JPH0658507B2 - Optical element - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel optical element utilizing the change in alignment of liquid crystal due to light. More specifically, the present invention has a β-keto acid polymer thin film that undergoes a reversible structural change by light and heat, and this action causes a change in the orientation of the liquid crystal layer, which is used to provide information. The present invention relates to an optical element for recording temporarily or permanently.

[0002]

2. Description of the Related Art Recording elements using liquid crystals are known to store information by utilizing an electric effect and one for storing information by utilizing an effect of light. The former is mainly used for display. The latter is an example applied to optical recording. By the way, in a liquid crystal display in which information is written by utilizing an electric effect, the information disappears when the power supply is stopped. Therefore, in order to permanently store the information, special measures must be added. Since a patterned electrode is used, the resolution is low and it is unsuitable as a large-capacity recording element. On the other hand, in the case of storing information by using the action of light and reversibly erasing the information by the action of light of another wavelength,
Although it can be applied to high-density optical recording, it requires two kinds of light for writing and erasing, and thus it is inevitable that the apparatus becomes complicated. In addition, a compound in which a compound whose structure is changed photochemically is mixed and which undergoes a phase change by the action of light exhibits excellent resolution during the first period of inputting information, but the liquid crystal flows, so that the time The resolution tends to decrease remarkably with the passage of time. For example, a photochromic cholesteric liquid crystal obtained by dissolving chiral azobenzene in a nematic liquid crystal changes to an isotropic phase by the action of ultraviolet rays, and this can be used to record information, but with the passage of time The liquid crystal flows and the recorded image becomes unclear. (See Proceedings of 52nd Annual Meeting of the Chemical Society of Japan, 1986).

[0003]

DISCLOSURE OF THE INVENTION The present invention provides an optical element utilizing the change in alignment of liquid crystal due to light, which does not cause deterioration of resolution due to its fluidity with time and is reversible by a single light source. It is an object of the present invention to provide an optical element capable of physically storing and erasing information.

[0004]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies on an optical element utilizing the change in the orientation of liquid crystal by light, and as a result, β-keto acid which causes a reversible structural change by light and heat. When the polymer thin film is formed in contact with the liquid crystal layer, the liquid crystal layer in contact with the thin film is reversibly aligned in parallel (parallel or homogeneous) or vertically (in accordance with the reversible structural change of β-keto acid by light and heat). Homeotropic)
Alignment, the alignment of the liquid crystal layer is to be rapidly transmitted even if the molecular overlap is 10,000 times or more that of the above compound,
Therefore, it was found that the liquid crystal layer does not change and information is retained for a long period unless the light state changes, and the present invention has been completed based on this finding.

That is, the present invention has the general formula (1)

[Chemical 5] (In the formula, R is an alkyl group, an alkoxy group or an alkylamino group, and A is a polymethylene group or a part of the methylene group therein.

[Chemical 6] A polymethylene group having a group represented by the formula
A polymer film made of polyvinyl alcohol, polyvinyl acetate, polyvinyl ether or polysiloxane is provided in contact with the liquid crystal layer to form a pattern by the action of heat, and the formed pattern is reversibly erased by light. (EN) An optical element characterized by being formed, and an optical element characterized in that a pattern is formed by the action of heat, and the formed pattern is reversibly erased by light. R in the group represented by the general formula (1) is an alkyl group having 5 to 8 carbon atoms, an alkoxy group having 5 to 8 carbon atoms,
An alkylamino group having an alkyl group having 5 to 8 carbon atoms is particularly preferable. Further, examples of A include a polymethylene group having 2 to 11 carbon atoms (where n is 2 to 11) and the like.

In the present invention, the polymer compound for forming the polymer film is preliminarily acrylate, methacrylate, vinyl acetate, vinyl ether or silanol.
After introducing the group of the general formula (1) into a monomer such as
It may be produced by polymerizing this, or
The polymer obtained by polymerizing the above-mentioned monomers has the general formula (1)
It may be produced by introducing the above group. All of these methods are well known as methods for producing a photofunctional polymer. (See Masahiro Irie, published by CMC in 1984, "Synthesis and Application of Photofunctional Polymer") Polymer compound obtained by polymerizing a monomer having a group represented by the general formula (1) introduced thereinto in advance. Explaining a specific example of the method for producing the compound, first, a substituted aniline derivative is diazotized by a conventional method, and the diazotized product is subjected to 0 to 10 ° C. in water or alcohol.
At a temperature of, in the presence of sodium acetate, sodium bicarbonate, sodium carbonate, etc., coupled to benzoyl acetic acid ethyl ester, the resulting azo compound is extracted by extraction, etc., and hydrolyzed at reflux temperature in the presence of potassium hydroxide in alcohol. By decomposing, the general formula (2)

[Chemical 7] A potassium salt of α-arylhydrazono-β-keto acid represented by the formula (wherein R has the same meaning as described above) is prepared. Next, by reacting this compound with a compound represented by the general formula X (CH2) OH or X (CH2) 2COOH (where X is a halogen atom) in the presence of an alkali catalyst in a solvent such as dimethylformamide, if necessary. , General formula (3)

[Chemical 8] (Z in the formula is-(CH2) xOH or-(CH2) xCOO
H, R and x have the same meanings as above). Next, the compound of the general formula (3) is mixed with acrylic acid or methacrylic acid chloride in a solvent such as ether,
In some cases, the reaction is carried out in the presence of an alkali at the reflux temperature, and the product is taken out by extraction, filtration or the like. This is radically polymerized using an initiator or the like according to a conventional method to obtain an acrylate-type or methacrylate-type polymer compound. Further, in order to introduce the group of the general formula (1) into the preformed polymer, for example, the compound of the general formula (3) is combined with polyvinyl alcohol or polyvinyl acetal in a solvent such as pyridine. The reaction is carried out to obtain a polymer compound having a β-keto acid derivative introduced into its side chain. Furthermore, when introducing into a polysiloxane, the aminoalkylated polysiloxane or aminoalkyltriethoxysilane and the carboxylic acid compound of the general formula (3) are condensed with dicyclohexylcarbodiimide in a solvent such as methylene chloride or chloroform, or It is obtained by polymerizing.

In this way, the general formula

[Chemical 9]

[Chemical 10]

[Chemical 11]

[Chemical 12]

[Chemical 13] A polymer compound having a structural unit represented by the formula (Y in the formula is a group represented by formula (1)) is formed.

The polymer compound thus obtained is dissolved in an easily volatile organic solvent such as dichloromethane, chloroform, methanol, ethanol or benzene, and the solution is cast or spin-coated on the substrate to form a polymer. A thin film is formed to obtain a light control alignment film. Further, a liquid crystal was introduced into the polymer coated substrate thus obtained to obtain an optical element. As the transparent substrate in the present invention, a sheet of ordinary silica glass, hard glass, quartz, various plastics, or the surface thereof, such as silicon oxide, tin oxide, indium oxide, aluminum oxide, titanium oxide, chromium oxide, zinc oxide, etc. A material having a coating such as a metal oxide or silicon nitride silicon carbide is used. Further, these may be treated in advance by a known method using a surface treatment agent such as an amphipathic compound or a silylating agent. Usually, the liquid crystal is used as a sandwich structure filled between two substrates, but in the present invention, at least one of the two substrates may be a transparent substrate and the other may be copper.
It is also possible to use a sheet of metal such as iron, aluminum or platinum, or a sheet coated with these metals. These substrates are usually used as a sheet having a smooth surface with a thickness of 0.01 to 1 mm. Next, as the liquid crystal of the liquid crystal layer provided on the β-keto acid polymer thin film that undergoes a reversible structural change by light and heat, from among conventionally known nematic, smectic and cholesteric liquid crystal substances, Any material can be selected, but in the case of a smectic liquid crystal substance, it is necessary to select a material that forms a nematic liquid crystal layer at a certain temperature. Further, it goes without saying that the liquid crystal substance includes not only low molecular weight substances but also high molecular weight substances. Such a liquid crystal material is, for example, A. Bekin (A.
Bequin) et al., "Molecular Crystals.
And Liquid Crystals (Molecular)
crystals and liquid Crys
tals) ", vol. 115, page 1. Polymeric liquid crystal materials are known, for example, in Advances in Polymer Science (Advances in
Polymer Science), Volume 60/61 (1984). These liquid crystal substances are
They may be used alone or in combination of two or more.

The present invention will now be described in more detail with reference to the accompanying drawings. FIG. 1 is a cross-sectional view showing the basic structure of the present invention. A thin film 2 of a polymer compound having an α-allylhydrazono-β-keto acid residue that undergoes a reversible structural change by light and heat is formed on a transparent substrate 1. It is provided and the liquid crystal layer 3 is further laminated thereon. Then, in order to prevent dissipation and damage, a substrate is further coated on this. This substrate may be transparent or opaque, and it is possible to use a substrate coated with a β-keto acid polymer compound that causes a reversible structural change due to light and heat, or to use a liquid crystal on the surface. It is also possible to use a film coated with a homogeneous alignment layer having an action of arranging in parallel with. FIG. 2 is a cross-sectional view showing an example of a preferred embodiment of the present invention, in which a polymer thin film 2 having α-allylhydrazono-β-keto acid residues is provided on the surface 2
It has a sandwich structure in which a liquid crystal layer is sandwiched between a plurality of substrates 1. In the figure, (a) shows a state before light irradiation, and (b) shows a state after light irradiation. Before light irradiation (ii), the liquid crystal is regularly arranged in the direction (homeotropic) perpendicular to the substrate surface by the action of the β-keto acid polymer thin film. Next, when a part (A) of this optical recording element is irradiated with light (b), the α-allylhydrazono-β-keto acid residue undergoes a structural change due to photoisomerization, so that the above-mentioned vertical alignment in that part occurs. When destroyed, the liquid crystal will be aligned parallel to the surface (parallel or homogeneous). Therefore, when this liquid crystal cell is placed between two orthogonal polarizers, the light-irradiated portion (A) is bright and the non-light-irradiated portion (B) is dark. Can read.
At this time, since light having a wavelength that does not cause photochromism of the α-allylhydrazono-β-keto acid residue can be used,
It can be read without destroying information. Next, FIG. 3 is an example of an embodiment different from the case of FIG. 2, and is an example in which the homogeneous alignment layer 4 is provided on one of the two substrates. This homogeneous alignment layer can be provided by rubbing the surface of the substrate with polyvinyl alcohol, a polyimide resin, polyoxyethylene or the like, or by vapor-depositing an oxide such as SiO2 from an oblique direction. As shown in FIG. 3A, the liquid crystal is aligned in the direction perpendicular to the substrate surface on the side of the polymer thin film having the α-allylhydrazono-β-keto acid residue, but on the side of the homogeneous alignment layer, the liquid crystal is aligned with the substrate. It has a structure arranged in parallel directions. When this is irradiated with light (b), in the irradiated part (A), the liquid crystal is aligned parallel to the β-keto acid polymer layer surface, so that the whole is in a homogeneous alignment state and is polarized by light in the same manner as described above. Information can be read. When the optical element of the present invention is used for optical recording and the recorded information is desired to be erased, the entire optical element of the present invention is heated to restore the structure of the β-keto acid polymer compound to its original state. You can The above is a method in which the liquid crystal alignment is changed wholly or partly by the action of light and is returned to the original liquid crystal alignment by the action of heat. On the contrary, the liquid crystal alignment is changed by the action of heat and the action of light is changed. It is also possible to return to the original liquid crystal alignment by. In this case, the entire optical element of the present invention is previously irradiated with ultraviolet rays to photoisomerize the α-allylhydrazono-β-keto acid residue, and the entire surface of the optical element is the same as the light irradiation portion (A) in FIG. 2 or FIG. Use parallel or homogeneous sequences. Then, heat is applied in a pattern-like manner, and only the heated portion is returned to the original structure of the α-allylhydrazono-β-keto acid residue, whereby the liquid crystal becomes a homeotropic alignment. Information can be erased by irradiating the entire surface of the optical element again with light. A thermal head can be used as a heat source for writing information. Furthermore, the optical element may be scanned by a known method with a laser beam that narrows the light of a semiconductor laser or a helium-neon laser that does not cause photoisomerization of the α-allylhydrazono-β-keto acid residue. Alternatively, the optical element may be irradiated through the mask with a xenon lamp or a xenon flash lamp that cuts the wavelength in the ultraviolet region that causes photoisomerization of the α-allylhydrazono-β-keto acid residue. When a heat source such as a laser or a xenon lamp is used, a dye that absorbs light of these wavelengths may be dissolved in the liquid crystal layer in advance. If a dichroic dye is used, it is also possible to write information by the shade of the dye without using a polarizing plate. Examples of the dichroic dye include Naotake Matsumura, “Dyeing Industry”, No. 32
Volume, page 215 (1984) is used. In this case, a liquid crystal substance having temperature dependence, for example, at room temperature, does not undergo structural change even when irradiated with light, but if a liquid crystal substance that undergoes structural change upon irradiation with light is heated to a certain temperature or more, dichroism can be obtained. A permanent record can be obtained based on the shade of the dye.

[0010]

EXAMPLES The present invention will be described in more detail with reference to examples. In the examples, "part" means "part by weight". Example 1 1.77 parts of para-n-hexylaniline and 5.0 parts of concentrated hydrochloric acid were placed in 30 parts of ice water and suspended with stirring. 0 to 5 ℃
A solution of 0.75 parts of sodium nitrite dissolved in 10 parts of water was appropriately added to the above suspension, and then diazotized at a temperature of 0 to 5 ° C for 1 hour. This diazo compound was treated with 1.95 parts of benzoyl acetic acid ethyl ester and 20 parts of ethanol,
The solution was added to a solution dissolved in 20 parts of ice water, and the pH was maintained at 6 to 8 with soda acetate and soda ash while maintaining the temperature at 0 to 5 ° C. to carry out a coupling reaction. The oily substance produced was extracted with dichloromethane and the solvent was distilled off. The obtained oily substance was dissolved in 30 parts of ethanol, 1.0 part of potassium hydroxide was added, and the mixture was hydrolyzed at reflux temperature for 1 hour. After that, the mixture was allowed to cool and solid matter was deposited. The precipitated solid matter is separated by filtration and dried to obtain the formula (4)

[Chemical 14] As a result, 2.5 parts of potassium salt of α-arylhydrazono-β-keto acid shown in 1) was obtained. Next, 3.89 parts of the compound of the formula (4) and 1.9 parts of 6-bromo-1-hexanol were added to 15 parts of dimethylformamide, and the mixture was reacted at a temperature of 20 to 60 ° C. for 12 hours. Then, 30 parts of water and 20 parts of dichloromethane were added and the mixture was extracted with dichloromethane, and the solvent was distilled off. The obtained oily substance was dissolved in 15 parts of diethyl ether, 1.0 part of acrylic acid chloride and 1.0 part of triethylamine were added, and the mixture was reacted at 10 to 50 ° C. for 4 hours. After the reaction, diethyl ether was distilled off, 30 parts of water and 20 parts of dichloromethane were added to extract the product. The solvent was distilled off, and the formula (5)

[Chemical 15] 3.2 parts of a compound of Next, 2.0 parts of the compound of the formula (5) was added to 10 parts of benzene, and radical polymerization was performed under deoxygenation conditions using 2,2′-azobis (isobutyronitrile) as an initiator to obtain α-aryl. Formula (6) having a hydrazono-β-keto acid unit

[Chemical 16] 2.0 parts of a polymer compound of 0.1 part of the polymer compound of the formula (6) was dissolved in 10 parts of chloroform, and this solution was spin-coated on a glass substrate under the condition of 2000 rpm and air-dried to obtain a polymer-coated glass. A substrate was obtained. A cyclohexylcarboxylic acid phenyl ester nematic liquid crystal (DON103, manufactured by Roddick) was sandwiched between the two substrates thus obtained through a glass rod spacer of 8 μm to form a liquid crystal cell. The liquid crystal orientation in the cell thus obtained was vertical and when placed between crossed nicols no light was transmitted and gave a dark screen. When this cell was irradiated with 365 nm ultraviolet light obtained by filtering a mercury lamp through a mask, photoisomerization of α-arylhydrazono-β-keto acid units was induced, and along with this, liquid crystal Changed from vertical alignment to horizontal alignment, and when the liquid crystal cell was placed between crossed Nicols, it transmitted light to give a bright image.
Subsequently, when this cell was irradiated with visible light of 440 nm or more obtained similarly by filtering a mercury lamp, the α-arylhydrazono-β-keto acid unit returned to its original structure by photoisomerization. Along with this, the liquid crystal changed its orientation again to vertical alignment, and did not transmit light in crossed Nicols, and returned to a dark screen. When hot air was blown to the liquid crystal cell instead of irradiating visible light, it returned to a dark screen. The reversible change in liquid crystal alignment due to the alternating operation of ultraviolet light / visible light or ultraviolet light / heating could be repeated many times. Example 2 Ethylene bromhydrin was used in place of 6-bromo-1-hexanol in Example 1 and the same procedure as in Example 1 was carried out to obtain formula (7).

[Chemical 17] Was obtained. The obtained polymer compound of formula (7) was applied onto a glass substrate in the same manner as in Example 1 to form a liquid crystal cell. The liquid crystal cell thus obtained showed a reversible liquid crystal orientation change due to alternating irradiation of ultraviolet light / visible light or ultraviolet light / heat treatment as in Example 1. Example 3 11-Bromo-1-undecanol was used in place of 6-bromo-1-hexanol in Example 1, and the formula (8) was obtained by the same operation as in Example 1.

[Chemical 18] Was obtained. The obtained polymer compound of formula (8) was applied onto a glass substrate in the same manner as in Example 1 to form a liquid crystal cell. The liquid crystal cell thus obtained exhibited reversible liquid crystal orientation change due to alternating irradiation of ultraviolet light / visible light or ultraviolet light / heat treatment as in Example 1. Example 4 Para-n-heptanoxyaniline was used in place of para-n-hexylaniline, which is the diazo component in Example 1, and the formula (9) was obtained by the same operation as in Example 1.

[Chemical 19] Was synthesized. The obtained compound of formula 9) was applied on a glass substrate in the same manner as in Example 1 to form a liquid crystal cell. The liquid crystal cell thus obtained exhibited reversible liquid crystal orientation change due to alternating irradiation of ultraviolet light / visible light or ultraviolet light / heat treatment as in Example 1. Example 5 Para-n-pentylaminoaniline was used in place of para-n-hexylaniline, which is the diazo component in Example 1, and the formula (10) was used by the same operation as in Example 1.

[Chemical 20] Was synthesized. The obtained compound of formula (10) was applied onto a glass substrate in the same manner as in Example 1 to form a liquid crystal cell. The liquid crystal cell thus obtained exhibited reversible liquid crystal orientation change due to alternating irradiation of ultraviolet light / visible light or ultraviolet light / heat treatment as in Example 1. Example 6 Using the methacrylic acid chloride instead of the acrylic acid chloride in Example 1, the same procedure as in Example 1 was carried out to obtain the compound of formula (11).

[Chemical 21] Was synthesized. The obtained compound of formula (11) was applied onto a glass substrate in the same manner as in Example 1 to form a liquid crystal cell. The liquid crystal cell thus obtained exhibited reversible liquid crystal orientation change due to alternating irradiation of ultraviolet light / visible light or ultraviolet light / heat treatment as in Example 1. Example 7 2.5 parts of the compound of formula (5) obtained in Example 1 was dissolved in 15 parts of toluene, 1.6 parts of aminopropyltriethoxysilane was added, and the mixture was reacted at reflux temperature for 16 hours. Then, toluene was distilled off, 15 parts of water-containing ethanol was added, and the reaction was continued at the reflux temperature for 6 hours. After the reaction, the solvent is distilled off to obtain the compound of formula (12)

[Chemical formula 22] To obtain 3,8 parts of the compound of. Polymer compound of formula (12)
05 parts was dissolved in 10 parts chloroform, and this solution was applied by casting to a glass substrate and dried to obtain a polymer-coated glass substrate. A liquid crystal cell was obtained by sandwiching a cyclohexyl carboxylic acid phenyl ester nematic liquid crystal (DON103, manufactured by Roddick) between the two substrates thus obtained through an 8 μm glass rod spacer. The liquid crystal cell thus obtained exhibited reversible liquid crystal orientation change due to alternating irradiation of ultraviolet light / visible light or ultraviolet light / heat treatment as in Example 1. Example 8 In place of 6-bromo-1-hexanol in Example 1, ethylene bromhydrin was used to obtain the compound of formula (13).

[Chemical formula 23] Was synthesized. Using this, by the same operation as in Example 7, the formula (14)

[Chemical formula 24] Was obtained. The obtained polymer compound of formula (14) was applied onto a glass substrate in the same manner as in Example 7 to form a liquid crystal cell. The liquid crystal cell thus obtained exhibited reversible liquid crystal orientation change due to alternating irradiation of ultraviolet light / visible light or ultraviolet light / heat treatment as in Example 1. Example 9 11-Bromo-1-undecanol was used in place of 6-bromo-1-hexanol in Example 1, and the compound of the formula (15) was used.

[Chemical 25] Was synthesized. Using this, by the same operation as in Example 7, the formula (16)

[Chemical formula 26] Was obtained. The obtained polymer compound of formula (16) was applied onto a glass substrate in the same manner as in Example 7 to form a liquid crystal cell. The liquid crystal cell thus obtained exhibited reversible liquid crystal orientation change due to alternating irradiation of ultraviolet light / visible light or ultraviolet light / heat treatment as in Example 1. Example 10 Using aminopentyltriethoxysilane in place of aminopropyltriethoxysilane in Example 7,
By the same operation as in Example 7, formula (17)

[Chemical 27] Was synthesized. The obtained compound of formula (17) was applied onto a glass substrate in the same manner as in Example 7 to form a liquid crystal cell. The liquid crystal cell thus obtained exhibited reversible liquid crystal orientation change due to alternating irradiation of ultraviolet light / visible light or ultraviolet light / heat treatment as in Example 1. Example 11 1.95 parts of the compound of formula (4) obtained in Example 1 are dissolved in 15 parts of dimethylformamide and bromoacetic acid-t-
1.1 parts of butyl ester was added, and the mixture was reacted at 20 to 40 ° C for 2 hours. Then, 20 parts of water and 20 parts of benzene were added, the reaction product was extracted with benzene in an acidic state, and the solvent was distilled off to obtain the compound of the formula (18).

[Chemical 28] 2.1 parts of a compound of Then, the compound of the formula (18) 2.0
Parts were dissolved in 20 parts of dichloromethane, 1.6 parts of aminopropyltriethoxysilane and 1.1 parts of dicyclohexylcarbodiimide were added, and the mixture was reacted at 20 to 40 ° C. for 6 hours. Then, the insoluble matter is filtered off, the solvent is distilled off, and
9)

[Chemical 29] 3.2 parts of a compound of Polymer compound of formula (19)
05 parts was dissolved in 10 parts of methanol, and this solution was applied by casting to a glass substrate and dried to obtain a polymer-coated glass substrate. Using this substrate, a liquid crystal cell was formed in the same manner as in Example 7. The liquid crystal cell thus obtained exhibited a reversible change in liquid crystal alignment due to ultraviolet light / heat.
That is, in this liquid crystal cell, horizontal alignment of the liquid crystal was obtained by irradiation with 365 nm of ultraviolet light, but 440 nm.
The orientation did not change in the vertical direction when exposed to visible light. The change to the vertical alignment was performed by heating at 60 to 70 ° C. Example 12 Using 6-bromo-n-caproic acid instead of bromoacetic acid-t-butyl ester in Example 11, the same procedure as in Example 11 was carried out to obtain the compound of formula (20).

[Chemical 30] Was obtained. The obtained compound of formula (20) was applied onto a glass substrate in the same manner as in Example 11 to form a liquid crystal cell. The liquid crystal cell thus obtained showed reversible liquid crystal alignment change due to ultraviolet light / heat similar to that of Example 11. Example 13 Using 8-bromo-n-nonanoic acid in place of bromoacetic acid-t-butyl ester in Example 11, the same procedure as in Example 11 was carried out to obtain formula (21).

[Chemical 31] Was obtained. The obtained compound of formula (21) was applied onto a glass substrate in the same manner as in Example 11 to form a liquid crystal cell. The liquid crystal cell thus obtained showed reversible liquid crystal alignment change due to ultraviolet light / heat similar to that of Example 11. Example 14 Using 6-bromo-n-caproic acid instead of bromoacetic acid-t-butyl ester in Example 11, the same procedure as in Example 11 was carried out to obtain the compound of formula (22).

[Chemical 32] Was obtained. Next, 2.3 parts of the compound of formula (22) was dissolved in 15 parts of benzene, 1.5 parts of thionyl chloride was added, and the mixture was reacted at reflux temperature for 4 hours. Then, excess thionyl chloride and the solvent were distilled off, and polyvinyl alcohol
A solution of 0.4 parts of pyridine in 10 parts of pyridine was gradually added, and the mixture was reacted at reflux temperature for 6 hours. After the reaction, the solvent is distilled off to give the compound of formula (23)

[Chemical 33] 1.8 parts of a compound of Polymer compound of formula (23)
Dissolve 1 part in 10 parts of chloroform and add 25 parts of this solution.
Spin coat on a glass substrate under the condition of 00 revolutions / minute,
A glass substrate coated with a polymer was obtained by air-drying. A cyclohexylcarboxylic acid phenyl ester nematic liquid crystal (DON103, manufactured by Roddick) was sandwiched between the two substrates thus obtained through a glass rod spacer of 8 μm to form a liquid crystal cell. The liquid crystal cell thus obtained was prepared as in Example 1.
The same reversible change in liquid crystal orientation was observed as a result of alternating irradiation of ultraviolet light / visible light or ultraviolet light / heat treatment. Example 15 Para-n-octylaniline was used in place of para-n-hexylaniline, which is the diazo component in Example 1, and the same operation as in Example 1 was carried out, followed by Example 14.
Perform the same operation as in formula (24).

[Chemical 34] Was obtained. Next, 2.5 parts of the compound of formula (24) was dissolved in 15 parts of benzene, 2.0 parts of thionyl chloride was added, and the mixture was reacted at reflux temperature for 5 hours. Then, excess thionyl chloride and the solvent were distilled off, and a solution prepared by dissolving 0.3 parts of polyvinyl acetate in 10 parts of pyridine was gradually added, and the mixture was reacted at a reflux temperature for 6 hours. After the reaction, the solvent is distilled off to obtain the compound of formula (25)

[Chemical 35] 1.6 parts of a compound of The liquid crystal cell thus obtained exhibited reversible liquid crystal orientation change due to alternating irradiation of ultraviolet light / visible light or ultraviolet light / heat treatment as in Example 1.

[0011]

INDUSTRIAL APPLICABILITY The optical element using the light control alignment film of the present invention does not have a drawback of information recording by the conventional photochromic material, for example, information once recorded gradually disappears by repeated reading. In addition, since the alignment of the liquid crystal is controlled by the photochromic polymer thin film of β-keto acid, even if a low-molecular liquid crystal having fluidity is used, the solution is better than the case where a conventional photochromic compound is added to the liquid crystal. The image quality is far superior. or,
The optical recording element of the present invention can be suitably used not only for reversible optical information storage but also for optical address type display. Further, the β-keto acid polymer used in the present invention has good adhesion to the substrate, is a simple and suitable light control alignment film for manufacturing a liquid crystal cell, and has high industrial value.

[0012]

[Brief description of drawings]

FIG. 1 is a sectional view showing a base structure of the present invention.

FIG. 2 is a cross-sectional view showing a liquid crystal array before and after light irradiation according to an example of the present invention.

FIG. 3 is a cross section showing a liquid crystal alignment before and after light irradiation according to another example of the present invention.

[Explanation of symbols]

1. ． Substrate, 2. ． Polymer membrane layer, 3. ． Liquid crystal layer, 4. ．
Homogenous alignment layer

Continuation of the front page (51) Int.Cl. ⁵ Identification number Reference number within the agency FI Technical display location G02F 1/1337 520 9225-2K G11B 7/24 A 7215-5D (56) References Japanese Patent Publication 4-40395 ( JP, B2) JP-B-63-38044 (JP, B2)

Claims (2)

[Claims] 1. A general formula (1): (In the formula, R is an alkyl group, an alkoxy group or an alkylamino group, and A is a polymethylene group or a part of the methylene group therein. A polymer film having a group represented by the formula (i.e., a polymethylene group which is replaced by) in the side chain, and made of polyacrylate, polymethacrylate, polyvinyl acetal, polyvinyl ether or polysiloxane. An optical element, which is characterized in that a pattern is formed by the action of light, and the formed pattern is reversibly erased by heating. 2. General formula (1): (In the formula, R represents an alkyl group, an alkoxy group or an alkylamino group, and A represents a polymethylene group or a part of the methylene group therein. A polymer film having a group represented by the formula (i.e., a polymethylene group which is replaced by) in the side chain, and made of polyacrylate, polymethacrylate, polyvinyl acetal, polyvinyl ether or polysiloxane. An optical element, which is characterized in that a pattern is formed by the action of heat and the formed pattern is reversibly erased by light.