LIQUID-CRYSTALLINE MEDIUM

Abstract

A liquid-crystalline medium which contains at least one compound of the formula I,

##STR00001##

and at least one compound of the formula IA

##STR00002##

in which R.sup.1, R.sup.1*, R.sup.1A, R.sup.1A*, L.sup.1 and L.sup.2 have the meanings indicated in Claim 1. Uses of the medium in an active-matrix display or passive matrix display, for example based on the VA, PSA, PS-VA, PVA, MVA, PM-VA, PALC, FFS, UB-FFS, PS-FFS, IPS or PS-IPS effect.

Claims

1. A liquid-crystalline medium comprising a mixture of polar compounds, which comprises at least one compound of the formula I, ##STR00390## and at least one compound of the formula IA ##STR00391## in which R.sup.1, R.sup.1*, R.sup.1A and R.sup.A1* each, independently of one another, denote an alkyl or alkoxy radical having 1 to 15 C atoms, where one or more CH.sub.2 groups in these radicals are optionally replaced, independently of one another, by CC, CF.sub.2O, CHCH, ##STR00392## O, COO, OCO in such a way that O atoms are not linked directly to one another, and in which one or more H atoms are optionally replaced by halogen, and L.sup.1 and L.sup.2 each, independently of one another, denote F, Cl, CF.sub.3 or CHF.sub.2.

2. A liquid-crystalline medium according to claim 1, wherein the medium comprises at least one compound of the formula I-1 to I-10, ##STR00393## in which alkyl and alkyl* each, independently of one another, denote a straight-chain alkyl radical having 1-6 C atoms, alkenyl and alkenyl* each, independently of one another, denote a straight-chain alkenyl radical having 2-6 C atoms, alkoxy and alkoxy* each, independently of one another, denote a straight-chain alkoxy radical having 1-6 C atoms, and L.sup.1 and L.sup.2 each, independently of one another, denote F or Cl.

3. A liquid-crystalline medium according to claim 1, wherein the medium comprises at least compound of the formulae IA-1 to I-8: ##STR00394##

4. A liquid-crystalline medium according to claim 1, wherein the medium contains two or more compounds of the formula IA.

5. A liquid-crystalline medium according to claim 1, wherein the medium contains three or more compounds of the formula IA.

6. A liquid-crystalline medium according to claim 1, which additionally comprises one or more compounds selected from the group of the compounds of the formulae IIA, IIB and IIC, ##STR00395## in which R.sup.2A, R.sup.2B and R.sup.2C each, independently of one another, denote H, or an alkyl or alkenyl radical having 1 to 15 C atoms which is unsubstituted, monosubstituted by CN or CF.sub.3 or at least monosubstituted by halogen, where one or more CH.sub.2 groups in these radicals are optionally replaced by O, S, ##STR00396## CC, CF.sub.2O, OCF.sub.2, OCO or OCO in such a way that O atoms are not linked directly to one another, L.sup.1-4 each, independently of one another, denote F or Cl, Z.sup.2 and Z.sup.2 each, independently of one another, denote a single bond, CH.sub.2CH.sub.2, CHCH, CF.sub.2O, OCF.sub.2, CH.sub.2O, OCH.sub.2, COO, OCO, C.sub.2F.sub.4, CFCF, or CHCHCH.sub.2O, p denotes 1 or 2, q denotes 0 or 1, and v denotes 1 to 6.

7. A liquid-crystalline medium according to claim 1, which additionally comprises one or more compounds of the formula III, ##STR00397## in which R.sup.31 and R.sup.32 each, independently of one another, denote a straight-chain alkyl, alkoxyalkyl or alkoxy radical having 1 to 12 C atoms, ##STR00398## denotes ##STR00399## and Z.sup.3 denotes a single bond, CH.sub.2CH.sub.2, CHCH, CF.sub.2O, OCF.sub.2, CH.sub.2O, OCH.sub.2, COO, OCO, C.sub.2F.sub.4, C.sub.4H.sub.9 or CFCF.

8. A liquid-crystalline medium according to claim 1, wherein the medium additionally comprises at least one compound of the formulae L-1 to L-11, ##STR00400## ##STR00401## in which R, R.sup.1 and R.sup.2 each, independently of one another, denote H, or an alkyl or alkenyl radical having 1 to 15 C atoms which is unsubstituted, monosubstituted by CN or CF.sub.3 or at least monosubstituted by halogen, where one or more CH.sub.2 groups in these radicals are optionally replaced by O, S, ##STR00402## CC, CF.sub.2O, OCF.sub.2, OCO or OCO in such a way that O atoms are not linked directly to one another, (O) denotes a single bond or an O atom, alkyl denotes an alkyl radical having 1-6 C atoms, and s denotes 1 or 2.

9. A liquid-crystalline medium according to claim 1, wherein the medium additionally comprises one or more terphenyls of the formulae T-1 to T-21, ##STR00403## ##STR00404## ##STR00405## in which R denotes a straight-chain alkyl or alkoxy radical having 1-7 C atoms, (O) denotes a single bond or an O atom, m denotes 1-6, and n denotes 1-4.

10. A liquid-crystalline medium according to claim 1, wherein the medium additionally comprises one or more compounds of the formulae O-1 to O-16, ##STR00406## ##STR00407## in which R.sup.1 and R.sup.2 each, independently of one another, denote H, or an alkyl or alkenyl radical having 1 to 15 C atoms which is unsubstituted, monosubstituted by CN or CF.sub.3 or at least monosubstituted by halogen, where one or more CH.sub.2 groups in these radicals are optionally replaced by O, S, ##STR00408## CC, CF.sub.2O, OCF.sub.2, OCO or OCO in such a way that O atoms are not linked directly to one another.

11. A liquid-crystalline medium according to claim 1, wherein the medium additionally comprises one or more compounds selected from the following group of two ring compounds: ##STR00409##

12. A liquid-crystalline medium according to claim 1, wherein the medium additionally comprises one or more indane compounds of the formula In, ##STR00410## In in which R.sup.11, R.sup.12, R.sup.13 independently denote a straight-chain alkyl, alkoxy, alkoxyalkyl or alkenyl radical having 1-5 C atoms, R.sup.12 and R.sup.13 optionally also denote halogen, ##STR00411## denotes ##STR00412## and i denotes 0, 1 or 2.

13. A liquid-crystalline medium according to claim 1, wherein the medium additionally comprises one or more compounds selected from the group of compounds of the formulae BC, CR, PH-1, PH-2, BF and BS, ##STR00413## in which R.sup.B1, R.sup.B2, R.sup.CR1, R.sup.CR2, R.sup.1, R.sup.2 each, independently of one another, denote H, or an alkyl or alkenyl radical having 1 to 15 C atoms which is unsubstituted, monosubstituted by CN or CF.sub.3 or at least monosubstituted by halogen, where one or more CH.sub.2 groups in these radicals are optionally replaced by O, S, ##STR00414## CC, CF.sub.2O, OCF.sub.2, OCO or OCO in such a way that O atoms are not linked directly to one another, c denotes 0, 1 or 2, and d denotes 1 or 2.

14. A liquid-crystalline medium according to claim 1, wherein the proportion of compounds of the formula I in the mixture as a whole is 1% by weight.

15. A process for the preparation of a liquid-crystalline medium according to claim 1, comprising mixing at least one compound of the formula I and at least one compound of the formula IA with at least one further liquid-crystalline compound, and optionally adding additives.

16. An electro-optical display comprising a liquid-crystalline medium according to claim 1.

17. An electro-optical display having active-matrix addressing, which contains, as dielectric, a liquid-crystalline medium according to claim 1.

18. An electro-optical display which contains, as dielectric, a liquid-crystalline medium according to claim 1, and is a passive matrix display.

19. Electro-optical display according to claim 17, which is a VA, PSA, PS-VA, PVA, MVA, PM-VA, PALC, FFS, UB-FFS, PS-FFS, IPS or PS-IFS display.

20. A liquid-crystalline medium according to claim 2, wherein the medium comprises at least compound of the formulae IA-1 to I-8: ##STR00415##

Description

WORKING EXAMPLES

[0262] The following examples are intended to explain the invention without restricting it. In the examples, m.p. denotes the melting point and C denotes the clearing point of a liquid-crystalline substance in degrees Celsius; boiling points are denoted by b.p. Furthermore:

[0263] C denotes crystalline solid state, S denotes smectic phase (the index denotes the phase type), N denotes nematic state, Ch denotes cholesteric phase, I denotes isotropic phase, T.sub.g denotes glass transition temperature. The number between two symbols indicates the conversion temperature in degrees Celsius.

[0264] The host mixture used for determination of the optical anisotropy n of the compounds of the formula I is the commercial mixture ZLI-4792 (Merck KGaA). The dielectric anisotropy is determined using commercial mixture ZLI-2857. The physical data of the compound to be investigated are obtained from the change in the dielectric constants of the host mixture after addition of the compound to be investigated and extrapolation to 100% of the compound employed. In general, 10% of the compound to be investigated are dissolved in the host mixture, depending on the solubility.

[0265] Unless indicated otherwise, parts or percent data denote parts by weight or percent by weight.

[0266] Above and below, [0267] V.sub.0 denotes the threshold voltage, capacitive [V] at 20 C. [0268] n denotes the optical anisotropy measured at 20 C. and 589 nm [0269] denotes the dielectric anisotropy at 20 C. and 1 kHz [0270] cl.p. denotes the clearing point [ C.] [0271] K.sub.1 denotes the elastic constant, splay deformation at 20 C. [pN] [0272] K.sub.3 denotes the elastic constant, bend deformation at 20 C. [pN] [0273] .sub.1 denotes the rotational viscosity measured at 20 C. [mPa.Math.s], determined by the rotation method in a magnetic field [0274] LTS denotes the low-temperature stability (nematic phase), determined in test cells

[0275] The display used for measurement of the threshold voltage has two plane-parallel outer plates at a separation of 20 m and electrode layers with overlying alignment layers of SE-1211 (Nissan Chemicals) on the insides of the outer plates, which effect a homeotropic alignment of the liquid crystals.

[0276] All concentrations in this application relate to the corresponding mixture or mixture component, unless explicitly indicated otherwise. All physical properties are determined as described in Merck Liquid Crystals, Physical Properties of Liquid Crystals, status November 1997, Merck KGaA, Germany, and apply for a temperature of 20 C., unless explicitly indicated otherwise.

MIXTURE EXAMPLES

Example M1

[0277]

TABLE-US-00008 Y4OO4 12.00% Clearing point [ C.]: 100 CCY-3-O1 5.00% n [589 nm, 20 C.]: 0.0951 CCY-3-O2 6.00% [1 kHz, 20 C.]: 4.8 CCY-3-O3 6.00% .sub. [1 kHz, 20 C.]: 4.1 CCY-4-O2 6.00% .sub. [1 kHz, 20 C.]: 8.9 CPY-2-O2 8.00% K.sub.3 [pN, 20 C.]: 15.3 CPY-3-O2 8.00% K.sub.3/K.sub.1 [20 C.]: 0.99 CC-4-V 18.00% .sub.1 [mPa .Math. s, 20 C.]: 199 CC-5-V 5.00% V.sub.0 [20 C., V]: 1.88 CH-33 3.00% CH-35 3.00% CH-43 3.00% CH-45 3.00% CCPC-33 4.00% CCPC-34 4.00% B2OO5 6.00%

Example M2

[0278]

TABLE-US-00009 Y4OO4 15.00% Clearing point [ C.]: 101 CY-3-O4 15.50% n [589 nm, 20 C.]: 0.0976 CCY-3-O2 6.50% [1 kHz, 20 C.]: 5.7 CCY-3-O3 6.50% .sub. [1 kHz, 20 C.]: 4.4 CCY-4-O2 6.50% .sub. [1 kHz, 20 C.]: 10.1 CCY-5-O2 5.50% K.sub.3 [pN, 20 C.]: 16.9 CPY-2-O2 8.00% K.sub.3/K.sub.1 [20 C.]: 1.11 CPY-3-O2 8.00% .sub.1 [mPa .Math. s, 20 C.]: 299 CC-4-V 4.50% V.sub.0 [20 C., V]: 1.81 CH-33 3.00% CH-35 3.00% CH-43 3.00% CCPC-33 5.00% CCPC-34 5.00% CCPC-35 5.00%

Example M3

[0279]

TABLE-US-00010 Y4OO4 13.00% Clearing point [ C.]: 100 CY-3-O2 6.50% n [589 nm, 20 C.]: 0.0853 CY-3-O4 10.00% [1 kHz, 20 C.]: 4.0 CCY-3-O2 5.50% .sub. [1 kHz, 20 C.]: 3.9 CCY-3-O3 5.50% .sub. [1 kHz, 20 C.]: 7.9 CCY-4-O2 5.00% K.sub.3 [pN, 20 C.]: 16.9 CCY-5-O2 5.00% K.sub.3/K.sub.1 [20 C.]: 1.12 CPY-3-O2 3.50% .sub.1 [mPa .Math. s, 20 C.]: 207 CC-4-V 12.00% V.sub.0 [20 C., V]: 2.16 CCPV2-1 10.00% CH-33 3.00% CH-35 3.00% CH-43 3.00% CCPC-33 5.00% CCPC-34 5.00% CCPC-35 5.00%

Example M4

[0280]

TABLE-US-00011 Y4OO4 12.00% Clearing point [ C.]: 100 CY-3-O4 20.00% n [589 nm, 20 C.]: 0.0860 CY-5-O4 3.00% [1 kHz, 20 C.]: 5.2 CCY-2-1 8.00% .sub. [1 kHz, 20 C.]: 4.2 CCY-3-1 8.00% .sub. [1 kHz, 20 C.]: 9.4 CCY-3-O2 5.50% K.sub.3 [pN, 20 C.]: 16.6 CCY-3-O3 5.50% K.sub.3/K.sub.1 [20 C.]: 1.10 CCY-4-O2 5.50% .sub.1 [mPa .Math. s, 20 C.]: 310 CCY-5-O2 5.50% V.sub.0 [20 C., V]: 1.89 CH-33 3.00% CH-35 3.00% CH-43 3.00% CH-45 3.00% CCPC-33 5.00% CCPC-34 5.00% CCPC-35 5.00%

Example M5

[0281]

TABLE-US-00012 Y4OO4 12.50% Clearing point [ C.]: 105 CY-3-O4 5.00% n [589 nm, 20 C.]: 0.0868 CY-5-O4 18.00% [1 kHz, 20 C.]: 5.4 CCY-3-O1 4.00% .sub. [1 kHz, 20 C.]: 4.2 CCY-3-O2 6.00% .sub. [1 kHz, 20 C.]: 9.6 CCY-3-O3 6.00% K.sub.3 [pN, 20 C.]: 16.5 CCY-4-O2 6.00% K.sub.3/K.sub.1 [20 C.]: 0.99 CCY-5-O2 6.00% V.sub.0 [20 C., V]: 1.85 CPY-3-O2 4.50% CH-33 4.00% CH-35 4.00% CH-43 4.00% CH-45 4.00% CCOC-3-3 2.00% CCOC-4-3 2.00% CCPC-33 4.00% CCPC-34 4.00% CCPC-35 4.00%

Example M6

[0282]

TABLE-US-00013 Y4OO4 10.00% Clearing point [ C.]: 90 CY-3-O4 20.00% n [589 nm, 20 C.]: 0.0826 CY-5-O4 16.50% [1 kHz, 20 C.]: 5.4 CCY-3-O2 6.00% .sub. [1 kHz, 20 C.]: 4.2 CCY-3-O3 6.00% .sub. [1 kHz, 20 C.]: 9.6 CCY-4-O2 6.00% K.sub.3 [pN, 20 C.]: 15.0 CCY-5-O2 4.50% K.sub.3/K.sub.1 [20 C.]: 1.03 CH-33 4.00% .sub.1 [mPa .Math. s, 20 C.]: 289 CH-35 4.00% V.sub.0 [20 C., V]: 1.76 CH-43 4.00% CH-45 4.00% CCPC-33 5.00% CCPC-34 5.00% CCPC-35 5.00%

Example M7

[0283]

TABLE-US-00014 Y4OO4 11.00% Clearing point [ C.]: 92 CY-3-O2 15.00% n [589 nm, 20 C.]: 0.0921 CY-3-O4 15.00% [1 kHz, 20 C.]: 6.1 CCY-2-1 3.50% .sub. [1 kHz, 20 C.]: 4.5 CCY-3-O1 5.00% .sub. [1 kHz, 20 C.]: 10.6 CCY-3-O2 5.50% K.sub.3 [pN, 20 C.]: 16.0 CCY-3-O3 5.50% K.sub.3/K.sub.1 [20 C.]: 1.14 CCY-4-O2 5.50% .sub.1 [mPa .Math. s, 20 C.]: 300 CLY-3-O2 6.00% V.sub.0 [20 C., V]: 1.71 CPY-2-O2 4.00% CH-33 3.00% CH-35 3.00% CH-43 3.00% CCPC-33 5.00% CCPC-34 5.00% CCPC-35 5.00%

Example M8

[0284]

TABLE-US-00015 Y4OO4 15.00% Clearing point [ C.]: 95 CY-3-O4 3.00% n [589 nm, 20 C.]: 0.0814 CY-5-O4 20.00% [1 kHz, 20 C.]: 5.5 CCY-3-O1 6.00% .sub. [1 kHz, 20 C.]: 4.3 CCY-3-O2 6.00% .sub. [1 kHz, 20 C.]: 9.8 CCY-3-O3 6.00% K.sub.3 [pN, 20 C.]: 15.3 CCY-4-O2 6.00% K.sub.3/K.sub.1 [20 C.]: 1.01 CCY-5-O2 6.00% .sub.1 [mPa .Math. s, 20 C.]: 294 CH-33 4.00% V.sub.0 [20 C., V]: 1.77 CH-35 4.00% CH-43 4.00% CH-45 4.00% CCOC-3-3 2.00% CCOC-4-3 2.00% CCPC-33 4.00% CCPC-34 4.00% CCPC-35 4.00%

Example M9

[0285]

TABLE-US-00016 Y4OO4 15.00% Clearing point [ C.]: 96 CY-3-O4 4.00% n [589 nm, 20 C.]: 0.0796 CY-5-O4 16.00% [1 kHz, 20 C.]: 5.1 CCY-3-O1 5.00% .sub. [1 kHz, 20 C.]: 4.2 CCY-3-O2 6.00% .sub. [1 kHz, 20 C.]: 9.3 CCY-3-O3 6.00% K.sub.3 [pN, 20 C.]: 15.5 CCY-4-O2 6.00% K.sub.3/K.sub.1 [20 C.]: 1.00 CCY-5-O2 6.00% .sub.1 [mPa .Math. s, 20 C.]: 272 CC-5-V 3.50% V.sub.0 [20 C., V]: 1.84 CH-33 4.00% CH-35 4.00% CH-43 4.00% CH-45 4.00% CCOC-3-3 2.50% CCOC-4-3 2.50% CCPC-33 4.00% CCPC-34 3.50% CCPC-35 4.00%

Example M10

[0286]

TABLE-US-00017 Y4OO4 15.00% Clearing point [ C.]: 96 CY-3-O2 3.00% n [589 nm, 20 C.]: 0.0808 CY-5-O4 18.00% [1 kHz, 20 C.]: 5.2 CCY-3-O1 5.50% .sub. [1 kHz, 20 C.]: 4.3 CCY-3-O2 6.00% .sub. [1 kHz, 20 C.]: 9.5 CCY-3-O3 6.00% K.sub.3 [pN, 20 C.]: 15.4 CCY-4-O2 6.00% K.sub.3/K.sub.1 [20 C.]: 0.99 CCY-5-O2 6.00% .sub.1 [mPa .Math. s, 20 C.]: 277 CC-5-V 2.50% V.sub.0 [20 C., V]: 1.81 CH-33 4.00% CH-35 4.00% CH-43 4.00% CH-45 4.00% CCOC-3-3 2.00% CCOC-4-3 2.00% CCPC-33 4.00% CCPC-34 4.00% CCPC-35 4.00%

Example M11

[0287]

TABLE-US-00018 Y4OO4 12.00% Clearing point [ C.]: 100 CY-3-O4 4.00% n [589 nm, 20 C.]: 0.0818 CY-5-O4 20.00% [1 kHz, 20 C.]: 5.3 CCY-3-O1 6.00% .sub. [1 kHz, 20 C.]: 4.1 CCY-3-O2 6.50% .sub. [1 kHz, 20 C.]: 9.4 CCY-3-O3 6.50% K.sub.3 [pN, 20 C.]: 15.4 CCY-4-O2 6.50% K.sub.3/K.sub.1 [20 C.]: 0.94 CCY-5-O2 6.50% .sub.1 [mPa .Math. s, 20 C.]: 304 CH-33 4.00% V.sub.0 [20 C., V]: 1.80 CH-35 4.00% CH-43 4.00% CH-45 4.00% CCOC-3-3 4.00% CCOC-4-3 4.00% CCPC-33 4.00% CCPC-34 4.00%

Example M12

[0288]

TABLE-US-00019 Y4OO4 7.00% Clearing point [ C.]: 100 CY-3-O2 10.00% n [589 nm, 20 C.]: 0.0949 CY-3-O4 18.00% [1 kHz, 20 C.]: 5.2 CCY-3-O2 6.50% .sub. [1 kHz, 20 C.]: 4.0 CCY-3-O3 6.50% .sub. [1 kHz, 20 C.]: 9.2 CCY-4-O2 6.50% K.sub.3 [pN, 20 C.]: 16.8 CPY-2-O2 8.50% K.sub.3/K.sub.1 [20 C.]: 1.12 CPY-3-O2 5.00% .sub.1 [mPa .Math. s, 20 C.]: 270 CC-5-V 9.00% V.sub.0 [20 C., V]: 1.91 CH-33 3.00% CH-35 3.00% CH-43 3.00% CCPC-33 5.00% CCPC-34 4.50% CCPC-35 4.50%

Example M13

[0289]

TABLE-US-00020 Y4OO4 15.00% Clearing point [ C.]: 103 COY-2-O2 8.00% COY-3-O2 7.50% CCOY-2-O2 13.00% CCOY-3-O2 6.50% CCOY-4-O2 5.50% CPY-2-O2 8.00% CPY-3-O2 8.00% CC-4-V 4.50% CH-33 3.00% CH-35 3.00% CH-43 3.00% CCPC-33 5.00% CCPC-34 5.00% CCPC-35 5.00%

Example M14

[0290]

TABLE-US-00021 Y4OO4 11.00% Clearing point [ C.]: 90 CY-3-O4 12.00% n [589 nm, 20 C.]: 0.0706 CCY-3-O1 5.00% [1 kHz, 20 C.]: 4.0 CCY-3-O2 6.00% .sub. [1 kHz, 20 C.]: 3.9 CCY-3-O3 6.00% .sub. [1 kHz, 20 C.]: 7.9 CCY-4-O2 6.00% K.sub.3 [pN, 20 C.]: 14.0 CCY-5-O2 6.00% K.sub.3/K.sub.1 [20 C.]: 1.04 CCH-301 18.00% .sub.1 [mPa .Math. s, 20 C.]: 190 CH-33 4.00% V.sub.0 [20 C., V]: 1.99 CH-35 4.00% CH-43 4.00% CH-45 4.00% CCOC-3-3 5.00% CCOC-4-3 5.00% CCPC-33 4.00%

Examples M15 to M20

[0291] In a preferred embodiment, the liquid-crystalline mixtures according to the Examples M1, M2, M3, M10, M12 and M13 are each stabilized by adding 300 ppm of the compound of the formula

##STR00389##

[0292] The preceding examples can be repeated with similar success by substituting the generically or specifically described reactants and/or operating conditions of this invention for those used in the preceding examples.

[0293] From the foregoing description, one skilled in the art can easily ascertain the essential characteristics of this invention and, without departing from the spirit and scope thereof, can make various changes and modifications of the invention to adapt it to various usages and conditions.