LIQUID-CRYSTALLINE MEDIUM AND LIQUID-CRYSTAL DISPLAY COMPRISING THE SAME

Abstract

The invention relates to a liquid-crystalline medium, preferably having a nematic phase and negative dielectric anisotropy, which comprises a) one or more compounds of formula I

##STR00001## and b) one or more compounds selected from the group of compounds of the formulae II and III

##STR00002##

in which the parameters have the respective meanings indicated in claim 1, to the use thereof in an electro-optical display, particularly in an active-matrix display based on the VA, ECB, PALC, IPS or FFS effect, to displays of this type which contain a liquid-crystalline medium of this type, and to the use of the compounds of formula I for reduction of the dispersion of the birefringence of a liquid-crystalline medium which comprises one or more compounds of the formulae II and/or III.

Claims

1. Liquid-crystalline medium comprising a) one or more compounds of formula I ##STR00229## in which a, b and c independently of each other denote an integer of 0 or 1, (a+b+c) is 1, 2 or 3, R.sup.11 and R.sup.12 independently of each other denote H or alkyl with 1 to 5 C atoms, and b) one or more compounds selected from the group of compounds of the formulae II and III ##STR00230## in which R.sup.21 denotes an unsubstituted alkyl radical having 1 to 7 C atoms, an unsubstituted alkenyl radical having 2 to 7 C atoms or an unsubstituted alkoxy radical having 1 to 6 C atoms, R.sup.22 denotes an unsubstituted alkyl radical having 1 to 7 C atoms, an unsubstituted alkoxy radical having 1 to 6 C atoms or an unsubstituted alkenyloxy radical having 2 to 6 C atoms, and I denotes 0 or 1, R.sup.31 denotes an unsubstituted alkyl radical having 1 to 7 C atoms or an unsubstituted alkenyl radical having 2 to 7 C atoms, R.sup.32 denotes an unsubstituted alkyl radical having 1 to 7 C atoms, an unsubstituted alkoxy radical having 1 to 6 C atoms or an unsubstituted alkenyloxy radical having 2 to 6 C atoms, and ##STR00231## denotes ##STR00232##

2. Medium according to claim 1, characterised in that it comprises one or more compounds of formula I selected from the group of the compounds of the formulae I-1 to I-3 ##STR00233## in which the parameters have the meanings indicated in claim 1.

3. Medium according to claim 1, characterised in that it comprises one or more compounds of formula IV ##STR00234## in which R.sup.41 denotes an unsubstituted alkyl radical having 1 to 7 C atoms or an unsubstituted alkenyl radical having 2 to 7 C atoms, and R.sup.42 denotes an unsubstituted alkyl radical having 1 to 7 C atoms or an unsubstituted alkoxy radical having 1 to 6 C atoms,

4. Liquid-crystalline medium according to claim 1, characterised in that it comprises one or more compounds of formula V ##STR00235## in which R.sup.51 and R.sup.52, independently of one another, have one of the meanings given for R.sup.21 and R.sup.22 in claim 1, ##STR00236## if present, each, independently of one another, denote ##STR00237## Z.sup.51 to Z.sup.53 each, independently of one another, denote —CH.sub.2—CH.sub.2—, —CH.sub.2—O—, —CH═CH—, —C≡C—, —COO— or a single bond, and i and j each, independently of one another, denote 0 or 1.

5. Liquid-crystalline medium according to claim 1, characterised in that it one or more compounds of formula II and/or III selected from the group of the compounds of the formulae II-1, II-2, III-1 and III-2 ##STR00238## in which the parameters have the respective meanings given in claim 1.

6. Liquid-crystalline medium according to claim 5, characterised in that it comprises one or more compounds of formula II selected from the group of the compounds of the formulae II-1 and II-2 ##STR00239##

7. Medium according to claim 1, characterised in that the total concentration of the compounds of formula I in the medium as a whole is 5% or more to 35% or less.

8. Medium according to claim 1, characterised in that the total concentration of the compounds of formula II in the medium as a whole is 25% or more to 45% or less.

9. Medium according to claim 1, characterised in that it additionally comprises one or more chiral compounds.

10. Electro-optical display or electro-optical component, characterised in that it comprises a liquid-crystalline medium according to claim 1.

11. Display according to claim 10, characterised in that it is based on the VA-, ECB- IPS- or FFS mode.

12. Display according to claim 10, characterised in that it contains an active-matrix addressing device.

13. Use of a medium according to claim 1 in an electro-optical display or in an electro-optical component.

14. Display according to claim 10, characterised in that it is a mobile display.

15. Process for the preparation of a liquid-crystalline medium according to claim 1, characterised in that one or more compounds of formula I are mixed with one or more compounds of formula II and/or one or more compounds selected from the group of the compounds of the formulae III, IV and V.

Description

EXAMPLES

[0279] The following examples explain the present invention without restricting it in any way. However, the physical properties make it clear to the person skilled in the art what properties can be achieved and in what ranges they can be modified. In particular, the combination of the various properties which can preferably be achieved is thus well defined for the person skilled in the art.

Comparative Example 1

[0280] The following mixture (C-1) is prepared and investigated.

TABLE-US-00007 Mixture C-1 Composition Compound Concentration /% No. Abbreviation by weight 1 CY-3-O2 21.0 2 CY-5-O2 4.5 3 CCY-3-O1 11.5 4 CCY-3-O2 7.5 5 CLY-3-O2 4.5 6 CLY-3-O3 3.0 7 CPY-2-O2 4.5 8 CPY-3-O2 4.5 9 PYP-2-4 4.5 10 CC-3-V 33.5 11 CCP-V-1 1.0 Σ 100.0 Physical properties T (N, I) = 74.0° C. n.sub.e (20° C., 589 nm) = 1.5736 Δn (20° C., 589 nm) = 0.0931 ε.sub.⊥ (20°, 1 kHz) = 7.5 Δε (20°, 1 kHz) = −3.8 γ.sub.1 (20° C.) = 93 mPa .Math. s k.sub.11 (20° C.) = 12.5 pN k.sub.33 (20° C.) = 14.9 pN V.sub.0 (20° C.) = 2.08 V

[0281] Mixture C-1 is characterized by a relatively large wavelength dispersion of the birefringence, which is

Δ(Δn)=Δn(20° C., 436 nm)−Δn(20° C.,633 nm)=0.0112, and thus rather high. Here the accuracy of the value of Δ(Δn) has to be taken as about +/−0.0004, i.e. double the value of the individual Δn-values.

Example 1

[0282] The following mixture (M-1) is prepared and investigated.

TABLE-US-00008 Mixture M-1 Composition Compound Concentration /% No. Abbreviation by weight 1 CY-3-O2 25.0 2 CY-5-O2 19.0 3 CCY-3-O2 4.0 4 CLY-3-O2 5.0 5 CLY-3-O3 7.0 6 CC-V-V1 14.0 7 CCP-V-1 18.0 8 CCP-V2-1 8.0 Σ 100.0 Physical properties T (N, I) = 74.0° C. n.sub.e (20° C., 589 nm) = 1.5777 Δn (20° C., 589 nm) = 0.0939 ε.sub.⊥ (20°, 1 kHz) = 7.5 Δε (20°, 1 kHz) = −3.8 γ.sub.1 (20° C.) = 115 mPa .Math. s k.sub.11 (20° C.) = 12.8 pN k.sub.33 (20° C.) = 16.4 pN V.sub.0 (20° C.) = 2.19 V

[0283] Mixture M-1 is characterized by a comparatively small wavelength dispersion of the birefringence, which is only Δ(Δn)=Δn(20° C., 436 nm)−Δn(20° C., 633 nm)=0.0092.

Example 2

[0284] The following mixture (M-2) is prepared and investigated.

TABLE-US-00009 Mixture M-2 Composition Compound Concentration /% No. Abbreviation by weight 1 CY-3-O2 24.0 2 CY-5-O2 18.0 3 CCY-3-O2 4.0 4 CLY-3-O2 7.5 5 CLY-3-O3 7.0 6 CC-1V-V1 10.0 7 CC-3-V 9.5 8 CCP-V-1 20.0 Σ 100.0 Physical properties T (N, I) = 74.0° C. n.sub.e (20° C., 589 nm) = 1.5750 Δn (20° C., 589 nm) = 0.0932 ε.sub.⊥ (20°, 1 kHz) = 7.5 Δε (20°, 1 kHz) = −3.9 γ.sub.1 (20° C.) = 111 mPa .Math. s k.sub.11 (20° C.) = 13.3 pN k.sub.33 (20° C.) = 17.2 pN V.sub.0 (20° C.) = 2.23 V

[0285] Mixture M-2 is characterized by a rather small wavelength dispersion of the birefringence, which is only Δ(Δn)=0.0086.

Example 3

[0286] The following mixture (M-3) is prepared and investigated.

TABLE-US-00010 Mixture M-3 Composition Compound Concentration /% No. Abbreviation by weight 1 CY-3-O2 24.0 2 CY-5-O2 18.0 3 CCY-3-O2 4.0 4 CLY-3-O3 9.0 5 CLY-3-O2 5.0 6 CC-2V-V2 10.0 7 CC-3-V 8.0 8 CCP-V-1 18.0 9 CCP-V2-1 4.0 Σ 100.0 Physical properties T (N, I) = 74.0° C. n.sub.e (20° C., 589 nm) = 1.5741 Δn (20° C., 589 nm) = 0.0918 ε.sub.⊥ (20°, 1 kHz) = 7.5 Δε (20°, 1 kHz) = −3.8 γ.sub.1 (20° C.) = 111 mPa .Math. s k.sub.11 (20° C.) = 12.9 pN k.sub.33 (20° C.) = 15.5 pN V.sub.0 (20° C.) = 2.14 V

[0287] Mixture M-3 is characterized by a very small wavelength dispersion of the birefringence, which is even only Δ(Δn)=0.0082.

Example 4

[0288] The following mixture (M-4) is prepared and investigated.

TABLE-US-00011 Mixture M-4 Composition Compound Concentration /% No. Abbreviation by weight 1 CY-3-O2 24.0 2 CY-5-O2 18.0 3 CCY-3-O1 5.0 4 CCY-3-O2 8.0 5 CCY-3-O3 8.0 6 CC-3-VV 25.0 7 CC-3-V 5.0 8 CCP-V-1 7.0 Σ 100.0 Physical properties T (N, I) = 74.0° C. n.sub.e (20° C., 589 nm) = 1.5706 Δn (20° C., 589 nm) = 0.0921 ε.sub.⊥ (20°, 1 kHz) = 7.6 Δε (20°, 1 kHz) = −3.8 γ.sub.1 (20° C.) = 106 mPa .Math. s k.sub.11 (20° C.) = 12.6 pN k.sub.33 (20° C.) = 16.3 pN V.sub.0 (20° C.) = 2.19 V

[0289] Mixture M-4 is characterized by a rather small wavelength dispersion of the birefringence, which is only Δ(Δn)=0.0087.

Example 5

[0290] The following mixture (M-5) is prepared and investigated.

TABLE-US-00012 Mixture M-5 Composition Compound Concentration /% No. Abbreviation by weight 1 CY-3-O2 22.0 2 CY-5-O2 18.0 3 CCY-3-O2 12.0 4 CLY-3-O3 12.0 5 CC-3-VV 27.0 6 CC-3-V 9.0 Σ 100.0 Physical properties T (N, I) = 74.0° C. n.sub.e (20° C., 589 nm) = 1.5700 Δn (20° C., 589 nm) = 0.0927 ε.sub.⊥ (20°, 1 kHz) = 7.7 Δε (20°, 1 kHz) = −3.9 γ.sub.1 (20° C.) = 102 mPa .Math. s k.sub.11 (20° C.) = 13.0 pN k.sub.33 (20° C.) = 16.0 pN V.sub.0 (20° C.) = 2.15 V

[0291] Mixture M-5 is characterized by a relatively small wavelength dispersion of the birefringence, which is only Δ(Δn)=0.0094.

Example 6

[0292] The following mixture (M-6) is prepared and investigated.

TABLE-US-00013 Mixture M-6 Composition Compound Concentration /% No. Abbreviation by weight 1 CY-3-O2 24.0 2 CY-5-O2 18.0 3 CCY-3-O1 5.0 4 CLY-3-O2 6.0 5 CLY-3-O3 6.0 6 CVC-3-V 14.0 7 CCP-V-1 22.0 8 CCP-V2-1 5.0 Σ 100.0 Physical properties T (N, I) = 75.0° C. n.sub.e (20° C., 589 nm) = 1.5760 Δn (20° C., 589 nm) = 0.0924 ε.sub.⊥ (20°, 1 kHz) = 7.4 Δε (20°, 1 kHz) = −3.7 γ.sub.1 (20° C.) = 118 mPa .Math. s k.sub.11 (20° C.) = 12.2 pN k.sub.33 (20° C.) = 15.6 pN V.sub.0 (20° C.) = 2.18 V

[0293] Mixture M-6 is characterized by a very small wavelength dispersion of the birefringence, which is only Δ(Δn)=0.0083.

Example 7

[0294] The following mixture (M-7) is prepared and investigated.

TABLE-US-00014 Mixture M-7 Composition Compound Concentration/ No. Abbreviation % by weight 1 CY-3-O2 18.0 2 CY-5-O2 17.0 3 CCY-3-O1 4.0 4 CLY-3-O2 12.0 5 CLY-3-O3 7.0 6 PY-3-O2 2.0 7 CC-V-V1 23.0 8 CCP-V-1 17.0 Σ 100.0 Physical properties T (N, I) = 75.0° C. n.sub.e (20° C., 589 nm) = 1.5789 Δn (20° C., 589 nm) = 0.0955 ε.sub.⊥ (20°, 1 kHz) = 7.4 Δε (20°, 1 kHz) = −3.8 γ.sub.1 (20° C.) = 108 mPa .Math. s k.sub.11 (20° C.) = 12.9 pN k.sub.33 (20° C.) = 16.4 pN V.sub.0 (20° C.) = 2.26 V

[0295] Mixture M-7 is characterized by a rather small wavelength dispersion of the birefringence, which is only Δ(Δn)=0.0090.

Example 8

[0296] The following mixture (M-8) is prepared and investigated.

TABLE-US-00015 Mixture M-8 Composition Compound Concentration/ No. Abbreviation % by weight 1 CY-3-O2 20.0 2 CY-5-O2 17.0 3 CCY-3-O1 4.0 4 CLY-3-O2 20.0 5 CLY-3-O3 6.0 6 CC-V-V1 14.0 7 CCP-V-1 17.0 Σ 100.0 Physical properties T (N, I) = 78.5° C. n.sub.e (20° C., 589 nm) = 1.5786 Δn (20° C., 589 nm) = 0.0957 ε.sub.⊥ (20°, 1 kHz) = 7.7 Δε (20°, 1 kHz) = −4.0 γ.sub.1 (20° C.) = 116 mPa .Math. s k.sub.11 (20° C.) = 13.6 pN k.sub.33 (20° C.) = 17.7 pN V.sub.0 (20° C.) = 2.22 V

[0297] Mixture M-8 is characterized by a rather small wavelength dispersion of the birefringence, which is only Δ(Δn)=0.0089.

Example 9

[0298] The following mixture (M-9) is prepared and investigated.

TABLE-US-00016 Mixture M-9 Composition Compound Concentration/ No. Abbreviation % by weight 1 CY-3-O2 24.0 2 CY-3-O4 4.0 3 CY-5-O2 12.0 4 CCY-3-O1 6.0 5 CLY-3-O2 9.0 6 CLY-3-O3 7.0 7 PY-3-O2 1.0 8 CC-1V-V1 8.0 9 CC-3-V 10.0 10  CCP-V-1 19.0 Σ 100.0 Physical properties T (N, I) = 74.5° C. n.sub.e (20° C., 589 nm) = 1.5767 Δn (20° C., 589 nm) = 0.0942 ε.sub.⊥ (20°, 1 kHz) = 7.8 Δε (20°, 1 kHz) = −4.1 γ.sub.1 (20° C.) = 120 mPa .Math. s k.sub.11 (20° C.) = 13.1 pN k.sub.33 (20° C.) = 16.8 pN V.sub.0 (20° C.) = 2.14 V

[0299] Mixture M-9 is characterized by a rather small wavelength dispersion of the birefringence, which is only Δ(Δn)=0.0089.

Example 10

[0300] The following mixture (M-10) is prepared and investigated.

TABLE-US-00017 Mixture M-10 Composition Compound Concentration/ No. Abbreviation % by weight 1 CY-3-O2 10.0 2 CY-3-O4 8.0 3 CY-5-O2 8.0 4 CLY-2-O4 10.0 5 CLY-3-O2 10.0 6 CLY-3-O3 10.0 7 PY-3-O2 3.0 8 CC-1V-V1 21.0 9 CC-3-V 20.0 Σ 100.0 Physical properties T (N, I) = 74.0° C. n.sub.e (20° C., 589 nm) = 1.5695 Δn (20° C., 589 nm) = 0.0913 ε.sub.⊥ (20°, 1 kHz) = 7.0 Δε (20°, 1 kHz) = −3.6 γ.sub.1 (20° C.) = 97 mPa .Math. s k.sub.11 (20° C.) = 14.3 pN k.sub.33 (20° C.) = 17.3 pN V.sub.0 (20° C.) = 2.32 V

[0301] Mixture M-10 is characterized by a rather small wavelength dispersion of the birefringence, which is only Δ(Δn)=0.0085.

Example 11

[0302] The following mixture (M-11) is prepared and investigated.

TABLE-US-00018 Mixture M-11 Composition Compound Concentration/ No. Abbreviation % by weight 1 CY-3-O2 20.0 2 CY-5-O2 18.0 3 CCY-3-O2 2.0 4 CLY-3-O2 9.0 5 CLY-3-O3 5.0 6 CC-2V-V2 12.0 7 CC-3-V 4.0 8 CCP-V-1 18.0 9 CCP-V2-1 6.0 Σ 100.0 Physical properties T (N, I) = 74.0° C. n.sub.e (20° C., 589 nm) = 1.5755 Δn (20° C., 589 nm) = 0.0928 ε.sub.⊥ (20°, 1 kHz) = 7.7 Δε (20°, 1 kHz) = −3.8 γ.sub.1 (20° C.) = 113 mPa .Math. s k.sub.11 (20° C.) = 12.9 pN k.sub.33 (20° C.) = 15.4 pN V.sub.0 (20° C.) = 2.13 V

[0303] Mixture M-11 is characterized by a rather small wavelength dispersion of the birefringence, which is only Δ(Δn)=0.0085.

Example 12

[0304] The following mixture (M-12) is prepared and investigated.

TABLE-US-00019 Mixture M-12 Composition Compound Concentration/ No. Abbreviation % by weight 1 CY-3-O2 27.0 2 CY-5-O2 13.0 3 CLY-3-O2 15.0 4 CLY-3-O3 8.0 5 CC-3-VV 18.0 6 CC-3-V 10.0 7 CCP-V-1 95.0 Σ 100.0 Physical properties T (N, I) = 76.0° C. n.sub.e (20° C., 589 nm) = 1.5766 Δn (20° C., 589 nm) = 0.0962 ε.sub.⊥ (20°, 1 kHz) = 7.8 Δε (20°, 1 kHz) = −4.0 γ.sub.1 (20° C.) = 106 mPa .Math. s k.sub.11 (20° C.) = 13.3 pN k.sub.33 (20° C.) = 16.4 pN V.sub.0 (20° C.) = 2.14 V

[0305] Mixture M-12 is characterized by a relatively small wavelength dispersion of the birefringence, which is Δ(Δn)=0.0106.

Example 13

[0306] The following mixture (M-13) is prepared and investigated.

TABLE-US-00020 Mixture M-13 Composition Compound Concentration/ No. Abbreviation % by weight 1 CY-3-O2 20.0 2 CY-5-O2 18.0 3 CCY-3-O2 5.0 4 CLY-3-O2 9.0 5 CLY-3-O3 5.0 6 PY-3-O2 3.0 7 CC-3-VV 17.0 7 CC-3-V 11.0 8 CCP-V-1 8.0 Σ 100.0 Physical properties T (N, I) = 74.0° C. n.sub.e (20° C., 589 nm) = 1.5757 Δn (20° C., 589 nm) = 0.0960 ε.sub.⊥ (20°, 1 kHz) = 7.8 Δε (20°, 1 kHz) = −4.0 γ.sub.1 (20° C.) = 109 mPa .Math. s k.sub.11 (20° C.) = 13.2 pN k.sub.33 (20° C.) = 15.8 pN V.sub.0 (20° C.) = 2.13 V

[0307] Mixture M-13 is characterized by a relatively small wavelength dispersion of the birefringence, which is Δ(Δn)=0.0103.

Example 14

[0308] The following mixture (M-14) is prepared and investigated.

TABLE-US-00021 Mixture M-14 Composition Compound Concentration/ No. Abbreviation % by weight 1 CY-3-O2 20.0 2 CY-5-O2 18.0 3 CCY-3-O3 5.0 4 CCY-5-O2 4.0 5 CLY-3-O2 9.0 6 CLY-3-O3 5.0 7 PY-3-O2 3.0 8 CC-3-VV 17.0 9 CC-3-V 11.0 10  CCP-V-1 8.0 Σ 100.0 Physical properties T (N, I) = 73.5° C. n.sub.e (20° C., 589 nm) = 1.5750 Δn (20° C., 589 nm) = 0.0924 ε.sub.⊥ (20°, 1 kHz) = 7.4 Δε (20°, 1 kHz) = −4.0 γ.sub.1 (20° C.) = 108 mPa .Math. s k.sub.11 (20° C.) = 13.0 pN k.sub.33 (20° C.) = 15.8 pN V.sub.0 (20° C.) = 2.11 V

[0309] Mixture M-14 is characterized by a comparatively small wavelength dispersion of the birefringence, which is only Δ(Δn)=0.0097.

Example 15

[0310] The following mixture (M-15) is prepared and investigated.

TABLE-US-00022 Mixture M-15 Composition Compound Concentration/ No. Abbreviation % by weight 1 CY-3-O2 19.0 2 CY-5-O2 20.0 3 CLY-3-O2 14.0 4 CLY-3-O3 12.0 5 CC-3-VV 24.0 6 CC-3-V 11.0 Σ 100.0 Physical properties T (N, I) = 75.5° C. n.sub.e (20° C., 589 nm) = 1.5736 Δn (20° C., 589 nm) = 0.0956 ε.sub.⊥ (20°, 1 kHz) = 7.8 Δε (20°, 1 kHz) = −4.0 γ.sub.1 (20° C.) = 104 mPa .Math. s k.sub.11 (20° C.) = 13.6 pN k.sub.33 (20° C.) = 16.2 pN V.sub.0 (20° C.) = 2.11 V

[0311] Mixture M-15 is characterized by a comparatively small wavelength dispersion of the birefringence, which is only Δ(Δn)=0.0098.

Example 16

[0312] The following mixture (M-16) is prepared and investigated.

TABLE-US-00023 Mixture M-16 Composition Compound Concentration/ No. Abbreviation % by weight 1 CY-3-O2 17.5 2 CCY-3-O1 &.0 3 CCY-3-O2 10.0 4 CCY-5-O2 5.0 5 CLY-3-O2 6.0 6 CLY-3-O3 6.5 7 Y-4O-O4V 12.0 8 CC-3-VV 35.0 9 CC-3-V 3.0 Σ 100.0 Physical properties T (N, I) = 75.5° C. n.sub.e (20° C., 589 nm) = 1.5718 Δn (20° C., 589 nm) = 0.0943 ε.sub.⊥(20°, 1 kHz) = 8.2 Δε (20°, 1 kHz) = −4.1 γ.sub.1 (20° C.) = 94 mPa .Math. s k.sub.11 (20° C.) = 12.9 pN k.sub.33 (20° C.) = 16.0 pN V.sub.0 (20° C.) = 2.10 V

[0313] Mixture M-16 is characterized by a relatively small wavelength dispersion of the birefringence, which is Δ(Δn)=0.0105.

Example 17

[0314] The following mixture (M-17) is prepared and investigated.

TABLE-US-00024 Mixture M-17 Composition Compound Concentration/ No. Abbreviation % by weight 1 CY-3-O2 9.0 2 CCY-2-O2 10.0 3 CCY-3-O1 14.0 4 CLY-3-O2 14.0 5 PY-1-O4 5.0 6 PY-3-O2 5.0 7 PY-4-O2 5.0 8 CC-3-VV 7.0 9 CC-3-V 31.0 Σ 100.0 Physical properties T (N, I) = 77.5° C. n.sub.e (20° C., 589 nm) = 1.5773 Δn (20° C., 589 nm) = 0.0957 ε.sub.⊥ (20°, 1 kHz) = 7.4 Δε (20°, 1 kHz) = −3.7 γ.sub.1 (20° C.) = 97 mPa .Math. s k.sub.11 (20° C.) = 13.7 pN k.sub.33 (20° C.) = 15.6 pN V.sub.0 (20° C.) = 2.16 V

Example 18

[0315] The following mixture (M-18) is prepared and investigated.

TABLE-US-00025 Mixture M-18 Composition Compound Concentration/ No. Abbreviation % by weight 1 CY-3-O2 22.0 2 CY-5-O2 15.0 3 CLY-3-O2 14.0 4 CLY-3-O3 5.0 5 CC-3-VV 31.0 6 CC-3-V 13.0 Σ 100.0 Physical properties T (N, I) = 72.5° C. n.sub.e (20° C., 589 nm) = 1.5700 Δn (20° C., 589 nm) = 0.0927 ε.sub.⊥ (20°, 1 kHz) = 6.9 Δε (20°, 1 kHz) = −3.2 γ.sub.1 (20° C.) = 84 mPa .Math. s k.sub.11 (20° C.) = 13.0 pN k.sub.33 (20° C.) = 16.2 pN V.sub.0 (20° C.) = 2.37 V

Example 19

[0316] The following mixture (M-19) is prepared and investigated.

TABLE-US-00026 Mixture M-19 Composition Compound Concentration/ No. Abbreviation % by weight 1 CY-3-O2 10.0 2 CY-3-O4 8.0 3 CY-5-O2 8.0 4 CLY-2-O4 10.0 5 CLY-3-O2 7.0 6 CLY-3-O3 10.0 7 PY-3-O2 5.0 8 CC-3-VV 6.0 9 CC-1V-V1 21.0 10  CC-3-V 15.0 Σ 100.0 Physical properties T (N, I) = 73.0° C. n.sub.e (20° C., 589 nm) = 1.5728 Δn (20° C., 589 nm) = 0.0942 ε.sub.⊥ (20°, 1 kHz) = 7.0 Δε (20°, 1 kHz) = −3.5 γ.sub.1 (20° C.) = 97 mPa .Math. s k.sub.11 (20° C.) = 14.2 pN k.sub.33 (20° C.) = 17..2 pN V.sub.0 (20° C.) = 2.35 V

Example 20

[0317] The following mixture (M-20) is prepared and investigated.

TABLE-US-00027 Mixture M-20 Composition Compound Concentration/ No. Abbreviation % by weight 1 CY-3-O2 22.0 2 CY-5-O2 15.0 3 CLY-3-O2 14.0 4 CLY-3-O3 5.0 5 CC-3-VV 20.0 6 CC-3-VV1 7.0 7 CC-3-V 17.0 Σ 100.0 Physical properties T (N, I) = 72.5° C. n.sub.e (20° C., 589 nm) = 1.5690 Δn (20° C., 589 nm) = 0.0917 ε.sub.⊥ (20°, 1 kHz) = 6.9 Δε (20°, 1 kHz) = −3.2 γ.sub.1 (20° C.) = t.b.d. mPa .Math. s k.sub.11 (20° C.) = t.b.d. pN k.sub.33 (20° C.) = t.b.d. pN V.sub.0 (20° C.) = t.b.d. V Note: t.b.d.: to be determined.

Example 21

[0318] The following mixture (M-21) is prepared and investigated.

TABLE-US-00028 Mixture M-21 Composition Compound Concentration/ No. Abbreviation % by weight 1 CY-3-O2 27.0 2 CY-5-O2 13.0 3 CLY-3-O2 15.0 4 CLY-3-O3 8.0 5 CC-3-VV 9.0 6 CC-3-VV1 6.0 7 CC-3-V 13.0 8 CCP-V-1 9.0 Σ 100.0 Physical properties T (N, I) = 76.5° C. n.sub.e (20° C., 589 nm) = 1.5759 Δn (20° C., 589 nm) = 0.0955 ε.sub.⊥ (20°, 1 kHz) = 7.8 Δε (20°, 1 kHz) = −4.0 γ.sub.1 (20° C.) = t.b.d. mPa .Math. s k.sub.11 (20° C.) = t.b.d. pN k.sub.33 (20° C.) = t.b.d. pN V.sub.0 (20° C.) = t.b.d. V Note: t.b.d.: to be determined.

[0319] Mixtures M-17 to M-21 are characterized by a comparatively small or at least a relatively small wavelength dispersion of the birefringence, similar to those observed for the previous examples.