Liquid-crystalline medium and high-frequency components comprising same

Abstract

The present invention relates to liquid-crystalline media comprising one or more chiral compounds and one or more compounds selected from the group of compounds of formulae I, II and III, ##STR00001##
in which the parameters have the meaning indicated in claim 1, and to components comprising these media for high-frequency technology, in particular phase shifters and microwave array antennas.

Claims

1. Liquid-crystal medium, which comprises one or more chiral compounds in an amount sufficient to improve switching times of the liquid crystal medium and within the range of 0.2% to 0.8% by weight based on the total weight of the liquid-crystal medium and one or more compounds of formula I-2d ##STR00273## in which R.sup.1 denotes alkyl having 1-to 7 carbon atoms, one or more compounds of formulae III-1 ##STR00274## and one or more additional compounds of formulae I, II, and III; ##STR00275## in which R.sup.1 denotes 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, n denotes 1, and ##STR00276## independently of one another, denote ##STR00277## alternatively denotes ##STR00278## in which R.sup.2 denotes 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, Z.sup.21 denotes trans-CH═CH—, trans-CF═CF— or —C≡C—, and ##STR00279## independently of one another, denote ##STR00280## in which R.sup.3 denotes 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, 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 trans CH═CH—, trans-CF═CF— or a single bond, and ##STR00281## independently of one another, denote ##STR00282## alternatively independently denotes ##STR00283## and optionally one or more polymerisable compounds of formula P
P.sup.a-(Sp.sup.a).sub.s1-(A.sup.1-Z.sup.1).sub.n1-A.sup.2-Q-A.sup.3-(Z.sup.4-A.sup.4).sub.n2-(Sp.sup.b).sub.s2-P.sup.b  P wherein the individual radicals have the following meanings: P.sup.a P.sup.b each, independently of one another, are a polymerisable group, Sp.sup.a, Sp.sup.b each, independently of one another, denote a spacer group, s1, s2 each, independently of one another, denote 0 or 1, n1, n2 each, independently of one another, denote 0 or 1, Q denotes a single bond, —CF.sub.2O—, —OCF.sub.2—, —CH.sub.2O—, —OCH.sub.2—, —(CO)O—, —O(CO)—, —(CH.sub.2).sub.4—, —CH.sub.2—CH.sub.2—, —CF.sub.2—CF.sub.2—, —CF.sub.2—CH.sub.2—, —CH.sub.2—CF.sub.2—, —CH═CH—, —CF═CF—, —CF═CH—, —(CH.sub.2).sub.3O—, —O(CH.sub.2).sub.3—, —CH═CF—, —C≡C—, —O—, —CH.sub.2—, —(CH.sub.2).sub.3—, —CF.sub.2—, Z.sup.1, Z.sup.4 denote a single bond, —CF.sub.2O—, —OCF.sub.2—, —CH.sub.2O—, —OCH.sub.2—, —(CO)O—, —O(CO)—, —(CH.sub.2).sub.4—, —CH.sub.2—CH.sub.2—, —CF.sub.2—CF.sub.2—, —CF.sub.2—CH.sub.2—, —CH.sub.2—CF.sub.2—, —CH═CH—, —CF═CF—, —CF═CH—, —(CH.sub.2).sub.3O—, —O(CH.sub.2).sub.3—, —CH═CF—, —C≡C—, —O—, —CH.sub.2—, —(CH.sub.2).sub.3—, —CF.sub.2—, where Z.sup.1 and Q or Z.sup.4 and Q do not simultaneously denote a group selected from CF.sub.2O— and —OCF.sub.2—, A.sup.1, A.sup.2, A.sup.3, A.sup.4 each, independently of one another, denote a diradical group selected from the following groups: a) the group consisting of trans-1,4-cyclohexylene, 1,4-cyclohexenylene and 1,4′-bicyclohexylene, in which, in addition, one or more non-adjacent CH.sub.2 groups may be replaced by —O— and/or —S— and in which, in addition, one or more H atoms may be replaced by F, b) the group consisting of 1,4-phenylene and 1,3-phenylene, in which, in addition, one or two CH groups may be replaced by N and in which, in addition, one or more H atoms may be replaced by L, c) the group consisting of tetrahydropyran-2,5-diyl, 1,3-dioxane-2,5-diyl, tetrahydrofuran-2,5-diyl, cyclobutane-1,3-diyl, piperidine-1,4-diyl, thiophene-2,5-diyl and selenophene-2,5-diyl, each of which may also be mono- or polysubstituted by L, d) the group consisting of saturated, partially unsaturated or fully unsaturated, and optionally substituted, polycyclic radicals having 5 to 20 cyclic C atoms, one or more of which may, in addition, be replaced by heteroatoms, selected from the group consisting of bicyclo[1.1.1]pentane-1,3-diyl, bicyclo[2.2.2]octane-1,4-diyl, spiro[3.3]heptane-2,6-diyl, ##STR00284## where, in addition, one or more H atoms in these radicals may be replaced by L, and/or one or more double bonds may be replaced by single bonds, and/or one or more CH groups may be replaced by N, and A.sup.3, alternatively may be a single bond, L on each occurrence, identically or differently, denotes F, Cl, CN, SCN, SF.sub.5 or straight-chain or branched, in each case optionally fluorinated, alkyl having 1 to 12 C atoms, if branched is present, then 3 to 12 C atoms, alkoxy having 1 to 12 C atoms, if branched is present, then 3 to 12 C atoms, alkylcarbonyl having 2 to 12 C atoms, if branched is present, then 3 to 12 C atoms, alkoxycarbonyl having 2 to 12 C atoms, if branched is present, then 3 to 12 C atoms, alkylcarbonyloxy having 2 to 12 C atoms, if branched is present, then 3 to 12 C atoms, or-alkoxycarbonyloxy having 2 to 12 C atoms, if branched is present, then 3 to 12 C atoms, R.sup.03, R.sup.04 each, independently of one another, denote H, F or straight-chain or branched alkyl having 1 to 12 C atoms, if branched is present, then 3 to 12 C atoms, in which, in addition, one or more H atoms may be replaced by F, M denotes —O—, —S—, —CH.sub.2—, —CHY.sup.1— or —CY.sup.1Y.sup.2—, and Y.sup.1 and Y.sup.2 each, independently of one another, have one of the meanings indicated above for R.sup.03, or denote Cl or CN, and one of the groups Y.sup.1 and Y.sup.2 alternatively denotes —OCF.sub.3, where the total concentration of the compounds of the formulae I-2d, III-1, I, II and III is from 95% to 99.8% by weight, the concentration of compounds of formula III is from 10% to 40% by weight and the liquid crystal medium has a clearing temperature of 120° C. or more.

2. Liquid-crystal medium according to claim 1, which comprises one or more chiral compounds having an absolute value of the HTP of 10 μm or more.

3. Liquid-crystal medium according to claim 2, which comprises one or more chiral compounds selected from the group of compounds of formulae A-I to A-VI: ##STR00285## including the (R,S), (S,R), (R,R) and (S,S) enantiomers, which are not shown, ##STR00286## in which R.sup.a11 and R.sup.a12, independently of one another, are alkyl, oxaalkyl or alkenyl having from 2 to 9 carbon atoms, and R.sup.a11 is alternatively methyl or alkoxy having from 1 to 9 carbon atoms, R.sup.a21 and R.sup.a22, independently of one another, are alkyl or alkoxy having from 1 to 9 carbon atoms, oxaalkyl, alkenyl or alkenyloxy having from 2 to 9 carbon atoms, R.sup.a31 and R.sup.a32, independently of one another, are alkyl, oxaalkyl or alkenyl having from 2 to 9 carbon atoms, and R.sup.a11 is alternatively methyl or alkoxy having from 1 to 9 carbon atoms, ##STR00287## are each, independently of one another, 1,4-phenylene, which may also be mono-, di- or trisubstituted by L, or 1,4-cyclohexylene, L is H, F, Cl, CN or optionally halogenated alkyl having 1-7 carbon atoms, alkoxy having 1-7 carbon atoms, alkylcarbonyl having 2-7 carbon atoms, alkoxycarbonyl having 2-7 carbon atoms or alkoxycarbonyloxy having 2-7 carbon atoms, c is 0 or 1, Z.sup.0 is —COO—, —OCO—, —CH.sub.2CH.sub.2— or a single bond, and R.sup.0 is alkyl having 1-12 carbon atoms, alkoxy having 1-12 carbon atoms, alkylcarbonyl having 2-12 carbon atoms, alkoxycarbonyl having 2-12 carbon atoms or alkylcarbonyloxy having 2-12 carbon atoms, X.sup.1, X.sup.2, Y1 and Y.sup.2 are each, independently of one another, F, Cl, Br, I, CN, SCN, SF.sub.5, straight-chain alkyl having from 1 to 25 carbon atoms or branched alkyl having from 3 to 25 carbon atoms, which may be monosubstituted or polysubstituted by F, Cl, Br, I or CN and in which, in addition, one or more non-adjacent CH.sub.2 groups may each, independently of one another, be replaced by —O—, —S—, —NH—, NR.sup.0—, —CO—, —COO—, —OCO—, —OCOO—, —S—CO—, —CO—S—, —CH═CH— or —C≡C— in such a way that 0 and/or S atoms are not bonded directly to one another, a polymerisable group or cycloalkyl or aryl having 3 to 20 carbon atoms, which may optionally be monosubstituted or polysubstituted by halogen or by a polymerisable group, x.sup.1 and x.sup.2 are each, independently of one another, 0, 1 or 2, y.sup.1 and y.sup.2 are each, independently of one another, 0, 1, 2, 3 or 4, B.sup.1 and B.sup.2 are each, independently of one another, an aromatic or partially or fully saturated aliphatic six-membered ring in which one or more CH groups may be replaced by N atoms and one or more non-adjacent CH.sub.2 groups may be replaced by O and/or S, W.sup.1 and W.sup.2 are each, independently of one another, —Z.sup.1-A.sup.1-(Z.sup.2-A.sup.2).sub.m-R, and one of the two is alternatively R.sup.1 or A.sup.3, but both are not simultaneously H, or ##STR00288## U.sup.1 and U.sup.2 are each, independently of one another, CH.sub.2, O, S, CO or CS, V.sup.1 and V.sup.2 are each, independently of one another, (CH.sub.2).sub.n, in which from one to four non-adjacent CH.sub.2 groups may be replaced by O and/or S, and one of V.sup.1 and V.sup.2 and, in the case where ##STR00289## both are a single bond, Z.sup.1 and Z.sup.2 are each, independently of one another, —O—, —S—, —CO—, —COO—, —OCO—, —O—COO—, —CO—NR.sup.0—, —NR.sup.0—CO—, —O—CH.sub.2—, —CH.sub.2—O—, —S—CH.sub.2—, —CH.sub.2—S—, —CF.sub.2—O—, —O—CF.sub.2—, —CF.sub.2—S—, —S—CF.sub.2—, —CH.sub.2—CH.sub.2—, —CF.sub.2—CH.sub.2—, —CH.sub.2—CF.sub.2—, —CF.sub.2—CF.sub.2—, —CH═N—, —N═CH—, —N═N—, —CH═CH—, —CF═CH—, —CH═CF—, —CF═C F—, —C≡C—, a combination of two of these groups, where no two O and/or S and/or N atoms are bonded directly to one another, or a single bond, A.sup.1, A.sup.2 and A.sup.3 are each, independently of one another, 1,4-phenylene, in which one or two non-adjacent CH groups may be replaced by N, 1,4-cyclohexylene, in which one or two non-adjacent CH.sub.2 groups may be replaced by O and/or S, 1,3-dioxolane-4,5-diyl, 1,4-cyclohexenylene, 1,4-bicyclo[2.2.2]octylene, piperidine-1,4-diyl, naphthalene-2,6-diyl, decahydronaphthalene-2,6-diyl or 1,2,3,4-tetrahydronaphthalene-2,6-diyl, where each of these groups may be monosubstituted or polysubstituted by L, and in addition A.sup.1 is a single bond, L is a halogen atom, CN, NO.sub.2, alkyl having 1-7 carbon atoms, alkoxy having 1-7 carbon atoms, alkylcarbonyl having 2-7 carbon atoms, alkoxycarbonyl having 2-7 carbon atoms or alkoxycarbonyloxy having 2-7 carbon atoms, in which one or more H atoms may be replaced by F or Cl, m is in each case, independently, 0, 1, 2 or 3, and R and R.sup.1 are each, independently of one another, H, F, Cl, Br, I, CN, SCN, SF.sub.5, straight-chain or branched alkyl having from 1 to 25 carbon atoms, if branched is present, then 3 to 25 C atoms, which may optionally be monosubstituted or polysubstituted by F, Cl, Br, I or CN, and in which one or more non-adjacent CH.sub.2 groups may be replaced by —O—, —S—, —NH—, —NR.sup.0—, —CO—, —COO—, —OCO—, —O—COO—, —S—CO—, —CO—S—, —CH═CH— or —C≡C—, where no two O and/or S atoms are bonded directly to one another, or a polymerisable group.

4. Liquid-crystal medium according to claim 1, which additionally comprises one or more compounds of the formula I, as indicated in claim 1.

5. Liquid-crystal medium according to claim 1, which additionally comprises one or more compounds of formula II, as indicated in claim 1.

6. Liquid-crystal medium according to claim 1, which comprises one or more additional compounds of formulae III, as indicated in claim 1.

7. Liquid-crystal medium according to claim 1, which in addition to one or more compounds of formula I-2d, one or more compounds of formula III-1 and one or more compounds of formulas I, II and III, comprises one or more additional compounds selected from the group of compounds of formulae I-1, I-2, II-1 to II-3 and III-2 to III-6 ##STR00290## ##STR00291## in which the parameters have the respective meanings given in claim 1.

8. Liquid-crystal medium according to claim 1, which comprises a polymerizable compound and optionally additionally comprises a polymerisation initiator.

9. A method of improving the response time of a liquid-crystal medium comprising using one or more chiral compounds in a liquid-crystal medium in an amount sufficient to improve switching times of the liquid-crystal medium and within the range of 0.2% to 0.8% by weight based on the total weight of the liquid-crystal medium, said liquid crystal medium comprising—one or more compounds of formulae III-1 ##STR00292## and one or more additional compounds of formulae I and II and III ##STR00293## in which R denotes 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, n denotes 1, and ##STR00294## independently of one another, denote ##STR00295## alternatively denotes ##STR00296## in which R.sup.2 denotes 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, Z.sup.21 denotes trans-CH═CH—, trans-CF═CF— or —C≡C—, and ##STR00297## independently of one another, denote ##STR00298## in which R.sup.3 denotes 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, 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 trans CH═CH—, trans-CF═CF— or a single bond, and ##STR00299## independently of one another, denote ##STR00300## alternatively independently denotes ##STR00301## and optionally one or more polymerisable compounds of formula P
P.sup.a-(Sp.sup.a).sub.s1-(A.sup.1-Z.sup.1).sub.n1-A.sup.2-Q-A.sup.3-(Z.sup.4-A.sup.4).sub.n2-(Sp.sup.b).sub.s2-P.sup.b  P wherein the individual radicals have the following meanings: P.sup.a, P.sup.b each, independently of one another, are a polymerisable group, Sp.sup.a, Sp.sup.b each, independently of one another, denote a spacer group, s1, s2 each, independently of one another, denote 0 or 1, n1, n2 each, independently of one another, denote 0 or 1, Q denotes a single bond, —CF.sub.2O—, —OCF.sub.2—, —CH.sub.2O—, —OCH.sub.2—, —(CO)O—, —O(CO)—, —(CH.sub.2).sub.4—, —CH.sub.2—CH.sub.2—, —CF.sub.2—CF.sub.2—, —CF.sub.2—CH.sub.2—, —CH.sub.2—CF.sub.2—, —CH═CH—, —CF═CF—, —CF═CH—, —(CH.sub.2).sub.3O—, —O(CH.sub.2).sub.3—, —CH═CF—, —C≡C—, —O—, —CH.sub.2—, —(CH.sub.2).sub.3—, —CF.sub.2—, Z.sup.1, Z.sup.4 denote a single bond, —CF.sub.2O—, —OCF.sub.2—, —CH.sub.2O—, —OCH.sub.2—, —(CO)O—, —O(CO)—, —(CH.sub.2).sub.4—, —CH.sub.2—CH.sub.2—, —CF.sub.2—CF.sub.2—, —CF.sub.2—CH.sub.2—, —CH.sub.2—CF.sub.2—, —CH═CH—, —CF═CF—, —CF═CH—, —(CH.sub.2).sub.3O—, —O(CH.sub.2).sub.3—, —CH═CF—, —C≡C—, —O—, —CH.sub.2—, —(CH.sub.2).sub.3—, —CF.sub.2—, where Z.sup.1 and Q or Z.sup.4 and Q do not simultaneously denote a group selected from CF.sub.2O— and —OCF.sub.2—, A.sup.1, A.sup.2, A.sup.3, A.sup.4 each, independently of one another, denote a diradical group selected from the following groups: a) the group consisting of trans-1,4-cyclohexylene, 1,4-cyclohexenylene and 1,4′-bicyclohexylene, in which, in addition, one or more non-adjacent CH.sub.2 groups may be replaced by —O— and/or —S— and in which, in addition, one or more H atoms may be replaced by F, b) the group consisting of 1,4-phenylene and 1,3-phenylene, in which, in addition, one or two CH groups may be replaced by N and in which, in addition, one or more H atoms may be replaced by L, c) the group consisting of tetrahydropyran-2,5-diyl, 1,3-dioxane-2,5-diyl, tetrahydrofuran-2,5-diyl, cyclobutane-1,3-diyl, piperidine-1,4-diyl, thiophene-2,5-diyl and selenophene-2,5-diyl, each of which may also be mono- or polysubstituted by L, d) the group consisting of saturated, partially unsaturated or fully unsaturated, and optionally substituted, polycyclic radicals having 5 to 20 cyclic C atoms, one or more of which may, in addition, be replaced by heteroatoms, selected from the group consisting of bicyclo[1.1.1]pentane-1,3-diyl, bicyclo[2.2.2]octane-1,4-diyl, spiro[3.3]heptane-2,6-diyl, ##STR00302## where, in addition, one or more H atoms in these radicals may be replaced by L, and/or one or more double bonds may be replaced by single bonds, and/or one or more CH groups may be replaced by N, and A.sup.3, alternatively may be a single bond, L on each occurrence, identically or differently, denotes F, Cl, CN, SCN, SF.sub.5 or straight-chain or branched, in each case optionally fluorinated, alkyl having 1 to 12 C atoms, if branched is present, then 3 to 12 C atoms, alkoxy having 1 to 12 C atoms, if branched is present, then 3 to 12 C atoms, alkylcarbony having 2 to 12 C atoms, if branched is present, then 3 to 12 C atoms, alkoxycarbonyl having 2 to 12 C atoms, if branched is present, then 3 to 12 C atoms, alkylcarbonyloxy having 2 to 12 C atoms if branched is present, then 3 to 12 C atoms, or alkoxycarbonyloxy having 2 to 12 C atoms, if branched is present, then 3 to 12 C atoms, R.sup.03, R.sup.04 each, independently of one another, denote H, F or straight-chain or branched alkyl having 1 to 12 C atoms, if branched is present, then 3 to 12 C atoms, in which, in addition, one or more H atoms may be replaced by F, M denotes —O—, —S—, —CH.sub.2—, —CHY.sup.1— or —CY.sup.1Y.sup.2—, and Y.sup.1 and Y.sup.2 each, independently of one another, have one of the meanings indicated above for R.sup.03, or denote Cl or CN, and one of the groups Y.sup.1 and Y.sup.2 alternatively denotes —OCF.sub.3 where the total concentration of the compounds of the formulae III-1, I, II and III is from 95% to 99.8%.

10. Component for high-frequency technology, which comprises a liquid crystal medium according to claim 1.

11. Component according to claim 10, which is suitable for operation in the microwave range.

12. Component according to claim 10, which is a phase shifter or a LC based antenna element operable in the microwave region.

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

14. Process for the preparation of a liquid-crystal medium, wherein one or more chiral compounds are mixed with: one or more compounds selected from the group of the compounds of the formulae I, II and III, as specified in claim 1, wherein the amount of one or more chiral compounds is sufficient to improve switching times of the liquid-crystal medium and is within the range of 0.2% to 0.8% by weight based on the total weight of the liquid-crystal medium; and optionally with one or more further compounds and/or with one or more additives.

15. Microwave antenna array, which comprises one or more components according to claim 10.

Description

EXAMPLES

(1) The following examples illustrate the present invention without limiting it in any way.

(2) 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.

Examples 1 to 17 and Comparative Example

Comparative Example

(3) A liquid-crystal mixture C-1 having the composition and properties as indicated in the following table is prepared and characterized with respect to its general physical properties and its applicability in microwave

(4) TABLE-US-00007 Composition Compound Conc./ No. Abbreviation mass-% 1 PPTUI-3-2 20.0 2 PPTUI-3-4 36.0 3 GGP-3-CL 10.0 4 GGP-5-CL 20.0 5 CPGP-5-2 7.0 6 CPGP-5-3 7.0 Σ 100.0 Physical Properties T(N, I)/° C. = 173 Δn(20° C., 589.3 nm) = 0.335 Δε(20° C., 1 kHz) = 4.6 γ.sub.1 (20° C.)/mPa .Math. s = 746 tan δ.sub.εr,⊥ (20° C., 19 GHz) = 0.0143 tan δ.sub.εr,|| (20° C., 19 GHz) = 0.0038 τ (20° C., 19 GHz) = 0.252 η (20° C., 19 GHz) = 17.6

(5) This mixture is suitable for applications in the microwave range, in particular for phase shifters or LC based antenna elements in the micro wave (MW) region, however its response times are only moderate and not sufficient for more demanding applications.

Example 1

(6) A liquid-crystal mixture C-1 having the composition and properties as indicated in the following table is prepared and characterized with respect to its general physical properties and its applicability in microwave components at 19 GHz.

(7) TABLE-US-00008 Composition Compound No Abbreviation Conc./mass-% 1 PU-3-S 10.0 2 PTU-3-S 10.0 3 PTU-5-S 10.0 4 CGU-2-S 20.0 5 CGU-4-S 20.0 6 PGU-3-S 16.0 7 PPTU-4-S 7.0 8 PPTU-5-S 7.0 Σ 100.0 Physical Properties T (N, I)/° C. = 123 n.sub.o (20° C., 589.3 nm) = t.b.d. Δn (20° C., 589.3 nm) = t.b.d. ε.sub.∥ (20° C., 1 kHz) = 26.9 Δε (20° C., 1 kHz) = 4.7 γ.sub.1 (20° C.)/mPa .Math. s = 287 k.sub.1 (20° C.)/pN = 14.0 k.sub.3/k.sub.1 (20° C.) = 1.39 V.sub.0 (20° C.)/V = 0.84 ε.sub.r, ⊥ (20° C., 19 GHz) = 2.36 ε.sub.r, ∥ (20° C., 19 GHz) = 3.42 tan δ.sub.ε r, ⊥ (20° C., 19 GHz) = 0.0116 tan δ.sub.ε r, ∥ (20° C., 19 GHz) = 0.0066 τ (20° C., 19 GHz) = 0.310 η (20° C., 19 GHz) = 26.7 Remarks: t.b.d.: to be determined

(8) This mixture is suitable for applications in the microwave range, in particular for phase shifters or LC based antenna elements in the micro wave (MW) region. In comparison to the comparative examplethis mixture clearly exhibits superior response times.

Examples 1.1 and 1.2

(9) The mixture C-1 is divided into three parts. To each one of two these two parts a certain concentration of the chiral dopant S-1011 as shown in table F above, having a negative value of the HTP, is added.

(10) To one each of these two parts alternatively 0.20% of S-1011 and 0.40% of S-1011 are added, respectively.

(11) The two resultant mixtures are called M-1.1 and M-1.2. These two mixtures each are filled into test cells with antiparallel rubbed glas substrates covered by PI A13046. The test cells have a cell gap of 50 μm.

(12) TABLE-US-00009 TABLE 1 Compositions of the mixtures investigated Material C-1 S-1011 Example Mixture Composition Number Concentration/mass-% C-1 100.00 0.00 1.1 99.80 0.20 1.2 99.60 0.40

(13) TABLE-US-00010 TABLE 2 Physical Properties (at 20° C.) of the mixtures investigated Mixture C-1 M-1.1 M-1.2 Property Value T (N, I)/° C. t.b.d. t.b.d. t.b.d. Δn (20° C., 589.3 nm) t.b.d. t.b.d. t.b.d. Δε (20° C., 1 kHz) t.b.d. t.b.d. t.b.d. γ.sub.1 (20° C.)/mPa .Math. s t.b.d. t.b.d. t.b.d. V.sub.0/V t.b.d. t.b.d. t.b.d. Remarks: t.b.d.: to be determined, V.sub.0 in 91 μm test cell, described above.

(14) TABLE-US-00011 TABLE 3 Microwave characteristics and response times (at 20° C.) of the mixtures investigated Mixture C-1 M-1.1 M-1.2 Property Value tan δ.sub.ε r, ⊥ (20° C., 19 GHz) t.b.d. t.b.d. t.b.d. tan δ.sub.ε r, ∥ (20° C., 19 GHz) t.b.d. t.b.d. t.b.d. τ (20° C., 19 GHz) t.b.d. t.b.d. t.b.d. η (20° C., 19 GHz) t.b.d. t.b.d. t.b.d. τ.sub.on/s t.b.d. t.b.d. t.b.d. τ.sub.off/s 4.1 1.0 0.25 τ.sub.sum/s t.b.d. t.b.d. t.b.d. Remarks: t.b.d.: to be determined.

(15) These two mixtures are very highly suitable for applications in the microwave range, in particular for phase shifters or LC based antenna elements in the micro wave (MW) region. Additionally in comparison to the Examples 1.1 and 1.2 these mixtures clearly exhibit superior, i.e. significanly samller, response times. Mixture M-1.2, which is comprisuing the higher concentration of the chiral compound compared to M-1.1, has an even more strongly improved response behaviour.

(16) The switching times are determined from the electro-optical response in test cells with antiparallel rubbed polyimide (PI) orientation layers on top of ITO electrodes on glass substrates. These cells have a cell gap of 91 μm. They are investigated in an optical setup as follows. A test cell is mounted on a temperature-controlled chuck (20° C.) with an antireflective layer between the test cell and the chuck. The test cell is illuminated by a white LED light source from an angle of 45°. No polarizers are used on the test cell.

(17) A rectangular bipolar bias voltage with a frequency of 1 kHz and an amplitude of 100 V is applied to the LC layer in the test cell. This bias voltage is subsequently switched on and off. The test cell is placed in the light path of a microscope (objective lens 5×) and can thus be can be visually observed and inspected. During the switching operation, the brightness of the cell observed through the microscope changes following the changes in the bias voltage. A photodiode installed within the light path of the microscope is used to record the change of the brightness of the LC layer investigated in the test cell via an external photodiode amplifier (Thorlabs PDA200C).

(18) The response times for switching on and for switching off are determined for the time required to change the relative intensity of reflectionfrom 10% to 90% and vice versa, respectively.
τ.sub.on≡t(10%)−t(90%)
τ.sub.off≡t(90%)−t(10%)

Example 2

(19) A liquid-crystal mixture M-2 having the composition and properties as indicated in the following table is prepared and characterized with respect to its general physical properties and its applicability in microwave components at 19 GHz.

(20) TABLE-US-00012 Composition Compound No Abbreviation Conc./mass-% 1 PU-3-S 16.0 2 PVG-4-S 13.0 3 PVG-5-S 13.0 4 PTU-3-S 7.0 5 PTU-5-S 7.0 6 PGU-3-S 24.0 7 PPTU-4-S 10.0 8 PPTU-5-S 10.0 Σ 100.0 Physical Properties T (N, I)/° C. = 100 n.sub.o (20° C., 589.3 nm) = t.b.d. Δn (20° C., 589.3 nm) = t.b.d. ε.sub.∥ (20° C., 1 kHz) = 28.2 Δε (20° C., 1 kHz) = 5.0 γ.sub.1 (20° C.)/mPa .Math. s = 245 tan δ.sub.ε r, ⊥ (20° C., 19 GHz) = t.b.d. tan δ.sub.ε r, ∥ (20° C., 19 GHz) = t.b.d. τ (20° C., 19 GHz) = t.b.d. η (20° C., 19 GHz) = t.b.d. Remark: t.b.d.: to be determined.
k.sub.11=15.8 pN; k.sub.33=15.1 V; V.sub.10=0.87 V

(21) This mixture is suitable for applications in the microwave range, in particular for phase shifters or LC based antenna elements in the micro wave (MW) region. In comparison to the Comparison Example 1 this mixture clearly exhibits superior response times.

Example 3

(22) A liquid-crystal mixture M-3 having the composition and properties as indicated in the following table is prepared and characterized with respect to its general physical properties and its applicability in microwave components at 19 GHz.

(23) TABLE-US-00013 Composition Compound No Abbreviation Conc./mass-% 1 PU-3-S 18.0 2 PVG-4-S 13.0 3 PVG-5-S 13.0 4 PTU-3-S 8.0 5 PTU-5-S 8.0 6 PGU-3-S 20.0 7 PPTU-4-S 10.0 8 PPTU-5-S 10.0 Σ 100.0 Physical Properties T (N, I)/° C. = 93 n.sub.o (20° C., 589.3 nm) = t.b.d. Δn (20° C., 589.3 nm) = t.b.d. ε.sub.∥ (20° C., 1 kHz) = 27.7 Δε (20° C., 1 kHz) = 5.0 γ.sub.1 (20° C.)/mPa .Math. s = 225 tan δ.sub.ε r, ⊥ (20° C., 19 GHz) = t.b.d. tan δ.sub.ε r, ∥ (20° C., 19 GHz) = t.b.d. τ (20° C., 19 GHz) = t.b.d. η (20° C., 19 GHz) = t.b.d. Remark: t.b.d.: to be determined.
k.sub.11=15.0 pN; k.sub.33=15.4 V; V.sub.10=0.86 V

(24) This mixture is suitable for applications in the microwave range, in particular for phase shifters or LC based antenna elements in the micro wave (MW) region. In comparison to the comparative example this mixture clearly exhibits superior response times.

(25) TABLE-US-00014 TABLE 5 Comparison of the properties at 19 GHz and 20° C. Example Liquid crystal Δε.sub.r⊥ δ.sub.ε r, ⊥ η 1 M-1 0.56 0.013 14.5 Comparison 5CB 0.026 4.3

Example 4

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

(27) TABLE-US-00015 Composition Compound No Abbreviation Conc./mass-% 1 CP-3-CL 10.0 2 PVG-4-S 11.0 3 PVG-5-S 11.0 4 PTU-3-S 10.0 5 PTU-5-S 10.0 6 CPU-3-S 14.0 7 PGU-3-S 20.0 8 PPTU-4-S 7.0 9 PPTU-5-S 7.0 Σ 100.0 Physical Properties T (N, I)/° C. = 72 n.sub.e (20° C., 589.3 nm) = t.b.d. Δn (20° C., 589.3 nm) = t.b.d. ε.sub.∥ (20° C., 1 kHz) = 24.5 Δε (20° C., 1 kHz) = 5.1 k.sub.11 (20° C.)/pN = 11.3 k.sub.33 (20° C.)/pN = 13.2 V.sub.0 (20° C.)/V = 0.81 γ.sub.1 (20° C.)/mPa .Math. s = 162 tan δ.sub.ε r, max (20° C., 19 GHz) = t.b.d. τ (20° C., 19 GHz) = t.b.d. η (20° C., 19 GHz) = t.b.d. Remark: t.b.d.: to be determined.

(28) This mixture is very highly suitable for applications in the microwave range, in particular for phase shifters or LC based antenna elements in the MW region.

Example 5

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

(30) TABLE-US-00016 Composition Compound No Abbreviation Conc./mass-% 1 PVG-3-S 6.0 2 PVG-4-S 16.0 3 PVG-5-S 6.0 4 PTG-3-S 10.0 5 PTG-5-S 10.0 6 PTU-3-S 8.0 7 PGU-3-S 8.0 8 PPTU-4-S 16.0 9 PPTU-5-S 16.0 Σ 100.0 Physical Properties T (N, I)/° C. = 112 n.sub.o (20° C., 589.3 nm) = 1.5454 Δn (20° C., 589.3 nm) = t.b.d. ε.sub.∥ (20° C., 1 kHz) = 25.7 Δε (20° C., 1 kHz) = 4.4 γ.sub.1 (20° C.)/mPa .Math. s = 270 tan δ.sub.ε r, ⊥ (20° C., 19 GHz) = 0.0143 tan δ.sub.ε r, ∥ (20° C., 19 GHz) = 0.0038 τ (20° C., 19 GHz) = 0.252 η (20° C., 19 GHz) = 17.6 Remark: t.b.d.: to be determined.

(31) This mixture is very highly suitable for applications in the microwave range, in particular for phase shifters or LC based antenna elements in the MW region.

Example 6

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

(33) TABLE-US-00017 Composition Compound No Abbreviation Conc./mass-% 1 CP-1V-O1 10.0 2 PVG-4-S 11.0 3 PVG-5-S 11.0 4 PTU-3-S 10.0 5 PTU-5-S 10.0 6 CPU-3-S 14.0 7 PGU-3-S 20.0 8 PPTU-4-S 7.0 9 PPTU-5-S 7.0 Σ 100.0 Physical Properties T (N, I)/° C. = 75.5 n.sub.e (20° C., 589.3 nm) = t.b.d. Δn (20° C., 589.3 nm) = t.b.d. ε.sub.∥ (20° C., 1 kHz) = 24.2 Δε (20° C., 1 kHz) = 5.1 k.sub.11 (20° C.)/pN 11.7 k.sub.33 (20° C.)/pN 13.6 V.sub.0 (20° C.)/V 0.83 γ.sub.1 (20° C.)/mPa .Math. s = 178 tan δ.sub.εr, max (20° C., 19 GHz) = τ (20° C., 19 GHz) = η (20° C., 19 GHz) = Remark: t.b.d.: to be determined.

(34) This mixture is very highly suitable for applications in the microwave range, in particular for phase shifters or LC based antenna elements in the MW region.

Example 7

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

(36) TABLE-US-00018 Composition Compound No Abbreviation Conc./mass-% 1 GGP-3-S 12.0 2 PGG-3-S 8.0 3 PGU-3-S 12.0 4 PVG-3-S 6.0 5 PVG-4-S 16.0 6 PTG-3-S 10.0 7 PTG-5-S 18.0 8 PTU-3-S 10.0 9 PPTU-4-S 6.0 Σ 100.0 Physical Properties T (N, I)/° C. = 98 n.sub.e (20° C., 589.3 nm) = t.b.d. Δn (20° C., 589.3 nm) = t.b.d. ε.sub.∥ (20° C., 1 kHz) = 26.7 Δε (20° C., 1 kHz) = t.b.d. k.sub.11 (20° C.)/pN 17.7 k.sub.33 (20° C.)/pN 15.7 V.sub.0 (20° C.)/V 0.96 γ.sub.1 (20° C.)/mPa .Math. s = 698 tan δ.sub.ε r, max (20° C., 19 GHz) = 0.0189 τ (20° C., 19 GHz) = 0.336 η (20° C., 19 GHz) = 17.9 Remark: t.b.d.: to be determined.

(37) This mixture is very highly suitable for applications in the microwave range, in particular for phase shifters or LC based antenna elements in the MW region.

Examples 8 to 12

(38) To the liquid crystalline medium M-7 of Example 7 alternatively a certain concentration of a further single compound one each is added and the resultant mixtures (M-8 to M-12) are investigated for their general physical properties and for their performance in the microwave regime.

(39) TABLE-US-00019 Composition Example Mixture Compound c (Comp.) c (M-4) No. No. Abbreviation /% 7 M-7 None 0.0 100.0 8 M-8 PTPI(c3)TU-4-F 5.0 95.0 9 M-9 PTPI(2)WU-6-F 10.0 90.0 10 M-10 PTPI(2)GU-4-F 10.0 90.0 11 M-11 PTG(c3)TU-4-F 5.0 95.0 12 M-12 PTN(1, 4)TP-3-F 5.0 95.0

(40) TABLE-US-00020 Physical Rroperties I, General I (20° C. except T(N.I)) Example Mixture T (N, I)/ No. No. ° C. Δn ε.sub.∥ Δε 7 M-7 98 t.b.d. 26.7 21.5 8 M-8 98 t.b.d. 26.1 20.9 9 M-9 90 t.b.d. 26.0 21.0 10 M-10 102 t.b.d. 27.0 21.9 11 M-11 93.9 t.b.d. 27.0 21.8 12 M-12 99.5 t.b.d. 25.9 20.9 Remark: t.b.d.: to be determined.

(41) TABLE-US-00021 Physical Rroperties II, General II (20° C.) Example Mixture No. No. γ.sub.1 k.sub.11/pN k.sub.33/pN V.sub.0/V 7 M-7 241 17.7 15.7 0.96 8 M-8 254 15.1 14.6 0.90 9 M-9 272 15.8 15.8 0.91 10 M-10 319 16.0 16.9 0.90 11 M-11 257 15.8 15.0 0.90 12 M-12 273 18.2 15.9 0.99

(42) TABLE-US-00022 Physical Rroperties III Microwave I (20° C., 19 GHz) Example Mixture No. No. ε.sub.r, ⊥ ε.sub.r, ∥ tan δ.sub.ε r, ∥ tan δ.sub.ε r, ⊥ 7 M-7 3.74 2.49 0.0189 0.0091 8 M-8 3.68 2.48 0.0177 0.0088 9 M-9 3.67 2.49 0.0174 0.0084 10 M-10 3.68 2.48 0.0170 0.0082 11 M-11 3.70 2.49 0.0180 0.0088 12 M-12 3.73 2.49 0.0175 0.0085

(43) TABLE-US-00023 Physical Rroperties IV, Microwave II (20° C., 19 GHz) Example Mixture No. No. tan δ.sub.εr,⊥ τ.sub.εr η 7 M-7 0.0189 0.336 17.8 8 M-8 0.0177 0.326 18.4 9 M-9 0.0174 0.323 18.6 10 M-10 0.0170 0.327 19.3 11 M-11 0.0180 0.327 18.1 12 M-12 0.0175 0.332 19.0

(44) These mixtures are very well suitable for applications in the microwave range, in particular for phase shifters or LC based antenna elements in the MW region.

(45) The mixtures of examples 7 to 12 are treated and investigated as described under example 1. The resultant mixtures comprising the chiral compound in the respective concentrations show similarly improved properties. They are especially characterized in particular by improved response times.

Example 13

(46) A liquid-crystal mixture M-13 having the composition and properties as indicated in the following table is prepared and characterized with respect to its general physical properties and its applicability in microwave components at 19 GHz.

(47) TABLE-US-00024 Composition Compound Conc./ No Abbreviation mass-% 1 PU-3-S 10.0 2 PTU-3-S 10.0 3 PTU-5-S 10.0 4 CGU-2-S 10.0 5 CGU-3-S 10.0 6 CGU-4-S 10.0 7 CGU-5-S 10.0 8 PGU-3-S 16.0 9 PPTU-4-S 7.0 10  PPTU-5-S 7.0 Σ 100.0 Physical Properties T(N, I)/° C. = 126.5 n.sub.o(20° C., 589.3 nm) = t.b.d. Δn(20° C., 589.3 nm) = t.b.d. ε.sub.||(20° C., 1 kHz) = 27.1 Δε(20° C., 1 kHz) = 4.5 γ.sub.1 (20° C.)/mPa .Math. s = 299 k.sub.1 (20° C.)/pN = 14.8 k.sub.3/k.sub.1 (20° C.) = 1.43 V.sub.0 (20° C.)/V = 0.86 ε.sub.r,⊥ (20° C., 19 GHz) = 2.36 ε.sub.r,|| (20° C., 19 GHz) = 3.44 tan δ.sub.εr,⊥ (20° C., 19 GHz) = 0.0116 tan δ.sub.εr,|| (20° C., 19 GHz) = 0.0064 τ (20° C., 19 GHz) = 0.315 η (20° C., 19 GHz) = 27.2 Remark: t.b.d.: to be determined.

(48) This mixture is suitable for applications in the microwave range, in particular for phase shifters or LC based antenna elements in the micro wave (MW) region. In comparison to the comparative example this mixture clearly exhibits superior response times.

Example 14

(49) A liquid-crystal mixture M-14 having the composition and properties as indicated in the following table is prepared and characterized with respect to its general physical properties and its applicability in microwave components at 19 GHz.

(50) TABLE-US-00025 Composition Compound Conc./ No Abbreviation mass-% 1 PU-3-S 14.0 2 PTU-3-S 14.0 3 CGU-2-S 20.0 4 CGU-4-S 20.0 5 PGU-3-S 18.0 6 PPTU-4-S 7.0 7 PPTU-5-S 7.0 Σ 100.0 Physical Properties T(N, I)/° C. = t.b.d. n.sub.o(20° C., 589.3 nm) = t.b.d. Δn(20° C., 589.3 nm) = t.b.d. ε.sub.||(20° C., 1 kHz) = t.b.d. Δε(20° C., 1 kHz) = t.b.d. γ.sub.1 (20° C.)/mPa .Math. s = t.b.d. k.sub.1 (20° C.)/pN = t.b.d. k.sub.3/k.sub.1 (20° C.) = t.b.d. V.sub.0 (20° C.)/V = t.b.d. ε.sub.r,⊥ (20° C., 19 GHz) = t.b.d. ε.sub.r,|| (20° C., 19 GHz) = t.b.d. tan δ.sub.εr,⊥ (20° C., 19 GHz) = t.b.d. tan δ.sub.εr,|| (20° C., 19 GHz) = t.b.d. τ (20° C., 19 GHz) = t.b.d. η (20° C., 19 GHz) = t.b.d. Remark: t.b.d.: to be determined.

(51) This mixture is suitable for applications in the microwave range, in particular for phase shifters or LC based antenna elements in the micro wave (MW) region. In comparison to the comparative example this mixture clearly exhibits superior response times.

Example 15

(52) A liquid-crystal mixture M-15 having the composition and properties as indicated in the following table is prepared and characterized with respect to its general physical properties and its applicability in microwave components at 19 GHz.

(53) TABLE-US-00026 Composition Compound Conc./ No Abbreviation mass-% 1 PU-3-S 8.0 2 PVG-4-S 8.0 3 PVG-5-S 8.0 4 PTU-3-S 8.0 5 PTU-5-S 8.0 6 CGU-3-S 10.0 7 CGU-4-S 10.0 8 CGU-5-S 10.0 9 PGU-3-S 16.0 9 PPTU-4-S 7.0 11  PPTU-5-S 7.0 Σ 100.0 Physical Properties T(N, I)/° C. = 121.5 n.sub.o(20° C., 589.3 nm) = t.b.d. Δn(20° C., 589.3 nm) = t.b.d. ε.sub.||(20° C., 1 kHz) = 26.2 Δε(20° C., 1 kHz) = 4.6 γ.sub.1 (20° C.)/mPa .Math. s = 298 k.sub.1 (20° C.)/pN = 16.0 k.sub.3/k.sub.1 (20° C.) = 1.31 V.sub.0 (20° C.)/V = 0.91 ε.sub.r,⊥ (20° C., 19 GHz) = 2.36 ε.sub.r,|| (20° C., 19 GHz) = 3.48 tan δ.sub.εr,⊥ (20° C., 19 GHz) = 0.0121 tan δ.sub.εr,|| (20° C., 19 GHz) = 0.0067 τ (20° C., 19 GHz) = 0.321 η (20° C., 19 GHz) = 26.5 Remark: t.b.d.: to be determined.

(54) This mixture is suitable for applications in the microwave range, in particular for phase shifters or LC based antenna elements in the micro wave (MW) region. In comparison to the comparative example this mixture clearly exhibits superior response times.

Example 16

(55) A liquid-crystal mixture M-16 having the composition and properties as indicated in the following table is prepared and characterized with respect to its general physical properties and its applicability in microwave components at 19 GHz.

(56) TABLE-US-00027 Composition Compound Conc./ No Abbreviation mass-% 1 PU-3-S 8.0 2 PVG-4-S 8.0 3 PVG-5-S 8.0 4 PTU-3-S 8.0 5 PTU-5-S 8.0 6 CGU-4-S 15.0 7 CGU-5-S 15.0 8 PGU-3-S 16.0 9 PPTU-4-S 7.0 10  PPTU-5-S 7.0 Σ 100.0 Physical Properties T(N, I)/° C. = 124 n.sub.o(20° C., 589.3 nm) = t.b.d. Δn(20° C., 589.3 nm) = t.b.d. ε.sub.||(20° C., 1 kHz) = 26.2 Δε(20° C., 1 kHz) = 4.6 γ.sub.1 (20° C.)/mPa .Math. s = 311 k.sub.1 (20° C.)/pN = 16.2 k.sub.3/k.sub.1 (20° C.) = 1.28 V.sub.0 (20° C.)/V = 0.91 ε.sub.r,⊥ (20° C., 19 GHz) = 2.37 ε.sub.r,|| (20° C., 19 GHz) = 3.48 tan δ.sub.εr,⊥ (20° C., 19 GHz) = 0.0120 tan δ.sub.εr,|| (20° C., 19 GHz) = 0.0066 τ (20° C., 19 GHz) = 0.318 η (20° C., 19 GHz) = 26.2 Remark: t.b.d.: to be determined.

(57) This mixture is suitable for applications in the microwave range, in particular for phase shifters or LC based antenna elements in the micro wave (MW) region. In comparison to the comparative example this mixture clearly exhibits superior response times.

Example 17

(58) A liquid-crystal mixture M-17 having the composition and properties as indicated in the following table is prepared and characterized with respect to its general physical properties and its applicability in microwave components at 19 GHz.

(59) TABLE-US-00028 Composition Compound Conc./ No Abbreviation mass-% 1 PU-3-S 10.0 2 PTU-3-S 10.0 3 PTU-5-S 10.0 4 CGU-2-S 14.0 5 CGU-3-S 13.0 6 CGU-4-S 13.0 7 PGU-3-S 16.0 8 PPTU-4-S 7.0 9 PPTU-5-S 7.0 Σ 100.0 Physical Properties T(N, I)/° C. = 126.5 n.sub.o(20° C., 589.3 nm) = t.b.d. Δn(20° C., 589.3 nm) = t.b.d. ε.sub.||(20° C., 1 kHz) = 27.4 Δε(20° C., 1 kHz) = 4.6 γ.sub.1 (20° C.)/mPa .Math. s = 297 k.sub.1 (20° C.)/ = 14.5 k.sub.3/k.sub.1 (20° C.) = 1.45 V.sub.0 (20° C.)/V = 0.84 ε.sub.r,⊥ (20° C., 19 GHz) = 2.36 ε.sub.r,|| (20° C., 19 GHz) = 3.44 tan δ.sub.εr,⊥ (20° C., 19 GHz) = 0.0115 tan δ.sub.εr,|| (20° C., 19 GHz) = 0.0065 τ (20° C., 19 GHz) = 0.313 η (20° C., 19 GHz) = 27.2 Remark: t.b.d.: to be determined.

(60) This mixture is suitable for applications in the microwave range, in particular for phase shifters or LC based antenna elements in the micro wave (MW) region. In comparison to the comparative example this mixture clearly exhibits superior response times.

Example 18

(61) A liquid-crystal mixture M-18 having the composition and properties as indicated in the following table is prepared and characterized with respect to its general physical properties and its applicability in microwave components at 19 GHz.

(62) TABLE-US-00029 Composition Compound Conc./ No Abbreviation mass-% 1 PVG-4-S 16.0 2 PVG-5-S 16.0 3 PTU-3-S 14.0 4 PTU-5-S 10.0 5 PTG-5-S 14.0 6 PGU-3-S 14.0 7 PPTU-4-S 15.0 8 PPTU-5-S 15.0 Σ 100.0 Physical Properties T(N, I)/° C. = 115.5 n.sub.o(20° C., 589.3 nm) = t.b.d. Δn(20° C., 589.3 nm) = t.b.d. ε.sub.||(20° C., 1 kHz) = 27.0 Δε(20° C., 1 kHz) = 4.5 γ.sub.1 (20° C.)/mPa .Math. s = 304 k.sub.1 (20° C.)/pN/ = t.b.d. k.sub.3/k.sub.1 (20° C.) = t.b.d. V.sub.0 (20° C.)/V = 1.07 ε.sub.r,⊥ (20° C., 19 GHz) = t.b.d. ε.sub.r,|| (20° C., 19 GHz) = t.b.d. tan δ.sub.εr,⊥ (20° C., 19 GHz) = t.b.d. tan δ.sub.εr,|| (20° C., 19 GHz) = t.b.d. τ (20° C., 19 GHz) = t.b.d. η (20° C., 19 GHz) = t.b.d. Remark: t.b.d.: to be determined.

(63) This mixture is suitable for applications in the microwave range, in particular for phase shifters or LC based antenna elements in the micro wave (MW) region. In comparison to the comparative example this mixture clearly exhibits superior response times.

Example 19

(64) A liquid-crystal mixture M-19 having the composition and properties as indicated in the following table is prepared and characterized with respect to its general physical properties and its applicability in microwave components at 19 GHz.

(65) TABLE-US-00030 Composition Compound Conc./ No Abbreviation mass-% 1 PU-3-S 20.0 2 PVG-4-S 16.0 3 PVG-5-S 16.0 4 PGU-3-S 16.0 5 PPTU-4-S 16.0 6 PPTU-5-S 16.0 Σ 100.0 Physical Properties T(N, I)/° C. = 116.5 n.sub.o(20° C., 589.3 nm) = t.b.d. Δn(20° C., 589.3 nm) = t.b.d. ε.sub.||(20° C., 1 kHz) = 27.7 Δε(20° C., 1 kHz) = 4.6 γ.sub.1 (20° C.)/mPa .Math. s = 292 k.sub.1 (20° C.)/pN = t.b.d. k.sub.3/k.sub.1 (20° C.) = t.b.d. V.sub.0 (20° C.)/V = 1.05 ε.sub.r,⊥ (20° C., 19 GHz) = t.b.d. ε.sub.r,|| (20° C., 19 GHz) = t.b.d. tan δ.sub.εr,⊥ (20° C., 19 GHz) = t.b.d. tan δ.sub.εr,|| (20° C., 19 GHz) = t.b.d. τ (20° C., 19 GHz) = t.b.d. η (20° C., 19 GHz) = t.b.d. Remark: t.b.d.: to be determined.

(66) This mixture is suitable for applications in the microwave range, in particular for phase shifters or LC based antenna elements in the micro wave (MW) region. In comparison to the comparative example this mixture clearly exhibits superior response times.

Example 20

(67) A liquid-crystal mixture M-20 having the composition and properties as indicated in the following table is prepared and characterized with respect to its general physical properties and its applicability in microwave components at 19 GHz.

(68) TABLE-US-00031 Composition Compound Conc./ No Abbreviation mass-% 1 PU-3-S 16.0 2 PVG-4-S 14.0 3 PVG-5-S 14.0 4 PTU-3-S 8.0 5 PTU-5-S 8.0 6 PGU-3-S 14.0 7 PPTU-4-S 10.0 8 PPTU-5-S 10.0 Σ 100.0 Physical Properties T(N, I)/° C. = 95 n.sub.o(20° C., 589.3 nm) = t.b.d. Δn(20° C., 589.3 nm) = t.b.d. ε.sub.||(20° C., 1 kHz) = 27.4 Δε(20° C., 1 kHz) = 5.0 γ.sub.1 (20° C.)/mPa .Math. s = 234 k.sub.1 (20° C.)/pN = 15.6 k.sub.3/k.sub.1 (20° C.) = 1.00 V.sub.0 (20° C.)/V = 0.88 ε.sub.r,⊥ (20° C., 19 GHz) = 2.56 ε.sub.r,|| (20° C., 19 GHz) = 3.68 tan δ.sub.εr,⊥ (20° C., 19 GHz) = 0.0075 tan δ.sub.εr,|| (20° C., 19 GHz) = 0.0136 τ (20° C., 19 GHz) = 0.306 η (20° C., 19 GHz) = 22.5 Remark: t.b.d.: to be determined.

(69) This mixture is suitable for applications in the microwave range, in particular for phase shifters or LC based antenna elements in the micro wave (MW) region. In comparison to the comparative example this mixture clearly exhibits superior response times.

Example 21

(70) A liquid-crystal mixture M-21 having the composition and properties as indicated in the following table is prepared and characterized with respect to its general physical properties and its applicability in microwave components at 19 GHz.

(71) TABLE-US-00032 Composition Compound Conc./ No Abbreviation mass-% 1 PU-3-S 20.0 2 PVG-4-S 15.0 3 PVG-5-S 15.0 4 PTU-3-S 10.0 5 PGU-3-S 14.0 6 PPTU-4-S 10.0 7 PPTU-5-S 10.0 Σ 100.0 Physical Properties T(N, I)/° C. = 96 n.sub.o(20° C., 589.3 nm) = t.b.d. Δn(20° C., 589.3 nm) = t.b.d. ε.sub.||(20° C., 1 kHz) = 27.8 Δε(20° C., 1 kHz) = 5.0 γ.sub.1 (20° C.)/mPa .Math. s = 230 k.sub.1 (20° C.)/pN = 15.6 k.sub.3/k.sub.1 (20° C.) = 1.00 V.sub.0 (20° C.)/V = 0.88 ε.sub.r,⊥ (20° C., 19 GHz) = 2.48 ε.sub.r,|| (20° C., 19 GHz) = 3.67 tan δ.sub.εr,⊥ (20° C., 19 GHz) = 0.0083 tan δ.sub.εr,|| (20° C., 19 GHz) = 0.0152 τ (20° C., 19 GHz) = 0.324 η (20° C., 19 GHz) = 21.0 Remark: t.b.d.: to be determined.

(72) This mixture is suitable for applications in the microwave range, in particular for phase shifters or LC based antenna elements in the micro wave (MW) region. In comparison to the comparative example this mixture clearly exhibits superior response times.

Example 22

(73) A liquid-crystal mixture M-22 having the composition and properties as indicated in the following table is prepared and characterized with respect to its general physical properties and its applicability in microwave components at 19 GHz.

(74) TABLE-US-00033 Composition Compound Conc./ No Abbreviation mass-% 1 PU-3-S 10.0 2 PTU-3-S 10.0 3 PTU-5-S 10.0 4 CPU-2-S 20.0 5 CPU-5-S 20.0 6 PGU-3-S 16.0 7 PPTU-4-S 7.0 8 PPTU-5-S 7.0 Σ 100.0 Physical Properties T(N, I)/° C. = 125 n.sub.o(20° C., 589.3 nm) = t.b.d. Δn(20° C., 589.3 nm) = t.b.d. ε.sub.||(20° C., 1 kHz) = 27.2 Δε(20° C., 1 kHz) = 4.6 γ.sub.1 (20° C.)/mPa .Math. s = 310 k.sub.1 (20° C.)/pN = 14.1 k.sub.3/k.sub.1 (20° C.) = 1.44 V.sub.0 (20° C.)/V = 0.85 ε.sub.r,⊥ (20° C., 19 GHz) = t.b.d. ε.sub.r,|| (20° C., 19 GHz) = t.b.d. tan δ.sub.εr,⊥ (20° C., 19 GHz) = t.b.d. tan δ.sub.εr,|| (20° C., 19 GHz) = t.b.d. τ (20° C., 19 GHz) = t.b.d. η (20° C., 19 GHz) = t.b.d. Remark: t.b.d.: to be determined.

(75) This mixture is suitable for applications in the microwave range, in particular for phase shifters or LC based antenna elements in the micro wave (MW) region. In comparison to the comparative example this mixture clearly exhibits superior response times.

Example 23

(76) A liquid-crystal mixture M-23 having the composition and properties as indicated in the following table is prepared and characterized with respect to its general physical properties and its applicability in microwave components at 19 GHz.

(77) TABLE-US-00034 Composition Compound Conc./ No Abbreviation mass-% 1 PU-3-S 10.0 2 PTU-3-S 10.0 3 PTU-5-S 10.0 4 CPU-2-S 20.0 5 CPU-3-S 20.0 6 PGU-3-S 16.0 7 PPTU-4-S 7.0 8 PPTU-5-S 7.0 Σ 100.0 Physical Properties T(N, I)/° C. = 124 n.sub.o(20° C., 589.3 nm) = t.b.d. Δn(20° C., 589.3 nm) = t.b.d. ε.sub.||(20° C., 1 kHz) = 27.8 Δε(20° C., 1 kHz) = 4.6 γ.sub.1 (20° C.)/mPa .Math. s = 301 k.sub.1 (20° C.)/pN = 14.1 k.sub.3/k.sub.1 (20° C.) = 1.44 V.sub.0 (20° C.)/V = 0.85 ε.sub.r,⊥ (20° C., 19 GHz) = t.b.d. ε.sub.r,|| (20° C., 19 GHz) = t.b.d. tan δ.sub.εr,⊥ (20° C., 19 GHz) = t.b.d. tan δ.sub.εr,|| (20° C., 19 GHz) = t.b.d. τ (20° C., 19 GHz) = t.b.d. η (20° C., 19 GHz) = t.b.d. Remark: t.b.d.: to be determined.

(78) This mixture is suitable for applications in the microwave range, in particular for phase shifters or LC based antenna elements in the micro wave (MW) region. In comparison to the comparative example this mixture clearly exhibits superior response times.

Example 24

(79) A liquid-crystal Mixture M-24 having the composition and properties as indicated in the following table is prepared and characterized with respect to its general physical properties and its applicability in microwave components at 19 GHz.

(80) TABLE-US-00035 Composition Compound Conc./ No Abbreviation mass-% 1 PU-3-S 10.0 2 PTU-3-S 10.0 3 PTU-5-S 10.0 4 PGU-3-S 16.0 5 PPTU-4-S 7.0 6 PPTU-5-S 7.0 7 CPU-2-S 10.0 8 CPU-3-S 10.0 9 CPU-4-S 10.0 10  CPU-5-S 10.0 Σ 100.0 Physical Properties T(N, I)/° C. = 127 n.sub.o(20° C., 589.3 nm) = t.b.d. Δn(20° C., 589.3 nm) = t.b.d. ε.sub.||(20° C., 1 kHz) = 27.1 ε.sub.⊥(20° C., 1 kHz) = 4.5 γ.sub.1 (20° C.)/mPa .Math. s = 299 k.sub.1 (20° C.)/pN = 14.8 k.sub.3/k.sub.1 (20° C.) = 1.43 V.sub.0 (20° C.)/V = 0.86 ε.sub.r,⊥ (20° C., 19 GHz) = 2.35 ε.sub.r,|| (20° C., 19 GHz) = 3.44 tan δ.sub.εr,⊥ (20° C., 19 GHz) = 0.0116 tan δ.sub.εr,|| (20° C., 19 GHz) = 0.064 τ (20° C., 19 GHz) = 0.315 η (20° C., 19 GHz) = 27.2 Remark: t.b.d.: to be determined.

(81) This mixture is suitable for applications in the microwave range, in particular for phase shifters or LC based antenna elements in the micro wave (MW) region. In comparison to the comparative example this mixture clearly exhibits superior response times.

Example 25

(82) A liquid-crystal mixture M-25 having the composition and properties as indicated in the following table is prepared and characterized with respect to its general physical properties and its applicability in microwave components at 19 GHz.

(83) TABLE-US-00036 Composition Compound Conc./ No Abbreviation mass-% 1 PU-3-S 8.0 2 PVG-4-S 8.0 3 PVG-5-S 8.0 4 PTU-3-S 8.0 5 PTU-5-S 8.0 6 PGU-3-S 16.0 7 PPTU-4-S 7.0 8 PPTU-5-S 7.0 9 CPU-3-S 10.0 10  CPU-4-S 10.0 11  CPU-5-S 10.0 Σ 100.0 Physical Properties T(N, I)/° C. = 122 n.sub.o(20° C., 589.3 nm) = t.b.d. Δn(20° C., 589.3 nm) = t.b.d. ε.sub.||(20° C., 1 kHz) = 26.2 ε.sub.⊥(20° C., 1 kHz) = 4.6 γ.sub.1 (20° C.)/mPa .Math. s = 298 k.sub.1 (20° C.)/pN = 16.0 k.sub.3/k.sub.1 (20° C.) = 1.31 V.sub.0 (20° C.)/V = 0.91 ε.sub.r,⊥ (20° C., 19 GHz) = 2.36 ε.sub.r,|| (20° C., 19 GHz) = 3.48 tan δ.sub.εr,⊥ (20° C., 19 GHz) = 0.0121 tan δ.sub.εr,|| (20° C., 19 GHz) = 0.0067 τ (20° C., 19 GHz) = 0.321 η (20° C., 19 GHz) = 26.5 Remark: t.b.d.: to be determined.

(84) This mixture is suitable for applications in the microwave range, in particular for phase shifters or LC based antenna elements in the micro wave (MW) region. In comparison to the comparative example this mixture clearly exhibits superior response times.

Example 26

(85) A liquid-crystal mixture M-26 having the composition and properties as indicated in the following table is prepared and characterized with respect to its general physical properties and its applicability in microwave components at 19 GHz.

(86) TABLE-US-00037 Composition Compound Conc./ No Abbreviation mass-% 1 PU-3-S 8.0 2 PVG-4-S 8.0 3 PVG-5-S 8.0 4 PTU-3-S 8.0 5 PTU-5-S 8.0 6 PGU-3-S 16.0 7 PPTU-4-S 7.0 8 PPTU-5-S 7.0 9 CPU-4-S 15.0 10  CPU-5-S 15.0 Σ 100.0 Physical Properties T(N, I)/° C. = 124 n.sub.o(20° C., 589.3 nm) = t.b.d. Δn(20° C., 589.3 nm) = t.b.d. ε.sub.||(20° C., 1 kHz) = 26.2 ε.sub.⊥(20° C., 1 kHz) = 4.6 γ.sub.1 (20° C.)/mPa .Math. s = 311 k.sub.1 (20° C.)/pN = 16.2 k.sub.3/k.sub.1 (20° C.) = 1.28 V.sub.0 (20° C.)/V = 0.91 ε.sub.r,⊥ (20° C., 19 GHz) = 2.37 ε.sub.r,|| (20° C., 19 GHz) = 3.48 tan δ.sub.εr,⊥ (20° C., 19 GHz) = 0.0120 tan δ.sub.εr,|| (20° C., 19 GHz) = 0.0066 τ (20° C., 19 GHz) = 0.318 η (20° C., 19 GHz) = 26.5 Remark: t.b.d.: to be determined.

(87) This mixture is suitable for applications in the microwave range, in particular for phase shifters or LC based antenna elements in the micro wave (MW) region. In comparison to the comparative example this mixture clearly exhibits superior response times.

(88) The mixtures M-2 to M-26 are divided into two parts each. To each one these two mixtures of the respective pairs alternatively 0.20% of S-1011 and 0.40% of S-1011 are added, respectively, as in example 1 an the resultant mixtures are called M-1.1 and M-1.2 are investigated as described under example 1.

(89) The resultant mixtures show similarly improved properties as Examples 1.1 and 1.2, in particular with regard to tunability and figure of merit.

(90) Alternatively to the chiral compound S-1011 also its enantiomer can be used with the same improved effect(s). Also other chiral compounds, e.g. typical chiral dopants for liquid crystal mixtures ma y be beneficially used to achieve essentially the same effect(s).