JPS60118788A - Liquid crystal element - Google Patents

Abstract

PURPOSE:A liquid crystal element, having the composition in which a specific pyrylium compound is dissolved in a liquid crystal, and capable of forming optical signals corresponding to optical signals given from He-Ne laser, YAG laser, semiconductor laser or Ar laser. CONSTITUTION:A liquid crystal element containing a liquid crystal composition of a pyrylium compound of formula I [X is S, O or Ce; R1 and R2 are (substituted) aryl; R3 is (substituted) aryl or (substituted) heterocyclic ring; R4-R7 are H, halogen, alkyl or alkoxyl; n is 1 or 2; A<-> is anion], e.g. the compound of formula II, in an amount of preferably 1-3wt% dissolved in the phase A or C of preferably a smectic liquid crystal having positive dielectric anisotropy. USE:Optical disk systems of the recording method for forming a large scope display and pit.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a liquid crystal element that can be used in a thermal writing method.
More specifically, optical signals generated from laser beams, specifically helium-neon lasers, YAG lasers, semiconductor lasers, or argon lasers11. The present invention relates to a liquid crystal element that can form an optical image corresponding to the above.

Until now, liquid crystal devices have been used in which a 114-mer liquid crystal of a nematic liquid crystal with a negative dielectric anisotropy and a cholesteric liquid crystal or a smectic liquid crystal with a positive dielectric anisotropy is arranged between two glass substrates. 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 change the initial uniform orientation state 1. Random orientation L11.Ql different from Ql.
A liquid crystal phase of ; is formed. As a result, light 71 is scattered at the location where the laser beam is irradiated, resulting in a difference in optical properties between the liquid crystal phase and the uniformly oriented back region.

This type of liquid crystal element can also erase an optical image formed by laser writing using the method described above.

In other words, electrodes are provided on each of the two substrates that make up the liquid crystal element, and the liquid crystal phase is changed by heating the liquid crystal element (1°) with a heat source other than the laser beam (for example, a heater). It is heated to the isotropic phase, and then cooled with a voltage applied between the electrodes described above until, for example, a homeotropic structure is formed in the case of smectic liquid crystals, or a Grandshuan structure is formed in the case of cholesteric-nematic liquid crystals. By doing so, the optical image formed by the previous writing can be erased.

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 a computer terminal into optical signals, a laser beam has been modulated by a drive signal according to the digital image information, and this modulated laser beam is sent to an imaging lens, a galvanometer mirror, etc. A scanning method is adopted through an optical system consisting of a light deflector. 4. 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 less than 1 mm), the aforementioned liquid crystal elements have low heat conversion efficiency for long wavelength beams, and for this reason, when writing to liquid crystal elements using a semiconductor laser, high power is required. Laser beam irradiation was 8 yellow. However, semiconductor lasers generally have lower power than gas lasers such as argon lasers and helium-neon lasers, so even if the optical signal from an optical signal generator using a semiconductor laser is used to scan a liquid crystal element as described above, it is not sufficient. The disadvantage is 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 (If] 82), 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 type disclosed in British Publication No. 2091753. Furthermore, the above-mentioned liquid crystal element using a black dye has a drawback in that it does not provide good ergonomics display because both white image patterns are formed on a black background.

Therefore, it is an object of the present invention to overcome the aforementioned drawbacks and to
Another object of the present invention is to provide a liquid crystal element that can form an optical image pattern by scanning 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 pyrylium compound represented by the following general formula (1) is dissolved in liquid crystal.

General formula (1) In the formula, X represents a sulfur atom, an oxygen atom or a selenium atom.

几 and It2 are substituted or unsubstituted aryl groups (phenyl, α-naphthyl, β-naphthyl, tolyl, xylyl, methoxyphenyl, dimethoxyphenyl, chlorophenyl, bromophenyl, dichlorophenyl, dibromophenyl, trichlorophenyl, tribromophenyl ).

kLB is a substituted or unsubstituted aryl group (phenyl, α-naphthyl, β-naphthyl, anthralyl, pyrenyl, tolyl, xylyl, biphenyl, methoxyphenyl, dimethoxyphenyl/L/, ethoxyphenyl, jetoxyphenyl, amyloxy phenyl, nitrophenyl,
Dimethylaminophenyl, diethylaminophenyl, dipropylaminophenyl, dibenzylamine/phenyl,
Diphenylaminophenyl, hydroxyphenyl, chlorophenyl, dichlorophenyl, trichlorophenyl,
bromophenyl, dichlorophenyl, etc.) or substituted or unsubstituted cyclic groups (3-carbazolyl, 9-methyl-3
-Carbazolyl, 9-ethyl-J-rupazolyl, 7-
Nitro 9-ethyl-3-carbazolyl, 2-hyridyl, 4-pyridyl, 2-quinolyl, 4--1'/IJ
, 3-indolyl, 2-phenyl-3-inodolyl,
■-Methyl-2-phenyl-3-y/drill, etc.).几. , 几, It, JノYOHI 几, is a hydrogen atom,
Heroge 7 atoms (two atoms, a certain elementary atom, a fluorine atom,
Alkyl, Chill, B L7 Bill, Buburu, γ Mil, to”, Sil, A
methyl, /nyl group) or alkoxy group (methoxy,
n is 1 or 2.

However, when n is 2, l(, 4 may be the same <, and may be very different, and R may be the same or different, respectively.

Ae represents an anion such as barchlorate, fluoroborate, iodide, chloride, bromide, sulfate, bariodide, P-)luenesulfonate, etc.

Next, representative examples of the bi-IJ-IJ compound used in the liquid crystal element of the present invention represented by the general formula (υ) are shown below.

Compound point Compound example (υ Cl04 (l:) 3) 0 (261 (□□□ (30) (31) The biryllium-based compound used in the present invention is, for example, 2,6-
It is obtained by reacting diphenyl-4-methylthiapyrylium salt with 4-diethylaminobenzaldehyde. This reaction can be carried out in the presence of an amine or in a carboxylic anhydride.

1) When carried out in the presence of an amine. Various solvents are used as the solvent at this time, especially alcohols such as ethanol, nitriles such as acetonitrile, ketones such as methyl ethyl ketone, nitro compounds such as nitrobenzage, and halogenated compounds such as tetrachloroethane. Although hydrocarbons are used, alcohols such as ethanol are preferably used.

Examples of amines include primary, secondary and tertiary alkyl amines having 1 to 25 carbon atoms such as piperidine, triethylamine and hexylamine; aromatic amines having 6 to 25 carbon atoms such as anilyl and dimethylanili; /, quinoline and other nitrogen-containing unsaturated heterocyclic compounds are used.

The amount of amine is 0.1 to 1 mole of thiopyrylium salt.
10 mol is used, preferably 0.5 to 2 mol. It is also sometimes used in large excess as a sword/solvent.

The reaction time is preferably 30 minutes to 10 minutes, preferably 1 hour to 3 hours, and the reaction humidity is set at 50 DEG C. 0'iIf to the reflux temperature of the solvent or amino acid, preferably close to the reflux temperature. J of the bath is 1.1 to logic per 1 g of 26-diphenyl-4-methylthiopyrylium salt.

Preferably 3 to 10 ml is used.

II) When the reaction is carried out in m-water carboxylic acid.

l ''- for 1 g of carboxylic acid anhydride, for example acetic anhydride, 2,6-diphenyl-4-methylthiapyrylium salt.
20m7! , preferably 2 to 10 m1. Reaction time I
11 is 1 minute to 1 poem, preferably 3 to 20 minutes.

The reaction flow rate is from around 80°C to reflux temperature (140°C), preferably 100°C.

An example of synthesis of a typical biryllium salt used in the present invention will be shown.

Synthesis Example 1 (Byrylium of FiiJ exemplified Aα(23)) 5.0 g of 2,6-diphenyl-4-methylpyrylium verchlorate and 3.7 g of 4-diethylaminobenzaldehyde were mixed in 140 ml! of acetic anhydride at 95°C for 20
Heated for minutes. Next, leave it to cool and pass it through the sea. ^
'F, recrystallized from acid/anhydrous vinegar = L/11C,
I got Toryo 18y.

dense point, 271 to 272℃ Nine purple distribution j Molecular formula C, 7H,, O, NC6m calculated value (
%) Experimental value (%) C67,8568,01 H5,075,11 1 oxidation 2.93 2.88 Synthesis example 2 (thiopyrylium in deleted example (4)) 1.4 g of J6 (two-stage biryllium) was dispersed in 150 d of acetone, and a solution of 1 g of sodium sulfide dissolved in 10 + n7! of water was added and stirred for 2 minutes. 1 c of this solution was mixed with 1 bml of 20% perchlorine and 1 bml of water.
Add 50 mJH, stir for 1 hour, and release! It was 11. After the precipitate was filtered, it was recrystallized with acetic acid/fP water intoxication=l/1 to obtain dye #1.1.9.

Anger I point 277-2815°C Nine-dimensional formula Molecular formula C,, H2, U, NCl5it m
Value (%) Experimental value (%) C65,6465,88 J-14,914,84 86496,56 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 above-mentioned general formula (+) is dissolved is used. The liquid crystal used in the device of the present invention is smecti.

Smectic liquid crystals are suitable, and in particular phase A or C of smectic liquid crystals having positive dielectric anisotropy are suitable.

Such smectic liquid crystals have a homeotropic smectic structure until they are locally heated with a laser beam.
As the melon rises, it can undergo a phase change from the smectic phase of the homeomorphic structure to the nematic phase to the intropic phase. Next, when the phase is changed from the isodropinic sum to the smectic phase by quenching 11:, light scattering occurs. This results in the formation of a focal conic Mlm smedicine with a strong characteristic. 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 Ij) A normal image pattern can be formed by optical beam scanning using a laser beam.

Compounds capable of forming a smectic phase with positive dielectric anisotropy to be used in the liquid crystal element of the present invention include, for example,
f! Compounds described in JP-A-150030, JP-A-57-40429, JP-A-57-51779, etc. can be used.

The compound represented by the above-mentioned formula (1) is contained in an amount of 0.1% by weight or more, preferably 1% by weight to 3IT1.
It can be contained in the liquid crystal composition 108 in a range of IIi%.

Further, the liquid crystal element of the present invention may be a product obtained by combining a smectic liquid crystal having positive di-t anisotropy and a cholesteric liquid crystal. The cholesteric M crystal is in the liquid crystal composition 108 in a range of 0.5% to 15% by weight,
Preferably, the content is suitably in the range of 1% by weight to 5% by weight.

Cholesteric liquid crystals that can be used in the present invention include cholesteryl chloride, cholesteryl bromide, cholesteryl iotite, cholesteryl nitrate, cholesteryl chloroticaate, cholesteryl butyrate, cholesteryl caprate, cholesteryl oleate, cholesteryl oleate, cholesteryl laurate, cholesteryl Examples include cholesteryl compounds such as myristate, cholesteryl heptyl caroctamate, 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 the smectic phase of home-primary pink to the intro-pink phase by local heating with a laser beam, and when this is rapidly cooled, the smectic phase of the force-lukoninck structure changes as described above.・Can form a black phase.

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 are placed on the substrates +01 and 102 (for example, transparent glass plates or plastic plates such as acrylic plates) that constitute the liquid crystal element. By applying a suitable direct current or alternating current between +03 and 104 and slow cooling, a phase change from an isotropic phase to a nematic phase to a smectic phase can be caused. At this time, the liquid crystal is positive in the nematic phase! '[Because it has anisotropy'
Nematic liquid crystals are aligned in the horizontal direction, and a smectic A phase or C phase with a homeotropic structure is further cooled, and the written image pattern is erased. electrode +0
3 and 104 are generally indium oxide, tin oxide or ITO (Indium Tin O++1de).
It can be obtained by using a transparent conductive layer, and if necessary, it can also be obtained by using a metal conductive film such as aluminum, chromium, silver or nickel. These electrodes +03 and 104.

It is desirable that the pattern is patterned over the entire surface of the substrates +01 and 102, and it is not necessarily necessary that the pattern has a predetermined shape.
There is no need for a t-matrix electrode structure. However, it is possible to create a predetermined pattern shape or shape as desired.・It is also possible to design a refusumi extremely disaster-resistant structure.

The liquid crystal element of the present invention has an alignment control film made of an insulating material coating on the electrodes +03 and 104, respectively.
7 can be provided. The alignment control films 106 and 107 form a surface structure capable of controlling the alignment direction of the liquid crystal composition 108 that is in contact with these critical surfaces to a desired state. Further, the alignment control B*+oe and 107 also function as an insulating film that can prevent generation of current flowing through the liquid crystal composition 108. This kind of orientation control 11! ;! l0f (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 acecool, polyvinyl chloride,
It is obtained by forming an insulating material such as polyamide, polystyrene, cellulose resin, melamine resin, urea resin, acrylic resin, organosiloxane, polyfluorinated ethylene, etc. by vapor deposition, dip coating, spinner coating, or spray coating. It will be done.

The surfaces of the orientation control elements 106 and 107 are covered with cloth, paper, velvet, etc., depending on the predetermined writing method, or are diagonally steamed when forming the target 11Q. By using the i method, the liquid crystal composition 108 can have a surface structure with homogeous alignment, or the surface can be formed using a silane having a perfluoroalkyl group as described in JP-A No. 50-38150. Compound, Japanese Patent Application Publication No. 1973
Surface 4t' on which liquid crystal composition +08 is homeotropically aligned by treatment with a compound such as algyltrialkoxysilane described in Japanese Patent Publication No. 0-50947 or tetraalkoxysilane described in Japanese Patent Application Laid-Open No. 5043955. It can have an i structure.

The optimum thickness of the alignment control films 106 and 107 varies depending on the type of insulating material used, but generally it is 10.
Range from 0A to 1, preferably 500A to 200OA
It is suitable to set this orientation in the range of ff
It is desirable to set the film thickness so that the films 108 and 107 can also be used as anti-reflection films.

Further, the liquid crystal element of the present invention forms the above-mentioned still image by irradiating the laser beam +10 from the back surface as shown in the figure, and emits natural light, halogen lamp light, xenon lamp light, and Inno1 light ablation from the positive iMi direction. Observation light 108 such as
incident on the element, this ray is transferred to the cold mirror 10
The above-mentioned still image can be observed as anti-n4 light from 5. This cold mirror 105 is generally Df
It has a sufficiently high reflectance for visible light, and has a reflectance of 6 (10 no.
It has high transmittance characteristics for long wavelength light of n or more. Specifically, Ge/MgF2 (+/4λ) /C
ent (1/4 person) /MgF2 (1/4 person)/Ge
A multilayer film consisting of O2 (+/4 people) is known.

However, in the present invention, the use of cold mirror 105 can also be omitted. In addition, the device of the present invention connects a cold filter (not shown) to electrode +03 and orientation control 1]til
You can also put 89 between Ofl. This cold filter has a sufficiently high transmittance for 13f visible light and a sufficiently high reflectance for long wavelength light.

Next, FIG. 2 shows an example in which a display panel was formed using a liquid crystal element of undeveloped J.

+ii+ Among the compounds represented by the general formula (1) mentioned above,
Compound No. 5 was mixed with smectic liquid crystal (4,4'
- Cyanooctylbiphenyl (having positive electrolytic anisotropy) was dissolved in a proportion of % double. At this time, the liquid crystal composition is heated until it becomes an isotropic phase, the above-mentioned compound is added, this lα is injected into a cell whose inner wall surface has been subjected to homeotropic alignment treatment, and then slowly cooled. A smectic phase liquid crystal with a homeotropic structure was formed.

Is the laser oscillator 202 that emits a laser beam used to write an image on the liquid crystal cell 201 compatible with the absorption efficiency of the aforementioned compound contained in the liquid crystal? The laser I itself can be selected, but in particular the laser emitted from a helium-neon laser, a semiconductor laser or a YAG laser can be selected.
A long wavelength laser beam emitted by an argon laser or a short wavelength laser beam emitted by an argon laser can be used. The laser beam emitted from the laser oscillator 202 passes through a modulator 203, a slit 204, and a Y-axis deflector 20.
5. After passing through the Xil+l+ deflector 208 and being modulated and deflected, the light is focused by the writing lens 208,
The light is irradiated from the back side of the liquid crystal element 201 via the microink mirror 208. The aforementioned modulator 203, Y-axis deflector 205, and X-axis deflector 20θ are connected to the drive amplifier 21.
It is connected to the signal a211 via the signal source 2+1, which controls the laser beam and converts the digital electrical signal from the signal source 2+1 into an optical signal. An image pattern is written on the liquid crystal element 201 by this optical signal.

After that, the Peltier element 2+2, which has a 1-inch diameter and is attached to the periphery of the liquid crystal element 201, is activated by the electric current 11213.
The liquid crystal element 201 is cooled in a rapid cooling state.

A smectic phase of the focal conic M1 weave is formed, and the area irradiated with the optical signal becomes a light scattering state and ITj
An image pattern is formed. At this time, the Venirtier element 212 is temperature controlled by the temperature controller 214]
- Rolled.

This image pattern can be observed by turning on the illumination source 2+5 placed in front of the liquid crystal element 201.

Next, in order to erase the above-mentioned image pattern, the transparent heater 216 (e.g., indium oxide film, silver oxide film, ITO film) immersed in /I&crystalline/-201 is heated via the temperature controller +X217. for? [Source 2+8
is heated to cause a phase change from a liquid crystal phase to an isodropink phase. After that, ゛+L provided on the liquid crystal element 201
While applying a voltage from the AC power supply 221 between the E electrodes 219 and 220, the liquid crystal element 201 is slowly cooled, and the first
A smectic phase with a ropic structure was formed.

As a result, the written image pattern was erased.

The liquid crystal element of the present invention can be applied as a large screen display, and the liquid crystal element of the present invention can be used as a large screen display, and the liquid crystal element of the present invention can be used as a large screen display.
The present invention can also be applied to an optical disc system 1 using a recording method in which a focus is formed by scanning a number t along a track.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a liquid crystal element of the present invention. FIG. 152 is an explanatory diagram showing an example of a display method using the tth element of the present invention. 101.102. Board +03. +04; Electrode 105; Cold mirror IH, +07. Orientation control 1 model 108; Liquid crystal composition 108; Observation light 110: Laser beam Patent applicant Canon Co., Ltd.

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, or represents an unsubstituted multi-X ring group. R,,1(,, 几, and R7 represent a frozen candy atom, a hepgen atom, an alkyl group, or an alkoxy group. n h, l, or 2. however,
When n is 2, it may be the same or different, and R may be the same or different. A represents an anion. )