JP3204769B2 - Information recording medium and information recording / reproducing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information recording medium capable of recording and storing electrostatic information as visible information, and a method for recording and reproducing the information.

[0002]

2. Description of the Related Art Liquid crystal display devices are used for displays for office automation equipment such as word processors and laptop computers. In these, a liquid crystal phase is sandwiched between transparent substrates such as a glass or plastic substrate provided with a transparent electrode film, and information such as images is obtained by applying a voltage between both electrodes using a single matrix or an active matrix. To display. As this method, there are a TN type, an STN type, a dynamic scattering type operating by current effect, a cholesteric-nematic phase transition, and more recently, a type combining a polymer and a liquid crystal.

In a device in which a nematic liquid crystal is dispersed and fixed in a polymer resin, a voltage is applied by matching the ordinary light refractive index of the liquid crystal material with the refractive index of the polymer resin to align the orientation of the liquid crystal material in the voltage application direction. When a voltage is not applied, the orientation of the liquid crystal material becomes non-uniform, and the light is scattered at the interface between the liquid crystal material and the polymer resin or in the liquid crystal phase fixed and dispersed, so that the liquid crystal material is made opaque, transparent and opaque. Are indicated by. A liquid crystal display element in which a nematic liquid crystal is dispersed and fixed in a polymer resin can have a large area, a short response time, particularly a short fall time, a high light use efficiency without a polarizing plate, and a wide and uniform viewing angle. In recent years, it has been reported that a window is used for a light control sheet or a projection display.

[0004] The present invention is also applied to a projection type display or a computer display, and has an advantage that its fall time can be shortened to 1 to 30 ms compared to a TN type or STN type display which is most frequently used. In such a liquid crystal display element, an AC voltage is applied in a state of being sandwiched between electrodes, and display and erasure are performed by turning on and off the voltage. At this time, there is a report that a slight hysteresis occurs in the voltage-to-light transmittance, and a difference occurs in the transmittance between when the applied AC voltage is increased and when the applied AC voltage is decreased. In this case, the initial transmittance, that is, the opaque state is restored.

As a method of displaying information such as an image, an ON-OFF operation is performed for each pixel by sandwiching the matrix electrode.
In general, an image pattern electrode is also used. In addition, when forming a composite film of a polymer and a liquid crystal, for example, there is a device that irradiates image-like ultraviolet rays using a UV-curable polymer material, but all of them make fixed information blink. . On the other hand, as a device having a memory property, there is a device using a cholesteric-nematic phase transition. In this method, a sandwich structure in which liquid crystal is sandwiched between transparent electrodes is used.

[0006]

SUMMARY OF THE INVENTION The present invention relates to an information recording medium having a structure in which an information recording layer is laminated on an electrode layer and for recording electrostatic information in a visible state. It is another object of the present invention to provide an information recording medium and an information recording / reproducing method which have a high durability.

[0007]

According to the information recording medium of the present invention, a photoreceptor having a photoconductive layer provided on an electrode layer is disposed so as to face the same, and exposure is performed while applying a voltage between the two electrodes. An information recording medium for recording and storing as visible information, wherein the information recording medium has an information recording layer made of an acrylic resin or a methacryl resin in which a liquid crystal phase is dispersed and fixed on an electrode layer, and the information recording layer is Wherein the weight average molecular weight of the acrylic resin or methacrylic resin is 10,000 to 100,000, and the ratio of liquid crystal used to the total amount of the resin and the liquid crystal material is 30 to 60% by weight. .

In the information recording medium of the present invention, a photoreceptor having a photoconductive layer provided on an electrode layer is disposed so as to face, and exposure is performed while applying a voltage between the two electrodes to convert electrostatic information into visible information. An information recording medium for recording and storing, wherein the information recording medium is
An information recording layer made of an acrylic resin or a methacrylic resin having a liquid crystal phase dispersed and fixed thereon is laminated on the electrode layer,
The acrylic resin or methacrylic resin in the information recording layer has a weight average molecular weight of 10,000 to 100,000 and an acid value of 2 or more, and the ratio of liquid crystal to the total amount of the resin and the liquid crystal material is 30% by weight. % To 60% by weight.

In the information recording medium of the present invention, a photosensitive member having a photoconductive layer provided on an electrode layer is disposed so as to face, and exposure is performed while applying a voltage between the two electrodes. An information recording medium for recording and storing, wherein the information recording medium is
An information recording layer and a charge retention layer each made of an acrylic resin or a methacrylic resin having a liquid crystal phase dispersed and fixed on the electrode layer are sequentially laminated, and the weight average molecular weight of the acrylic resin or the methacrylic resin in the information recording layer is 10,000 to 10 And a ratio of the use of the liquid crystal to the total amount of the resin and the liquid crystal material of 30 to 60% by weight. The liquid crystal phase is a nematic phase or a cholesteric phase at a use environment temperature.

[0010] The information recording layer is characterized in that, prior to information recording, the information recording layer is subjected to a heat treatment at a temperature not lower than room temperature and not higher than an isotropic phase transition temperature of liquid crystal.

[0011] The resin is characterized in that it has a glass transition temperature equal to or higher than a use environment temperature.

The information recording layer is characterized by being laminated on an electrode layer via a charge injection preventing layer.

The information recording / reproducing method of the present invention is directed to an information recording medium in which an information recording layer composed of an acrylic resin or a methacrylic resin in which a liquid crystal phase is dispersed and fixed on an electrode layer, wherein the resin has a weight average molecular weight. An information recording medium which is 10,000 to 100,000, and wherein a usage ratio of liquid crystal to the total amount of the resin and the liquid crystal material is 30% by weight to 60% by weight;
A photoconductor provided with a photoconductive layer on the electrode layer is disposed to face, and the electrostatic information is recorded by exposing from the photoconductor or the information recording medium side while applying a voltage between the two electrodes, thereby making the electrostatic information visible. It is characterized in that it is recorded and stored as information and reproduced at an arbitrary time.

The information recording / reproducing method of the present invention is directed to an information recording medium in which an information recording layer made of an acrylic resin or a methacrylic resin having a liquid crystal phase dispersed and fixed on an electrode layer, wherein the resin has a weight average molecular weight. An information recording medium having 10,000 to 100,000, an acid value of 2 or more, and a use ratio of liquid crystal of 30% to 60% by weight based on the total amount of the resin and the liquid crystal material; A photoconductor provided with a photoconductive layer is disposed opposite to the photoconductor and the electrostatic information is recorded by exposing from the photoconductor or the information recording medium side while applying a voltage between both electrodes, and the electrostatic information is recorded as visible information. It is stored and played back at any time.

It is characterized in that the visible information is reproduced by transmitted light or reflected light.

FIGS. 1A and 1B are diagrams for schematically explaining a cross section of an information recording medium of the present invention. FIG. 1A is a schematic diagram before information recording, and FIG. 1B is a diagram showing information on the information recording medium after information recording. FIG. 4C is a diagram for explaining a recording / reproducing state, and FIG. 4C is a diagram showing another example of the information recording medium of the present invention.

In the figure, 3 is an information recording medium, 11 is resin, 12
Is a liquid crystal phase, 13 is an electrode layer, 14 is a charge holding layer, 15 is a support, and 16 is a charge injection preventing layer.

First, as shown in FIG. 1A, the information recording medium of the present invention has a structure in which an information recording layer composed of a liquid crystal phase 12 and a resin 11 is laminated on an electrode 13. The information recording layer is obtained by dispersing and fixing a low-molecular liquid crystal material 12 in a resin 11. As the liquid crystal material, a nematic liquid crystal that exhibits a nematic phase and a cholesteric phase at an ambient temperature of use,
Cholesteric liquid crystals or mixtures thereof can be used. For example, the following can be used as the nematic material.

[0019]

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[0020]

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[0021]

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[0022]

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When a liquid crystal material is selected, a material having a large anisotropy in refractive index is preferable because contrast can be obtained.

The resin 11 is an acrylic resin or a methacrylic resin, and is a solvent-soluble resin having compatibility with a solvent common to the liquid crystal material, such as a methyl acrylate resin.
Examples thereof include methyl methacrylate resin, and homopolymers thereof such as ethyl ester, isobutyl ester and t-butyl ester, and acrylonitrile resin and a copolymer mainly composed of these resins. The weight average molecular weight of the acrylic resin or the methacrylic resin is preferably 10,000 to 100,000. When the weight average molecular weight of the resin is 100,000 or more, the solubility in a solvent is deteriorated, the coatability is reduced, and there are problems such as loss of memory properties.
Examples of such an acrylic resin include BR-80, BR-83, BR-87 and BR-5 manufactured by Mitsubishi Rayon Co., Ltd.
2, BR-107, BR-106, BR-88, BR-
85, BR-100, BR-101, LR-1065,
LR-186, LR-143, LR-158, LR-1
77, LR-162, LR-167, LR-472, L
R-637, LR-574, LR-016, LR-15
5, LR-237, LR-254, LR-257, LR
-286, LR-1503, LR-1573, LR-1
589 and the like.

The acid value of the acrylic resin is preferably 2 or more, and if the acid value is less than 2, the memory property is reduced. Also, it is preferable to use one whose glass transition temperature is equal to or higher than the operating environment temperature of the information recording medium. If the glass transition temperature is lower than the operating environment temperature, even if electrostatic information is recorded, the information recording medium immediately becomes cloudy, Does not have the property.

In the information recording layer of the present invention, it is necessary to make a selection so that the optical refractive index of the resin and the optical refractive index of the aligned liquid crystal are substantially equal. Reflection and scattering occur at the interface between the liquid crystal and the resin, and a transparent state during recording cannot be obtained.

The proportion of the liquid crystal to the total amount of the resin and the liquid crystal material is preferably 30% by weight to 60% by weight. If the amount of the liquid crystal material used is small, the transparency at the time of non-recording is high, the contrast is low even if the information is recorded and the liquid crystal phase is oriented, and even if the used amount is too large, phenomena such as oozing of the liquid crystal occur. ,
In addition, it is not preferable because erasure of memory property occurs.

The information recording layer is formed by dissolving a resin and a liquid crystal material in a solvent, and coating the solution on the electrode layer with a general coater such as a blade coater, a roll coater, or a spin coater. Is done. As the solvent, chloroform, dichloromethane, benzene, toluene, xylene, tetrahydrofuran, dioxane, or the like can be used, and the coating solution is preferably adjusted to a coating solution having a solid content concentration of 30% by weight to 60% by weight. The thickness of the information recording layer after drying is 1 μm to 40 μm, preferably 4 μm.
It is good to be 20 μm to 20 μm.

When drying the solvent by heating the coating layer,
As the resin solidifies, the liquid crystal material undergoes phase separation, and the particle size is sub-μm.
It is considered that the liquid crystal phase is dispersed and fixed in the resin body to a certain degree. Further, in drying the coating liquid, it is necessary to remove the solvent while maintaining the temperature at or below the temperature at which the liquid crystal material changes to a random state, that is, a so-called isotropic phase. If the resin is dried and solidified in a state where the resin has transitioned to the isotropic phase, liquid crystallinity cannot be obtained, and the electro-optical effect will not be exhibited. This is considered to be because if the temperature is high at the time of drying, a sufficient phase separation state between the liquid crystal and the resin body cannot be obtained, and the resin and the liquid crystal are dried in a state of being dissolved.

Further, a radiation-curable resin in an uncured state, which is compatible with a liquid crystal material in a monomer or oligomer state, such as an acrylate ester or a methacrylate ester, is used as the resin. After the coating liquid is dried, it may be irradiated with radiation and cured to form an information recording layer.

The material of the electrode layer 13 has a specific resistance of 10 ⁶ Ω.
There is no particular limitation as long as it is not more than cm, and examples thereof include a metal conductive film, an inorganic metal oxide conductive film such as indium tin oxide (ITO), and an organic conductive film such as a quaternary ammonium salt. Such an electrode is formed on a support or an information recording layer by a method such as vapor deposition, sputtering, CVD, coating, plating, dipping, and electrolytic polymerization. Further, the film thickness needs to be changed depending on the electrical characteristics of the material constituting the electrode and the applied voltage at the time of information recording. For example, the thickness of the ITO film is about 100 to 3000 °, and the entire surface between the information recording layer and Alternatively, it is formed according to the formation pattern of the information recording layer.

The information recording on the information recording medium of the present invention thus formed is performed by the information recording method shown in FIG. This is performed by orienting the liquid crystal phase existing at the information recording portion by an electric field formed between the information recording and reproducing information by, for example, transmitted light as shown in FIG. In the information recording portion, the light A is transmitted because the optical refractive indexes of the resin and the liquid crystal are the same, while the light B is transmitted in the portion where no information is recorded.
Are scattered and contrast with the information recording section can be obtained.

The support 15 supports the information recording medium in a strong manner, and is not required to be provided when the information recording layer has a supporting property. However, the support 15 has a certain strength capable of supporting the information recording layer. The material and thickness are not particularly limited as long as it has a rigid material such as a flexible plastic film or glass or a plastic sheet. Specifically, when the information recording medium takes the form of a flexible film, tape, disk, or card, a flexible plastic film is used, and when strength is required, a rigid sheet, glass, or the like is used. Are used.

When the recorded information is reproduced by transmitted light, a layer having an anti-reflection effect is laminated on the other surface of the support, if necessary, or the anti-reflection effect is exhibited. The anti-reflection property may be imparted by adjusting the support or the like to a desired film thickness or by combining the two.

A conventional liquid crystal display device is a device in which a liquid crystal phase is dispersed and fixed in a TN-type or STN-type liquid crystal cell in which liquid crystal is sandwiched between electrodes or a polymer resin. When the voltage between them is removed, it returns to the original state and there is no memory property.

However, the information recording medium of the present invention
The information is recorded and stored in a state where the electrostatic information on the information recording layer is visualized by the orientation of the liquid crystal.By recording the information in the form of an electrostatic charge on the surface of the information recording layer, the information has gradation. It can be recorded and stored, and once recorded, the visible information is not erased unless heated, even if the static charge is removed, and has a memory property.

Although the detailed reason is unknown, generally, when a DC voltage is applied in a state where an information recording layer in which a liquid crystal phase is dispersed in a resin is sandwiched between two electrodes, no memory property is exhibited and the voltage is not applied. It operates at the moment when it is done, but the transmittance returns to almost the initial state in a short time due to dielectric relaxation.
It responds again at the moment when the voltage is removed, and returns to the initial state again. However, when an electrode layer is provided on only one of the information recording layers and electrostatic information is applied to the surface of the information recording layer, the electrostatic information is accumulated in the resin on the surface of the information recording layer, and the electrostatic information and the information recording medium are stored. It is considered that the orientation of the liquid crystal phase can be maintained permanently by the electric field formed between the electrodes.

The method for recording information on the information recording medium of the present invention includes corona charging which can record information electrostatically on the surface of the information recording layer, or opposing the information recording medium of the present invention to an electrode via an air gap. Then, by applying a voltage between both electrodes in a pattern, air discharge or electric field formation based on Paschen's law is performed, and electrostatic information is recorded on the information recording layer.

Further, the information recording medium of the present invention is disposed opposite to a photoreceptor having a photoconductive layer via an air gap, and pattern exposure is performed while applying a voltage between the two electrodes. Electrostatic information having a characteristic can be recorded on the information recording layer.

The present inventors also concluded that the memory property of the information recording layer in the present invention is such that, prior to information recording, the information recording layer is heated to a temperature higher than room temperature and lower than a temperature at which a liquid crystal material transitions to an isotropic phase. By doing so, it has been found that it is further improved. If the information recording layer is heated above the temperature at which the liquid crystal material transitions to the isotropic phase, the information recording layer becomes transparent, and the liquid crystal material does not exhibit liquid crystallinity, which is not preferable.

Although the detailed reason is unknown, it is thought that the memory property is improved by the interaction of the interface between the liquid crystal phase and the resin body in the information recording layer. After once heating the information recording layer to the critical temperature where the interface interaction changes greatly,
It is preferable to use the information recording at a temperature slightly lower than this, that is, a state in which the interaction between the interfaces is large. The degree of the heating is appropriately set depending on the types of the liquid crystal and the resin, the composition ratio, and the like. This interfacial interaction is thought to be due to a structural change or a significant change in interfacial interaction, which persists upon cooling or standing.

The information recording medium of the present invention and an electrode having a conductive layer formed in a pattern are opposed to each other via an air gap, and a voltage is applied to the information recording layer in a pattern to apply electrostatic information to the information recording layer. As a result, it was confirmed that the resolution was obtained at a portion where the line of the conductive layer of 6 μm and the line of the space of 6 μm were alternately arranged.

Although the resolution is closely related to the film thickness of the information recording medium, in the information recording medium of the present invention, the accuracy of the film thickness is precisely controlled when coating the information recording layer. A spacer for gap control is not required unlike a laminating method or an encapsulating method in which a sandwich is made between them, and high-resolution information can be recorded, and no defect occurs.

Further, the visualized information once recorded is erased by heating to a temperature higher than the critical temperature at which the interaction between the interface between the polymer resin and the liquid crystal phase dispersed and fixed greatly changes, and the information recording medium is reused. be able to. The visualization information is also erased by heating above the isotropic phase transition temperature of the liquid crystal phase, but in this case it becomes transparent once, but upon cooling, it returns to cloudy and opaque original state.

In the information recording medium of the present invention,
By providing the charge holding layer 14 on the information recording layer 11 as shown in FIG. 1 (c), it is possible to suppress the decay of information charges during recording and to maintain the orientation of the liquid crystal by the electric field effect. In this case, it is possible to electrically reproduce the electrostatic information stored in the charge holding layer.

Such a charge retaining layer is made of a highly insulating resin in order to suppress the movement of electrostatic charges, and is required to have an insulating property and a transparency of 10 ¹⁴ Ω · cm or more in specific resistance. As such a resin, a fluorine resin such as polytetrafluoroethylene, fluorinated ethylene propylene, tetrafluoroethylene-perfluoroalkylvinyl ether copolymer, a polyimide resin, a polyether ether ketone resin, and polyparaxylylene are used. The layer can be formed on the information recording layer by vapor deposition, sputtering, or the like, or by dissolving in a solvent and coating and dipping. Further, a layer may be formed by attaching a film of the above polymer via an adhesive or the like. The thickness is preferably 1 μm to 40 μm.

In the information recording medium shown in FIGS. 1A and 1C, a charge injection preventing layer 16 may be provided between the electrode layer 13 and the information recording layer 11. The charge injection prevention layer is
This prevents charge injection from the electrode layer, which has the effect of suppressing the injection of reverse charge on the electrode side and maintaining the electric field. The charge injection preventing layer may be the same as the charge holding layer forming material, and may be laminated to a thickness that does not cause a charge tunneling phenomenon, that is, a thickness of at least 1000 mm or more.

Also, photoconductive fine particles or conductive fine particles may be contained in the charge holding layer and / or the charge injection preventing layer.

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

FIG. 2 is a view for explaining an information recording method. In the figure, reference numeral 1 denotes a photoconductor, 5 denotes a photoconductive layer support, 7 denotes a photoconductor electrode, 9 denotes a photoconductive layer, and 17 denotes a power supply.

First, a 1000 mm thick indium tin oxide (IT) was placed on a photoconductive layer support 5 made of 1 mm thick glass.
O), and a transparent electrode 7 of 10 μm
The photoconductor 1 is formed by forming a photoconductive layer 9 having a thickness of about 1 mm.

As shown in FIG. 1A, an information recording medium 3 is disposed on the photosensitive member 1 with a gap of about 10 μm.

Next, a voltage is applied between the electrodes 7 and 13 by the power supply 17 as shown in FIG. In a dark place, the photoconductive layer 9 is a high-resistance body.

In this state, when light 18 is incident from the photoreceptor 1 side, the photoconductive layer 9 in the portion where the light is incident exhibits conductivity and becomes a low-resistance body, and information charges are accumulated in the information recording layer. Liquid crystal orientation occurs at the charge storage site in the information recording layer. Also, even if there is a uniform fog charge in advance, the charge is further accumulated in the portion where light is incident,
Information can be recorded by contrast with an unexposed portion.

As described above, when forming information charges, some liquid crystals operate at a low voltage. Therefore, when setting the applied voltage, the voltage distribution among the photoconductor, the air gap, and the information recording medium is determined. By appropriately setting, the voltage distribution applied to the information recording layer may be set in the operating voltage region. When recording on the information recording medium, the information recording medium can be heated by, for example, passing current through the electrode layer and heated by energization to further improve the memory property.

According to this information recording method, planar analog recording is possible, and alignment at the level of liquid crystal particles can be obtained, so that high resolution can be obtained in the same manner as in silver salt photography, and the exposure pattern depends on the alignment of the liquid crystal phase. It is kept as a visible image. This information can be input using a high-resolution electrostatic camera,
There is also a recording method using a laser.

The information light may be incident from the photoreceptor side, or may be incident from the information recording medium side. First, a high-resolution electrostatic camera forms a recording member by a photoreceptor 1 and an information recording medium 3 in place of a photographic film used in a normal camera, and a mechanical shutter can be used. An electric shutter could also be used.

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

As a recording method using a laser, an argon laser (514.488 nm) is used as a light source,
A helium-neon laser (633 nm) or a semiconductor laser (780 nm, 810 nm, or the like) can be used. The photosensitive member and the information recording medium are brought into close contact with each other in a planar state, or they are opposed to each other at a certain interval, and a voltage is applied. In this state, laser exposure corresponding to the image signal, character signal, code signal, and line drawing signal is performed by scanning. Analog recording such as an image is performed by modulating the light intensity of a laser, and digital recording such as characters, codes, and line drawings is performed by ON-OFF control of a laser beam. In the case where halftone dots are formed in an image, the laser light is formed by performing dot generator ON-OFF control. Note that the spectral characteristics of the photoconductive layer in the photoreceptor need not be panchromatic, but may be any as long as they have sensitivity to the wavelength of the laser light source.

The information recording on the information recording medium of the present invention can be performed by corona charging, a pin electrode, an ion current head, an electron beam, or ion implantation, in addition to the information recording using the photosensitive member as described above. The information charge may be directly applied to the information recording layer surface by writing.

Further, the information recording medium of the present invention is uniformly charged over the entire surface of the medium by corona charging or the like, the liquid crystal is oriented, and the entire medium is made transparent. The orientation of the liquid crystal phase in the information recording layer can be returned to a random state, and the information can be recorded by making the liquid crystal phase opaque by scattering. Further, the entire opaque information recording medium is divided into several blocks, for example, an information recording layer portion of a certain block is an area where information can be recorded by the action of an electric field according to information, and the other blocks are in a transparent state as described above. After that, a block in which information can be recorded by a heating means such as a thermal head may be used.

The information recorded by the orientation of the liquid crystal is visible information that can be visually read, and can be read by enlarging it with a reflection type projector, and further using laser scanning or CCD. Information can be read with high accuracy by reading with reflected light or transmitted light.

[0063]

The information recording medium of the present invention has an information recording layer in which a liquid crystal phase is dispersed and fixed in an acrylic resin or a methacrylic resin on an electrode layer. The orientation of the phase is maintained permanently, and the recorded information has a memory property. Further, this memory property, by providing a charge holding layer on the information recording layer, or by providing a charge injection prevention layer between the electrode layer and the information recording layer, the orientation of the liquid crystal phase in the information recording layer, That is, it is possible to enhance the preservability of visible information and enhance the durability of information recording. Further, by providing the charge holding layer, the electrostatic information recorded on the charge holding layer can be electrically reproduced, and the information can also be reproduced electrically.

The information recording medium of the present invention is a medium in which a liquid crystal is dispersed in a polymer to form an information recording layer. The information recording layer can easily obtain an electro-optical effect, and can record analog information.
It can be stored in memory. The liquid crystal phase in the information recording layer is opaque due to light scattering when no electric field is applied by the information charge, and the liquid crystal phase is oriented by the action of the electric field at the portion where the information charge is applied, and its light refractive index and resin light refraction. The recording rate can be made almost the same, the information recording section can be made transparent, and the recorded information can be reproduced by the contrast between scattered light and transmitted light without using a polarizing plate, and the optical system for reading is simplified. It is a good thing.

Further, in the information recording medium of the present invention, the information recording layer can be uniformly thinned by a coating technique.
The gap between the information charge and the conductive layer on the surface of the information recording layer can be made uniform and small, a large-area information recording medium can be manufactured, and a high-resolution image can be recorded and reproduced.

Hereinafter, embodiments will be described.

[0067]

[Example 1] Cyanobiphenyl-based liquid crystal (E4 manufactured by Merck)
4, Δn = 0.262, NI transition 100 ° C) 0.3 g
And acrylic resin PMMA (Mitsubishi Rayon Co., Ltd.,
BR-83, Tg = 105 ° C., weight average molecular weight 40,000, acid value 2) 0.2 g were dissolved in chloroform to prepare a 15% by weight solution, and this solution was sputtered on a 1 mm thick glass substrate. Indium tin oxide (ITO) electrode
The resultant was coated on a glass substrate electrode having a thickness of 2,000 ° by a blade coater, and dried in an oven maintained at 80 ° C. for 1 hour to produce an information recording medium of the present invention. The thickness of the information recording layer was 6 μm.

[0068]

Example 2 Cyanobiphenyl liquid crystal (E4 manufactured by Merck)
4, Δn = 0.262, NI transition 100 ° C) 0.3 g
And acrylic resin PMMA (Mitsubishi Rayon Co., Ltd.,
BR-87, Tg = 105 ° C., weight average molecular weight of 25
And an acid value of 10.5) were dissolved in chloroform to prepare a 15% by weight solution, and this solution was sputtered on a 1 mm thick glass substrate to form indium tin oxide (IT).
O) An electrode was applied on a glass substrate formed by laminating electrodes at a thickness of 1000 ° using a blade coater and dried in an oven maintained at 80 ° C. for 1 hour to produce an information recording medium of the present invention. The thickness of the information recording layer was 6 μm.

[0069]

Example 3 Cyanobiphenyl liquid crystal (E4 manufactured by Merck)
4, Δn = 0.262, NI transition 100 ° C) 0.3 g
And acrylic resin PMMA (Mitsubishi Rayon Co., Ltd.,
BR-80, Tg = 105 ° C., weight average molecular weight 95,000
1,000, acid value 0) 0.2 g was dissolved in chloroform
A 5% by weight solution was prepared, and this solution was coated on a glass substrate having a thickness of 1 mm by sputtering with a blade coater on an electrode of a glass substrate formed by laminating an indium tin oxide (ITO) electrode to a thickness of 1000 ° by a sputtering method. Then, it was dried in an oven maintained at 80 ° C. for 1 hour to produce an information recording medium of the present invention. The thickness of the information recording layer was 6 μm.

[0070]

Example 4 Cyanobiphenyl liquid crystal (E4 manufactured by Merck & Co., Ltd.)
4, Δn = 0.262, NI transition 100 ° C) 0.3 g
And LR-343 (solid content 30) manufactured by Mitsubishi Rayon Co., Ltd.
% Toluene solution) (acrylic resin PMMA, Tg = 1)
05 ° C, weight-average molecular weight 100,000, acid value 2) 0.67
g was dissolved in chloroform to prepare a 15% by weight solution, and this solution was formed on a glass substrate having a thickness of 1 mm by sputtering an indium tin oxide (ITO) electrode to a thickness of 1000 ° to form a glass substrate. Was coated with a blade coater and dried in an oven maintained at 80 ° C. for 1 hour to produce an information recording medium of the present invention. Although the thickness of the information recording layer was 6 μm, uneven coating occurred.

[0071]

Example 5 (Comparative Example) Cyanobiphenyl-based liquid crystal (E44 manufactured by Merck, Δn = 0.262, NI transition 100)
C.) 0.3 g and 0.2 g of acrylic resin PMMA (manufactured by Mitsubishi Rayon Co., Ltd., BR-100, Tg = 105.degree. C., weight average molecular weight 120,000, acid value 0) were dissolved in chloroform and dissolved. A weight% solution was prepared, and this solution was coated on a glass substrate having a thickness of 1 mm by sputtering using a blade coater on an electrode of a glass substrate formed by laminating an indium tin oxide (ITO) electrode to a thickness of 1000 ° by a sputtering method. , 8
It was dried in an oven kept at 0 ° C. for 1 hour to produce an information recording medium of the present invention. Although the thickness of the information recording layer was 6 μm, uneven coating occurred.

[0072]

Example 6 Cyanobiphenyl liquid crystal (E4 manufactured by Merck & Co., Ltd.)
4, Δn = 0.262, NI transition 100 ° C) 0.3 g
And acrylic resin PMMA (Mitsubishi Rayon Co., Ltd.,
BR-52, Tg = 105 ° C., weight average molecular weight 85,000
1,000, acid value 0) 0.2 g was dissolved in chloroform
A 5% by weight solution was prepared, and this solution was coated on a glass substrate having a thickness of 1 mm by sputtering with a blade coater on an electrode of a glass substrate formed by laminating an indium tin oxide (ITO) electrode to a thickness of 1000 ° by a sputtering method. Then, it was dried in an oven maintained at 80 ° C. for 1 hour to produce an information recording medium of the present invention. The thickness of the information recording layer was 6 μm.

[0073]

Example 7 The surface of the information recording layer of the information recording medium obtained in Examples 1 to 6 was positively or negatively charged in a pattern by corona charging, allowed to stand at room temperature for 5 days, and then subjected to visible ultraviolet spectroscopy. The light transmittance (%) at 900 nm of the charged portion and the uncharged portion was measured using a container (UV-240 manufactured by Shimadzu Corporation). The results are shown in Table 1 below.

[0074]

[Table 1]

As can be seen from this table, it is understood that the information recording medium of the present invention has good transmittance holding performance in both positive and negative charging.

Next, after the information recording layer surface of the information recording medium obtained in Examples 1 to 6 was positively or negatively charged in a pattern by corona charging, a deflection microscope equipped with a heating stage (manufactured by Olympus Corporation) was used. ) Was used at a heating rate of 5 K / min, and the temperature at which the recording information returned to the scattering state was measured, whereby the erasing temperature (° C.) of the recorded information was measured. The results are shown in Table 2 below.

[0077]

[Table 2]

As described above, in the information recording medium of the present invention, the liquid crystal phase in the recording layer is oriented by the surface charge, and it is confirmed that the recording has permanence, and the recording is erased by heating. You can see it.

[0079]

Example 8 In Example 2, resin / liquid crystal (weight ratio)
An information recording medium was prepared in the same manner as in Example 2 except that the information recording layer had a ratio of 2/1, 3/2, 1/1, 2/3, and 1/2.

The surface of the information recording layer of each medium was positively or negatively charged in a pattern by corona charging, and then subjected to 5 K / m using a deflection microscope equipped with a heating stage (manufactured by Olympus Corporation).
The temperature at which the temperature returns to the scattering state from the transmission state is measured by heating at a heating rate of "in".
Was measured. The results are shown in Table 3 below.

[0081]

[Table 3]

As described above, in the information recording medium of the present invention, the liquid crystal phase in the recording layer is oriented by the surface charge, and it is confirmed that the recording has permanence, and the recording is erased by heating. You can see it.

[0083]

Ninth Embodiment The recording medium of Example 1 as it is and the recording medium heated to about 80 ° C. by an oven were negatively charged by corona charging.

For each of these media, 900 n of the charged portion immediately after charging and after leaving for 5 days at room temperature conditions
The light transmittance (%) at m was measured by a visible ultraviolet spectrometer (UV-240, manufactured by Shimadzu Corporation), and the effect of heating the information recording medium before recording was examined. The measurement results are shown in the table below.

[0085]

[Table 4]

As can be seen from the table, it is understood that the memory property is improved by heating the information recording medium before recording. The heating temperature is preferably higher. However, if the heating temperature is higher than the glass transition temperature of the resin, the resin and the liquid crystal phase are compatible with each other, and sufficient contrast cannot be obtained.

Next, when the recording medium on which the information was recorded was heated to 70 ° C., the transparency of the information recording portion was lost, and the information became white and opaque, and the information was erased.

[0088]

Example 10 (Preparation of Photoreceptor) An ITO film having a thickness of 1000 ° was formed on a sufficiently cleaned glass substrate having a thickness of 1.1 mm by a sputtering method to obtain an electrode layer.

On the electrode, a charge generating agent having the following structure

[0090]

Embedded image

3 parts by weight of a fluorenone azo pigment (manufactured by Nippon Kogaku Dyeing Co., Ltd.) and a polyester resin (manufactured by Toyobo Co., Ltd.)
Byron 200) 1 part by weight, 98 parts by weight of 1,4-dioxane and 98 parts by weight of anone were mixed, and dispersed for 6 hours with a paint shaker to obtain a coating liquid.
After coating at 00 rpm for 0.4 sec, 10
After drying at 0 ° C. for 1 hour, a charge generation layer having a thickness of 3000 ° was laminated.

On this charge generation layer, a charge transport agent having the following structure

[0093]

Embedded image

25 parts by weight of para-dimethylstilbene,
A coating liquid obtained by mixing 5 parts by weight of a polystyrene resin (manufactured by Denka, HRM-3), 102 parts by weight of 1,1,2-trichloroethane, and 68 parts by weight of dichloromethane was coated with a spinner at 300 rpm and 0.3 msec. Thereafter, the resultant was dried at 80 ° C. for 2 hours, a charge transport layer was laminated, and a photoconductive layer having a thickness of 20 μm comprising a charge generation layer and a charge transport layer was formed to prepare a photoreceptor.

As shown in FIG. 2, the photoconductor and the information recording medium manufactured in Example 1 were opposed to each other with a gap of 9 μm therebetween, and the photoconductor side was placed between both electrodes of the photoconductor and the information recording medium. 750 V was applied, and a gray scale was projected and exposed for 0.1 second, and the light transmittance of the exposed portion and the unexposed portion was measured in Example 7.
When the measurement was performed in the same manner, it was confirmed that recording according to the exposure information could be performed.

In place of the gray scale, a negative image of a silver halide photograph is projected and exposed, and the obtained information recording medium is read by using a film scanner (trade name: LS-3500, manufactured by Nikon Corporation) and printed by a printer. As a result, a positive image having a gradation characteristic corresponding to the negative image of the silver halide photograph could be reproduced.

[0097]

Example 11 A recording medium produced in the same manner as in Example 1 was disposed opposite to a patterned electrode in which a 6 μm line was disposed on a glass via a 6 μm space, and both ends of an electrode of the recording medium and a pattern electrode were arranged. When a DC voltage of 750 V and 0.1 sec was applied to the recording medium, it was confirmed that lines and spaces of 6 μm were resolved on the recording medium. In addition, it was confirmed that the resolution was maintained even after the recording medium was immersed in water and charges were removed.

[0098]

Embodiment 12 On the information recording layer formed in the same manner as in Embodiment 1, a fluororesin (trade name: Cytop, Asahi Glass Co., Ltd.)
Co., Ltd.) in a 5% fluorine solution (1500 rpm)
m: 30 seconds), allowed to stand at room temperature for one day, and dried in a vacuum oven at 80 ° C. to form a charge holding layer having a thickness of about 0.5 μm. Produced. When electrostatic information was recorded on this information recording medium in the same manner as in Example 10, it was confirmed that the information could be recorded similarly. The visible image was maintained even after the information recording medium was allowed to stand at room temperature for 20 days, and information charges could be read by a surface voltmeter.

[0099]

Example 13 A rosin ester resin (manufactured by Rika Hercules Co., Ltd.) was formed on the information recording layer formed in the same manner as in Example 1.
A 20% hexane solution of stevelite ester 10) was applied by spin coating (2000 rpm, 30 seconds), and then dried in an oven at 60 ° C. for 2 hours to obtain a film thickness of about 0.7.
A charge holding layer of μm was formed. Next, a-Se fine particles were vapor-deposited on the surface of the charge retaining layer using a vacuum vapor deposition machine (VPC-410 manufactured by Vacuum Kiko Co., Ltd.) under the following conditions.

First, the medium was fixed to a substrate holder for heating in a vacuum chamber so that the glass surface of the medium was in contact with the substrate, the substrate holder was heated to 70 ° C. with a degree of vacuum of 6 torr, and a-Se was heated by a resistance heating method. Was provided in the form of fine particles in the vicinity of the surface of the charge holding layer to produce an information recording medium of the present invention. Next, when electrostatic information was recorded on this information recording medium in the same manner as in Example 10, similar recording could be performed.

Further, even after the information recording medium was allowed to stand at room temperature for 20 days, the visible image was maintained, and the surface potential was reproduced by the surface voltmeter, indicating that the information was maintained.

[0102]

Embodiment 14 A fluororesin (trade name: Cytop, Asahi Glass) was formed by laminating an indium tin oxide (ITO) electrode to a thickness of 1000 ° on a 1 mm thick glass substrate by sputtering. Co., Ltd.) was applied by spin coating (1500 rpm: 30 seconds), allowed to stand at room temperature for 1 day, and then dried in a 150 ° C. oven for 3 hours to form a film having a thickness of about 0.1 μm. Forming a 5 μm layer,
This surface was subjected to plasma treatment, and then an information recording medium layer having a thickness of 6 μm was formed on the charge injection preventing layer in the same manner as in Example 1 to produce 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 10, it was confirmed that the information could be recorded similarly.

Further, a fluorine resin (trade name: CYTOP, Asahi Glass Co., Ltd.) is provided on the information recording layer of the information recording medium.
Co., Ltd.) in a 5% fluorine solution (1500 rpm)
m: 30 seconds), allowed to stand at room temperature for one day, and dried in a vacuum oven at 80 ° C. to form a charge holding layer having a thickness of about 0.5 μm. Produced. Next, when electrostatic information was recorded in the same manner as in Example 10, it was confirmed that the electrostatic information could be recorded in the same manner.

Further, even after the information recording medium was allowed to stand at room temperature for 20 days, the visible image was maintained, and the surface potential was reproduced by the surface voltmeter, indicating that the information was maintained.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view of an information recording medium according to the present invention, in which (a) is a schematic diagram before information recording, and (b) illustrates a state of information recording and reproduction on the information recording medium after information recording. FIG. 3C is a diagram showing another example of the information recording medium of the present invention.

FIG. 2 is a diagram for explaining an information recording method using a photoconductor.

[Explanation of symbols]

1 is a photoreceptor, 5 is a support, 7 is an electrode layer, 9 is a photoconductive layer,
Reference numeral 3 denotes an information recording medium, 11 denotes a resin, 12 denotes a liquid crystal phase, 13 denotes an electrode layer, 14 denotes a charge holding layer, 15 denotes a support, and 16 denotes a charge injection preventing layer.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G02F 1/13 505 G02F 1/1334 G03G 5/02

Claims (10)

(57) [Claims] 1. A photoconductor comprising a photoconductive layer provided on an electrode layer.
Exposure while applying voltage between both electrodes
An information recording medium that records and stores information as visible information.
Te, the information recording medium, Rutotomoni information recording layer made of a liquid crystal phase dispersed fixed acrylic or methacrylic resin is laminated on the electrode layer, the weight average molecular weight of acrylic resin or a methacrylic resin in said information recording layer is 1 10,000-1
100,000 and the total amount of resin and liquid crystal material
Information recording medium using the ratio of the liquid crystal is characterized by this <br/> and a 30 wt% to 60 wt% of. 2. A photoconductor comprising a photoconductive layer provided on an electrode layer.
Exposure while applying voltage between both electrodes
An information recording medium that records and stores information as visible information.
Te, the information recording medium, Rutotomoni information recording layer made of a liquid crystal phase dispersed fixed acrylic or methacrylic resin is laminated on the electrode layer, the weight average molecular weight of acrylic resin or a methacrylic resin in said information recording layer is 1 10,000-1
In 00000, and Ri der acid value is more than one thing, and the resin
30% by weight of liquid crystal is used based on the total amount of liquid crystal material
An information recording medium characterized in that the content is about 60% by weight . 3. A photoconductor in which a photoconductive layer is provided on an electrode layer.
Exposure while applying voltage between both electrodes
An information recording medium that records and stores information as visible information.
Te, the information recording medium, the information recording layer and the charge storage layer made of a liquid crystal phase dispersed fixed an acrylic resin or a methacrylic resin are sequentially stacked on the electrode layer Rutotomoni, the information recording
The weight average molecular weight of acrylic resin or a methacrylic resin in the layer all SANYO of 10,000 to 100,000, and the resin and the liquid
Use ratio of liquid crystal to total amount of crystal material is 30% by weight or more
An information recording medium characterized by being 60% by weight . 4. The information recording medium according to claim 1, wherein the liquid crystal phase is a nematic phase or a cholesteric phase at a use environment temperature. 5. The information recording layer according to claim 1, wherein the information recording layer is subjected to a heat treatment at a temperature higher than room temperature and lower than the isotropic phase transition temperature of the liquid crystal before recording the information. An information recording medium according to claim 1. 6. The information recording medium according to claim 1, wherein the resin has a glass transition temperature higher than a use environment temperature. 7. The information recording medium according to claim 1, wherein the information recording layer is laminated on the electrode layer via a charge injection preventing layer. 8. An information recording medium in which an information recording layer made of an acrylic resin or a methacrylic resin in which a liquid crystal phase is dispersed and fixed on an electrode layer, wherein the resin has a weight average molecular weight of 10,000 to 100,000 der is, and the resin and the liquid crystal material
The use ratio of the liquid crystal to the total amount is 30% by weight to 60% by weight.
% Of the information recording medium and the photoreceptor having a photoconductive layer provided on the electrode layer are opposed to each other, and the electrostatic information is recorded by exposing from the photoreceptor or the information recording medium side while applying a voltage between both electrodes. And recording and storing the electrostatic information as visible information, and reproducing the electrostatic information at an arbitrary time. 9. An information recording medium in which an information recording layer made of an acrylic resin or a methacryl resin in which a liquid crystal phase is dispersed and fixed on an electrode layer, wherein the resin has a weight average molecular weight of 10,000 to 100,000, der is, whether and an acid value of 2 or more of those
The ratio of liquid crystal used to the total amount of resin and liquid crystal material is
An information recording medium of 30% by weight to 60% by weight and a photoreceptor having a photoconductive layer provided on an electrode layer are arranged to face each other, and light is exposed from the photoreceptor or information recording medium side while applying a voltage between both electrodes. A method for recording and storing electrostatic information as visible information, and reproducing the information at an arbitrary time. 10. The method for recording and reproducing electrostatic information according to claim 9, wherein the visible information is reproduced by transmitted light or reflected light.