LIQUID-CRYSTALLINE MEDIUM

Abstract

The present invention relates to liquid-crystalline media comprising one or more compounds of formula Q

##STR00001##

and one or more compounds selected from the group of compounds of formulae T, U and I

##STR00002##

wherein the occurring groups and parameters have the meaning indicated in claim 1. The present invention further 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 millimetre wave region, for microwave and millimetre wave array antennae and very particularly for so-called tunable reflectarrays.

Claims

1. Liquid-crystal medium, characterised in that it comprises one or more compounds of formula Q ##STR00268## and one or more compounds selected from the group of compounds of formulae T, U and I ##STR00269## wherein R.sup.1 denotes alkyl, which is straight chain or branched having 1 to 15 C-atoms, is unsubstituted, mono- or poly-substituted by F, Cl or CN, preferably by F, and in which one or more CH.sub.2 groups are optionally replaced, in each case independently from one another, by O, S, CR.sup.01R.sup.02, SiR.sup.01R.sup.02, CO, COO, OCO, OCOO, SCO, COS, CY.sup.01CY.sup.02 or CC in such a way that O and/or S atoms are not linked directly to one another; Y.sup.01 and Y.sup.02 are, independently of each other, F, Cl or CN, and alternatively one of them may be H, R.sup.01 and R.sup.02 are, independently of each other, H or alkyl with 1 to 12 C-atoms, L.sup.1, L.sup.2 and L.sup.3 each, independently from one another, denote H or F; R.sup.03 and R.sup.04 independently from one another, have the meaning given for R.sup.1 above, ##STR00270## independently of one another, denote ##STR00271## wherein Y denotes S or O, and wherein in the 1,4-phenylene groups, one or more CH groups may be replaced by N, and L.sup.0 on each occurrence, independently of one another, denotes H, Br, Cl, F, CN, NCS, SCN, SF.sub.5, C.sub.1-C.sub.10 alkyl, C.sub.1-C.sub.10 alkoxy, C.sub.3-C.sub.6 cycloalkyl or a mono- or polyfluorinated C.sub.1-C.sub.10 alkyl or alkoxy group, R.sup.05 and R.sup.06 each, independently of one another, denote a halogenated or unsubstituted alkyl radical having 1 to 6 C atoms, where, one or more CH.sub.2 groups in these radicals may each be replaced, independently of one another by CC, CHCH, CFCF, CFCH, CHCF, (CO)O, O(CO), (CO), O or S in such a way that O or S atoms are not linked directly to one another, 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 from 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, one of Z.sup.61 and Z.sup.62 denotes trans-CHCH, trans-CFCF or CC and the other denotes trans-CHCH, trans-CFCF or a single bond, and ##STR00272## independently of one another, denote ##STR00273## R.sup.11 and R.sup.12, 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; ##STR00274## denotes ##STR00275## L.sup.11 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.11 denotes H, alkyl having 1 to 3 C atoms or halogen, R.sup.13 and R.sup.14, independently of one another, have the meaning given for R.sup.11 and R.sup.12, and alternatively one of R.sup.13 and R.sup.14 or both also denote H.

2. Liquid crystal medium according to claim 1, characterised in that it comprises one or more compounds selected from the group of compounds of formulae Q-1 to Q-5 ##STR00276## wherein R.sup.1 has the meaning indicated for formula Q.

3. Liquid-crystal medium according to claim 1, characterised in that it comprises one or more compounds of formula T.

4. Liquid-crystal medium according to claim 1, characterised in that it comprises one or more compounds of formula U.

5. Liquid-crystal medium according to claim 1, characterised in that it comprises one or more compounds of formula I.

6. Liquid-crystal medium according to claim 1, characterised in that one or more compounds of formula T are selected from the group of compounds of the sub-formulae T-1 to T-7 ##STR00277## wherein R.sup.03 and R.sup.04 have the meaning indicated for formula T.

7. Liquid-crystal medium according to claim 1, characterised in that one or more compounds of formula U are selected from the group of compounds of the formulae ##STR00278## wherein the occurring groups have the meaning indicated for formula U.

8. Liquid-crystal medium according to claim 1, characterised in that it comprises one or more compounds of formula U, wherein X.sup.62 denotes NCS.

9. Liquid crystal medium according to claim 1, characterised in that it additionally comprises one or more compounds of formula V ##STR00279## in which L.sup.51 denotes R.sup.51 or X.sup.51, L.sup.52 denotes R.sup.52 or X.sup.52, R.sup.51 and R.sup.52, 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.51 and X.sup.52, independently of one another, denote H, F, Cl, CN, NCS, SF.sub.5, fluorinated alkyl or fluorinated alkoxy having 1 to 7 C atoms or fluorinated alkenyl, fluorinated alkenyloxy or fluorinated alkoxyalkyl having 2 to 7 C atoms, and ##STR00280## independently of one another, denote ##STR00281##

10. Liquid crystal medium according to claim 1, characterised in that it additionally comprises one or more compounds of formula V, selected from the group of compounds of the sub-formulae V-2a to V2-g ##STR00282## where in each case the compounds of the formula V-2a are excluded from the compounds of the formulae V-2b and V-2c, the compounds of the formula V-2b are excluded from the compounds of the formula V-2c and the compounds of the formula V-2e are excluded from the compounds of the formula V-2f, and R.sup.51 denotes unfluorinated alkyl having 1 to 7 C atoms or unfluorinated alkenyl having 2 to 7 C atoms, R.sup.52 denotes unfluorinated alkyl having 1 to 7 C atoms or unfluorinated alkenyl having 2 to 7 C atoms or unfluorinated alkoxy having 1 to 7 C atoms, Y.sup.51 and Y.sup.52, in each case independently from one another, denote H or F.

11. Process for the preparation of a liquid-crystal medium according to claim 1, characterised in that one or more compounds of formula Q and one or more compounds of formula T and/or U and/or I are mixed with one another and optionally with one or more further compounds and/or with one or more additives.

12. (canceled)

13. Component for high-frequency technology, characterised in that it contains a liquid-crystal medium according to claim 1.

14. Microwave antenna array, characterised in that it comprises one or more components for high-frequency technology according to claim 13.

15. Compound of formula Q ##STR00283## wherein R.sup.1 denotes alkyl, which is straight chain or branched having 1 to 15 C-atoms, is unsubstituted, mono- or poly-substituted by F, Cl or CN, preferably by F, and in which one or more CH.sub.2 groups are optionally replaced, in each case independently from one another, by O, S, CR.sup.01R.sup.02, SiR.sup.01R.sup.02, CO, COO, OCO, OCOO, SCO, COS, CY.sup.01CY.sup.02 or CC in such a way that O and/or S atoms are not linked directly to one another; Y.sup.01 and Y.sup.02 are, independently of each other, F, Cl or CN, and alternatively one of them may be H, R.sup.01 and R.sup.02 are, independently of each other, H or alkyl with 1 to 12 C-atoms, L.sup.1, L.sup.2 and L.sup.3 each, independently from one another, denote H or F; with the proviso that one or both of the radicals L.sup.2 and L.sup.3 denotes H.

Description

EXAMPLES

[0390] 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.

USE EXAMPLES

Comparative Example 1

[0391] A liquid-crystal mixture C-1, having the composition and properties as indicated in the following table, is prepared.

TABLE-US-00006 Composition Compound No. Abbreviation c [%] 1 PPTUI-3-4 25.1 2 PPTUI-4-4 48.5 3 PPTUI-3-2 26.4 100.0 Physical properties T(N, I) = 164 C. n.sub.o (20 C., 589.3 nm) = 1.4745 n (20 C., 589.3 nm) = 0.3984 .sub. (20 C., 1 kHz) = 3.9 (20 C., 1 kHz) = 1.2 k.sub.11 (20 C.) = 17.4 pN k.sub.33 (20 C.) = 38.8 pN V.sub.0 (20 C.) = 4.06 V .sub.1 (20 C.) = 697 mPa .Math. s

[0392] This mixture is suitable for applications in the microwave region and/or millimetre wave region, in particular for phase shifters.

Mixture Example 1

[0393] A liquid-crystal mixture M-1, having the composition and properties as indicated in the following table, is prepared.

TABLE-US-00007 Composition Compound No. Abbreviation c [%] 1 PPTUI-3-4 10.0 2 PPTUI-4-4 20.0 3 PPTUI-3-2 25.0 4 PTPI(1)-4-A1 30.0 5 PTP-3-5 6.0 6 PTP-4-5 6.0 7 GUUQU-3-N 3.0 100.0 Physical properties T(N, I) = 97 C. n.sub.o (20 C., 589.3 nm) = N/A n (20 C., 589.3 nm) = N/A .sub. (20 C., 1 kHz) = 5.5 (20 C., 1 kHz) = 2.7 k.sub.11 (20 C.) = 10.8 pN k.sub.33 (20 C.) = 24.7 pN V.sub.0 (20 C.) = 2.11 V .sub.1 (20 C.) = 450 mPa .Math. s

[0394] A liquid-crystal mixture M-2, having the composition and properties as indicated in the following table, is prepared.

TABLE-US-00008 Composition Compound No. Abbreviation c [%] 1 PPTUI-3-4 10.0 2 PPTUI-4-4 20.0 3 PPTUI-3-2 20.0 4 PTPI(1)-4-A1 35.0 5 GUUQU-3-N 4.0 6 PGP-2-3 6.0 7 PGP-2-5 5.0 100.0 Physical properties T(N, I) = 109 C. n.sub.o (20 C., 589.3 nm) = N/A n (20 C., 589.3 nm) = N/A .sub. (20 C., 1 kHz) = 6.4 (20 C., 1 kHz) = 3.4 k.sub.11 (20 C.) = 11.6 pN k.sub.33 (20 C.) = 26.6 pN V.sub.0 (20 C.) = 1.96 V .sub.1 (20 C.) = 555 mPa .Math. s

[0395] A liquid-crystal mixture M-3, having the composition and properties as indicated in the following table, is prepared.

TABLE-US-00009 Composition Compound No. Abbreviation c [%] 1 PPTUI-3-4 10.0 2 PPTUI-4-4 20.0 3 PPTUI-3-2 25.0 4 PTPI(1)-4-A1 30.0 5 PTP-3-5 6.0 6 PTP-4-5 6.0 7 GUUQU-3-N 3.0 100.00 Physical properties T(N, I) = 96 C. n.sub.o (20 C., 589.3 nm) = N/A n (20 C., 589.3 nm) = N/A .sub. (20 C., 1 kHz) = 6.2 (20 C., 1 kHz) = 3.3 k.sub.11 (20 C.) = 10.2 pN k.sub.33 (20 C.) = 25.0 pN V.sub.0 (20 C.) = 1.85 V .sub.1 (20 C.) = 456 mPa .Math. s

[0396] A liquid-crystal mixture M-4, having the composition and properties as indicated in the following table, is prepared.

TABLE-US-00010 Composition Compound No. Abbreviation c [%] 1 PPTUI-3-4 10.0 2 PPTUI-4-4 20.0 3 PPTUI-3-2 25.0 4 PTPI(1)-4-A1 30.0 5 PTP-3-5 6.0 6 PTP-4-5 6.0 7 GGGQU-3-N 3.0 100.00 Physical properties T(N, I) = N/A C. n.sub.o (20 C., 589.3 nm) = N/A n (20 C., 589.3 nm) = N/A .sub. (20 C., 1 kHz) = N/A (20 C., 1 kHz) = N/A k.sub.11 (20 C.) = N/A pN k.sub.33 (20 C.) = N/A pN V.sub.0 (20 C.) = N/A V .sub.1 (20 C.) = N/A mPa .Math. s

[0397] A liquid-crystal mixture M-5, having the composition and properties as indicated in the following table, is prepared.

TABLE-US-00011 Composition Compound No. Abbreviation c [%] 1 PPTUI-3-4 10.0 2 PPTUI-4-4 20.0 3 PPTUI-3-2 25.0 4 PTPI(1)-4-A1 30.0 5 PTP-3-5 6.0 6 PTP-4-5 6.0 7 GGUQU-3-N 3.0 100.00 Physical properties T(N, I) = N/A C. n.sub.o (20 C., 589.3 nm) = N/A n (20 C., 589.3 nm) = N/A .sub. (20 C., 1 kHz) = N/A (20 C., 1 kHz) = N/A k.sub.11 (20 C.) = N/A pN k.sub.33 (20 C.) = N/A pN V.sub.0 (20 C.) = N/A V .sub.1 (20 C.) = N/A mPa .Math. s

Comparison of the Properties of the Various Examples at 19 GHz and 20 C.

[0398]

TABLE-US-00012 Example LC mixture tan .sub. max. comparative C-1 0.2516 0.0118 21.3 example 1 1 M-1 0.2358 0.0096 24.6 2 M-2 0.2451 0.0097 25.3 3 M-3 0.2411 0.0093 25.8 4 M-4 N/A N/A N/A 5 M-5 N/A N/A N/A

[0399] The use of an amount of 3 to 4% of a compound of formula Q (GUUQU-3-N, GGGQU-3-N and GGUQU-3-N in the examples) 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 1 (C-1).

[0400] The use of a compound of formula Q in combination with one or more compounds selected from the group of compounds of formulae T, U and I results in a significant increase of the material quality () due to a decrease of the dielectric loss while the tunability is on a very similar high level compared to comparative example 1 (C-1).