Liquid-crystalline media, components for high-frequency technology, and mesogenic compounds

Abstract

The present invention relates to a liquid-crystal medium which comprises a component A which consists of one or more compounds selected from the group of the formulae I-M and I-U ##STR00001##
in which the parameters have the respective meanings given in the claims or in the text, and to the corresponding, novel mesogenic compounds and to the preparation thereof. The present invention likewise relates to the use of these liquid-crystal media, in particular in components for high-frequency technology, and to components of this type which contain media according to the invention, and to the production and use of these components. The components according to the invention are suitable, in particular, as phase shifters in the microwave and millimeter wave region, for microwave and millimeter wave array antennae and very particularly for so-called tuneable reflectarrays.

Claims

1. A liquid-crystal medium, comprising one or more compounds of formulae I-M or I-U, ##STR00294## wherein R.sup.1 is alkyl, which is straight chain or branched, is un-substituted, mono- or poly-substituted by F, Cl or CN, and in which one or more CH.sub.2 groups are optionally replaced, in each case independently from one another, by O, S, NR.sup.01, SiR.sup.01R.sup.02, CO, COO, OCO, OCOO, SCO, COS, CY.sup.01CY.sup.02 or CC in such a manner that O and/or S atoms are not linked directly to one another, L.sup.1 is F, X.sup.1 is F, CN or CF.sub.3, Y.sup.01 and Y.sup.02 are, independently of each other, F, Cl or CN, and alternatively one of them may be H, and R.sup.01 and R.sup.02 are, independently of each other, H or alkyl with 1 to 12 C-atoms and comprising one or more compounds of formula I ##STR00295## wherein ##STR00296## denotes ##STR00297## L.sup.1 denotes H, alkyl having 1 to 6 C atoms, cycloalkyl having 3 to 6 C atoms or cycloalkenyl having 4 to 6 C atoms, X.sup.1 denotes H, alkyl having 1 to 3 C atoms or halogen, R.sup.11 to R.sup.14, independently of one another, denote unfluorinated alkyl or unfluorinated alkoxy, each having 1 to 15 C atoms, unfluorinated alkenyl, unfluorinated alkenyloxy or unfluorinated alkoxyalkyl, each having 2 to 15 C atoms, or cycloalkyl, alkylcycloalkyl, cycloalkenyl, alkylcycloalkenyl, alkylcycloalkylalkyl or alkylcycloalkenylalkyl, each having up to 15 C atoms, and alternatively one of R.sup.13 and R.sup.14 or both also denote H.

2. A liquid-crystal medium according to claim 1, wherein ##STR00298## denotes ##STR00299## L.sup.1 denotes H, alkyl having 1 to 6 C atoms, cycloalkyl having 3 to 6 C atoms or cycloalkenyl having 4 to 6 C atoms, X.sup.1 denotes H, alkyl having 1 to 3 C atoms or halogen, R.sup.13 to R.sup.14, independently of one another, denote unfluorinated alkyl or unfluorinated alkoxy, each having 1 to 15 C atoms, unfluorinated alkenyl, unfluorinated alkenyloxy or unfluorinated alkoxyalkyl, each having 2 to 15 C atoms, or cycloalkyl, alkylcycloalkyl, cycloalkenyl, alkylcycloalkenyl, alkylcycloalkylalkyl or alkylcycloalkenylalkyl, each having up to 15 C atoms, and alternatively one of R.sup.13 and R.sup.14 or both also denote H.

3. A liquid-crystal medium according to claim 1, wherein the one or more compounds of formula I comprise one or more compounds of formula I-2 ##STR00300## wherein R.sup.11 and R.sup.12 have the respective meanings given in claim 1.

4. A liquid-crystal medium according to claim 1, additionally comprising one or more components C to F: a strongly dielectrically positive component, component C, which has a dielectric anisotropy of 10 or more at a temperature of 20 C. and a frequency of 1 kHz, a strongly dielectrically negative component, component D, which has a dielectric anisotropy of 5 or less at a temperature of 20 C. and a frequency of 1 kHz, a component, component E, which consists of compounds having seven or more five- or six-membered rings and has a dielectric anisotropy in the range from more than 5.0 to less than 10.0 at a temperature of 20 C. and a frequency of 1 kHz, and a component, component F, which consists of compounds having up to six five- or six-membered rings and also has a dielectric anisotropy in the range from more than 5.0 to less than 10.0 at a temperature of 20 C. and a frequency of 1 kHz.

5. A liquid-crystal medium according to claim 1, further comprising one or more compounds of the formula VI ##STR00301## in which L.sup.61 denotes R.sup.61 and, in the case where Z.sup.61 and/or Z.sup.62 denote trans-CHCH or trans-CFCF, alternatively also denotes X.sup.61, L.sup.62 denotes R.sup.62 and, in the case where Z.sup.61 and/or Z.sup.62 denote trans-CHCH or trans-CFCF, alternatively also denotes X.sup.62, R.sup.61 and R.sup.62, independently of one another, denote H, unfluorinated alkyl or unfluorinated alkoxy having 1 to 17 C atoms or unfluorinated alkenyl, unfluorinated alkenyloxy or unfluorinated alkoxyalkyl having 2 to 15 C atoms, X.sup.61 and X.sup.62, independently of one another, denote F or Cl, CN, NCS, SF.sub.5, fluorinated alkyl or alkoxy having 1 to 7 C atoms or fluorinated alkenyl, alkenyloxy or alkoxyalkyl having 2 to 7 C atoms, or NCS, one of Z.sup.61 and Z.sup.62 denotes trans-CHCH, trans-CFCF or CC and the other, independently thereof, denotes trans-CHCH, trans-CFCF or a single bond, and ##STR00302## independently of one another, denote ##STR00303##

6. A process for the preparation of a liquid-crystal medium according to claim 1, wherein one or more compounds of formula I-M and/or one or more compounds of formula I-U, are mixed with one or more compounds of formula I and/or with one or more additives.

7. A method which comprises including a liquid-crystal medium according to claim 1 in a component for high-frequency technology.

8. A component for high-frequency technology, comprising a liquid-crystal medium according to claim 1.

9. A microwave antenna array, comprising one or more components for high-frequency technology according to claim 8.

10. A process for tuning a microwave antenna array, wherein a component for high-frequency technology according to claim 8 is electrically addressed.

11. A liquid-crystal medium according to claim 1, wherein the compounds of Formula I-M and Formula I-U have X.sup.1CN.

12. A liquid-crystal medium according to claim 1, wherein the compounds of Formula I-M and Formula I-U have X.sup.1CF.sub.3.

13. A liquid-crystal medium according to claim 1, comprising compounds of formula I-M.

14. A liquid-crystal medium according to claim 1, comprising compounds of formula I-U.

15. A liquid-crystal medium according to claim 1, wherein ##STR00304## is ##STR00305##

Description

EXAMPLES

(1) The following examples illustrate the present invention without limiting it in any way. However, it becomes clear to the person skilled in the art from the physical properties 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.

(2) The acetylenes employed, if not commercially available, are synthesised in accordance with standard laboratory procedures.

(3) Example Compounds of the Formulae I-M and I-U for Component A

(4) ##STR00283##
Phase sequence: K 174 C. I.

(5) ##STR00284##
Phase sequence: K 131 C. I.

(6) ##STR00285##
Phase sequence: K 86 C. N (75.6 C.) I. n=0.2281 and =78.

(7) ##STR00286##
Phase sequence: K 85 C. N (78 C.) I. n=0.2321 and =73.

(8) ##STR00287##
Phase sequence: K 67 C. N (68.2 C.) I. n=0.2112 and =67.

(9) ##STR00288##
Phase sequence: K 170 C. I.

(10) ##STR00289##
Phase sequence: K 123 C. N (103.4 C.) I. n=0.2391 and =79.

(11) ##STR00290##
Phase sequence: K 72 C. N 89 C. I. n=0.2321 and =76.

(12) ##STR00291##
Phase sequence: K 81 C. N 92 C. I. n=0.2341 and =73.

(13) ##STR00292##
Phase sequence: T.sub.g to be determined K 62 C. N 82.2 C. I. n=0.2183 and =69.

(14) ##STR00293##
Phase sequence: K 100 C. I. n=0.1674 and =43.

Use Examples

Comparative Example 0

(15) A liquid-crystalline substance having the abbreviation PTP(2)TP-6-3 is prepared by the method of Hsu, C. S., Shyu, K. F., Chuang, Y. Y. and Wu, S.-T., Liq. Cryst., 27 (2), (2000), pp. 283-287, and investigated with respect to its physical properties, in particular in the microwave region. The compound has a nematic phase and a clearing point (T(N,I)) of 114.5 C. Further physical properties at 20 C. are: n.sub.e(589.3 nm)=1.8563; n(589.3 nm)=0.3250; .sub.(1 kHz)=4.3; (1 kHz)=1.8 and .sub.1=2.100 mPa.Math.s. The compound is suitable for applications in the microwave region and/or millimeter wave region, in particular for phase shifters.

(16) TABLE-US-00006 TABLE 1a Properties of the compound PTP(2)TP-6-3 at 19 GHz T/ C. .sub.r,|| .sub.r, tan .sub.,r,|| tan .sub.,r, 20 3.35 2.42 0.278 0.0029 0.0061 45.2

Example 0

(17) A binary liquid-crystal mixture M-0, having the composition and properties as indicated in the following table, is prepared.

(18) TABLE-US-00007 Composition Compound No. Abbreviation 1 PTP(2)TP-6-3 23.75 2 MUU-4-N 5.00 100.00 Physical properties T (N, I) = 113 C. n.sub.o (20 C., 589.3 nm) = 1.5407 n (20 C., 589.3 nm) = t.b.d. .sub.|| (20 C., 1 kHz) = 11.1 (20 C., 1 kHz) = 7.8 k.sub.11 (20 C.) = 12.4 pN k.sub.33 (20 C.) = 27.2 pN V.sub.0 (20 C.) = 1.33 V .sub.1 (20 C.) = t.b.d. mPa .Math. s Remark: t.b.d.: to be determined.

(19) This mixture is suitable for applications in the microwave region and/or millimeter wave region, in particular for phase shifters.

(20) TABLE-US-00008 TABLE 1b Properties of mixture M-0 at 19 GHz T/ C. .sub.r,|| .sub.r, tan .sub.,r,|| tan .sub.,r, 20 t.b.d. t.b.d. t.b.d. t.b.d. t.b.d. t.b.d. Remark: t.b.d.: to be determined.

Comparative Example 1

(21) A liquid-crystal mixture CM-1 having the composition and properties as indicated in the following table is prepared.

(22) TABLE-US-00009 Composition Compound No. Abbreviation 1 PTGI(c3)TP-3-4 25.0 2 PTGI(c4)TP-4-4 25.0 3 PTP(c3)TP-6-3 25.0 4 PTP(1, c3)TP-4-4 25.0 100.0 Physical properties T (N, I) = 140 C. n.sub.o (20 C., 589.3 nm) = 1.5407 n (20 C., 589.3 nm) = t.b.d. .sub.|| (20 C., 1 kHz) = 3.5 (20 C., 1 kHz) = 0.8 k.sub.11 (20 C.) = 9.7 pN k.sub.33 (20 C.) = 51.6 pN V.sub.0 (20 C.) = 3.66 V .sub.1 (20 C.) = 2,220 mPa .Math. s

(23) TABLE-US-00010 TABLE 2 Properties of the CM-1 at 19 GHz T/ C. .sub.r,|| .sub.r, tan .sub.,r,|| tan .sub.,r, 20 3.26 2.37 0.273 0.0020 0.0059 46.3

(24) TABLE-US-00011 TABLE 3 Comparison of the properties of the various examples at 19 GHz and 20 C. Example LC .sub.r,|| .sub.r, tan .sub. max. C-0 P2-6-3* 3.35 2.42 0.278 0.0061 45.2 C-0.sup. P2-6-3*.sup. 3.28.sup. 2.41.sup. 0.264.sup. 0.0070.sup. 37.8.sup. 0 M-0 t.b.d. t.b.d. t.b.d. t.b.d. t.b.d. C-1 CM-1 3.26 2.37 0.273 0.0059 46.3 1-1 M-1-1 3.24 2.38 0.266 0.0062 42.7 1-2 M-1-2 3.25 2.41 0.259 0.0074 35.3 C-2 CM-2 3.19 2.41 0.244 0.0143 17.2 2 M-2 3.06 2.37 0.223 0.0114 19.8 3 M-3 2.92 2.34 0.202 0.0116 17.5 4 M-4 3.04 2.37 0.219 0.0119 18.3 5 M-5 3.05 2.37 0.223 0.0121 18.4 6 M-6.sup. 3.11.sup. 2.44.sup. 0.216.sup. 0.0127.sup. 16.9.sup. 7 M-7.sup. 3.11.sup. 2.44.sup. 0.216.sup. 0.0121.sup. 17.8.sup. 8 M-8 3.00 2.36 0.211 0.0140 15.0 9 M-9 3.07 2.38 0.223 0.121 18.5 10 M-10 2.99 2.38 0.205 0.0105 19.6 11 M-11 3.00 2.39 0.203 0.0108 18.8 12 M-12 3.00 2.39 0.205 0.0107 19.3 13 M-13 2.98 2.38 0.202 0.0107 19.0 Notes: *P2-6-3: PTP(2)TP-6-3, LC: liquid crystal, .sup.at 12 GHz and t.b.d.: to be determined.

Example 1-1

(25) A liquid-crystal mixture M-1-1 having the composition and properties as indicated in the following table is prepared.

(26) TABLE-US-00012 Composition Compound No. Abbreviation 1 PTGI(c3)TP-3-4 23.75 2 PTGI(c4)TP-4-4 23.75 3 PTP(c3)TP-6-3 23.75 4 PTP(1,c3)TP-4-4 23.75 5 UMU-6-N 5.00 100.00 Physical properties T(N, I) = 138 C. n.sub.o (20 C., 589.3 nm) = 1.5386 n (20 C., 589.3 nm) = t.b.d. .sub. (20 C., 1 kHz) = 7.0 (20 C., 1 kHz) = 4.0 k.sub.11 (20 C.) = 10.7 pN k.sub.33 (20 C.) = 31.2 pN V.sub.0 (20 C.) = 1.73 V .sub.1 (20 C.) = 3,216 mPa .Math. s Remark: t.b.d.: to be determined.

(27) This mixture is very highly suitable for applications in the microwave region and/or millimeter wave region, in particular for phase shifters.

(28) TABLE-US-00013 TABLE 4a Properties of mixture M-1-1 at 19 GHz T/ C. .sub.r,|| .sub.r, tan .sub.,r,|| tan .sub.,r, 20 3.24 2.38 0.266 0.0021 0.0062 42.7

(29) The use of 5% of a compound of formula I-U (here UMU-6-N) leads to a very strong increase of at low frequency (1 kHz) and consequently to a drastic reduction of the response time for switching the device on (i.e. .sub.on) compared to comparative example 2 (CM-1). At the same time the loss in tunability and the increase of the dielectric loss, which leads to a smaller figure of merit () are rather small and thus tolerable for many applications.

Example 1-2

(30) A liquid-crystal mixture M-1-2 having the composition and properties as indicated in the following table is prepared.

(31) TABLE-US-00014 Composition Compound No. Abbreviation 1 PTGI(c3)TP-3-4 22.25 2 PTGI(c4)TP-4-4 22.25 3 PTP(c3)TP-6-3 22.25 4 PTP(1,c3)TP-4-4 22.25 5 MUU-4-N 10.00 100.00 Physical properties T(N, I) = 132 C. n.sub.o (20 C., 589.3 nm) = 1.5406 n (20 C., 589.3 nm) = t.b.d. .sub. (20 C., 1 kHz) = 11.6.0 (20 C., 1 kHz) = 8.1 k.sub.11 (20 C.) = 12.2 pN k.sub.33 (20 C.) = 14.0 pN V.sub.0 (20 C.) = 1.30 V .sub.1 (20 C.) = 3,152 mPa .Math. s Remark: t.b.d.: to be determined.

(32) This mixture is very highly suitable for applications in the microwave region and/or millimeter wave region, in particular for phase shifters.

(33) TABLE-US-00015 TABLE 4b Properties of mixture M-1-2 at 19 GHz T/ C. .sub.r,|| .sub.r, tan .sub.,r,|| tan .sub.,r, 20 3.25 2.41 0.259 0.0025 0.0074 35.3

(34) The use of 10% of a compound of formula I-M (here MUU-4-N) leads to a very strong increase of at low frequency (1 kHz) and consequently to a drastic reduction of the response time for switching the device on (i.e. .sub.on) compared to comparative example 2 (CM-1). At the same time the loss in tunability and the increase of the dielectric loss, which leads to a smaller figure of merit () are rather small and thus tolerable for many applications.

Comparative Example 2

(35) A liquid-crystal mixture C-2 having the composition and properties as indicated in the following table is prepared.

(36) TABLE-US-00016 Composition Compound No. Abbreviation 1 GGP-3-CL 10.0 2 GGP-5-CL 20.0 3 PPTUI-3-2 20.0 4 PPTUI-3-4 36.0 5 CPGP-5-2 7.0 6 CPGP-5-3 7.0 100.0 Physical properties T(N, I) = 173 C. n.sub.e (20 C., 589.3 nm) = 1.9549 n (20 C., 589.3 nm) = 0.3348 .sub. (20 C., 1 kHz) = 8.1 (20 C., 1 kHz) = 4.6 k.sub.11 (20 C.) = 24.0 pN k.sub.33 (20 C.) = 34.5 pN V.sub.0 (20 C.) = 2.42 V .sub.1 (20 C.) = 746 mPa .Math. s

(37) This mixture is suitable for applications in the microwave region and/or millimeter wave region. It has a value of , which is comparable to that of the mixture of example 1, however, its figure of merit is way smaller than that of said mixture.

(38) TABLE-US-00017 TABLE 5 Properties of mixture C-2 at 19 GHz T/ C. .sub.r,|| .sub.r, tan .sub.,r,|| tan .sub.,r, 20 3.19 2.41 0.245 0.0035 0.0143 17.2

Example 2

(39) A liquid-crystal mixture M-2 having the composition and properties as indicated in the following table is prepared.

(40) TABLE-US-00018 Composition Compound No. Abbreviation 1 UMU-6-N 5.0 2 CC-4-V 10.0 3 PPTUI-3-2 20.0 4 PPTUI-3-4 20.0 5 PPTUI-4-4 31.0 6 CPTP-3-2 3.0 7 CPTP-4-1 3.0 8 CPGP-5-2 4.0 9 CPGP-5-3 4.0 100.0 Physical properties T(N, I) = 157 C. n.sub.e (20 C., 589.3 nm) = 1.8180 n (20 C., 589.3 nm) = 0.3068 .sub. (20 C., 1 kHz) = 7.4 (20 C., 1 kHz) = 4.8 k.sub.11 (20 C.) = 19.2 pN k.sub.33 (20 C.) = 24.3 pN V.sub.0 (20 C.) = 2.10 V .sub.1 (20 C.) = 438 mPa .Math. s

(41) TABLE-US-00019 TABLE 5 Properties of mixture M-2 at 19 GHz T/ C. .sub.r,|| .sub.r, tan .sub.,r,|| tan .sub.,r, 20 3.06 2.37 0.223 0.0031 0.0114 19.8

(42) This mixture, which is using 5% of a compound of formula I-U (i.e. UMU-6-N), is very well suitable for applications in the microwave region and/or millimeter wave region, in particular for phase shifters. It has a at low frequency (1 kHz) of 4.8, which is slightly higher than that of the mixture of comparative example 3 (CM-2) and consequently has an even further reduced response time for switching the device on (i.e. .sub.on) compared to comparative example 3. At the same time it shows a significant decrease of the dielectric loss, which leads to a corresponding larger figure of merit (), while the loss in tuneability is rather small and thus tolerable for most applications.

Example 3

(43) A liquid-crystal mixture M-3 having the composition and properties as indicated in the following table is prepared.

(44) TABLE-US-00020 Composition Compound No. Abbreviation 1 UMU-4-N 5.0 2 UMU-6-N 5.0 3 CC-4-V 20.0 4 PPTUI-3-2 15.0 5 PPTUI-3-4 15.0 6 PPTUI-4-4 26.0 7 CPTP-3-2 3.0 8 CPTP-4-1 3.0 9 CPGP-5-2 4.0 10 CPGP-5-3 4.0 100.0 Physical properties T(N, I) = 139 C. n.sub.e (20 C., 589.3 nm) = 1.7737 n (20 C., 589.3 nm) = 0.2673 .sub. (20 C., 1 kHz) = 12.2 (20 C., 1 kHz) = 9.0 k.sub.11 (20 C.) = 17.6 pN k.sub.33 (20 C.) = 18.6 pN V.sub.0 (20 C.) = 1.48 V .sub.1 (20 C.) = 297 mPa .Math. s

(45) TABLE-US-00021 TABLE 6 Properties of mixture M-3 at 19 GHz T/ C. .sub.r,|| .sub.r, tan .sub.,r,|| tan .sub.,r, 20 2.92 2.34 0.202 0.0032 0.0116 17.5

(46) This mixture, which is using a total of 10% of compounds of formula I-U (i.e. 5% each of UMU-4-N and UMU-6-N), is very well suitable for applications in the microwave region and/or millimeter wave region, in particular for phase shifters. It has a at low frequency (1 kHz) of 9.0, which is almost double the value of the mixture of the mixture of comparative example 3 (CM-2) and consequently has an even further reduced response time for switching the device on (i.e. .sub.on) compared to comparative example 3. At the same time it even shows a significant decrease of the dielectric loss, which leads to a corresponding larger figure of merit (), while the loss in tuneability is still rather small and thus tolerable for most applications.

Example 4

(47) A liquid-crystal mixture M-4 having the composition and properties as indicated in the following table is prepared.

(48) TABLE-US-00022 Composition Compound No. Abbreviation 1 UMU-4-N 5.0 2 UMU-6-N 5.0 3 CC-4-V 6.0 4 PTP-4-5 10.0 5 PPTUI-3-2 10.0 6 PPTUI-3-4 20.0 7 PPTUI-4-4 30.0 8 CPTP-3-2 3.0 9 CPTP-4-1 3.0 10 CPGP-5-2 4.0 11 CPGP-5-3 4.0 100.0 Physical properties T(N, I) = 140.5 C. n.sub.e (20 C., 589.3 nm) = 1.8115 n (20 C., 589.3 nm) = 0.2984 .sub. (20 C., 1 kHz) = 12.6 (20 C., 1 kHz) = 9.4 k.sub.11 (20 C.) = 18.2 pN k.sub.33 (20 C.) = 18.4 pN V.sub.0 (20 C.) = 1.48 V .sub.1 (20 C.) = 431 mPa .Math. s

(49) TABLE-US-00023 TABLE 7 Properties of mixture M-4 at 19 GHz T/ C. .sub.r,|| .sub.r, tan .sub.,r,|| tan .sub.,r, 20 3.04 2.37 0.219 0.032 0.0119 18.3

(50) This mixture, which is also using a total of 10% of compounds of formula I-U, like the mixture of the previous example, example 3, is also very well suitable for applications in the microwave region and/or millimeter wave region, in particular for phase shifters. It has an even increased value of at low frequency (1 kHz) of 9.4 and, otherwise, it shows properties, which are comparable to those of the mixture of example 3.

Example 5

(51) A liquid-crystal mixture M-5 having the composition and properties as indicated in the following table is prepared.

(52) TABLE-US-00024 Composition Compound No. Abbreviation 1 UMU-4-N 5.0 2 UMU-6-N 5.0 3 CC-4-V 10.0 4 PPTUI-3-2 20.0 5 PPTUI-3-4 20.0 6 PPTUI-4-4 26.0 7 CPTP-3-2 3.0 8 CPTP-4-1 3.0 9 CPGP-5-2 4.0 10 CPGP-5-3 4.0 100.0 Physical properties T(N, I) = 154 C. n.sub.e (20 C., 589.3 nm) = 1.8139 n (20 C., 589.3 nm) = 0.3020 .sub. (20 C., 1 kHz) = 12.8 (20 C., 1 kHz) = 9.5 k.sub.11 (20 C.) = 19.0 pN k.sub.33 (20 C.) = 22.0 pN V.sub.0 (20 C.) = 1.49 V .sub.1 (20 C.) = 441 mPa .Math. s

(53) This mixture is very highly suitable for applications in the microwave region and/or millimeter wave region, in particular for phase shifters.

(54) TABLE-US-00025 TABLE 8 Properties of mixture M-5 at 19 GHz T/ C. .sub.r,|| .sub.r, tan .sub.,r,|| tan .sub.,r, 20 3.05 2.37 0.223 0.0033 0.0121 18.4

(55) This mixture, which is also using a total of 10% of compounds of formula I-U, like the mixtures of the two previous examples, examples 3 and 4, is also very well suitable for applications in the microwave region and/or millimeter wave region, in particular for phase shifters. It has an even slightly more increased at low frequency (1 kHz) of 9.5 and, otherwise, it shows properties, which are has comparable to those of the mixture of examples 3 and 4.

Example 6

(56) A liquid-crystal mixture M-6 having the composition and properties as indicated in the following table is prepared.

(57) TABLE-US-00026 Composition Compound No. Abbreviation 1 MUU-4-N 5.0 2 CC-4-V 10.0 3 PPTUI-3-2 20.0 4 PPTUI-3-4 20.0 5 PPTUI-4-4 31.0 6 CPTP-3-2 3.0 7 CPTP-4-1 3.0 8 CPGP-5-2 4.0 9 CPGP-5-3 4.0 100.0 Physical properties T(N, I) = 158.5 C. n.sub.e (20 C., 589.3 nm) = 1.8215 n (20 C., 589.3 nm) = 0.3098 .sub. (20 C., 1 kHz) = 8.0 (20 C., 1 kHz) = 5.1 k.sub.11 (20 C.) = 19.0 pN k.sub.33 (20 C.) = 24.6 pN V.sub.0 (20 C.) = 2.04 V .sub.1 (20 C.) = 458 mPa .Math. s

(58) This mixture is very highly suitable for applications in the microwave region and/or millimeter wave region, in particular for phase shifters.

(59) TABLE-US-00027 TABLE 9 Properties of mixture M-6 at 12 GHz T/ C. .sub.r,|| .sub.r, tan .sub.,r,|| tan .sub.,r, 20 3.11 2.44 0.216 0.0031 0.0121 17.8

(60) This mixture, which is using 5% of a compound of formula I-M with a terminal cyano group, is very well suitable for applications in the microwave region and/or millimeter wave region, in particular for phase shifters.

Example 7

(61) A liquid-crystal mixture M-7 having the composition and properties as indicated in the following table is prepared.

(62) TABLE-US-00028 Composition Compound No. Abbreviation 1 MUU-5-T 5.0 2 CC-4-V 10.0 3 PPTUI-3-2 20.0 4 PPTUI-3-4 20.0 5 PPTUI-4-4 31.0 6 CPTP-3-2 3.0 7 CPTP-4-1 3.0 8 CPGP-5-2 4.0 9 CPGP-5-3 4.0 100.0 Physical properties T(N, I) = 157 C. n.sub.e (20 C., 589.3 nm) = 1.8169 n (20 C., 589.3 nm) = 0.3070 .sub. (20 C., 1 kHz) = 6.1 (20 C., 1 kHz) = 3.3 k.sub.11 (20 C.) = 19.8 pN k.sub.33 (20 C.) = 25.8 pN V.sub.0 (20 C.) = 2.57 V .sub.1 (20 C.) = 445 mPa .Math. s

(63) This mixture is very highly suitable for applications in the microwave region and/or millimeter wave region, in particular for phase shifters.

(64) TABLE-US-00029 TABLE 10 Properties of mixture M-7 at 12 GHz T/ C. .sub.r,|| .sub.r, tan .sub.,r,|| tan .sub.,r, 20 3.11 2.44 0.216 0.0033 0.0127 16.9

(65) This mixture, which is using 5% of a compound of formula I-M with a terminal trifluoromethyl group, is very well suitable for applications in the microwave region and/or millimeter wave region, in particular for phase shifters.

Example 8

(66) A liquid-crystal mixture M-8 having the composition and properties as indicated in the following table is prepared.

(67) TABLE-US-00030 Composition Compound No. Abbreviation 1 UMU-6-N 5.0 2 CC-4-V 12.0 3 PPTUI-3-2 7.0 4 PPTUI-3-4 10.0 5 PPTUI-4-4 30.0 6 GGP-3-CL 9.0 7 GGP-5-CL 17.0 8 CPGP-5-2 5.0 9 CPGP-5-3 5.0 100.0 Physical properties T(N, I) = 141 C. n.sub.e (20 C., 589.3 nm) = 1.7899 n (20 C., 589.3 nm) = 0.2773 .sub. (20 C., 1 kHz) = 11.4 (20 C., 1 kHz) = 7.9 k.sub.11 (20 C.) = 18.8 pN k.sub.33 (20 C.) = 19.8 pN V.sub.0 (20 C.) = 1.63 V .sub.1 (20 C.) = 372 mPa .Math. s

(68) This mixture is very highly suitable for applications in the microwave region and/or millimeter wave region, in particular for phase shifters.

(69) TABLE-US-00031 TABLE 11 Properties of mixture M-8 at 19 GHz T/ C. .sub.r,|| .sub.r, tan .sub.,r,|| tan .sub.,r, 20 3.00 2.37 0.211 0.0038 0.0140 15.0

(70) This mixture, which is using 5% of a compound of formula I-U with a terminal cyano group, is very well suitable for applications in the microwave region and/or millimeter wave region, in particular for phase shifters.

Example 9

(71) A liquid-crystal mixture M-9 having the composition and properties as indicated in the following table is prepared.

(72) TABLE-US-00032 Composition Compound No. Abbreviation 1 UMU-6-N 5.0 2 CC-4-V 10.0 3 PPTUI-3-2 20.0 4 PPTUI-3-4 20.0 5 PPTUI-4-4 31.0 6 GGP-3-CL 3.0 7 GGP-5-CL 3.0 8 CPGP-5-2 4.0 9 CPGP-5-3 4.0 100.0 Physical properties T(N, I) = 153 C. n.sub.e (20 C., 589.3 nm) = 1.8236 n (20 C., 589.3 nm) = 0.3105 .sub. (20 C., 1 kHz) = 8.7 (20 C., 1 kHz) = 5.7 k.sub.11 (20 C.) = 18.6 pN k.sub.33 (20 C.) = 24.1 pN V.sub.0 (20 C.) = 1.92 V .sub.1 (20 C.) = 422 mPa .Math. s

(73) This mixture is very highly suitable for applications in the microwave region and/or millimeter wave region, in particular for phase shifters.

(74) TABLE-US-00033 TABLE 12 Properties of mixture M-9 at 19 GHz T/ C. .sub.r,|| .sub.r, tan .sub.,r,|| tan .sub.,r, 20 3.07 2.38 0.223 0.0032 0.0121 18.5

(75) This mixture, which is using 5% of a compound of formula I-U, is very well suitable for applications in the microwave region and/or millimeter wave region, in particular for phase shifters.

Example 10

(76) A liquid-crystal mixture M-10 having the composition and properties as indicated in the following table is prepared.

(77) TABLE-US-00034 Composition Compound No. Abbreviation 1 UMU-6-N 4.0 2 CC-4-V 8.0 3 PPTUI-3-2 10.0 4 PPTUI-3-4 16.0 5 PPTUI-4-4 30.0 6 PTP-3-5 16.0 7 PTP-4-5 16.0 100.0 Physical properties T(N, I) = 94 C. n.sub.o (20 C., 589.3 nm) = 1.5144 n (20 C., 589.3 nm) = t.b.d. .sub. (20 C., 1 kHz) = 6.4 (20 C., 1 kHz) = 3.5 k.sub.11 (20 C.) = 12.4 pN k.sub.33 (20 C.) = 19.0 pN V.sub.0 (20 C.) = 1.98 V .sub.1 (20 C.) = 234 mPa .Math. s Remaks. t.b.d.: to be determined.

(78) This mixture is very highly suitable for applications in the microwave region and/or millimeter wave region, in particular for phase shifters.

(79) TABLE-US-00035 TABLE 13 Properties of mixture M-10 at 19 GHz T/ C. .sub.r,|| .sub.r, tan .sub.,r,|| tan .sub.,r, 20 2.99 2.38 0.205 0.0032 0.0105 19.6

(80) This mixture, which is using 4% of a compound of formula I-U, is very well suitable for applications in the microwave region and/or millimeter wave region, in particular for phase shifters.

Example 11

(81) A liquid-crystal mixture M-11 having the composition and properties as indicated in the following table is prepared.

(82) TABLE-US-00036 Composition Compound No. Abbreviation 1 UMU-6-N 4.0 2 CC-3-V 8.0 3 PPTUI-3-2 10.0 4 PPTUI-3-4 16.0 5 PPTUI-4-4 30.0 6 PTP-3-5 16.0 7 PTP-4-5 16.0 100.0 Physical properties T(N, I) = 95 C. n.sub.o (20 C., 589.3 nm) = 1.5138 n (20 C., 589.3 nm) = t.b.d. .sub. (20 C., 1 kHz) = 6.3 (20 C., 1 kHz) = 3.5 k.sub.11 (20 C.) = 12.7 pN k.sub.33 (20 C.) = 19.0 pN V.sub.0 (20 C.) = 2.01 V .sub.1 (20 C.) = 227 mPa .Math. s Remaks. t.b.d.: to be determined.

(83) This mixture is very highly suitable for applications in the microwave region and/or millimeter wave region, in particular for phase shifters.

(84) TABLE-US-00037 TABLE 14 Properties of mixture M-11 at 19 GHz T/ C. .sub.r,|| .sub.r, tan .sub.,r,|| tan .sub.,r, 20 3.00 2.39 0.203 0.0034 0.0108 18.8

(85) This mixture, which is using 4% of a compound of formula I-U, is very well suitable for applications in the microwave region and/or millimeter wave region, in particular for phase shifters.

Example 12

(86) A liquid-crystal mixture M-12 having the composition and properties as indicated in the following table is prepared.

(87) TABLE-US-00038 Composition Compound No. Abbreviation 1 UMU-6-N 4.0 2 CC-4-V 10.0 3 PPTUI-3-2 10.0 4 PPTUI-3-4 18.0 5 PPTUI-4-4 30.0 6 PTP-3-5 14.0 7 PTP-4-5 14.0 100.0 Physical properties T(N, I) = 98 C. n.sub.o (20 C., 589.3 nm) = 1.7878 n (20 C., 589.3 nm) = 0.2750 .sub. (20 C., 1 kHz) = 6.4 (20 C., 1 kHz) = 3.5 k.sub.11 (20 C.) = 13.1 pN k.sub.33 (20 C.) = 19.5 pN V.sub.0 (20 C.) = 2.03 V .sub.1 (20 C.) = 228 mPa .Math. s

(88) This mixture is very highly suitable for applications in the microwave region and/or millimeter wave region, in particular for phase shifters.

(89) TABLE-US-00039 TABLE 15 Properties of mixture M-12 at 19 GHz T/ C. .sub.r,|| .sub.r, tan .sub.,r,|| tan .sub.,r, 20 3.00 2.38 0.205 0.0033 0.0107 19.3

(90) This mixture, which is using 4% of a compound of formula I-U, is very well suitable for applications in the microwave region and/or millimeter wave region, in particular for phase shifters.

Example 13

(91) A liquid-crystal mixture M-13 having the composition and properties as indicated in the following table is prepared.

(92) TABLE-US-00040 Composition Compound No. Abbreviation 1 UMU-6-N 4.0 2 CC-4-V 6.0 3 PPTUI-3-4 20.0 4 PPTUI-4-4 20.0 5 PTP-3-5 20.0 6 PTP-4-5 20.0 100.0 Physical properties T(N, I) = 85 C. n.sub.o (20 C., 589.3 nm) = 1.5153 n (20 C., 589.3 nm) = t.b.d. .sub. (20 C., 1 kHz) = 6.2 (20 C., 1 kHz) = 3.4 k.sub.11 (20 C.) = 11.8 pN k.sub.33 (20 C.) = 18.2 pN V.sub.0 (20 C.) = 1.99 V .sub.1 (20 C.) = 216 mPa .Math. s Remaks. t.b.d.: to be determined.

(93) This mixture is very highly suitable for applications in the microwave region and/or millimeter wave region, in particular for phase shifters.

(94) TABLE-US-00041 TABLE 16 Properties of mixture M-13 at 19 GHz T/ C. .sub.r,|| .sub.r, tan .sub.,r,|| tan .sub.,r, 20 2.98 2.38 0.202 0.0033 0.0107 19.0

(95) This mixture, which is using 4% of a compound of formula I-U, is very well suitable for applications in the microwave region and/or millimeter wave region, in particular for phase shifters.