JPH0788508B2 - Liquid crystal composition and liquid crystal display device - Google Patents

Description

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

(Prior Art) A liquid crystal display device utilizing a guest-host effect in which a dichroic dye is added to liquid crystal has 1) a wide viewing angle, 2) various dyes can be easily realized by selecting a 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 liquid crystal display element particularly suitable for medium to large-sized display.

Conventionally, it has been difficult for a liquid crystal display device utilizing a guest-host effect in which a dichroic dye is added to liquid crystal to simultaneously satisfy high contrast, high light-shielding property, 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 blended, photodegradation of either dye is often promoted. 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, the current dichroic dyes are generally yellow-based, red-based azo dyes are excellent, and blue-based anthraquinone-based dyes are excellent, so black, brown,
With respect to hues that require the addition of yellow, red, and blue dyes such as dark blue, there is a problem in that it is difficult to achieve contrast, long life, and stability at low temperatures.

(Problems to be Solved by the Invention) In the present invention, even if an anthraquinone type dichroic dye is used for a red type dichroic dye, which is generally superior to azo dyes, the combination of the dyes is made a specific combination. It is based on the new finding that the contrast, light-shielding property, stability at low temperature, and in particular when using an ultraviolet cut filter that cuts light with a wavelength of 400 nm or less, can significantly improve light resistance, An object of the present invention is to provide a color liquid crystal composition capable of solving the above conventional problems and a liquid crystal display device using the same.

(Means for Solving the Problem) The present invention is to provide a liquid crystal composition excellent in contrast, high light-shielding property, stability at low temperature, and light resistance, and a liquid crystal display device using the same, and the gist thereof is The liquid crystal composition contains at least one dichroic dye represented by each of the following groups (A), (B) and (C), and in the group (B), a general formula (II) described later is used. And a liquid crystal display device in which at least one of the liquid crystal compositions is carried between transparent electrode substrates.

Group (A) An azo-based dichroic dye represented by the following general formula [I].

(In the formula, R ¹ and R ² represent a hydrogen atom, an alkyl group, an alkoxyalkyl group, an alkoxy group, an arylmethyl group,
R ^{3 to} R ⁵ represent a hydrogen atom, a methyl group, a methoxy group or a halogen atom, or R ⁴ and R ⁵ may be linked to each other to form an aromatic ring. ) (B) Group Anthraquinone-based dichroic dyes represented by the following general formulas [II] and [III].

(In the formula, R ⁶ and R ⁷ represent a hydrogen atom, an alkyl group, a substituted or unsubstituted cycloalkyl group, an aryl group, an alkoxy group, an alkoxyalkyl group, or an aralkyl group.) (In the formula, R ⁸ and R ⁹ represent a hydrogen atom, an alkyl group, an alkoxyalkyl group, an alkoxy group, a substituted or unsubstituted cycloalkyl group, an aryl group, or an aralkyl group.) (C) Group The following general formula [IV ] And an anthraquinone type dichroic dye represented by the general formula [V].

(In the formula, R ¹⁰ represents a hydrogen atom, an alkyl group, an alkoxyalkyl group, an alkoxy group, a substituted or unsubstituted cycloalkyl group, an aryl group or an aralkyl group.) (In the formula, R ¹¹ and R ¹² represent a hydrogen atom, an alkyl group, an alkoxyalkyl group, an alkoxy group, a substituted or unsubstituted cycloalkyl group, an aryl group or an aralkyl group.) The present invention will be described in more detail. , R ¹ and R ² are hydrogen atoms; linear or branched alkyl groups such as methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, octyl group, nonyl group and dodecyl group; methoxy Alkoxyalkyl groups such as ethyl group, ethoxyethyl group, methoxypropyl group, butoxypropyl group; linear or branched alkoxy groups such as methoxy group, ethoxy group, propoxy group, butoxy group, pentoxy group, octoxy group; phenyl Methyl group, butylphenylmethyl group, octylphenylmethyl group, butoxyphenylmethyl group,
Examples thereof include arylmethyl groups such as octyloxyphenylmethyl group and chlorophenylmethyl group.

Examples of R ^{3 to} R ⁵ include a hydrogen atom, a methyl group, a methoxy group or a halogen atom such as a fluorine atom, a chlorine atom and a bromine atom, or R ⁴ and R ⁵ are linked to each other to form an aromatic ring. May be.

Specific examples of the substituent represented by R ^{6 to} R ¹² include a hydrogen atom;
A linear or branched alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, an octyl group, a nonyl group or a dodecyl group; a methoxy group, an ethoxy group, a propoxy group, a butoxy group, Linear or branched alkoxy group such as pentoxy group, octoxy group; alkoxyalkyl group such as methoxyethyl group, ethoxyethyl group, methoxypropyl group, butoxypropyl group; phenyl group, linear or branched C ₁ An aryl group such as a phenyl group substituted by an alkyl group or an alkoxy group of -C ₈ ; a benzyl group, a phenethyl group (these groups are linear or branched C ₁ -C ₈ alkyl groups or alkoxy groups; It is substituted with a straight-chain or alkyl or alkoxy group of branched C ₁ -C _8; aralkyl groups such as may) be substituted There cyclohexyl (specifically, butylcyclohexyl group, octylcyclohexyl group, butyl oxy cyclohexyl group) include substituted or unsubstituted cycloalkyl groups such as.

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, and a cyanophenyl group. , Cyano group, halogen atom, alkoxycarbonyl group, alkoxyalkoxycarbonyl group, alkylphenoxycarbonyl group, alkoxyalkylphenoxycarbonyl group, alkoxyphenoxycarbonyl group, alkylcyclohexyloxycarbonyl group, alkylcyclohexyloxycarbonyl group, alkylcyclohexylphenoxycarbonyl group, Cyanophenoxycarbonyl group, halogenphenoxycarbonyl group, alkylphenylalkyl group, Job Shi alkylphenyl group, alkoxyphenyl group, an alkyl cyclohexyl group, alkoxyalkoxy cyclohexyl group, an alkyl phenyl alkyl group, a cyanophenyl group, an alkyl chain,
It may have an optically active center in the alkoxy chain. Also, R
The phenyl group or phenoxy group in ¹³ , R ¹⁴ may be further substituted with a halogen atom such as a fluorine atom or a chlorine atom. Further, X represents a hydrogen atom, a fluorine atom or a chlorine atom. ) A liquid crystal substance such as a simple substance of a compound represented by or a mixture thereof.

Further, 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 dyes represented by the general formulas [I] to [V] in the liquid crystal substance.

By supporting the liquid crystal composition prepared in this manner between the electrode substrates, at least one of which is transparent, it is possible to construct a liquid crystal display device to which the guest-host effect is applied.

This is “Shoichi Matsumoto, Ryo Kakuda“ Latest Liquid Crystal Technology ”Industry Study Group, 34 (1983), J, L Fergason, SID85 Digest, 68 (198
5) etc. ”.

(Examples) 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 was evaluated by the order parameter (S) of the dye compound obtained from the following formula.

Where A And A_⊥For the alignment direction of the liquid crystal,
The absorbance of the dye for parallel and vertically polarized light
is there.

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

Example 1 3.09 g of dye [I-1] represented by the following structural formula And a dye [II-1] represented by the following structural formula: 2.80 g And a dye represented by the following structural formula [III-1] 2.00 g And 3.01 g of the dye [IV-1] represented by the following structural formula And 2.00 g of a 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 made of a glass plate with a transparent electrode that is homogeneously oriented by rubbing it after applying and curing a polyimide resin, and a gap formed so that the orientation-treated surfaces face each other.
A 99 μm cell was sealed and a liquid crystal display device was prepared.

The order parameter (S) of this liquid crystal display device was calculated using the above formula, and the results were 632 nm, 580 nm, 535 nm and 4
At 65 nm were 0.75, 0.76, 0.73 and 0.77 respectively.

A liquid crystal composition-I and a liquid crystal display device encapsulating the same are
As a result of leaving at 1000 ° C. for 1000 hours, no abnormality such as precipitation of dye was found.

In addition, as a result of performing a light resistance test with a fade meter (carbon arc light source) using a liquid crystal display device in which the liquid crystal composition-I is enclosed, a hue change after 100 hours: ΔE (L
^{* A *} b ^* method) is less than 1.5, and the rate of increase in current value: I / Io
(Applied voltage: 5V 32Hz) was 6.0 times.

Example 2 3.10 g of dye [I-1] represented by the following structural formula And 2.40 g of the dye [II-1] represented by the following structural formula And a dye represented by the following structural formula [II-2] 0.50 g And 0.45 g of the dye [III-1] represented by the following structural formula And 0.83 g of the dye [III-2] represented by the following structural formula And a dye represented by the following structural formula [III-3] 0.87 g And 2.50 g of a dye [IV-1] represented by the following structural formula And 1.50 g of a dye [V-1] represented by the following structural formula And 1.25 g of a dye [V-2] represented by the following structural formula A liquid crystal mixture containing a phenylcyclohexane compound as a main component, which is commercially available under the trade name 9170 (manufactured by Chisso Corporation)
Liquid Crystal Composition-II was prepared by dissolving it in 100 g.

This is coated with a polyimide resin and cured, and then rubbed to form a liquid crystal display device by enclosing it in a cell with a gap of 9 μm, which is made of a glass plate with a transparent electrode subjected to a homogeneous alignment treatment, and the alignment treatment surfaces face each other. did.

As a result of calculating the order parameter (S) of this liquid crystal display device using the above-mentioned formula, it was 0.75, 0.75 and 0.77 at 635 nm, 575 nm and 465 nm, respectively.

A liquid crystal composition-II and a liquid crystal display device enclosing the liquid crystal composition-
As a result of leaving at 1000 ° C. for 1000 hours, no abnormality such as precipitation of dye was found.

In addition, as a result of performing a light resistance test with a fade meter (carbon arc light source) using a liquid crystal display element in which the liquid crystal composition-II is enclosed, a hue change after 100 hours: ΔE (L
^{* A *} b ^* method) is less than 1.5, and the rate of increase in current value: I / Io
(Applied voltage: 5V 32Hz) was 5.0 times.

Example 3 0.55 g of dye [I-1] represented by the following structural formula And 0.60 g of a dye [I-2] represented by the following structural formula And 0.65 g of a dye [I-3] represented by the following structural formula And a dye represented by the following structural formula [II-1] 1.20 g And a dye represented by the following structural formula [II-2] 0.25 g And 0.22 g of the dye [III-1] represented by the following structural formula And 0.41 g of the dye [III-2] represented by the following structural formula And a dye represented by the following structural formula [III-3] 0.44 g And 1.00 g of a dye [IV-1] represented by the following structural formula And a dye represented by the following structural formula [IV-2] 0.25 g And 1.10 g of a dye [IV-3] represented by the following structural formula And 0.75 g of the dye [V-1] represented by the following structural formula And 0.64 g of a dye [V-2] represented by the following structural formula Was dissolved in 100 g of a liquid crystal mixture containing a phenylcyclohexane-based 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-III.

This is made of a glass plate with a transparent electrode that is homogeneously oriented by rubbing it after applying and curing a polyimide resin, and a gap formed so that the orientation-treated surfaces face each other.
A 99 μm cell was sealed and a liquid crystal display device was prepared.

The order parameter (S) of this liquid crystal display device was calculated using the above formula, and the results were 632 nm, 580 nm, 535 nm and 4
At 65 nm were 0.74, 0.75, 0.73 and 0.77 respectively.

A liquid crystal composition-III and a liquid crystal display device in which the liquid crystal composition is enclosed-2
As a result of standing for 1000 hours at 0 ° C, no abnormality such as precipitation of dye was observed.

In addition, a light resistance test was conducted with a fade meter (carbon arc light source) using a liquid crystal display device in which the liquid crystal composition-III was enclosed. As a result, a hue change after 100 hours: ΔE
(L ^* a ^* b ^* method) is 1.2 or less, and the increase rate of the current value is:
I / Io (applied voltage: 5V 32Hz) was 5.5 times.

(Effect of the invention) The liquid crystal composition of the present invention is excellent in contrast, light-shielding property and stability at low temperature, and a liquid crystal display device using the liquid crystal composition has high contrast, high light-shielding property, long life, and low temperature. It has stability and various hues, and is excellent in light resistance particularly by using an ultraviolet cut filter that cuts light having a wavelength of 400 nm or less, and is very useful as a color liquid crystal display device compared with the conventional ones.

Claims (2)

[Claims] 1. A liquid crystal composition containing at least one dichroic dye represented by each of the following groups (A), (B) and (C), and (B) group which will be described later. Formula (II)
A liquid crystal composition, which necessarily comprises at least one kind of the dyes represented by Group (A) An azo-based dichroic dye represented by the following general formula [I]. (In the formula, R ¹ and R ² represent a hydrogen atom, an alkyl group, an alkoxyalkyl group, an alkoxy group, an arylmethyl group,
R ^{3 to} R ⁵ represent a hydrogen atom, a methyl group, a methoxy group or a halogen atom, or R ⁴ and R ⁵ may be linked to each other to form an aromatic ring. ) (B) Group Anthraquinone-based dichroic dyes represented by the following general formulas [II] and [III]. (In the formula, R ⁶ and R ⁷ represent a hydrogen atom, an alkyl group, a substituted or unsubstituted cycloalkyl group, an aryl group, an alkoxy group, an alkoxyalkyl group, or an aralkyl group.) (In the formula, R ⁸ and R ⁹ represent a hydrogen atom, an alkyl group, an alkoxyalkyl group, an alkoxy group, a substituted or unsubstituted cycloalkyl group, an aryl group, or an aralkyl group.) (C) Group The following general formula [IV ] And an anthraquinone type dichroic dye represented by the general formula [V]. (In the formula, R ¹⁰ represents a hydrogen atom, an alkyl group, an alkoxyalkyl group, an alkoxy group, a substituted or unsubstituted cycloalkyl group, an aryl group or an aralkyl group.) (In the formula, R ¹¹ and R ¹² represent a hydrogen atom, an alkyl group, an alkoxyalkyl group, an alkoxy group, a substituted or unsubstituted cycloalkyl group, an aryl group, or an aralkyl group.) 2. A liquid crystal display device comprising a liquid crystal composition supported between electrode substrates, at least one of which is transparent, wherein the liquid crystal composition is represented by the following groups (A), (B) and (C). A liquid crystal composition containing at least one dichroic dye from each group, and the group (B) necessarily contains at least one dye represented by the general formula (II) described later. Liquid crystal display device. Group (A) An azo-based dichroic dye represented by the following general formula [I]. (In the formula, R ¹ and R ² represent a hydrogen atom, an alkyl group, an alkoxyalkyl group, an alkoxy group, an arylmethyl group,
R ^{3 to} R ⁵ represent a hydrogen atom, a methyl group, a methoxy group or a halogen atom, or R ⁴ and R ⁵ may be linked to each other to form an aromatic ring. ) (B) Group Anthraquinone-based dichroic dyes represented by the following general formulas [II] and [III]. (In the formula, R ⁶ and R ⁷ represent a hydrogen atom, an alkyl group, a substituted or unsubstituted cycloalkyl group, an aryl group, an alkoxy group, an alkoxyalkyl group, or an aralkyl group.) (In the formula, R ⁸ and R ⁹ represent a hydrogen atom, an alkyl group, an alkoxyalkyl group, an alkoxy group, a substituted or unsubstituted cycloalkyl group, an aryl group, or an aralkyl group.) (C) Group The following general formula [IV ] And an anthraquinone type dichroic dye represented by the general formula [V]. (In the formula, R ¹⁰ represents a hydrogen atom, an alkyl group, an alkoxyalkyl group, an alkoxy group, a substituted or unsubstituted cycloalkyl group, an aryl group or an aralkyl group.) (In the formula, R ¹¹ and R ¹² represent a hydrogen atom, an alkyl group, an alkoxyalkyl group, an alkoxy group, a substituted or unsubstituted cycloalkyl group, an aryl group, or an aralkyl group.)