JPH02178391A - Liquid crystal composition and display element using same composition - Google Patents

Abstract

PURPOSE:To obtain a color liquid crystal composition having especially excellent light resistance, further contrast and life, containing a liquid crystal substance and two kinds of anthraquinone-based two-tone dyestuffs. CONSTITUTION:The aimed composition containing (A) a liquid crystal substance and (B) (i) one or more of anthraquinone-based two-tone dyestuffs shown by formula I (R<1>-R<3> are H, halogen, alkyl, alkoxyalkyl, etc.; A is group shown by formula II-formula IV) and (ii) one or more of anthraquinone-based two-tone dyestuffs shown by formula V (R<4> and R<5> are H, halogen, alkyl, alkoxyalkyl, etc.).

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a liquid crystal composition and a display element using the same;
In particular, the present invention relates to a color liquid crystal composition and a display element having excellent light resistance.

(Prior Art) A display element that utilizes the guest-host effect of adding a dichroic dye to liquid crystal has 1) a wide viewing angle. 2) A variety of display colors can be easily realized by selecting dyes. 3) Since it does not necessarily require a polarizing plate, it can provide a bright display, and is therefore attracting attention as a display element particularly suitable for medium to large-sized displays.

(Problems to be Solved by the Invention) Conventionally, however, it has been difficult for display elements that utilize the guest-host effect of adding dichroic dyes to liquid crystals to simultaneously satisfy high contrast, long life, and a variety of hues. The reason for this is that in addition to the lack of dichroic dyes that have excellent both dichroism and light resistance, when different types of dyes are combined, the photodegradation of one of the dyes, especially that caused by ultraviolet light, often accelerates. This results in lower light resistance than when the dye is used alone. There is a problem in that the deterioration caused by light that occurs in this way is observed as discoloration or fading, and is measured as an increase in current consumption. Therefore, conventionally, it has been difficult to achieve both contrast and long life when it comes to a variety of hues that require the combination of yellow and blue dichroic pigments such as green and yellow-green. was there.

An object of the present invention is to provide a color liquid crystal composition and a display element that can solve the above-mentioned conventional problems.

(Means for Solving the Problems) The present invention relates to a liquid crystal composition that is excellent in both contrast and life. That is, the present invention relates to a liquid crystal material and a compound having the following general formula (N and at least one anthraquinone dichroic dye represented by the general formula [■] (wherein R4 is a hydrogen atom, a halogen atom, an alkyl group, an alkoxyalkyl group, Represents a cyclohexyl group which may have an alkoxy group or an alkyl group, R5 is a hydrogen atom, a halogen atom,
It represents an alkyl group, an alkoxyalkyl group, an alkoxy group, a cyclohexyl group that may have an alkyl group, or a phenyl group that may have an alkyl group or an alkoxy group. ); and
The gist of the present invention is a display element in which the liquid crystal composition is supported between electrode substrates, at least one of which is transparent.

To explain the present invention in more detail, the above general 2N) to (I
R'-R' in I) includes a hydrogen atom; a halogen atom such as a fluorine atom, a chlorine atom, a bromine atom; a methyl group,
Straight-chain or branched alkyl groups such as ethyl, propyl, butyl, pentyl, hexyl, octyl, nonyl, dodecyl; methoxymethyl, butoxymethyl, methoxypropyl, ethoxyethyl linear or branched alkoxyalkyl groups such as butoxyethyl; linear or branched alkoxy groups such as methoxy, ethoxy, propoxy, butoxy, pentoxy, octoxy; cyclohexyl A cyclohexyl group which may have a linear or branched alkyl group such as a propylcyclohexyl group, a butylcyclohexyl group, a pentylcyclohexyl group, a hexylcyclohexyl group, an octylcyclohexyl group, and the above-mentioned general formula R5 in (II) is a hydrogen atom; a halogen atom such as a fluorine atom, a chlorine atom, a bromine atom; a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, an octyl group, a nonyl group, a dodecyl group, etc. Straight chain or branched alkyl group; straight chain or branched alkoxyalkyl group such as methoxymethyl group, butoxymethyl group, methoxypropyl group, ethoxyethyl group, butoxyethyl group; methoxy group, ethoxy linear or branched alkoxy groups such as propoxy group, butoxy group, pentoxy group, octoxy group; cyclohexyl group, propylcyclohexyl group, butylcyclohexyl group, pentylcyclohexyl group, hexylcyclohexyl group, octylcyclohexyl group Cyclohexyl group which may have a straight chain or branched alkyl group such as; alkyl group or alkoxy such as phenyl group, ethylphenyl group, butylphenyl group, octylphenyl group, butoxyphenyl group, octyloxyphenyl group; Examples include phenyl groups which may be substituted with other groups.

In addition, in each dye represented by general formulas (1) and (II), when it has a substituted cyclohexyl group, trans-
A 4-substituted cyclohexyl group is preferred.

As the liquid crystal substance used in the present invention, the following general (in the formula,
R6 and R' are alkyl group, alkoxyalkyl group, alkoxy group, alkylphenyl group, alkoxyalkylphenyl group, alkoxyphenyl group, alkylcyclohexyl group, alkoxyalkylcyclohexyl group, alkylcyclohexylphenyl group, cyanophenyl group, cyano group , halogen atom, alkoxycarbonyl group, alkoxyalkoxycarbonyl group, alkylphenoxycarbonyl group, alkoxyalkylphenoxycarbonyl group, alkoxyphenoxycarbonyl group, alkylcyclohexyloxycarbonyl group, alkoxycyclohexyloxycarbonyl group, alkylcyclohexylphenoxy Carbonyl group, cyanophenoxycarbonyl group, halogen phenoxycarbonyl group, alkylphenylalkyl group, alkoxyalkylphenylalkyl group, alkoxyphenylalkyl group, alkylcyclohexylalkyl group, alkoxyalkoxycyclohexylalkyl group, alkylcyclohexylphenylalkyl group group, cyanophenyl alkyl group, and may have an optically active center in the alkyl chain or alkoxy chain. Also, R6, R'
The phenyl group or phenoxy group therein may be substituted with a halogen atom such as a fluorine atom or a chlorine atom. or,
X represents a hydrogen atom or a halogen atom such as a fluorine atom or a chlorine atom. ) or a mixture thereof.

Further, the liquid crystal composition 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 structural formulas (1) to [■] in the liquid crystal substance described above.

A display element that applies the guest-host effect by supporting the liquid crystal composition prepared in this way between electrode substrates, at least one of which is transparent [Matsumoto Pressure-1, Ichiyoshi Kakuda, “
Latest Technology of Liquid Crystals” Industrial Research Group 34 (1983) J
, L.Fergason, SID 85 Dige
st 68 (1985) etc.).

〔Example〕

EXAMPLES The present invention will be specifically explained below using examples, but the present invention is not limited to the following examples unless it exceeds the gist thereof.

In addition, in the following examples, the quality of dichroism is determined by the order parameter (S) of the dye compound obtained from the following formula.
Evaluated by.

A//+2A where A// and A are the absorbance of the dye for light polarized parallel and perpendicular to the alignment direction of the liquid crystal, respectively.

Specifically, the order parameter (S) is
This is a value that indicates the display contrast of a host type liquid crystal display element, and theoretically, as this value approaches 1, the degree of residual color in white areas decreases, and a bright and clear display with high contrast becomes possible.

Furthermore, the dyes used in the following examples are listed in Table 1.

Note that the 4-substituted cyclohexyl group represents a trans-4-substituted cyclohexyl group.

Example 1 The following dichroic dye was used under the trade name ZLI-1565 (E, ME
A liquid crystal composition -1 was prepared by dissolving the liquid crystal composition in 100 g of a liquid crystal mixture whose main component was a phenylcyclohexane compound commercially available as (manufactured by RCK).

Dye (1-1) 2.80 g (II-131,65g (II-9) 0.87g This was coated with a polyimide resin, cured, and then rubbed to homogeneously align a glass plate with a transparent electrode. A liquid crystal display element was prepared by sealing the liquid crystal in a cell having a gap of 9 μm and having the alignment-treated surfaces facing each other.

The order parameter (S) of this liquid crystal display element was calculated to be 0.74 and 0.70 at 638 nm and 460 nm, respectively. As a result of carrying out a light resistance test using a fade meter (carbon arc light source) on a cell filled with liquid crystal composition -■, the hue change after 200 hours: ΔE1 (L"a"b9 method) was 3.3 or less. Yes, the rate of increase in current value is T/1. (Applied voltage: 5■, 32
Hz) was 3.0, and the absorbance change of each absorption peak (638 nm and 460 nn+) was 3.3% or less.

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

Dye (r-2) 1.52g Cl-3) 1.50g (1-4) 1.55g (II-2) 1.35g (II-3) 1.33g [■-1030, 20g (II-11) ) 0.30g (If-12) 0.30g Using this, a liquid crystal display element was created in the same manner as in Example 1.

As a result of calculating the order parameter (S) of this liquid crystal display element, 636nI11.600nm and 460nI
m, 0.74, 0.72 and 0.70 respectively
Met. As a result of carrying out a light resistance test using a fade meter (carbon arc light source) on a cell filled with liquid crystal composition -■, the hue change after 200 hours: ΔE" (L
'''a''l bm method) is 3°2 or less, and the rate of increase in current value I/ro <applied voltage: 5■, 32Hz) is 2.
7, and each absorption peak (636r+m, 600nm
and 460r+m), the change in absorbance was 3.3% or less.

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

Dye [1-6) [IT-4) [-5) ['1l-6) , 30g , 35g , 40g , 05g , 15g , 15g (II-9) 1.50g (II-10)
1.57 g A liquid crystal display element was prepared in the same manner as in Example 1.

The order parameter (S) of this liquid crystal display element was calculated to be 0.73 and 0.69 at 638 nm and 460 r+m, respectively. Liquid crystal composition-■
As a result of carrying out a light resistance test using a fade meter (carbon arc light #), the hue change after 200 hours: ΔE"(L"a"b1 method) was 2.8 or less, and the cell containing Value increase rate 1/1. (Applied voltage: 5■, 32
Hz) was 3.1, and the absorbance change of each absorption peak (638 nm and 460 r+m) was 3.2% or less.

Example 4 The following dichroic dye was used under the trade name ZL>1840 (E, MER
A liquid crystal composition (1) was prepared by dissolving the liquid crystal composition in 100 g of a liquid crystal mixture containing a phenylcyclohexane compound as a main component (manufactured by CK Corporation).

pigment (1-1) 2.10 g (1-2) 2.30 g (1-3) 1. OOg (n-7) 1.20g [ll-8]1. OOg A liquid crystal display element was produced from this in the same manner as in Example 1.

The order parameters (S) of this liquid crystal display element were calculated to be 0.74, 0.73 and 0169 at 636 nm, 597 nm and 467 nm, respectively. As a result of carrying out a light resistance test using a fade meter (carbon arc light source) on a cell filled with liquid crystal composition -■, the hue change after 200 hours: ΔEe (Lm
aIT be method) is 3.5 or less, the rate of increase in current value I/Io <applied voltage: 5, 32 Hz) is 3.2, and each absorption peak (636 nm, 597 nm and 46
The change in absorbance at 0 nm) was 3.1% or less.

Example 5 A liquid crystal composition -■ was prepared in the same manner as in Example 4, except that the following dichroic dye was used as the dye.

pigment (1-8) 1.30g (1-9) 0.85g (rV-13) 0.60g (TV-14) 0.70g (TV-15) 0.72g A liquid crystal display element was produced in the same manner as in Example 1.

The order parameter (S) of this liquid crystal display element was calculated to be 0.74 and 0.69 at 664 nm and 460n+n, respectively. Liquid crystal composition-V
As a result of carrying out a light resistance test using a fade meter (carbon arc light source), the hue change after 200 hours: ΔE"(L"a"b9 method) was 3.5 or less, and the current value Increase rate of 1/Io <applied voltage=5■, 3
2Hz) is 3.8, and each absorption peak (664nm
and 460 nm) was less than 4%.

(Effects of the Invention) As is clear from the above results, the color liquid crystal composition containing the specific combination of dichroic dyes of the present invention and the liquid crystal display element using the liquid crystal composition do not contain dichroic dyes. This technology takes advantage of the guest-host effect, which has excellent light resistance, and is particularly difficult to produce in a variety of hues such as green and yellow-green, which requires the combination of yellow and blue dichroic pigments. This has a remarkable effect of industrial value, making it possible to achieve both contrast and long life.

Claims (1)

[Claims] 1) Liquid crystal substance and the following general formula [I] ▲There are mathematical formulas, chemical formulas, tables, etc.▼-[I] (In the formula, R^1 to R^3 are hydrogen atoms, halogen atoms, alkyl A represents a cyclohexyl group that may have a group, an alkoxyalkyl group, an alkoxy group, or an alkyl group; At least one type of anthraquinone dichroic dye represented by the general formula [II]▲mathematical formula, chemical formula,
There are tables, etc. ▼-[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 that may have an alkyl group, and R^5 is Anthraquinone type represented by a hydrogen atom, a halogen atom, an alkyl group, an alkoxyalkyl group, an alkoxy group, a cyclohexyl group that may have an alkyl group, or a phenyl group that may have an alkyl group or an alkoxy group. A liquid crystal composition comprising at least one dichroic dye. 2) A liquid crystal display element comprising a liquid crystal composition supported between electrode substrates, at least one of which is transparent, characterized in that the liquid crystal composition according to claim 1 is used as the liquid crystal composition.