JPS60104180A - Liquid crystal element - Google Patents

Abstract

PURPOSE:To provide the titled element capable of forming optical image corresponding to the optical signal transmitted from He-Ne laser, YAG laser, semiconductor laser and Ar laser, comprising a liquid crystal composition containing specific azulenium compound. CONSTITUTION:The objective element comprising a liquid crystal composition containing pref. 1-5wt% of an azulenium compound of formula [R1, R1', R2, R3, R3', R4, R4', R5, R5', R6, R6', R7 and R7' are each H, halogen or monovalent organic residue (e.g. alkyl, alkoxy, aryl, aralkyl, acyl, amino, etc.), Z<-> is anonic residue]. Said compound will be prepared by the reaction, in a solvent such as alcohol or nitrile in the presence of strong acid at room temperature- boiling point, between 1,3-diformyl azulene compound and the orginal azulene compound.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a PTK element that can be used in a thermal writing method, and more particularly, the present invention relates to a PTK element that can be used in a thermal writing method, and more particularly, to a PTK element that can be used in a thermal writing method, and more specifically, to write an optical signal generated from a laser beam, specifically a helium-neon laser, a YAG laser diode laser, or an argon laser. The present invention relates to a liquid crystal element that can form an optical image corresponding to the above.

Until now, we have prepared liquid crystal devices in which a mixed liquid crystal of nematic liquid crystal with negative dielectric anisotropy and cholesteric liquid crystal or smectic liquid crystal with positive dielectric anisotropy is arranged between two glass substrates. When an lfM crystal element r- is irradiated with a laser beam, that part is heated locally rjR to an intropic phase, and then by careful cooling, the liquid crystal becomes a liquid crystal with a random orientation different from the initial uniform orientation state. A phase is formed. As a result, light scattering occurs at the location where the laser beam is irradiated, resulting in a difference in optical characteristics between the liquid crystal phase in the background region, which is in a uniformly aligned state.

This type of liquid crystal element is also capable of erasing an optical image formed by laser reading using the method described above. That is, by providing electrodes on each of the two substrates that make up the liquid crystal element, and heating the entire liquid crystal element with a heat source other than the laser beam (for example, a heater), the liquid crystal phase is changed to the isopropink phase. The above procedure is carried out by heating, and then cooling with a voltage applied between the electrodes until, for example, a homeotopic structure in the case of a smectic liquid crystal, a lopic structure, or a Grandshuan structure in the case of a cholesteric-nematic liquid crystal are formed. The optical image formed by writing can be erased.

This liquid crystal element has the advantage that it can form an image pattern simply by scanning optical signals converted from electrical signals, which requires a matrix electrode structure to form pixels, and that it can be obtained on a large screen. have.

On the other hand, as a means of converting electrical signals from computer terminals into optical signals, a laser beam has been modulated by a drive signal according to digital image information, and this modulated laser beam is sent to an imaging lens, galvanometer mirror, etc. A scanning method is adopted through an optical system consisting of a light deflector. In particular, in recent years, semiconductor lasers have come to be used as beam sources for such optical signal generators.

The semiconductor laser described above generally has a long wavelength range (for example, 750 nm).
Despite having an oscillation wavelength of 1 mm or more, the above-mentioned liquid crystal elements have low heat conversion efficiency for long wavelength beams, so when writing to liquid crystal elements using a semiconductor laser, a high-power laser is required. It became necessary to irradiate it with a beam. However, the power of a semiconductor laser is lower than that of a laser such as an alcone laser or a helium-neon laser, and therefore the optical signal from an optical signal generator using a semiconductor laser is scanned into the liquid crystal element f- as described above. However, there is a drawback that sufficient writing cannot be performed even if the optical signal is controlled, or writing can only be performed by slowing down the scanning speed of the optical signal sufficiently.

For this purpose, conventionally, for example, "5ociety of I
nformation Display Intern
ational Symposium.

Digest of Technicai Paper
"P, P34-48, 172-187.

238-253 (1882), a guest-post type laser thermal writing type liquid crystal element in which a black dye is mixed into a smectic liquid crystal has been proposed.

However, even this type of liquid crystal element does not have sufficient efficiency in absorbing the laser beam of a semiconductor laser and converting it into thermal energy, and requires high power or low speed optical signal scanning. This point is similar to the drawback of the liquid crystal element f of the system disclosed in British Publication No. 2091753. However, the liquid crystal element using the above-mentioned black dye has a drawback in that a white image pattern is formed on a black background, which does not provide a good display for humans.

Therefore, an object of the present invention is to eliminate the above-mentioned drawbacks and provide a liquid crystal element capable of forming an optical image pattern in response to scanning of an optical signal from an optical signal generator using a laser oscillator. It's about doing.

The present invention is characterized in that it uses a liquid crystal composition in which a compound represented by the following general formula (1) is dissolved in liquid crystal.

General formula (1) where R,,RS ,R,,R34t(,n, ,n2
, all, R'l+RHRLR1 and Rj each represent a hydrogen atom, ) and a rogene atom (chlorine atom, bromine atom, iodine atom) each representing a monovalent organic residue. Monovalent organic residues can be selected from a wide variety of groups, but in particular alkyl groups (methyl, ethyl, n-propyl, isopropyl, n-butyl, t-butyl, n-amyl, n-hexyl, n-octyl, 2-ethylhexyl, t-octyl, etc.), alkoxy groups (methoxy, ethoxy, propoxy, butoxy, etc.), substituted or aryl groups (phenyl, tolyl, xylyl, ethylphenyl, methoxyphenyl, ethoxy) phenyl, chlorophenyl, nitrophenyl, dimethylaminophenyl, α-naphthyl, β-naphthyl, etc.), substituted or unsubstituted aralkyl groups (benzyl, 2-phenylethyl, 2-phenyl-1-methylethyl, bromobenzyl, 2 -7” romophenylethyl, methylbenzyl, methoxybenzyl, nitrobenzyl), 1 syl group (acetyl, flobionyl,
(bunaryl, valeryl, benzoyl, trioyl, naphthoyl, phthaloyl, furoyl, etc.), yellow-choo or non-isolated γ-bano group (amino, dimethylaξ), di-1-lylamino, difuropylamino, acetylamino, pen/diylamine, etc.) , place ↓ or not q +99 styryl (styryl, dimethylaminostyryl, diethylaminostyryl, diethylaminostyryl, methoxystyryl, ethoxystyryl, methylstyryl), nitro group, hydroxy group, carboxyl group, cyano group or (
can be a substituted or unsubstituted If-substituted arylazo group (phenylazo, α-naphthylazo, β-naphthylazo, dimethylaminophenylazo, chlorophenylazo, nitrophenylazo, methoxyphenylazo, tolylazo, etc.). Father, R1 and R2, R3 and R,, R4
and R1, R.

and R6, at least one of the combinations of Ro and R7
A combination of substituted or unsubstituted aromatic rings (benzene, naphthalene, chlorobenzene, bromobenzene, methylbenzene, ethylbenzene, methoxybenzene, ethoxybenzene, etc.) may be of the form +ji L.

At least one combination of substituted or unkeyed aromatic rings (benzene, naphthalene, , chlorobenzene, bromobenzene, methylbenzene, ethylbenzene, methoxybenzene, ethoxybenzene, etc.).

In addition, 2θ in the formula represents verchlorate, fluoroborate, sulfoacetate, iodide, chloride, bromide, P-toluenesulfonate, alkylsulfonate, algyldisulfonate, benzenedisulfonate, 10sulfonate, picrate, tetracyanoethylene Represents anion residues such as r anion and tetracyanoquinodimethane anion.

Specific examples of the γZ1/Ni penta-salt compounds used in the present invention are listed below.

As shown in ReQ, the 1,3-dipromylazulene compound and the amelene compound are heated in a suitable solvent in the presence of a strong presence.

The reaction solvents used include alcohols such as ethanol, butanol, and benzyl alcohol, nitriles such as acetonitrile and fropionitrile, organic carboxylic acids such as acetic acid, acid hydrides such as acetic anhydride, dioxane, tetrahydrofuran, etc. Tetracyclic ethers, etc. are used. Furthermore, aromatic hydrocarbons such as benzene can be mixed with butanol, benzyl alcohol, and the like. The temperature during the reaction can be selected from the range of room temperature to boiling point.

Sweat Formation Example t (Compound A2) 1.4 g of 1,5-dimethylazulene and 1,4-dimethyl-7-inflovir in 70rnfJ of glacial acetic acid.
6.09% of Dulen was added and heated and stirred to make it 1050%.

Add 5.4 tnQ of 70% perchloric acid to this solution and add at the same temperature [
After heating for 5 minutes, the precipitate was washed with glacial acetic acid, washed twice with 50% water, and dried to obtain 2.4 g of masticatory dye. Ta.

(Yield 65) 2.0 g of the product was recrystallized from acetonitrile to obtain 1.2 g of compound/f62.

Melting point: 2600 or more (capillary method) Solution i second yield spectrum: λ in glacial acetic acid. ax=660nm Elemental analysis: Molecular formula C<t H4t C401 Calculated value (%) Analysis value (%) C! 67.64 67.76 H5,695,78 C(1,9,519,!+ 1 Next, the liquid crystal element of the present invention will be explained according to the drawings.

FIG. 1 shows a cross-sectional view of a liquid crystal element of the present invention.

As the M product composition +08, a liquid crystal in which the compound represented by the above-mentioned general formula (1) is dissolved is used. The liquid crystal used in the device of the present invention is Smect.

Suitable liquid crystals are A-phase or C-phase of smectinic liquid crystals having positive dielectric anisotropy.

Such smectinic liquid crystals are arranged in a smectic phase of a homeotrophic pink structure until they are locally heated by a laser beam, and the smectic phase of a homeotropic pink structure that is not equal to y1 in terms of temperature → nematic phase → Can change phase to isodoropink phase. Next, when the phase is changed from the intropic phase to the smectic phase in a rapidly cooled state, a smectic phase with a focal conic structure having light scattering properties is formed. Therefore, when the smectic phase in the liquid crystal element r- is locally heated to an isotropic phase by irradiation with a laser beam, and then cooled by S, the smectic phase of the force-luconinck structure is formed at that location, and this state has light scattering properties. Therefore, a still image pattern can be formed by optical scanning using the laser beam described above.

The invention! Examples of compounds capable of forming a smectic phase with a constant dielectric anisotropy used in α-crystal elements include those disclosed in JP-A-56-150030, JP-A-57-40428, and JP-A-57-51779. Compounds described in, etc. can be used.

The compound represented by the above-mentioned general formula (1) is used in an amount of 0.1% by weight or more, preferably 1% to 3% by weight based on the liquid crystal.
It can be contained in the liquid crystal composition 108 within a range of t%.

Further, the liquid crystal element of the present invention can also use a mixed liquid crystal of smectic liquid crystal and cholesteric liquid crystal having positive dielectric anisotropy. Cholesterlink LCD! It is suitable to contain it in the α-crystal composition 108 in a range of 0.5% by weight to 15% by weight, preferably in a range of 1% by weight to 5% by weight.

Cholesteric crystallization that can be used in the present invention includes cholesteryl chloride, cholesteryl bromyl 1ζ, cholesteryl iodite, cholesteryl nitrate, cholesteryl chloroticani 1, cholesteryl butyrate,
Examples include cholesteryl compounds such as cholesteryl caprate, cholesteryl oleate, cholesteryl oleate, cholesteryl laurate, cholesteryl myristate, cholesteryl heptyl carbamate, cholesteryl decyl ether, cholesteryl lauryl ether, and cholesteryl oleyl ether.

A liquid crystal element using such a mixed liquid crystal undergoes a phase change from a homeotropic smectic phase to an isotropic phase by local heating with a laser beam, and when this is rapidly cooled, a focal conic Ml woven smectic phase is formed as described above. can do.

The liquid crystal element recorded by the above-mentioned method uses liquid crystal composition 1.
After heating the entire surface of 08 with a heater to change the phase to an intropic phase, electrodes 103 are provided on substrates 101 and 102 (for example, plastic plates such as transparent glass plates and acrylic plates) constituting the liquid crystal element. By applying a suitable direct current or alternating current between and 104 and slow cooling, a phase change can occur from an intro pink phase to a nematic phase to a smectic phase. At this time, since the liquid crystal has a positive dielectric anisotropy in the nematic phase, nematic static crystals are aligned in the direction of the electric field, and a smectic A phase or C phase with a homeotropic structure is formed for further cooling. The image pattern is erased. Electrode 103
and 104 are generally obtained by a transparent conductive film of indium oxide, tin oxide, or I To (Indium Tin 0w1de), and if necessary, a metal groove of aluminum, chromium, silver, nickel, etc. can get. These electrodes 81103 and 104 are desirably coated over the entire surface of the plates 101 and 102, and do not necessarily have to have a predetermined pattern shape or matrix electrode structure. It is also possible to design a pattern shape or matrix electrode structure.

The liquid crystal element of the present invention has alignment control films 106 and 10 made of an insulating material coating on the electrodes 103 and 104, respectively.
7 can be provided. This alignment control +1qloe and 107 innovate a surface structure that can control the alignment direction of the liquid crystal composition +08 that is in contact with these critical surfaces to a desired state. Also, this orientation side till II chestnut 10
G and 107 also function as an insulating film that can prevent the generation of a current flowing through the liquid crystal M1 composition 108. This kind of orientation control 1&! +06 and 107 are, for example, silicon oxide, -Hpg silicon oxide, aluminum oxide, zirconia, magnesium fluoride, cerium oxide, cerium fluoride, silicon nitride, silicon carbide, boron, (; nitride, polyvinyl alcohol, Polyino 1ζ,
Polyamide imide, polyparaxylerin, polyester, polycarbonate, polyvinyl acecool, polyIJ, vinyl hydride, polyamide, polystyrene, cellulose resin, melamine resin, urea resin, acrylic resin, orcasiloxane, polyfluorinated ethylene, etc. Steaming an insulating material]
It can be obtained by engraving IIQ using a method, a dip coating method, a spinner Qllj method or a spray coating method.

The alignment control films 10B and 107 are coated with the liquid crystal composition 108 by rubbing their surfaces with 7Ij, paper, velvet, or the like, or by using the pierced stone method during film formation, depending on the predetermined writing method. It is possible to have a surface structure with homocyanic orientation, or the surface can be formed by, for example, a perfluoroalkyldi compound described in JP-A No. 50-36150 +17, and a nran compound having a perfluoroalkyl di-(described in JP-A No. 50-50947). By treating with a compound such as a dirty alkyltrialkoxysilane, such as the tetraalkoxysilane described in JP-A-50-63955%, the liquid crystal composition 108 has a surface structure that allows the liquid crystal composition 108 to have a homeo-1-ropic orientation. I can do it.

The optimum film thickness of the orientation i1ff control 11jJ10G and 107 differs depending on the type of insulating material used, but generally 100A-1. range, preferably 500A
It is suitable for the thickness to be within the range of ~2000A, and it is desirable that the film thickness is set so that the alignment control films 106 and 107 also function as anti-reflection film 11Q.

In addition, the liquid crystal element of the present invention forms the above-mentioned still image by irradiating the laser beam HQ from the rear direction as shown in the figure, and from the front direction it receives 18! of natural light, halogen lamp light, xenon lamp light, fluorescent lamp light, etc. The light detector 108 is made to enter the element, and this light beam is reflected from the cold mirror 105, and the image is transferred to +1tl I mentioned above.
can be understood. This cold mirror 105 generally has a sufficiently high reflectance for visible light, and has a reflectance of 800
It has high transmittance characteristics for long wavelength light of mm or more. Specifically, Ge/MgF2 (1/4 person) /C
e02 (1/4λ) 7MgF2 (+/4 people)/Ce0
A multilayer film consisting of 2 (+/4) members is known.

However, in the present invention, the use of cold mirror 105 can also be omitted. Furthermore, in the element of the present invention, a cold filter (not shown) can be provided between 1ltJi 103 and the alignment control film IH. This cold filter has a sufficiently high transmittance of 41 for visible light and a sufficiently high reflectance for long wavelength light.

Next, FIG. 2 shows an example in which a display pattern was formed using the liquid crystal element of the present invention.

Among the compounds represented by general 2'(1) above, compound No. 2 was added in an amount of 2% by weight based on the highest smectic compound (4,4'-cyanooctylbinoenyl; having dielectric anisotropy of pressure). It was dissolved in a proportion of . At this time, the liquid crystal composition is heated until it becomes an intropic phase, the above-mentioned compound is added, the liquid is poured into a cell whose inner wall surface is subjected to homeotropic alignment heat, and then slowly cooled. A smectic phase liquid crystal with a Pome-first-ropic structure was formed.

Laser oscillation to emit a laser beam used to write an image on the liquid crystal cell 201! 4202 can be selected from those with wavelengths corresponding to the absorption efficiency of the above-mentioned compounds contained in the liquid crystal, but in particular long wavelength laser beams emitted from helium-neon lasers, semiconductor lasers, or YAG lasers, or A short wavelength laser beam emitted by an argon laser can be used.

The laser beam emitted from the laser oscillator 202 is transmitted through a modulator 203, a slit I/204, and a Y-axis deflector 205.
, X1llll deflector 206 to be modulated and deflected, a writing lens 208 converts the light into one beam, and the light is irradiated from the back side of the liquid crystal front j'-201 via a gicroic mirror 209. The aforementioned modulator 203, Y-axis deflector 205, and X-axis deflector 206 are connected to the drive 7-11
11. is connected to a signal source 211 via a signal source 210, which controls the laser beam 1 and converts the digital signal from the signal source 2+1 into an optical signal (:r"").
Convert to r. An image pattern is written in front of the liquid crystal r201 by this optical signal.

Thereafter, the Peltier collector 212 installed around the liquid crystal element 20+ is operated by the power source 213 to rapidly cool the full crystal conduit f-201.

forming a smectic phase with focal conic structure,
An image pattern was formed in which the portions irradiated with the optical signal were in a light scattering state. At this time, Benilche, +CR-21
2 is heated and rolled by a temperature controller 214.

This image pattern can be observed by turning on the illumination source 215 placed on the 611th surface of the r-201 in front of the liquid crystal.

Then, to erase the aforementioned image pattern,
Transparent heater 216 provided in f-2QI (for example.

An indium oxide film, a tin oxide film, an ITO II film) is heated by a heater power source 2]8 via a temperature controller 217 to cause a phase change from a liquid crystal phase to an isodoropink phase. After that, the 'city pole 219 provided on the liquid crystal element 201
While applying no voltage from the AC power source 221 between and 220, -J&Crystalline-201 was slowly cooled to form a smectic phase with a home-like structure and a pink structure.

As a result, the image pattern that was filled in was erased.

The liquid crystal front r- of the present invention can be used as a large screen display.
It is also possible to use light (iJ
It can also be applied to an optical disk system of a recording type in which pits are formed by scanning 'J along a tractor.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of 1, 4: f- in front of the liquid crystal of the invention. FIG. 2 is an explanatory diagram showing one example of a display method using the liquid crystal front f of the present invention. 101, 102. No person board 103, 104, electrode 105: cold mirror 106.107. Orientation side it'll II cost 108: liquid crystal composition IO2; observation light 110; laser beam

Claims (1)

[Scope of Claims] A liquid crystal element characterized by having a liquid crystal composition containing one crystal and a compound compound represented by the following general formula (1). General formula (1) ( (in the formula RI I R 'l r ”t + R1*
RQ ,R,,u′,,)E,,RQ,R,,Rchi,
R? R4 represents a hydrogen atom, a halogen atom, or a monovalent organic residue. ze represents an anionic residue)