JPH10219251A - Smectic liquid crystal composition for information recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject liquid crystal composition useful in an electrophotograph, etc., having high contrast and no granularity, and capable of suppressing noise generation and thereby enabling high-quality information recording through lowering applied voltage by incorporating a specific compound into an alkylcyanobiphenyl, etc. SOLUTION: This liquid crystal composition is obtained by incorporating preferably 0.5-20wt.% of one or more compounds selected from those shown by formulae I to IV (A1 , A2 , B1 and B2 are each phenylpyrimidine, biphenyl or phenylcyclohexane, etc.; R1 to R7 are each an alkyl or an alkoxy; (n) is 3-15; (m) is 0 or 1) in one or more compounds selected from 4-alkyl-4- cyanobiphenyls and 4-alkoxy-4-cyano-biphenyls.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to an information recording medium,
In particular, the present invention relates to a smectic liquid crystal composition for an information recording medium capable of obtaining, as visible information, electrostatic information recorded by an exposure recording method when a voltage is applied.

[0002]

2. Description of the Related Art Recently, an optical sensor in which a photoconductive layer is laminated on an electrode and an information recording medium in which an information recording layer composed of a liquid crystal-polymer composite is laminated on the electrode are arranged on the optical axis so as to face each other. Then, exposure is performed while applying a voltage between the two electrode layers, information is recorded by orienting the liquid crystal layer by an electric field formed by an optical sensor, and in reproducing information recording, reproduced as visible information by transmitted light or reflected light. Information recording media have been proposed (JP-A-5-165005, JP-A-6-165005).
-130347 gazette). Such an information recording medium can reproduce recorded information without using a polarizing plate, so that a high resolution can be obtained.

The information recording layer of this information recording medium has a structure in which an ultraviolet curable resin and a liquid crystal layer are dispersed. As a liquid crystal substance used for this, a smectic liquid crystal is preferable from the viewpoint of memory properties. A liquid crystal material exhibiting a smectic A phase such as a cyanobiphenyl-based, cyanoterphenyl-based, phenylester-based, or fluorine-based carbon chain having a long carbon chain, a liquid crystal material exhibiting a smectic C phase used as a ferroelectric liquid crystal, or smectic H; G,
It is stated that a liquid crystal material exhibiting E, F, or the like can be used. However, in reality, the carbon number of the alkyl side chain is 8 to 1
A liquid crystal composition comprising a mixture of 2-4-alkyl or 4-alkoxy-4-cyanobiphenyl is used.

However, the information recording medium using this kind of liquid crystal composition has a problem that recording contrast is low, and graininess (graininess) is generated, noise is generated at the time of reproducing information, and the quality of recorded information is low. was there. In addition, since the conventional liquid crystal composition has a high threshold voltage, the voltage applied to the information recording medium during information recording is high, and a high voltage is locally applied to each layer. Thus, there is a problem that the transmittance of the information recording layer becomes abnormally high, which causes noise.

[0005]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems, and an object of the present invention is to provide a high-contrast recorded information, a small graininess (roughness), and an applied voltage for recording information. It is an object of the present invention to provide a smectic liquid crystal composition for an information recording medium capable of suppressing noise by suppressing the occurrence of noise and enabling high-quality information recording.

[0006]

SUMMARY OF THE INVENTION The present invention provides a 4-alkyl-
At least one compound selected from 4-cyanobiphenyl or 4-alkoxy-4-cyanobiphenyl has the following general formulas (I) to (IV)

Embedded image (Where A ₁ and B ₁ are phenylpyrimidine, biphenyl, phenyl benzoic acid, phenylcyclohexane,
Phenyl = biphenylcarboxylic acid, biphenyl = benzoic acid, terphenyl or 1,5-diphenylpyrimidine,
R ₁ and R ₂ represent an alkyl group or an alkoxy group, and n represents 3 to
15 integers are shown. )

Embedded image (Where A ₂ and B ₂ are phenylpyrimidine, biphenyl, phenyl benzoic acid, phenylcyclohexane,
Phenyl = biphenylcarboxylic acid, biphenyl = benzoic acid, terphenyl or 1,5-diphenylpyrimidine,
R ₃ and R ₄ each represent an alkyl group or an alkoxy group. )

Embedded image (In the above formula, R ₅ and R _{6 each} represent an alkyl group or an alkoxy group, and m represents an integer of 0 or 1.)

Embedded image Wherein, in the above formula, R ₇ represents an alkyl group or an alkoxy group. At least one compound selected from the group consisting of 4-alkyl-4-cyanobiphenyl or Since at least one compound selected from 4-alkoxy-4-cyanobiphenyl contains at least one compound selected from the compounds represented by the general formula (I) or (II), Is a smectic liquid crystal composition for an information recording medium.

The above-mentioned 4-alkyl-4-cyanobiphenyl or 4-alkoxy-4-cyanobiphenyl is prepared by appropriately selecting the number of carbon atoms in the alkyl side chain or the alkoxy side chain of the compound according to the intended use temperature and the like. In general, it is preferable to select a compound having a side chain having 2 to 18 carbon atoms, particularly 8 to 12 carbon atoms, since a stable smectic liquid crystal phase can be easily obtained at around room temperature.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION 4-Alkyl-4- used in the present invention
As the cyanobiphenyl or 4-alkoxy-4-cyanobiphenyl, only one compound may be used, but in order to obtain a liquid crystal composition having a low melting point, a mixture of two or more compounds may be used. preferable. 4-Alkyl-4-cyanobiphenyl has an excellent effect on lowering the melting point, and 4-alkoxy-4-cyanobiphenyl has an excellent effect on stabilizing the smectic phase.
When 4-cyanobiphenyl, 4-alkoxy-4-cyanobiphenyl, and different kinds of compounds are mixed and used, a liquid crystal composition suitable for the purpose can be obtained relatively easily.
In particular, 4-alkoxy-4- having 9 to 10 carbon atoms in the side chain.
The number of carbon atoms in the side chain is 9 to 1 part by weight of cyanobiphenyl.
Mainly 4-alkyl-4-cyanobiphenyl of 10 to 4 parts by weight, and 4-alkoxy-4-cyanobiphenyl or 4-alkyl having a carbon number other than those described above.
It is preferable to use a small amount of -4-cyanobiphenyl (hereinafter, both compounds are referred to as “cyanobiphenyl compound”) because the smectic phase can have high stability and a low melting point. When the amount of the cyanobiphenyl compound having 11 or more carbon atoms in the side chain is increased, the nematic phase disappears in the liquid crystal phase series, and when used as an information recording medium, graininess (graininess) occurs. Since the amount at which this phenomenon occurs depends on the type and amount of the cyanobiphenyl compound, the amount of the mixture cannot be specified unequivocally. However, a cyanobiphenyl compound having 11 or more carbon atoms in the side chain is a mixture of the cyanobiphenyl compound. 50 of total quantity
% By weight or less.

On the other hand, when a large amount of a cyanobiphenyl compound having 8 or less carbon atoms in the side chain is mixed, the temperature range of the nematic phase is widened, and the contrast decreases when used as an information recording medium. The amount at which this phenomenon occurs also depends on the type and amount of the cyanobiphenyl compound, so the amount of the mixture cannot be specified unequivocally. However, a cyanobiphenyl compound having 8 or less carbon atoms in the side chain is a mixture of the cyanobiphenyl compound. It is preferable that the total amount be 60% by weight or less. The driving voltage can be reduced by adding a small amount of a cyanobiphenyl compound having 2 to 5 carbon atoms, for example, 1 to 10% by weight.

These cyanobiphenyl compounds are generally commercially available and easily available. For example, 4-alkyl-4-bromobiphenyl or 4-alkoxy-4-bromobiphenyl is reacted with copper cyanide. By doing so, the corresponding 4-alkyl-4-cyanobiphenyl or 4-alkoxy-4-cyanobiphenyl can be synthesized.

In the present invention, the above-mentioned cyanobiphenyl compound or a mixture thereof is added to the above-mentioned general formula (I) to (IV)
At least one of the compounds selected from the compounds represented by
Although seeds are added, the amount of each of these compounds is preferably in the range of 0.5 to 20% by weight.

The addition of the compounds of the above general formulas (I) and (II) imparts a strong torsional force to the smectic phase, disturbs the orientation of the liquid crystal, thereby improving the contrast and suppressing the roughness, and further reducing the driving voltage. Can be caused. The amount of this type of compound to be added may be appropriately selected in a total range of 0.1 to 20% by weight. If the amount is less than 0.1% by weight, the effect of improving the contrast and suppressing the roughness cannot be remarkably exhibited, and if the amount exceeds 20% by weight, the melting point tends to increase, which is not preferable. In order to obtain a particularly remarkable effect, these compounds are preferably added in an amount of 0.5 to 10, particularly preferably 1 to 5% by weight.

The groups A ₁ , A ₂ , B ₁ and B ₂ in the compounds of the general formulas (I) and (II) do not break the layer structure of the smectic phase of the cyanobiphenyl compound and are compatible with the biphenyl group. Any group may be used as long as it is excellent in the above-mentioned group, and particularly, a phenylpyrimidine group is preferable because of high compatibility.

The alkyl group and the alkoxy group of these compounds preferably have 1 to 15 carbon atoms, particularly preferably 5 to 12 carbon atoms, because of easy availability. Further, n in the general formula (I) may be 3 to 15, and particularly,
6 to 12 are preferred because they are easily available.

The compounds of the general formulas (I) and (II) have an asymmetric carbon and therefore have an optically active form. In the present invention, they can be used in a racemic form. It is particularly preferable to impart a twist between the layers to weaken the force acting between the layers, or to disturb the orientation to give a higher contrast.

More preferred compounds of the above formula (I) are 2,9-dimethyldecyl 1,10-bis [4- (5-octylpyrimidin-2-yl) benzoate], 2,9 -Dimethyldecyl 1,10-bis (4-octyloxybenzoate), 2,9-dimethyldecyl
1,10-bis [4- (4-cyanophenyl) benzoic acid ester], 2,9-dimethyldecyl 1,10-bis [4- (4-octyloxyphenyl) benzoic acid ester], 2,9-dimethyl Decyl 1,10-bis [4- (4-octylphenylcarbonyloxy) benzoate], 2,9-dimethyldecyl 1,10-bis [4- (4-hexylcyclohexanyl) benzoate], 2 , 9-dimethyldecyl 1,
Examples thereof include 10-bis [4- (4-octylphenylcarbonyloxy) benzoic acid ester].

These compounds are obtained by opening α, β-ψ, ω-diepoxyalkane with trimethylaluminum to obtain a primary alkanediol and then diethyl azodicarboxylate-triphenylphosphine [DEAD-P ( Ph) ₃ ], etc., in the presence of a dehydrating agent. In this case, when an optically active substance (for example, S, S form) is used as the diepoxide, the diol obtained above becomes an optically active form (for example, R, R form) whose absolute configuration is inverted from that of the diepoxide, and this is maintained. Thus, an optically active form of the ester (for example, R, R form) is obtained.

More preferred compounds of the general formula (II) are bis [4- (5-octylpyrimidin-2-yl) phenyl ester] 2-methylsuccinate and 2-methyl succinate. Bis [4- (4-octyloxyphenyl) succinate], Bis [4- (4-octyloxyphenyl) phenyl] methyl succinate] Bis [4- (4-hexylcyclohexyl) phenyl] methyl succinate] Etc. can be exemplified.

These compounds can be obtained by dehydrating and condensing 2-methylsuccinic acid and the corresponding phenol in the presence of a dehydrating agent such as dicyclohexylcarbodiimide in the presence of a catalyst such as N, N-dimethylaminopyridine. can get. In this case, when an optically active substance is used for the above-mentioned 2-methylsuccinic acid, the ester obtained above can be obtained as an optically active substance in which the absolute configuration of 2-methylsuccinic acid is maintained.

On the other hand, the compounds of the above general formulas (III) and (IV) have a function of lowering the viscosity of the liquid crystal, that is, a so-called thinner, and their addition contributes to lowering the driving voltage. The addition amount of this type of compound is preferably 0.5 to 30% by weight. When the content is less than 0.5% by weight, it is difficult to sufficiently exert the effect of improving the contrast and the effect of lowering the driving voltage. If the content is more than 30% by weight, the smectic phase tends to be unstable or the melting point tends to increase. Is not preferred. These compounds are in particular 0.5-0.5
It is advisable to add 20% by weight, more preferably 1 to 10% by weight. Further, the alkyl group and the alkoxy group of these compounds have 1 to 15 carbon atoms, particularly 1 to
It is preferable to use ten.

More preferable examples of the compound of the general formula (III) include 4- (trans-4-pentylcyclohexyl) -4-methylbiphenyl and 4- (trans-4
-Propylcyclohexyl) -4-ethylbiphenyl, 4-
(Trans-4-butylcyclohexyl) -4-ethylbiphenyl, 4- (trans-4-pentylcyclohexyl) -4-
Ethylbiphenyl, 4- (trans-4-hexylcyclohexyl) -4-ethylbiphenyl, 4- (trans-4-pentylcyclohexyl) -4-propylbiphenyl, 4- (trans-4-pentylcyclohexyl) -4-pentylbiphenyl , 4- (trans-4-pentylcyclohexyl) -4
-Methoxybiphenyl, 4- (trans-4-butylcyclohexyl) -4-methoxybiphenyl, 4- (trans-4-
Propylcyclohexyl) -4-methoxybiphenyl, 4-
(Trans-4-pentylcyclohexyl) -4-propyloxymethylbiphenyl and the like.

These compounds are prepared by reacting 4- (4-alkylcyclohexyl) -4-biphenyl with alkyl acid chloride in the presence of anhydrous aluminum chloride.
Alkylcyclohexyl) -4-alkanoylbiphenyl, which is reduced with hydrogen in the presence of palladium carbon, or 4- (4-alkylcyclohexyl) -4-formylbiphenyl is reduced with sodium borohydride
-(4-Alkylcyclohexyl) -4-hydroxymethylbiphenyl is obtained by reacting with thionyl chloride to form 4- (4-alkylcyclohexyl) -4-chloromethylbiphenyl and reacting with sodium alkoxide.

More preferred compounds of the general formula (IV) are, specifically, 4-hexylbenzoic acid 4
-Fluorophenyl ester, 4-octylbenzoic acid 4-
Examples include fluorophenyl ester, 4-hexyloxybenzoic acid 4-fluorophenyl ester, and the like. These compounds are obtained by dehydrating and condensing 4-alkyl or 4-alkoxybenzoic acid and 4-fluorophenol in the presence of a catalyst such as N, N-dimethylaminopyridine in the presence of dicyclohexylcarbodiimide or the like.

The compounds of the above general formulas (I) to (IV) may be added alone, respectively,
In order to achieve good granularity, low driving voltage and obtain good images, the compound of the general formula (III) and / or (IV) is added to the compound of the general formula (I) and / or (II). It is preferable to use them in combination. The amount of addition in this case may be appropriately selected within the above-mentioned range. In addition, in the liquid crystal composition of the present invention, in addition to these compounds, a liquid crystal compound such as 4-alkyl-4-cyanoterphenyl or a non-liquid crystal compound in a range that does not destroy the liquid crystal phase can be added. .

An information recording medium in which the liquid crystal composition of the present invention is used and an information recording device incorporating the same are shown below.

FIG. 1 shows an example of an information recording system.
It is the figure which showed the cross section typically. In the figure, 1 is an information recording layer, 2 is a photoconductive layer, 3 and 3 are electrode layers, and 4 and 4 are substrates. As shown in this figure, on a substrate 4, an electrode layer 3, an information recording layer 1, a photoconductive layer 2, an electrode layer 3, and a substrate 4 are sequentially laminated. Here, an information recording medium is constituted by the information recording layer 1, the electrode layer 3, and the substrate 4, and an optical sensor is constituted by the photoconductive layer 2, the electrode layer 3, and the substrate 4.

The substrates 4 and 4 strongly support an information recording medium having a shape such as a card, a film, a tape, and a disk. For example, a flexible plastic film, glass, a plastic sheet, A rigid body such as a card is used.

The electrode layers 3 and 3 are made of a metal thin film conductive film having a specific resistance of 10 ⁶ Ω · cm or less, an inorganic metal oxide conductive film such as indium tin oxide, an organic conductive film such as a quaternary ammonium salt, or the like. Can be The electrode layer 3 is formed by vapor deposition, sputtering, CVD, coating, plating, or the like on the entire surface between the information recording layers or according to the formation pattern of the information recording layers.
It is formed by a method such as dipping or electrolytic polymerization.

The information recording layer 1 is generally made of polymer dispersed liquid crystal having a structure in which resin particles are filled in a liquid crystal phase.

As the liquid crystal material, the above-mentioned smectic liquid crystal composition is used.

The resin particles are an ultraviolet-curable resin,
Monomers or oligomers that are compatible with the smectic liquid crystal composition of the present invention at room temperature or under heating, or compatible with a common solvent, such as acrylate, methacrylate, or dipentane Erythritol hexaacrylate, trimethylolpropane triacrylate, polyethylene glycol diacrylate, polypropylene glycol diacrylate,
Polyfunctional monomers such as isocyanuric acid (ethylene oxide modified) triacrylate, dipentaerythritol pentaacrylate, dipentaerythritol tetraacrylate, neopentyl glycol diacrylate, hexanediol diacrylate, etc. or polyfunctional urethane, ester oligomer, nonylphenol modified Acrylate, N-vinyl-2-pyrrolidone, 2-hydroxy-
Monofunctional monomers or oligomers such as 3-phenoxypropyl acrylate can be used. Further, a monomer represented by the following general formula (V) or (VI) can also be used.

Embedded image (In the above formula, at least one of R _{1 to} R ₆ is -COCH =
CH ₂ group, the remainder represents a hydrogen atom. )

The above resin forming material and liquid crystal composition, and 2
-Hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexylphenyl ketone, 1-
Photocuring agents such as (4-isopropylphenyl) -2-hydroxy-2-methylpropan-1-one and benzyldimethylketal, halogenated hydrocarbon solvents such as xylene, cyclohexanone, and chloroform; methylcellosolve; Alcohol derivative solvent, dissolved or dispersed in a solvent having a relatively low evaporation rate, such as an ether solvent such as dioxane, and coated on the electrode layer 3 by a coating method such as a plate coater, a roll coater, or a spin coater; It is formed by curing the resin forming material by light or heat. In this case, the liquid crystal composition is 10 to 90
%, Preferably 40 to 80% by weight. Further, in order to maintain wettability to the electrode layer 3 and form a coating on the surface of the information recording layer 1 to prevent elution of the liquid crystal composition, the information recording layer 1 is provided with N- (n-propyl) -N- ( β-acryloxyethyl) -perfluorooctylsulfonic acid amide, N- (n-propyl) -N- (β-methacryloxyethyl) -perfluorooctylsulfonic acid amide, a fluorosurfactant such as perfluorooctanesulfonic acid, It is advisable to add 0.1 to 20% by weight to the total amount of the liquid crystal composition and the resin forming material.

In general, the information recording layer 1 is preferably thinned to increase the sensitivity, and thickened to increase the contrast, so that the contrast ratio as well as the sensitivity is excellent. It is preferable that the film has a thickness of 1 to 30 μm.

On the other hand, the photoconductive layer 2 is a conductive layer in which photocarriers (electrons and holes) are generated at the irradiated portion when light is irradiated, and the carriers can move in the layer width. Any of a single layer system having both a charge generation function and a charge transport function in response to light and a laminate system in which a charge generation layer and a charge transport layer are sequentially laminated on an electrode can be used.

The single-layer conductive layer is formed by depositing an inorganic photoconductor such as selenium alone, selenium tellurium, zinc oxide, titanium oxide, silicon, cadmium sulfide, etc. by a vapor deposition method, a sputtering method or a CV method.
According to the method D, the inorganic photoconductor or the poly-N-ethylenically unsaturated substituted carbazoles or the poly-N-ethylenically unsaturated substituted phenothiazines may be laminated on the electrode layer in a thickness of 5 to 30 μm. High molecular photoconductive substances or low molecular weight photoconductive substances such as oxadiazoles, triphenylmethane derivatives, hydrazone derivatives, butadiene derivatives and stilbene derivatives substituted with alkylaminophenyl groups, etc. 0.1 for electrical insulating resin such as resin and polycarbonate resin
10 to 10 parts by weight, using an organic solvent such as dichloroethane, trichloroethane, chlorobenzene, or tetrahydrofuran, using a blade coating method, a dipping method, a spinner coating method, or the like to obtain 5 to 30 μm.
It is produced by forming a film on the electrode layer with a thickness of m.

As the laminated conductive layer, a charge generation layer in which selentellur, silicon doped with sulfur, oxygen, or the like is deposited to a thickness of 0.05 to 1 μm by a vapor deposition method, a sputtering method, a CVD method, or the like, and Selenium, arsenic selenium compound (A
s ₂ Se ₃ ), 10 to 50 μm of silicon or the like doped with methane or the like.
An inorganic photoconductive layer formed by laminating a charge transport layer to a thickness of m and a charge generation material such as a fluorene azo pigment, a monoazo pigment, a bisazo pigment, or a pyrrole pigment are coated with a silicone resin, styrene-butadiene copolymer. Dispersed in binder such as coalescing resin, epoxy resin, acrylic resin, etc.
A charge generation layer formed as a film having a thickness of about 1 μm, and a charge transporting substance such as a hydrazone compound, a pyrazoline compound, a carbazole compound, an oxazole compound, or a triazole compound dispersed in a binder such as the resin;
An organic material-based photoconductive layer having a charge transport layer formed to a thickness of m is suitable.

The photoconductive layer 2 has a sustained conductivity imparting agent, such as an arylmethane dye or a leuco dye, having a function of enhancing the sustained conductivity, a base current regulating action, a base current stabilizing action, or a light induced action. Substituted benzene having a current amplifying action, etc., an electron accepting substance such as substituted naphthalene or benzoquinone or a sensitizing dye such as a triphenylmethane dye or a pyrylium salt dye, a phenol-based, phosphorus-based or sulfur-based antioxidant, salicylic acid-based, A benzotriazole-based or cyanoacrylate-based ultraviolet absorber, a hindered amine-based light stabilizer, or the like can be added.

Further, the photoconductive layer 2 is provided between the photoconductive layer 2 and the electrode layer 3 to amplify a current generated by photo-induced in the photoconductive layer and to control the charge carrier injection property from the electrode to the photoconductive layer. In order to reduce the noise, unevenness, etc. of the information recorded on the information recording medium by adjusting the voltage substantially applied to the information recording medium or by making the charge carrier injection property from the electrode to the photoconductive layer uniform. Can be provided. This photo-induced current amplification layer is made of silicone resin, polycarbonate resin, vinyl formal resin, vinyl acetal resin, vinyl butyral resin, or the like.
It is produced by forming a film to a thickness of from 0.5 to 5 μm, into which the above-mentioned electron accepting substance, photoconductive substance and the like can be added.

The photoconductive layer 2 produced as described above,
The optical sensor composed of the electrode layer 3 and the substrate 4 is 100 μm or less, preferably 3 to 30 μm, with respect to the information recording medium composed of the information recording layer 1, the electrode layer 3 and the substrate 4 manufactured as described above. Spacer 5 formed by laminating a film of polystyrene, polyimide, polyethylene, etc., or aluminum, selenium, tellurium, gold, platinum, etc.
Or, fluorine-based resin, water-soluble resin, water glass, silica,
It is disposed to face through a dielectric layer 5 formed by laminating titania, selenium oxide, alumina, and the like.
The information recording system is constructed by connecting 3 to a voltage source.

FIG. 2 is a diagram schematically showing a cross section of another example of the information recording system, that is, one in which the information recording layer and the photoconductive layer are integrated. In the figure,
11 is an information recording layer, 12 is a photoconductive layer, 13 and 13 are electrode layers, and 14 is a substrate. This information recording system is produced by laminating the information recording layer 11 and the electrode layer 13 on the substrate 14, the electrode layer 13, and the photoconductive layer 12 formed by the above method, in the same manner as described above. You. In this case, between the information recording layer 11 and the photoconductive layer 12, in order to prevent the elution of the liquid crystal in the information recording layer by the solvent of the photoconductive layer and the unevenness of the image caused by the elution of the photoconductive material by the solvent of the information recording layer. A film made of inorganic material such as silicon oxide, titanium oxide, aluminum oxide, water glass, or organic material such as polyvinyl alcohol, polyurethane, polyethylene, etc., having a thickness of 0.01 to 1.5 μm and having an insulating property of 10 7 Ωcm or more. It is preferable to provide an intermediate layer (not shown) consisting of Further, between the information recording layer 11 and the photoconductive layer 12 of this information recording system, an insulating light reflecting layer such as a dielectric mirror layer or a light shielding film and a transparent insulating layer made of the same material as the above-mentioned intermediate layer (FIG. (Not shown) can be read by inputting read light from the information recording layer 11 side and reading the reflected light. Next, operation modes of these information recording systems will be described.

When information light is incident from the optical sensor side while a voltage is applied between the two electrode layers 3, 3, 13 or 13 by a pulse generator or the like, the photoconductive layer 2 or 12 in the portion where the light is incident is applied. The generated optical carrier moves to the interface on the information recording layer 1 or 11 side by the electric field formed by the two electrode layers, the voltage is redistributed, and the smectic liquid crystal phase in the information recording layer 1 or 11 is oriented. Recording according to the pattern of the information light is performed in the form of the orientation of the liquid crystal phase.

As a form of the information recording system, there are a method using a camera and a recording method using a laser. As a method using a camera, this information recording medium is used as a recording member instead of a photographic film used in a normal camera. In addition, the optical information is separated into R, G, and B light components by a prism and a color filter, extracted as parallel light, and one frame is formed by three information recording media for each of R, G, and B, or 1
By recording the R, G, and B images on different portions of each information recording medium to form one frame, color photographing can also be performed.

In a recording method using a laser, a laser exposure corresponding to an image signal, a character signal, a code signal, and a line drawing signal is performed by scanning. For analog recording such as an image, the light intensity of the laser is modulated. Do
Digital recording such as characters, codes, and line drawings can be performed by ON-OFF control of laser light.

The exposure information recorded on the information recording medium can be reproduced by transmitted light. That is, the portion where the light recorded by the information recording section is incident is transmitted because the smectic liquid crystal phase is oriented in the direction of the electric field, whereas the light is transmitted at the portion where information is not recorded. The light is scattered, the contrast is obtained in the information recording unit, and the image is visualized. Further, reading may be performed by reflected light using light reflection.

As described above, the information recorded by the orientation of the liquid crystal phase is visible information that can be visually read, but can also be read by enlarging it with a projector, and can be read by laser scanning or CCD. Information can be read with accuracy.

In the above information recording medium, the recording by the information exposure is visualized by the orientation of the liquid crystal. By using the smectic liquid crystal composition as the liquid crystal, the information is once oriented and the visualized information is not erased. In addition, memory properties can be provided. Further, when the memory is heated to a high temperature near the isotropic phase transition, the memory can be erased, so that it can be used for information recording again.

In the present invention, since this smectic liquid crystal composition is used by adding at least one of the compounds of the above general formulas (I) to (IV) to the cyanobiphenyl compound, the granularity (roughness) is good. In addition, it is possible to manufacture an information recording medium capable of high-quality information recording by driving with a high contrast and a relatively low voltage.

[0048]

EXAMPLES Examples 1 to 16 and Comparative Examples 1 and 2 (Preparation of liquid crystal composition) 4-n-propyl-4-cyanobiphenyl (compound number; A-1), 4-n-nonyl-4-cyano Biphenyl (compound number; A-2), 4-n-decyl-4-cyanobiphenyl (compound number; A-3), 4-n-dodecyl-4-cyanobiphenyl (compound number; A-4) and 4- 4- such as n-nonyloxy-4-cyanobiphenyl (compound number; A-5)
Alkyl-4-cyanobiphenyl or 4-alkoxy-4-
Cyanobiphenyl has a compound of the general formula (I) (S,
S) -2,9-dimethyldecyl 1,10-bis [4- (5-octylpyrimidin-2-yl) benzoate] (compound number; I-1), a compound of the general formula (II) ( R) -2-
Bis [4- (5-octylpyrimidine-2) methyl succinate
-Yl) phenyl ester] (compound number; II-1), 4- (trans-4-butylcyclohexyl) -4-methoxymethylbiphenyl (compound number; III-1), which is a compound of the general formula (III) -(Trans-4-pentylcyclohexyl) -4-ethylbiphenyl (compound number; III-
2) 4-hexylbenzoic acid 4-fluorophenyl ester (compound number; IV-1) which is a compound of the general formula (IV);
One or more compounds of other compounds, 4-pentyl-4-cyano-terphenyl (compound number; V-1), were added and mixed in the proportions shown in Table 1 to prepare a liquid crystal composition.

[0049]

[Table 1]

(Evaluation of Composition) The melting point of the liquid crystal composition prepared above was measured by a differential scanning calorimeter (DSC), the phase transition temperature at the time of cooling was observed by a polarizing microscope, and the double concentric rotational viscometer was used. 4 at a shear rate of 40 s ^-1
The viscosity at 0 ° C. (mPas) was measured. In addition, ITO
2 with rubbing treatment having film and polyimide alignment film
In a 3 μm thick cell composed of two glass plates, the liquid crystal composition is aligned in parallel with the smectic A phase, an electric field is applied at room temperature, and the change in the alignment of the liquid crystal is determined by the change in the amount of transmitted light by a polarizing microscope. Observation was performed, and the applied electric field (MV / m) when the transmitted light amount was 10% or less was measured as a DC applied electric field, with the transmitted light amount being 100% or less when no electric field was applied. Table 2 shows the results.

[0051]

[Table 2]

From these results, it can be seen that the liquid crystal composition of the present invention causes a change in the layer structure at a low applied voltage, so that the driving voltage can be lowered. The melting point, viscosity is relatively low, there to a relatively high temperature S _A phase, also seen preferable for the information recording medium.

Reference Example ( Preparation of First Information Recording Medium) Thoroughly cleaned 1.1 m thick
An indium tin oxide (ITO) film having a thickness of 100 nm was formed on a glass substrate having a thickness of 100 nm by a sputtering method to obtain an electrode layer of 80 Ω / □.

A solution of a bisazo pigment, DPDD-3 (manufactured by Dainichi Seika Kogyo Co., Ltd.) as a charge generating agent was applied on the electrode layer as a coating solution, coated with a blade coater, dried at 100 ° C. for 1 hour and dried at 300 nm. The charge generation layer was laminated. A hydrazone-based solution DPD as a charge transport agent is provided on the charge generation layer.
After applying T-3 (manufactured by Dainichi Seika Kogyo Co., Ltd.) using a spinner, it was dried at 80 ° C. for 2 hours to obtain a photoconductive layer having a thickness of 10 μm comprising a charge generation layer and a charge transport layer.

Further, 5 g of polyvinyl alcohol was dissolved in 95 g of pure water, and the solution was applied on the photoconductive layer with a spinner.
After drying at 80 ° C. for 1 hour, an intermediate layer having a thickness of 0.6 mm was formed. At this time, the film surface was good without eroding the photoconductive layer.

Next, for the liquid crystal compositions of Examples 1 to 16, 5.5 parts of the liquid crystal compositions and 4.5 parts of an ultraviolet curable resin (trade name: D-310, manufactured by Nippon Kayaku Co., Ltd.) 0.22 parts of a photocuring initiator (2-hydroxy-2-methyl-1-phenylpropan-1-one) and 0.1 part of a surfactant (trade name: Florard FC-430, manufactured by Sumitomo 3M). After adjusting the solid content to 50% by weight with xylene, and coating the above intermediate layer with a spinner, it was kept at 49 ° C. and irradiated with 500 mJ / cm ² of ultraviolet light to form an information recording layer.

The information recording layer cut surface obtained using the liquid crystal composition of Example 1 was extracted with liquid crystal using hot methanol, dried, and then scanned with a scanning electron microscope (Hitachi Seisakusho; S- When the internal structure was observed at a magnification of 10,000 according to (800), the surface of the layer was covered with resin, and the inside of the layer was filled with fine resin particles having a diameter on the order of submicrons.

On this information recording layer, an indium tin oxide (ITO) film having a thickness of 100 nm was formed by a sputtering method.
An electrode layer of 0Ω / □ was formed to obtain an information recording medium.

(Evaluation of the first information recording medium) The information recording medium obtained above was subjected to no voltage application,
The transmittance of light at 500 nm at room temperature was measured using an ultraviolet spectrophotometer. This is shown in Table 3 as T500.
The smaller the T500, the higher the contrast. Also, using this information recording medium, 0.1
In a second, the applied voltage is increased from 0 V to 500 V, and a change in the transmitted light amount at 500 nm at this time is measured. Is shown in Table 3 as V10. Note that the smaller V10 is, the lower the driving voltage is.

[0060]

[Table 3]

From the results, it can be seen that by using the liquid crystal composition of the present invention, information can be recorded with a high contrast and a low driving voltage.

Further, the above information recording medium was projected and exposed to gray scale for 33 msec from the photoconductive layer side, and a voltage of 350 V and 40 msec was applied between both electrodes. It was found that the transmittance of the information recording layer was changed according to the transmittance of the gray scale in any of the liquid crystal compositions using any of the liquid crystal compositions, and it was found that the information was recorded.

Further, the image was read with 488 nm light, A / D converted, and reproduced at 256 gradations.
Image recording of any of the liquid crystal compositions using 0.0 was achieved.
It was recorded without local noise from 1 lux sec.

(Preparation of Second Information Recording Medium) An indium tin oxide (ITO) film having a thickness of 100 nm was formed on a sufficiently cleaned 1.1 mm thick glass substrate by a sputtering method.
An electrode layer of 80Ω / □ was obtained. Using the liquid crystal composition of Example 1, an information recording layer coating solution having the same composition as above was applied and cured on the electrode to form an information recording layer, and an information recording medium was obtained. The liquid crystal was extracted from the cut surface of the obtained information recording layer using hexane, and the liquid crystal was extracted and dried. After that, the internal structure was observed at 10,000 times with a scanning electron microscope (S-800, manufactured by Hitachi, Ltd.). Similarly to the above, the surface of the layer was covered with resin, and the inside of the layer was filled with fine resin particles having a diameter on the order of submicrons.

Next, an ITO film having a thickness of 100 nm was formed on a sufficiently cleaned glass substrate having a thickness of 1.1 mm by a sputtering method to obtain an electrode layer of 80 Ω / □. Form a photoconductive layer by the same method as used,
Light sensor was obtained.

(Evaluation of Second Information Recording Medium) Next, the obtained optical sensor and the information recording medium produced above were
A 10 μm polyethylene terephthalate film was placed facing and incorporated as a spacer, a gray scale was projected and exposed from the optical sensor side for 33 msec, and a voltage of 650 V, 40 msec was applied between both electrodes. After the exposure, the information recording medium was observed, and it was found that the transmittance of the information recording layer changed according to the transmittance of the gray scale, and that the information was recorded.

The image was read with 488 nm light, A / D converted, and reproduced at 256 gradations. The image was recorded from 0.01 lux sec. Without local noise.

Comparative Reference Example (Comparative Evaluation of First Information Recording Medium) Except for using 5.5 parts of each of the liquid crystal compositions of Comparative Examples 1 and 2, the same method as in the preparation of the first information recording medium was used. As a result, an information recording medium was produced.

After exposing the information recording medium to the gray scale for 33 msec from the photoconductive layer side and applying a voltage of 400 V and 40 msec between both electrodes, the information recording medium was observed. Also in the case of using the liquid crystal composition, the transmittance of the information recording layer changed according to the transmittance of the gray scale, and it was found that the information was recorded.

The image was read with light of 488 nm, A / D converted, and reproduced at 256 gradations. The image was recorded from 0.01 lux sec. Was observed.

(Comparison evaluation of the second information recording medium) An information recording medium was produced in exactly the same manner as in the production of the second information recording medium, except that 5.5 parts of the liquid crystal composition of Comparative Example 1 was used. Then, it was incorporated into a recording device.

To this recording apparatus, a gray scale was projected and exposed from the photoconductive layer side for 33 msec.
After applying a voltage of 00 V for 40 msec, the information recording medium was observed. As a result, it was found that the transmittance of the information recording layer changed according to the transmittance of the gray scale, and that the information was recorded.

The image was read with light of 488 nm, A / D converted and reproduced at 256 gradations. The image was recorded from 0.01 lux sec, but local noise was observed. .

[0074]

The smectic liquid crystal composition for an information recording medium of the present invention has high contrast, has no graininess (roughness), and suppresses the generation of noise by reducing the applied voltage at the time of information recording. This makes it possible to record high-quality information, and is extremely useful as an information recording medium for electrophotography and the like.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a cross section of an example of an information recording system using a liquid crystal composition of the present invention.

FIG. 2 is a schematic view showing a cross section of another example of the information recording system using the liquid crystal composition of the present invention.

[Description of Signs] 1 information recording layer 2 photoconductive layer 3, 3 electrode layer 4, 4 substrate 11 information recording layer 12 photoconductive layer 13, 13 electrode layer 14 substrate

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI G02F 1/13 500 G02F 1/13 500

Claims (2)

[Claims] 1. At least one compound selected from 4-alkyl-4-cyanobiphenyl or 4-alkoxy-4-cyanobiphenyl has one of the following general formulas (I) to (I)
A smectic liquid crystal composition for an information recording medium, comprising at least one compound selected from the compounds represented by V). General formula (I); (Where A ₁ and B ₁ are phenylpyrimidine, biphenyl, phenyl benzoic acid, phenylcyclohexane,
Phenyl = biphenylcarboxylic acid, biphenyl = benzoic acid, terphenyl or 1,5-diphenylpyrimidine,
R ₁ and R ₂ represent an alkyl group or an alkoxy group, and n represents 3 to
15 integers are shown. ) General formula (II); (Where A ₂ and B ₂ are phenylpyrimidine, biphenyl, phenyl benzoic acid, phenylcyclohexane,
Phenyl = biphenylcarboxylic acid, biphenyl = benzoic acid, terphenyl or 1,5-diphenylpyrimidine,
R ₃ and R ₄ each represent an alkyl group or an alkoxy group. ) General formula (III); (In the above formula, R ₅ and R _{6 each} represent an alkyl group or an alkoxy group, and m represents an integer of 0 or 1.) General formula (IV); (In the above formula, R ₇ represents an alkyl group or an alkoxy group.) 2. The method according to claim 1, wherein at least one compound selected from 4-alkyl-4-cyanobiphenyl or 4-alkoxy-4-cyanobiphenyl comprises a compound represented by formula (I) or (II) A smectic liquid crystal composition for an information recording medium, comprising at least one selected compound.