LIQUID-CRYSTAL MEDIUM

Abstract

The present invention relates to components for high-frequency technology, especially microwave components for high-frequency devices, such as devices for shifting the phase of microwaves, tunable filters, tunable metamaterial structures and electronic beam steering antennas (e.g. phased array antennas) comprising a liquid-crystalline medium, and to the liquid-crystalline medium used therein, wherein the liquid crystal medium comprises one or more compounds of formula S

##STR00001##

as defined in claim 1.

Claims

1. A Liquid-crystal medium, characterised in that the medium comprises one or more compounds of formula S ##STR00369## in which R.sup.S denotes H, alkyl or alkoxy having 1 to 12 C atoms, or alkenyl, alkenyloxy or alkoxyalkyl having 2 to 12 C atoms, in which one or more CH.sub.2-groups may be replaced by ##STR00370##  and in which one or more H atoms may be replaced by F, ##STR00371## on each occurrence, independently of one another, denote ##STR00372## in which R.sup.L, on each occurrence identically or differently, denotes H, Cl or alkyl having 1 to 6 C atoms, ##STR00373## alternatively denotes ##STR00374## L.sup.S1, L.sup.S2 identically or differently, denote H, Cl or F, R.sup.S1, R.sup.S2, identically or differently, denote H, alkyl or alkenyl, having up to 6 C atoms, or cyclopropyl, cyclobutyl, cyclopentenyl, or cyclopentyl, R.sup.Th1, R.sup.Th2 identically or differently, denote H, alkyl or alkenyl or alkoxy, having up to 6 C atoms, or cyclopropyl, cyclobutyl, cyclopentenyl or cyclopentyl, Z.sup.S1, Z.sup.S2, Z.sup.S3 identically or differently, denote —CH═CH—, —CH═CF—, —CF═CH—, —CF═CF—, —C≡C—, or a single bond, a, b identically or differently, are 0 or 1, and one or more compounds of formula IC ##STR00375## in which R.sup.1 denotes H, alkyl or alkoxy having 1 to 15 C atoms, or alkenyl, alkenyloxy or alkoxyalkyl having 2 to 15 C atoms, in which one or more CH.sub.2-groups may be replaced by ##STR00376## ##STR00377## on each occurrence, independently of one another, denote ##STR00378## in which R.sup.L, on each occurrence identically or differently, denotes H or alkyl having 1 to 6 C atoms.

2. The medium according to claim 1, wherein the medium has a clearing temperature of 120° C. or more.

3. The medium according to claim 1, wherein the medium comprises one or more compounds selected from the group of compounds of the formulae S1 to S24 ##STR00379## ##STR00380## ##STR00381## in which R.sup.S, R.sup.Th1, R.sup.Th2, L.sup.S1 and L.sup.S2 have the meanings indicated in claim 1 for formula S and R.sup.S3 denotes H, F or alkyl, having up to 6 C atoms, or cyclopropyl.

4. The medium according to claim 1, wherein the medium comprises a compound of formula S in which at least one of the groups Z.sup.S1, Z.sup.S2 and Z.sup.S3 denotes —C≡C—.

5. The liquid-crystal medium according to claim 1, wherein the medium further comprises one or more compounds selected from the group of compounds of formulae I, II and III ##STR00382## in which R.sup.1 denotes H, alkyl or alkoxy having 1 to 15 C atoms, or alkenyl, alkenyloxy or alkoxyalkyl having 2 to 15 C atoms, in which one or more CH.sub.2-groups may be replaced by ##STR00383## n is 0, 1 or 2, ##STR00384## on each occurrence, independently of one another, denote ##STR00385## in which R.sup.L, on each occurrence identically or differently, denotes H or alkyl having 1 to 6 C atoms, and wherein ##STR00386## alternatively denotes ##STR00387## R.sup.2 denotes H, alkyl or alkoxy having 1 to 15 C atoms, or alkenyl, alkenyloxy or alkoxyalkyl having 2 to 15 C atoms, in which one or more CH.sub.2-groups may be replaced by ##STR00388## Z.sup.21 denotes trans-CH═CH—, trans-CF═CF— or —C≡C—, and ##STR00389## independently of one another, denote ##STR00390## in which R.sup.L, on each occurrence identically or differently, denotes H or alkyl having 1 to 6 C atoms, R.sup.3 denotes H, alkyl or alkoxy having 1 to 15 C atoms, or alkenyl, alkenyloxy or alkoxyalkyl having 2 to 15 C atoms, in which one or more CH.sub.2-groups may be replaced by ##STR00391## one of Z.sup.31 and Z.sup.32, denotes trans-CH═CH—, trans-CF═CF— or —C≡C— and the other one, independently thereof, denotes —C≡C—, trans-CH═CH—, trans-CF═CF— or a single bond, and ##STR00392## independently of one another, denote ##STR00393## in which R.sup.L, on each occurrence identically or differently, denotes H or alkyl having 1 to 6 C atoms, and wherein ##STR00394## alternatively denotes ##STR00395##

6. The liquid-crystal medium according to claim 1, wherein the medium further comprises one or more compounds of formula IIIC ##STR00396## in which R.sup.C denotes H, alkyl or alkoxy having 1 to 12 C atoms, or alkenyl, alkenyloxy or alkoxyalkyl having 2 to 12 C atoms, in which one or more CH.sub.2-groups may be replaced by ##STR00397## L.sup.C1, L.sup.C2 identically or differently, denote H, Cl or F, R.sup.C1, R.sup.C2 identically or differently, denote H or alkyl having 1 to 6 C atoms, or cyclopropyl, cyclobutyl or cyclopentyl, R.sup.C3, R.sup.C4, R.sup.C5 and R.sup.C6 identically or differently, denote H, Cl, F or alkyl having 1 to 6 C atoms, or cyclopropyl, cyclobutyl or cyclopentyl.

7. The liquid-crystal medium according to claim 1, wherein the medium further comprises one or more compounds of formula T ##STR00398## in which R.sup.T denotes halogen, CN, NCS, R.sup.F, R.sup.F—O— or R.sup.F—S—, wherein R.sup.F denotes fluorinated alkyl or fluorinated alkenyl having up to 12 C atoms, ##STR00399## on each occurrence, independently of one another, denote ##STR00400## L.sup.1 and L.sup.2 identically or differently, denote Cl, F, alkyl having 1 to 6 C atoms or cyclopropyl, cyclobutyl or cyclopentyl, and t is 0, 1 or 2.

8. The liquid-crystal medium according to claim 5, wherein the medium comprises one or more compounds selected from the group of compounds of formulae I-1 to I-4 ##STR00401## in which L.sup.1, L.sup.2 and L.sup.3 on each occurrence, identically or differently, denote H or F, and R.sup.1, ##STR00402## have the meanings given for formula I in claim 5.

9. The liquid-crystal medium according to claim 5, wherein the medium comprises one or more compounds selected from the group of compounds of the formulae II-1 to II-3 ##STR00403## in which R.sup.2, ##STR00404## have the meanings given in claim 5 for formula II.

10. The liquid-crystal medium according to claim 5, wherein the medium comprises one or more compounds selected from the group of compounds of the formulae III-1 to III-6 ##STR00405## in which R.sup.3, ##STR00406## have the meanings given in claim 5 for formula III, and Z.sup.31 and Z.sup.32 independently of one another, denote trans-CH═CH— or trans-CF═CF—, and in formula III-6 alternatively one of Z.sup.31 and Z.sup.32 denotes —C≡C—.

11. The liquid-crystal medium according to claim 1, wherein the medium further comprises one or more chiral compounds.

12. A compound of formula S ##STR00407## in which R.sup.S denotes H, alkyl or alkoxy having 1 to 12 C atoms, or alkenyl, alkenyloxy or alkoxyalkyl having 2 to 12 C atoms, in which one or more CH.sub.2-groups may be replaced by ##STR00408##  and in which one or more H atoms may be replaced by F, ##STR00409## on each occurrence, independently of one another, denote ##STR00410## in which R.sup.L, on each occurrence identically or differently, denotes H, Cl or alkyl having 1 to 6 C atoms, ##STR00411## alternatively denotes ##STR00412## L.sup.S1, L.sup.S2 identically or differently, denote H, Cl or F, R.sup.S1, R.sup.S2, identically or differently, denote H or alkyl having 1 to 6 C atoms, or cyclopropyl, cyclobutyl or cyclopentyl, R.sup.Th1, R.sup.Th2 identically or differently, denote H, alkyl, alkenyl or alkoxy having up to 6 C atoms, Z.sup.S1, Z.sup.S2, Z.sup.S3 identically or differently, denote —CH═CH—, —CH═CF—, —CF═CH—, —CF═CF—, or a single bond, a, b identically or differently, are 0 or 1, with the proviso that the compounds of the following formula S* are excluded: ##STR00413## in which R.sup.S denotes alkyl, alkenyl or alkoxy having up to 9 C atoms, Z.sup.S2 denotes —CH═CH—, —CH═CF—, —CF═CH—, —CF═CF—, or a single bond, R.sup.S1, R.sup.S2 identically or differently, denote H or F, and L.sup.S1, L.sup.S2 identically or differently, denote H or F.

13. Use of a compound of formula S according to claim 12 in a component for high-frequency technology.

14. Component for high-frequency technology comprising a liquid-crystal medium according to claim 1.

15. Component according to claim 14, wherein the component is a liquid-crystal based antenna element, a phase shifter, a tunable filter, a tunable metamaterial structure, a matching network or a varactor.

16. Microwave antenna array comprising one or more components according to claim 14.

17. Process for the preparation of a liquid-crystal medium according to claim 5, comprising mixing one or more compounds of formula S with one or more compounds of formula I and/or II and/or III, and optionally additional mesogenic compounds and optionally a chiral compound.

18. A component for high-frequency technology comprising a compound of formula S according to claim 12.

19. A component according to claim 18, wherein the component is a liquid-crystal based antenna element, a phase shifter, a tunable filter, a tunable metamaterial structure, a matching network or a varactor.

20. A microwave antenna array comprising one or more components according to claim 18.

21. A process for the preparation 1 n of a liquid-crystal medium according to claim 1, comprising mixing one or more compounds of formula S with one or more compounds of one or more compounds of formula IC and optionally additional mesogenic compounds and optionally a chiral compound.

Description

EXAMPLES

[0664] The following examples illustrate the present invention without limiting it in any way.

[0665] However, it is 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.

Mixture Examples

[0666] Liquid-crystal host mixture H1 having the compositions and properties as indicated in the following tables are prepared and characterized with respect to their general physical properties and their applicability in microwave components at 19 GHz and 20° C.

[0667] Mixture H1

TABLE-US-00007 BCH-3F.F  12.0% T(N, I) = 92° C. BCH-5F.F  10.0% Δn (20° C., 589.3 nm) = 0.0969 ECCP-30CF3  5.0% Δϵ (20° C., 1 kHz) = 5.2 ECCP-50CF3  5.0% CBC-33F  2.0% CBC-53F  2.0% CBC-55F  2.0% PCH-6F  8.0% PCH-7F  6.0% CCP-20CF3  8.0% CCP-30CF3  12.0% CCP-40CF3  7.0% CCP-50CF3  11.0% PCH-5F  10.0% Σ 100.0%

[0668] A nematic liquid-crystal medium N1 consisting of 90% of the medium H1 and 10% of the compound of Synthesis Example 1 (compound (1)) has the following properties:

TABLE-US-00008 N1  90.0% T(N, I) = 93 ° C. (1)  10.0% Δn (20° C., 589.3 nm) = 0.1341 Σ 100.0% Δϵ (20° C., 1 kHz) = 6.7

[0669] The compound (1) is well soluble in the medium H1. The addition of the compound (1) to the medium H1 has no negative influence in the properties of the host H1.

[0670] The addition of the compound (1) to the medium H1 has the effect that the material quality η is significantly improved due to a higher tunability (τ) and lower dielectric loss (tan δ.sub.εr,⊥) of the medium, as shown in the following table.

TABLE-US-00009 ε.sub.r,.sub.|| tan δ.sub.ε.sub.r,|| ε.sub.r,⊥ tan δ.sub.ε.sub.r,⊥ τ η H1 2.4873 0.0045 2.2327 0.0123 0.1024  8.3 N1 2.6315 0.0049 2.2902 0.0121 0.1297 10.7

[0671] Further mixtures are prepared and charactersied as follows:

[0672] Mixture N2

TABLE-US-00010 PTU-3-S  10.0% T.sub.(N, I). [° C.]: 140.0 PTU-5-S  8.0% Δn (589.3 nm, 20° C.): 0.3777 PGU-3-S  18.0% Δϵ (1 kHz, 20° C.): 21.8 PPTU-4-S  7.0% PPTU-5-S  9.0% PGTU-4-S  6.0% CPU-2-S  22.0% CPU-4-S  10.0% ThTU-5-S  10.0% Σ 100.0%

[0673] Mixture N3

TABLE-US-00011 PTU-3-S  8.0% T.sub.(N, I). [° C.]: 148.5 PG U-3-S  18.0% Δn (589.3 nm, 20° C.): 0.3801 PPTU-4-S  7.0% Δϵ (1 kHz, 20° C.): 21.1 PPTU-5-S  9.0% PGTU-4-S  6.0% CPU-2-S  22.0% CPU-4-S  10.0% ThTU-5-S  10.0% ThU-5-S  10.0% Σ 100.0%

[0674] Mixture N4

TABLE-US-00012 PGU-3-S  18.0% T.sub.(N, I). [° C.]: 151.0 PPTU-4-S  7.0% Δn (589.3 nm, 20° C.): 0.3900 PPTU-5-S  9.0% ΔE (1 kHz, 20° C.): 21.1 PGTU-4-S  6.0% CPU-2-S  22.0% CPU-4-S  6.0% ThTU-5-S  16.0% ThU-5-S  16.0% Σ 100.0%