JPH08179256A - Information recording medium - Google Patents

Abstract

PURPOSE: To provide an information recording medium capable of controlling the driving voltage of liquid crystal through the control of the particle diameter of the liquid crystal, covering the driving voltage of the liquid crystal in a wide range and recording information of high quality by forming the information recording layer by film emulsion method. CONSTITUTION: The 1st information recording medium is an information recording medium provided with an information recording layer 11 on an electrode layer 13, the information recording layer is a coated and dried material of an oil-in-water type emulsion obtained by forcibly feeding the liquid crystal with a porous film into a water soluble resin solution and is a liquid crystal dispersed material (a) controlled in the particle diameter of the liquid crystal, and a 2nd information recording medium is the information recording medium provided successively with the electrode layer 13, a photoconductive layer 14, the information recording layer 11 and the electrode layer 13, an electrode of at least one of the electrode layers 13, 13' is transparent and the information recording layer 11 is the coated and dried material of the oil-in- water emulsion obtained by forcibly feeding the liquid crystal with the porous film into the water soluble resin solution and is the liquid crystal dispersed material controlled in the particle diameter of the liquid crystal (b, c).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information recording medium capable of obtaining electrostatic information recorded as a visible information by an exposure recording method when a voltage is applied, and more particularly to an information recording medium capable of controlling a liquid crystal driving voltage. .

[0002]

2. Description of the Related Art An optical sensor in which a photoconductive layer is laminated on an electrode and an information recording medium in which an information recording layer made of polymer dispersed liquid crystal is laminated on an electrode are arranged facing each other on the optical axis. Information recording / reproduction in which exposure is performed while applying voltage between electrode layers, the liquid crystal layer is oriented by the electric field formed by the optical sensor to record information, and when reproducing information, it is reproduced as visible information by transmitted light or reflected light. The method was previously filed as Japanese Patent Application No. 4-3394, Japanese Patent Application No. 4-24580, Japanese Patent Application No. 4-24722, and Japanese Patent Application No. 5-266646. This information recording / reproducing method makes it possible to visualize recorded information without using a deflector. In such an information recording layer, the unexposed portion becomes opaque due to the birefringence of the liquid crystal molecules, and the exposed portions become transparent because the liquid crystal molecules are aligned in the direction of the electric field. Done.

Generally, the voltage (driving voltage) required for aligning liquid crystal molecules in the direction of the electric field is considered to depend on the diameter of the liquid crystal domain. The smaller the liquid crystal domain, the more binding force the liquid crystal molecule receives from the outer wall (resin). Therefore, a high voltage is required to align the liquid crystal in the electric field direction.
Therefore, when a large liquid crystal domain and a small liquid crystal domain coexist in the polymer-dispersed liquid crystal, the transmittance changes gently with respect to the voltage change. Further, if the diameter of the liquid crystal domain is uniform, the transmittance changes sharply with respect to the voltage change.

Heretofore, as a method for forming an information recording layer using a polymer dispersed liquid crystal, the liquid crystal is mechanically dispersed in a resin solution by using a high-speed stirrer, or an ultrasonic homogenizer is used. It is formed by applying the dispersed dispersion liquid on the electrode layer. In the information recording layer manufactured by such a method, the particle size distribution of the liquid crystal domain is controlled and the liquid crystal drive voltage is controlled. However, there is a problem in that even if the information is exposed by being arranged so as to face the optical sensor, the information recording in which the highlight portion is skipped is performed depending on the applied voltage.

The ability to scatter incident light in the absence of applied voltage depends on the diameter of the liquid crystal sphere, which is related to the wavelength of light and the number of liquid crystal / resin interfaces. If the size is too large or too small, a sufficient light scattering state cannot be obtained. Therefore, in order to realize high contrast, low voltage driving and steepness at the same time in the information recording phase, it is necessary to make the diameter of the liquid crystal sphere uniform and to optimize the liquid crystal sphere. The diameter of is determined by the diameter of liquid crystal particles in the applied emulsion. Therefore, in order to control the liquid crystal particle diameter, it is necessary to control the diameter of the liquid crystal particles in the emulsion.

[0006]

DISCLOSURE OF THE INVENTION The present invention relates to an improvement of an information recording medium having a polymer dispersed liquid crystal as an information recording layer in which information is recorded using an optical sensor having a photoconductive layer laminated on electrodes. In particular, it is an object to provide an information recording medium capable of controlling a liquid crystal driving voltage and capable of recording high quality information.

[0007]

A first information recording medium of the present invention is an information recording medium in which an information recording layer is provided on an electrode layer, and the information recording layer is water-soluble through a porous film. It is a dried and applied product of an oil-in-water emulsion obtained by press-fitting liquid crystal into a liquid crystalline resin solution, and is also a liquid crystal dispersion having a controlled liquid crystal particle size.

A second information recording medium of the present invention is an electrode layer,
An information recording medium in which a photoconductive layer, an information recording layer, and an electrode layer are sequentially provided, and at least one electrode of the electrode layer is transparent, and the information recording layer is a water-soluble resin via a porous film. It is a dried and applied product of an oil-in-water emulsion obtained by press-fitting liquid crystal into a solution, and a liquid crystal dispersion in which the liquid crystal particle size is controlled.

FIG. 1A is a diagram for schematically explaining a cross section of a first information recording medium of the present invention, in which 3 is an information recording medium, 11 is an information recording layer, 13 is an electrode layer, Reference numeral 15 is a substrate.

The information recording layer 11 is composed of liquid crystal particles (droplets) dispersed in a matrix resin, and an aqueous resin solution is made to flow along one surface of a porous film having a large number of through holes. At the same time, a step of producing a oil-in-water type emulsion in which liquid crystal particles are dispersed by injecting liquid crystal into a resin aqueous solution with a predetermined pressure from the other surface of the film, and the obtained liquid crystal emulsion on the electrode phase 13. It is formed by coating and drying.

The matrix resin is a water-soluble or water-dispersible resin such as polyvinyl alcohol, gelatin, an acrylic acid copolymer and a water-soluble alkyd resin, and is preferably polyvinyl alcohol. Polyvinyl alcohol having a low saponification degree is preferably used, and since polyvinyl alcohol itself has surface activity, a good liquid crystal emulsion can be obtained without using other surface active agents.

Next, examples of liquid crystals include smectic liquid crystals, nematic liquid crystals, cholesteric liquid crystals, and mixtures thereof. As the liquid crystal, it is preferable to use a smectic liquid crystal from the viewpoint of so-called memory property that retains the orientation of the liquid crystal and permanently retains information. As the smectic liquid crystal, a liquid crystal substance exhibiting a smectic A phase such as a cyanobiphenyl type, a cyanoterphenyl type, a phenyl ester type, or a fluorine type having a long carbon chain at a terminal group of a substance exhibiting a liquid crystal property, or a ferroelectric liquid crystal is used. Examples thereof include a liquid crystal substance exhibiting a smectic C phase, a liquid crystal substance exhibiting smectic H, G, E, F and the like.
A nematic liquid crystal may be used, and the memory property can be improved by mixing with a smectic or cholesteric liquid crystal, and examples thereof include a Schiff base type, an azoxy type, an azo type, a benzoic acid phenyl ester type, and a phenyl cyclohexylate. Known nematic liquid crystals such as ester type, biphenyl type, terphenyl type, phenyl cyclohexane type, phenyl pyridine type, phenyl oxazine type, polycyclic ethane type, phenyl cyclohexene type, cyclohexyl pyrimidine type, phenyl type and tolan type can be used.

The liquid crystal may contain a dye in order to improve the contrast or the color tone. When a dichroic dye is added as a dye, it should be used not only as a scattering-transmissive display element but also as a display medium that switches in a light absorption (coloring) -transparent state by the guest-host effect of the dye. You can also

The content ratio of liquid crystal in the information recording layer is 3
It is 0% to 90% by weight, preferably 40% to 80% by weight. If the content of the liquid crystal is less than 30% by weight, the contrast is insufficient, and if it exceeds 90% by weight, the film is not formed well, which is not preferable.

The thickness of the information recording layer is 4 μm to 15 μm.
If the thickness is less than 4 μm, the contrast is insufficient, and if it exceeds 15 μm, the driving voltage becomes high.

Further, by making the light refractive index of the aligned liquid crystal and the light refractive index of the resin substantially the same, it is opaque due to light scattering when no electric field is applied, and the liquid crystal phase is aligned when an electric field is applied, The information recording section can be in a transparent state, and the deflector plate is not required even when reproducing information,
The optical system for reading can be simplified.

Next, a method of forming the information recording layer will be described. The liquid crystal emulsion for forming the information recording layer is obtained by using a so-called "membrane emulsification method", and is expected to be used in recent years for the production of pharmaceuticals, cosmetics, foods, etc. (Tadao Nakajima 1 other person, PHARM TECH JAPAN
Vol. 4, No. 10, (1988)).

In this membrane emulsification method, the size of the liquid crystal emulsion particles depends on the pore diameter of the porous membrane used. Therefore, by using a porous membrane having a narrow pore diameter distribution, an emulsion having a uniform particle diameter can be obtained. Is possible. The diameter of the liquid crystal dispersed particles in the emulsion is preferably in the range of 0.5 to 7 μm, and particularly preferably in the range of 1 to 5 μm.

The porous membrane has a uniform pore size,
It is necessary to maintain a reasonable mechanical strength, for example Na ₂
A porous glass produced by utilizing the phase separation phenomenon of OB ₂ O ₃ —SiO ₂ glass can be mentioned (see US Pat. No. 2,215,039). As a preferred example, a conceptual diagram of a liquid crystal emulsion production apparatus using a pipe-shaped porous glass is shown in FIG.

The emulsion tank (d) in the production apparatus is filled with a resin aqueous solution containing a surfactant as necessary, and this is pumped by a pump (e) to a valve (i) and a pressure system in a pipe of a porous membrane ( j) and circulate along the line leading to the needle valve (k). For the circulation pump (e), it is preferable to select a model having a low shearing force and a small pulsating flow so that the purified emulsion particles are not broken.

On the other hand, the liquid crystal tank (c) is pressurized by the pressure of nitrogen introduced from the nitrogen cylinder (b), and the liquid crystal whose pressure is adjusted by the valve (f) has an opening of a porous body on the inner surface. Are press-fitted into the open tubular body (a) and dispersed in the resin aqueous solution flowing in the tube into fine spherical particles. The pore size of the porous body used at this time is usually 0.1 to 1 μm, preferably 0.2 to 0.4 μm.
m.

The liquid crystal press-fitting pressure varies depending on the size of the apparatus, the type of liquid crystal, the micropore diameter of the porous material, the composition of the dispersion medium, etc., but is usually 1 to 10 kgf / cm ² , and preferably 1.5. Is about 4 kgf / cm ² .

When the resin aqueous solution to be added to the tank (d) interferes with emulsification due to its viscosity or the like, water is added to the tank (d) if necessary with a surfactant to prepare an emulsion. After that, the matrix resin may be dissolved or dispersed.

After the liquid crystal emulsion is produced, water may be removed and concentrated to make it suitable for coating. In addition, in order to improve the solubility and coating suitability of the matrix resin,
A water-soluble organic solvent such as ethanol or ethyl cellosolve may be added.

Liquid crystal particle dispersions are obtained in this manner. Liquid crystal particle dispersions having various liquid crystal particle sizes are prepared and then appropriately mixed and used according to the required driving voltage range.

In another preferred embodiment of the present invention, the liquid crystal emulsion obtained by the film emulsification method may be treated to produce microcapsules containing liquid crystal, and the microcapsule dispersion may be used as it is as a coating liquid, or After separating the microcapsules, the coating liquid may be used again. As a method for producing microcapsules, both a chemical production method and a physicochemical production method can be used.

As the chemical preparation method, there are an interfacial polymerization method using a synthetic reaction, an in situ polymerization method, and an in-liquid hardening coating method which causes a change in physical properties of a polymer. The interfacial polymerization method is a method in which a water-soluble monomer and an oil-soluble monomer are selected as two kinds of monomers that undergo a polycondensation or polyaddition reaction, and either one is dispersed and reacted at the interface. in situ
The u-polymerization method is a method in which a reactant (monomer and initiator) is supplied from one of the inside and the outside of the core material to cause the reaction on the surface of the capsule wall film.

As a physicochemical preparation method, a coacervation method utilizing phase separation, an interfacial precipitation method, a liquid concentration method,
In-liquid drying method and secondary emulsion method are available. A simple coacervation method in which phase separation is caused by a decrease in solubility or a complex coacervation method in which phase separation is caused by an electrical interaction can also be used.

The interfacial precipitation method is a method capable of encapsulation under mild conditions without violent reaction or abrupt pH change. For example, an emulsion in which a liquid crystal core material is dispersed is dissolved in a solvent solution of a hydrophobic polymer. It is a method of redispersing in a protective colloid aqueous solution after dispersing it in.

Next, a method of forming the information recording layer will be described. In order to form the information recording layer, the liquid crystal particle dispersion liquid is directly applied onto the electrode layer, or is applied onto the substrate by a usual applying method and dried to form a film, which is then transferred onto the electrode layer 13. It is formed. Examples of the coating method include blade coating, knife coating, rod coating, roll coating, gravure coating, bead coating, spray coating and screen printing. Further, in the case of pattern-wise coating, a method of adding a suitable thickening agent to a liquid crystal emulsion to increase the viscosity and performing metal screen printing without a mesh is preferable, and according to this method, a predetermined position is formed at a predetermined position. It is possible to form a liquid crystal / polymer composite film of a size, and it is economical without wasteful use of expensive liquid crystal.

When a curable matrix resin is used, it is advisable to use an appropriate curing means such as heat, ultraviolet rays or electron beams for curing. Further, the liquid crystal in the information recording layer has a spherical shape, but some of them may be united.

The electrode layer 13 is required to be transparent when reading the information recorded in the information recording layer with transmitted light, and the metal thin film conductive film has a specific resistance value of 10 ⁶ Ω · cm or less. Film, conductive film of inorganic metal oxide such as indium tin oxide,
It is an organic conductive film such as a quaternary ammonium salt. The electrode layer is formed by a method such as vapor deposition, sputtering, CVD, coating, plating, dipping and electrolytic polymerization. The film thickness needs to be changed depending on the electrical characteristics of the material forming the electrodes and the applied voltage at the time of recording information. For example, an ITO film has a thickness of about 100 to 3000 Å, and the entire surface between the information recording layer and Alternatively, it is formed according to the formation pattern of the information recording layer.

When the information recorded on the information recording layer is read by reflected light, the electrode layer may be made light reflective or the transparent electrode layer may be laminated with a light reflective layer. In order to make the electrode layer light-reflecting, a metal electrode such as aluminum may be used. As the light reflecting layer, for example, a dielectric mirror layer can be cited, and it is preferable to provide it on one side or on both sides of the electrode layer.

The substrate 15 may be either transparent or opaque depending on whether information is read by transmitted light or reflected light. The information recording medium may have a shape such as a card, a film, a tape, a disc, etc., but the support strongly supports the information recording medium, and when the information recording layer has supportability, No need to provide. The material and thickness of the support are not particularly limited, and include, for example, a flexible plastic film or glass,
Rigid bodies such as plastic sheets and cards are used. Specifically, when the information recording medium has a flexible film, tape, disc, or card shape, a flexible plastic film is used, and when strength is required, a rigid sheet or glass. Inorganic materials and the like are used.

When reproducing information with transmitted light, whether a layer having an antireflection effect is laminated on the substrate as necessary, or whether the transparent substrate is adjusted to a film thickness capable of exhibiting the antireflection effect. The antireflection property may be imparted by further combining the two.

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

The photosensor is formed by laminating an electrode layer and a photoconductive layer on a transparent substrate, and the photoconductive layer is a single layer system having a charge generating function and a charge transporting function corresponding to information light at the same time. And a laminated system in which a charge generation layer and a charge transport layer are sequentially laminated on an electrode layer. The photoconductive layer generally has a function of generating photocarriers (electrons and holes) in the irradiated portion when irradiated with light, and these carriers can move in the layer width. When present, the effect is significant.

The single-layer photoconductive layer is formed of an inorganic photoconductive substance or an organic photoconductive substance. Examples of the inorganic photoconductive substance include Se, Se—Te, ZnO, TiO ₂ , and S.
i, CdS, etc., for example, vapor deposition method, sputtering method, CVD
On the electrode layer by a method or the like alone or in a mixed system of 5 to 30 μ
m, preferably 20 to 30 μm. Further, the above-mentioned inorganic photoconductor as fine particles may be dispersed in an organic insulating resin such as a silicone resin, a polyester resin, a polycarbonate resin, a styrene-butadiene resin, a styrene resin, or a polyvinyl acetal resin to form a photoconductive layer, In this case, 0.1 to 10 parts by weight, preferably 1 to 5 parts by weight, of the photoconductive fine particles are dispersed in 1 part by weight of the resin.

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

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

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

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

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

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

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

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

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

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

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

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

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

In the optical sensor described in this publication, the electric field or the amount of electric charge applied to the information recording medium during light irradiation is amplified as the light is irradiated, and when the voltage is continuously applied even after the light irradiation is finished, It has the function of maintaining conductivity and continuously applying an electric field or an amount of charge to the information recording medium.

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

When information light is made incident from the light source 21 while applying a voltage by the pulse generator 23 between the electrodes 13 and 13 ', photo carriers generated in the photoconductive layer 14 at the portion where the light is made incident are generated on both electrodes. By the electric field formed by, the electric field moves to the interface on the information recording layer 11 side, the voltage is redistributed, the liquid crystal phase in the information recording layer 11 is aligned, and recording is performed according to the pattern of information light. In the figure, the photoconductor side is the positive electrode and the information recording medium side is the negative electrode, but it goes without saying that the polarity is set according to the discharge characteristics of the optical sensor.

When setting the applied voltage, since some liquid crystal materials operate at a low voltage, the voltage distributions of the optical sensor, the air gap, and the information recording medium are appropriately set and applied to the information recording layer. The voltage should be set in its operating voltage range. Information recording by this optical sensor is possible as planar analog recording, and since the liquid crystal phase can be aligned at the electrostatic charge level,
A high resolution similar to that of silver salt photography can be obtained, and the exposure pattern is retained as a visible image due to the orientation of the liquid crystal phase.

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

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

As shown in FIG. 4, when the electrostatic information recorded on the information recording medium is reproduced by transmitted light, the liquid crystal is oriented in the electric field direction in the information recording portion, so that the light A is transmitted. On the other hand, the light B is scattered at the portion where no information is recorded, and the contrast with the information recording portion can be obtained.
The information recorded by the orientation of the liquid crystal is visible information that can be visually read, but it can also be magnified and read by a projector, laser scanning, or CC.
Information can be read with high accuracy by reading using D, and scattered light can be prevented by using a Schlieren optical system as needed. Furthermore, as described above, it is possible to read by reflected light by making the electrode layer itself light reflective or by laminating a light reflective layer on the electrode layer.

Next, the second information recording medium of the present invention will be described. The second information recording medium is one in which a photoconductive layer is incorporated into the first information recording medium, and does not require an optical sensor or the like for recording information and can record information by itself. FIG. 1B is a diagram for schematically explaining the cross section, in which 3 is an information recording medium, 11 is an information recording layer, 13 and 13 'are electrode layers, 14 is a photoconductive layer, and 15 is a photoconductive layer.
Is the substrate.

Photoconductive layer 14 laminated on electrode 13 '
Is the same as the photoconductive layer in the above-described photosensor, and the information recording layer 11 described in the section of the first information recording medium is provided on the photoconductive layer as the first information recording medium. It is laminated in the same manner.

The electrode layers 13 and 13 'can employ the same material and forming method as those of the electrode layer in the above-mentioned first information recording medium, but are transparent when the recorded information is read by transmitted light. Is required, and when reading with reflected light, either one of the electrode layers may be made light reflective, or a light reflecting layer such as a dielectric mirror layer may be laminated on either one of the electrode layers. A substrate may be laminated on the electrode 13 on the information recording layer.

Next, in the second information recording medium, an intermediate layer 12 may be provided between the photoconductive layer 14 and the information recording layer 11 as shown in FIG. 1 (c). When the photoconductive layer is an organic photosensitive layer formed by using a solvent, the intermediate layer 12 may cause the liquid crystal in the information recording layer to be eluted due to the interaction depending on the solvent, or the information recording layer may be a photoconductive layer. The photoconductive material is eluted by the solvent for forming the information recording layer at the time of coating and forming it on the surface, and image unevenness occurs.

As such an intermediate layer, inorganic materials such as SiO ₂ , TiO ₂ , CeO ₂ , Al ₂ O ₃ , GeO ₂ , Si ₃ N ₄ , AlN,
TiN, MgF ₂ , ZnS or the like may be used and laminated by vapor deposition, sputtering, chemical vapor deposition (CVD) or the like. Further, an aqueous solution of polyvinyl alcohol, water-based polyurethane, water glass or the like may be used as a water-soluble resin having a low compatibility with an organic solvent, and the layers may be laminated by a spin coating method, a blade coating method, a roll coating method or the like. Further, a coatable fluororesin may be used, and in this case, it may be dissolved in a fluorine-based solvent and coated by a spin coating method, or laminated by a blade coating method, a roll coating method or the like. As the coatable fluorine resin, the fluorine resin described in Japanese Patent Application No. 4-24722 can be preferably used.

Further, in the case of an organic material which is formed into a film in a vacuum system, there is no fear of dissolving the photoconductive layer during the film formation. Of these, polyethylene, polypropylene, poly (monochlorotrifluoroethylene), polytetrafluoroethylene, etc. can be used as the material for forming the film by the vapor deposition method.
As a material for forming a film by the CVD method, polyparaxylene specifically described in Japanese Patent Application No. 4-24722 can be used.

Of the various materials mentioned above, it is particularly preferable to use polyvinyl alcohol, and when a material having a saponification degree of 97% or more and a polymerization degree of 1500 or more is used, the formation of the information recording layer is excellent. Can be something.

In forming the intermediate layer, it is necessary that the intermediate layer is not compatible with either the organic photoconductive layer forming material or the information recording layer forming material. Insulation of 10 ⁷ Ωcm or more is required because diffusion occurs and resolution deteriorates. If the thickness of the intermediate layer is too thin, not only image noise will occur due to interaction over time, but also a problem of penetration due to defects such as pinholes will occur during multilayer coating. Since the permeability varies depending on the solid content ratio of the material to be laminated and coated, the type of solvent, and the viscosity, the film thickness of the material to be laminated and coated may be appropriately set. The intermediate layer is required to be transparent, and in consideration of the voltage distribution applied to each layer, a material having a high dielectric constant as well as a thin film is preferable. If the photoconductive layer is formed of an inorganic material and there is no interaction such as liquid crystal seepage with the information recording layer, it is not necessary to provide the intermediate layer.

A method of recording information on the second information recording medium will be described with reference to FIG. First, the electrode 1
When the information light 18 is incident while applying a voltage between 3 and 13 ', the photocarriers generated in the photoconductive layer 14 in the portion where the light is incident move due to the electric field formed by both electrodes,
When the voltage is redistributed, the liquid crystal phase in the information recording layer is aligned, and recording according to the pattern of the information light 18 is performed. The voltage may be applied for a predetermined time while the information light 18 is being incident.

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

This information recording method enables planar analog recording and obtains high resolution because recording can be performed at the liquid crystal particle level, and the exposure pattern is retained as a visible image due to the orientation of the liquid crystal phase. To be done. Further, as the information input method, the same method as the method using the camera and the method described with the laser described in the section of the first information recording medium can be used. Further, the recording method using a laser can be similarly performed. Further, the spectral characteristics of the photoconductive layer do not need to be panchromatic, and may be sensitive to the wavelength of the laser light source.

The information recorded on the second information recording medium is
When reading with transmitted light, reproduction is performed with transmitted light from the information recording layer side similarly to the case of the first information recording medium shown in FIG. 4, and also when reading with reflected light.

Next, in the second information recording medium of the present invention, the intermediate layer 12 may be a laminate of an insulating light reflecting layer and a transparent insulating layer. As a result, the recording information can be read by making the reading light from the information recording layer side incident and reflecting it.

Examples of the insulating light reflecting layer include a dielectric mirror layer and a light-shielding film having light reflectivity. Examples of the dielectric mirror layer include those having a film thickness of λ / 4 and formed of, for example, a combination of silicon dioxide and titanium dioxide, or zinc sulfide and magnesium fluoride. As the light-shielding film having light reflectivity, for example, aluminum oxide, which is an insulating material, and germanium, which is a light-shielding material, are vapor-deposited at a rate of 50 Å / sec from different vapor deposition sources.
One example is germanium, which is vapor-deposited at a rate of 20 Å / sec and is simultaneously vapor-deposited to a film thickness of about 1 μm.

The transparent insulating layer has a problem that the insulating light-reflecting layer peels off when the information recording layer is directly formed on the insulating light-reflecting layer. The peeling-off is prevented, and the information recording layer 11 is preferably formed. It is provided for the purpose. The transparent insulating layer is
This is the same as the intermediate layer 12 described above.

In this information recording medium, the read light does not pass through the generally colored photoconductive layer when reading the information, so that the reproduced information can be noise-free.

In each of the first and second information recording media of the present invention, a primer layer is provided between the respective layers such as the electrode layer, the light reflection layer or the light reflection prevention layer, and the substrate to improve the adhesion. May be provided.

The primer layer is selected in consideration of the respective materials of the electrode layer, the light reflection layer or the light reflection prevention layer, and the substrate, and is made of an ionizing radiation curable resin such as a thermoplastic resin, a thermosetting resin, or an ultraviolet curable resin. Formed by applying resin, or
In the case of a combination of an inorganic material and an organic material, a known silane coupling agent, an organotitanium compound, an organometallic compound such as an organoaluminum compound may be used. Further, a primer layer may be provided between the electrode layer and the information recording layer, and the same material as described above can be used as the material thereof. In this case, the film thickness is 0.01 μm to 10 μm.
Range. Since the voltage applied to the information recording layer can be controlled by improving the adhesiveness and changing the film thickness, the recordable exposure range can be controlled.

Further, the first and second information recording media of the present invention are used by cutting them in the layer width direction into an appropriate size according to the mode of use. After cutting, a resin layer may be similarly laminated on the cut surface by a coating method or a laminating method to protect the cut surface.

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

[0079]

In the first and second information recording media of the present invention, the liquid crystal particle diameter can be controlled by forming the information recording layer by the film emulsification method, so that the drive voltage range of the liquid crystal is controlled. Therefore, the liquid crystal driving voltage can be covered in a wide range, and an information recording medium capable of high quality information recording can be obtained. Hereinafter, examples will be described. In the examples, “parts” means parts by weight and “%” means% by weight.

[0080]

【Example】

(Manufacturing Method 1 of Liquid Crystal Emulsion) Using the film emulsification system of the liquid crystal emulsion manufacturing apparatus (manufactured by Ise Chemical Industry Co., Ltd.) shown in FIG. 2, resin: liquid crystal (weight ratio) = 1: 2 under the following conditions.
A liquid crystal emulsion of was prepared.

Liquid crystal: Smectic liquid crystal (S-manufactured by BDH)
6 is 40 parts by weight and BDH E-31LV is 4 parts by weight mixed liquid crystal) Resin: Polyvinyl alcohol (Nippon Gosei Kagaku Kogyo Co., Ltd.)
KP-06 made by Kap-06, saponification rate%) 5% aqueous solution purified by methanol Porous glass: MPG (pore size 0.2 by Ise Chemical Industry Co., Ltd.)
7 μm) Pipe pressure: 2.35-2.45 Kgf / cm ² Pipe flow velocity: 0.8 m / sec As a result, a liquid crystal emulsion having a 50% average particle diameter of 1 μm was obtained.

(Production Method 2 of Liquid Crystal Emulsion) A liquid crystal of resin: liquid crystal (weight ratio) = 1: 2 was prepared in the same manner as in Production Method 1 of liquid crystal emulsion except that the operating conditions of the membrane emulsification system were changed to the following conditions. An emulsion was made.

Porous glass: MPG manufactured by Ise Chemical Industry Co., Ltd.
(Pore diameter 0.37 μm) Pressure inside the tube: 2.75 to 2.85 Kgf / cm ² As a result, a liquid crystal emulsion having a 50% average particle diameter of 2 μm was obtained.

(Example 1) On a cleaned glass substrate having a thickness of 1.1 mm, an indium tin oxide (IT
The O) film was formed by a sputtering method to obtain an electrode layer. On the electrode layer, a mixed emulsion of 50 parts by weight of the liquid crystal emulsion prepared by the above production method 1 and 50 parts by weight of the liquid crystal emulsion prepared by the production method 2 was applied with a blade coater, and then depressurized (100 mmHg) at 40 ° C. for 5 hours. ), And an information recording layer having a film thickness of 6 μm was formed to prepare a first information recording medium of the present invention.

After depositing a gold electrode on this information recording layer, a voltage of 600 V and a sawtooth wave of 0.1 second was applied between both electrodes, and a voltage (T ₁₀ ) showing 10% light transmittance thereof was applied. When measured, it was 200V. In addition, γ {(T ₉₀ −
T ₁₀ ) / film thickness} was 8 V / μm.

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

[0087]

Embedded image

Using 3 parts of a fluorenone azo pigment (manufactured by Nippon Senshoku Co., Ltd.) having 1 part, a polyester resin (byron 200, Byron 200), 1,4-dioxane: cyclohexanone = 1: 1 mixed solvent, A 100 g solution with a solid content of 2% was sufficiently dispersed with a paint shaker to form a coating solution, and ITO having a film thickness of 500 Å and a resistance value of 80 Ω / cm ²
The ITO side of the glass substrate having the film was applied using a blade coater with a gap of 2 mils, dried at 100 ° C. for 1 hour, and a charge generation layer having a film thickness of 0.3 μm was laminated.

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

[0090]

Embedded image

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

The obtained optical sensor and the information recording medium produced as described above are arranged so as to face each other with a PET film of 10 μm as a spacer, and incorporated in the recording apparatus of FIG.
With the optical sensor side as positive and the information recording medium side as negative, a normal camera was used as the exposure method, with a DC voltage of 750V applied, exposure f = 1.4, shutter speed 1/60 seconds, and outdoors. , I photographed the subject in the daytime. When the information recording medium was taken out after the exposure, an image having gradation was formed, and good reading was possible with light having a wavelength of 400 nm.

(Comparative Example 1) In the information recording medium of Example 1, the liquid crystal emulsion prepared by the above production method 1 was applied as the information recording layer by a blade coater and then depressurized (100 mmHg) at 40 ° C for 5 hours. It was dried underneath to form an information recording layer having a film thickness of 6 μm.

After a gold electrode was vapor-deposited on this information recording layer, a voltage of 500 V and a sawtooth wave of 0.1 second was applied between both electrodes, and a voltage (T ₁₀ ) showing 10% light transmittance thereof was applied. When measured, it was 200V. In addition, γ {(T ₉₀ −
T ₁₀ ) / film thickness} was 4 V / μm. Example 1 above
It can be seen that the driving voltage range is narrower than that of the information recording layer in FIG.

Further, when an image was taken in the same manner as in Example 1 except that the obtained information recording medium was used instead of the information recording medium in Example 1, an image in which the highlight part was blown out was obtained. Was given.

Example 2 On the photoconductive layer of the optical sensor prepared in Example 1, a fluororesin CYTOP (trade name; manufactured by Asahi Glass Co., Ltd., water absorption rate 0.01%, specific resistance 1 ×) was used.
10 ¹⁸ Ω · cm) is dissolved in perfluoro (2-butyltetrahydrofuran), and its 4.5% solution is applied with a spinner at 1500 rpm for 20 seconds, and the temperature is 80 ° C. for 1 hour.
After drying, an intermediate layer (transparent insulating layer) having a film thickness of 0.8 μm was formed.

Next, the liquid crystal emulsion mixture prepared in Example 1 was applied onto this transparent insulating layer in the same manner as in Example 1 and dried to form an information recording layer. ITO was used as an upper electrode on the obtained information recording layer by sputtering.
The second information recording medium of the present invention was manufactured by forming the film with a film thickness of 00Å.

The photoconductive layer side of the obtained information recording medium is positive,
With the information recording layer side as a negative and a normal camera as an exposure method, a DC voltage of 600 V was applied, exposure f = 1.4, shutter speed 1/60 seconds, and outdoors,
I took a picture of the subject in the daytime. When the information recording medium is taken out after the exposure, an image having gradation is formed.
Good reading was possible with light having a wavelength of 0 nm.

[Brief description of drawings]

FIG. 1 is a schematic view showing a cross section of an information recording medium, (a) is a schematic view showing a cross section of a first information recording medium of the present invention, and (b) and (c) are It is a schematic diagram which shows the cross section of the 2nd information recording medium of this invention.

FIG. 2 is a schematic explanatory view of a membrane emulsification device.

FIG. 3 is a schematic view of an information recording device using an optical sensor.

FIG. 4 is a diagram for explaining a method of reproducing recorded information on an information recording medium with transmitted light.

FIG. 5 is a diagram for explaining an information recording method on the second information recording medium of the present invention.

[Explanation of symbols]

1 is an optical sensor, 3 is an information recording medium, 11 is an information recording layer, 12 is an intermediate layer, 13 and 13 'are electrode layers, 14 is a photoconductive layer, 15 is a substrate, 18 is information light, 19 is a spacer,
21 is a light source, 22 is a shutter having a driving mechanism, and 23
Is a pulse generator (power source), 24 is a dark box, A is transmitted light, and B is scattered light.

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[Procedure amendment]

[Submission date] March 31, 1995

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Correction target item name] All drawings

[Correction method] Change

[Correction content]

FIG.

[Fig. 2]

[Figure 3]

[Figure 4]

[Figure 5]

Front page continuation (72) Inventor Masayuki Ando 1-1-1, Ichigaya-Kagacho, Shinjuku-ku, Tokyo Within Dai Nippon Printing Co., Ltd. (72) 1-1-1-1 Ichigaya-Kagacho, Shinjuku-ku, Tokyo No. 1 Dai Nippon Printing Co., Ltd.

Claims (2)

[Claims] 1. An information recording medium having an information recording layer provided on an electrode layer, wherein the information recording layer is obtained by press-fitting a liquid crystal into a water-soluble resin solution through a porous film to form oil-in-water droplets. An information recording medium, which is a dried product of a type emulsion and a liquid crystal dispersion having a controlled liquid crystal particle size. 2. An information recording medium in which an electrode layer, a photoconductive layer, an information recording layer, and an electrode layer are sequentially provided, and at least one electrode of the electrode layer is transparent, and the information recording layer comprises:
A dried and applied product of an oil-in-water emulsion obtained by press-fitting a liquid crystal into a water-soluble resin solution through a porous film, and a liquid crystal dispersion having a controlled liquid crystal particle size. Information recording medium.