Liquid crystal medium and electrooptical display containing same

Abstract

The present invention relates to nematic liquid-crystal media of negative dielectric anisotropy which have a peak time (t.sub.max.) of 0.25 ms or less, which is determined as described in the disclosure, and which preferably have a value of the quotient of the peak time and the square of the birefringence (t.sub.max/n.sup.2) of 22 ms or less, and to the use of these liquid-crystal media in liquid-crystal displays, and to these liquid-crystal displays.

Claims

1. A nematic liquid-crystal medium of negative dielectric anisotropy, having a peak time (t.sub.max) of 0.25 ms or less, which is determined with the aid of equations (1) and (2), $\begin{array}{cc}& \mathrm{Equation}\left(1\right)\\ I_{\left({}_0\right)}=\frac{\begin{array}{c}S\left(2{}_1{\sin }^2{}_b{\cos }^2{}_b-{}_2\cos 2{}_b+{}_3\right)\\ {\left({\mathrm{.Math.}}_0\mathrm{.Math.}\sin 2b\right)}^2{E}_b^3\end{array}}{\left({}_1{}_1+{}_2^2\right){\sin }^{2}2{}_b-{}_1^2-{}_2^2+2{}_1{}_3}& \\ & \mathrm{Equation}\left(2\right)\\ t\left({}_b\right)=\frac{{}_2}{2{\mathrm{.Math.}}_0\mathrm{.Math.}{E}_b^2{}_3}\left\{-\ln \left(\frac{\tan {}_b}{\tan {}_0}\right)+\frac{-{}_5+{}_2\sqrt{{}_1}}{2{}_4\sqrt{{}_1}}\ln \left(\frac{{}_4{\tan }^2{}_b+{}_7+\sqrt{{}_1}}{{}_4{\tan }^2{}_0+{}_7+\sqrt{{}_1}}\right)+\frac{{}_5+{}_2\sqrt{{}_1}}{2{}_4\sqrt{{}_1}}\ln \left(\frac{{}_4{\tan }^2{}_b+{}_7-\sqrt{{}_1}}{{}_4{\tan }^2{}_0+{}_7-\sqrt{{}_1}}\right)\right\}+\frac{{}_6}{2{\mathrm{.Math.}}_0\mathrm{.Math.}{E}_b^2\sqrt{{}_1}}\ln \left[\frac{\left({}_1\cos 2{}_b+{}_2+\sqrt{{}_1}\right)\left({}_1\cos 2{}_0+{}_2-\sqrt{{}_1}\right)}{\left({}_1\cos 2{}_b+{}_2-\sqrt{{}_1}\right)\left({}_1\cos 2{}_0+{}_2+\sqrt{{}_1}\right)}\right]& \end{array}$ where: S=electrode area E.sub.b=U/l (U=90 V and l=22 m are assumed), .sub.0=bulk tilt angle at time t=0 .sub.b=bulk tilt angle .sub.1 to .sub.5=Leslie viscosity coefficients,
.sub.1=.sub.1.sup.2+.sub.2.sup.2+2.sub.1.sub.3,
.sub.2=.sub.1.sup.2+.sub.2.sup.22.sub.1.sub.3,
.sub.3=.sub.2.sub.3
.sub.4=.sub.2+.sub.3,
.sub.5=.sub.2.sup.2+.sub.1.sub.3,
.sub.6=.sub.1.sub.1+.sub.2.sup.2,
.sub.7=.sub.1+.sub.3
.sub.1=.sub.2;(rotational viscosity),
.sub.2=.sub.3.sub.2 and
.sub.3=.sub.3+.sub.4+.sub.5, wherein for the Leslie viscosity coefficients, the following assumptions apply
.sub.1=10 mPas and
.sub.3=0 mPas, in addition, for .sub.3=0 in accordance with Parodi:
.sub.4+.sub.5=.sub.2+2.sub.2
.sub.2* where: =density (about 1 g/cm.sup.3) and =flow viscosity, wherein the medium comprises 98% or more of components A and B, and the medium comprises 60-70% of components A, component A is a dielectrically negative, liquid-crystalline component, which consists of: 33% to 37%, based on the medium, of at least one compound of formula I-1 ##STR00119## and 3% to 17%, based on the medium, of at least one compound of formula I-3 ##STR00120## in which R.sup.11 is C.sub.3-7-alkyl, R.sup.11 is C.sub.1-7-alkyl, R.sup.12 is alkyl having 1 to 7 C atoms, alkoxy having 1 to 7 C atoms, alkenyl or alkenyloxy having 2 to 7 C atoms, where in R.sup.11 and R.sup.12 one or more H atoms in all groups may be replaced by halogen atoms, wherein in at least one compound of formula I-1 R.sup.12 is C.sub.4-alkoxy, and the remainder of component A is of one or more dielectrically negative compound(s) of formula I, which are not compounds of formula I-1 or I-3, ##STR00121## in which at least one of ##STR00122## to ##STR00123## denotes ##STR00124## and the others, if present, in each case, independently of one another, have the same meaning or denote ##STR00125## R.sup.11 and R.sup.12, independently of one another, denote alkyl having 1 to 7 C atoms, L.sup.11 and L.sup.12, independently of one another, denote CF or N, Z.sup.11 and Z.sup.12, in each case independently of one another, denote CH.sub.2CH.sub.2, CC, CHCH, CFCF, CFCH, CHCF, CH.sub.2CF.sub.2, CF.sub.2CH.sub.2, CF.sub.2CF.sub.2, COO, OCO, OCH.sub.2, CH.sub.2O, OCF.sub.2, CF.sub.2O or a single bond, and n denotes 0, 1 or 2, and component B is a dielectrically neutral, liquid-crystalline component, which consists of one or more dielectrically neutral compound(s) of formula II ##STR00126## in which R.sup.21 and R.sup.22, in each case independently of one another, are C.sub.1-7-alkyl, C.sub.1-7-alkoxy, or alkoxyalkyl, alkenyl or alkenyloxy having 2-7 cations in which one or more H atoms in all groups may be replaced by halogen atoms, Z.sup.21 to Z.sup.23, in each case independently of one another, are CH.sub.2CH.sub.2, CC, CHCH, COO or a single bond, and ##STR00127## in each case independently of one another, denote ##STR00128## and p and q, in each case independently of one another, denote 0 or 1.

2. The liquid-crystal medium according to claim 1, having a value of the quotient of peak time and square of birefringence (t.sub.max/n.sup.2) of 22 ms or less.

3. The liquid-crystal medium according to claim 1, having an average of the dielectric constants in the range from 5.5 or more to 6.5 or less.

4. The liquid-crystal medium according to claim 1, having a dielectric anisotropy in the range from 3.0 or less to 4.0 or more.

5. The liquid-crystal medium according to claim 1, having a birefringence in the range from 0.070 to 0.110.

6. An electro-optical display containing a liquid-crystal medium according to claim 1.

7. A display according to claim 6, comprising a device for addressing the display having an active matrix.

8. A method for optimizing of the response time of a liquid-crystal display, comprising using in said display a liquid-crystal medium according to claim 1.

9. The display according to claim 7, wherein the device is a matrix of thin-film transistors.

10. The liquid crystalline medium according to claim 1, comprising 30% to 37% of at least one compound of formula II that is of formula II-1 or II-4 ##STR00129## in which R.sup.21 and R.sup.22, in each case independently of one another, denote alkyl having 1 to 7 C atoms, alkoxy having 1 to 7C atoms, alkenyl or alkenyloxy having 2 to 7 C atoms, where one or more H atoms in all groups may be replaced by halogen atoms.

11. The liquid crystalline medium according to claim 1, wherein R.sup.11 is C.sub.1-3-alkyl.

12. The liquid crystalline medium according to claim 1, wherein R.sup.11 is C.sub.2-3-alkyl.

13. The liquid crystalline medium according to claim 1, wherein R.sup.11 is C.sub.3-7-alkyl.

14. The liquid crystalline medium according to claim 1, wherein I-3 is ##STR00130## and n and m are 2.

15. The liquid crystalline medium according to claim 1, wherein I-3 is ##STR00131## and n is 3 and m is 2.

16. The liquid crystalline medium according to claim 1, wherein the compounds of Formula I are compounds of one or more of Formulae I-2, I-4 or I-5 ##STR00132##

17. The liquid crystalline according to claim 1, wherein the medium comprises 99% to 100% of components A and B.

18. The liquid crystalline medium according to claim 1, wherein the concentration of the compounds of formula I-3 is 10% or more.

19. The liquid crystalline medium according to claim 1, wherein the concentration of the compounds of formula I-3 is 13% or more.

20. The liquid crystalline medium according to claim 1, wherein the concentration of component A is 65-69%.

21. The liquid crystalline medium according to claim 1, wherein one or more compounds of formula I are of formula I-2 ##STR00133## wherein R.sup.11 and R.sup.12, independently of one another, denote alkyl having 1 to 7 C atoms, which compounds of formula I-2 have a concentration of 20-30%, based on the medium.

22. The liquid crystalline medium according to claim 1, wherein Z.sup.21 and Z.sup.23 are each independently CH.sub.2CH.sub.2 or a single bond.

23. The liquid crystalline medium according to claim 1, wherein Z.sup.21 and Z.sup.23 are single bonds.

24. The liquid crystalline medium according to claim 1, wherein the one or more compounds of Formula II are of one or more of the following formulae ##STR00134## in which Y.sup.1 is H or F, and R.sup.21 and R.sup.22 are defined as for the compounds of formula II.

25. The liquid crystalline medium according to claim 21, wherein the concentration of the compounds of formula I-2 is 21% to 25%.

26. The liquid-crystalline medium according to claim 1, wherein the one or more compounds of Formula II contain or are a compound of the formula CC-3-V: ##STR00135##

27. The liquid-crystalline medium according to claim 1, wherein component A contains 34% to 37% of at least one compound of formula I-1.

28. The liquid-crystalline medium according to claim 1, wherein component A contains at least two compounds of formula I-1 in which R.sup.12 is C.sub.4-alkoxy.

29. The liquid-crystalline medium according to claim 1, containing three or more compounds of formula I-1.

30. The liquid-crystalline medium according to claim 1, containing four or more compounds of formula I-1.

31. The liquid-crystalline medium according to claim 1, wherein the compounds of formula I-3 contain at least one compound of I-3 in which R.sup.11 is C.sub.3-5 alkyl.

32. The liquid-crystalline medium according to claim 1, wherein Z.sup.21 to Z.sup.23 are a single bond.

33. The liquid crystalline medium according to claim 2, wherein the compounds of Formula I are compounds of one or more of Formulae I-2, I-4 or I-5 ##STR00136##

34. The liquid crystalline medium according to claim 3, wherein the compounds of Formula I are compounds of one or more of Formulae I-2, I-4 or I-5 ##STR00137##

35. The liquid crystalline medium according to claim 4, wherein the compounds of Formula I are compounds of one or more of Formulae I-2, I-4 or I-5 ##STR00138##

36. The liquid crystalline medium according to claim 5, wherein the compounds of Formula I are compounds of one or more of Formulae I-2, I-4 or I-5 ##STR00139##

37. The liquid crystalline medium according to claim 10, wherein the compounds of Formula I are compounds of one or more of Formulae I-2, I-4 or I-5 ##STR00140##

38. The liquid crystalline medium according to claim 11, wherein the compounds of Formula I are compounds of one or more of Formulae I-2, I-4 or I-5 ##STR00141##

39. The liquid crystalline medium according to claim 12, wherein the compounds of Formula I are compounds of one or more of Formulae I-2, I-4 or I-5 ##STR00142##

40. The liquid crystalline medium according to claim 13, wherein the compounds of Formula I are compounds of one or more of Formulae I-2, I-4 or I-5 ##STR00143##

41. The liquid crystalline medium according to claim 14, wherein the compounds of Formula I are compounds of one or more of Formulae I-2, I-4 or I-5 ##STR00144##

42. The liquid crystalline medium according to claim 15, wherein the compounds of Formula I are compounds of one or more of Formulae I-2, I-4 or I-5 ##STR00145##

43. The liquid crystalline medium according to claim 2, wherein one or more compounds of formula I are of formula I-2 ##STR00146## wherein R.sup.11 and R.sup.12, independently of one another, denote alkyl having 1 to 7 C atoms, which compounds of formula I-2 have a concentration of 20-30%, based on the medium.

44. The liquid crystalline medium according to claim 3, wherein one or more compounds of formula I are of formula I-2 ##STR00147## wherein R.sup.11 and R.sup.12, independently of one another, denote alkyl having 1 to 7 C atoms, which compounds of formula I-2 have a concentration of 20-30%, based on the medium.

45. The liquid crystalline medium according to claim 4, wherein one or more compounds of formula I are of formula I-2 ##STR00148## wherein R.sup.11 and R.sup.12, independently of one another, denote alkyl having 1 to 7 C atoms, which compounds of formula I-2 have a concentration of 20-30%, based on the medium.

46. The liquid crystalline medium according to claim 5, wherein one or more compounds of formula I are of formula I-2 ##STR00149## wherein R.sup.11 and R.sup.12, independently of one another, denote alkyl having 1 to 7 C atoms, which compounds of formula I-2 have a concentration of 20-30%, based on the medium.

47. The liquid crystalline medium according to claim 10, wherein one or more compounds of formula I are of formula I-2 ##STR00150## wherein R.sup.11 and R.sup.12, independently of one another, denote alkyl having 1 to 7 C atoms, which compounds of formula I-2 have a concentration of 20-30%, based on the medium.

48. The liquid crystalline medium according to claim 11, wherein one or more compounds of formula I are of formula I-2 ##STR00151## wherein R.sup.11 and R.sup.12, independently of one another, denote alkyl having 1 to 7 C atoms, which compounds of formula I-2 have a concentration of 20-30%, based on the medium.

49. The liquid crystalline medium according to claim 12, wherein one or more compounds of formula I are of formula I-2 ##STR00152## wherein R.sup.11 and R.sup.12, independently of one another, denote alkyl having 1 to 7 C atoms, which compounds of formula I-2 have a concentration of 20-30%, based on the medium.

50. The liquid crystalline medium according to claim 13, wherein one or more compounds of formula I are of formula I-2 ##STR00153## wherein R.sup.11 and R.sup.12, independently of one another, denote alkyl having 1 to 7 C atoms, which compounds of formula I-2 have a concentration of 20-30%, based on the medium.

51. The liquid crystalline medium according to claim 14, wherein one or more compounds of formula I are of formula I-2 ##STR00154## wherein R.sup.11 and R.sup.12, independently of one another, denote alkyl having 1 to 7 C atoms, which compounds of formula I-2 have a concentration of 20-30%, based on the medium.

52. The liquid crystalline medium according to claim 15, wherein one or more compounds of formula I are of formula I-2 ##STR00155## wherein R.sup.11 and R.sup.12, independently of one another, denote alkyl having 1 to 7 C atoms, which compounds of formula I-2 have a concentration of 20-30%, based on the medium.

53. The liquid crystalline medium according to claim 17, wherein one or more compounds of formula I are of formula I-2 ##STR00156## wherein R.sup.11 and R.sup.12, independently of one another, denote alkyl having 1 to 7 C atoms, which compounds of formula I-2 have a concentration of 20-30%, based on the medium.

54. The liquid crystalline medium according to claim 18, wherein one or more compounds of formula I are of formula I-2 ##STR00157## wherein R.sup.11 and R.sup.12, independently of one another, denote alkyl having 1 to 7 C atoms, which compounds of formula I-2 have a concentration of 20-30%, based on the medium.

55. The liquid crystalline medium according to claim 19, wherein one or more compounds of formula I are of formula I-2 ##STR00158## wherein R.sup.11 and R.sup.12, independently of one another, denote alkyl having 1 to 7 C atoms, which compounds of formula I-2 have a concentration of 20-30%, based on the medium.

56. The liquid crystalline medium according to claim 20, wherein one or more compounds of formula I are of formula I-2 ##STR00159## wherein R.sup.11 and R.sup.12, independently of one another, denote alkyl having 1 to 7 C atoms, which compounds of formula I-2 have a concentration of 20-30%, based on the medium.

57. The liquid crystalline medium according to claim 2, wherein the one or more compounds of Formula II are of one or more of the following formulae ##STR00160## ##STR00161## in which Y.sup.1 is H or F, and R.sup.21 and R.sup.22 are defined as for the compounds of formula II.

58. The liquid crystalline medium according to claim 3, wherein the one or more compounds of Formula II are of one or more of the following formulae ##STR00162## in which Y.sup.1 is H or F, and R.sup.21 and R.sup.22 are defined as for the compounds of formula II.

59. The liquid crystalline medium according to claim 4, wherein the one or more compounds of Formula II are of one or more of the following formulae ##STR00163## in which Y.sup.1 is H or F, and R.sup.21 and R.sup.22 are defined as for the compounds of formula II.

60. The liquid crystalline medium according to claim 5, wherein the one or more compounds of Formula II are of one or more of the following formulae ##STR00164## in which Y.sup.1 is H or F, and R.sup.21 and R.sup.22 are defined as for the compounds of formula II.

61. The liquid crystalline medium according to claim 10, wherein the one or more compounds of Formula II are of one or more of the following formulae ##STR00165## in which Y.sup.1 is H or F, and R.sup.21 and R.sup.22 are defined as for the compounds of formula II.

62. The liquid crystalline medium according to claim 11, wherein the one or more compounds of Formula II are of one or more of the following formulae ##STR00166## in which Y.sup.1 is H or F, and R.sup.21 and R.sup.22 are defined as for the compounds of formula II.

63. The liquid crystalline medium according to claim 12, wherein the one or more compounds of Formula II are of one or more of the following formulae ##STR00167## in which Y.sup.1 is H or F, and R.sup.21 and R.sup.22 are defined as for the compounds of formula II.

64. The liquid crystalline medium according to claim 13, wherein the one or more compounds of Formula II are of one or more of the following formulae ##STR00168## in which Y.sup.1 is H or F, and R.sup.21 and R.sup.22 are defined as for the compounds of formula II.

65. The liquid crystalline medium according to claim 14, wherein the one or more compounds of Formula II are of one or more of the following formulae ##STR00169## in which Y.sup.1 is H or F, and R.sup.21 and R.sup.22 are defined as for the compounds of formula II.

66. The liquid crystalline medium according to claim 15, wherein the one or more compounds of Formula II are of one or more of the following formulae ##STR00170## in which Y.sup.1 is H or F, and R.sup.21 and R.sup.22 are defined as for the compounds of formula II.

67. The liquid crystalline medium according to claim 16, wherein the one or more compounds of Formula II are of one or more of the following formulae ##STR00171## in which Y.sup.1 is H or F, and R.sup.21 and R.sup.22 are defined as for the compounds of formula II.

68. The liquid crystalline medium according to claim 17, wherein the one or more compounds of Formula II are of one or more of the following formulae ##STR00172## in which Y.sup.1 is H or F, and R.sup.21 and R.sup.22 are defined as for the compounds of formula II.

69. The liquid crystalline medium according to claim 18, wherein the one or more compounds of Formula II are of one or more of the following formulae ##STR00173## in which Y.sup.1 is H or F, and R.sup.21 and R.sup.22 are defined as for the compounds of formula II.

70. The liquid crystalline medium according to claim 19, wherein the one or more compounds of Formula II are of one or more of the following formulae ##STR00174## in which Y.sup.1 is H or F, and R.sup.21 and R.sup.22 are defined as for the compounds of formula II.

71. The liquid crystalline medium according to claim 20, wherein the one or more compounds of Formula II are of one or more of the following formulae ##STR00175## in which Y.sup.1 is H or F, and R.sup.21 and R.sup.22 are defined as for the compounds of formula II.

72. The liquid crystalline medium according to claim 21, wherein the one or more compounds of Formula II are of one or more of the following formulae ##STR00176## in which Y.sup.1 is H or F, and R.sup.21 and R.sup.22 are defined as for the compounds of formula II.

73. The liquid crystalline medium according to claim 22, wherein the one or more compounds of Formula II are of one or more of the following formulae ##STR00177## in which Y.sup.1 is H or F, and R.sup.21 and R.sup.22 are defined as for the compounds of formula II.

74. The liquid crystalline medium according to claim 23, wherein the one or more compounds of Formula II are of one or more of the following formulae ##STR00178## in which Y.sup.1 is H or F, and R.sup.21 and R.sup.22 are defined as for the compounds of formula II.

75. The liquid-crystalline medium according to claim 2, wherein the one or more compounds of Formula II contain or are a compound of the formula CC-3-V: ##STR00179##

76. The liquid-crystalline medium according to claim 3, wherein the one or more compounds of Formula II contain or are a compound of the formula CC-3-V: ##STR00180##

77. The liquid-crystalline medium according to claim 4, wherein the one or more compounds of Formula II contain or are a compound of the formula CC-3-V: ##STR00181##

78. The liquid-crystalline medium according to claim 5, wherein the one or more compounds of Formula II contain or are a compound of the formula CC-3-V: ##STR00182##

79. The liquid-crystalline medium according to claim 10, wherein the one or more compounds of Formula II contain or are a compound of the formula CC-3-V: ##STR00183##

80. The liquid-crystalline medium according to claim 11, wherein the one or more compounds of Formula II contain or are a compound of the formula CC-3-V: ##STR00184##

81. The liquid-crystalline medium according to claim 12, wherein the one or more compounds of Formula II contain or are a compound of the formula CC-3-V: ##STR00185##

82. The liquid-crystalline medium according to claim 13, wherein the one or more compounds of Formula II contain or are a compound of the formula CC-3-V: ##STR00186##

83. The liquid-crystalline medium according to claim 14, wherein the one or more compounds of Formula II contain or are a compound of the formula CC-3-V: ##STR00187##

84. The liquid-crystalline medium according to claim 15, wherein the one or more compounds of Formula II contain or are a compound of the formula CC-3-V: ##STR00188##

85. The liquid-crystalline medium according to claim 16, wherein the one or more compounds of Formula II contain or are a compound of the formula CC-3-V: ##STR00189##

86. The liquid-crystalline medium according to claim 17, wherein the one or more compounds of Formula II contain or are a compound of the formula CC-3-V: ##STR00190##

87. The liquid-crystalline medium according to claim 18, wherein the one or more compounds of Formula II contain or are a compound of the formula CC-3-V: ##STR00191##

88. The liquid-crystalline medium according to claim 19, wherein the one or more compounds of Formula II contain or are a compound of the formula CC-3-V: ##STR00192##

89. The liquid-crystalline medium according to claim 20, wherein the one or more compounds of Formula II contain or are a compound of the formula CC-3-V: ##STR00193##

90. The liquid-crystalline medium according to claim 21, wherein the one or more compounds of Formula II contain or are a compound of the formula CC-3-V: ##STR00194##

91. The liquid-crystalline medium according to claim 22, wherein the one or more compounds of Formula II contain or are a compound of the formula CC-3-V: ##STR00195##

92. The liquid-crystalline medium according to claim 23, wherein the one or more compounds of Formula II contain or are a compound of the formula CC-3-V: ##STR00196##

93. The liquid-crystalline medium according to claim 25, wherein the one or more compounds of Formula II contain or are a compound of the formula CC-3-V: ##STR00197##

Description

EXAMPLES

(1) The following examples are intended to explain the invention without limiting it. However, they illustrate the range of properties which can preferably be achieved, as well as the compounds preferably to be employed.

(2) The liquid-crystal media are investigated with respect to their applicational properties. In particular, their respective electro-optical characteristic lines, response times and their voltage holding ratio in test cells are determined.

(3) The indicated values for the above-mentioned properties are generally average values of the measurements of two test cells in each case. The deviations between the results of the individual cells were generally a maximum of 4 to 5%.

Example 1

(4) Three liquid-crystal mixtures are achieved, all of which have virtually the same values of the clearing point, the birefringence, the dielectric anisotropy and even the rotational viscosity, but differ significantly in the value of the calculated peak times or the predicted response times (t.sub.max or t.sub.max/n.sup.2) respectively. The mixture M-2 is a mixture which consists of equal parts of M1 and M-3. The compositions of the mixtures are shown in the following table, the investigation results in the table after next.

(5) TABLE-US-00007 TABLE 1a Example No. 1-1 1-2 1-3 Mixture No. M-1 M-2 M-3 Composition Compound Concentration/% CY-3-O4 18.0 15.0 12.0 CY-5-O2 6.0 12.0 CY-5-O4 13.0 12.5 12.0 CCY-3-O2 8.0 9.5 11.0 CCY-4-O2 8.0 4.0 CCY-5-O2 5.0 10.0 CCY-2-1 8.0 4.0 CCY-3-1 8.0 4.0 CPY-2-O2 4.0 8.0 PYP-2-3 5.0 2.5 CC-3-V 8.0 16.0 CC-3-V1 8.0 8.5 9.0 CC-4-V 10.0 5.0 CC-3-4 8.0 4.0 CC-3-5 6.0 7.0 8.0 CCP-V-1 1.0 2.0 100.0 100.0 100.0

(6) TABLE-US-00008 TABLE 1b Example No. 1-1 1-2 1-3 Mixture No. M-1 M-2 M-3 Physical properties T(N.I)/ C. 70.4 70.0 70.0 n.sub.e [589 nm, 20 C.] 1.5586 1.5588 1.5564 n.sub.o [589 nm, 20 C.] 1.4764 1.4767 1.4738 n [589 nm, 20 C.] 0.0822 0.0821 0.0826 .sub. [1 kHz, 20 C.] 3.4 3.5 3.6 .sub. [1 kHz, 20 C.] 6.6 6.9 7.4 [1 kHz, 20 C.] 3.2 3.4 3.8 .sub.av.[1 kHz, 20 C.] 5.53 5.83 6.13 [20 C.]/mm.sup.2 s.sup.1 20 18.5 17 [0 C.]/mm.sup.2 s.sup.1 n.d. n.d. 55 .sub.1 [20 C.] mPa .Math. s 113 113 113 k.sub.1 [20 C.]/pN 12.7 13.2 12.6 k.sub.3 [20 C.]/pN 12.9 13.7 14.6 k.sub.3/k.sub.1 [20 C.] 1.02 1.04 1.16 V.sub.0 [20 C.]/V 2.14 2.11 2.08 V.sub.10 [20 C.]/V 2.54 2.57 2.48 Calculated times t.sub.max/ms 0.161 0.143 0.120 t.sub.max/n.sup.2/ms 23.9 21.1 17.7 Experimental response times: (0 V => 2 V.sub.10) .sub.on [2 V.sub.10, 20 C.]/ms 10.1 8.3 7.0 .sub.off [2 V.sub.10, 20 C.]/ms 10.6 10.0 10.8 [2 V.sub.10, 20 C.]/ms 20.7 18.3 17.8 Note: n.d. not determined.

(7) As can be seen from the results, the response time of the liquid-crystal displays decreases significantly from Example 1-1 via Example 1-2 to Example 1-3 in parallel with the predicted response time t.sub.max or t.sub.max/n.sup.2 in accordance with the teaching of the present invention.

Example 2

(8) Three liquid-crystal mixtures are achieved, all of which have virtually the same values of the clearing point, the birefringence, the dielectric anisotropy, the rotational viscosity and even in the value of the calculated peak times or response times (t.sub.max or t.sub.max/n.sup.2), but differ significantly in their composition. The mixture M-5 is a mixture which consists of equal parts of M-4 and M-6. The compositions of the mixtures are shown in the following table, the investigation results in the table after next.

(9) TABLE-US-00009 TABLE 2a Example No. 2-1 2-2 2-3 Mixture No. M-4 M-5 M-6 Composition Compound Concentration/% CY-3-O2 16.0 8.0 CY-3-O4 9.0 18.0 CY-5-O2 14.0 7.0 CY-5-O4 8.5 17.0 CCY-3-O2 12.0 11.0 10.0 CCY-5-O2 11.0 10.5 10.0 CCY-2-1 9.0 4.5 CCY-3-1 8.0 4.0 CPY-2-O2 5.0 10.0 CPY-3-O2 1.0 2.0 CC-3-4 8.0 4.0 CC-3-5 9.0 10.5 12.0 CC-5-O1 3.0 6.0 CC-5-V 7.5 15.0 CP-5-3 7.0 3.5 CP-3-O1 6.0 3.0 100.0 100.0 100.0

(10) TABLE-US-00010 TABLE 2b Example No. 2-1 2-2 2-3 Mixture No. M-4 M-5 M-6 Physical properties T(N.I)/ C. 71.0 70.0 70.0 n.sub.e [589 nm, 20 C.] 1.5587 1.5584 1.5567 n.sub.o [589 nm, 20 C.] 1.4765 1.4759 1.4746 n [589 nm, 20 C.] 0.0822 0.0825 0.0821 .sub. [1 kHz, 20 C.] 3.6 3.7 3.7 .sub. [1 kHz, 20 C.] 7.4 7.5 7.6 [1 kHz, 20 C.] 3.8 3.9 3.9 .sub.av. [1 kHz, 20 C.] 6.13 6.23 6.3 [20 C.]/mm.sup.2 s.sup.1 21 21.5 22 [0 C.]/mm.sup.2 s.sup.1 67 n.d. n.d. [20 C.]/mm.sup.2 s.sup.1 416 n.d. n.d. [30 C.]/mm.sup.2 s.sup.1 1.380 n.d. n.d. .sub.1 [20 C.] mPa .Math. s 133 130 127 k.sub.1 [20 C.]/pN 13.0 13.3 13.4 k.sub.3 [20 C.]/pN 15.1 14.0 13.1 k.sub.3/k.sub.1 [20 C.] 1.15 1.05 0.98 V.sub.0 [20 C.]/V 2.10 2.01 1.92 V.sub.10 [20 C.]/V 2.53 2.44 2.40 Calculated times t.sub.max/ms 0.147 0.145 0.147 t.sub.max/n.sup.2/ms 21.8 21.3 21.8 Experimental response times: (0 V => 2 V.sub.10) .sub.on [2 V.sub.10, 20 C.]/ms 10.0 7.6 7.3 .sub.off [2 V.sub.10, 20 C.]/ms 11.7 12.0 11.4 [2 V.sub.10, 20 C.]/ms 21.7 19.6 18.7 Note: n.d. not determined.

(11) As can be seen from the results, all three mixtures of this example have good response times in accordance with their low value for t.sub.max or t.sub.max/n.sup.2, in accordance with the teaching of the present invention.

(12) As can furthermore be seen from the results, the response time of the liquid-crystal displays additionally decreases significantly from Example 2-1 via Example 2-2 to Example 2-3 in parallel to the change in the composition of the mixtures, in accordance with the preferred teaching of the present invention.

(13) The liquid-crystal mixtures of Examples 1 and 2 are particularly distinguished by good response times, this applies in particular to mixtures M-2, M-3, M-5 and M-6. The liquid-crystal mixtures of Examples 1 and 2, particularly the four mixtures just mentioned, can advantageously be used in ECB displays of all known designs, such as, for example: MVA, PVA and ASV, and also in IPS and PA LCD displays.