DD155078B5 - Application of crystalline-liquid substances - Google Patents

Description

OR

where R = -H, - @ - R, ~O " ^C ni ^H 2m + 1 R ¹ = -c _m H _2m ., .- о

-F, -Cl, -Br, -CN, -CF ₃ , -NO ₂ -C ₂ H ₄ CN

in which m and η can be identical or different and are 1 to 10, alone, in mixtures with one another and / or in mixtures with other crystalline liquid or non-crystalline liquid compounds, in particular dyes, in optoelectronic components for modulation of the conspicuous or continuous Light as well as for the representation of numbers, signs and pictures are very well applicable. The substances according to the invention can be prepared by reproducible processes in good purity and high yield. They are colorless, stable to light, heat, water and electric fields.

embodiments example 1

The following table shows the transformation temperatures of substances according to the invention.

_n H _{2n + 1} - Q-CH ₂ -CH ₂ -COOr

η R K N is

5 H 53 · 103

5 - @ - CN 47 79

K = crystalline-solid N = nematic is = isotropic-liquid

Example 2

trans-3- [4-n-pentylcyclohexyl] -propanoic acid 4'-cyanophenyl ester is placed in a twisted nematic layer electro-optic cell. The cell consists of two transparent electrodes which have been rendered anisotropic by defined rubbing or oblique evaporation and have an orienting effect on the liquid crystal. By twisting the preferred directions of the two electrodes relative to each other by 90 °, the twisted nematic layer (Schadt-Helfrich cell) is formed, which is observed between crossed polarizers.

The substance, the thermodynamically stable melting point is 47 ⁰ C, can be easily supercooled without crystallization to room temperature. At 20 ^° C., the cell exhibits the following properties:

Threshold voltage 1.2 volts / 50 Hz

Onset time (50% intensity change): 100 ms at 4 V

Cooldown (50% intensity change): 100 ms

Layer thickness: 10 μηι

Both the low threshold voltage and the time behavior proved the favorable properties of the substances according to the invention.

Example 3

To trans-3- [4-n-pentyl-cyclohexyl] -propanoic acid 4'-cyanphenylester 1 wt .-% of a red dichroic dye (substance formula: NO ₂ - (ζ ^) -N = N- @) '^ ^ ru Vu nu 'mixed. Between two transparent, electrically conductive

Glass panes was prepared a planar oriented layer in which the preferred direction of the longitudinal molecular axes is uniformly oriented parallel to the glass surfaces. The uniform orientation was achieved by the use of obliquely evaporated glasses (evaporation angle 60 °). When irradiated with white polarized light, this layer is strongly colored red, if the direction of vibration of the light coincides with the preferred direction of the planar layer. After applying an electrical voltage that is greater than the threshold voltage, an envelope turns red -► colorless due to the dielectric reorientation of the nematic layer. Properties of the cell at 20 ° C:

Threshold voltage 1.3VoIt

Settling time (50% intensity change): 300 ms at 5 volts

Cooldown (50% intensity change): 150 ms

Layer thickness: 10 μ, νη

Example 4

It was an equimolar mixture of

C ₅ H ₁₁ - (И) -CH ₂ CH ₂ COO- -CN

and C ₄ H ₉ - (Π) -COO- -OC ₂ H ₅ (K 36 N 75.5 is)

manufactured.

The mixture melts at 25 ⁰ C and is at 75 ⁰ C in the isotropic state.

The threshold voltage of a Twistzelle is at 25 ⁰ C 1.5 volts.

Claims (1)

Use of novel crystalline liquid substances for optoelectronic components for modulation of the incident or transmitted light and for the display of numbers, characters and images, characterized in that trans-3- [4-alkyl-cyclohexyl] -propanoic acids and their esters of the general formula OR where R = -H, - © -H ¹ , -O " ^C m ^H 2m + 1 _{+ v} -co c _m H _{2m + v} -OCOC _1n H _{2111 +} V-OCOOC _1n H _{21n + 1} ,
-F, -Cl, -Br, -CN, -CF ₃ , -NO ₂
-C ₂ H ₄ CN in which m and η may be identical or different and are 1 to 10, alone, in mixtures with one another and / or in mixtures with other crystalline liquid or non-crystalline compounds, in particular dyes used. Field of application of the invention The invention relates to the use of novel crystalline liquid nematic substances in optoelectronic components for modulation of the incident or transmitted light and for the display of numerals, characters and images. Such components can be used in electronic clocks, computers, voltmeters and other devices for display. Characteristic of the known technical solutions There are already a large number of crystalline-liquid compounds known (D. Demus, H. Demus, H. Zaschke: liquid crystals in tables, VEB German publishing house for basic industry Leipzig 1974). Many crystalline substances and mixtures have already been proposed for use in optoelectronic components (D.Demus in: "Nonemissive Electrooptic Displays", Ed., By RA Kmetz and FK v. Willisen, Plenum Press, New York-London 1976, pp. 83-117, VV Titov, Proceed. 3 ^rd Liquid Crystal Conference of Soc. Countries, Budapest 1979; G. Weber, P. del Pino, L. Pohl: Proceed. "10th Freiburger Workshop Liquid Crystals" 1980). There is no connection that meets all the required properties for this purpose. Therefore, substances with special properties are still sought. So far, mixtures of several chemical compounds must always be used. In order to be able to modify their properties, it is necessary to use as many substances of different classes as possible in order to have enough scope for changing the properties. Object of the invention The aim of the invention are stable nematic substances with low melting and sufficiently high clearing temperatures for use in electro-optical components. Explanation of the essence of the invention The object of the invention is to find new crystalline liquid substances. It has been found that novel crystalline liquid trans-3- [4-alkyl-cyclohexyl] -propanoic acids and their esters of the general formula