JPH0745662B2 - Liquid crystal composition and display device using the composition - Google Patents

Description

TECHNICAL FIELD The present invention relates to a color liquid crystal composition having excellent contrast, light resistance and stability at low temperatures, and a display device.

(Prior Art) A display device utilizing a guest-host effect in which a dichroic dye is added to liquid crystal has a wide viewing angle, 2) a variety of display colors can be easily realized by selecting a dye, and 3) a polarizing plate. Since it does not always need to have a bright display, it has characteristics such as a bright display, and thus has attracted attention as a display element particularly suitable for medium to large display.

However, conventionally, it has been difficult for a display device utilizing the guest-host effect in which a dichroic dye is added to liquid crystal to simultaneously satisfy high contrast, long life, stability at low temperature and various hues. One of the reasons for this is that, in addition to the small number of dichroic dyes that are excellent in dichroism, light resistance and solubility, when different dyes are mixed, photodegradation of either dye, Deterioration is often accelerated and the light resistance is lower than that when the dyes are used alone, and this phenomenon is remarkable when the azo dye and the anthraquinone dye are blended.

However, current dichroic dyes are generally yellow-based,
Red is excellent in azo dyes, and blue is excellent in anthraquinone dyes.Therefore, especially in contrast to hues that need to be mixed with yellow, red and blue dyes such as black, brown and dark blue, It is difficult to realize long life and stability at low temperature.

(Problems to be Solved by the Invention) 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 Problems) As a result of earnest studies to achieve such an object, the present inventors found that
The present invention has been completed by finding a composition having excellent contrast, longevity and stability at low temperature. That is, the present invention is directed to at least one azo dichroic dye represented by the following general formulas [I] and [II], at least one anthraquinone dichroic dye represented by the following general formula [III], and the following general formulas: A liquid crystal composition containing at least one anthraquinone-based dichroic dye represented by the formulas [IV] and [V], and at least one of the liquid crystal compositions carried between transparent electrode substrates. Exists in the liquid crystal display element.

(In the formula, R ¹ represents a hydrogen atom, an alkyl group, an alkoxyalkyl group, an alkoxy group, R ² represents an alkyl group, an alkoxyalkyl group, an arylmethyl group, R ^{3 to} R ⁵ represent a hydrogen atom,
A methyl group, a methoxy group, a halogen atom, or R ⁴
And R ⁵ may be bonded to each other to form an aromatic ring when they are substituted on adjacent carbon atoms. ) (In the formula, R ⁶ and R ⁷ represent a hydrogen atom, an alkyl group, an alkoxyalkyl group or an alkoxy group.) (In the formula, R ⁸ and R ⁹ represent a hydrogen atom, an alkyl group, an alkoxyalkyl group, or an alkoxy group.) (In the formula, R ¹⁰ represents an alkyl group, an alkoxyalkyl group,
Indicates an alkoxy group. ) (In the formula, R ¹¹ and R ¹² represent a hydrogen atom, an alkyl group, an alkoxyalkyl group or an alkoxy group.) Of these, general formulas [I], [II], [III], [IV] and [V] A liquid crystal composition and a liquid crystal display device each containing at least one of these are particularly useful, and display such as black and brown having excellent contrast, life, and stability at low temperatures can be realized.

The present invention will be described in more detail by the general formulas [I] to [IV]
Examples of the alkyl group represented by R ¹ and R ^{6 to} R ¹² include a methyl group, an ethyl group, a linear or branched propyl group, a butyl group, a pentyl group, a hexyl group, an octyl group, a nonyl group, and dodecyl. Examples of the alkoxy group include methoxyethyl group, butoxyethyl group, methoxypropyl group, butoxypropyl group, and the like, and examples of the alkoxy group include methoxy group, ethoxy group, linear or branched propoxy group. Group, butoxy group,
Examples thereof include a pentoxy group and an octoxy group.

Examples of the alkyl group represented by R ² in the general formula [I] include a methyl group, an ethyl group, a linear or branched propyl group, a butyl group, a pentyl group, a hexyl group, an octyl group,
Examples thereof include nonyl group and dodecyl group, examples of alkoxyalkyl group include methoxyethyl group, butoxyethyl group, methoxypropyl group and butoxypropyl group, and examples of arylmethyl group include phenylmethyl group and butylphenylmethyl group. , Octylphenylmethyl group, butoxyphenylmethyl group, octyloxyphenylmethyl group, chlorophenylmethyl group and the like.

Further, R ^{3 to} R ⁵ in the general formula [I] are hydrogen atoms,
Examples thereof include a methyl group, a methoxy group, or a halogen atom such as a fluorine atom, a chlorine atom or a bromine atom, and when R ⁴ and R ⁵ are substituted on adjacent carbon atoms, they are linked to each other to form a benzene ring. And the like may form an aromatic ring.

The liquid crystal substance used in the present invention has the following general formula (In the formula, R ¹³ and R ¹⁴ 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 group, alkoxycarbonyl group, alkoxyalkoxycarbonyl group, alkylphenoxycarbonyl group, alkoxyalkylphenoxycarbonyl group, alkoxyphenoxycarbonyl group, alkylcyclohexyloxycarbonyl group, alkylcyclohexyl group Enoxycarbonyl group, cyanophenoxycarbonyl group, halogenophenoxycarbonyl group, alkylphenylalkyl group, alkoxyalkylphenylalkyl group, alkoxy Represents an enylalkyl group, an alkylcyclohexylalkyl group, an alkoxyalkoxycyclohexylalkyl group, an alkylcyclohexylphenylalkyl group, or a cyanophenylalkyl group, which may have an optically active center in the alkyl chain or the alkoxy chain.) Liquid crystal substances such as a simple substance of a compound to be used or a mixture thereof are included.

In addition, the liquid crystal mixture 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 can be easily prepared by dissolving the dye represented by the structural formulas [I] to [V] in the liquid crystal substance.

A display device in which the guest-host effect is applied by supporting at least one of the liquid crystal compositions prepared in this way between transparent electrode substrates [Matsumoto Shoichi, Tsunoda City "Latest Liquid Crystal Technology" Industrial Research Committee , 34 (1983), JLFergason, S
ID85 Digest, 68 (1985), etc.] can be constructed.

Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited to the following examples as long as the gist thereof is not exceeded.

Example 1 1.17 g of dye [I-1] represented by the following structural formula And a dye represented by the following structural formula [II-1] 0.45 g And a dye represented by the following structural formula [III-1] 1.49 g And a dye represented by the following structural formula [IV-1] 1.35 g And 1.04 g of the dye [V-1] represented by the following structural formula Was dissolved 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-1565 (manufactured by E.MERCK) to prepare a liquid crystal composition-I.

This is composed of a glass plate with a transparent electrode that has been homogeneously oriented by rubbing after coating and curing a polyimide resin,
Encapsulated in a cell of 9 μm in gear gap configured to face the orientation-treated surfaces, the absorbance A _″ for linearly polarized light parallel to the orientation direction and the absorbance A _⊥ for vertically polarized light were measured, As a result of calculating the order parameter S from 593n
At m, 500 nm and 467 nm were 0.75, 0.77 and 0.76, respectively.

Liquid crystal composition-1 and the cell in which it was enclosed were stored at -20 ° C for 10
As a result of leaving it for 00 hours, no particular abnormality such as precipitation of dye was observed.

Further, a light resistance test was carried out with a fade meter (carbon arc light source) using a cell in which the liquid crystal composition-I was enclosed. As a result, a hue change after 100 hours: ΔE (L ^* a ^* b
^* Method) was 4.9 g or less, and the rate of increase in current value: I / I ₀ (applied voltage: 5 V, 32 Hz) was 5.1 times.

(Comparative Example) Dye [VI] represented by the following structural formula in place of the dye [III-1] in the liquid crystal composition-1 A liquid crystal composition prepared by using 2.4 g was similarly enclosed in a cell and subjected to a light resistance test. As a result, the hue change after 100 hours: ΔE (L ^* a ^* b ^* method) was 14, and the current value was The rate of increase: I / I ₀ (applied voltage: 5V, 32Hz) was 8.3 times.

Example 2 Dyes [I-1] to [I-3] represented by the following structural formulas [I-1] R ¹ : C ₄ H ₉ (n) R ² : OC ₇ H ₁₅ (n) 0.39g [I-2] R ¹ : C ₈ H ₁₇ (n) R ² : OC ₇ H ₁₅ ( n) 0.43 g [I-3] R ¹ : C ₈ H ₁₇ (n) R ² : OC ₅ H ₁₁ (n) 0.41 g and dyes [II-2] to [II-
3] [II-2] R ⁶ : C ₄ H ₉ (n) R ⁷ : OC ₄ H ₉ (n) 0.25 g [II-3] R ⁶ : C ₄ H ₉ (n) R ⁷ : OC ₅ H ₁₁ ( n) 0.25 g and dyes represented by the following structural formulas [III-1] to [III-
3] [III-1] R ⁸ : C ₄ H ₉ (n) R ⁹ : CH ₃ 0.30g [III-2] R ⁸ : C ₇ H ₁₅ (n) R ⁹ : CH ₃ 0.64g [III-3] R ⁸ : C ₈ H ₁₇ (n) R ⁹ : CH ₃ 0.66 g and dyes represented by the following structural formulas [IV-1] to [IV-
3] [IV-1] R ¹⁰ : C ₄ H ₉ (n) 0.58 g [IV-2] R ¹⁰ : C ₆ H ₁₃ (n) 0.21 g [IV-3] R ¹⁰ : C ₈ H ₁₇ (n) 0.66 g and dyes represented by the following structural formulas [V-2] to [V-
3] [V-2] R ¹¹ : C ₄ H ₉ (n) R ¹² : OC ₄ H ₉ (n) 0.52g [V-3] R ¹¹ : C ₄ H ₉ (n) R ¹² : OC ₈ H ₁₇ ( n) 0.57
A liquid crystal composition-II was prepared by dissolving 100 g of a liquid crystal mixture containing a phenylcyclohexane compound as a main component, which was marketed under the trade name ZLI-1565 (manufactured by E.MERCK).

This is composed of a glass plate with a transparent electrode that has been homogeneously oriented by rubbing after coating and curing a polyimide resin,
Encapsulated in a cell of 9 μm in gear gap configured to face the orientation-treated surfaces, the absorbance A _″ for linearly polarized light parallel to the orientation direction and the absorbance A _⊥ for vertically polarized light were measured, As a result of calculating the order parameter S from 593n
At m, 500 nm and 467 nm were 0.75, 0.77 and 0.76, respectively.

The liquid crystal composition-II and the cell in which it was enclosed were stored at -20 ° C for 10
As a result of leaving it for 00 hours, no particular abnormality such as precipitation of dye was observed.

Further, a light resistance test was carried out with a fade meter (carbon arc light source) using a cell in which the liquid crystal composition-II was enclosed. As a result, a hue change after 100 hours: ΔE (L ^* a ^* b
^* Method) was 4.9 or less, and the rate of increase in current value: I / I ₀ (applied current: 5 V, 32 Hz) was 5.1 times.

Comparative Example Dyes [III-1] to [III-3] in Liquid Crystal Composition-II
Dye represented by the following structural formula instead of A liquid crystal composition prepared by using 2.4 g was similarly enclosed in a cell and subjected to a light resistance test. As a result, the hue change after 100 hours: ΔE (L ^* a ^* b ^* method) was 14, and the current value was The rate of increase: I / I ₀ (applied voltage: 5V, 32Hz) was 8.3 times.

Example 3 Dyes [I-1] to [I-3] represented by the following structural formulas [I-1] R ¹ : C ₄ H ₉ (n) R ² : OC ₇ H ₁₅ (n) 0.39g [I-2] R ¹ : C ₈ H ₁₇ (n) R ² : OC ₇ H ₁₅ ( n) 0.43 g [I-3] R ¹ : C ₈ H ₁₇ (n) R ² : OC ₅ H ₁₁ (n) 0.41 g and dyes [II-2] to [II-
3] [II-2] R ⁶ : C ₄ H ₉ (n) R ⁷ : OC ₄ H ₉ (n) 0.25 g [II-3] R ⁶ : C ₄ H ₉ (n) R ⁷ : OC ₅ H ₁₁ ( n) 0.26 g and dyes represented by the following structural formulas [III-1] to [III-
3] [III-1] R ⁸ : C ₄ H ₉ (n) R ⁹ : CH ₃ 0.30g [III-2] R ⁸ : C ₇ H ₁₅ (n) R ⁹ : CH ₃ 0.64g [III-3] R ⁸ : C ₈ H ₁₇ (n) R ⁹ : CH ₃ 0.66 g and dyes represented by the following structural formulas [IV-1] to [IV-
3] [IV-1] R ¹⁰ : C ₄ H ₉ (n) 0.58 g [IV-2] R ¹⁰ : C ₆ H ₁₃ (n) 0.21 g [IV-3] R ¹⁰ : C ₈ H ₁₇ (n) 0.66 g and dyes represented by the following structural formulas [V-2] to [V-
3] [V-2] R ¹¹ : C ₄ H ₉ (n) R ¹² : OC ₄ H ₉ (n) 0.52g [V-3] R ¹¹ : C ₄ H ₉ (n) R ¹² : OC ₈ H ₁₇ ( n) 0.57
Liquid crystal mixture containing phenyl cyclohexane compound as the main component, marketed under the trade name 9170 (manufactured by Chitso Co.)
Liquid Crystal Composition-III was prepared by dissolving it in 100 g.

This is composed of a glass plate with a transparent electrode that has been homogeneously oriented by rubbing after coating and curing a polyimide resin,
Encapsulated in a cell of 9 μm in gear gap configured to face the orientation-treated surfaces, the absorbance A _″ for linearly polarized light parallel to the orientation direction and the absorbance A _⊥ for vertically polarized light were measured, As a result of calculating the order parameter S from 594n
m, 498 nm and 464 nm were 0.76, 0.76 and 0.77, respectively.

Liquid crystal composition-III and the cell in which it was enclosed were stored at -20 ° C for 1
As a result of being left for 000 hours, no particular abnormality such as precipitation of pigment was observed.

Further, a light resistance test was carried out with a fade meter (carbon arc light source) using a cell in which the liquid crystal composition-III was enclosed. As a result, a hue change after 100 hours: ΔE (L ^* a ^*
The b ^* method) was 4.0 or less, and the rate of increase in current value: I / I ₀ (applied voltage: 5 V, 32 Hz) was 2.1 times.

(Comparative Example) Dyes [III-1] to [III- in Liquid Crystal Composition-III
Dye represented by the following structural formula instead of 3] [VI] A liquid crystal composition prepared by using 2.4 g was similarly enclosed in a cell and subjected to a light resistance test. As a result, a hue change after 100 hours: ΔE (L ^* a ^* b ^* method) was 11.3, and a current value was The rate of increase: I / I ₀ (applied voltage: 5V, 32Hz) was 4.4 times.

Example 4 Dyes [I-1] to [I-3] represented by the following structural formulas [I-1] R ¹ : C ₄ H ₉ (n) R ² : CO ₇ H ₁₅ (n) 0.40 g [I-2] R ¹ : C ₈ H ₁₇ (n) R ² : CO ₇ H ₁₅ ( n) 0.44 g [I-3] R ¹ : C ₈ H ₁₇ (n) R ² : CO ₅ H ₁₁ (n) 0.42 g and dyes [II-2] to [II-] represented by the following structural formula.
3] [II-2] R ⁶ : C ₄ H ₉ (n) R ⁷ : CO ₄ H ₉ (n) 0.25 g [II-3] R ⁶ : C ₄ H ₉ (n) R ⁷ : CO ₅ H ₁₁ ( n) 0.26 g and dyes represented by the following structural formulas [III-1] to [III-
3] [III-1] R ⁸ : C ₄ H ₉ (n) R ⁹ : CH ₃ 0.30g [III-2] R ⁸ : C ₇ H ₁₅ (n) R ⁹ : CH ₃ 0.65g [III-3] R ⁸ : C ₈ H ₁₇ (n) R ⁹ : CH ₃ 0.66 g and dyes represented by the following structural formulas [IV-1] to [IV-
3] [IV-1] R ¹⁰ : C ₄ H ₉ (n) 0.64g [IV-2] R ¹⁰ : C ₆ H ₁₃ (n) 0.34g [IV-3] R ¹⁰ : C ₈ H ₁₇ (n) 0.73 g and dyes represented by the following structural formulas [V-2] to [V-
3] [V-2] R ¹¹ : C ₄ H ₉ (n) R ¹² : OC ₄ H ₉ (n) 0.60 g [V-3] R ¹¹ : C ₄ H ₉ (n) R ¹² : OC ₈ H ₁₇ ( n) 0.66
g was dissolved in 100 g of a liquid crystal mixture containing a phenylcyclohexane-based compound as a main component, which was commercially available under the trade name ZLI-1565 (manufactured by E.MERCK) to prepare a liquid crystal composition-IV.

This is composed of a glass plate with a transparent electrode that has been homogeneously oriented by rubbing after coating and curing a polyimide resin,
Encapsulated in a cell of 9 μm in gear gap configured to face the orientation-treated surfaces, the absorbance A _″ for linearly polarized light parallel to the orientation direction and the absorbance A _⊥ for vertically polarized light were measured, As a result of calculating the order parameter S from 593n
At m, 504 nm and 467 nm were 0.75, 0.77 and 0.76, respectively.

Liquid crystal composition-IV and the cell in which it was enclosed were stored at -20 ° C for 10
As a result of leaving it for 00 hours, no particular abnormality such as precipitation of dye was observed.

Further, a light resistance test was carried out with a fade meter (carbon arc light source) using a cell in which the liquid crystal composition-IV was enclosed. As a result, a hue change after 100 hours: ΔE (L ^* a ^* b
^* Method) was 4.9 or less, and the rate of increase in current value: I / I ₀ (applied voltage: 5 V, 32 Hz) was 5.1 times.

(Effects of the Invention) According to the present invention, a liquid crystal composition capable of obtaining various hues by blending a yellow or red azo dichroic dye and a blue anthraquinone dichroic dye In addition, in a display element using the same, high contrast, long life, and stability at low temperature can be obtained.

Claims (2)

[Claims] 1. An azo dichroic dye represented by the following general formula [I] or [II];
A liquid crystal composition comprising at least one anthraquinone dichroic dye represented by I] and at least one anthraquinone dichroic dye represented by the following general formula [IV] or [V]. (In the formula, R ¹ represents a hydrogen atom, an alkyl group, an alkoxyalkyl group, an alkoxy group, R ² represents an alkyl group, an alkoxyalkyl group, an arylmethyl group, R ^{3 to} R ⁵ represent a hydrogen atom,
A methyl group, a methoxy group, a halogen atom, or R ⁴
When R ^{5 s} are substituted on adjacent carbon atoms, they may be linked to each other to form an aromatic ring. ) (In the formula, R ⁶ and R ⁷ represent a hydrogen atom, an alkyl group, an alkoxyalkyl group or an alkoxy group.) (In the formula, R ⁸ and R ⁹ represent a hydrogen atom, an alkyl group, an alkoxyalkyl group, or an alkoxy group.) (In the formula, R ¹⁰ represents an alkyl group, an alkoxyalkyl group,
Indicates an alkoxy group. ) (In the formula, R ¹¹ and R ¹² represent a hydrogen atom, an alkyl group, an alkoxyalkyl group, or an alkoxy group.) 2. A liquid crystal display device having a liquid crystal composition supported between electrode substrates, at least one of which is transparent, and an azo dichroic dye represented by the following general formulas [I] and [II] as the liquid crystal composition. From the anthraquinone dichroic dye represented by the following general formula [III] and at least one anthraquinone dichroic dye represented by the following general formulas [IV] and [V]. A liquid crystal display device comprising the liquid crystal composition according to claim 1. (In the formula, R ¹ represents a hydrogen atom, an alkyl group, an alkoxyalkyl group, an alkoxy group, R ² represents an alkyl group, an alkoxyalkyl group, an arylmethyl group, R ^{3 to} R ⁵ represent a hydrogen atom,
A methyl group, a methoxy group, a halogen atom, or R ⁴
And R ⁵ are substituted with adjacent carbon atoms, they may be linked to each other to form an aromatic ring. ) (In the formula, R ⁶ and R ⁷ represent a hydrogen atom, an alkyl group, an alkoxyalkyl group or an alkoxy group.) (In the formula, R ⁸ and R ⁹ represent a hydrogen atom, an alkyl group, an alkoxyalkyl group, or an alkoxy group.) (In the formula, R ¹⁰ represents an alkyl group, an alkoxyalkyl group,
Indicates an alkoxy group. ) (In the formula, R ¹¹ and R ¹² represent a hydrogen atom, an alkyl group, an alkoxyalkyl group, or an alkoxy group.)