JPS591586A - Liquid crystal composition - Google Patents

Abstract

PURPOSE:To provide a liquid crystal composition containing specified liquid crystal compds., which has a wide liquid crystal temperature range, is less dependent on temperature, shows good response and is suitable for high-level time- division drive. CONSTITUTION:The liquid crystal composition contains (A) 10-40% m-dioxane liquid crystal compd. of formula I (where R1 is 3-5C straight-chain alkyl) (e.g., 2-p-cyanophenyl-5-n-propyl-1,3-m-dioxane), (B) 10-40% fluorocyclohexanecarboxylic acid ester liquid crystal compd. of formula II (where R2 is 3-7 C straight-chain alkyl) (e.g. 4-fluorophenyl trans-4'-n-pentylcyclohexanecarboxylic acid ester), (C) 2-20% PCH liquid crystal compd. of formula III (where R3 and R4 are 2-6C alkyl) having negative dielectric anisotropy [e.g. 4- (trans-4-propylhexyl)ethxoybenzene] and (D) an optically active substance (e.g. p-isopentyl-p'- cyano-biphenyl).

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a liquid crystal composition for time-division driving.

A liquid crystal display that displays an image G1 by aligning positive nematic liquid crystal in parallel between two glass substrates with transparent electrodes and applying and removing voltage to display pixels is a so-called field effect liquid crystal display. It is called a display device and has been widely used for displays such as calculators, clocks, games, measuring instruments, office equipment, etc., but recent market trends are such that liquid crystal displays can display more information. Demands on the body are increasing. One of the drive methods that meets these requirements is the time-division drive method (multiplex, drive).
Nowadays, liquid crystal display devices with high time-division driving are coming onto the market.

Accordingly, the emergence of a liquid crystal composition suitable for high-time division driving is desired, and the characteristics required for this are (1) steep voltage-luminance characteristics (low viscosity, low viscosity, etc.); It needs to be a warm crystal with characteristics such as (■) low temperature dependence (4) wide temperature range.

Furthermore, as driving voltages tend to be lowered, there is also a need for liquid crystal compositions having low voltage brightness characteristics.

It has poor steepness, making it unsuitable for practical use as a multi-segment liquid crystal, and the response speed is also lower than that of conventional biphenyl. The ester type has a relatively high viscosity, so the response speed is generally slow.The present invention was made to eliminate the above-mentioned problems. The purpose of this invention is to provide a liquid crystal composition that has excellent properties, and also has excellent sharpness and responsiveness even when the voltage is lowered. That is, the characteristics of the present liquid crystal composition include a metadioxane-based liquid crystal compound (Rs-CgX)ON) and a fluorocyclohexanecarboxylic acid ester-based liquid crystal compound (Rs-CgX)ON).
t -@rO-o-o-Ir) Negative n By mixing other liquid crystal compounds accordingly, a liquid crystal composition with excellent voltage-luminance characteristics and responsiveness can be obtained. Furthermore, if the composition is based on the above-mentioned liquid crystal composition, it is possible to achieve a considerably lower voltage without impairing steepness or response.

The present invention will be explained below with reference to Examples. Table 1 shows the liquid crystal composition ratios of Examples.

Example 1 is 2-P-cyanophenyl-5-ya proyl-1,3-metadioxane (hereinafter referred to as 0D-3, lj)
and 2-P-cyanophenyl-5-n-butyl-1,
3-metadioxane C or less 0D-4,! :Omitted. ) and 4-fluorophenyl-trans-4'-n pentylcyclohexanecarboxylic acid ester C or less 5HE]Z
It is abbreviated as ] and] 4-fluorophenyltrans 4
1-s heptylcyclohexanecarboxylic acid ester (hereinafter abbreviated as 7HPZ) and 4-(trans-4-pro5-bicyclohexyl)-ethoxybenzene (hereinafter abbreviated as 3Pθ)
Abbreviated as 2. ) and 4-ethylbenzoic acid-41-cyanophenyl ester (hereinafter abbreviated as 2"0).

), 4-n-butylbenzoic acid-4'-cyanophenyl ester (hereinafter abbreviated as 4KO), 1.4-n-butylcyclohexanecarboxylic acid-41-ethoxyphenyl ester (hereinafter abbreviated as 4HBθ2), and H4 - x-propylcyclohexanecarboxylic acid-41-ethoxyphenyl ester (hereinafter abbreviated as 3HKθ2) and P-3-
Pentylcyclohexane-p+-cyanobiphenyl (hereinafter abbreviated as 5 HBO) and P-3-ventilur 1-
It is abbreviated as T15 below. ]and]P
-Lupentylcyclohexachitin-P'-B-propylcyclohexane biphenyl (hereinafter abbreviated as 0BO-53) and P-isobenthyl p+cyanobiphenyl (hereinafter OB
It is abbreviated as -15. ) liquid crystal composition.

Example 2 is 0D-3,0D-4,5H]l[iZ.

A liquid crystal composition in which liquid crystals of 7HEZ, 3Pθ2.4HEθ2.3HElθ2, 6-4mo, 5HBO, and T15.0B-15 are mixed.

11 people Lower i Maro - Table 1 shows the composition ratio and liquid crystal temperature range of the mixed liquid crystals listed above.
Then, the above liquid crystal Mi base material was converted into a transmission type liquid crystal cell (cell thickness ~1
0 μ? +1. , 1,000-line alignment process, the twist angle is the answer speed (0
℃ and 25℃) are shown in Table 2.

Table 2〉 (Note 1) Vth and V8cLt are the effective voltages when the transmittance becomes 10% and 901f when no voltage is applied, respectively (Note 2) p value = (■8αt −v t5 /V t
h (Note 3) γ value = (V 50% - V th) /V
As is clear from Tables 1 and 2, the liquid crystal composition of the present invention has a wide liquid crystal temperature range, low temperature dependence, and excellent steepness. Furthermore, in terms of response speed, it exhibits characteristics that are as good as, if not superior to, conventional biphenyl-based products.

Therefore, conventional biphenyl as a liquid crystal for high time division. It can be said that the liquid crystal composition is significantly improved over ester-based liquids.

that's all Applicant: Daini Seiko Co., Ltd.★ Agent: Patent Attorney Mogami 11-

Claims (1)

[Claims] (1) The general formula is R1-g:)-e-ON (
However, R8 represents a straight chain alkyl group having 3 to 5 carbon atoms.)
It contains a total of 10% to 40% of the liquid crystal compound represented by the formula, and represents a linear alkyl group having 3 to 7 carbon atoms. ) contains a total of 10% to 40% of the liquid crystal compound represented by
A liquid crystal composition containing 2 to 20q6 liquid crystal compounds represented by Rs -0-R+ (where RIsR4 represents a straight-chain alkyl group having 2 to 6 carbon atoms) and also contains an optically active substance. 2. The liquid crystal composition according to claim 1, which contains a liquid crystal compound represented by the formula (wherein R6 represents a straight-chain alkyl group having 2 to 6 carbon atoms). However, Ra*R7 represents a straight chain alkyl group having 2 to 4 carbon atoms. ) The liquid crystal composition according to claim 1 or 2, which contains a liquid crystal compound represented by: (4) The general formula is R6-[koON (however,
R8 represents a straight chain alkyl group having 3 to 7 carbon atoms. ] Claim 1, item 2 containing a liquid crystal compound represented by
The liquid crystal composition according to item 1 or 3. (5) Claims 1, 2, or 3
The liquid crystal composition described in . (6) The general formula is RIO-Softhoutei R11 (however, Rl
G represents a straight chain alkyl group having 3 to 5 carbon atoms. ) The liquid crystal composition according to claim 1, 2, 3 or 4, which contains a liquid crystal compound represented by (where -0- represents trans-cyclohexane).