DD158177A3 - CRYSTALLINE-LIQUID NEMATIVE MIXTURES - Google Patents

Abstract

The invention relates to crystalline-liquid nematic mixtures which are used in optoelectronic devices. The aim of the invention is the use of nematic mixtures for optoelectronic components, which have a high positive dielectric anisotropy at sufficiently high Klaerpunkten. According to the invention, mixtures are used in optoelectronic components which contain, in addition to other crystalline liquid or non-crystalline substances, one or more compounds of the general formula ## STR5 ## where R is a high level of one or more fluoro groups of various types, e.g. Alkyl, alkyloxy; X represents an aromatic, hydroaromatic or heterocyclic ring system, such as e.g. Phenyl or cyclohexyl; Y is a centerpiece such as Carbonyloxy, azomethine, azoxy.

Description

21,841

Crystalline - liquid nematic mixtures

Field of application of the invention . ·; '

The invention "relates to crystalline liquid nematic mixtures which are used in electro-optical arrangements for the modulation of the transmitted or incident light as well as for the reproduction of numbers, characters and images.

Characteristic of the well-known technical solutions

It is known that with the aid of suitable nematic liquid-crystalline substances electro-optical arrangements for modulating the light and for reproducing numerals ₅ characters and images can be produced, in particular nematic liquid crystals with positive dielectric anisotropy allow the production of rotary cells or Cells Based on the Guest-Host Effect / M. Tobias, International Handbook of Liquid Crystal Displays 1975-1'976, Ovum Ltd. London 1976 /.

In order to achieve low threshold and operating voltages, which are very advantageous especially in battery-operated devices, substances with high values of the positive

20-volt dielectric anisotropy. Also of great importance are the melting and clearing points of the substances used, since they define the operating temperature range of the components. Since so far .No pure substances are known, which also have sufficiently low melting points at the required relatively high clearing points, they become exclusive

21841O

In order to be able to adapt the mixtures to the various requirements, corresponding substances are required as components. Therefore, they are always looking for new suitable compounds.

Object of the invention

The object of the invention is the use of crystalline mixtures for electro-optical arrangements, which have a high positive dielectric anisotropy at sufficiently high clearing points.

Explanation of the essence of the invention

It has been found that for use in electro-optical An. Arrangements for the modulation of the continuous or incident light and for the reproduction of numbers, characters and images crystalline-liquid nematic mixtures are suitable, which

Substances of the general formula

where X =

and 20 or

R = C _n H _{2n + 1} ,

X =

Y = -COO-

Y = -COO-, -00C-, -COS-5 -SOC-, -CH = N-, -N = CH-,

i 4

= ^C n ^H 2n-H> ^G n ^H 2n ₊ 1 ^G '

^C n ^H 2n-H ° ^C0 °> ^C n ^H 2

-CH = CH-, -CiC-, -COON = C-

> ^C n ^H 2n-M ^C00 >

C. TI f PU ^ TM

c. xx ~ r ι j - r, UJ., rsr, oJi-z, U ₂ Hk, υϋ ^ υ

with η = 1 to 10, as components of this crystalline

liquid mixtures together with other crystalline-liquid or non-crystalline liquid compounds.

, The mixtures according to the invention are stable and colorless, have high values of positive dielectric anisotropy 5 and high clearing points. . ·

Example 1 . , , ,

The following table shows compounds which are used as components of the mixtures according to the invention, with their melting and clearing points. In this case: 10 K '= crystalline-solid N> nematic

S. = smectic A .....; I isotropic-liquid Values in parentheses indicate monotropic crystalline-liquid Pha-.sen. . ·

1 ii

R-X-CO-

15 No. R

1 C ₆ H 13 2 ' C ₄ H 9 ° 3; C ₅ H 11 ° 4 C ₆ H 13 ° 5 C ₉ H 19 ° 6 C ₄ H ₉ coo 7 , C ₆ H ₁₃ co 8th C ₆ H 13 ° 9 C ₂ H 5 ' 10 C. H'D 13

COO

, 132 - - (

.131 - - C

, 84. 90

.111 - - (.84

, 95.5 .- '- (

, 75 .. 79 (

97) i

89.5).

9.4,5).

96

101):. 102

• 95) ♦

47).

86).

1841

Example 2 '·.

The static dielectric anisotropies Λ £ have the following values: ·

Substance No. 5 AS = + 7 at 363 K (90 ^° C.) Substance No. 7 Af = + -9.5 at 353 K (80 ^° C.)

Example 3.

The components of the mixtures according to the invention are included. However, due to a relaxation process and the consequent failure of the longitudinal components of the dipole moment at higher frequencies, negative dielectric anisotropy (-d ≤ <0) occurs at low frequencies and in the static dielectric region. As a result, these substances are suitable for displays based on the two-frequency method.

The substance No. 7 has the relaxation area at the following frequencies:

Frequency (Mz) Temperature ( ⁰ C)

0.89 81

•. 1.47 89.5

2.2 96

Example 4

, "^ The basic mix" Mi 8 "consists of the following components:

'Mol- ^c h Me-thoxybenzoesäurehexyloxyphenylester · 19.6

Pentyloxybenzoic acid octyloxyphenyl ester 29.5

25'-hexylbenzoic acid butyloxyphenyl ester. 29.5

Butyloxycarbonyloxybenzoic acid hexyloxy-phenyl ester 11,8

2-iithylhyaequinone-bis- [4-n-hexylbenzoate] 9> 5

A mixture of 90 Gew. -Io Mi 8 and 10

has a clearing point of 71.5 ⁰ C. This mixture also shows, after a J / eek no crystallization at -10 ⁰ C. The

Threshold voltage of the dielectric rearrangement in a twist cell is 3.7 volts (layer thickness: 20 yam, frequency: 500 Hz).

Claims (1)

Lt Invention claim 1. Application of crystalline-liquid nematic mixtures, "in which at least one component is a 1,4-disubstituted benzene derivative, for electro-optical arrangements for the modulation of the transmitted or incident light and for playback τοη digits ₅ characters and images characterized in that as such components Substances of the general formula where X = and R ¹ = or X = JT -XY- ^ Qh-CH = C (CN) ₂ Y = -COO- Y = -COO-, -00C-. -N = N-, COO-N = C- -COS, -SOC- ₅ -CH = N-, -K = CH-, -N = N-, -N = N-, 0 0 CH = CH-, ^C n ^H 2n ₊ 1 ' ^C n ^H 2n ₊ -1 ⁰ ' - ^C n ^H 2n ₊ 1 ^S '" ^C n ^H 2n ₊ 1 ^C00 ' ^C n ^H 2n-M ^0C00> - ⁰ F, Cl, Br, CH _3, C with η = Λ to 10, are used. R ² ' , CH- ^ O