JPS60123582A - Liquid crystal element - Google Patents

Abstract

PURPOSE:To obtain a liquid crystal element capable of forming optical image corresponding to the optical signal given by He-Ne laser, YAG laser, semiconductor laser or Ar laser, by using a composition prepared by dissolving specific polymethyne compound in liquid crystal. CONSTITUTION:The objective liquid crystal element can be obtained by using a composition prepared by dissolving in (A) pref. A- or C-phase of a smectic liquid crystal having positive dielectric anisotropy (B) pref. 1-3wt% of a polymethyne compound of formula [R1-R5 are each H, (substituted) alkyl, (substituted) aryl, (substituted) styryl or (substituted) heterocycle; m is 0 or 1; n is 0-1; X<-> is anion]. USE:Optical disk system with such recording scheme as to form large-sized screen display or pit.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a liquid crystal element r that can be used in a thermal writing method.
The present invention relates to a liquid crystal element capable of forming an optical image corresponding to a light beam generated by a 3T laser beam 2, specifically a helium-neon laser, a YAG laser, a 1' conductor laser, or an argon laser. It is something.

Until now, we have used a liquid crystal element f in which a mixed liquid crystal of a neon laser with a negative dielectric anisotropy and a cholesteric liquid crystal or a smectink liquid crystal with a positive dielectric anisotropy is arranged between two glass substrates: @ j, 1. When this liquid crystal 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 orientation different from the initial uniform orientation. Ru. 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 manufactured using a laser ('
It is also possible to erase the optical image formed by t-imprinting. In other words, the liquid crystal element is constructed by providing electrodes on each of the two substrates, and using a heat source other than the laser beam (
For example, in the case of a smectic liquid crystal, the liquid crystal phase is heated to the isoI-ropic phase by heating the entire liquid crystal element with a heater), and then a voltage is applied between the electrodes described above. homeotropic tissue,
Alternatively, 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; it can form an image pattern simply by scanning optical signals converted from electrical signals, and the advantage is 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 corresponding to digital image information, and this modulated laser beam is passed through an imaging lens, A scanning method is employed in which the image is scanned through an optical system consisting of a light deflector such as 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 droplet crystal element f described above has a low heat conversion efficiency for long wavelength beams, so when writing to a liquid crystal element using a semiconductor laser, a high power is required. Laser beam! !
A sudden attack was needed. 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 can only 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 of I
nformation Display Intern
ational Symposium.

Digest of Technical Paper
"P, R34-49, 172-187.

238-253 (1982), 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 element of the method disclosed in Kazukai Kaikai No. 2091753. Moreover, the above-mentioned liquid crystal element using a black dye has a drawback in that a white image pattern is formed in a black background, which does not provide good display from an ergonomic point of view.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to eliminate the above-mentioned drawbacks and to 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. .

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

General formula (1) RI r R2 * R3+ "4 and R3 hydrogen atom or alkyl group (e.g. methyl group, ethyl group, D-propyl group, 1θO-propyl group, n-butyl group, eec
-butyl group, 1eo-butyl group, t-butyl group, n-amyl group, t-amyl group, n-hexyl group, n-octyl group, t-octyl group, etc.), and further includes other alkyl groups, such as Substituted alkyl groups (e.g., 2-hydroxyethyl group, 3-hydroxypropyl group, 4-hydroxybutyl group, 2-acetoxyethyl group, carboxymethyl group, 2-carboxyethyl group, ro-carboxypropyl group, 2-sulfoethyl group) , 3-sulfopropy/I/s, 4
-Sulfobutyl group, 3-sulfatepropyl group, 4-
Sulfatephthyl M, 1(-(methylsulfonyl)-
Carbamylmethyl group, 5-(acetylsulfami/L/
) propyl group, 4-(acetylsulfamyl)butyl group, etc.), cyclic alkyl group (e.g., cyclohexyl group, etc.), allyl group (OH,=CH-CH2), aralkyl group (e.g., benzyl group, phenethyl group, α-naphthylmethyl group, β-naphthylmethyl group, etc.), Iqkin・
All aralkyl groups (eg, carboxybenzyl group, sulfobenzyl group, hydroxybenzyl group, etc.) are included.

Furthermore, RI I R2+ R3r ``4 and R1 are i4 (deep or un) substituted arytes; , ethoxyphenyl group, dimethylaminophenyl group, diethylaminophenyl group, diethylaminophenyl group, dibenzylaminophenyl group, diphenylaminophenyl group), substituted or +d unsubstituted heterocyclic group (e.g. pyridyl group, quinolyl group) , lepidyl group, methylpyridyl group, furyl group, chenyl group, indolyl group,
virole group, carbazolyl group% N-ethylcarbazolyl group, etc.) and 11-substituted or unsubstituted sf IJ group (
Fallen tree grass, styryl group, methoxystyryl group, dimethoxystyryl group, trimethoxystyryl group, ethoxystyryl group, dimethylaminostyryl group, diethylaminostyryl group, diethylaminostyryl group, dibenzylaminostyryl group, diphenylaminostyryl group, 2.2 -diphenylvinyl group, 2-phenyl-2-methylvinyl group, 2-(dimethylaminophenyl)t, ) -2-phenylvinyl group, 2-(diethylaminophenyl)-2-
Phenylvinyl group, 2-(dibenzylaminophenyl)
-2-phenylvinyl group, 2,2-di(diethylaminophenyl)vinyl group, 2,2-cy(methoxyphenyl)
, 2 T 2 V (ethoxyphenyl) vinyl group, 2-(dimethylaminophenyl)-2-methylvinyl group, 2-(diethylaminophenyl)-2-ethylvinyl group, etc.). m is 0 or 1, and n is 0,1 and 1d2. 79 is chloride ion, bromide ion, iodide ion, perchlorate +4 ion, benzenesulfonate ion p-toluenesulfone m L
M represents an anion such as ion, methyl sulfate ion, ethyl sulfate ion, propyl sulfate ion, etc.

Next, representative examples of the polymethine compound represented by R2 represented by the general formula (1) will be listed.

Φ　− 〇 Sanya? ■.

Field δ ＼− Φ So S S S S ■.

\−□−111ノ Q　G’；　’:a　＜ S I OS □　＼−−□□／　＼− These polymethine compounds are Bernara S.

filrli et al.'s J, Am, Ohem, So (! (Journal of, American, Chemical Society)
8045772-5777 (195B) and HoSchm
Ann of idt et al.
Chemie) 623204-216 or RoWlzin
ger et al.) lern.

It can be easily obtained by synthesis using the synthesis method disclosed in, for example, Acta 24, 569.

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. As the axillary material used in the device of the present invention, a smectic liquid crystal product is suitable, and a smectic liquid crystal A phase or 1±C phase having positive dielectric anisotropy is particularly suitable.

Such smectic liquid crystals are arranged in a smectic phase with a homeolophic structure until they are locally heated by a laser beam, and as the temperature increases, the smectic phase of a homeolopic structure → nematic phase changes. →S is due to phase change to isotropic phase. Next, from the isotropic phase to the rapid cooling phase! When the phase is changed to a smectic phase using a molten metal, a smectic phase with a focal conic structure having light scattering properties is formed and destroyed. Therefore, when the smectic phase in the liquid crystal element is locally heated to the intropic phase by irradiation with a laser beam, and then rapidly cooled, the area becomes a smectic phase with a focal conic structure, and this state has light scattering properties, so A still image pattern can be formed by optical I/H scanning using a laser beam.

Compounds capable of forming a smectic phase having positive dielectric anisotropy to be used in the liquid crystal element of the present invention include, for example,
Compounds described in JP-A No. 13-150030, JP-A-57-40428, JP-A-57-51779, etc. can be used.

The compound represented by the above general formula (1) is contained in the liquid crystal composition 10'8 in an amount of 0.1% by weight or more, preferably 1% to 1% by weight, based on the liquid crystal. It can contain.

Further, the liquid crystal element of the present invention can also use a combination liquid crystal of a smectyl liquid crystal and a cholesteric liquid crystal having positive dielectric anisotropy. Cholesterlink LCD is LCD i&I
0.5% by weight to 15% in one compound! TI: It is suitable to contain it in a range of % by weight, preferably in a range of 1% by weight to -5% by weight.

Cholesterin liquid crystals that can be used in the present invention include cholesteryl chloride, cholesteryl bromite, cholesteryl iodite, cholesteryl nitrate, cholesteryl butyrate, cholesteryl carbureate), etc.
cholesteryl ole I, cholesteryl ole I,
Cholesteryl laurate, cholesteryl myriste I.
Examples include cholesteryl compounds such as cholesteryl heptyl rubberme), cholesteryl decyl ether, cholesteryl lauryl ether, and cholesteryl oleyl ether.

In an oil leakage element using such a liquid crystal, a phase change occurs from a primary pink smectic phase to an intropic phase due to local heating by a laser beam, and when this is rapidly cooled, a focal conic phase occurs as described in IIIf. It is possible to form a smectic structure of the tissue.

The liquid crystal element recorded by the above-mentioned method is produced by subjecting the entire surface of the liquid crystal Mll still life 08 to an intropic phase using, for example, a heater, and then converting the liquid crystal element to substrates 101 and 102 (for example, transparent). Electrode 103 and IQ provided on a plastic plate (glass plate, acrylic plate, etc.)
By applying a suitable direct current or alternating current during step 4 and slow cooling, a 411 change from iso]ropicui 11 to nematic 411 to smectin 711.1 can be caused. At this time, since the liquid crystal has a positive dielectric anisotropy in the nematic phase, nematic axillary crystals are aligned in the direction of the electric field, and a smectic A phase or C phase with a homeotropic structure that is further cooled is formed. The written image pattern is erased. Electrodes 103 and 104 are typically made of indium oxide, tin oxide or lf I T O (I
ndlum Tln Ox1de), and if necessary, gold such as aluminum, chromium, silver or nickel. Obtained by % conductivity 1 grass.

This 1 [4 transmission +03 and 104 are board 101 and 102
It is desirable that the film be coated over the entire surface of the electrode, and there is not necessarily a predetermined pattern shape or a center spacing for forming a matrix electrode structure. However, it is also possible to design a predetermined pattern shape or matrix electrode structure as desired.

In the liquid crystal element of the present invention, an alignment control film 106 made of an insulating material 11M is applied to each electrode 103 and 104.
and 107 can be provided. This orientation control film 10
6 and 107 are liquid crystal compositions 1# that are in contact at these critical surfaces.
It has a surface structure that allows the arrangement direction of 108 to be controlled to a desired state. The alignment control films 106 and 107 also function as an insulator that can prevent the generation of current flowing through the liquid crystal composition 108. This type of alignment control films 106 and 107 are made of, for example, -silicon oxide,
Silicon dioxide, aluminum oxide, zirconia, magnesium oxide, cerium oxide, cerium fluoride, silicon nitride, silicon carbide, boron nitride, polyvinyl alcohol, polyimide, polyamideimide, polyesterimide, polyparaxylerin ,polyester,
Polycarbonate-1, polyvinyl acecool, poly'X
Film formation using insulating materials such as vinyl acetate, polyamide, polystyrene, cellulose resin, melamine resin, urea resin, acrylic resin, organosiloxane, polyfluorinated ethylene, etc. by vapor deposition, dipping@cloth method, spinner coating method, or spray coating method. obtained by doing.

The orientation control 11+≧106 and 107 can be performed by rubbing the surface with cloth, paper, velvet, etc., or by using the diagonal coating method 7 for film formation 111, according to a predetermined old-fashioned formula. The composition 108 may have a surface structure that homogeneously aligns the composition 108, or the surface structure thereof may be described, for example, in Japanese Patent Application Publication No. JP-A-1-1-25030.
The silane compound having a perfluoroalkyl group described in JP-A No. 150, the alkyltrialkoxysilane described in JP-A No. 50-50947, and the silane compound having a perfluoroalkyl group described in JP-A No. 50-50947.
By treating with a compound such as tetraalkoxysilane described in No. 0-83955 +17,
Table r for aligning the liquid crystal composition 108 with homeo-i-lopink alignment
It can have an f8 structure.

Orientation control 11! For JIOe and 107, the optimum I+center/zo differs depending on the J+Ii IA of the insulating material used, but it is generally suitable to set it in the range of 100A-1, preferably in the range of 500A to 2000A. Furthermore, it is desirable to set the film thickness so that the orientation control films +08 and 107 also function as foul prevention 11W.

Further, the liquid crystal element of the present invention forms the above-mentioned still image by irradiating the laser beam 110 from the back side as shown in the figure, and allows observation of natural light, halogen lamp light, xenon lamp light, fluorescent lamp light, etc. from the front side. Light 109 element-
The above-mentioned still image can be observed by using this light beam as reflected light from the cold mirror 105. This cold mirror 105 has a sufficiently high reflective material for visible light on clothing, and has a diameter of 600 mm or more.
It has high transmittance characteristics for long wavelength light. Specifically, Ge/MgF2 (1/4 person) /CeO2
(1/4 person) /MgF2 (1/4 person)/CeO2 (1
/4 people) is known.

However, in the present invention, the use of the cold mirror 105 can be omitted. In addition, the element lOcold filter (not shown) of the present invention was used with electric J@103 and self-distribution control (JI
It can also be provided between the II odor 106. This cold filter has an extremely 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.

Compound No. 2 of the compound represented by the above general formula (1) is double-coated with smectic phase crystal (4,4'-cyanooctylbiphenyl; has positive dielectric anisotropy). %. At this time, the liquid crystal composition is heated until it becomes an isotropic phase, the above-mentioned compound is added, and this liquid is poured into a cell whose inner wall surface has been subjected to a homeotropic pink alignment treatment, and then slowly cooled. A smectic phase liquid crystal with a hono-first-ropink Mi weave was formed.

The laser generator 202 that emits the laser beam used to write an image on the liquid crystal cell 201 can be selected from wavelengths corresponding to the absorption efficiency of the above-mentioned compound contained in the crystal. In particular, a long wavelength laser beam emitted from a helium-neon laser, a semiconductor laser or a YAG laser, or a &i7 wavelength laser beam emitted from an argon laser can be used. The laser beam emitted from the laser oscillator 202 is transmitted to a modulator 203, a slit I/204, and a Y deflector 2.
05, the light passes through the X-axis deflector 206, is modulated and deflected, is directed by the writing lens 208, and is irradiated from the back of the liquid crystal element 201 via the tychroic mirror 209. The aforementioned modulator 203. Y-axis deflector 205
, X+li1+ deflector 206 is a driving amplifier 210
The signal source 211 is connected to the signal source 211 through which the laser beam is controlled and the digital electrical signal from the signal source 211 is converted into an optical signal. An image pattern is written on the liquid crystal element 20+ by this optical signal.

After that, the Bertier element 212, which was located around the liquid crystal element 201, is activated by the power supply 213, and is rapidly cooled! As E, the liquid crystal element 20+ was cooled to form a smectic phase of a Δ-chalconic structure, and an image pattern was formed in which the portions irradiated with the optical signal were in a light scattering state. At this time, the temperature of the Venirtier element 2+2 is controlled by the temperature controller 2+4.

This image pattern can be observed by turning on the illumination 1; f215 arranged in front of the liquid crystal element 201.

Next, in order to erase the above-mentioned image pattern, a transparent heater 218 (for example, indium oxide film, tin oxide film, ITOII mulberry film) provided on the liquid crystal element 201 is turned on by a heater power source 218 via a temperature controller 217. Heating causes a phase change from the liquid crystal phase to the isototropic phase.

After that, the 'if poles 213 and 2 provided on the liquid crystal element 201
The liquid crystal element 201 was slowly cooled while applying a voltage from an AC power source 221 for 20 hours to form a smectic phase having a homeo-I-ropic structure.

As a result, the written image pattern was erased.

The liquid crystal element of the present invention can be widely used as a large screen display, and can also be used in an optical display system that uses a recording method in which pits are formed by scanning an optical signal containing predetermined information along a trunk. It can be applied.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a liquid crystal element of the present invention. FIG. 2 is an explanation 1Δ showing one example of a display method using the liquid crystal element of the present invention. 101, 102. (Plate 103, +04; %: Pole 105; Cold mirror 10θ, 107; Orientation control film 108; Highest composition 108; Observation light 110, Laser beam Patent applicant Canon Co., Ltd. Agent Gi Marushima - 's Bu? -109'>1t.

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) (wherein, RI r R2r R3+ R4 and R6, hydrogen atom, monosubstituted or unsubstituted alkyl group, substituted or unsubstituted aryl group, substituted or unsubstituted styryl group, or 14 Indicates a substituted or unsubstituted heterocyclic group, m is 0 and 1, and n is 0, 1 or 2. X8 is an anion.)