JPS5893778A - Liquid crystal display element - Google Patents

Abstract

PURPOSE:To provide a guest-host type liquid crystal display element exhibiting excellent dichroism and light-resistance and high contrast and having an extended service life, prepared by filling a liquid crystal compsn. containing a specified yellow coloring matter between a pair of electrode plates one or both of which are transparent. CONSTITUTION:The liquid crystal display element is prepared by filling a liquid crystal compsn. which contains a yellow coloring matters of formulaI(where R1 is alkyl, alkoxyl, aralkyl, aralkyloxy, aryl, aryloxy or cyclochexyl; R2 is alkyl, aralkyl, aryl or cycloalkyl) between a pair of electrode plate one or both of which are transparent. The nematic liquid crstal which positive dielectric anisotropy includes monomers of substances of formula II-V (where R3 is cyano and R4 is alkyl, alkoxyl, alkylphenyl or alkoxyphenyl or vice versa) or a mixt. thereof.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a liquid crystal display element specially designed to use a liquid crystal composition containing a dichroic dye.Currently, calculators and watches using twisted nematic liquid crystal display elements have been commercialized. However, in the case of using a twisted or nematic type liquid crystal display element, the display is dark in the case of a reflective type that uses ambient light and a color display that uses a color polarizing plate because it uses a polarizing plate. The drawback is that the viewing angle is narrow.

In addition, display elements that utilize the guest-host effect by adding dichroic dyes to liquid crystals do not necessarily require polarizing plates, allowing for bright reflective color displays; Variety of colors, wide viewing angle, etc.%
- If you use a polarizing plate and use an internal illumination type (transmission type), it will be possible to display high brightness, high contrast, and contrast, making it adaptable to the diversity of the recent market. ◎However, conventional guest-type liquid crystal display elements have not been able to fully satisfy both contrast and lifespan.The reason for this is that conventional dichroic dyes are not dichroic. This is because they did not have excellent light resistance or light resistance.As conventional dichroic dyes, azo and anthraquinone dyes are mainly known. Azo type generally has dichroic ratio l
~/θ, the emitted light lifetime is several thousand hours, and the dichroic ratio is high, but the emitted light lifetime is short.

On the other hand, anthraquinones generally have a dichroic ratio of 6~! The present inventors have developed a dye for display elements that utilizes the above-mentioned guest-host effect. Results of consideration.

The purpose of the present invention is to discover a dye with excellent dichroic ratio and light fastness and complete the present invention.The purpose of the present invention is to create a high-contrast, long-life guest using a dichroic dye with excellent both dichroic ratio and light fastness. An object of the present invention is to provide a wooden block type liquid crystal display element.

In a liquid crystal display element formed by filling a liquid crystal composition between a pair of electrode substrates, the liquid crystal composition may be represented by the following general formula: [wherein R is an alkyl group, an alkoxy group, or an aralkyl group; group, aryl group, aryloxy group, cyclohexyl group, R, alkyl group, aralkyl group, aryl group.

Represents a cyclohexyl group.

In the substituents of Ro and R1, the alkyl chain and the 7-aryl ring may be substituted.] A liquid crystal that uses a liquid crystal composition containing one type and two or more types of yellow pigments represented by the following. It is a display element.

The dye used in the present invention is generally synthesized as follows. That is, in the reaction formula shown below, the general formula (1
) is used in the general formula I), or when a halogenating agent is applied to the compound represented by the general formula (layer) to act on the compound represented by the general formula (layer), the compound represented by the general formula (I) is used. A yellow colorant of 30% is obtained.

V) [In the formula, R1, 11B have the above meanings @Y is a sulfuric acid ester residue or an arylsulfylic acid ester nine residue,
l represents a halogen atom. ] R of general formula (I) in ζ
Examples include methyl group, ethyl group, propylene group, butyl group, amyl group, straight or branched alkyl group such as methyl group, ethyl dipropyl group, ethoxypropyl group, propoxyethyl group, octoxyethyl group. , ethoxyethoxyalkylethyl group, straight chain or branched flukoxyalkyl group, methoxy, group, ethoxylethyl group.

Straight chain or branched alkoxy groups such as propoxy group, butoxy group, pentoxy group, hexyloxy group, octoxy group, nonyloxy group, p-butylbenzyl group, lp
-hexyl 7enethyl group, p-butoxybenzyl group, 7ralkyl group such as benzyl group, p-butylbenzylokyle group.

7-ralkyloxy groups such as p-butyloxybenzyloxy group and benzineoxy group, phenyl group, p-propylphenyl group, p-butyl 7! 70-l groups such as nyl group, p-hexylphenyl group, p-butokyrephenyl group, p-hexylokyrephenyl group, pheno! Representative substituents include a p-butylphenokyle group, a p-butylphenokyle group, a p-hexylphenoxy group, a p-hexyloxyhexyl group, and the like.

R1 is a straight-chain or branched alkyl group such as a propyl group, a butyl group, an amyl group, a hexyl group, an octyl group, a nonyl group, a dodecyl group, an ethoxypropyl group, a butoxyethyl group, a hexyelyl diethyl group, or an ethoxy group. Linear or branched fulco-cow sial with ethoxyethyl group 2
Kill group.

p-1 thylbenzyl group, p-hexylphenethyl group, p
-butoxybenzyl group, heptaralkyl group such as benzyl group, phenyl group, p-propylphenyl group Sp-butylphenyl group, p-hexylerphenyl group, p-octylphenyl group, p-butoxyphenyl group, p-hexyl Typical substituents include oxyphenyl group, p-butylbiphenyl group, p-butoxypiphenyl group, p-butylphenoxy7enyl group, cyclohexyl group, etc. 0 Typical examples include phosphorus trichloride, phosphorus pentachloride, phosphorus chloride, and phosphorus tribromide. 1 is a schematic cross-sectional view showing an example of a transmissive liquid crystal display device containing a liquid crystal display element of the present invention, and FIG. 1 is a schematic cross-sectional view of a reflective liquid crystal display element according to another embodiment of the present invention. In the figures, / is a transparent glass substrate, C is a transparent material such as indium oxide provided inside the transparent glass substrate, and J is a spacer made of, for example, a Teflon film, which allows the thickness of the cell to be is 7
It is adjusted to 0 to 20 μm. DA is a nematic liquid crystal composition containing a dichroic dye, j is a power supply applied to this element, and direct current or alternating current is used; 6 is incident light; Yes, L is a polarizing plate, and D is a plate for light scattering.In this device, the surface of the transparent electrode is rubbed against the meat with a cotton cloth cape, and the method is to obliquely evaporate bamboo, silicon oxide, etc. Nematic liquid crystals and dichroic dyes are transparent.The nematic liquid crystals exhibiting positive dielectric anisotropy used in the present invention have a general formula [where one of R and R4 is a reano group, the other is ◎ representing an alkyl group, a flukoxy group, an alkylphenyl group or an alkoxyphenyl group, or a mixture thereof can be opened. A reflective type display device as shown in the figure may also be used. In this case, a light scattering plate 9 is provided at the back of the panel.

Above, we have shown a display device whose color disappears when a voltage is applied, but conversely, a display device that becomes colored when a voltage is applied can be used as a component. A transparent electrode surface using a nematic liquid crystal exhibiting anisotropy is treated with a surfactant such as i, M-dimethyl-N-octadecyl-3-7minoprobyltrimethoxysilyl chloride, dimethyldichlorosilane, t, or methyltrichlorosilane. or by mixing an alignment agent such as cetyl methyl ammonium 70lide into the liquid crystal so that the liquid crystal and the dichroic dye are aligned on the transparent electrode surface KIIlfK to form a display device. In addition, when a small amount of cholesteric liquid crystal or chiral nematic liquid crystal is mixed with nematic liquid crystal, it becomes a display element due to the so-called phase transition W (or single Wight-Tiller type) guest-wood strike effect, and a polarizing plate. is not necessary and high contrast can be obtained even with reflective light.Next, we will show an example of synthesis of a typical surface dye used in the present invention. ” compound,
77 parts, 9 parts of thionyl chloride, 1 part of nitrobenzene, and 30 parts of nitrobenzene.
The mixture is heated to /3θ to /4tθ” OK in a section to form a compound represented by R1=OaH-, sn -X''-OZ in the general formula 0. Excess thionyl chloride was then expelled, cooled to -0 to 30°C, and p-n-amylphenol 3. -1 part and 2.74 parts of potassium carbonate, #j1
Stir overnight at 11 degrees. Next, 750 parts of methanol was added, and the precipitated crystals were separated, washed with methanol and then water, and dried. 3. O m-p-//7~//de C synthesis example (compound grave-) In the above general formula, R knee-04 part g H compound J, the two parts are sodium carbonate θ , s4 part and dichlorobenzene-0
The mixture was heated to 790 to 750°C for dehydration, and then 0 parts of p-1 luenesulfonic acid n-butyl ester was added and heated and stirred at /6θ to /7θ°C for about 6 hours. Cool to 70°C, add 100 parts of methanol, separate the nine crystals that precipitate, wash with methanol and then with water, and dry. The morning cake of kerosene was crystallized in chloroform-methanol to obtain 0 parts of a yellow pigment with the following structural formula. )※/
;Og! IyL9 is a trimer of propylene.

*λ; Oyo-86 is the 44'IIk isomer of propylene. Example: 41-cyanoda'-n-pentylbiphenyl 4tJ chidare 7no-10-n-propoxy was added to a liquid crystal cell treated so that the liquid crystal and dichroic dye were parallel to the transparent electrode. Biphenyl/7 vomit.

l-Sifno, /-n-pentoxybiphenyl/J%,
+-cyanoder p-octochylebiphenyl 17%, q
-Leanoda/-D-pentylterphenyl/θ-yu liquid crystal mixture (lt.

BDHOMmioaxs) with the above AI dye/
A composition of dissolved liquid crystal was added.

When a voltage of about 6 volts is applied to the liquid crystal display element, the yellow liquid crystal cell turns to colorless.

The wavelength of the AI dye in this liquid crystal display element is 6 nm.
Therefore, the light resistance of the single liquid crystal display element was very good.

Example - Liquid crystal cell subjected to direct alignment or parallel alignment treatment) 0 - A mixed liquid crystal obtained by adding a nematic liquid crystal with positive Ill power orientation zgK cholesteric liquid crystal material cholesteryl chloride/θ% (weight ratio) to the above A- In the configuration shown in Figure 1, in which a liquid crystal composition in which /% of dye is dissolved is injected.
This liquid crystal display element is colored yellow when no voltage is applied, and /!
When a voltage higher than V power was applied, it became colorless, and a bright, high-entrast reflective display was obtained without using a polarizing plate.The cholesteric liquid crystal material used for the 6-layer liquid crystal is the above-mentioned cholesteryl chloride. In addition, among cholesteryl derivatives, chiral nematic materials such as biphenyl or ester can also be used.

[Brief explanation of drawings]

FIG. 7 is a schematic cross-sectional view of a transmission type liquid crystal display device using a liquid crystal display element according to an embodiment of the present invention. FIG. 1 is a schematic cross-sectional view of a reflective liquid crystal display device according to another embodiment of the present invention. - In the figure, incident light, 7... eye viewer, l... polarizing plate, ri... light scattering plate@

Claims (1)

[Scope of Claims] A liquid crystal display element in which a liquid crystal composition is emitted between a pair of electrode substrates, at least one of which is transparent, wherein the liquid crystal composition is represented by the following general formula (1). A liquid crystal display element O whose 4I image is the use of a liquid crystal composition containing one or more kinds of yellow pigments [wherein, R is excluded from an alkyl group, an alkoxy group, an aralkyl group, an aralkyloxy group, an aryl group] group, aryloxy group, cyclohexyl group. R represents an alkyl group, an aralkyl group, an aryl group, or a cyclohexyl group. R, in the substituents of Ra, the alkyl chain and aryl ring may be substituted O]