JP2717446B2 - Liquid crystal composition and liquid crystal display device using the same - Google Patents

Description

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

(Prior Art) A display element utilizing a guest-host effect in which a dichroic dye is added to liquid crystal has the following advantages. (2) Various display colors can be easily realized by selecting a dye. (3) Since it does not necessarily require a polarizing plate, it has features such as being capable of bright display, and is attracting attention as a display element particularly suitable for medium to large displays.

However, a conventionally known display device using a guest-host effect by adding a dichroic dye to liquid crystal has difficulty in simultaneously satisfying all of high contrast, long life and various hues. The reason for this is that, besides the fact that there are few dichroic dyes that are excellent in both dichroism and light resistance, when different types of dyes are blended, light deterioration of any dye, Often accelerated, the lightfastness is lower than when the dyes are used alone. The resulting deterioration due to light is observed as discoloration or fading, and is measured as an increase in power consumption.

For this reason, it is conventionally difficult to achieve both high contrast and long life for various hues which require the addition of dichroic dyes such as green and yellow green such as yellow and blue. Was.

(Problems to be Solved by the Invention) The present invention solves the above-mentioned problems of the prior art, has excellent light fastness, and has a liquid crystal composition having excellent contrast and lifetime, and a liquid crystal composition using the same. The purpose is to obtain a liquid crystal display element.

(Means for Solving the Problems) As a result of repeated studies to achieve the above object, the present inventors have found that a liquid crystal composition containing at least two types of dichroic dyes having a specific structure, and a liquid crystal composition using the same. The present inventors have found that the conventional liquid crystal display element is suitable for this purpose and achieved the present invention. That is, the gist of the present invention is to provide a liquid crystal material comprising a compound represented by the general formula [I]: Wherein R ¹ is a hydrogen atom, a halogen atom, an alkyl group, an alkoxyalkyl group, an alkoxy group, an alkylphenyl group, an alkoxyphenyl group or a formula (Wherein, R ³ represents a hydrogen atom, an alkyl group, an alkoxyalkyl group or an alkoxy group, and Y is Represents a substituent represented by, R ² represents a hydrogen atom, a halogen atom, an alkyl group, an alkoxyalkyl group or an alkoxy group, X ¹ is a halogen atom as a substituent at the o-position or m-position, an alkyl group, an alkoxy The phenylene group which may have a group is shown. And at least one selected from quinophthalone dichroic dyes represented by the following general formula [II]: (Wherein, R ⁴ represents a hydrogen atom, an alkyl group, an alkoxyalkyl group, an alkoxy group, or an alkyl group, a cyclohexyl group optionally substituted with an alkoxyalkyl or an alkoxy group, and R ⁵ represents a hydrogen atom, an alkyl group, An alkoxyalkyl group, or an alkyl group, a cyclohexyl group optionally substituted with an alkoxyalkyl group or an alkoxy group, or an alkyl group, an alkoxyalkyl group, a phenyl group optionally substituted with an alkoxy group or a halogen atom. , Represents a trans 4-substituted cyclohexyl group. A liquid crystal composition comprising at least one selected from an anthraquinone dichroic dye represented by the formula (1), and at least one of the liquid crystal compositions supported between transparent electrode substrates. It exists in liquid crystal display devices.

 Hereinafter, the present invention will be described in detail.

The liquid crystal composition of the present invention is characterized by containing a quinophthalone dichroic dye represented by the general formula [I] and an anthraquinone dichroic dye represented by the general formula [II]. It is.

In the quinophthalone dichroic dye represented by the formula [I], R ¹ is a hydrogen atom; a halogen atom such as a fluorine atom, a chlorine atom, and a bromine atom; a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group , Hexyl group, octyl group,
Linear or branched alkyl groups such as nonyl group and dodecyl group; linear or branched alkoxyalkyl groups such as methoxymethyl group, butoxymethyl group, methoxypropyl group, ethoxyethyl group and butoxyethyl group A methoxy group,
Straight-chain or branched alkoxy groups such as ethoxy, propoxy, butoxy, pentoxy, and octoxy groups; straight-chain groups such as ethylphenyl, propylphenyl, butylphenyl, hexylphenyl, and nonylphenyl Linear or branched alkylphenyl group; linear or branched alkoxyphenyl group such as methoxyphenyl group, ethoxyphenyl group, butoxyphenyl group, pentoxyphenyl group or the like; Wherein R ³ in this formula is
Hydrogen atom; methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, octyl group, nonyl group,
A linear or branched alkyl group such as a dodecyl group; a methoxymethyl group, a butoxymethyl group, a methoxypropyl group,
Linear or branched alkoxyalkyl groups such as ethoxyethyl group and butoxyethyl group; linear or branched alkoxy groups such as methoxy group, ethoxy group, propoxy group, butoxy group, pentoxy group and octoxy group Is mentioned.

R ^{2 in the} formula [I] represents 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 Straight-chain or branched alkoxyalkyl groups such as butoxyethyl group, etc .; straight-chain or branched alkoxy groups such as methoxy group, ethoxy group, propoxy group, butoxy group, pentoxy group and octoxy group. Can be

In addition, o of the phenylene group of X ¹ in the general formula [I]
The halogen atom which may be present at the-or m-position includes a fluorine atom, a chlorine atom, a bromine atom and the like, and the alkyl group includes a methyl group, an ethyl group, a propyl group, a butyl group and a pentyl group. A linear or branched alkyl group,
Further, examples of the alkoxy group include linear or branched alkoxy groups such as a methoxy group, an ethoxy group, a propoxy group, a butoxy group, and a pentoxy group.

Next, in the anthraquinone dichroic dye represented by the aforementioned general formula [II], R ⁴ is a hydrogen atom; a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, an octyl group, Nonyl group, linear or branched alkyl group such as dodecyl group; methoxymethyl group, butoxymethyl group, methoxypropyl group, ethoxyethyl group,
Linear or branched alkoxyalkyl groups such as butoxyethyl group; cyclohexyl group; propylcyclohexyl group, butylcyclohexyl group, pentylcyclohexyl group, hexylcyclohexyl group, octylcyclohexyl group, methoxymethylcyclohexyl group, butoxyethylcyclohexyl group, A cyclohexyl group which may have a linear or branched alkyl group, an alkoxyalkyl group or an alkoxy group as a substituent, such as a pentoxybutylcyclohexyl group, a methoxycyclohexyl group, a propoxycyclohexyl group, an octoxycyclohexyl group; Examples thereof include linear or branched alkoxy groups such as a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a pentoxy group, and an octoxy group. R ^{5 in the} formula [III] is a hydrogen atom; methyl, ethyl, propyl, butyl, pentyl, hexyl, octyl,
Linear or branched alkyl groups such as nonyl group and dodecyl group; linear or branched alkoxyalkyl groups such as methoxymethyl group, butoxymethyl group, methoxypropyl group, ethoxyethyl group and butoxyethyl group A cyclohexyl group; a propylcyclohexyl group, a butylcyclohexyl group, a pentylcyclohexyl group, a hexylcyclohexyl group, an octylcyclohexyl group, a methoxymethylcyclohexyl group, a butoxyethylcyclohexyl group, a pentoxybutylcyclohexyl group, a methoxycyclohexyl group, a propoxycyclohexyl group, and octoxy group. A cycloalkyl group which may have a linear or branched alkyl group, alkoxyalkyl group or alkoxy group such as cyclohexyl group as a substituent; phenyl group, ethylphenyl group, Butylphenyl group, butylphenyl group,
Hexylphenyl, octylphenyl, nonylphenyl, methoxyphenyl, ethoxyphenyl, butoxyphenyl, pentoxyphenyl, octoxyphenyl, methoxymethylphenyl, butoxyphenylethylphenyl, fluorophenyl, chlorophenyl And a phenyl group which may be substituted with an alkyl group, an alkoxyalkyl group or an alkoxy group such as a bromophenyl group.

On the other hand, as the liquid crystal substance used in the present invention, for example, simple substances of various compounds known as liquid crystal substances represented by the following general formulas or mixtures thereof are used.

(In the above general formula, R ⁶ and R ⁷ 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 , Cyanophenyl group, cyano group, halogen atom, alkoxycarbonyl group, alkoxyalkoxycarbonyl group, alkylphenoxycarbonyl group, alkoxyalkylphenoxycarbonyl group, alkoxyphenoxycarbonyl group, alkylcyclohexyloxycarbonyl group, alkylcyclohexylphenoxycarbonyl group,
A cyanophenoxycarbonyl group, a halogenophenoxycarbonyl group, an alkylphenylalkyl group, an alkoxyalkylphenylalkyl group, an alkoxyphenylalkyl group, an alkylcyclohexylalkyl group, an alkoxyalkoxycyclohexylalkyl group, an alkylcyclohexylphenylalkyl group, and a cyanophenylalkyl group. The alkyl chain or the alkoxy chain may have an optically active center. Further, the phenyl group or phenoxy group in R ⁶ and R ⁷ may be substituted with a halogen atom such as a fluorine atom and a chlorine atom. X ² represents a hydrogen atom or a halogen atom such as a fluorine atom and a chlorine atom. Note that these liquid crystal substances may contain additives such as an optically active substance such as cholesteryl nonanoate, an ultraviolet absorber, and an antioxidant.

The liquid crystal composition of the present invention comprises, in the above-mentioned liquid crystal substance, at least one quinophthalone-based dichroic dye represented by the formula [I] and at least one anthraquinone-based dichroic dye represented by the formula [II]. Can be easily prepared by dissolving

The liquid crystal composition prepared in this manner is supported between at least one of the transparent electrode substrates, thereby applying a guest-host effect to the display element “Shoichi Matsumoto and Ryo Tsunoda,“ Latest Technologies for Liquid Crystals ”34 Page (1983), published by the Industrial Research Council "and" JLFergason, SID 85 Digest 68 (1985) "
Can be configured.

(Examples) Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples unless it exceeds the gist.

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

S = (AA −) / (A + 2A⊥) Here, A and A⊥ are the absorbances of the dye for light polarized parallel and perpendicular to the alignment direction of the liquid crystal, respectively.

The order parameter (S) is, specifically, a value indicating the display contrast of the guest-host type liquid crystal display element. As this value approaches 1 theoretically, the residual color degree of the white portion decreases and the brightness increases. A clear display with a large contrast becomes possible. The general formula [I] used in the following examples
Table 1-1 and Table 1-2 show the quinophthalone dichroic dyes
And an anthraquinone dichroic dye represented by the general formula [II] are shown in Table 2-1.

Example 1 The following dichroic dye was dissolved in 100 g of a liquid crystal mixture containing a phenylcyclohexane-based compound as a main component, which is commercially available as ZLI-1565 (trade name, manufactured by E. MERCK), to give a liquid crystal composition-I. Prepared.

Colorant [I-1] 1.35 g [II-9] 0.96 g [I-1] 1.55 g On the other hand, a glass plate with a transparent electrode that has been applied with a polyimide resin, cured, rubbed, and subjected to a homogeneous alignment treatment. The liquid crystal composition I obtained above was placed in a 9 μm gap cell configured so that the alignment treatment surfaces faced each other.
Was enclosed to prepare a liquid crystal display device.

As a result of calculating the order parameter (S) of this liquid crystal display element, at 639 nm and 459 nm, 0.74 and
It was 0.73. The cell in which the liquid crystal composition-I was sealed was subjected to a light fastness test using a fade meter (carbon arc light source). As a result, a hue change after 200 hours: ΔE ^* (L ^* a)
^* B ^* method) is 3.3 or less, the current value increase rate I / Io (applied voltage: 5 V, 32 Hz) is 3.0, and each absorption peak (639
nm and 459 nm) was 3.0% or less.

Example 2 A liquid crystal composition-II was prepared by dissolving the following dichroic dye in 100 g of the liquid crystal mixture containing a phenylcyclohexane-based compound as a main component used in Example 1.

Color element [I-2] 0.55 g [II-3] 1.05 g [I-3] 0.63 g [II-10] 0.56 g [I-4] 0.49 g [II-11] 0.24 g [II-2] 1.15 g [II-12] 0.66 g This liquid crystal composition-II was sealed in a 9 μm gap cell made of the same glass plate with a transparent electrode as in Example 1 and arranged so that the alignment treatment surfaces faced each other. A liquid crystal display device was created.

As a result of calculating the order parameter (S) of this liquid crystal display element, 0.74 and 634 nm and 460 nm, respectively, were obtained.
It was 0.73. The cell in which the liquid crystal composition-II was sealed was subjected to a light fastness test using a fade meter (carbon arc light source). As a result, the hue change after 200 hours: ΔE ^* (L ^* a)
^* B ^* method) is 3.2 or less, the current value increase rate I / Io (applied voltage: 5 V, 32 Hz) is 2.7, and each absorption peak (634)
nm and 460 nm) was less than 3.3%.

Example 3 A liquid crystal composition-III was prepared by dissolving the following dichroic dye in 100 g of a liquid crystal mixture containing a phenylcyclohexane-based compound as a main component used in Example 1.

Color element [I-5] 0.48 g [II-5] 1.22 g [I-6] 0.39 g [II-6] 1.31 g [I-7] 0.62 g [II-9] 1.62 g [II-4] 1.13 g [II-10] 1.48 g This liquid crystal composition-III was sealed in a gap 9 μm cell made of the same glass plate with a transparent electrode as in Example 1 and arranged so that the alignment treatment surfaces faced each other. A liquid crystal display device was created.

As a result of calculating the order parameter (S) of the liquid crystal display element, the order parameter (S) at 639 nm and 462 nm was 0.73 and 462 nm, respectively.
It was 0.72. The cell in which the liquid crystal composition-III was sealed was subjected to a light fastness test using a fade meter (carbon arc light source). As a result, the hue change after 200 hours: ΔE ^* (L ^*
a ^* b ^* method) is 3.0 or less, and the current value increase rate I / Io
(Applied voltage: 5 V, 32 Hz) was 3.3, and the absorbance change at each absorption peak (639 nm and 462 nm) was 3.2% or less.

Example 4 The following dichroic dye was dissolved in 100 g of a liquid crystal mixture containing a phenylcyclohexane-based compound as a main component and commercially available as ZLI-1840 (trade name of E. MERCK) to obtain a liquid crystal composition-IV. Prepared.

Colorant [I-2] 1.10 g [II-7] 1.22 g [I-8] 0.54 g [II-8] 1.19 g [I-9] 0.41 g This liquid crystal composition-IV was the same as in Example 1. A liquid crystal display device was prepared by enclosing in a cell having a gap of 9 μm, which was made of a glass plate with a transparent electrode, and whose orientation-treated surfaces were opposed to each other.

As a result of calculating the order parameter (S) of this liquid crystal display element, at 634 nm, 596 nm and 463 nm, respectively.
0.74, 0.73 and 0.72. The cell in which the liquid crystal composition-IV was sealed was subjected to a light fastness test using a fade meter (carbon arc light source). As a result, a change in hue after 200 hours:
ΔE ^* (L ^* a ^* b ^* method) is 3.4 or less, the current value increase rate I / Io (applied voltage: 5 V, 32 Hz) is 3.3, and each absorption peak (634 nm, 596 nm and 463 nm) Absorbance change is
It was 3.5% or less.

Example 5 The following dichroic dye was dissolved in 100 g of a liquid crystal mixture containing a phenylcyclohexane-based compound as a main component used in Example 4, to prepare a liquid crystal composition-V.

Colorant [I-8] 1.11 g [II-14] 0.70 g [I-10] 0.34 g [II-15] 0.72 g [II-13] 0.84 g This liquid crystal composition-V was the same as in Example 1. A liquid crystal display device was prepared by enclosing in a cell having a gap of 9 μm, which was made of a glass plate with a transparent electrode, and whose orientation-treated surfaces were opposed to each other.

As a result of calculating the order parameter (S) of the liquid crystal display element, the order parameter (S) at 665 nm and 462 nm was 0.74 and 462 nm, respectively.
It was 0.72. The cell in which the liquid crystal composition-V was sealed was subjected to a light fastness test using a fade meter (carbon arc light source). As a result, a hue change after 200 hours: ΔE ^* (L ^* a)
^* B ^* method) is 3.3 or less, the current value increase rate I / Io (applied voltage: 5 V, 32 Hz) is 3.6, and each absorption peak (665
nm and 462 nm) was 4% or less.

In addition to the dyes used in the above Examples, Table 1 shown below
-3, Tables 1-4 and 2-2 are used as the liquid crystal composition and the liquid crystal device of the present invention.

(Effect of the Invention) The color liquid crystal composition containing a combination of the dichroic dyes having a specific structure and the liquid crystal display device using the same according to the present invention utilize the guest-host effect of the dichroic dyes and have light resistance. In particular, for various hues such as green and yellow green which require the blending of yellow and blue dichroic dyes, they have the effect of simultaneously satisfying high contrast and long life which have been considered difficult. And its practical value is great.

Claims (2)

(57) [Claims] A liquid crystal material and a compound represented by the general formula [I]: Wherein R ¹ is a hydrogen atom, a halogen atom, an alkyl group, an alkoxyalkyl group, an alkoxy group, an alkylphenyl group, an alkoxyphenyl group or a formula (Wherein, R ³ represents a hydrogen atom, an alkyl group, an alkoxyalkyl group or an alkoxy group, and Y is Represents a substituent represented by, R ² represents a hydrogen atom, a halogen atom, an alkyl group, an alkoxyalkyl group or an alkoxy group, X ¹ is a halogen atom as a substituent at the o-position or m-position, an alkyl group, an alkoxy The phenylene group which may have a group is shown. And at least one selected from quinophthalone dichroic dyes represented by the following general formula [II]: (Wherein, R ⁴ represents a hydrogen atom, an alkyl group, an alkoxyalkyl group, an alkoxy group, or an alkyl group, a cyclohexyl group optionally substituted with an alkoxyalkyl or an alkoxy group, and R ⁵ represents a hydrogen atom, an alkyl group, An alkoxyalkyl group, or an alkyl group, a cyclohexyl group optionally substituted with an alkoxyalkyl group or an alkoxy group, or an alkyl group, an alkoxyalkyl group, a phenyl group optionally substituted with an alkoxy group or a halogen atom, Represents a trans 4-substituted cyclohexyl group. A liquid crystal composition comprising at least one selected from anthraquinone-based dichroic dyes represented by the following formula: 2. A liquid crystal display device comprising at least one transparent electrode substrate carrying a liquid crystal composition between transparent electrode substrates, wherein the liquid crystal composition according to claim 1 is used as the liquid crystal composition. Display element.