Claims
- 1. A nematic liquid crystal mixture having a positive dielectric anisotropy .DELTA..epsilon. of at least +4 and a birefringence .DELTA..epsilon. of at least 0.13, wherein the mixture comprises one or more components of the formula I: ##STR69## wherein L.sup.1 is F, L.sup.2, Y and Z are each independently of one another H or F, one of Q.sup.1 and Q.sup.2 is 1,4-phenylene, 3-fluoro-1,4-phenylene or 3,5-difluoro-1,4-phenylene and the other of Q.sup.1 or Q.sup.2 is --CH.sub.2 CH.sub.2 --, --CH.sub.2 CH.sub.2 CH.sub.2 CH.sub.2 -- or a single bond, R is alkyl, alkoxy, oxaalkyl, dioxaalkyl, alkenyl, fluoroalkyl or chloroalkyl of 1-10 carbon atoms, r is 0 or 1 and X is F, Cl or a fluorinated and/or chlorinated alkyl, alkenyl or alkoxy group of 1 or 2 carbon atoms.
- 2. Mixture according to claim 1 being essentially free of cyano components.
- 3. The mixture of claim 1, wherein in formula (I) one of Q.sup.1 or Q.sup.2 is --CH.sub.2 CH.sub.2 --.
- 4. The mixture of claim 1, further containing one or more compounds of the formula II ##STR70## wherein R is alkyl, alkoxy or alkenyl of up to 10 carbon atoms,
- A is trans-1,4-cyclohexylene or 1,4-phenylene,
- r is 1,
- X is F, Cl, CF.sub.3, OCF.sub.3 or OCHF.sub.2, and
- L.sup.1, L.sup.2 Y and Z are independently H or F with the proviso that at least one of L.sup.1, L.sup.2, Y and Z is F.
- 5. The mixture of claim 1, further containing one or more compounds selected from the group consisting of compounds of the formulae III to IX: ##STR71## wherein n is 1 to 7 and X is F, Cl, CF.sub.3, OCF.sub.3 or OCHF.sub.2.
- 6. The mixture of claim 1, wherein in the formula (I), X is F, Cl, CF.sub.3, OCF.sub.3 or OCHF.sub.2.
- 7. The mixture of claim 1, wherein in the formula (I), R is alkyl or alkoxy of 1-10 carbon atoms.
- 8. The mixture of claim 1, further containing one or more compounds of the following formula ##STR72## wherein r is 0 or 1 and R.sup.1 is alkyl or alkoxy with 1 to 10 carbon atoms.
- 9. The mixture of claim 1, wherein in the component of formula I, L.sup.2 is H.
- 10. The mixture of claim 1, wherein in the formula (I), one of Q.sup.1 or Q.sup.2 is a single bond.
- 11. Matrix liquid crystal display with high temperature and UV-stability containing
- two plane parallel support plates which together with a frame form a cell of thickness d,
- integrated non-linear elements for switching individual picture elements on the support plates, and
- a nematic liquid crystal mixture which is present in the cell, has a positive dielectric anisotropy and a birefrigence .DELTA.n of at least 0.13, the mixture comprising one or more components of the formula I: ##STR73## wherein L.sup.1 is F, L.sup.2, Y and Z are each independently of one another H or F, one of Q.sup.1 and Q.sup.2 is 1,4-phenylene, 3-fluoro-1,4-phenylene or 3,5-difluoro-1,4-phenylene and the other of Q.sup.1 or Q.sup.2 is --CH.sub.2 CH.sub.2 --, --CH.sub.2 CH.sub.2 CH.sub.2 CH.sub.2 -- or a single bond, R is alkyl, alkoxy, oxaalkyl, dioxaalkyl, alkenyl, fluoroalkyl or chloroalkyl of 1-10 carbon atoms, r is 0 or 1 and X is F, Cl or a fluorinated and/or chlorinated alkyl, alkenyl or alkoxy group of 1 or 2 carbon atoms, the display being operated in the second or a higher transmission minimum of the Gooch-Tarry curve dependent upon the value of d.multidot..DELTA.n, wherein the quotient of the voltage holding ratio HR.sub.20 after 20 hours exposure to UV-light (280-400 nm, 12 mW/cm.sup.2) and HR.sub.0 before exposure to UV-light is more than or equal to 98%.
- 12. Display according to claim 11, wherein the thickness d of the cell is 3 to 10 .mu.m.
- 13. Display according to claim 11, wherein the birefringence .DELTA.n of the nematic liquid crystal mixture is from 0.13 to 0.20.
- 14. Display according to claim 4, wherein the liquid crystal mixture further contains one or more compounds of the formula II ##STR74## wherein R is alkyl, alkoxy or alkenyl of 1 to 10 carbon atoms,
- X is F, Cl, CF.sub.3, OCF.sub.3 or OCHF.sub.2, and
- L.sup.1, L.sup.2 Y and Z are each independently H or F, with the proviso that at least one of L.sup.1, L.sup.2 or Z is F.
- 15. The display according to claim 11 wherein the thickness d of the cell is 3 to 7 .mu.m.
- 16. The display according to claim 11 wherein the birefringence .DELTA.n of the nematic liquid crystal mixture is from 0.13 to 0.18.
- 17. Display according to claim 11 wherein the liquid crystal mixture further contains one or more compounds selected from the group consisting of compounds of the formulae III to IX: ##STR75## wherein n is 1 to 7 and X is F, Cl, CF.sub.3, OCF.sub.3 or OCHF.sub.2.
- 18. The display of claim 11, wherein in the formula (I), X is F, Cl, CF.sub.3, OCF.sub.3 or OCHF.sub.2.
- 19. The display of claim 11 wherein in the formula (I), R is alkyl or alkoxy of 1-10 carbon atoms.
- 20. A display according to claim 11, wherein the liquid crystal mixture further contains one or more compounds of the following formula ##STR76## wherein r is 0 or 1 and R.sup.1 is alkyl or alkoxy with 1 to 10 carbon atoms.
- 21. The display of claim 11, wherein in the formula (I), L.sup.2 is H.
Priority Claims (2)
Number |
Date |
Country |
Kind |
90106252 |
Apr 1990 |
EPX |
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90115501 |
Aug 1990 |
EPX |
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Parent Case Info
This application is a continuation, of application Ser. No. 08/462,525, filed Jun. 5, 1995 now abandoned, which is a continuation of Ser. No. 08/067,154, filed May 26, 1993 pending.
US Referenced Citations (11)
Foreign Referenced Citations (2)
Number |
Date |
Country |
0 272 580 |
Dec 1987 |
EPX |
256636 |
Feb 1988 |
EPX |
Non-Patent Literature Citations (2)
Entry |
R. Dabrowski et al., Liquid Crystals, vol. 5, No. 1, pp. 209-216, 1989. |
V. Reiffenrath et al., SPIE, vol. 1257 Liquid Crystal Displays and Applications (1990) pp. 84-94. |
Continuations (2)
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Number |
Date |
Country |
Parent |
462525 |
Jun 1995 |
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Parent |
067154 |
May 1993 |
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