JPS59184276A - Liquid crystal display element - Google Patents

Abstract

PURPOSE:To provide a quest-host liquid crystal display element which has a long service life and high contrast, by using a liquid crystal compsn. contg. a specified anthraquinone dichroic dye (yellow). CONSTITUTION:A dichroic dye of formula I [wherein R is alkyl, aralkyl, cyclohexyl, -CO-R1 (wherein R1 is alkyl, aralkyl, aryl, cyclohexyl)] such as a yellow dye of formula II is used. The dichloric dye is blended with a nematic liquid crystal such as 4-cyano-4'-n-pentylbiphenyl or 4-cyano-4'-n-propoxybiphenyl. The resulting liquid crystal 4 is interposed between a pair of glass sheets 1, each provided with a transparent electrode 2, thus forming a transmission type liquid crystal display element (numeral 3 is spacer, 5 is power source, 6 is incident light, 7 is observer, 8 is deflecting plate).

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a liquid crystal display element characterized in that it uses a 10-crystalline composition containing a dichroic dye.

Currently, calculators, watches, etc. that use twisted nematic type liquid crystal display elements are made into parts, but those that use twisted nematic type liquid crystal display elements: ■ Because they use polarizing plates,
In the case of a reflective type display that uses ambient light and a color light control plate, it has drawbacks such as a dark display and a narrow viewing angle.

In addition, display elements using the guest-host effect in which dichroic dyes are added to liquid crystals (1) do not necessarily require polarizing plates, so bright reflective color displays are possible; ■ Selection of dyes to be added; It has the characteristics of displaying a wide variety of colors, and if it is an internal illumination type (transmission type) using a polarizing plate, it is possible to display surface brightness and tube contrast. This is a display device that can adapt to the diversity of the recent market. However, conventional guest-host liquid crystal display devices do not fully satisfy both contrast and lifespan.

The reason for this is that conventional dichroic dyes did not have excellent properties in both dichroism and light resistance. Conventional dichroic dyes are mainly foam azo and anthraquinone yarns! It is known for many times. Azo type materials generally have a dichroic ratio of 8 to 10 and a light emitting life of several thousand hours, which is generally a high dichroic ratio, but a short emitting life. On the other hand, anthraquinones generally have a dichroic ratio of 6 to 9 and a light lifespan of several tens of thousands of hours [1], which is a sufficient light lifespan, but only a low dichroic ratio.

The present inventors studied dyes for display devices that utilize the L guest-host effect, and as a result, they found a dye with excellent dichroic ratio and light resistance, and completed the present invention.

That is, an object of the present invention is to provide a guest-host type 7 crystal display element that uses a dichroic dye that is excellent in both dichroism and light resistance, has simple contrast, and has a long life.

That is, non-inventiveness requires that at least one of a pair of
In a liquid crystal display system formed by disposing a liquid crystal composition between electrode substrates, the liquid crystal composition 1]i] is expressed by the following general formula (1).
) [In the formula, R1 represents an alkyl group, an aralkyl group, a cyclohexyl group, or a -GO-R group, and R1 represents an alkyl group, an aralkyl group, an aryl group, or a cyclohexyl group.

In the substituents of R and RX, the alkyl chain and aryl ring may be Mm. ] This is a liquid crystal display element characterized by using a liquid crystal composition containing one or more kinds of yellow pigments.

The dye used in the present invention is generally synthesized as follows. In other words, as shown in the disfavored reaction formula, the general formula ([
When the alkylating agent represented by the compound number represented by + (general formula QJI) is allowed to act on the presence of the deoxidizing agent -b, a yellow dye represented by the general formula (Il) is obtained.

01-I U OH [In the formula, l ( has the above-mentioned meaning.
f1. group, represents an acid oil or a hydrate residue. ] Here, the general formula (Il) includes methyl group, ethyl group, propyl group, butyl group, amyl group, hexyl group, octyl group, nonyl group, dodecyl group, etc.
or a branched alkylmethoxypropyl group, ethoxypropyl group, propoxyethyl group, butoxyethyl group, octoxyethyl group, ethoxyethoxyethyl group or a branched alkoxyalkyltylbenyl group. to xylphenethyl, P-phthoxybenzyl group, P-chlorobenzyl group, aralkylohexyl group such as pencil group, acetyl group, ethylcarl group, furoyl sulfonyl group, phthylcarbonyl group, pentylcarbonyl group, hexylcarbonyl group, octyl group Straight-chain or branched alkyl groups such as dodecylcarbonyl, dodecylcarbonyl, propoxymethylcarbonyl (such as straight-chain or branched alkyl), P-methoxybenzylcarbonyl, group, aralkyl sulfonyl group such as pencylcarbonyl group, P-methylbenzoyl group,
P-ethylben')ylno&, P-methoxybenzoyl group, l)-menalthiohensoylnok, P-ethylbenzoyl group, benzoyl group, P-propylbenzoyl group, ■)-butylbenzoyl group, P- Typical substituted iA include hexylbenzoyl group, P-butoxybenzoyl group, p-hexyloxybenzoyl group, P-chlorobenzoyl group, P-phenylbenzoyl group, arylcarbonyl group, cyclohexylcarbonyl group, etc. can give.

Next, he explained the non-invention in detail to the river using drawings.

I will clarify. FIG. 1 is a schematic cross-sectional view showing an example of a transmission type liquid crystal display device containing a 7-day display element of the present invention, and FIG. This is a schematic cross-sectional view. In Figure 1-2, l is a transparent glass substrate, 2 is a transparent electrode such as indium oxide provided inside the transparent glass substrate, and 3 is a spacer made of, for example, a Teflon film. , this makes the cell stiffness 10-2
4 is a nematic liquid crystal composition containing a dichroic dye, and 5 is a power supply applied to the element, and direct current or alternating current is used. 6 is incident light, 7 is the viewer's eyes, 8 is a polarizing plate, and 9 is a light scattering plate. In this device, the surface of the transparent electrode is treated by rubbing one side with a cotton cloth or the like, or by obliquely depositing silicon oxide, etc., so that the liquid crystal and dichroic dye are aligned parallel to the surface of the transparent electrode. ing.

The nematic liquid crystal exhibiting positive dielectric anisotropy used in the present invention has a general formula C in which one of R2 and Rq is a cyano group, and the other is an alkyl group, an alkoxy group, an alkoxyphenyl group, or an alkoxyphenyl group. represent. ] Single substances or mixtures of these substances can be used.

Figure fJ'J1 shows a transmissive display device, but the second
(An anti-@ type display device like evil is fine.)

In this case, a light scattering plate 9 is provided behind the panel.

Although a display device has been shown in which the color disappears when the αL1 voltage is applied, it is possible to construct a display device that exhibits a color when a voltage is applied.

In other words, a nematic liquid crystal exhibiting dielectric anisotropy is used as a 7-crystal, and the transparent surface is N.

Hedimethyl-to-octadecyl-3-aminopropyltrimethoxysilyl chloride, dimethyldichlorosilane, or methyltrichlorosilane, etc. treated with a host agent, or incorporation of tiltrimethylammonium fluoride blue into crystals. agent to coat the surface of the transparent electrode with liquid crystal and dichroic dye. '+
The display device can be constructed by rotating the display device.

In addition, when a small amount of cholesteric liquid crystal or chiral nematic liquid crystal is mixed with nematic liquid crystal, the display element becomes a so-called phase transition type (or White Tiller type) guest-host effect, and a polarizing plate is not required. High contrast can be obtained even with reflective type.

Next, examples of synthesis of typical dyes used in the present invention will be described.

Synthesis Example 1 (Compound 11) 1.2.7.8-Tetrahydroxyanthraquinone2.
7 parts of potassium carbonate, 1.4 parts of potassium carbonate, and 46 parts of n-hexyl iodide were placed in 20 parts of N,N-dimethylformamide, stirred at 80 to 90°C for 4 hours, and then poured into 200 parts of water. The precipitated crystals are separated by ρ, washed with water, and dried.

This crude product was crystallized from toluene-methanol to obtain 0.8 parts of a yellow dye having the following structural formula.

Synthesis Example 2 (Compound Tiger 2) 1.2.7.8-Tetrahydroxyanthraquinone 2.
7 parts and 1.4 parts of potassium carbonate.

Place in 20 parts of N-dimethylformamide and add 10 to 20
3.1 parts of P-methylbenzoyl chloride was added to C, and after stirring at the same temperature for 5 hours, it was poured into 200 parts of water, and the precipitated crystals were separated from P, washed with water, and dried. This crude product was recrystallized from toluene-methanol to obtain a yellow dye with the above structural formula. Synthesis Example 3 In place of 4.6 parts of n-hexyl iodide in Synthesis Example 1, 33 parts of diethyl sulfate and P-toluenesulfone p
n-octyl ester 6, 1 part, benzyl bromide 3
．． The following compounds /fi 3 to 6 were obtained in the same manner as in Synthesis Example 1 except that 7 parts or 3 parts of n-phthyl iotide were used.

/15.3 m, P, 181-184℃ &, 4 m, p, 105-107℃ High 5th grade 'T1. I), 197-200℃ ifo, 6 OFIOOH The dyes synthesized in this manner are shown below.

Point 7 01■0　　0to1 0H(JOH 11tr, 9 01=i 0 011 ot-t　　　oh OHOOH 612 sea 18 0H00l-1 tEr, l 4 Next, the present invention will be explained in detail with reference to examples.

Example A liquid crystal cell treated so that the liquid crystal and the dichroic dye were parallel to the electrodes was treated with 43% of 4-cyano4/-n-pentylbiphenyl, 17% of 4-cya/-4'-n-propoxybiphenyl, 4-cyano-4'-n-pentoxybiphenyl 13%, 4-cyano-4/-〇-octoxybiphenyl 17%, 4-cyano-4'-n-pentylterphenyl XO% (7) 71t crystal Compound (Es, BDL
- I Chemicals) and the above 1P.
A liquid crystal composition containing 1% of dye No. 01 was added.

When a pressure of about 6 volts is applied to the liquid crystal display element, the liquid crystal cell changes from yellow to almost colorless.

λInaX of dye No. 1 in aqueous liquid I~^ table hydrogen atoms is 4
At 55 nm 1), the light resistance of this liquid crystal display element was very good.

Example 2 In Example 1, : fo, jb instead of dye 1,
2. Seed 3. The procedure was the same as in Example 1 except that dyes of Shi41, Den5, or Uo6 were used, and when a voltage was applied to the cell, the cell changed to almost colorless.

λn1aX of each dye in this liquid crystal is 424n
m, 455. , nm, 455nl, 450nm.

455 nm, and the light resistance of this liquid crystal display element was very good.

Example 3 Dielectric W was applied to a liquid crystal cell subjected to vertical alignment or parallel alignment treatment.
Add 10% cholesteryl chloride (by weight) to the nematic ＾C・Es of the city.
A product composition prepared by dissolving 1% of the dye indicated by mark 1 /al was injected into the mixed liquid crystal to which 5.5% was added. In the configuration shown in Figure 2,
This liquid crystal display element turns yellow when pressure is applied;
When a voltage of about 5 cm or higher was applied, the display became colorless, and a bright, high-contrast inverted display was obtained without using a polarizing plate. In addition to the above-mentioned cholesteryl chloride, cholesteryl derivatives, and chiral nemate ink such as hypohenyl or ester-based cholesteric liquid crystal materials can be used for the mixed liquid crystal.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view of a transmissive liquid crystal display device using a product display element according to an embodiment of the present invention, and FIG. 2 is a schematic cross-sectional view of another embodiment of the present invention. 1 is a schematic cross-sectional view of a reflective liquid crystal display device according to an example. In Figure 1.2, 1......Glass plate, 2...
・Transparent base pole, 3・・・・・・・・・Spacer, 4
......Liquid crystal composition, 5...
Power supply, 6......Incoming light, 7...
...Viewer, 8...Polarizing plate, 9...
...It is a light scattering plate. Figure 1 Figure 2

Claims (1)

[Scope of Claims] A liquid crystal display element comprising a liquid crystal composition filled between a pair of electrode substrates, at least one of which is transparent, wherein one or more yellow pigments represented by the following general formula ([) are used as the liquid crystal composition. A liquid crystal display element characterized by using a liquid crystal composition containing two or more layers. Flo 0 0H [wherein R represents an alkyl group, an aralkyl group, a cyclohexyl group, or a -CO-R group, and R1 represents an alkyl group, an aralkyl group, an aryl group, or a cyclohexyl group. 1 (, R, where 8 is optional, and the alkyl chain and aryl ring may be substituted.)