JPS61278589A - Liquid crystal composition - Google Patents

Abstract

PURPOSE:To obtain a liq. crystal compsn. which is high in response rate, low in cross frequency, fc, high in absolute value of dielectric anisotropy, epsilon, in both low-and high-frequency regions and excellent in low-temp. resistance, by incorporating at least eight specific kinds of compds. CONSTITUTION:At least one compd. selected from among those of the formulae I-VIII (wherein R1, R6-R8, R1'-R2' and R6' are each a 1-10C straight-chain alkyl; R2-R5 and R3'-R5' are each a 1-8C straight-chain alkyl) and mixed with each other. The amount of each compd. of 10-60% (by weight; the same shall apply hereinafter) in the case of the compd. of the formula I, 1-40% in the case of the compd. of the formula II, 1-30% in the case of the compd. of the formula III, 1-25% in the case of the compd. of the formula IV, 1-15% in the case of the compd. of the formula V, 1-15% in the case of the compd. of the formula VI, 1-25% in the case of the compd. of the formula VII, 1-20% in the case of the compd. of the formula VIII. If necessary, 1-10% compd. of the formula IX wherein R9 is R2) and/or 1-10% compd. of the formula X (wherein R10 and R2) are added thereto.

Description

DETAILED DESCRIPTION OF THE INVENTION [Description of the field to which the invention pertains] The present invention relates to a liquid crystal composition for dual-frequency driving method.

Liquid crystals have induced anisotropy Δε (hereinafter referred to as Δε).
is expressed as the difference ε11−ε1 between the dielectric constant ε1 in the direction parallel to the long axis of the molecule and the dielectric constant ξ1 in the direction perpendicular to the long axis of the molecule.

Furthermore, liquid crystal molecules are rod-shaped, and when the frequency of the alternating current voltage exceeds a certain frequency, the alignment in the long axis direction cannot be followed, causing dielectric dispersion. In other words, in Figure 1, Δε=ε1
There is a frequency equal to 1"-'J"', and that frequency is called the cross frequency fc.A dual-frequency drive method liquid crystal display! ! [1] Since the liquid crystal reverses the sign of ΔC at this fc'e boundary, this is used to raise and lower the frequency (108Hg → lQ"Hg), thereby changing the orientation of the liquid crystal molecules. For this reason, the liquid crystal assembly The phase object has the following characteristics: l) The crossover frequency fa is low.

2) The absolute value of ΔgQ in the low frequency region (medium 1n'') 1g) and high frequency region (108Kg) is large.

3) Low viscosity.

4) The temperature dependence of fc is small.

5) Wide liquid crystal temperature range.

is required.

[Description of prior art]

The conventional liquid crystal for dual-frequency driving method has a problem in that Δε, especially ε in the low frequency region (KITO''IIIg), is small, and FLf: If an attempt is made to solve this problem, the cross frequency fc becomes high.9.

[Purpose of the invention]

An object of the present invention is to eliminate such drawbacks and provide a liquid crystal composition having a large Δε especially in the low frequency region (*10''Hz).

Another object of the present invention is to provide a liquid crystal composition with a low crossover frequency fc.

Another object of the present invention is to provide a liquid crystal composition that is resistant to precipitation at low temperatures.

Another object of the present invention is to provide a liquid crystal composition with a fast response speed.

Another object of the present invention is to provide a liquid crystal composition with low temperature dependence.

[Departure qo special request/means]

The present invention is based on the above object and provides a liquid crystal composition that satisfies the above conditions.

A liquid crystal composition containing at least one component of each group 0) to (8) represented by the general formula % (1).

however.

R1 is a straight chain alkyl group having 1 to 10 carbon atoms.

RI I 1~xll pR biased
I 1~81 R% y l~11) #R, #1~
8 〃 R', #1~8N R4〃 1~8 〃 R-〃 1~8 lR5#
1~8N R', x 1~8I R, #1~10 1 R1,, #1~10
The above object is achieved by a liquid crystal composition which contains compounds of each group ω~(8) represented by 1R7yl~1OI R, #l~lOl.

[Embodiments of the invention]

Table 1 shows specific examples of liquid crystal compositions of the present invention.

Specific examples of compound ω are A, B jC, specific examples 7fCF' to G of compound (2), and specific examples of compound (3) are R to
Specifically, a specific example of compound (4) is given as T, KIC, compound (
A specific example of 5) is L~”K h compound (6) (D
Specific example of full is 0~PVC1 compound (7) is Q-
TK, specific examples of compound (8) are U to W, compound (9)
A specific example of compound 110 is shown as XVc, and a specific example of compound 110 is shown as Y.

The liquid crystal composition of the present invention is based on compound (1). The compound ω has a low crossing frequency j′G, low viscosity, low temperature dependence, and a wide liquid crystal temperature range. Compound (1) is mixed in the liquid crystal composition of the present invention in an amount of 1( Therefore, the liquid crystal composition of the present invention can be operated at low voltage, over a wide operating temperature range, and has fast response speed.

Compound (2) is particularly effective in preventing precipitation at low temperatures, but
Since there is a tendency to increase fct, there is a limit to the amount of compound (2) to be mixed, and in the liquid crystal composition of the present invention, compound (2) was adjusted within 1 to 40% by weight.

Compounds (3) and (4) have a low fa and a wide temperature range, but if used in large quantities, the supercooling effect of the liquid crystal composition of the present invention will be lost. Hypoallergenic (3
) and (4) were adjusted within FL1-30.1-25, respectively.

18 compounds (5) and (6) have a large ε1 and a large negative value of ΔC. In addition, by mixing 1 to 15% by weight of each of the liquid crystal compositions of the present invention with low h f c, the absolute value of Δε in the driving high frequency region can be increased, and f
(Bring out the effect of lowering k.

Compounds (7) and (8) have large gll and Δε
takes a large positive value. Since compound (7) tends to increase fc when used in large amounts, it is adjusted within 1-25% by weight in the liquid crystal composition of the present invention. Moreover, compound (8) is f
Although it has the effect of lowering c, if a large amount is used, precipitation will occur at low temperatures, so in the liquid crystal composition of the present invention, it is mixed at a weight of 1 to 1.

The compound represented by formula (9) (Rainbow) has a large ε11 and Δ
Compound (9), Q□, which exhibits a large positive value, tends to increase fc and cause precipitation at low temperatures when used in large quantities, so it is not suitable for use in the liquid crystal composition of the present invention.
L was adjusted within 1 to 10% by weight.

Fermentation Table 2 Table 2 shows the liquid crystal composition of the present invention produced using the above-mentioned compounds (1) to ir>. Liquid crystal compositions 1.2 produced by mixing compounds (1) to 11O all have large ΔC values of 6.0 or more at 40° C. in the low frequency region.

Also, fc is low, below 4Q u, II. Furthermore, the response speed is within 0.4 msec at startup.
Fast fall time (within 0.3ms e c), and low temperature resistance of 1
5!3 or more, which is good.

There are some differences between Examples 1 and 2.

Example 1 is ε! Compound (9) is used as one of the compounds that has the effect of increasing l, and Δe in the low frequency region is 7.
．． It takes a large value of 4. This also increases the response speed, especially the falling speed.

Example 2 uses Compound 10 as one of the compounds having the effect of increasing ε11. FLFi compound (9)
Since the effect of increasing ε11 is slightly weaker, implementation 1P!
In I2, the value of Δε in the low frequency region is slightly smaller than that in the first embodiment. As a result, the falling speed is also slightly delayed.

As described above, the liquid crystal composition for the dual-frequency drive method of the present invention has the advantages of fast response speed, good low temperature resistance, low crossover frequency fc, and a large absolute value of Δε in the low Φ high frequency region. It is something that has.

As an application of the present invention, a liquid crystal display device using the liquid crystal for dual-frequency driving method of the present invention is free from precipitation even at a temperature of 1°C and has a fast response speed of within 0.4 msec. Used for required display devices for measuring instruments.

As another application, it can be used in the head of a printer equipped with a backlight and capable of printing at high speed by exposing it to light using a shutter effect.

[Brief explanation of drawings]

FIG. 1 shows the dielectric constant e11. In Figure 1, which is a diagram showing the relationship between ε and frequency f, Δε is expressed as ε11−ε1. Further, fc is a frequency at which all-ε1=O. that's all

Claims (1)

[Claims] 1) General formula R_1-■-COO-■-OR' (1) R_2-O-■-COO-■-R'_2 (2) R_3-
■−■−COO−■−R′_3(3)▲Mathematical formula, chemical formula,
There are tables, etc. ▼ (4) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (5) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (6) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (7) ▲ Mathematical formulas, There are chemical formulas, tables, etc. ▼ (8) A liquid crystal composition characterized by containing at least one component of each group (1) to (8) represented by the following. However, R_1 is a straight chain alkyl group having 1 to 10 carbon atoms. R'_1 〃 1-10 〃 R_2 〃 1-8 〃 R'_2 〃 1-10 〃 R_3 〃 1-8 〃 R'_3 〃 1-8 〃 R_4 〃 1-8 〃 R'_4 〃 1-8 〃 R_5 〃 1-8 〃 R'_5 〃 1-8 〃 R_6 〃 1-10 〃 R'_6 〃 1-10 〃 R_7 〃 1-10 〃 R_8 〃 1-10 〃 2) The ratio of compound (1) is 10 ~60% by weight. 〃 (2) 〃 1-40〃 〃 (3) 〃 1-30〃 〃 (4) 〃 1-25〃 〃 (5) 〃 1-15〃 〃 (6) 〃 1-15〃 〃 (7) 〃 1-25〃〃(8)〃1-20〃 The liquid crystal composition according to claim 1. 3) Contains at least one component of the compounds (9) and (10) represented by the general formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (9) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (10) The liquid crystal composition according to claim 2, characterized in that: However, R_9 is a straight chain alkyl group having 1 to 8 carbon atoms. R_1_0 〃 1-8 〃 4) The proportion of compound (9) is 1-10% by weight. (10) The liquid crystal composition according to claim 3, wherein the liquid crystal composition is from 1 to 10.