LIQUID-CRYSTALLINE MEDIUM

Abstract

The invention relates to a liquid-crystalline medium which comprises at least one compound of the formula I,

##STR00001##

in which R.sup.1, R.sup.1*, rings A and B, Z.sup.1, L.sup.1, L.sup.2, a and b have the meanings indicated in Claim 1, and to the use thereof for an active-matrix display, in particular based on the VA, PSA, PS-VA, PALC, FFS, PS-FFS, IPS or PS-IPS effect.

Claims

1-19. (canceled)

20. Liquid-crystalline medium based on a mixture of polar compounds, which comprises: at least one compound of the formula I, ##STR00341## in which R.sup.1 and R.sup.1* each, independently of one another, denote an alkyl or alkoxy radical having 1 to 15 C atoms, where, in addition, one or more CH.sub.2 groups in these radicals are optionally replaced, independently of one another, by C?C, CF.sub.2O, CH?CH, ##STR00342## O, COO, OCO in such a way that O atoms are not linked directly to one another, and in which, in addition, one or more H atoms are optionally replaced by halogen, Z.sup.1 denotes CH.sub.2O or OCH.sub.2 a denotes 0, 1 or 2 b denotes 1 or 2, ##STR00343## each, independently of one another, denote ##STR00344## and L.sup.1 and L.sup.2 each, independently of one another, denote F, Cl, CF.sub.3, OCF.sub.3 or CHF.sub.2; and one or more polymerizable compounds selected from the compounds of the formula I* or one or more polymers obtained by polymerizing compounds selected from the compounds of the formula I*
R.sup.a-A.sup.1-(Z.sup.1-A.sup.2).sub.m-R.sup.b I* in which the individual radicals have the following meanings: R.sup.a and R.sup.b each, independently of one another, denote P, P-Sp-, H, halogen, SF.sub.5, NO.sub.2, a carbon group or hydrocarbon group, where at least one of the radicals R.sup.a and R.sup.b denotes or contains a group P or P-Sp-, P on each occurrence, identically or differently, denotes a polymerisable group, Sp on each occurrence, identically or differently, denotes a spacer group or a single bond, A.sup.1 and A.sup.2 each, independently of one another, denote an aromatic, heteroaromatic, alicyclic or heterocyclic group, which may also contain fused rings, and which may also be mono- or polysubstituted by L, L denotes P-Sp-, H, OH, CH.sub.2OH, halogen, SF.sub.5, NO.sub.2, a carbon group or hydrocarbon group, Z.sup.1 on each occurrence, identically or differently, denotes O, S, CO, COO, OCO, OCOO, OCH.sub.2, CH.sub.2O, SCH.sub.2, CH.sub.2S, CF.sub.2O, OCF.sub.2, CF.sub.2S, SCF.sub.2, (CH.sub.2).sub.n1, CF.sub.2CH.sub.2, CH.sub.2CF.sub.2, (CF.sub.2).sub.n1, CH?CH, CF?CF, C?C, CH?CHCOO, OCOCH?CH, CR.sup.0R.sup.00 or a single bond, R.sup.0 and R.sup.00 each, independently of one another, denote H or alkyl having 1 to 12 C atoms, m denotes 0, 1, 2, 3 or 4, and n1 denotes 1, 2, 3 or 4.

21. Liquid-crystalline medium based on a mixture of polar compounds, which comprises: at least one compound of the formula I, ##STR00345## in which R.sup.1 and R.sup.1* each, independently of one another, denote an alkyl or alkoxy radical having 1 to 15 C atoms, where, in addition, one or more CH.sub.2 groups in these radicals are optionally replaced, independently of one another, by C?C, CF.sub.2O, CH?CH, ##STR00346## O, COO, OCO in such a way that O atoms are not linked directly to one another, and in which, in addition, one or more H atoms are optionally replaced by halogen, Z.sup.1 denotes CH.sub.2O or OCH.sub.2 a denotes 0, 1 or 2 b denotes 1 or 2, ##STR00347## each, independently of one another, denote ##STR00348## and L.sup.1 and L.sup.2 each, independently of one another, denote F, Cl, CF.sub.3, OCF.sub.3 or CHF.sub.2; and one or more polymerizable compounds selected from the reactive mesogen compounds of formulae RM-1 to RM-74 or one or more polymers obtained by polymerizing compounds selected from the compounds of the formulae RM-1 to RM-74: ##STR00349## ##STR00350## ##STR00351## ##STR00352## ##STR00353## ##STR00354## ##STR00355##

22. Liquid-crystalline medium based on a mixture of polar compounds, which comprises: at least one compound of the formula I, ##STR00356## in which R.sup.1 and R.sup.1* each, independently of one another, denote an alkyl or alkoxy radical having 1 to 15 C atoms, where, in addition, one or more CH.sub.2 groups in these radicals are optionally replaced, independently of one another, by C?C, CF.sub.2O, CH?CH, ##STR00357## O, COO, OCO in such a way that O atoms are not linked directly to one another, and in which, in addition, one or more H atoms are optionally replaced by halogen, Z.sup.1 denotes CH.sub.2O or OCH.sub.2 a denotes 0, 1 or 2 b denotes 1 or 2, ##STR00358## each, independently of one another, denote ##STR00359## and L.sup.1 and L.sup.2 each, independently of one another, denote F, Cl, CF.sub.3, OCF.sub.3 or CHF.sub.2; and which additionally comprises one or more compounds selected from the group of the compounds of the formulae III, L1-L12, T1-T21, O1-O16 and In: ##STR00360## 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, and ##STR00361## denotes ##STR00362## Z.sup.3 denotes a single bond, CH.sub.2CH.sub.2, CH?CH, CF.sub.2O, OCF.sub.2, CH.sub.2O, OCH.sub.2, COO, OCO, C.sub.2F.sub.4, C.sub.4H.sub.8, or CF?CF, ##STR00363## ##STR00364## in which R, R.sup.1 and R.sup.2 each, independently of one another, denote H, an alkyl radical having up to 15 C atoms which is unsubstituted, monosubstituted by CN or CF.sub.3 or at least monosubstituted by halogen, where, in addition, one or more CH.sub.2 groups in these radicals are optionally replaced by O, S, ##STR00365## C?C, CF.sub.2O, OCF.sub.2, OCO or OCO in such a way that O atoms are not linked directly to one another, alkyl denotes an alkyl radical having 1-6 C atoms, and s denotes 1 or 2, ##STR00366## ##STR00367## ##STR00368## in which R denotes a straight-chain alkyl or alkoxy radical having 1-7 C atoms, and m denotes 1-6, ##STR00369## ##STR00370## in which R.sup.1 and R.sup.2 each, independently of one another, denote H, an alkyl radical having up to 15 C atoms which is unsubstituted, monosubstituted by CN or CF.sub.3 or at least monosubstituted by halogen, where, in addition, one or more CH.sub.2 groups in these radicals are optionally replaced by O, S, ##STR00371## C?, CF.sub.2O, OCF.sub.2, OCO or OCO in such a way that O atoms are not linked directly to one another, ##STR00372## In in which R.sup.11, R.sup.12, R.sup.13 denote a straight-chain alkyl, alkoxy, alkoxyalkyl or alkenyl radical having 1-5 C atoms, R.sup.12 and R.sup.13 additionally also denote halogen or hydrogen, ##STR00373## denotes ##STR00374## and i denotes 0, 1 or 2.

23. Liquid-crystalline medium based on a mixture of polar compounds, which exhibits the following combination of properties: a clearing point ?70? C.; threshold voltage from 1.7 V to 3.0 V; voltage holding ratio (VHR after 15 min. exposure to UVA measured after 5 min. at 100? C. at 1V, 60 Hz, 64 ?s pulse) is 97.6% or more; low-temperature stability at ?20? C. and ?30? C.; rotational viscosity at 20? C.?165 mPa.Math.s; optical anisotropy ?n at 20? C. and 589 nm of 0.07 to 0.16; and dielectric anisotropy ?? at 20? C. and 1 kHz of ?0.5 to ?8.0; and which comprises: at least one compound of the formula I, ##STR00375## in which R.sup.1 and R.sup.1* each, independently of one another, denote an alkyl or alkoxy radical having 1 to 15 C atoms, where, in addition, one or more CH.sub.2 groups in these radicals are optionally replaced, independently of one another, by C?C, CF.sub.2O, CH?CH, ##STR00376## O, COO, OCO in such a way that O atoms are not linked directly to one another, and in which, in addition, one or more H atoms are optionally replaced by halogen, Z.sup.1 denotes CH.sub.2O or OCH.sub.2 a denotes 0, 1 or 2 b denotes 1 or 2, ##STR00377## each, independently of one another, denote ##STR00378## and L.sup.1 and L.sup.2 each, independently of one another, denote F, Cl, CF.sub.3, OCF.sub.3 or CHF.sub.2.

24. A PS-VA or PSA display having a low pre-tilt angle of ?85? which comprises a liquid-crystalline medium based on a mixture of polar compounds, including one or more polymerizable reactive mesogen compounds and at least one compound of the formula I and not containing a photoinitiator: ##STR00379## in which R.sup.1 and R.sup.1* each, independently of one another, denote an alkyl or alkoxy radical having 1 to 15 C atoms, where, in addition, one or more CH.sub.2 groups in these radicals are optionally replaced, independently of one another, by C?C, CF.sub.2O, CH?CH, ##STR00380## O, COO, OCO in such a way that O atoms are not linked directly to one another, and in which, in addition, one or more H atoms are optionally replaced by halogen, Z.sup.1 denotes CH.sub.2O or OCH.sub.2 a denotes 0, 1 or 2 b denotes 1 or 2, ##STR00381## each, independently of one another, denote ##STR00382## and L.sup.1 and L.sup.2 each, independently of one another, denote F, Cl, CF.sub.3, OCF.sub.3 or CHF.sub.2.

25. A liquid-crystalline medium according to claim 20, further comprising one or more compounds selected from the group of the compounds of the formulae IIA, IIB and IIC, ##STR00383## in which R.sup.2A, R.sup.2B and R.sup.2C each, independently of one another, denote H, an alkyl radical having up to 15 C atoms which is unsubstituted, monosubstituted by CN or CF.sub.3 or at least monosubstituted by halogen, where, in addition, one or more CH.sub.2 groups in these radicals may be replaced by O, S, ##STR00384## C?C, 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, Cl, CF.sub.3 or CHF.sub.2, Z.sup.2 and Z.sup.2 each, independently of one another, denote a single bond, CH.sub.2CH.sub.2, CH?CH, CF.sub.2O, OCF.sub.2, COO, OCO, C.sub.2F.sub.4, CF?CF, CH?CHCH.sub.2O, p denotes 1 or 2, q denotes 0 or 1, and v denotes 1 to 6.

26. A liquid-crystalline medium according to claim 21, further comprising one or more compounds selected from the group of the compounds of the formulae IIA, IIB and IIC, ##STR00385## in which R.sup.2A, R.sup.2B and R.sup.2C each, independently of one another, denote H, an alkyl radical having up to 15 C atoms which is unsubstituted, monosubstituted by CN or CF.sub.3 or at least monosubstituted by halogen, where, in addition, one or more CH.sub.2 groups in these radicals may be replaced by O, S, ##STR00386## C?C, 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, Cl, CF.sub.3 or CHF.sub.2, Z.sup.2 and Z.sup.2 each, independently of one another, denote a single bond, CH.sub.2CH.sub.2, CH?CH, CF.sub.2O, OCF.sub.2, COO, OCO, C.sub.2F.sub.4, CF?CF, CH?CHCH.sub.2O, p denotes 1 or 2, q denotes 0 or 1, and v denotes 1 to 6.

27. A liquid-crystalline medium according to claim 22, further comprising one or more compounds selected from the group of the compounds of the formulae IIA, IIB and IIC, ##STR00387## in which R.sup.2A, R.sup.2B and R.sup.2C each, independently of one another, denote H, an alkyl radical having up to 15 C atoms which is unsubstituted, monosubstituted by CN or CF.sub.3 or at least monosubstituted by halogen, where, in addition, one or more CH.sub.2 groups in these radicals may be replaced by O, S, ##STR00388## C?C, 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, Cl, CF.sub.3 or CHF.sub.2, Z.sup.2 and Z.sup.2 each, independently of one another, denote a single bond, CH.sub.2CH.sub.2, CH?CH, CF.sub.2O, OCF.sub.2, COO, OCO, C.sub.2F.sub.4, CF?CF, CH?CHCH.sub.2O, p denotes 1 or 2, q denotes 0 or 1, and v denotes 1 to 6.

28. A liquid-crystalline medium according to claim 23, further comprising one or more compounds selected from the group of the compounds of the formulae IIA, IIB and IIC, ##STR00389## in which R.sup.2A, R.sup.2B and R.sup.2C each, independently of one another, denote H, an alkyl radical having up to 15 C atoms which is unsubstituted, monosubstituted by CN or CF.sub.3 or at least monosubstituted by halogen, where, in addition, one or more CH.sub.2 groups in these radicals may be replaced by O, S, ##STR00390## C?C, 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, Cl, CF.sub.3 or CHF.sub.2, Z.sup.2 and Z.sup.2 each, independently of one another, denote a single bond, CH.sub.2CH.sub.2, CH?CH, CF.sub.2O, OCF.sub.2, COO, OCO, C.sub.2F.sub.4, CF?CF, CH?CHCH.sub.2O, p denotes 1 or 2, q denotes 0 or 1, and v denotes 1 to 6.

29. A display according to claim 24, wherein the liquid-crystalline medium further comprising one or more compounds selected from the group of the compounds of the formulae IIA, IIB and IIC, ##STR00391## in which R.sup.2A, R.sup.2B and R.sup.2C each, independently of one another, denote H, an alkyl radical having up to 15 C atoms which is unsubstituted, monosubstituted by CN or CF.sub.3 or at least monosubstituted by halogen, where, in addition, one or more CH.sub.2 groups in these radicals may be replaced by O, S, ##STR00392## C?C, 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, Cl, CF.sub.3 or CHF.sub.2, Z.sup.2 and Z.sup.2 each, independently of one another, denote a single bond, CH.sub.2CH.sub.2, CH?CH, CF.sub.2O, OCF.sub.2, COO, OCO, C.sub.2F.sub.4, CF?CF, CH?CHCH.sub.2O, p denotes 1 or 2, q denotes 0 or 1, and v denotes 1 to 6.

30. Liquid-crystalline medium according to claim 22, which comprises one or more compounds selected from the group of the compounds of the formula III.

31. Liquid-crystalline medium according to claim 22, which comprises one or more compounds selected from the group of the compounds of the formulae L1-L12.

32. Liquid-crystalline medium according to claim 22, which comprises one or more compounds selected from the group of the compounds of the formulae T1-T21.

33. Liquid-crystalline medium according to claim 22, which comprises one or more compounds selected from the group of the compounds of the formulae O1-O16.

34. Liquid-crystalline medium according to claim 22, which comprises one or more compounds selected from the group of the compounds of the formula In.

Description

WORKING EXAMPLES

[0428] The following examples are intended to explain the invention without restricting it.

[0429] Unless explicitly noted otherwise, all temperature values indicated in the present application, for example the melting point T(C,N), the transition from the smectic (S) phase to the nematic (N) phase T(S,N) and the clearing point T(N,I), are indicated in degrees Celsius (? C.). M.p. denotes melting point, cl.p.=clearing point. Furthermore, C=crystalline state, N=nematic phase, S=smectic phase and I=isotropic phase. The figures between these symbols represent the transition temperatures.

[0430] 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.

[0431] Unless indicated otherwise, parts or per cent data denote parts by weight or per cent by weight.

[0432] Above and below, [0433] V.sub.0 denotes threshold voltage, capacitive [V] at 20? C. [0434] n.sub.e denotes extraordinary refractive index at 20? C. and 589 nm, [0435] n.sub.o denotes ordinary refractive index at 20? C. and 589 nm, [0436] ?n denotes optical anisotropy at 20? C. and 589 nm [0437] ?.sub.? denotes dielectric susceptability perpendicular to the director at 20? C. and 1 kHz, [0438] ?.sub.? denotes dielectric susceptability parallel to the director at 20? C. and 1 kHz, [0439] ?? denotes dielectric anisotropy at 20? C. and 1 kHz [0440] cl.p., T(N,I) denotes clearing point [? C.] [0441] ?.sub.1 denotes he rotational viscosity measured at 20? C. [mPa.Math.s], determined by the rotation method in a magnetic field [0442] K.sub.1 denotes elastic constant, splay deformation at 20? C. [pN] [0443] K.sub.3 denotes elastic constant, bend deformation at 20? C. [pN] [0444] LTS denotes low-temperature stability (nematic phase), determined in test cells, [0445] HR.sub.20 denotes voltage holding ratio at 20? C. [%] and [0446] HR.sub.100 denotes voltage holding ratio at 100? C. [%].

[0447] 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.

[0448] 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.

[0449] Unless explicitly noted otherwise, all concentrations and % values (with the exception of the values for HR, contrast and transmission) in the present application are indicated in per cent by weight and relate to the corresponding mixture as a whole comprising all solid or liquid-crystalline components, without solvent.

[0450] The term threshold voltage for the present invention relates to the capacitive threshold (V.sub.0), also called the Freedericks threshold, unless explicitly indicated otherwise. In the examples, as generally usual, the optical threshold for 10% relative contrast (V.sub.10) may also be indicated.

[0451] The display used for measurement of the capacitive threshold voltage consists of two plane-parallel glass outer plates at a separation of 20 ?m, each of which has, on the inside, an electrode layer and an unrubbed polyimide alignment layer on top, which effect a homeotropic edge alignment of the liquid-crystal molecules.

[0452] The display or test cell used for measurement of the tilt angles consists of two plane-parallel glass outer plates at a separation of 4 ?m, each of which has, on the inside, an electrode layer and a polyimide alignment layer on top, where the two polyimide layers are rubbed antiparallel to one another and effect a homeotropic edge alignment of the liquid-crystal molecules.

[0453] The polymerisable compounds are polymerised in the display or test cell by irradiation with UVA light for a pre-specified time, with a voltage simultaneously being applied to the display (usually 10 V to 30 V alternating current, 1 kHz). In the examples, unless indicated otherwise, a metal halide lamp and an intensity of 100 mW/cm.sup.2 are used for the polymerisation, and the intensity is measured using a standard UVA meter (Hoenle high end UV meter with UVA sensor).

[0454] The tilt angle is determined by rotational crystal experiment (Autronic-Melchers TBA-105). A low value (i.e. a large deviation from the 90? angle) corresponds to a large tilt here.

[0455] The VHR value is measured as follows: 0.3% of a polymerisable monomeric compound is added to the LC host mixture, and the resultant mixture is introduced into VA-VHR test cells (unrubbed at 90?, VA-polyimide alignment layer, layer thickness d?6 ?m). The HR value is determined after 5 min at 100? C. before and after UV exposure at 1 V, 60 Hz, 64 ?s pulse (measuring instrument: Autronic-Melchers VHRM-105).

MIXTURE EXAMPLES

Example M1

[0456]

TABLE-US-00005 CY-3-O2 22.00% Clearing point [? C.]: 79.5 CY-5-O2 2.00% ?n [589 nm, 20? C.]: 0.0942 CCOY-3-O2 8.00% ?? [1 kHz, 20? C.]: ?3.0 CPY-2-O2 7.00% ?.sub.? [1 kHz, 20? C.]: 3.4 CPY-3-O2 10.00% K.sub.3 [pN, 20? C.]: 15.5 CCH-34 6.00% K.sub.3/K.sub.1 [20? C.]: 1.08 CCH-23 22.00% ?.sub.1 [mPa .Math. s, 20? C.]: 112 CCP-3-3 7.50% V.sub.0 [20? C., V]: 2.41 CCP-3-1 7.00% VHR (initial): 98.6% BCH-32 6.00% VHR (15 min UVA): 94.5% PCH-301 2.50% VHR (2 min UVA + 2 h suntest): 91.6%

Example M2

[0457]

TABLE-US-00006 CY-3-O2 12.00% Clearing point [? C.]: 79.5 COY-3-O2 12.00% ?n [589 nm, 20? C.]: 0.0955 CCY-3-O2 4.00% ?? [1 kHz, 20? C.]: ?3.0 CPY-2-O2 9.00% ?.sub.? [1 kHz, 20? C.]: 3.4 CPY-3-O2 10.00% K.sub.3 [pN, 20? C.]: 15.3 CCH-34 6.00% K.sub.3/K.sub.1 [20? C.]: 1.03 CCH-23 22.00% ?.sub.1 [mPa .Math. s, 20? C.]: 108 CCP-3-3 8.00% V.sub.0 [20? C., V]: 2.39 CCP-3-1 8.00% VHR (initial): 98.4% BCH-32 6.00% VHR (15 min UVA): 93.5% PCH-301 3.00% VHR (2 min UVA + 2 h suntest): 89.0%

Example M3

[0458]

TABLE-US-00007 COY-3-O2 21.00% Clearing point [? C.]: 79.5 CCY-3-O2 3.00% ?n [589 nm, 20? C.]: 0.0959 CPY-2-O2 10.00% ?? [1 kHz, 20? C.]: ?3.0 CPY-3-O2 10.00% ?.sub.? [1 kHz, 20? C.]: 3.5 CCH-34 6.00% K.sub.3 [pN, 20? C.]: 14.9 CCH-23 22.00% K.sub.3/K.sub.1 [20? C.]: 1.03 CCP-3-3 8.00% ?.sub.1 [mPa .Math. s, 20? C.]: 108 CCP-3-1 8.00% VHR (initial): 98.4% BCH-32 6.00% VHR (15 min UVA): 91.0% PCH-301 6.00% VHR (2 min UVA + 2 h suntest): 86.4%

Example M4

[0459] For the preparation of a PS-VA mixture, 0.3% of RM1 (biphenyl 4,4-dimethacrylate)

##STR00335##

[0460] is added to the liquid-crystal mixture in accordance with Example M1.

[0461] The PS-VA mixture is introduced into a cell having homeotropic alignment. After application of a voltage of 24 V, the cell is irradiated with UV light with a power of 100 mW/cm.sup.2. The following tilt angles have then become established:

TABLE-US-00008 Irradiation duration/min Tilt angle/? 0 89.4 0.5 89.1 1 87.0 2 83.4 4 79.6 6 77.1

[0462] The values measured for the holding ratio are

[0463] VHR (initial): 98.4%

[0464] VHR (15 min UVA): 97.8%

[0465] VHR (2 min UVA+2 h suntest): 97.8%.

Example M5

[0466] For the preparation of a PS-VA mixture, 0.3% of RM1 (biphenyl 4,4-dimethacrylate)

##STR00336##

[0467] is added to the liquid-crystal mixture in accordance with Example M2.

[0468] The PS-VA mixture is introduced into a cell having homeotropic alignment. After application of a voltage of 24 V, the cell is irradiated with UV light with a power of 100 mW/cm.sup.2. The following tilt angles have then become established:

TABLE-US-00009 Irradiation duration/min Tilt angle/? 0 89.4 0.5 89.0 1 86.8 2 83.5 4 79.3 6 76.9

[0469] The values measured for the holding ratio are

[0470] VHR (initial): 98.1%

[0471] VHR (15 min UVA): 97.7%

[0472] VHR (2 min UVA+2 h suntest): 97.5%.

Example M6

[0473] For the preparation of a PS-VA mixture, 0.3% of RM1 (biphenyl 4,4-dimethacrylate)

##STR00337##

[0474] is added to the liquid-crystal mixture in accordance with Example M3.

[0475] The PS-VA mixture is introduced into a cell having homeotropic alignment. After application of a voltage of 24 V, the cell is irradiated with UV light with a power of 100 mW/cm.sup.2. The following tilt angles have then become established:

TABLE-US-00010 Irradiation duration/min Tilt angle/? 0 89.3 0.5 89.0 1 86.8 2 83.2 4 78.7 6 76.5

[0476] The values measured for the holding ratio are

[0477] VHR (initial): 98.2%

[0478] VHR (15 min UVA): 97.6%

[0479] VHR (2 min UVA+2 h suntest): 97.1%.

Example M7

[0480]

TABLE-US-00011 COY-3-O2 12.00% Clearing point [? C.]: 85.5 COY-3-O4 12.00% ?n [589 nm, 20? C.]: 0.0963 CCY-3-O2 9.00% ?? [1 kHz, 20? C.]: ?4.2 CCY-3-O3 8.00% K.sub.1 [pN, 20? C.]: 13.6 CCY-4-O2 9.00% K.sub.3 [pN, 20? C.]: 15.5 CPY-2-O2 7.00% ?.sub.1 [mPa .Math. s, 20? C.]: 164 CPY-3-O2 7.00% V.sub.0 [20? C., V]: 2.04 BCH-32 6.00% CCH-34 14.00% CCH-35 6.00% PCH-301 10.00%

Example M8

[0481]

TABLE-US-00012 COY-3-O2 11.00% Clearing point [? C.]: 85.5 COY-3-O4 11.00% ?n [589 nm, 20? C.]: 0.0961 CCOY-3-O2 8.00% ?? [1 kHz, 20? C.]: ?4.2 CCY-3-O2 10.00% K.sub.1 [pN, 20? C.]: 14.1 CCY-4-O2 10.00% K.sub.3 [pN, 20? C.]: 16.5 CPY-2-O2 5.00% ?.sub.1 [mPa .Math. s, 20? C.]: 164 CPY-3-O2 7.00% V.sub.0 [20? C., V]: 2.13 BCH-32 6.00% CCH-34 14.00% CCH-35 6.00% PCH-301 12.00%

Example M9

[0482]

TABLE-US-00013 CC-3-V 38.50% Clearing point [? C.]: 74.5 CCY-4-O2 10.50% ?n [589 nm, 20? C.]: 0.1056 CPY-2-O2 11.00% ?? [1 kHz, 20? C.]: ?3.1 CPY-3-O2 11.00% K.sub.1 [pN, 20? C.]: 12.4 COY-3-O2 13.00% K.sub.3 [pN, 20? C.]: 13.7 COY-3-O4 4.00% ?.sub.1 [mPa .Math. s, 20? C.]: 98 PYP-2-4 9.00% V.sub.0 [20? C., V]: 2.19 PYP-2-3 3.00%

Example M10

[0483]

TABLE-US-00014 BCH-32 11.00% Clearing point [? C.]: 75.5 CCH-23 20.00% ?n [589 nm, 20? C.]: 0.1037 CCH-301 1.50% ?? [1 kHz, 20? C.]: ?3.2 CCH-34 6.00% K.sub.1 [pN, 20? C.]: 14.7 CCH-35 7.00% K.sub.3 [pN, 20? C.]: 14.6 CCY-3-O2 12.00% ?.sub.1 [mPa .Math. s, 20? C.]: 116 CPY-2-O2 5.00% V.sub.0 [20? C., V]: 2.24 CPY-3-O2 12.00% PY-3-O2 12.00% COY-3-O2 13.50%

Example M11

[0484] For the preparation of a PS-VA mixture, 0.3% of RM1

##STR00338##

[0485] is added to the liquid-crystal mixture in accordance with Example M10.

[0486] The PS-VA mixture is introduced into a cell having homeotropic alignment. After application of a voltage of 24 V, the cell is irradiated with UV light with a power of 100 mW/cm.sup.2. The tilt angles have then become established:

Example M12

[0487]

TABLE-US-00015 BCH-32 7.50% Clearing point [? C.]: 75.0 CC-3-V1 10.00% ?n [589 nm, 20? C.]: 0.1040 CCH-23 10.00% ?? [1 kHz, 20? C.]: ?3.1 CCH-301 3.00% K.sub.1 [pN, 20? C.]: 14.8 CCH-34 5.00% K.sub.3 [pN, 20? C.]: 15.5 CCH-35 9.00% ?.sub.1 [mPa .Math. s, 20? C.]: 111 CCY-3-O2 10.50% V.sub.0 [20? C., V]: 2.35 CPY-2-O2 7.00% CPY-3-O2 11.00% PCH-301 3.00% PY-3-O2 13.00% COY-3-O2 11.00%

Example M13

[0488] For the preparation of a PS-VA mixture, 0.3% of RM25

##STR00339##

[0489] is added to the liquid-crystal mixture in accordance with Example M12.

[0490] The PS-VA mixture is introduced into a cell having homeotropic alignment. After application of a voltage of 24 V, the cell is irradiated with UV light with a power of 100 mW/cm.sup.2. The tilt angles have then become established:

Example M14

[0491]

TABLE-US-00016 CC-3-V 39.00% Clearing point [? C.]: 76.0 CCY-3-O2 13.00% ?n [589 nm, 20? C.]: 0.1092 CCY-3-O3 2.00% ?? [1 kHz, 20? C.]: ?3.4 CPY-2-O2 11.00% K.sub.1 [pN, 20? C.]: 13.7 CPY-3-O2 12.00% K.sub.3 [pN, 20? C.]: 15.0 PY-3-O2 13.50% ?.sub.1 [mPa .Math. s, 20? C.]: 100 PYP-2-4 4.50% V.sub.0 [20? C., V]: 2.24 COY-3-O2 5.00%

Example M15

[0492]

TABLE-US-00017 COY-3-O2 16.00% Clearing point [? C.]: 81.0 CCY-3-O2 9.00% ?n [589 nm, 20? C.]: 0.0931 CPY-2-O2 5.00% ?? [1 kHz, 20? C.]: ?2.9 CPY-3-O2 10.00% K.sub.1 [pN, 20? C.]: 15.0 CCH-34 7.00% K.sub.3 [pN, 20? C.]: 15.6 CCH-23 21.00% ?.sub.1 [mPa .Math. s, 20? C.]: 108 CCP-3-3 6.00% V.sub.0 [20? C., V]: 2.42 CCP-3-1 10.00% BCH-32 6.00% Y-4O-O4 7.00% CBC-33 3.00%

Example M16

[0493]

TABLE-US-00018 COY-3-O2 5.00% Clearing point [? C.]: 75.0 CCY-3-O2 8.00% ?n [589 nm, 20? C.]: 0.1061 CLY-3-O2 8.00% ?? [1 kHz, 20? C.]: ?3.0 CPY-2-O2 7.00% K.sub.1 [pN, 20? C.]: 13.1 CPY-3-O2 10.00% K.sub.3 [pN, 20? C.]: 14.6 PYP-2-3 10.00% ?.sub.1 [mPa .Math. s, 20? C.]: 83 PYP-2-4 2.00% V.sub.0 [20? C., V]: 2.33 CC-3-V 36.00% CC-3-V1 4.00% CCP-V-1 3.00% Y-4O-O4 7.00%

Example M17

[0494]

TABLE-US-00019 COY-3-O2 5.00% Clearing point [? C.]: 75.0 CCOY-3-O2 4.00% ?n [589 nm, 20? C.]: 0.1071 CCY-3-O2 4.00% ?? [1 kHz, 20? C.]: ?3.0 CLY-3-O2 8.00% K.sub.1 [pN, 20? C.]: 13.3 CPY-2-O2 6.00% K.sub.3 [pN, 20? C.]: 14.8 CPY-3-O2 10.00% ?.sub.1 [mPa .Math. s, 20? C.]: 85 PYP-2-3 10.00% V.sub.0 [20? C., V]: 2.36 PYP-2-4 3.00% CC-3-V 34.00% CC-3-V1 6.00% CCP-V-1 3.00% Y-4O-O4 7.00%

Example M18

[0495]

TABLE-US-00020 COY-3-O2 18.00% Clearing point [? C.]: 74.0 CCY-3-O3 4.00% ?n [589 nm, 20? C.]: 0.1280 CPY-2-O2 10.00% ?? [1 kHz, 20? C.]: ?3.2 CPY-3-O2 12.00% K.sub.1 [pN, 20? C.]: 13.0 CCH-34 10.00% K.sub.3 [pN, 20? C.]: 12.9 CCH-23 19.00% ?.sub.1 [mPa .Math. s, 20? C.]: 128 PYP-2-3 14.00% V.sub.0 [20? C., V]: 2.06 PYP-2-4 13.00%

Example M19

[0496]

TABLE-US-00021 COY-3-O2 17.00% Clearing point [? C.]: 74.0 CCOY-3-O2 4.00% ?n [589 nm, 20? C.]: 0.1280 CPY-2-O2 10.00% ?? [1 kHz, 20? C.]: ?3.2 CPY-3-O2 12.00% K.sub.1 [pN, 20? C.]: 13.3 CCH-34 10.00% K.sub.3 [pN, 20? C.]: 13.1 CCH-23 20.00% ?.sub.1 [mPa .Math. s, 20? C.]: 127 PYP-2-3 14.00% V.sub.0 [20? C., V]: 2.10 PYP-2-4 13.00%

Example M20

[0497] For the preparation of a PS-VA mixture, 0.3% of RM10

##STR00340##

[0498] is added to the liquid-crystal mixture in accordance with Example M19.

[0499] The PS-VA mixture is introduced into a cell having homeotropic alignment. After application of a voltage of 24 V, the cell is irradiated with UV light with a power of 100 mW/cm.sup.2. The tilt angles have then become established:

Example M21

[0500]

TABLE-US-00022 CY-3-O2 10.00% Clearing point [? C.]: 74.5 COY-3-O2 7.00% ?n [589 nm, 20? C.]: 0.1069 CCY-3-O2 11.00% ?? [1 kHz, 20? C.]: ?3.1 CPY-2-O2 9.00% K.sub.1 [pN, 20? C.]: 13.6 CPY-3-O2 10.00% K.sub.3 [pN, 20? C.]: 14.3 CCH-23 24.00% ?.sub.1 [mPa .Math. s, 20? C.]: 105 CCH-34 5.00% V.sub.0 [20? C., V]: 2.26 PYP-2-3 7.00% PYP-2-4 7.00% CC-3-V1 8.00% PCH-301 2.00%

Example M22

[0501]

TABLE-US-00023 COY-3-O2 16.00% Clearing point [? C.]: 74.5 CCY-3-O2 11.00% ?n [589 nm, 20? C.]: 0.1068 CPY-2-O2 8.00% ?? [1 kHz, 20? C.]: ?3.0 CPY-3-O2 10.00% K.sub.1 [pN, 20? C.]: 13.8 CCH-23 24.00% K.sub.3 [pN, 20? C.]: 14.5 CCH-34 6.00% ?.sub.1 [mPa .Math. s, 20? C.]: 105 PYP-2-3 10.00% V.sub.0 [20? C., V]: 2.29 PYP-2-4 5.00% CC-3-V1 8.00% PCH-301 2.00%

[0502] Example M23

TABLE-US-00024 COY-3-O2 15.00% Clearing point [? C.]: 74.5 CCOY-3-O2 5.00% ?n [589 nm, 20? C.]: 0.1069 CCY-3-O2 6.00% ?? [1 kHz, 20? C.]: ?3.0 CPY-2-O2 8.00% K.sub.1 [pN, 20? C.]: 14.0 CPY-3-O2 10.00% K.sub.3 [pN, 20? C.]: 14.7 CCH-23 24.00% ?.sub.1 [mPa .Math. s, 20? C.]: 104 CCH-34 5.00% V.sub.0 [20? C., V]: 2.34 PYP-2-3 10.00% PYP-2-4 5.00% CC-3-V1 10.00% PCH-301 2.00%

[0503] Example M24

TABLE-US-00025 COY-3-O2 19.00% Clearing point [? C.]: 70.0 CPY-2-O2 9.00% ?n [589 nm, 20? C.]: 0.1186 CPY-3-O2 11.00% ?? [1 kHz, 20? C.]: ?3.1 CLY-3-O2 5.00% K.sub.1 [pN, 20? C.]: 12.1 PYP-2-3 11.00% K.sub.3 [pN, 20? C.]: 13.5 PYP-2-4 5.50% ?.sub.1 [mPa .Math. s, 20? C.]: 115 CCH-35 6.00% V.sub.0 [20? C., V]: 2.17 CCH-23 19.00% PCH-301 11.50% CPGP-4-3 3.00%

[0504] Example M25

TABLE-US-00026 COY-3-O2 24.00% Clearing point [? C.]: 70.0 CPY-2-O2 11.00% ?n [589 nm, 20? C.]: 0.1183 CPY-3-O2 11.00% ?? [1 kHz, 20? C.]: ?3.0 CLY-3-O2 3.00% K.sub.1 [pN, 20? C.]: 13.0 PGP-2-3 5.00% K.sub.3 [pN, 20? C.]: 14.1 PGP-2-4 6.00% ?.sub.1 [mPa .Math. s, 20? C.]: 114 PGP-2-5 6.00% V.sub.0 [20? C., V]: 2.17 CCH-35 6.00% CCH-23 19.00% PCH-301 6.50% CPGP-4-3 2.50%

[0505] Example M26

TABLE-US-00027 CCH-23 15.50% Clearing point [? C.]: 74.5 PCH-301 7.00% ?n [589 nm, 20? C.]: 0.1416 PGP-2-3 4.00% ?? [1 kHz, 20? C.]: ?2.9 PGP-2-4 7.00% K.sub.1 [pN, 20? C.]: 12.4 PGP-2-5 7.00% K.sub.3 [pN, 20? C.]: 14.1 COY-3-O2 10.50% ?.sub.1 [mPa .Math. s, 20? C.]: 147 CY-3-O2 10.00% V.sub.0 [20? C., V]: 2.24 CCY-3-O2 9.00% CPY-2-O2 7.00% CPY-3-O2 8.00% PYP-2-3 7.00% PYP-2-4 8.00%