and the exposed pattern is visualized and retained as a result of the alignment of the liquid crystal phase.

The manual method of manually applying information to the information recording medium of the present invention includes a method using an electrostatic camera and a method using a laser.

In an electrostatic camera, the recording member is formed by a counter electrode 1 and an information recording medium 3 instead of the photographic film used in a normal camera, and a mechanical shutter can also be used. It also uses a shutter.

In addition, optical information is transmitted using prisms and color filters.
Separates into R%G and B light components and takes out as parallel light R,
Color photography can also be performed by forming one frame with three sets of information recording media separated into G and B, or by arranging RlG and B images on one plane and making one frame into one set.

For recording methods using lasers, the light sources include argon laser (514,488 nm), helium-neon laser (633 nm), and semiconductor laser (780 nm).
(nm, 810 nm, etc.) can be used, and the counter electrode and the information recording medium are brought into close contact with each other in planar form, or are faced to each other at a fixed interval and a voltage is applied. In this state, laser exposure corresponding to image signals, character signals, code signals, and line drawing signals is performed by scanning. Analog recording such as images is performed by modulating the light intensity of the laser, and digital recording such as characters, codes, and line drawings is performed by ON-OFF control of the laser light. Further, halftone dots in an image are formed by applying dot generator ON-OFF control to laser light.

Note that the spectral characteristics of the photoconductive layer in the information recording medium do not need to be panchromatic, but only need to be sensitive to the wavelength of the laser light source.

In addition to recording information on the information recording medium of the present invention using a counter electrode as described above, writing can be performed directly using corona charging, a bottle electrode, an ion current head, an electron beam, or ion implantation. Information charges may be applied to the surface of the information recording layer.

Information recorded by the alignment of liquid crystals is visible information that can be read visually, can be enlarged and read using a reflective projector, and can also be read using reflected light using laser scanning or CCD. By reading, information can be read with high precision.

[Action and effect of invention]

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 an electro-optic effect can be easily obtained. In addition, recorded information can be read by the contrast between scattered light and transmitted light without using a polarizing plate, and since the information recording layer is made uniformly thin using coating technology, the gap between the information charge and the conductive layer is reduced. It can be made uniformly small, it is possible to produce a large-area information recording medium, and it is also possible to record and reproduce high-resolution images.

That is, the information recording medium of the present invention is opaque due to light scattering when no electric field is applied, but when an electric field is applied, the liquid crystal phase is oriented, and its optical refractive index and the optical refractive index of the resin body are approximately equal to each other. By opening the same piece, the information recording section can be made transparent, eliminating the need for a polarizing plate when reproducing information, and simplifying the optical system when reading information.

Furthermore, in the information recording medium of the present invention, by providing a dielectric mirror layer between the photoconductive layer and the information recording layer, it becomes possible to form a visible image with high sensitivity, high contrast, and high quality. , which can perform highly accurate readings over a wide wavelength range.

As described in the prior art section, when a transmissive or light-reflective conductive layer is used, reading is achieved by sacrificing the light absorption performance of the counter electrode, whereas in the present invention, a dielectric layer is used. By providing a mirror layer, sufficient light absorption performance can be imparted to the photoconductive layer, allowing information to be recorded with high sensitivity.On the other hand, since the amount of reflected light can be increased during reading, high-contrast reading is possible. It is what it is.

Further, since there is no need to separate the recording wavelength and the reading wavelength, there is no restriction on the recording wavelength range or the reading wavelength range. Furthermore, since the information recording medium of the present invention does not require full-surface exposure, there is little noise in the unexposed portions, and a high-quality visible image can be obtained.

Furthermore, by providing a charge retention layer on the surface of the information recording medium of the present invention and a charge injection prevention layer between the conductive layer and the photoconductive layer, the orientation of the liquid crystal phase in the information recording layer - the preservation of visible information can be improved. It is possible to improve the permanence of information records.

By providing a charge retention layer, the ability to retain information charges themselves can be improved, and electrostatic information can also be reproduced electrically, so information can be reproduced both optically and electrically. I can do it.

Examples will be described below.

[Example 1] Bisazo pigment 3 having the above structure as a charge generating material
1 part and 1 part of polyvinyl acetal resin were adjusted to 2% solid content with a mixed solvent of dioxane:cyclohexan=1:l.
00g solution was sufficiently dispersed with a ball mill, and the solution was
It was coated on the 170 side of a glass substrate with a TO transparent electrode (film thickness: approx. 500^, resistance value 280 Ω/port) using a blade coater with a 2 mil gap, and dried at 100°C for 1 hour to form a film with a thickness of 0.3 μm. A charge generation layer was formed.

Next, P-diethylaminobenzaldehyde-N-phenyl-benzylhydrazone 15B and polycarbonate resin (Mitsubishi Gas Chemical Newpilon S-
100) 10 parts of dichloromethane:1,1.2-
) Solid content 17 in a mixed solvent of dichloromethane = 4 = 6,
A solution adjusted to 8% was prepared, and this solution was applied onto the charge generation layer formed above using a blade coater with a gap thickness of 2 mil, and dried at 80° C. for 2 hours to form a charge transport layer with a thickness of 10 μm. A laminated photoconductive layer was formed.

Furthermore, ZnS (refractive index 2.37>) and MgFz (refractive index 1.38>) were alternately laminated on this photoconductive layer, and ZnS was further laminated as the top layer to form a dielectric mirror layer.

Next, cyanobiphenyl liquid crystal (BDH B44,
Δn=0.262, N-I transition 100°C) 0°28 and P
MMA (0R-80 manufactured by Mitsubishi Rayon ■) OJg was dissolved in 1,2-dichloroethane to prepare a 10 wt % solution, which was coated on the dielectric mirror layer using a blade coater. Dry in an oven at 80°C for about 1 hour, and the liquid crystal is dispersed in PMMA to form an opaque film with a thickness of 8 μm.
An information recording layer of the present invention was prepared.

This information recording medium and ITO transparent electrode (film thickness: approximately 500^
A glass substrate having a resistance value of 280 Ω/hole) and a polyester film having a thickness of 10 μm were used as spacers and were placed facing each other as shown in FIG. Next, a DC voltage of 7 is applied between both electric currents, with the information recording medium side being positive and the electrode side being negative.
When a gray scale was projected and exposed for 0.1 seconds from the information recording medium side at the same time as 50μ was applied, it was confirmed that the liquid crystal phase in the recording layer was oriented by the electrostatic latent image, and that the liquid crystal phase changed depending on the exposure amount. It was found that the orientation of the phases was different and that it was possible to reproduce halftones.

When this medium was confirmed using reflected light, sufficient contrast was obtained even on the low exposure side of the gray scale, and an image could be confirmed. This image retained its image even after being left at room temperature for 10 days.

Further, even if the information recording medium was immersed in water immediately after image formation to eliminate the charge, the image remained in memory.

Furthermore, the image was erased by leaving this information recording medium on a hot plate at 60° C. for 3 minutes, and the same recording and erasing operations could be repeated.

[Example 2] An information recording medium was prepared in the same manner as in Example 1, except that the stacking order of the charge generation layer and the charge transport layer was different from that in Example 1, and information was recorded in the same manner. The results were obtained.

[Example 3] Composition of 10 g of PoIJ-N-vinylcarbazole (manufactured by Anan Koyo ■), 210 g of 2,4,7-trinitrofluoreno, 2 g of polyester resin (binder: Byron 200, manufactured by Toyobo ■), and 90 g of tetrahydrofuran. A mixed solution with
Glass substrate (1 m
The photoconductive layer was coated on the ITO surface side of the film with a thickness of 10 μm using a doctor blade and dried under ventilation at 60° C. for about 1 hour to form a single-layer photoconductive layer with a thickness of 10 μm.

In addition, in order to completely dry it, it was naturally dried for another day.

Next, a dielectric mirror layer was formed on this photoconductive layer in the same manner as in Example 1.

Cyanobiphenyl liquid crystal (manufactured by BDH, 844) 0
゜28 and PMMA (Mitsubishi Rayon ■, 5R-80)
0.3g dissolved in 1°2-dichloroethane 10
A wt% solution was prepared and applied onto the dielectric mirror layer using a blade coater. It was dried in an oven at 80° C. for about 1 hour to form an opaque information recording layer with a thickness of 8 μm in which liquid crystal was dispersed in PMMA, thereby producing an information recording medium of the present invention.

When electrostatic information was recorded on this information recording medium in the same manner as in Example 1, similar results were obtained.

[Example 4] An information recording medium was produced in the same manner as in Example 1 without providing the dielectric mirror layer in Example 1, and electrostatic information was recorded on this information recording medium in the same manner as in Example 1. It was confirmed that the liquid crystal phase in the recording layer was oriented using an electric latent image, and the orientation of the liquid crystal phase varied depending on the exposure amount (electric field strength), and it was possible to reproduce halftones. It was found that, if not, the gray scale could be confirmed although the contrast ratio was slightly inferior compared to the information recording medium of Example 1.

These information recording media were also tested for memory properties in the same manner as in Example 1, and similar results were obtained.

Similarly, when information was recorded on the information recording media of Examples 2 and 3 without providing a dielectric mirror layer, the same results as above were obtained.

[Example 5] Using the information recording medium obtained in Example 1, an image was obtained by exposing in the same manner as in Example 1 using a chrome mask plate with lines and spaces instead of gray scale. Ta.

When this medium was read by specular reflection using a microscope, it was found that 6
．． It was confirmed that the resolution was down to 6 μm.

[Brief explanation of drawings]

FIG. 1 is a schematic sectional view of the information recording medium of the present invention, FIG. 1(a) is a schematic diagram before information is recorded, and FIG. 1(b) is a state of information recording and reproduction of the information recording medium after information recording. FIG. 1(c) is a diagram illustrating another example of the information recording medium of the present invention, and FIG. 2 is a diagram illustrating an information recording method using a counter electrode. In the figure, 1 is a counter electrode, 3 is an information recording medium, 11 is a resin body, 12 is a liquid crystal phase, 13 is an electrode layer, a photoconductive layer, 15 is a support body, 16 is a dielectric body, 17 is a charge retention layer, 18 indicates pattern exposure, passing light, and B indicates scattered light. 14 is the Ra layer, A is the transparent applicant.

Claims (4)

[Claims] (1) An information recording medium in which a photoconductive layer and an information recording layer are sequentially provided on an electrode layer, wherein the information recording layer is a resin body in which a liquid crystal phase is dispersed and fixed, and the resin body and the liquid crystal substance are bonded together. An information recording medium characterized in that the optical refractive indexes of the two are selected so that the optical refractive indexes of the two are substantially the same. (2) The information recording medium according to claim 1, wherein the information recording layer is provided on the photoconductive layer via a dielectric mirror layer. (3) A resin body in which a liquid crystal phase is dispersed and fixed, and an information recording layer selected so that the optical refractive index of the resin body and the liquid crystal substance almost match is provided on the electrode layer via a photoconductive layer. Electrostatic information, characterized in that an information recording medium and a counter electrode are arranged, electrostatic information is recorded by exposure while applying a voltage between both electrodes, and the electrostatic information recording is reproduced as visible information. Recording and playback method. (4) A method for recording and reproducing electrostatic information, which comprises reproducing the visualized electrostatic information recording using transmitted light or reflected light.