JPS63318526A - Liquid crystal optical element - Google Patents

Abstract

PURPOSE:To obtain an optical element which has a high response speed, is suitable for displaying moving pictures and is capable of making large-area display by using a stretched and oriented ferroelectric high-polymer liquid crystal having a chiral smectic C phase. CONSTITUTION:The stretched and oriented ferroelectric high-polymer liquid crystal which has the chiral smectic C phase and is held in place between two sheets of conductive films at least one of which is transparent. The number average mol.wt. of the high-polymer liquid crystal is preferably 2,000-400,000. An 'NESA(R)' film deposited with tin oxide, ITO film, etc., consisting of tin oxide and indium oxide, etc., are usable as the transparent conductive films. Since the excellent responsiveness as the display element is thereby provided to this liquid crystal display element, the displaying of the moving pictures is possible and the formation of the larger area element is easy.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a liquid crystal optical element suitable for large area display elements and the like.

[Conventional technology]

Conventionally, in order to display a large area, a method has been known in which small blocks such as CRTs and fluorescent display tubes are stacked to create a large area (Astro Vision, etc.), but the drive method is complex and requires an enormous amount of equipment. shall be. Furthermore, this method of arranging small blocks has the disadvantage that it is unsuitable for high-resolution displays because of the formation of connecting parts, and it is also unsuitable for displaying continuous patterns.

Therefore, a display element capable of displaying a large area is desired, and a display element using polymer liquid crystal has been proposed (Japanese Unexamined Patent Publication No. 10930/1983), but the response speed is slow and it is not suitable for displaying moving images. It wasn't something.

[Problem that the invention seeks to solve]

An object of the present invention is to provide an optical element that has a fast response speed to external factors, is suitable for displaying moving images, and is capable of displaying a large area.

[Means for solving problems]

The present invention relates to a stretched and oriented chiral smectic C sandwiched between two transparent conductive films, at least one of which is transparent.
The present invention relates to a liquid crystal optical element characterized by being made of a ferroelectric polymer liquid crystal having a phase.

In the present invention, a ferroelectric polymer liquid crystal having a chiral smectic C phase is used, so when the obtained optical element is used as a display element, it has a fast response speed to external factors and is suitable for displaying moving images. Become.

Various types of ferroelectric polymer liquid crystals having a chiral smectic C phase can be used, and specifically, the following are preferably used.

+1) Polyacrylate polymer liquid crystal Polyacrylate polymer and its copolymer having a repeating unit consisting of the following general formula is an integer up to and R
-C00R3, -0COR', -0R1, or -
R3, where 1 is +CHz)-C1l+CHz)y-CH:+, and R
4 is -CH or CI, m is an integer from 0 to 1o, n is an integer from 0 to 10, provided that R4 is -C
When H5, n is not 0. ) (2) Polysiloxane-based polymer liquid crystal Polysiloxane-based polymer and its copolymer S +0-Si+ (Cl ke-1-0-R' (in the formula, R% is represents a lower alkyl group, p represents an integer of 3 to 30, and R1 has the same meaning as above.) (3) Polyether polymer liquid crystal A polyether polymer having a repeating unit consisting of the following general formula and Copolymer thereof (wherein k and R1 have the same meanings as above) (4)
Polyester polymer liquid crystal Polyether polymer and its copolymer having repeating units consisting of the following general formula÷CH□-C-CHzOC(CHzhCO+C1l+C
Hz) KO-R' (wherein Rh is) IScI3 or CtHs, l is 1
An integer of ~20, k and R' have the same meanings as above. )
(5) The polymer liquid crystal in which the side chains are fixed to the main chain by hydrogen bonding may have one or more types of side chains.

The number average molecular weight of the polymer liquid crystal used in the present invention as described above (11 to (5)) is preferably 2.00.
0 to 400.000. If it is less than 2,000, the moldability of the polymer liquid crystal as a film or coating may be impaired, while if it exceeds 400°000, undesirable effects such as a slow response speed may appear. . The particularly preferable range of the number average molecular weight cannot be unconditionally defined because it depends on the type of substituent, etc., but 3.
000 to 200.000.

In addition, polymeric liquid crystals are made of ordinary resins such as olefin resins, acrylic resins, methacrylic resins, polystyrene resins, polyester resins, polycarbonate resins, styrene-butadiene copolymers, and vinylidene chloride-acrylonitrile copolymers. It is also possible to create a polymer liquid crystal film by mixing it with However, if a large amount of these resins is added, the liquid crystal properties will deteriorate, so it is preferable that the weight ratio to the polymer liquid crystal is 2 or less.

On the other hand, in order to improve the response, ferroelectric low-molecular liquid crystals, such as p-decyloxybenzylidene-p-amino-2-
A liquid crystal compound having a chiral smectic C phase such as methyl butyl cinnamate may also be used in combination. The mixing ratio is preferably 5 or less in terms of weight ratio.

Examples of methods for stretching the polymeric liquid crystal include methods commonly used for stretching plastic films, such as -axial stretching, biaxial stretching, press stretching, and inflation stretching. Among these methods, the uniaxial stretching method is preferably used. Also, roll coater, bar coater,
Coating and stretching can also be performed using a screen printing machine.

The stretching ratio is usually 30-1000%, preferably 50-60%
It is 0%. If the stretching ratio is less than 30%, the degree of orientation of the liquid crystal is low and a good contrast ratio cannot be obtained. Also, 1000
%, a continuous film cannot be obtained.

The polymer liquid crystal may be stretched by the polymer liquid crystal alone, or by sandwiching it between two plastic films. Alternatively, the polymer liquid crystal can be stretched by pressing the polymer liquid crystal sandwiched between transparent substrates.

At least one of the two conductive films sandwiching the ferroelectric polymer liquid crystal is a transparent conductive film. As the transparent conductive film, a NESA film coated with tin oxide, an ITO film made of tin oxide and indium oxide, etc. can be used. This transparent conductive film is preferably provided inside a transparent substrate made of glass or plastic (polymethyl methacrylate, polycarbonate resin, etc.). When the optical element of the present invention is used as a display element, it is preferable to provide a polarizing plate or a reflecting plate on the outside of the transparent substrate.

Examples of the opaque conductive film used when a transparent conductive film is not used include aluminum, gold vapor deposited films, sputtering films, and the like.

The optical element thus obtained is used as a display element and a memory element, and has excellent properties.

〔Example〕

Hereinafter, the present invention will be explained in detail based on Examples, but the present invention is not limited thereto.

In addition, in the following examples, the structure of the obtained polymer was determined by NMRSIR1 elemental analysis. The phase transition temperature was measured and the phase was confirmed using DSC and a polarizing microscope, respectively.

Further, the phase state of the polymer is indicated using the following abbreviations. (
Cry: crystal, Iso: isotropic liquid, SmA: smectic A-phase liquid crystal state, SmC'': chiral smectic C-phase liquid crystal state, SI: smectic liquid crystal state that is difficult to identify, Glass glass state) In addition, the numbers indicate the phase change temperature. It is expressed in °C.

In Examples 1 to 6, cases in which the polymeric liquid crystal compound of the present invention is used as an optical display element will be described.

Example 1 0.21 mol (14.8 g) of polymeric liquid crystal compound acrylic acid having a repeating unit represented by the following general formula and 0.23 mol (4 mol) of tetramethylammonium hydroxide (pentahydrate)
1.8 g) was stirred in 300 ml of DMF for 2 hours to make a homogeneous solution, 0.21 mol (77.4 g) of 1,12-dibromododecane was added, and the mixture was further stirred for 10 hours. Next, water 3001 was added to the reaction solution, extracted with ether, and purified by column chromatography to obtain 24.6 g of the desired bromoester (la) (yield 37%).
I got it.

0.29 mol (40.0 g) of p-hydroxybenzoic acid and 0.35 mol (S)-(-)-2-methylbutanol (
30.9 g) in the presence of 1 m Il of concentrated sulfuric acid and 150 mj of toluene! The mixture was refluxed for 20 hours. After concentrating the reaction solution,
Purified by column chromatography to obtain p-hydroxybenzoic acid 2-methylbutyl ester [[α]]. =+4
．． 95° (CHCI3)) 53.2g (yield 88%)
I got it.

(3) 4-Carbobenzoxyoxy p-
55 mmol (7,6 g) of hydroxybenzoic acid, 65 mmol (2,6 g) of sodium hydroxide in 200 m of water
65 mmol (10.6 g) of carbobenzoxy chloride was added dropwise to the aqueous solution under ice temperature.

After 24 hours, the precipitate was washed with water, filtered, dried, and purified by column chromatography to obtain 15.4-carbobenzoxyoxybenzoic acid. Og (yield 99%, m, p, 18
1.9-183.1°C).

27 mmol (7.3 g) of the above 4-carbobenzoxyoxybenzoic acid, 27 mmol (5.6 g) of phosphorus pentachloride
A solution of 50 mf of ether was stirred at room temperature for 24 hours. After the reaction, deetherification was performed, and the crystals were recrystallized from hexane to obtain 4-carbobenzoxyoxybenzoic acid chloride 4.5
g (yield 57%, m.

p, 65.5-67.4°C).

16 mmol (3.3 g) of the above p-hydroxybenzoic acid 2-methylbutyl ester in 20 ml of THF and 40 mt of pyridine! The solution was cooled, and a THF solution of 10 mmol (2.9 g) of the above 4-carbobenzoxyoxybenzoic acid chloride was added dropwise. Gradually return the temperature to room temperature,
Stir for hours. After the reaction, it was extracted with ether, concentrated, and purified by column chromatography to obtain 2.9 g of 4-(4'-carbobenzoxyoxybenzoyloxy)benzoic acid 2-methylbutyl ester (yield 63%, m, p, 54.
4-65.4°C).

An ethyl acetate solution of the above 2-methylbutyl nisterromole 4-(4'-carbobenzoxyoxybenzoyloxy)benzoate (2.8 g) and 0.5 g of palladium on carbon (5% catalyst) was added in a hydrogen gas atmosphere. After 4 hours of reaction, palladium carbon was filtered off using a membrane filter, concentrated and purified by column chromatography to obtain 4-(4'-hydroxybenzoyloxy).
1.26 g (yield 64%, m, p, 90.8-92.6°C) of benzoic acid 2-methylbutyl ester was obtained.

(7) 4-(4'-(12-acryloyloxide bucyloxy)benzoyloxy) P.O. 2-Methyl bromoester (la) 3.9 mmol (1.2 g)
and 3.3 mmol (1.1 g) of the above 4-(4'-hydroxybenzoxy)benzoic acid 2-methylbutyl ester.
and 15 mmol (2.1 g) of potassium carbonate in acetone was refluxed for 8 hours. After the reaction, filtration, concentration, purification by column chromatography, recrystallization with ethanol, and the desired monomer [[α]]. -+2.11@
(CHCl, )) 0.99 g (yield 53%) was obtained.

(8) ± 1.1 mmol (0.6 g) of monomer in a glass ampoule
, AIBNO, 26ag, and 2 ml of dry THF were added, and after freezing and degassing, the mixture was reacted at 60° C. for 15 hours. After cooling, the reaction mixture was concentrated and diluted with chloroform (20 ml
/g) and then purified by high performance liquid chromatography to obtain 0.3g of the target polymeric liquid crystal compound (conversion rate 50
%, Mn=5.300).

The above polymer was uniaxially stretched (250%) at 90° C. and lea/second to give a film thickness of 4 μm. This was sandwiched between glass substrates with transparent conductive films (ITO) patterned in advance to form a cell. The electrolytic response speed was determined in the temperature range showing phase transition behavior and ferroelectricity. The electrolytic response speed was measured by applying an alternating current electric field E=4×IQ'V/m and measuring the response time for a change in the amount of transmitted light (0-90%).

Phase transition behavior Example 2 0.15 mol (10.8 g) of a polymeric liquid crystal compound acrylic acid having a repeating unit represented by the following general formula and 0.15 mol (27 mol) of tetramethylammonium hydroxide pentahydrate
, 2 g) in 500 nl of DMF for 2 hours, and 0.23 mol (81
, 9g) and stirred for 4 hours.

300 mj of water in the reaction solution! Add ether extraction, drying,
After concentration, it was purified by column chromatography to obtain 32.3 g of the desired bromoester (lb) (yield 62.
%) was obtained.

13.9 mmol (4.8 g) of the bromoester (lb) obtained above and 3.3 mmol (4.8 g) of 2-methylbutyl 1-(4'-hydroxybenzoyloxy)benzoate obtained in Example 1. 4.4g) and potassium carbonate5
A solution of 3 mmol (7.4 g) in acetone was refluxed for 8 hours. After the reaction, filtration, concentration, purification by column chromatography, recrystallization with ethanol, and the desired monomer [[α]D=+2.26° (CHC13)
) 2.53g (yield 32%) was obtained.

(3)±Eni ■ Standing bottom monomer 1.0 mmol (0.60 g), AlBN2
．． After freezing and degassing 3■ and 9.5 ml of dry THF, the mixture was reacted at 60°C for 16 hours. After the reaction, it was concentrated, diluted with chloroform (20 mf/g), and purified by high performance liquid chromatography to obtain 0.35 g of the desired polymeric liquid crystal compound (conversion rate 58%, Mn-6,
500) was obtained.

Using the above polymer, electrolytic response speed was determined in the same manner as in Example 1 in a temperature range in which phase transition behavior and ferroelectricity were exhibited.

SmC" Response time 26°C, 0.04 seconds Example 3 A polymeric liquid crystal compound having a repeating unit represented by the following general formula II.

4.7 g of bottom 6-bromo-1-hexene, 6.3 g of 4-hydroxybiphenyl-4'-carboxylic acid 2-methylbutyl ester, and 3.1 g of potassium carbonate were refluxed in acetone for 20 hours. After the reaction, dichloromethane was added to dilute the reaction mixture, and inorganic substances were removed by filtration. The solvent was distilled off under reduced pressure, and the residue was purified by column chromatography to obtain the above 4-(7-hexenyloxy)biphenyl-4'-
6.4 g of carboxylic acid 2-methylbutyl ester was obtained (yield 79%).

(2) 4-(7-hexenyloxy)biphenyl-4'-carboxylic acid 2-methylbutyl ester obtained by Satomi Nijiki Shodon (1) 4
．． 0g and polymethylhydrosiloxane (Aldri
Made by ch company, no=1.3979, d=1.006, Mn
=2.900) was dissolved in 20 ml of toluene. Chloroplatinic acid hexahydrate 2■ was added as a catalyst, and the reaction was carried out at 80° C. for 24 hours under an argon atmosphere. After the reaction, reprecipitation was performed in methanol. After drying the obtained polysiloxane under reduced pressure, it was dissolved in dichloromethane and washed with water. The dichloromethane phase was collected and dried over magnesium sulfate, and then dichloromethane was distilled off under reduced pressure to obtain 1.5 g of the desired polymeric liquid crystal compound. (Mn=16.40
0) The above polymer was uniaxially stretched (500%) at 90° C. and 0.5 cm 2 /sec to give a film thickness of 2 μm.

This was sandwiched between glass substrates with transparent conductive films (ITO) patterned in advance to form a cell. The electrolytic response speed was determined in the temperature range showing phase transition behavior and ferroelectricity. The electrolytic response speed was measured by applying an alternating current electric field E = 4 x 10'V/m and measuring the response time for a change (0-90%) in the amount of transmitted light.

Response speed: 84° C., 0.3 seconds Example 4 A polymeric liquid crystal compound CH having a repeating unit represented by the following general formula.

In place of the 6-promo-1-hexene used in Example 3 (+), 5.1 g of 8-promo-1-octene was used,
Otherwise, the same operation as in Example 3 was carried out using the same substances as in Example 3 (1), that is, 6.3 g of 4-hydroxybiphenyl-41-carboxylic acid 2-methylbutyl ester and 4.0 g of potassium carbonate. , 8.1 g of the above 4-(7-octynyloxy)biphenyl-4'-carboxylic acid 2-methylbutyl ester was obtained (yield: 77%).

(2) 4-(7-hexenyloxy)biphenyl-41-carboxylic acid 2-methylbutyl ester obtained in (1) 4-(7-hexenyloxy)biphenyl-41-carboxylic acid 4
．． 0 g and 0.5 g of the polymethylhydrosiloxane used in Example 3 (2) were dissolved in 50 ml of toluene.

5 kg of chloroplatinic acid hexahydrate as a catalyst was added, and the reaction was carried out at 80° C. for 27 hours under an argon atmosphere. Thereafter, the same treatment as in Example 3 (2) was performed to obtain 2.1 g of the desired polymeric liquid crystal compound. (Mn=15,000) Response speed 80°C, 0.35 seconds Example 5 Polymer liquid crystal compound having repeating units represented by the following general formula (1) 4'-hydroxybiphenyl-4-carboxylic 4'
93 mmol (20 g) of -hydroxybiphenyl-4-carboxylic acid and 4 mmol (41 g) of (S)-(-)-2-methylbutanol were dissolved in 150 ml of benzene in the presence of 2 ml of concentrated sulfuric acid, while removing water. Refluxed for an hour. After concentrating the reaction solution, it was recrystallized from a toluene-hexane mixed solvent to obtain 26.0 g of the desired ester (
m, p, 116-117.8, [α)n=+4.35°
(CHC13)] was obtained. (Yield 98%) (2110-Chloro-1-decene) 10 drops of Schiff were added to 26.0 g of 9-decen-1-ol and placed in an eggplant flask. Under water cooling, 24.0 g of thionyl chloride was added dropwise. After the dropwise addition, the reaction was carried out at 70°C for 8.5 hours. After the reaction, it was diluted with dichloromethane and washed with an aqueous potassium carbonate solution. After drying over magnesium sulfate, it was concentrated under reduced pressure.

The residue was purified by column chromatography to obtain 10-
27.7 g of chloro-1-decene was obtained. (Yield 95%
) 2.5 g of lO-chloro-1-decene obtained in (2) and 6.5 g of sodium iodide were dissolved in 2-butanone,
Stirred at ℃ for 17 hours. After the reaction, it was diluted with dichloromethane and washed with water. After drying over magnesium sulfate, the solvent was distilled off under reduced pressure. To the residue were added 4.8 g of 4'-hydroxybiphenyl-4-carboxylic acid 2-methylbutyl ester obtained in step 11 and 2.4 g of potassium carbonate, and the mixture was reacted in 2-butanone at 80°C for 20 hours. After the reaction, inorganic substances were removed by filtration, concentrated under reduced pressure, and purified by column chromatography to obtain the desired biphenyl derivative 4.
．． 6g was obtained. (Yield 76%) (4) 3.0 g of the biphenyl derivative obtained in (3) and 1.5 g of m-chloroperbenzoic acid were dissolved in dichloromethane, the system was purged with argon, and then heated to room temperature. After the reaction was stirred for one day, the mixture was washed with an aqueous potassium carbonate solution and further washed with water. After drying over magnesium sulfate, the solvent was distilled off under reduced pressure to obtain 3.0 g of the desired monomer represented by the following formula. (Yield 97%) 0.5 g of the monomer obtained in (4) was dissolved in 5 m 12 of dichloromethane, and the system was purged with argon.

After 0.015 g of stannic chloride was added and a polymerization reaction was carried out at room temperature for 6 days, the reaction solution was poured into methanol.

The resulting precipitate was purified by repeating reprecipitation to obtain 0.4 g of the desired polymeric liquid crystal compound (yield 80%, Mn = 2,80
0) was obtained.

SmC" response time 45°C, 0.06 seconds Example 6 A polymeric liquid crystal compound having a repeating unit represented by the following general formula 12-dodecen-1-ol instead of 10-decen-1-ol
( of Example 5 except that 6.0 g of 1-ol was used)
The same operation as in 2) was performed to obtain 5.2 g (yield: 79%) of 12-chloro-1-dodecene.

12 obtained in (1) instead of 10-chloro-1-decene
The same operation as in Example 5 (3) was performed except that 5.2 g of -chloro-1-dodecene was used to obtain 8.8 g (yield 76%) of the desired biphenyl derivative.

(3) 8.8 g of the biphenyl derivative obtained in (2) above was subjected to the same operation as in (4) of Example 5, and 8.8 g of the monomer represented by the following formula (yield: 95%).

2.3 g of the monomer obtained in (3) was polymerized in the same manner as in (5) of Example 4, and 1.5 g of the desired polymeric liquid crystal compound (yield 65%, Mn = 3,200 ) was obtained.

Cry SmA ISO3mC" Response time 40°C, 0.05 seconds Examples 7 to 18 The polymeric liquid crystal compound of the present invention can be used as an optical display element using electric field response as in Examples 1 to 6, as well as using a semiconductor laser. It can also be used as a memory element.

FIG. 1 shows a cross-sectional view of an example in which the optical element of the present invention is applied to a memory element, and is created by disposing this polymer liquid crystal layer 1 between substrates 3 on which an ITO conductive film 2 is deposited. ing.

75 to 85 for the liquid crystal polymer used in Examples 1 to 6
℃, uniaxial stretching was carried out at the stretching ratio shown in Table 1 to give a film thickness of 4 μm. A semiconductor laser with a wavelength of 800 nm was used as a light source for writing into this memory element, and irradiation was performed with a beam focused to a beam diameter of 10 μm using an optical system. Table 1 shows the measurement results of the energy density required for writing.

The polymer liquid crystals used in Examples 1 to 6 are referred to as liquid crystals I to II, respectively.

Table 1 Example Liquid crystal Stretching ratio m1 (%) Energy density 09
I+ 100 19ion
200 1711 I[[10022 12III 200 1713 1V
100 2214 rV 200
1315 V 100 1
316 V 200 1417
Vl 100 1418 VI
200 121-th stretching rate 0 energy density is the power density of the light beam (unit: m J /
cj).

〔Effect of the invention〕

Since the liquid crystal optical element of the present invention has excellent responsiveness as a display element, it is possible to display moving images. Furthermore, it is easy to increase the area of the device, and it is extremely excellent as an information display device and a memory device.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a memory element made of a liquid crystal optical element of the present invention, in which 1 is a polymer liquid crystal layer, 2 is a transparent conductive film,
3 is a transparent substrate.

Claims (1)

[Claims] 1. A liquid crystal optical element comprising a ferroelectric polymer liquid crystal having a stretched and oriented chiral smectic C phase sandwiched between two conductive films, at least one of which is transparent.