JPH0759706B2 - Liquid crystal composition and display device using the composition - Google Patents

Description

TECHNICAL FIELD The present invention relates to a liquid crystal composition and a display device using the same,
In particular, the present invention relates to a color liquid crystal composition having excellent light resistance and a display device.

(Prior Art) A display element utilizing the guest-host effect in which a dichroic dye is added to liquid crystal has a wide viewing angle of 1). 2) Various display colors can be easily realized by selecting the dye. 3) Since it does not necessarily require a polarizing plate, it has a feature that bright display is possible. Therefore, it is attracting attention as a display element particularly suitable for medium to large-sized display.

(Problems to be Solved by the Invention) However, conventionally, it has been difficult for a display device utilizing a guest-host effect in which a dichroic dye is added to liquid crystal to simultaneously satisfy high contrast, long life and various hues. This is due to the fact that there are few dichroic dyes that have both excellent dichroism and light resistance, and when different types of dyes are blended, photodegradation of one of the dyes, especially photodegradation due to ultraviolet rays, is often accelerated. Therefore, the light resistance is lower than that when the dye is used alone. The deterioration due to the light thus generated is observed as discoloration or fading, and there is a problem in that it is measured as an increase in current consumption. Therefore, conventionally, for a variety of hues for which it is necessary to mix yellow-based, red-based, and blue-based dichroic dyes such as black, brown, and dark blue,
In particular, there is a problem that it is difficult to achieve both contrast and long life. An object of the present invention is to provide a color liquid crystal composition and a display device capable of solving the above conventional problems.

(Means for Solving the Problems) The present invention relates to a liquid crystal composition having excellent contrast and life. That is, the present invention relates to a liquid crystal substance and the following general formula [I] (In the formula, R ^{1 to} R ³ represent a hydrogen atom, a halogen atom, an alkyl group, an alkoxyalkyl group, an alkoxy group or a cyclohexyl group which may have an alkyl group, and A represents Indicates. ) At least one of the anthraquinone-based dichroic dyes represented by the general formula [II] (In the formula, R ⁴ represents a hydrogen atom, a halogen atom, an alkyl group, an alkoxyalkyl group, an alkoxy group or a cyclohexyl group which may have an alkyl group, and X ¹ has a hydrogen atom, a halogen atom or a substituent. An anthraquinone-based dichroic dye represented by the formula (III) (In the formula, R ⁵ and R ⁶ represent a hydrogen atom, a halogen atom, an alkyl group, an alkoxyalkyl group, an alkoxy group or a cyclohexyl group which may have an alkyl group.) Anthraquinone-based dichroic dye From at least one and the general formula [IV] (In the formula, R ⁷ represents a hydrogen atom, a halogen atom, an alkyl group, an alkoxyalkyl group, an alkoxy group or a cyclohexyl group which may have an alkyl group, and R ⁸ represents a hydrogen atom, a halogen atom, an alkyl group, an alkoxyalkyl group. Group, an alkoxy group, a cyclohexyl group which may have an alkyl group, or a phenyl group which may be substituted with an alkyl group or an alkoxy group)). And a display element having at least one of the liquid crystal compositions carried between transparent electrode substrates.

To explain the present invention in more detail, the general formula [I]
R ^{1 to} R ⁷ in [IV] are a hydrogen atom; a halogen atom such as a fluorine atom, a chlorine atom and a bromine atom; a methyl group;
Linear or branched alkyl groups such as ethyl group, propyl group, butyl group, pentyl group, hexyl group, octyl group, nonyl group, dodecyl group; methoxymethyl group, butoxymethyl group, methoxypropyl group, ethoxyethyl Group, linear or branched alkoxyalkyl group such as butoxyethyl group; linear or branched alkoxy group such as methoxy group, ethoxy group, propoxy group, butoxy group, pentoxy group, octoxy group; cyclohexyl Group, a propylcyclohexyl group, a butylcyclohexyl group, a pentylcyclohexyl group, a hexylcyclohexyl group, a cyclohexyl group which may have a linear or branched alkyl group such as an octylcyclohexyl group. the X ¹ in II], hydrogen atom; a fluorine atom, a chlorine atom, a bromine atom, etc. Halogen atom; a methoxycarbonyl group, an ethoxycarbonyl group, butoxycarbonyl group,
Alkoxycarbonyl group such as octylcarbonyl group, butylphenoxycarbonyl group, octylphenoxycarbonyl group, alkyl group such as butoxyphenoxycarbonyl group, phenoxycarbonyl group optionally substituted with alkoxy group, trans-4-butylcyclohexyloxycarbonyl Group, a linear or branched alkyl group such as trans-4-octylcyclohexyloxycarbonyl group, a carboxylic group which may have a substituent such as a cyclohexyloxycarbonyl group which may be substituted with an alkoxy group and the like. Acid ester group, the general formula [I
V], R ⁸ is hydrogen atom; halogen atom such as fluorine atom, chlorine atom, bromine atom, methyl group, ethyl group,
A linear or branched alkyl group such as propyl group, butyl group, pentyl group, hexyl group, octyl group, nonyl group, dodecyl group; methoxymethyl group, butoxymethyl group,
Linear or branched alkoxyalkyl groups such as methoxypropyl group, ethoxyethyl group, butoxyethyl group; linear or branched groups such as methoxy group, ethoxy group, propoxy group, butoxy group, pentoxy group, octoxy group, etc. -Like alkoxy group; cyclohexyl group, propylcyclohexyl group, butylcyclohexyl group, pentylcyclohexyl group, hexylcyclohexyl group, cyclohexyl group which may have a linear or branched alkyl group such as octylcyclohexyl group; phenyl group , A phenyl group which may be substituted with an alkyl group or an alkoxy group such as an ethylphenyl group, a butylphenyl group, an octylphenyl group, a butoxyphenyl group and an octyloxyphenyl group.

In each of the dyes represented by the general formulas [I] to [IV], when a substituted cyclohexyl group is contained in the structure, trans-4-
It is preferably a substituted cyclohexyl group.

The liquid crystal substance used in the present invention has the following general formula (In the formula, R ⁹ and R ¹⁰ are an alkyl group, an alkoxyalkyl group, an alkoxy group, an alkylphenyl group, an alkoxyalkylphenyl group, an alkoxyphenyl group, an alkylcyclohexyl group, an alkoxyalkylcyclohexyl group, an alkylcyclohexylphenyl group, and a cyanophenyl group. , Cyano group, halogen atom, alkoxycarbonyl group, alkoxyalkoxycarbonyl group, alkylphenoxycarbonyl group, alkoxyalkylphenoxycarbonyl group, alkoxyphenoxycarbonyl group, alkylcyclohexyloxycarbonyl group, alkoxycyclohexyloxycarbonyl group, alkylcyclohexylphenoxycarbonyl group, Cyanophenoxycarbonyl group, halogenphenoxycarbonyl group, alkylphenylalkyl group, Coxyalkylphenylalkyl group, alkoxyphenylalkyl group, alkylcyclohexylalkyl group, alkoxyalkoxycyclohexylalkyl group, alkylcyclohexylphenylalkyl group, cyanophenylalkyl group, having an optically active center in the alkyl chain or alkoxy chain Is also good.
Further, the phenyl group or phenoxy group in R ⁹ and R ¹⁰ may be substituted with a halogen atom such as a fluorine atom or a chlorine atom. X ² represents a hydrogen atom or a halogen atom such as a fluorine atom and a chlorine atom. And liquid crystal substances such as a single substance of the compound represented by the formula) or a mixture thereof.

In addition, the above liquid crystal composition may contain an additive such as an optically active substance such as cholesteryl nonanoate, an ultraviolet absorber and an antioxidant.

The liquid crystal composition of the present invention can be easily prepared by dissolving the dye represented by the structural formulas [I] to [IV] in the liquid crystal substance.

The liquid crystal composition thus prepared is supported between at least one of the transparent electrode substrates so that a display device applying the guest-host effect [Shouichi Matsumoto, Ichino Tsunoda,
"Latest LCD Technology" Industrial Research Group 34 (1983) JLFergaso
n, SID 85 Digest 68 (1985), etc.] can be configured.

〔Example〕

Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited to the following Examples as long as the gist thereof is not exceeded.

In the following examples, the quality of dichroism is determined by the order parameter (S) of the dye compound obtained from the following equation.
It was evaluated by.

Here, A and A⊥ are the absorbances of the dye with respect to light polarized parallel and perpendicular to the alignment direction of the liquid crystal, respectively.

The order parameter (S) is
It is a value indicating the display contrast of the host-type liquid crystal display element. As this value theoretically approaches 1, the residual color level of the non-white areas is reduced, and a bright and clear display with a large contrast becomes possible.

In addition, the dyes used in the following examples are collectively shown in Table 1.

Incidentally, 4-substituted cyclohexyl groups are all trans-4
-Represents a substituted cyclohexyl group.

Example 1 A liquid crystal composition prepared by dissolving the following dichroic dye in 100 g of a liquid crystal mixture containing a phenylcyclohexane compound commercially available under the trade name ZLI-1565 (manufactured by E.MERCK) as a main component.
I was adjusted.

Dye [I-1] 2.80 g [II-1] 2.00 g [III-1] 0.87 g [IV-1] 0.40 g [IV-9] 0.80 g This is coated with a polyimide resin and cured, and then rubbed to homogeneity. A liquid crystal display device was prepared by enclosing in a cell having a gap of 9 μm, which is composed of a glass plate with a transparent electrode that has been subjected to an alignment treatment and is configured so that the alignment treated surfaces face each other.

As a result of calculating the order parameter (S) of this liquid crystal display device, it was 0.74, 0.72 and 0.70 at 575 nm, 539 nm and 467 nm, respectively. A cell in which the liquid crystal composition-I is enclosed is a fade meter (carbon arc light source).
As a result of the light resistance test carried out at, the hue change after 200 hours: ΔE ^* (L ^* a ^* b ^* method) is 3 or less, and the rate of increase of the current value I / I ₀ (applied voltage: 5V, 32Hz ) Is 2.5, and the change in absorbance at each absorption peak (575 nm, 539 nm, 467 nm) is 3
% Or less.

Example 2 A liquid crystal composition-II was prepared in the same manner as in Example 1 except that the following dichroic dye was used as the dye.

Dye [I-2] 2.20 g [I-3] 2.10 g [II-2] 1.55 g [II-3] 1.35 g [III-3] 1.33 g [IV-2] 0.20 g [IV-3] 0.30 g [IV-4] 0.30 g [IV-9] 1.05 g [IV-10] 0.55 g A liquid crystal display device was prepared in the same manner as in Example 1, and the order parameter (S) of this liquid crystal display device was prepared.
Was calculated to be 0.74, 0.72 and 0.70 at 573 nm, 536 nm and 465 nm, respectively. As a result of carrying out a light resistance test with a fade meter (carbon arc light source) on the cell in which the liquid crystal composition-II was enclosed, the hue change after 200 hours: ΔE ^* (L ^* a ^* b ^* method) was 3.2 or less. Yes,
The rate of increase in current value I / I ₀ (applied voltage: 5 V, 32 Hz) was 2.4, and the change in absorbance at each absorption peak (573 nm, 536 nm, and 465 nm) was 3% or less.

Example 3 A liquid crystal composition-III was prepared in the same manner as in Example 1 except that the following dichroic dye was used as the dye.

Dye [I-4] 1.40 g [I-5] 1.45 g [I-6] 1.60 g [II-4] 1.36 g [II-6] 1.45 g [III-2] 1.45 g [III-4] 1.60 g [IV-5] 1.57 g [IV-6] 1.62 g A liquid crystal display device was prepared in the same manner as in Example 1, and the order parameter (S) of this liquid crystal display device was prepared.
As a result of the calculation, at 580 nm and 470 nm, it was 0.
73 and 0.69. The cell in which the liquid crystal composition-III was enclosed was subjected to a light resistance test with a fade meter (carbon arc light source), and as a result, a hue change after 200 hours: ΔE
^* (L ^* a ^* b ^* method) is 3.7 or less, current rate of increase I / I ₀ (applied voltage: 5V, 32Hz) is 3.3, and absorbance change at each absorption peak (580nm and 470nm) Was 4% or less.

Example 4 A liquid crystal composition prepared by dissolving the following dichroic dye in 100 g of a liquid crystal mixture containing a phenylcyclohexane compound as a main component, which is commercially available under the trade name ZLI-1840 (manufactured by E.MERCK).
The IV was adjusted.

Dye [I-7] 2.10 g [I-8] 2.30 g [II-1] 1.00 g [II-5] 1.20 g [III-2] 1.00 g [IV-7] 1.00 g [IV-8] 0.50 g [IV-11] 0.50g [IV-12] 0.50g [IV-13] 0.50g This was enclosed in a cell in the same manner as in Example 1 to prepare a liquid crystal display element.

As a result of calculating the order parameter (S) of this liquid crystal display element, at 630 nm, 579 nm, 541 nm and 467 nm,
The values were 0.74, 0.73, 0.73 and 0.69, respectively. As a result of carrying out a light resistance test with a fade meter (carbon arc light source) on the cell in which the liquid crystal composition-IV was enclosed, the hue change after 200 hours: ΔE ^* (L ^* a ^* b ^* method) was 3.7 or less. Yes, the current rate of increase I / I ₀ (applied voltage: 5V, 32Hz)
2.9, and each absorption peak (630 nm, 579 nm, 541 nm and
The change in absorbance at 467 nm) was less than 3%.

Example 5 Liquid Crystal Composition-V was prepared in the same manner as in Example 4 except that the following dichroic dye was used as the dye.

Dye [I-9] 2.50 g [II-2] 0.40 g [II-3] 0.35 g [II-7] 0.42 g [III-5] 0.66 g [III-6] 0.75 g [IV-10] 0.60 g [IV-14] 0.70 g [IV-15] 0.72 g Using this, a liquid crystal display element was prepared in the same manner as in Example 1.

As a result of calculating the order parameter (S) of this liquid crystal display device, it was 0.74, 0.73 and 0.68 at 664 nm, 580 nm and 467 nm, respectively. A cell in which the liquid crystal composition-V is enclosed is a fade meter (carbon arc light source).
As a result of conducting a light resistance test at 200, the hue change after 200 hours: ΔE ^* (L ^* a ^* b ^* method) is 3.5 or less, and the rate of increase in current value I / I ₀ (applied voltage: 5V, 32Hz ) Was 3.8, and the change in absorbance at each absorption peak (664 nm, 580 nm, 467 nm) was 4% or less.

(Effects of the Invention) As is clear from the above results, the color liquid crystal composition containing the combination of the specific dichroic dyes of the present invention and the liquid crystal display device using the liquid crystal composition are added with the dichroic dyes. A variety of hues such as black, brown, dark blue, etc. that utilize the guest-host effect and have excellent light resistance, and sometimes require the addition of dichroic dyes of yellow, red and blue Has the industrially valuable and remarkable effect of making it possible to achieve both the contrast and the long life that were considered difficult.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display area C09B 1/60 C09K 19/60 F 9279-4H E 9279-4H C 9279-4H // G02F 1 / 13 500

Claims (2)

[Claims] 1. A liquid crystal substance and the following general formula [I]: (In the formula, R ^{1 to} R ³ represent a hydrogen atom, a halogen atom, an alkyl group, an alkoxyalkyl group, an alkoxy group or a cyclohexyl group which may have an alkyl group, and A represents Indicates. ) At least one of the anthraquinone-based dichroic dyes represented by the general formula [II] (In the formula, R ⁴ represents a hydrogen atom, a halogen atom, an alkyl group, an alkoxyalkyl group, an alkoxy group or a cyclohexyl group which may have an alkyl group, and X ¹ represents a hydrogen atom, a halogen atom, or a substituent. A dicarboxylic acid ester group which may be used), at least one of the anthraquinone dichroic dyes represented by the general formula [III] (In the formula, R ⁵ and R ⁶ represent a hydrogen atom, a halogen atom, an alkyl group, an alkoxyalkyl group, an alkoxy group or a cyclohexyl group which may have an alkyl group.) Anthraquinone-based dichroic dye From at least one and the general formula [IV] (In the formula, R ⁷ represents a hydrogen atom, a halogen atom, an alkyl group, an alkoxyalkyl group, an alkoxy group or a cyclohexyl group which may have an alkyl group, and R ⁸ represents a hydrogen atom, a halogen atom, an alkyl group, an alkoxyalkyl group. Group, an alkoxy group, a cyclohexyl group which may have an alkyl group, or a phenyl group which may be substituted with an alkyl group or an alkoxy group)). A liquid crystal composition comprising: 2. A liquid crystal display device having a liquid crystal composition supported between at least one transparent electrode substrate, wherein the liquid crystal composition according to claim 1 is used as the liquid crystal composition. .