JPS60104182A - 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-R7 are each H, halogen or monovalent organic residue (e.g. alkyl, alkoxy, aryl, aralkyl, acyl, amino); Z<-> is anionic residue (e.g. perchlorate, fluoroborate, sulfoacetate)]. 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 azulene compound and glyoxal.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a liquid crystal element that can be used in a thermal writing method.
Specifically, the invention relates to a liquid crystal element capable of forming an optical image corresponding to an optical signal generated from a laser beam, specifically a helium-neon laser, a YAG laser, a semiconductor laser, or an argon laser.

Until now, we have prepared liquid crystal devices in which a mixed liquid crystal of nematic liquid crystal and cholesteric liquid crystal with negative dielectric anisotropy or smectic liquid crystal with positive dielectric anisotropy is placed between two glass substrates. When the element is irradiated with a laser beam, the area is locally heated to an intropic phase, and then rapidly cooled to form a liquid crystal phase with a random alignment state different from the initial uniform alignment state. As a result, light scattering occurs at the location where the laser beam is irradiated, resulting in a difference in optical properties from 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 aging 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 can be changed. For example, in the case of smectic liquid crystals, a homeotropic liquid crystal is formed by heating to the intro pink phase and then applying a voltage between the electrodes.
/% Li In the case of a cholesteric-nematic liquid crystal, the optical image formed by previous writing can be erased by cooling it until a Grandshuan structure is formed.

This liquid crystal element does not require a matrix electrode structure to form pixels, and can form a no-turn image simply by scanning an optical signal converted from an electrical signal.The main advantage is that it can be obtained on a large screen. 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 focused into an image. A method of scanning is adopted through an optical system consisting of a light deflector such as a lens or a galvanometer mirror. 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 element has a low thermal conversion efficiency for long wavelength beams, so when writing to a liquid crystal element using a semiconductor laser, It became necessary to irradiate with a high-power laser beam. However, semiconductor lasers generally have lower power than gas lasers such as argon lasers and helium-neon lasers, so it is not sufficient to scan a liquid crystal element as described above with an optical signal from an optical signal generator using a semiconductor laser. There is a drawback that writing cannot be performed, or writing can only be performed by slowing down the scanning speed of the optical signal sufficiently.

For this purpose, conventionally, for example, 5ociety ofIn
display format
tional Symposium.

Digest of Technical Paper
"P, P34-49, 172-187゜238-253
(1882), a guest-host 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 a laser beam from 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 lid of the method disclosed in British Publication No. 2081753. Moreover, the above-mentioned liquid crystal element using a black dye has a drawback in that a white image pattern is formed on a black background, which does not provide a good display.

Therefore, the object of the present invention is to provide a liquid crystal element which eliminates the above-mentioned drawbacks and can form an optical image pattern in response to scanning of an optical signal from an optical signal generator using a laser oscillator. It is in.

The present invention is characterized in that it uses a liquid crystal composition in which a compound represented by the following general formula (]) is dissolved in a liquid crystal. 〜■Mo, is a hydrogen atom, a halogen atom (chlorine atom, bromine atom, iodine atom) k is a monovalent 4. The residue is ``(was. 41 monovalent residue) -
C can be selected from Hiro Ida, but 11
"To alkyl groups (methyl, coateur, 1]-propyl, isopropyl, I+-butyl, t-butyl, "l-
゛Amyl, 11-hexyl, n-octyl, 2-ethylhexyl, t-octylinato), alkoxy, u; lj
(methoxy, ethoxy, propoxy, butoxy, etc.)
, if: j-1fi or un-C-substituted aryl group (phenyl, tolyl, xylyl, ethylphenyl, methoxyphenyl, ethoxyphenyl, chlorophenyl, nitrophenyl, dimethylaminophenyl, α-naphthyl, β
- Naphternyodo LliM' is small or not yet accepted” (q
l aralkyl group (h/syl, 2-phenylethyl, 2
-phenyl-1-) f-ethyl, bromopenzyl, 2-
Bromophenylethyl, methylbenzyl, methane/
zyl, nitrobenzyl), acyl group (acetyl, gropionyl, butyryl, valeryl, pe/soyl, triooyl, naphthoyl, phthaloyl, 70yl, etc.), 1r-
CIq or t, < is an unsubstituted amino group (amine, dimethylamine, diethylamino, diethylamino, acetylamino, benzoylamino, etc.), a 14-substituted or unsubstituted styryl group (styryl, dimethylaminostyryl, diethylaminostyryl, dipropylaminostyryl, methoxystyryl, ethoxystyryl, methylstyryl, etc.), nitro group, hydroxy group, carboxyl group, cyano group, or substituted or unsubstituted arylazo group (phenylazo, α-naphthylazo, β-naphthylazo, diethylaminophenylazo, chlorophenylazo, nitrophenylazo) , methoxyphenylazo, tolylazo, etc.) q
c. Also, 1 (1, and 1 and 7 and L,
and I also, , l(,, and 1 and 1.1, and 1 and 1
j6. At least one combination of and forms a substituted or unsubstituted aromatic ring (benzene, naphthalene/, chlorobenzene, bromobenzene, methylbenzyl, ethylbenzene/, methoxybenze/, ethoxybenzene, etc.) 1 (・4 is a substituted or 1-substituted aryl group (phenyl, tolyl, xylyl, biphenyl, α-naphthyl, β-
Nafnal, a/tralyl, pyrenyl, methoxyphenyl, jetoxyphenyl, trimethoxyphenyl, ethoxyphenyl, jetoxyphenyl, chlorophenyl, dichloro7enyl, trichloronoenyl, bromophenyl, dibromophenyl, triflomophenyl, ethylphenyl , diethylphenyl, nitrophenyl, aminonoenyl, dimethylaminophenyl, diethylaminophenyl, dibenzylaminophenyl, siglopylaminophenyl, morpholinophenyl, piperidinylphenyl, hyherazinophenyl, diphenylaminophenyl, acetylaminophenyl, benzoylaminophenyl, acetylphenyl, pensoylphenyl, cyanophenyl, etc.). Or, I(,, is 7 di/, thionoene, benzo 7/, thionanthene, dibenzofuran, carbanol, phenothiazine, phenolic acid/, pyridino, etc., σ (from 4, S derived) and monovalent The heterocycle of Kolera represents an alkyl group (butyl, ethyl, II-propyl, inlopyl, n-butyl, t
-butyl, l-amyl, n-hexyl, n-ofnal,
2-ethylhexyl, t-ofnal, etc.), alkoxy groups (methoxy, ethoxy, furoboxy, methoxy, etc.)
, aryl group (phenyl, tolyl, quinolyl, ethylphenyl, methoxyphenyl, ethoxyphenyl, chlorophenyl, nitrophenyl, dimethylaminophenyl,
α-naphthyl, β-naphthylnato), amino groups (amine, dimethylamino, diethylamino, diethylamino,
acetylamino, benzoylamino C, etc.) may be substituted as a substituent.

In addition, Z0 in the formula is barchlorate, fluoroboret 1.
, sulfoacetate-1, iodide, chloride,
Anis-bromide, P-toluefsulfonate, alkylsulfonate, alkyldisulfone-1, benzene disulfoy L-1-, halosulfonate, viclate, tetofcyane eterenoaniono, tetracyanoquinodimethane anion, etc. The rest is next.

Below is book 9? 14 of azulenium salt compounds used in y-ming
Take the body and take it all the way to the bottom d pi.

02H.

ni() l13 (11) (12) (13) (14) C2+t.

C H3 (17) CJJ) C)il (20C211゜1', 3579-1', 3593 (1961)), an azuleno compound and a corresponding aldehyde compound are mixed in a suitable manner in the presence of a strong acid. Obtained by mixing in a solvent.

The reaction solvent used and L7 include alcohols such as ethanol, butanol and benzyl alcohol, nitriles such as acetonitrile and nitrobionitrile, organic calphones such as vinegar, acid anhydrides such as acetic anhydride, dioxa/, Alicyclic ethers such as tetrahydrofuran are used. It is also possible to mix aromatic hydrocarbons such as benzene with distilled butanol, benzyl alcohol, etc. The temperature during the reaction ranges from room temperature to boiling point.

Synthesis Example 1 (Chemical f8i product 1) P-dimethylaminobenzaldehyde 5.96 g, 70
% perchloric acid 10 ml and tetrahydrone 400 md
A liquid consisting of 1,4-dimethyl-7-itubrovir azuleno7.92! ! and tetrahydrofurano 400 mA
A solution consisting of the following was added dropwise at room temperature, stirred for 2 hours, and left in the apparatus overnight. Treating the precipitate, add tetrahydrofuran io
Wash filtration was performed three times with 0 mg. A little water 200
Washed and filtered twice with IT, and further added 1 liter of tetrahydrofuran.
After washing with 00 ml and drying, compound 4639 was added to 1
0.40g was obtained. (Yield 60.6%) Melting point: 1'60.5-162°C (capillary method) Solution absorption spectrum: λmax 6401m in acetone Elemental analysis: Molecular formula C2,H,8CANO.

Calculated value (To) Analysis value (To) C67,0467,17 H6,586,68 N 3.26 3.19 C18,258,16 Synthesis example 2 (Compound 12) P-dimethylaminobenzaldehyde 1.50 g, 70
% perchlorine m 5.0 rnA and vinegar Cfi, ] 50
mA! Azulene 1.28. ! A solution of 7 and 150 wJ of acetic acid was added dropwise at room temperature, and the mixture was stirred for 1 hour. The precipitate was filtered, washed with 100 ml of acetic acid, poured into 250 ml of water, stirred for 30 minutes, and filtered. Next, the mixture was washed and filtered seven times with 200 ml of water and then dried to obtain 2.41.9 of Compound 1650. , (yield 67.0%) Melting point: 260°C or higher (capillary method) Solution absorption spectrum: λmax 634 nm in acetonitrile Elemental analysis Molecular formula 〇+oH+s (-lNO*calculated value (total) Analysis value 00 C63,4264,58 1i 5.05 5.32 N 3.89 4.04 CJ 9.85 9.64 Synthesis example 3 (compound/l616) N~ethyl-3 in 160 ml of tetrahydro7 run
- formylcarbazole 2.267 and guaiazulene (
Aldrich Chemical Company #: 01,100-4)
2.0. ! After adding 9 and dissolving, 70 at room temperature.
Add 5.0rne of perchloric acid and heat until the liquid temperature reaches 60℃~
The reaction was carried out at 65° C. for 1 minute. Then cool it down,
-After standing for day and night, after separating the formed precipitate, 4oIn
Washing and filtration four times with 1 liter of tetrahydrofuran and drying yielded the crude product 3.37. IZ (roughness rate 66.2
%). Next, 0.9.7 of this crude product was recrystallized in a mixed solvent of methyl ethyl ketone and acetonitrile (methyl ethyl ketone:acetonitrile=8=5) to obtain 0.42 g of purified compound @A54.

Melting point = 206°C to 208°C (capillary method) Solution absorption spectrum (in chlormethane): λ max =
612 nm Elemental analysis Binary Molecular formula C5oHsoC1l N(JaC
1 model, I city (to) Analysis value (to) C71,4872, o4 H6,016,14 N 2,78 2. B□ C17,037,01 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 liquid crystal composition 108, a liquid crystal in which a compound represented by the aforementioned general formula (1) is dissolved is used. The liquid crystal used in the device of the present invention is suitably a smectic liquid crystal, particularly the A phase or C phase of a smectic liquid crystal having positive dielectric anisotropy.
phase is suitable.

Such smectic liquid crystal is arranged in a smectic phase of a homeotropic structure until it is locally heated by a laser beam, and as the temperature -L increases, the phase changes from the smectic phase of the homeotropic structure to the nematic phase to the intropic phase. Can change. Next, when the phase is changed from the isotropic 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 a liquid crystal element is locally heated to an isotropic phase by irradiation with a laser beam, and then rapidly cooled, that area becomes a smectic phase with a focal conic structure, and this state has light scattering properties. A still image pattern can be formed by scanning an optical signal using the laser beam described above.

Compounds capable of forming a smectine phase having positive dielectric anisotropy used in the liquid crystal element of the present invention include, for example, JP-A-5FI-150030 and JP-A-57-40429.
Compounds described in JP-A-57-51779 and the like can be used.

The compound represented by the aforementioned general formula (1) can be contained in the liquid crystal composition 108 in an amount of 0.1% by weight or more, preferably in the range of 1% to 3% by weight based on the liquid crystal.

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. It is suitable that the cholesteric liquid crystal is contained in the liquid 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 liquid crystals that can be used in the present invention include cholesteryl chloride, cholesteryl bromite, cholesteryl iodite, cholesteryl nitrate, cholesteryl chloridecanoate, cholesteryl butyrate, cholesteryl caprate, cholesteryl oleate, cholesteryl lylate, cholesteryl laurate, Examples include cholesteryl compounds such as cholesteryl myristate, cholesteryl heptyl carbamate, cholesteryl caprate, 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 intropic phase by local heating with a laser beam, and when this is rapidly cooled, a focal conical structure smectic phase changes as described above. can be formed.

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 isotropic 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. and 104
By applying an appropriate direct current or alternating current during the process and slow cooling, it is possible to cause a phase change from an intropic phase to a nematic phase to a smectinic phase. At this time, since the liquid crystal is in the nematic phase and has positive dielectric anisotropy, the nematic liquid crystal is aligned in the direction of the electric field, and a smectic A phase or C phase with a homeotropic structure is further formed to cool the written image. The pattern will be erased. Electrode 10
3 and 104 are generally obtained by a transparent conductive film of indium oxide, tin oxide, or ITO (Indium Tin Oxide), and if necessary, by a metal conductive film of aluminum, chromium, silver, or nickel. can get. This electrode 103 and lo4 are
It is desirable that the film be coated over the entire surface of the electrodes 102 and 102, and it is not necessarily necessary to have a predetermined pattern shape or matrix electrode structure. However, it is also possible to design a predetermined pattern shape or matrix electrode structure as desired.

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. These alignment control films 106 and 10
7 has a surface structure that allows the alignment direction of the liquid crystal composition 10B that contacts these critical surfaces to be controlled to a desired state. The alignment control films 10B and 107 also function as insulating films that can prevent the generation of current flowing through the liquid crystal composition 108. This kind of alignment control film 1
0B and 107 are, for example, silicon oxide, silicon dioxide, aluminum oxide, zirconia, magnesium fluoride, cerium oxide, cerium fluoride, silicon nitride, silicon carbide, boron nitride, polyvinyl alcohol, polyimide, polyamideimide, polyesterimide. , polyparaxylerin, polyester, polycarbonate, polyvinyl acetal, polyvinyl chloride, polyamide, polystyrene, cellulose resin, melamine resin, urea resin, acrylic resin, organosiloxane, polyethylene fluoride, and other insulating materials by vapor deposition or dip coating. It can be obtained by forming a film using a spinner coating method, a spinner coating method, or a spray coating method.

The alignment control films 106 and 107 homogeneously align the liquid crystal composition 108 by rubbing their surfaces with cloth, paper, velvet, etc., or by using an oblique thin coating method when forming the film, depending on a predetermined writing method. A silane compound having a surface structure or having a perfluoroalkyl group on the surface, for example, as described in JP-A-50-38150, JP-A-50-501
The liquid crystal composition 108 has a surface structure that homeotropically aligns the liquid crystal composition 108 by treating it with a compound such as an alkyltrialkoxysilane described in Japanese Patent Publication No. 147 or a tetraalkoxysilane described in JP-A-50-63955. I can do it.

The optimum film thickness of the orientation control 11910B and 107 varies depending on the type of insulating material used, but it is generally in the range of 100 A to 1 L, preferably 500 A to 20 A.
It is suitable to set the thickness in the range of 0 OA, and it is also desirable to set the film thickness so that the alignment control films 1013 and 107 also function as antireflection films.

In addition, the liquid crystal element of the present invention forms the above-mentioned still image by irradiating the laser beam 110 from the rear direction as shown in the figure, and uses observation light 109 such as natural light, halogen lamp light, noon lamp light, fluorescent lamp light, etc. from the front direction. The above-mentioned still image can be observed by making the light beam incident on the element and using this light beam as reflected light from the cold mirror 105. This cold mirror 105 generally has a sufficiently high reflectance for visible light and a high transmittance for light with a long wavelength of 600 cm or more. Specifically, G
e/MgF2 (1/'4 people) /CeO2 (1/4 people) /MgF2 (,1/4λ)/CeO2 (1/4 people)
A multilayer film consisting of

However, in the present invention, the use of cold mirror 105 can also be omitted. Further, in the element of the present invention, a cold filter (1Δ not shown) can be provided between the electrode 103 and the alignment control film 10B. This cold filter is
It has a sufficiently high transmittance 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 the above general formula (1), compound No. 1 was converted into a smectic liquid crystal (4,4'-
Cyanooctylbiphenyl (having positive dielectric anisotropy) was dissolved in a proportion of 2% by weight. At this time, after heating the liquid crystal composition until it becomes an introbic phase,
The above-mentioned compound was added, and this liquid was injected into a cell whose inner wall surface had been subjected to a homeotropic alignment treatment, and then slowly cooled to form a smectic phase liquid crystal having a homeotropic structure.

The laser oscillator 202 that emits the laser beam used to write an image on the liquid crystal cell 201 can be selected from those with wavelengths that correspond to the absorption efficiency of the above-mentioned compounds contained in the liquid crystal. A long wavelength laser beam emitted from a neon laser, a semiconductor laser, or a YAG laser, or a short wavelength laser beam emitted from an argon laser can be used. The laser beam emitted from the laser oscillator 202 is transmitted to modulators 203, 7. ') y 204, Y-axis deflector 2
05, the light passes through the X-axis deflector 206, is modulated and deflected, is focused by the writing lens 208, and is irradiated from the back surface of the liquid crystal element 201 via the graphical mirror 209. The aforementioned modulator 203. Y-axis deflector 205
The +, X-axis deflector 206 is connected to the signal source 211 via a driving amplifier 210, thereby controlling the laser beam and converting the digital electrical signal from the signal source 211 into an optical signal. An image pattern is written on the liquid crystal element 201 by this optical signal.

Thereafter, the Peltier element 212 attached to the peripheral part of the liquid crystal element 201 is activated by the electric current 213 to bring it into a rapid cooling state, cooling the liquid crystal element 201 to form a smectic phase with a focal conic structure, and irradiating the optical signal. An image pattern was formed in which the exposed areas were in a light scattering state. At this time, the temperature of the Venirtier element 212 is controlled by the temperature controller 214.

This image pattern can be observed by turning on the illumination source 215 placed in front of the liquid crystal element 201.

Next, in order to erase the above-mentioned image pattern, a transparent heater 216 (for example, an indium oxide film, a tin oxide film, an ITO film) provided on the liquid crystal element 201 is connected to a temperature controller 2.
The liquid crystal layer is heated by a heater power source 218 via a heater power source 218 to cause a phase change from a liquid crystal phase to an intropic phase. After that, while applying a voltage from the AC power supply 221 between the electrodes 219 and 220 provided on the liquid crystal element 201, the liquid crystal element 201
was slowly cooled to form a smectic phase with a homeotropic structure.

As a result, the written image pattern was erased.

The liquid crystal element of the present invention can be applied to a large screen display, and can also be applied to an optical disk system using a recording method in which pits are formed by scanning an optical signal containing predetermined information along a track. I can do it.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a liquid crystal element of the present invention. FIG. 2 is an explanatory diagram showing an example of a display method using the liquid crystal element of the present invention. +01. Io2; Substrate +03,104; Electrode 105; Cole 1ζ mirror 106.10? , alignment control film 108; liquid crystal composition 108; observation light +10; laser beam

Claims (1)

[Scope of Claims] A liquid crystal element comprising a liquid crystal composition containing a liquid crystal and a compound represented by the following general formula (1). General formula (1) (In the formula, It, , I is also 2, 1 is also 3.'' and 4+' are also 6
．． ji1. and 1 (1□ represents a hydrogen atom, a halogen atom, or a monovalent organic residue. It8 is substituted or unused.
1ζ1 represents a monovalent hydrogen atom group derived from a wide variety of aryl groups or substituted or unsubstituted heterocycles. Z represents an anionic residue. )