LC medium

Abstract

The present invention relates to liquid-crystalline (LC) media and to LC displays (LCDs) containing these media, in particular to LCDs of the twisted nematic (TN) mode, preferably to displays of the LCOS (LC on silicon) mode.

Claims

1. An LCOS display, comprising a silicon-containing backplane (1), a reflective coating (2) in the shape of a pixel array, first (3) and second (4) alignment layers providing planar alignment, a layer (5) of the LC medium, a transparent electrode layer (6), and a transparent substrate (7), and in said LCOS display an LC medium with positive dielectric anisotropy, said medium comprising one or more compounds of formula I, one or more compounds of formulae II or III, and one or more chiral dopants ##STR00381## wherein the individual radicals, independently of each other and on each occurrence identically or differently, have the following meanings alkyl C.sub.1-6-alkyl, R.sup.a1 H, CH.sub.3 or C.sub.2H.sub.5, i, k 0, 1, 2 or 3, ##STR00382## R.sup.0 an unsubstituted or halogenated alkyl or alkoxy radical having 1 to 15 C atoms, where, in addition, one or more CH.sub.2 groups in these radicals may each be replaced, independently of one another, by C?C, CF.sub.2O, CH?CH, ##STR00383## O, COO or OCO in such a way that O atoms are not linked directly to one another, or denotes ##STR00384## X.sup.0 F, Cl, CN, SF.sub.5, SCN, NCS, a C.sub.1-6-halogenated alkyl radical, a C.sub.2-6-halogenated alkenyl radical, a C.sub.1-6-halogenated alkoxy radical or a C.sub.2-6-halogenated alkenyloxy radical, and Y.sup.0 H or CH.sub.3, Y.sup.1-6 H or F, said display having a helical twisting power and an amount of the chiral dopant in the LC medium are selected such that the display has a ratio d/p of 0.015 to 0.2.

2. The LCOS display according to claim 1, wherein the LC medium comprises as one or more chiral dopants R- or S-1011, R- or S-2011, R- or S-3011, R- or S-4011, or R- or S-5011: ##STR00385##

3. The LCOS display according to claim 1, wherein the LC medium comprises one or more compounds of formula I of the following subformulae ##STR00386## wherein alkyl has the meaning given in claim 1.

4. The LCOS display according to claim 1, wherein the LC medium comprises one or more compounds of formula I of the following subformulae: ##STR00387##

5. The LCOS display according to claim 1, wherein the LC medium comprises one or more compounds of formula II of the following subformulae ##STR00388## ##STR00389## in which R.sup.0 and X.sup.0 have the meanings given in claim 1.

6. The LCOS display according to claim 1, wherein the LC medium comprises one or more compounds of formula III of the following subformulae ##STR00390## ##STR00391## ##STR00392## in which R.sup.0 and X.sup.0 have the meanings given in claim 1.

7. The LCOS display according to claim 1, wherein the LC medium comprises one or more compounds of the following formulae ##STR00393## in which R.sup.0, X.sup.0 and Y.sup.1-4 have the meanings given in claim 1, Z.sup.0 denotes C.sub.2H.sub.4, (CH.sub.2).sub.4, CH?CH, CF?CF, C.sub.2F.sub.4, CH.sub.2CF.sub.2, CF.sub.2CH.sub.2, CH.sub.2O, OCH.sub.2, COO or OCF.sub.2, in formulae V and VI also a single bond, in formulae V and VIII also CF.sub.2O, r denotes 0 or 1, and s denotes 0 or 1.

8. The LCOS display according to claim 1, wherein the LC medium comprises one or more compounds of the following formulae ##STR00394## in which R.sup.0 has the meanings given in claim 1.

9. The LCOS display according to claim 1, wherein the LC medium additionally comprises one or more compounds of the following formulae: ##STR00395## in which X.sup.0 has the meanings given in claim 1, and alkyl denotes C.sub.1-6-alkyl, alkenyl and alkenyl* denote independently of each other C.sub.2-6-alkenyl, L denotes H or F, R denotes C.sub.1-6-alkyl, C.sub.1-6-alkoxy or C.sub.2-6-alkenyl.

10. The LCOS display according to claim 1, wherein the LC medium comprises one or more compounds of the formulae: ##STR00396## wherein alkyl denotes C.sub.1-6-alkyl.

11. The LCOS display according to claim 1, wherein the LC medium comprises one or more compounds of the following formula: ##STR00397## in which R.sup.1 and R.sup.2 independently of each other denote alkyl having 1 to 6 C atoms.

12. The LCOS display according to claim 1, wherein the LC medium additionally comprises one or more compounds of the following formulae: ##STR00398## in which R.sup.3 and R.sup.4 each, independently of one another, denote C.sub.1-6-n-alkyl, alkoxy, oxaalkyl, fluoroalkyl or C.sub.2-6-alkenyl.

13. The LCOS display according to claim 1, wherein the LC medium additionally comprises one or more compounds of the following subformulae: ##STR00399## in which alkyl denotes C.sub.1-6-alkyl.

14. The LCOS display according to claim 1, wherein the LC medium comprises one or more compounds of the formula XVI ##STR00400## in which R.sup.3 and R.sup.4 each, independently of one another, denote C.sub.1-6-n-alkyl, alkoxy, oxaalkyl, fluoroalkyl or C.sub.2-6-alkenyl, and L denotes H or F.

15. The LCOS display according to claim 1, wherein the LC medium comprises a compound of formula XVIc2 ##STR00401##

16. The LCOS display according to claim 1, wherein the LC medium comprises one or more compounds of formula IA1 ##STR00402## in which R.sup.0 is ethyl or propyl and X.sup.0 is F.

17. The LCOS display according to claim 1, wherein the LC medium comprises one or more compounds of the following formulae ##STR00403## in which R.sup.0, X.sup.0 and Y.sup.1-4 each, independently of one another, have one of the meanings given in claim 1.

18. The LCOS display according to claim 1, wherein the LC medium comprises one or more compounds of the formula XXIa ##STR00404## in which R.sup.0 denotes ethyl, n-propyl, n-butyl or n-pentyl.

19. The LCOS display according to claim 1, wherein the LC medium comprises one or more compounds of the following formulae ##STR00405## in which R.sup.3 denotes C.sub.1-6-n-alkyl, alkoxy, oxaalkyl, fluoroalkyl or C.sub.2-6-alkenyl, and X.sup.0 has the meaning indicated in claim 1.

20. The LCOS display according to claim 1, wherein the LC medium comprises one or more compounds of the formula XXIXa ##STR00406## in which R.sup.3 denotes ethyl, n-propyl, n-butyl or n-pentyl.

21. The LCOS display according to claim 1, wherein the LC medium comprises one or more stabilizers.

22. The LCOS display according to claim 1, wherein the LC medium comprises one or more stabilizers of the following formulae ##STR00407## wherein the individual radicals, independently of each other and on each occurrence identically or differently, have the following meanings R.sup.a-d C.sub.1-10-straight-chain or C.sub.3-10-branched alkyl, X.sup.S H, CH.sub.3, OH or O.Math., A.sup.S C.sub.1-20-straight-chain, or C.sub.3-20-branched or cyclic alkylene which is optionally substituted, n an integer from 1 to 6.

23. The LCOS display according to claim 1, wherein the LC medium comprises one or more stabilizers of the following formulae ##STR00408## ##STR00409##

24. The LCOS display according to claim 1, wherein the LC medium does not contain compounds having a cyano group.

Description

EXAMPLE 1

(1) The LC mixture N1 is formulated as follows:

(2) TABLE-US-00007 APUQU-3-F 9.0% cl.p. 92.6? C. CC-3-V 15.0% ?n 0.1454 CC-3-V1 8.0% ?? + 11.3 CCH-35 7.5% ?.sub.|| 14.8 CPGP-5-2 6.0% ?.sub.1 119 mPa.Math.s CPGP-5-3 5.0% K.sub.1 15.3 CPP-3-F 8.0% K.sub.3 14.9 PCH-301 4.5% V.sub.0 1.23 V PGP-2-3 8.0% PGUQU-3-F 9.5% PP-1-2V1 2.5% PPGU-3-F 0.5% PUQU-3-F 16.5%

(3) To 99.28% of the mixture N1 are added 0.72% of the chiral dopant S-4011.

EXAMPLE 2

(4) The LC mixture N2 is formulated as follows:

(5) TABLE-US-00008 APUQU-2-F 6.0% cl.p. 92.8? C. APUQU-3-F 6.0% ?n 0.1119 BCH-32 4.5% ?? 11.5 CC-3-V 33.5% ?.sub.|| 15.0 CC-3-V1 1.0% ?.sub.1 96 mPa.Math.s CCP-V-1 10.0% K.sub.1 13.4 CCP-V2-1 10.0% K.sub.3 16.5 CDUQU-3-F 6.0% V.sub.0 1.14V CPGP-5-2 2.5% PGUQU-3-F 4.0% PGUQU-4-F 4.0% PPGU-3-F 0.5% PUQU-3-F 12.0%

(6) To 99.75% of the mixture N2 are added 0.22% of the chiral dopant S-4011 and 0.03% of the stabiliser S1-1.

(7) ##STR00379##

EXAMPLE 3

(8) The LC mixture N3 is formulated as follows:

(9) TABLE-US-00009 APUQU-2-F 6.0% cl.p. 92.8? C. APUQU-3-F 6.0% ?n 0.1119 BCH-32 4.5% ?? 11.5 CC-3-V 33.5% ?.sub.|| 15.0 CC-3-V1 1.0% ?.sub.1 96 mPa.Math.s CCP-V-1 10.0% K.sub.1 13.4 CCP-V2-1 10.0% K.sub.3 16.5 CDUQU-3-F 6.0% V.sub.0 1.14 V CPGP-5-2 2.5% PGUQU-3-F 4.0% PGUQU-4-F 4.0% PPGU-3-F 0.5% PUQU-3-F 12.0%

(10) To 99.888% of the mixture N3 are added 0.04% of the stabiliser S2-1 and 0.108% of the chiral dopant S-4011.

(11) ##STR00380##