LIQUID CRYSTAL MEDIUM

Abstract

The present invention relates to a liquid crystal (LC) medium comprising a compound of formula I

##STR00001## and one or more compounds selected from the group of compounds of the formulae IIA, IIB, IIC and IID,

##STR00002## as defined in claim 1, and to the use of the LC medium for optical, electro-optical and electronic purposes, in particular in LC displays, especially in IPS, FFS, VA or PS-VA displays.

Claims

1. A liquid crystal medium comprising one or more compounds of formula I ##STR00544## in which R.sup.L denotes H, a straight chain or branched alkyl or alkoxy radical having 1 to 15 C atoms, where one or more CH.sub.2 groups in these radicals may each be replaced, independently of one another, by ##STR00545##  —C≡C—, —CF.sub.2O—, —OCF.sub.2—, —CH═CH—, —O—, —CO—O— or —O—CO— in such a way that O atoms are not linked directly to one another, and in which, in addition, one or more H atoms may each be replaced by halogen, X.sup.L denotes F, Cl, CN, CHF.sub.2, CF.sub.3, OCF.sub.3, or, identically or differently, has one of the meanings of R.sup.L, Y.sup.L denotes H, F, Cl or CH.sub.3, and one or more compounds selected from the group of compounds of the formulae IIA, IIB, IIC and IID, ##STR00546## in which R.sup.2A, R.sup.2B, R.sup.2C and R.sup.2D each, independently of one another, denote H, an alkyl or alkenyl 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 each be replaced by —O—, —S—, ##STR00547##  —C≡C—, —CF.sub.2O—, —OCF.sub.2—, —OC—O— or —O—CO— in such a way that O atoms are not linked directly to one another, L.sup.1 to L.sup.4 each, independently of one another, denote F, Cl, CF.sub.3 or CHF.sub.2, Y denotes H, F, Cl, CF.sub.3, CHF.sub.2 or CH.sub.3, Z.sup.2, Z.sup.2B and Z.sup.2D each, independently of one another, denote 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—, —CF═CF— or —CH═CHCH.sub.2O—, p denotes 0, 1 or 2, q denotes 0 or 1, and v denotes 1, 2, 3, 4, 5, or 6, wherein the mixtures X-1 and X-2 having the following compositions TABLE-US-00077 Mixture X-1: CC-3-V1  8.0% CC-4-V1  20.0% CCH-301  10.5% CCH-303  2.0% CC-3-4  0.5% CCY-3-O2  11.0% COB(S)-2-O4  7.5% CLP-3-T  1.0% CPY-3-O2  10.5% CY-3-O2  15.5% CY-3-O4  3.5% PP-1-2V1  10.0% □ 100.0% TABLE-US-00078 Mixture X-2 B(S)-2O-O4  2.0% B(S)-2O-O5  4.0% CC-3-V  37.0% CC-3-V1  3.0% CCP-V-1  14.5% CCY-3-O2  11.5% CCY-5-O2  3.0% COB(S)-2-O4  10.0% CY-3-O2  14.0% CLP-3-T  1.0% □ 100.0% are excluded.

2. The medium according to claim 1, wherein the medium comprises one or more compounds of formula III ##STR00548## in which R.sup.11 and R.sup.12 each, independently of one another, denote H, an alkyl or alkoxy radical having 1 to 15 C atoms, where one or more CH.sub.2 groups in these radicals may each be replaced, independently of one another, by ##STR00549##  —C≡C—, —CF.sub.2O—, —OCF.sub.2—, —CH═CH—, by —O—, —CO—O— or —O—CO— in such a way that O atoms are not linked directly to one another, and in which, in addition, one or more H atoms may each be replaced by halogen, A.sup.1 on each occurrence independently denotes a) a 1,4-cyclohexenylene or 1,4-cyclohexylene radical, in which one or two non-adjacent CH.sub.2 groups may each be replaced by —O— or —S—, b) a 1,4-phenylene radical, in which one or two CH groups may each be replaced by N, or c) a radical from the group spiro[3.3]heptane-2,6-diyl, 1,4-bicyclo-[2.2.2]octylene, naphthalene-2,6-diyl, decahydronaphthalene-2,6-diyl, 1,2,3,4-tetrahydronaphthalene-2,6-diyl, phenanthrene-2,7-diyl and fluorene-2,7-diyl, where the radicals a), b) and c) may be mono- or polysubstituted by halogen atoms, n is 0, 1 or 2, Z.sup.1 on each occurrence independently denotes —CO—O—, —O—CO—, —CF.sub.2O—, —OCF.sub.2—, —CH.sub.2O—, —OCH.sub.2—, —CH.sub.2—, —CH.sub.2CH.sub.2—, —(CH.sub.2).sub.4—, —CH═CH—CH.sub.2O—, —C.sub.2F.sub.4—, —CH.sub.2CF.sub.2—, —CF.sub.2CH.sub.2—, —CF═CF—, —CH═CF—, —CF═CH—, —CH═CH—, —C≡C— or a single bond, and L.sup.11 and L.sup.12 each, independently of one another, denote H, F, Cl, CF.sub.3 or CHF.sub.2, and W denotes O or S.

3. The medium according to claim 1, wherein the medium comprises one or more compounds of formula IV ##STR00550## in which R.sup.41 denotes alkyl having 1 to 7 C atoms or alkenyl having 2 to 7 C atoms, and R.sup.42 denotes alkyl having 1 to 7 C atoms or alkoxy having 1 to 6 C atoms or alkenyl having 2 to 7 C atoms.

4. The medium according to claim 1, wherein the medium comprises one or more compounds selected from the group of compounds of the following formulae: ##STR00551##

5. The medium according to claim 1, wherein the medium comprises one or more compounds of formula IVb-1 to IVb-3 ##STR00552## in which alkyl and alkyl* each, independently of one another, denote alkyl having 1 to 6 C atoms, and alkenyl and alkenyl* each, independently of one another, denote alkenyl having 2 to 6 C atoms.

6. The medium according to claim 1, wherein the medium comprises one or more compounds of formula V ##STR00553## in which R.sup.51, R.sup.52 denote alkyl having 1 to 7 C atoms, alkoxy having 1 to 7 C atoms, or alkoxyalkyl, alkenyl or alkenyloxy having 2 to 7 C atoms, ##STR00554##  identically or differently, denote ##STR00555## Z.sup.51, Z.sup.52 each, independently of one another, denote —CH.sub.2—CH.sub.2—, —CH.sub.2—O—, —CH═CH—, —C≡C—, —COO— or a single bond, and n is 1 or 2.

7. The medium according to claim 1, wherein the medium comprises a chiral dopant.

8. The medium according to claim 1, wherein the medium comprises one or more polymerizable compounds of formula P
P-Sp-A.sup.1-(Z.sup.1-A.sup.2).sub.z-R  P in which P denotes a polymerizable group, Sp denotes a spacer group or a single bond, A.sup.1, A.sup.2 identically or differently, denote an aromatic, heteroaromatic, alicyclic or heterocyclic group, which may also contain fused rings, and which is unsubstituted, or mono- or polysubstituted by L, L denotes F, Cl, —CN, P-Sp- or straight chain, branched or cyclic alkyl having 1 to 25 C atoms, wherein one or more non-adjacent CH.sub.2-groups are each optionally replaced by —O—, —S—, —CO—, —CO—O—, —O—CO—, or —O—CO—O— in such a manner that O- and/or S-atoms are not directly connected with each other, and wherein one or more H atoms are each optionally replaced by P-Sp-, F or Cl, Z.sup.1 denotes —O—, —S—, —CO—, —CO—O—, —O—CO—, —O—CO—O—, —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)n.sub.1-, —CF.sub.2CH.sub.2—, —CH.sub.2CF.sub.2—, —(CF.sub.2).sub.n1—, —CH═CH—, —CF═CF—, —CH═CF—, —CF═CH—, —C≡C—, —CH═CH—CO—O—, —O—CO—CH═CH—, —CH.sub.2—CH.sub.2—CO—O—, —O—CO—CH.sub.2—CH.sub.2—, —CR.sup.0R.sup.00—, or a single bond, R.sup.0, R.sup.00 identically or differently, denote H or alkyl having 1 to 12 C atoms, R denotes H, L, or P-Sp-, z is 0, 1, 2 or 3, n1 is 1, 2, 3 or 4.

9. LC medium according to claim 8, wherein the polymerizable compounds of formula P are polymerized.

10. A process of preparing a liquid crystal medium according to claim 1, comprising mixing one or more compounds selected from the group consisting of the formulae I, IIA, IIB, IIC, IID of claim 1 with one or more mesogenic or liquid-crystalline compounds and optionally with a polymerizable compound, and optionally with one or more additives.

11. LC display comprising a medium according to claim 1.

12. LC display according to claim 11, wherein the display is a PSA display.

13. LC display according to claim 12, wherein the display is a PS-VA, PS-IPS, PS-FFS, PS-UB-FFS, polymer stabilized SA-VA or polymer stabilized SA-FFS display.

14. LC display according to claim 11, wherein the display is a VA, IPS, U-IPS, FFS, UB-FFS, SA-FFS or SA-VA display.

15. Use of the liquid-crystalline medium according to claim 1 in electro-optical displays.

Description

WORKING EXAMPLES

[0448] The following examples are intended to explain the invention without limiting it. In the examples, m.p. denotes the melting point and T.sub.(N,I) denotes the clearing point of a liquid-crystalline substance in degrees Celsius; Furthermore: 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, and T.sub.g denotes glass-transition temperature. The number between two symbols indicates the conversion temperature in degrees Celsius.

[0449] The host mixture used for determination of the optical anisotropy Δn of single compounds is the commercial mixture ZLI-4792 (Merck KGaA). The dielectric anisotropy Δε 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.

[0450] Unless indicated otherwise, parts or percent data denote parts by weight or percent by weight.

[0451] Above and Below: [0452] V.sub.o denotes threshold voltage, capacitive [V] at 20° C., [0453] n.sub.e denotes extraordinary refractive index at 20° C. and 589 nm, [0454] n.sub.o denotes ordinary refractive index at 20° C. and 589 nm, [0455] Δn denotes optical anisotropy at 20° C. and 589 nm, [0456] ε.sub.⊥ denotes dielectric permittivity perpendicular to the director at 20° C. and 1 kHz, [0457] ε.sub.∥ denotes dielectric permittivity parallel to the director at 20° C. and 1 kHz, [0458] Δε denotes dielectric anisotropy at 20° C. and 1 kHz, [0459] cl.p., T(N,I) denotes clearing point [° C.], [0460] γ.sub.1 denotes rotational viscosity measured at 20° C. [mPa.Math.s], [0461] K.sub.1 denotes elastic constant, “splay” deformation at 20° C. [pN], [0462] K.sub.2 denotes elastic constant, “twist” deformation at 20° C. [pN], [0463] K.sub.3 denotes elastic constant, “bend” deformation at 20° C. [pN], and [0464] LTS denotes low-temperature stability (nematic phase), determined in test cells or in the bulk, as specified.

[0465] Unless explicitly noted otherwise, all values indicated in the present application for temperatures, such as, for example, the melting point T(C,N), the transition from the smectic (S) to the nematic (N) phase T(S,N) and the clearing point T(N,I) or cl.p., are indicated in degrees Celsius (° C.).

[0466] The term “threshold voltage” for the present invention relates to the capacitive threshold (V.sub.0), also called the Freedericksz threshold, unless explicitly indicated otherwise. In the examples, as is generally usual, the optical threshold can also be indicated for 10% relative contrast (V.sub.10).

[0467] The display used for measurement of the capacitive threshold voltage consists of two plane-parallel glass outer plates at a separation of 20 μm, which each have on the insides an electrode layer and an unrubbed polyimide alignment layer on top, which cause a homeotropic edge alignment of the liquid-crystal molecules.

[0468] The display or test cell used for measurement of the tilt angle consists of two plane-parallel glass outer plates at a separation of 4 μm, which each have on the insides an electrode layer and a polyimide alignment layer on top, where the two polyimide layers are rubbed antiparallel to one another and cause a homeotropic edge alignment of the liquid-crystal molecules.

[0469] The polymerizable compounds are polymerized in the display or test cell by irradiation with UV light of defined intensity for a prespecified 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 is used for polymerization. The intensity is measured using a standard meter (Hoenle UV-meter high end with UV sensor).

[0470] The tilt angle is determined using the Mueller Matrix Polarimeter “AxoScan” from Axometrics. A low value (i.e. a large deviation from the 90° angle) corresponds to a large tilt here.

[0471] Unless stated otherwise, the term “tilt angle” means the angle between the LC director and the substrate, and “LC director” means in a layer of LC molecules with uniform orientation the preferred orientation direction of the optical main axis of the LC molecules, which corresponds, in case of calamitic, uniaxially positive birefringent LC molecules, to their molecular long axis.

[0472] Unless indicated otherwise, the VHR is determined at 20° C. (VHR.sub.20) and after 5 minutes in an oven at 100° C. (VHR.sub.100) in a commercially available instrument Model LCM-1 (00004) from TOYO Corporation, Japan. The voltage used has a frequency of in a range from 1 Hz to 60 Hz, unless indicated more precisely.

[0473] The accuracy of the VHR measurement values depends on the respective value of the VHR. The accuracy decreases with decreasing values. The deviations generally observed in the case of values in the various magnitude ranges are compiled in their order of magnitude in the following table.

TABLE-US-00011 VHR range Deviation (relative) VHR values Δ.sub.GVHR/VHR/% from to Approx. 99.6%  100% +/−0.1 99.0% 99.6% +/−0.2   98%   99% +/−0.3   95%   98% +/−0.5   90%   95% +/−1     80%   90% +/−2     60%   80% +/−4     40%   60% +/−8     20%   40% +/−10     10%   20% +/−20  

[0474] The stability to UV irradiation is investigated in a “Suntest CPS+”, a commercial instrument from Heraeus, Germany, using a Xenon lamp NXE1500B. The sealed test cells are irradiated for 2.0 h, unless explicitly indicated, without additional heating. The irradiation power in the wavelength range from 300 nm to 800 nm is 765 W/m.sup.2 V. A UV “cut-off” filter having an edge wavelength of 310 nm is used in order to simulate the so-called window glass mode. In each series of experiments, at least four test cells are investigated for each condition, and the respective results are indicated as averages of the corresponding individual measurements.

[0475] The decrease in the voltage holding ratio (ΔVHR) usually caused by the exposure, for example by UV irradiation or by LCD backlighting, is determined in accordance with the following equation (1):

ΔVHR(t)=VHR(t)−VHR(t=0)  (1)

[0476] In order to investigate the low-temperature stability, also known as “LTS”, i.e. the stability of the LC mixture in the bulk against spontaneous crystallization of individual components at low temperatures or the occurrence of smectic phases, as the case may be, several sealed bottles, each containing about 1 g of the material, are stored at one or more given temperatures, typically of −10° C., −20° C., −30° C. and/or −40° C. and it is inspected at regular intervals visually, whether a phase transition is observed or not. As soon as the first one of the samples at a given temperature shows a change time is noted. The time until the last inspection, at which no change has been observed, is noted as the respective LTS.

[0477] The ion density from which the resistivity is calculated is measured using the commercially available LC Material Characteristics Measurement System Model 6254 from Toyo Corporation, Japan, using VHR test cells with AL16301 Polyimide (JSR Corp., Japan) having a 3.2 μm cell gap. The measurement is performed after 5 min of storage in an oven at 60° C. or 100° C.

[0478] The so-called “HTP” denotes the helical twisting power of an optically active or chiral substance in an LC medium (in μm). Unless indicated otherwise, the HTP is measured in the commercially available nematic LC host mixture MLD-6260 (Merck KGaA) at a temperature of 20° C.

[0479] The Clearing point is measured using the Mettler Thermosystem FP900. The optical anisotropy (Δn) is measured using an Abbe-Refraktometer H005 (Natrium-spectral lamp Na10 at 589 nm, 20° C.). The dielectric anisotropy (Δε) is measured using an LCR-Meter E4980A/Agilent (G005) at 20° C. (c-parallel-cells with JALS 2096-R1). The turn on voltage (V.sub.0) is measured using an LCR-Meter E4980A/Agilent (G005) at 20° C. (ε-parallel-cells with JALS 2096-R1). The rotational viscosity (γ.sub.1) is measured using a TOYO LCM-2 (0002) at 20° C. (gamma 1 negative cells with JALS-2096-R 1). The elastic constant (K.sub.1, splay) is measured using an LCR-Meter E4980A/Agilent (G005) at 20° C. (ε parallel-cells with JALS 2096-R1). K.sub.3: The elastic constant (K.sub.3, bend) is measured using an LCR-Meter E4980A/Agilent (G005) at 20° C. (ε-parallel-cells with JALS 2096-R1).

[0480] Unless explicitly noted otherwise, all concentrations in the present application are indicated in percent by weight and relate to the corresponding mixture as a whole, comprising all solid or liquid-crystalline components, without solvents. All physical properties are determined in accordance with “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.

[0481] The following mixture examples having negative dielectric anisotropy are suitable, in particular, for liquid-crystal displays which have at least one planar alignment layer, such as, for example, IPS and FFS displays, in particular UB-FFS(=ultra-bright FFS), and for VA displays.

MIXTURE EXAMPLES AND COMPARATIVE EXAMPLES

[0482] Comparative Mixtures C1 to C4 and Mixture Examples M1 to M95 are prepared and investigated as given in the following tables.

TABLE-US-00012 Comparative Mixture C1 B(S)—2O—O4 3.5% Clearing point/° C.: 74.0 B(S)—2O—O5 4.0% Δn (589 nm, 20° C.): 0.1031 CPP-3-2 1.5% Δε (1 kHz, 20° C.): −3.0 CC-3-V1 7.0% K.sub.1 (pN, 20° C.): 15.5 CC-4-V1 16.5% K.sub.3 (pN, 20° C.): 15.6 CC-3-O1 11.5% V.sub.0 (20° C.)/V: 2.40 CC-3-O3 2.0% γ.sub.1 (20° C.)/mPa .Math. s: 96 CC-3-4 4.5% VHR initial [%]: 99.2 CC-3-5 5.0% VHR after 2 h suntest [%]: 86.0 CCY-3-O2 7.0% CPY-2-O2 5.5% CPY-3-O2 11.5% CY-3-O2 13.5% PP-1-2V1 7.0% Σ 100.0%

TABLE-US-00013 Comparative Mixture C2 B(S)—2O—O4 4.0% Clearing point/° C.: 74.2 B(S)—2O—O5 5.0% Δn (589 nm, 20° C.): 0.1270 B(S)—2O—O6 3.0% Δε (1 kHz, 20° C.): −2.7 CPP-3-2 11.0% K.sub.1 (pN, 20° C.): 14.5 CC-3-V 26.0% K.sub.3 (pN, 20° C.): 15.1 CC-3-V1 8.0% V.sub.0 (20° C.)/V: 2.48 CCP-3-1 11.0% γ.sub.1 (20° C.)/mPa .Math. s: 80 CPY-2-O2 11.0% PP-1-2V1 5.0% PY-1-O2 12.0% PY-2-O2 4.0% Σ 100.0%

TABLE-US-00014 Comparative Mixture C3 B(S)—2O—O4 5.0% Clearing point/° C.: 73.4 B(S)—2O—O5 5.0% Δn (589 nm, 20° C.): 0.1257 B(S)—2O—O6 4.0% Δε (1 kHz, 20° C.): −2.7 CPP-3-2 5.5% K.sub.1 (pN, 20° C.): 13.9 CC-3-V 32.5% K.sub.3 (pN, 20° C.): 14.1 CC-3-V1 2.5% V.sub.0 (20° C.)/V: 2.40 CCP-V-1 16.5% γ.sub.1 (20° C.)/mPa .Math. s: 75 COB(S)-2-O4 1.5% CPY-2-O2 6.0% PP-1-2V1 3.5% PY-1-O2 12.5% PYP-2-3 5.5% Σ 100.0%

TABLE-US-00015 Comparative Mixture C4 B(S)—2O—O4 4.0% Clearing point/° C.: 74.1 B(S)—2O—O5 5.0% Δn (589 nm, 20° C.): 0.1164 B(S)—2O—O6 3.0% Δε (1 kHz, 20° C.): −2.7 CPP-3-2 11.0% K.sub.1 (pN, 20° C.): 14.1 CC-3-V 31.0% K.sub.3 (pN, 20° C.): 14.7 CC-3-V1 8.0% V.sub.0 (20° C.)/V: 2.47 CCP-3-1 12.0% γ.sub.1 (20° C.)/mPa .Math. s: 72 CLY-3-O2 3.0% CPY-2-O2 5.0% PY-1-O2 11.0% PY-2-O2 7.0% Σ 100.0%

TABLE-US-00016 Mixture Example M1 B(S)—2O—O4 3.0% Clearing point/° C.: 79.0 B(S)—2O—O5 5.0% Δn (589 nm, 20° C.): 0.1028 CC-3-V1 8.0% Δε (1 kHz, 20° C.): −3.2 CC-4-V1 14.0% K.sub.1 (pN, 20° C.): 16.9 CC-3-O1 7.0% K.sub.3 (pN, 20° C.): 16.2 CC-3-4 3.0% V.sub.0 (20° C.)/V: 2.39 CC-3-5 5.0% γ.sub.1 (20° C.)/mPa .Math. s: 125 CCY-3-O2 7.5% VHR initial [%]: 99.3 CLP-3-T 9.0% VHR after 2 h suntest [%]: 95.2 CPY-2-O2 4.5% CPY-3-O2 11.5% CY-3-O2 15.0% CY-3-O4 5.5% PY-1-O2 2.0% Σ 100.0%

TABLE-US-00017 Mixture M2 B(S)—2O—O4 3.5% Clearing point/° C.: 75.5 B(S)—2O—O5 4.0% Δn (589 nm, 20° C.): 0.1036 CC-3-V1 8.0% Δε (1 kHz, 20° C.): −2.8 CC-4-V1 16.5% K.sub.1 (pN, 20° C.): 16.0 CC-3-O1 11.5% K.sub.3 (pN, 20° C.): 15.8 CC-3-O3 2.0% V.sub.0 (20° C.)/V: 2.49 CC-3-4 4.5% γ.sub.1 (20° C.)/mPa .Math. s: 96 CC-3-5 5.0% VHR initial [%]: 99.4 CCY-3-O2 6.5% VHR after 2 h suntest [%]: 96.2 CLP-3-T 1.0% CPY-2-O2 7.5% CPY-3-O2 11.0% CY-3-O2 11.5% PP-1-2V1 7.5% Σ 100.0%

TABLE-US-00018 Mixture M3 B(S)—2O—O4  5.0% Clearing point/° C.: 75.0 B(S)—2O—O5  4.0% Δn (589 nm, 20° C.): 0.1038 CC-3-V1  8.0% Δϵ (1 kHz, 20° C.): −3.2 CC-4-V1  20.0% K.sub.1 (pN, 20° C.): 17.0 CC-3-O3  11.0% K.sub.3 (pN, 20° C.): 16.9 CC-3-4  5.0% V.sub.0 (20° C.)/V: 2.43 CCY-3-O2  11.5% γ.sub.1 (20° C.)/mPa .Math. s: 99 CLP-3-T  1.0% VHR initial [%]: 99.3 CPY-3-O2  10.0% VHR after 2 h suntest [%]: 93.8 CY-3-O2  15.0% CY-3-O4  1.0% PP-1-2V1  8.5% Σ 100.0%

TABLE-US-00019 Mixture M4 B(S)—2O—O4  3.5% Clearing point/° C.: 75.0 B(S)—2O—O5  4.0% Δn (589 nm, 20° C.): 0.1024 CPP-3-2  2.5% Δϵ (1 kHz, 20° C.): −3.0 CC-3-V1  7.0% K.sub.1 (pN, 20° C.): 15.2 CC-4-V1  16.5% K.sub.3 (pN, 20° C.): 15.3 CC-3-O1  11.5% V.sub.0 (20° C.)/V: 2.40 CC-3-O3  2.0% γ.sub.1 (20° C.)/mPa .Math. s: 97 CC-3-4  4.5% VHR initial [%]: 99.3 CC-3-5  5.0% VHR after 2 h suntest [%]: 95.5 CCY-3-O2  5.0% CLP-3-F  1.0% CPY-2-O2  6.5% CPY-3-O2  11.5% CY-3-O2  14.0% PP-1-2V1  5.5% Σ 100.0%

TABLE-US-00020 Mixture M5 B(S)—2O—O4  5.0% Clearing point/° C.: 75.0 B(S)—2O—O5  4.0% Δn (589 nm, 20° C.): 0.1022 CC-3-V1  8.0% Δϵ (1 kHz, 20° C.): −2.9 CC-4-V1  17.0% K.sub.1 (pN, 20° C.): 16.5 CC-3-O1  7.5% K.sub.3 (pN, 20° C.): 16.2 CC-3-4  4.5% V.sub.0 (20° C.)/V: 2.48 CC-3-5  5.0% γ.sub.1 (20° C.)/mPa .Math. s: 98 CCY-3-O2  7.5% VHR initial [%]: 99.3 CLP-3-F  9.0% VHR after 2 h suntest [%]: 95.2 CPY-3-O2  9.0% CY-3-O2  12.0% CY-3-O4  3.0% PY-1-O2  5.0% PP-1-2V1  3.5% Σ 100.0%

[0483] The comparison of example mixtures M1 to M5 with medium C1 shows significantly improved VHR of the liquid crystalline media according to the invention.

TABLE-US-00021 Mixture M6 B(S)—2O—O4  5.0% Clearing point/° C.: 71.0 B(S)—2O—O5  4.0% Δn (589 nm, 20° C.): 0.1022 CC-3-V1  8.0% Δϵ (1 kHz, 20° C.): −2.5 CC-4-V1  17.0% K.sub.1 (pN, 20° C.): 17.0 CC-3-O1  7.5% K.sub.3 (pN, 20° C.): 16.9 CC-3-4  5.5% V.sub.0 (20° C.)/V: 2.64 CC-3-5  6.0% γ.sub.1 (20° C.)/mPa .Math. s: 88 CCY-3-O2  5.5% CLP-3-F  9.0% CPY-3-O2  7.0% CY-3-O2  12.0% CY-3-O4  2.0% PY-1-O2  5.0% PP-1-2V1  6.5% Σ 100.0%

TABLE-US-00022 Mixture M7 B(S)—2O—O4  4.0% Clearing point/° C.: 74.0 B(S)—2O—O5  3.0% Δn (589 nm, 20° C.): 0.1369 B(S)—2O—O6  3.0% Δϵ (1 kHz, 20° C.): −3.0 CC-3-V  24.5% K.sub.1 (pN, 20° C.): 15.4 CC-3-V1  8.0% K.sub.3 (pN, 20° C.): 16.0 CCP-3-1  12.0% V.sub.0 (20° C.)/V: 2.43 CPY-3-O2  11.0% γ.sub.1 (20° C.)/mPa .Math. s: 93 PP-1-2V1  3.0% PY-1-O2  12.0% PY-3-O2  5.5% PYP-2-3  10.0% PYP-2-4  3.0% CLP-3-T  1.0% Σ 100.0%

TABLE-US-00023 Mixture M8 B(S)—2O—O4  4.0% Clearing point/° C.: 74.7 B(S)—2O—O5  5.0% Δn (589 nm, 20° C.): 0.1274 B(S)—2O—O6  3.0% Δϵ (1 kHz, 20° C.): −2.7 CPP-3-2  11.0% K.sub.1 (pN, 20° C.): 14.8 CC-3-V  25.5% K.sub.3 (pN, 20° C.): 15.1 CC-3-V1  8.0% V.sub.0 (20° C.)/V: 80 CCP-3-1  10.5% γ.sub.1 (20° C.)/mPa .Math. s: 2.49 CPY-2-O2  11.0% PP-1-2V1  4.5% PY-1-O2  12.0% PY-2-O2  4.5% CLP-3-T  1.0% Σ 100.0%

TABLE-US-00024 Mixture M9 B(S)—2O—O4  4.0% Clearing point/° C.: 74.8 B(S)—2O—O5  5.0% Δn (589 nm, 20° C.): 0.1376 B(S)—2O—O6  3.0% Δϵ (1 kHz, 20° C.): −2.7 CPP-3-2  11.5% V.sub.0 (20° C.)/V: 2.45 CC-3-V  28.5% K.sub.1 (pN, 20° C.): 14.6 CCP-3-1  9.5% K.sub.3 (pN, 20° C.): 14.7 CPY-2-O2  11.0% γ.sub.1 (20° C.)/mPa .Math. s: 86 PP-1-2V1  7.0% PY-1-O2  12.0% PY-2-O2  2.5% PYP-2-3  5.0% CLP-3-T  1.0% Σ 100.0%

TABLE-US-00025 Mixture M10 B(S)—2O—O4  4.0% Clearing point/° C.: 74.4 B(S)—2O—O5  5.0% Δn (589 nm, 20° C.): 0.1274 B(S)—2O—O6  3.0% Δϵ (1 kHz, 20° C.): −2.7 CPP-3-2  11.0% K.sub.1 (pN, 20° C.): 14.8 CC-3-V  25.5% K.sub.3 (pN, 20° C.): 15.1 CC-3-V1  8.0% V.sub.0 (20° C.)/V: 2.49 CCP-3-1  10.5% γ.sub.1 (20° C.)/mPa .Math. s: 80 CLP-3-T  1.0% CPY-2-O2  11.0% PP-1-2V1  4.5% PY-1-O2  12.0% PY-2-O2  4.5% Σ 100.0%

TABLE-US-00026 Mixture M11 B(S)—2O—O4  4.0% Clearing point/° C.: 74.3 B(S)—2O—O5  5.0% Δn (589 nm, 20° C.): 0.1373 B(S)—2O—O6  3.0% Δϵ (1 kHz, 20° C.): −2.7 CPP-3-2  11.0% K.sub.1 (pN, 20° C.): 14.4 CC-3-V  23.5% K.sub.3 (pN, 20° C.): 14.6 CC-3-V1  6.5% V.sub.0 (20° C.)/V: 2.44 CCP—V-1  9.0% γ.sub.1 (20° C.)/mPa .Math. s: 84 CLP-3-T  1.0% CPY-2-O2  11.0% PP-1-2V1  6.5% PY-1-O2  12.0% PY-2-O2  2.5% PYP-2-3  5.0% Σ 100.0%

TABLE-US-00027 Mixture M12 B(S)—2O—O4  4.0% Clearing point/° C.: 74.1 B(S)—2O—O5  5.0% Δn (589 nm, 20° C.): 0.1371 B(S)—2O—O6  2.5% Δϵ (1 kHz, 20° C.): −2.7 CPP-3-2  11.0% K.sub.1 (pN, 20° C.): 14.9 CC-3-V  22.0% K.sub.3 (pN, 20° C.): 14.8 CC-3-V1  9.0% V.sub.0 (20° C.)/V: 2.45 CCP-3-1  5.5% γ.sub.1 (20° C.)/mPa .Math. s: 87 CLP-3-T  3.0% CPY-2-O2  11.0% PP-1-2V1  5.0% PY-1-O2  12.0% PY-2-O2  4.5% PYP-2-3  5.0% Σ 100.0%

TABLE-US-00028 Mixture M13 B(S)—2O—O4  4.0% Clearing point/° C.: 74.3 B(S)—2O—O5  5.0% Δn (589 nm, 20° C.): 0.1378 B(S)—2O—O6  3.0% Δϵ (1 kHz, 20° C.): −2.6 CPP-3-2  11.5% K.sub.1 (pN, 20° C.): 15.1 CC-3-V  21.5% K.sub.3 (pN, 20° C.): 14.4 CC-3-V1  8.5% V.sub.0 (20° C.)/V: 2.44 CCP-3-1  4.0% γ.sub.1 (20° C.)/mPa .Math. s: 91 CLP-3-T  5.0% CPY-2-O2  11.0% PP-1-2V1  3.5% PY-1-O2  12.0% PY-2-O2  6.0% PYP-2-3  5.0% Σ 100.0%

TABLE-US-00029 MIXTURE M14 B(S)—2O—O4  5.0% Clearing point/° C.: 74.1 B(S)—2O—O5  5.0% Δn (589 nm, 20° C.): 0.1261 B(S)—2O—O6  4.0% Δϵ (1 kHz, 20° C.): −2.7 CPP-3-2  5.5% K.sub.1 (pN, 20° C.): 13.8 CC-3-V  32.0% K.sub.3 (pN, 20° C.): 14.2 CC-3-V1  2.5% V.sub.0 (20° C.)/V: 2.42 CCP—V-1  16.5% γ.sub.1 (20° C.)/mPa .Math. s: 74 CLP-3-T  0.5% COB(S)-2-O4  1.5% CPY-2-O2  6.0% PP-1-2V1  3.5% PY-1-O2  12.5% PYP-2-3  5.5% Σ 100.0%

TABLE-US-00030 Mixture M15 B(S)—2O—O4  5.0% Clearing point/° C.: 73.2 B(S)—2O—O5  3.0% Δn (589 nm, 20° C.): 0.1257 B(S)-(c5)1O—O2  2.0% Δϵ (1 kHz, 20° C.): −2.6 B(S)-2O—O6  4.0% γ.sub.1 (20° C.)/mPa .Math. s: 83 CPP-3-2  5.5% CC-3-V  32.0% CC-3-V1  2.5% CCP—V-1  1.5% CLP-3-T  0.5% COB(S)-2-O4  1.5% CPY-2-O2  6.0% PP-1-2V1  3.5% PY-1-O2  12.5% PYP-2-3  5.5% Σ 100.0%

TABLE-US-00031 Mixture M16 B(S)—2O—O4  5.0% Clearing point/° C.: 71.2 B(S)—2O—O5  3.0% Δn (589 nm, 20° C.): 0.1250 B(S)-(c5)1O—O2  2.0% Δϵ (1 kHz, 20° C.): −2.6 B(S)-(c5)1O—O3  2.0% γ.sub.1 (20° C.)/mPa .Math. s: 87 B(S)-20-06  2.0% CPP-3-2  5.5% CC-3-V  32.0% CC-3-V1  2.5% CCP—V-1  16.5% CLP-3-T  0.5% COB(S)-2-O4  1.5% CPY-2-O2  6.0% PP-1-2V1  3.5% PY-1-O2  12.5% PYP-2-3  5.5% Σ 100.0%

TABLE-US-00032 Mixture M17 B(S)—2O—O4  4.0% Clearing point/° C.: 72.1 B(S)-(c5)1O—O2  5.0% Δn (589 nm, 20° C.): 0.1369 B(S)-2O—O6  3.0% Δϵ (1 kHz, 20° C.): −2.6 CPP-3-2  11.0% γ.sub.1 (20° C.)/mPa .Math. s: 88 CC-3-V  23.5% CC-3-V1  6.5% CCP—V-1  9.0% CLP-3-T  1.0% CPY-2-O2  11.0% PP-1-2V1  6.5% PY-1-O2  12.0% PY-2-O2  2.5% PYP-2-3  5.0% Σ 100.0%

[0484] Despite the surprising stabilizing effect of the compounds of formula I in the medium according to the invention the stability of the media can be further improved in particular against combined heat and light load by using stabilizers.

[0485] The following mixtures M18 to M54 additionally contain the stabilizers indicated above. The amount of host mixture and the amount of stabilizer given in the table add up to give 100% by weight.

TABLE-US-00033 TABLE 1 Mixtures comprising stabilizers. Host- Mixture Mixture Stabilizer (percentage in the mixture) M18 M1 0.03% of ST-3a-1 M19 M2 0.02% of ST-12 M20 M3 0.01% of ST-3b-1 M21 M4 0.03% of ST-2a-1 and 0.02% of ST-3a-1 M22 M5 0.03% of ST-2a-1 M23 M6 0.015% of ST-9-1 M24 M7 0.015% of ST-8-1 M25 M8 0.03% of ST-12 M26 M9 0.03% of ST-8-1 M27 M1 0.25% of ST-3a-1 M28 M2 0.02% of ST-8-1 and 0.01% of ST-3a-1 M29 M3 0.02% of ST-8-1 and 0.1% of ST-3a-1 M30 M4 0.01% of ST-3a-1 M31 M5 0.025% of ST-8-1 M32 M6 0.025% of ST-12 M33 M7 0.02% of ST-9-1 and 0.02% of ST-3b-1 M34 M8 0.04% of ST-3b-1 and 0.01% of ST-9-1 M35 M9 0.02% of ST-3a-1 and 0.05% of ST-3b-1 M36 M1 0.02% of ST-3a-1 and 0.01% of ST-8-1 M37 M2 0.02% of ST-3a-1 and 0.3% of the compound of the formula [00529] M38 M3 0.01% of ST-17 M39 M4 0.05% of ST-3b-1 and 0.15% of ST-12 M40 M5 0.02% of ST-8-1 M41 M6 0.02% of ST-12 M42 M7 0.01% of ST-3b-1 M43 M8 0.03% of ST-2a-1 and 0.02% of ST-3a-1 M44 M9 0.03% of ST-2a-1 M45 M1 0.015% of ST-9-1 M46 M2 0.015% of ST-8-1 M47 M3 0.03% of ST-12 M48 M4 0.03% of ST-8-1 M49 M5 0.25% of ST-3a-1 M50 M6 0.02% of ST-8-1 and 0.01% of ST-3a-1 M51 M7 0.02% of ST-8-1 and 0.1% of ST-3a-1 M52 M8 0.01% of ST-3a-1 M53 M9 0.025% of ST-8-1 M54 M9 0.01% of ST-17

[0486] The chiral nematic mixture M55 consists of 99.20% of Mixture M18 and 0.80% of chiral dopant S-2011:

##STR00530##

[0487] Mixture M55 is distinguished by very high stability under UV load and shows improved switching times.

TABLE-US-00034 Mixture M56 CC-3-V1 8.0 Clearing point [° C.]: 75.2 CC-4-V1 12.0 Δn [589 nm, 20° C.]: 0.1042 CCH-301 14.0 Δε [1 kHz, 20° C.]: −3.0 CCH-34 3.5 V.sub.0 [V, 20° C.]: 2.40 CCY-3-O2 8.0 γ.sub.1 [mPa s, 20° C.]: 119 CCY-4-O2 3.5 K.sub.1 [pN, 20° C.]: 14.6 CLP-3-T 5.5 K.sub.3 [pN, 20° C.]: 15.6 CPY-2-O2 8.0 LTS bulk [h, −20° C.]: 1000 CPY-3-O2 12.0 CY-3-O2 14.0 PP-1-2V1 1.0 PY-1-O2 9.5 PYP-2-3 1.0 Σ 100.0

TABLE-US-00035 Mixture M57 CCH-301 8.0 Clearing point [° C.]: 75.3 CCH-303 3.0 Δn [589 nm, 20° C.]: 0.1054 CCH-34 4.0 Δε [1 kHz, 20° C.]: −2.8 CCP-3-1 8.0 V.sub.0 [V, 20° C.]: 2.39 CCP-3-3 9.0 γ.sub.1 [mPa s, 20° C.]: 143 CCP-V2-1 7.0 K.sub.1 [pN, 20° C.]: 14.8 CLP-3-T 5.0 K.sub.3 [pN, 20° C.]: 14.5 CPY-2-O2 8.0 LTS bulk [h, −20° C.]: 1000 CPY-3-O2 8.5 CY-3-O4 10.0 CY-5-O2 10.0 CY-5-O4 9.0 PPGU-3-F 0.5 PY-1-O2 2.0 PY-3-O2 8.0 Σ 100.0

TABLE-US-00036 Mixture M58 B(S)-2O-O4 5.0 Clearing point [° C.]: 74.9 B(S)-2O-O5 4.0 Δn [589 nm, 20° C.]: 0.1045 CC-3-V1 8.0 Δε [1 kHz, 20° C.]: −3.0 CC-4-V1 13.0 V.sub.0 [V, 20° C.]: 2.41 CCH-301 6.0 γ.sub.1 [mPa s, 20° C.]: 112 CCH-34 5.0 K.sub.1 [pN, 20° C.]: 16.7 CCH-35 5.5 K.sub.3 [pN, 20° C.]: 15.6 CCY-3-O2 6.5 LTS bulk [h, −20° C.]: 1000 CLP-3-T 9.0 CPY-2-O2 2.5 CPY-3-O2 10.0 CY-3-O2 14.5 CY-3-O4 5.0 PP-1-2V1 2.0 PY-1-O2 4.0 Σ 100.0

TABLE-US-00037 Mixture M59 B(S)-2O-O4 4.5 Clearing point [° C.]: 72.4 B(S)-2O-O5 5.0 Δn [589 nm, 20° C.]: 0.1167 B(S)-2O-O6 3.5 Δε [1 kHz, 20° C.]: −2.6 CC-3-V 38.0 V.sub.0 [V, 20° C.]: 2.47 CCP-3-1 4.5 γ.sub.1 [mPa s, 20° C.]: 69 CCP-V-1 15.0 K.sub.1 [pN, 20° C.]: 14.2 CLP-3-T 1.0 K.sub.3 [pN, 20° C.]: 14.4 COB(S)-2-O4 10.0 PP-1-2V1 8.5 PY-1-O2 10.0 Σ 100.0

TABLE-US-00038 Mixture M60 B(S)-2O-O4 5.0 Clearing point [° C.]: 74.4 B(S)-2O-O5 5.0 Δn [589 nm, 20° C.]: 0.1382 B(S)-2O-O6 4.0 Δε [1 kHz, 20° C.]: −2.0 CPP-3-2 12.0 V.sub.0 [V, 20° C.]: 2.81 CC-3-V 29.0 K.sub.1 [pN, 20° C.]: 14.9 CCP-V-1 15.0 K.sub.3 [pN, 20° C.]: 14.4 CLP-3-T 0.5 COB(S)-2-O4 1.0 PP-1-2V1 10.5 PY-1-O2 10.0 PYP-2-3 8.0 Σ 100.0

TABLE-US-00039 Mixture M61 B(S)-2O-O4 4.5 Clearing point [° C.]: 73.9 B(S)-2O-O5 5.0 Δn [589 nm, 20° C.]: 0.1514 B(S)-2O-O6 4.0 Δε [1 kHz, 20° C.]: −2.7 CPP-3-2 12.0 V.sub.0 [V, 20° C.]: 2.47 CC-3-V 18.5 K.sub.1 [pN, 20° C.]: 14.6 CCP-V-1 16.0 K.sub.3 [pN, 20° C.]: 14.9 CLP-3-T 0.5 CPY-2-O2 4.0 PP-1-2V1 11.5 PY-1-O2 12.5 PY-2-O2 3.5 PYP-2-3 8.0 Σ 100.0

TABLE-US-00040 Mixture M62 B(S)-2O-O4 5.0 Clearing point [° C.]: 68 B(S)-2O-O5 5.0 Δn [589 nm, 20° C.]: 0.1260 B(S)-2O-O6 4.0 Δε [1 kHz, 20° C.]: −2.6 CPP-3-2 1.0 V.sub.0 [V, 20° C.]: 2.44 CC-3-V 30.0 K.sub.1 [pN, 20° C.]: 13.5 CC-3-V1 5.5 K.sub.3 [pN, 20° C.]: 14.1 CCP-V-1 16.5 CLP-3-T 0.5 COB(S)-2-O4 1.0 CPY-2-O2 5.5 PP-1-2V1 7.0 PY-1-O2 13.0 PYP-2-3 6.0 Σ 100.0

TABLE-US-00041 Mixture M63 B(S)-2O-O4 5.0 Clearing point [° C.]: 74 B(S)-2O-O5 5.0 Δn [589 nm, 20° C.]: 0.1269 B(S)-2O-O6 4.0 Δε [1 kHz, 20° C.]: −2.7 CPP-3-2 4.5 V.sub.0 [V, 20° C.]: 2.44 CC-3-V 34.0 K.sub.1 [pN, 20° C.]: 15.2 CCP-V-1 15.5 K.sub.3 [pN, 20° C.]: 14.3 CLP-3-T 1.0 COB(S)-2-O4 11.0 PP-1-2V1 12.0 PY-1-O2 8.0 Σ 100.0

TABLE-US-00042 Mixture M64 B(S)-2O-O4 5.0 Clearing point [° C.]: 73.7 B(S)-2O-O5 5.0 Δn [589 nm, 20° C.]: 0.1375 B(S)-2O-O6 4.0 Δε [1 kHz, 20° C.]: −2.7 CPP-3-2 7.0 V.sub.0 [V, 20° C.]: 2.44 CC-3-V 28.0 K.sub.1 [pN, 20° C.]: 14.1 CCP-V-1 16.0 K.sub.3 [pN, 20° C.]: 14.4 CLP-3-T 0.5 COB(S)-2-O4 1.0 CPY-2-O2 5.5 PP-1-2V1 7.5 PY-1-O2 12.5 PYP-2-3 8.0 Σ 100.0

TABLE-US-00043 Mixture M65 B(S)-2O-O4 5.0 Clearing point [° C.]: 73.9 B(S)-2O-O5 5.0 Δn [589 nm, 20° C.]: 0.1383 B(S)-2O-O6 4.0 Δε [1 kHz, 20° C.]: −2.6 CPP-3-2 12.0 V.sub.0 [V, 20° C.]: 2.43 CC-3-V 35.0 K.sub.1 [pN, 20° C.]: 15.4 CCP-V-1 3.5 K.sub.3 [pN, 20° C.]: 13.8 CLP-3-T 0.5 COB(S)-2-O4 11.0 PP-1-2V1 12.5 PY-1-O2 5.5 PYP-2-3 6.0 Σ 100.0

TABLE-US-00044 Mixture M66 B(S)-2O-O4 5.0 Clearing point [° C.]: 72.4 B(S)-2O-O5 5.0 Δn [589 nm, 20° C.]: 0.1262 B(S)-2O-O6 4.0 Δε [1 kHz, 20° C.]: −2.6 CC-3-V 35.0 V.sub.0 [V, 20° C.]: 2.46 CC-3-V1 1.0 K.sub.1 [pN, 20° C.]: 15.1 CCP-V-1 16.5 K.sub.3 [pN, 20° C.]: 14.3 CLP-3-T 0.5 COB(S)-2-O4 11.0 PP-1-2V1 12.5 PY-1-O2 6.0 PYP-2-3 3.5 Σ 100.0

TABLE-US-00045 Mixture M67 B(S)-2O-O4 5.0 Clearing point [° C.]: 73.3 B(S)-2O-O5 5.0 Δn [589 nm, 20° C.]: 0.1206 B(S)-2O-O6 4.0 Δε [1 kHz, 20° C.]: −2.6 CC-3-V 36.5 V.sub.0 [V, 20° C.]: 2.44 CC-3-V1 3.0 K.sub.1 [pN, 20° C.]: 14.8 CCP-V-1 16.5 K.sub.3 [pN, 20° C.]: 14.3 CLP-3-T 0.5 COB(S)-2-O4 11.0 PP-1-2V1 9.5 PY-1-O2 6.5 PYP-2-3 2.5 Σ 100.0

TABLE-US-00046 Mixture M68 B(S)-2O-O4 5.0 Clearing point [° C.]: 73.9 B(S)-2O-O5 5.0 Δn [589 nm, 20° C.]: 0.1212 B(S)-2O-O6 4.0 Δε [1 kHz, 20° C.]: −2.7 CPP-3-2 3.5 V.sub.0 [V, 20° C.]: 2.72 CC-3-V 29.5 K.sub.1 [pN, 20° C.]: 13.8 CC-3-V1 8.5 K.sub.3 [pN, 20° C.]: 14.6 CCP-V-1 16.0 CLP-3-T 0.5 CPY-2-O2 9.0 PP-1-2V1 2.0 PY-1-O2 13.0 PYP-2-3 4.0 Σ 100.0

TABLE-US-00047 Mixture M69 B(S)-2O-O4 5.0 Clearing point [° C.]: 73 B(S)-2O-O5 5.0 Δn [589 nm, 20° C.]: 0.1209 B(S)-2O-O6 4.0 Δε [1 kHz, 20° C.]: −2.6 CC-3-V 39.5 V.sub.0 [V, 20° C.]: 2.45 CCP-V-1 16.5 K.sub.1 [pN, 20° C.]: 14.5 CLP-3-T 0.5 K.sub.3 [pN, 20° C.]: 13.9 COB(S)-2-O4 10.5 PP-1-2V1 9.0 PY-1-O2 6.0 PYP-2-3 4.0 Σ 100.0

TABLE-US-00048 Mixture M70 B(S)-2O-O4 4.0 Clearing point [° C.]: 74.4 B(S)-2O-O5 5.0 Δn [589 nm, 20° C.]: 0.1259 B(S)-2O-O6 4.0 Δε [1 kHz, 20° C.]: −2.6 B-2O-O5 3.0 γ.sub.1 [mPa s, 20° C.]: 72 CC-3-V 31.5 CC-3-V1 7.5 CCP-V-1 15.0 CLP-3-T 1.0 COB(S)-2-O4 9.0 PP-1-2V1 10.0 PY-1-O2 3.5 PYP-2-3 6.5 Σ 100.0

TABLE-US-00049 Mixture M71 B(S)—2O—O4 4.0 Clearing point [° C.]: 74.2 B(S)—2O—O5 5.0 Δn [589 nm, 20° C.]: 0.1165 B(S)—2O—O6 4.0 Δϵ [1 kHz, 20° C.]: −2.7 CC-3-V 32.5 γ.sub.1 [mPa s, 20° C.]: 73 CC-3-V1 7.5 CCP—V-1 15.0 CCP—V2-1 4.0 CLP-3-T 0.5 COB(S)-2-O4 10.0 PP-1-2V1 7.5 PY-1-O2 10.0 Σ 100.0

TABLE-US-00050 Mixture M72 B(S)—2O—O4 4.0 Clearing point [° C.]: 73.8 B(S)—2O—O5 5.0 Δn [589 nm, 20° C.]: 0.1170 B(S)—2O—O6 4.0 Δϵ [1 kHz, 20° C.]: −2.6 CC-3-V 36.0 V.sub.0 [V, 20° C.]: 2.51 CC-3-V1 8.0 γ.sub.1 [mPa s, 20° C.]: 71 CCP—V-1 12.5 K.sub.1 [pN, 20° C.]: 14.6 CLP-3-T 1.0 K.sub.3 [pN, 20° C.]: 15.3 COB(S)-2-O4 14.0 PP-1-2V1 10.5 PY-1-O2 5.0 Σ 100.0

TABLE-US-00051 Mixture M73 B(S)—2O—O4 4.0 Clearing point [° C.]: 74.3 B(S)—2O—O5 5.0 Δn [589 nm, 20° C.]: 0.1267 B(S)—2O—O6 4.0 Δϵ [1 kHz, 20° C.]: −2.5 CC-3-V 30.5 V.sub.0 [V, 20° C.]: 2.55 CC-3-V1 8.0 γ.sub.1 [mPa s, 20° C.]: 73 CCP-V-1 14.5 K.sub.1 [pN, 20° C.]: 15.3 CLP-3-T 1.0 K.sub.3 [pN, 20° C.]: 14.8 COB(S)-2-O4 10.0 PP-1-2V1 10.0 PY-1-O2 6.5 PYP-2-3 6.5 Σ 100.0

TABLE-US-00052 Mixture M74 B(S)—2O—O4 4.0 Clearing point [° C.]: 74.1 B(S)—2O—O5 5.0 Δn [589 nm, 20° C.]: 0.1170 B(S)—2O—O6 4.0 Δϵ [1 kHz, 20° C.]: −2.5 CC-3-V 32.5 V.sub.0 [V, 20° C.]: 2.56 CC-3-V1 8.0 γ.sub.1 [mPa s, 20° C.]: 70 CCP—V-1 15.0 K.sub.1 [pN, 20° C.]: 15.2 CCP—V2-1 3.0 K.sub.3 [pN, 20° C.]: 15.1 CLP-3-T 1.0 COB(S)-2-O4 10.0 PP-1-2V1 8.5 PY-1-O2 9.0 Σ 100.0

TABLE-US-00053 Mixture M75 B(S)—2O—O4 4.0 Clearing point [° C.]: 74.3 B(S)—2O—O5 5.0 Δn [589 nm, 20° C.]: 0.1168 B(S)—2O—O6 4.0 Δϵ [1 kHz, 20° C.]: −2.8 CC-3-V 31.5 V.sub.0 [V, 20° C.]: 2.45 CC-3-V1 8.5 γ.sub.1 [mPa s, 20° C.]: 72 CCP—V-1 15.0 K.sub.1 [pN, 20° C.]: 14.9 CCP—V2-1 3.5 K.sub.3 [pN, 20° C.]: 15.0 CLP-3-T 1.0 COB(S)-2-O4 10.0 PP-1-2V1 6.5 PY-1-O2 11.0 Σ 100.0

TABLE-US-00054 Mixture M76 B(S)—2O—O4 4.0 Clearing point [° C.]: 75.3 B(S)—2O—O5 5.0 Δn [589 nm, 20° C.]: 0.1175 B(S)—2O—O6 4.0 Δϵ [1 kHz, 20° C.]: −2.6 CPP-3-2 1.5 γ.sub.1 [mPa s, 20° C.]: 71 CC-3-V 37.5 K.sub.1 [pN, 20° C.]: 14.8 CCP—V-1 15.0 K.sub.3 [pN, 20° C.]: 14.7 CCP—V2-1 5.0 CLP-3-T 1.0 COB(S)-2-O4 10.0 PP-1-2V1 7.5 PY-1-O2 9.5 Σ 100.0

TABLE-US-00055 Mixture M77 B(S)—2O—O4 4.0 Clearing point [° C.]: 75.3 B(S)—2O—O5 5.0 Δn [589 nm, 20° C.]: 0.1176 B(S)—2O—O6 4.0 Δϵ [1 kHz, 20° C.]: −2.8 CC-3-V 36.0 γ.sub.1 [mPa s, 20° C.]: 72 CC-3-V1 1.5 K.sub.1 [pN, 20° C.]: 14.9 CCP—V-1 15.0 K.sub.3 [pN, 20° C.]: 14.7 CCP—V2-1 5.0 CLP-3-T 1.0 COB(S)-2-O4 10.0 CPY-2-O2 1.5 PP-1-2V1 7.0 PY-1-O2 10.0 Σ 100.0

TABLE-US-00056 Mixture M78 B(S)—2O—O4 4.0 Clearing point [° C.]: 74 B(S)—2O—O5 5.0 Δn [589 nm, 20° C.]: 0.1275 B(S)—2O—O6 4.0 Δϵ [1 kHz, 20° C.]: −2.3 CPP-3-2 12.0 γ.sub.1 [mPa s, 20° C.]: 73 CC-3-V 33.5 K.sub.1 [pN, 20° C.]: 15.7 CC-3-V1 8.0 K.sub.3 [pN, 20° C.]: 14.4 CCP-3-1 3.0 CLP-3-T 1.0 COB(S)-2-O4 10.0 PP-1-2V1 10.0 PY-1-O2 7.0 PYP-2-3 2.5 Σ 100.0

TABLE-US-00057 Mixture M79 B(S)—2O—O4 4.0 Clearing point [° C.]: 73.7 B(S)—2O—O5 5.0 Δn [589 nm, 20° C.]: 0.1276 B(S)—2O—O6 4.0 Δϵ [1 kHz, 20° C.]: −2.5 CPP-3-2 11.5 γ.sub.1 [mPa s, 20° C.]: 75 CC-3-V 31.5 K.sub.1 [pN, 20° C.]: 15.7 CC-3-V1 8.0 K.sub.3 [pN, 20° C.]: 14.6 CCP-3-1 5.0 CLP-3-T 1.0 COB(S)-2-O4 10.0 PP-1-2V1 9.5 PY-1-O2 9.5 PYP-2-3 1.0 Σ 100.0

TABLE-US-00058 Mixture M80 B(S)—2O—O4 4.0 Clearing point [° C.]: 74.4 B(S)—2O—O5 5.0 Δn [589 nm, 20° C.]: 0.1274 B(S)—2O—O6 4.0 Δϵ [1 kHz, 20° C.]: −2.5 CC-3-V 36.0 γ.sub.1 [mPa s, 20° C.]: 74 CCP—V-1 15.0 K.sub.1 [pN, 20° C.]: 14.8 CCP—V2-1 1.5 K.sub.3 [pN, 20° C.]: 14.3 CLP-3-T 1.0 COB(S)-2-O4 10.0 PP-1-2V1 9.5 PY-1-O2 6.5 PYP-2-3 7.5 Σ 100.0

TABLE-US-00059 Mixture M81 B(S)—2O—O4 4.0 Clearing point [° C.]: 74.5 B(S)—2O—O5 5.0 Δn [589 nm, 20° C.]: 0.1273 B(S)—2O—O6 4.0 Δϵ [1 kHz, 20° C.]: −2.7 CC-3-V 35.0 γ.sub.1 [mPa s, 20° C.]: 76 CCP—V-1 15.0 K.sub.1 [pN, 20° C.]: 14.8 CCP—V2-1 2.5 K.sub.3 [pN, 20° C.]: 14.2 CLP-3-T 1.0 COB(S)-2-O4 10.0 PP-1-2V1 8.0 PY-1-O2 8.5 PYP-2-3 7.0 Σ 100.0

TABLE-US-00060 Mixture M82 B(S)—2O—O4 4.0 Clearing point [° C.]: 73.9 B(S)—2O—O5 5.0 Δn [589 nm, 20° C.]: 0.1386 B(S)—2O—O6 4.0 Δϵ [1 kHz, 20° C.]: −2.7 CC-3-V 12.5 V.sub.0 [V, 20° C.]: 2.63 CC-3-V1 8.0 γ.sub.1 [mPa s, 20° C.]: 89 CCP-3-1 14.0 K.sub.1 [pN, 20° C.]: 15.4 CCP—V-1 10.0 K.sub.3 [pN, 20° C.]: 16.9 CCP—V2-1 5.0 CLP-3-T 1.0 PP-1-2V1 9.5 PY-1-O2 12.0 PY-2-O2 8.0 PYP-2-3 7.0 Σ 100.0

TABLE-US-00061 Mixture M83 B(S)—2O—O4 4.0 Clearing point [° C.]: 74 B(S)—2O—O5 5.0 Δn [589 nm, 20° C.]: 0.1378 B(S)—2O—O6 4.0 Δϵ [1 kHz, 20° C.]: −2.7 CC-3-V 27.5 V.sub.0 [V, 20° C.]: 2.46 CC-3-V1 8.5 γ.sub.1 [mPa s, 20° C.]: 82 CCP—V-1 10.5 K.sub.1 [pN, 20° C.]: 15.3 CLP-3-T 1.0 K.sub.3 [pN, 20° C.]: 14.6 COB(S)-2-O4 9.5 PP-1-2V1 10.0 PY-1-O2 6.0 PYP-2-3 14.0 Σ 100.0

TABLE-US-00062 Mixture M84 B(S)—2O—O4 4.0 Clearing point [° C.]: 73.8 B(S)—2O—O5 5.0 Δn [589 nm, 20° C.]: 0.1370 CPP-3-2 11.5 Δϵ [1 kHz, 20° C.]: −2.6 BCH-52 4.0 V.sub.0 [V, 20° C.]: 2.44 CC-3-V 27.0 γ.sub.1 [mPa s, 20° C.]: 85 CC-3-V1 8.5 K.sub.1 [pN, 20° C.]: 14.7 CLP-3-T 1.0 K.sub.3 [pN, 20° C.]: 14.2 COB(S)-2-O4 8.5 CPY-2-O2 4.5 PP-1-2V1 8.0 PY-1-O2 11.5 PY-2-O2 1.5 PYP-2-3 5.0 Σ 100.0

TABLE-US-00063 Mixture M85 B(S)—2O—O4 4.0 Clearing point [° C.]: 72.4 B(S)—2O—O5 5.0 Δn [589 nm, 20° C.]: 0.1374 B(S)—2O—O6 4.0 Δϵ [1 kHz, 20° C.]: −2.7 CC-3-V 21.0 V.sub.0 [V, 20° C.]: 2.54 CC-3-V1 9.0 γ.sub.1 [mPa s, 20° C.]: 82 CCP-3-1 1.0 K.sub.1 [pN, 20° C.]: 14.8 CCP—V-1 10.0 K.sub.3 [pN, 20° C.]: 15.5 CCP—V2-1 5.0 CLP-3-T 1.0 CPY-2-O2 9.0 PP-1-2V1 10.0 PY-1-O2 12.0 PYP-2-3 9.0 Σ 100.0

TABLE-US-00064 Mixture M86 B(S)-2O-O4 4.0 Clearing point [° C.]: 71.2 B(S)-2O-O5 5.0 Δn [589 nm, 20° C.]: 0.1368 B(S)-2O-O6 4.0 Δε [1 kHz, 20° C.]: −2.6 CC-3-V 27.5 V.sub.0 [V, 20° C.]: 2.50 CC-3-V1 8.5 γ.sub.1 [mPa s, 20° C.]: 77 CCP-V-1 11.0 K.sub.1 [pN, 20° C.]: 14.4 CLP-3-T 1.0 K.sub.3 [pN, 20° C.]: 14.4 COB(S)-2-O4 7.5 PP-1-2V1 10.0 PY-1-O2 7.5 PYP-2-3 14.0 Σ 100.0

TABLE-US-00065 Mixture M87 B(S)-2O-O4 5.0 Clearing point [° C.]: 75 B(S)-2O-O5 4.0 Δn [589 nm, 20° C.]: 0.1377 B(S)-2O-O6 3.0 Δε [1 kHz, 20° C.]: −2.6 CPP-3-2 11.5 V.sub.0 [V, 20° C.]: 2.47 CC-3-V 22.0 γ.sub.1 [mPa s, 20° C.]: 91 CC-3-V1 8.0 K.sub.1 [pN, 20° C.]: 15.1 CCP-3-1 4.5 K.sub.3 [pN, 20° C.]: 14.5 CLP-3-T 5.0 CPY-2-O2 11.0 PP-1-2V1 3.5 PY-1-O2 12.0 PY-2-O2 5.5 PYP-2-3 5.0 Σ 100.0

TABLE-US-00066 Mixture M88 B(S)-2O-O4 4.5 Clearing point [° C.]: 74.5 B(S)-2O-O5 4.5 Δn [589 nm, 20° C.]: 0.1378 B(S)-2O-O6 3.0 Δε [1 kHz, 20° C.]: −2.6 CPP-3-2 11.5 V.sub.0 [V, 20° C.]: 2.45 CC-3-V 28.0 γ.sub.1 [mPa s, 20° C.]: 86 CCP-3-1 8.0 K.sub.1 [pN, 20° C.]: 14.8 CLP-3-T 3.0 K.sub.3 [pN, 20° C.]: 14.4 CPY-2-O2 11.0 PP-1-2V1 5.5 PY-1-O2 12.0 PY-2-O2 4.0 PYP-2-3 5.0 Σ 100.0

TABLE-US-00067 Mixture M89 B(S)-2O-O4 4.0 Clearing point [° C.]: 74.6 B(S)-2O-O5 5.0 Δn [589 nm, 20° C.]: 0.1375 B(S)-2O-O6 3.0 Δε [1 kHz, 20° C.]: −2.5 CPP-3-2 11.5 V.sub.0 [V, 20° C.]: 2.55 BCH-52 1.5 γ.sub.1 [mPa s, 20° C.]: 83 CC-3-V 30.5 K.sub.1 [pN, 20° C.]: 14.6 CCP-3-1 7.0 K.sub.3 [pN, 20° C.]: 14.6 CLP-3-T 1.0 CPY-2-O2 11.0 PP-1-2V1 8.0 PY-1-O2 12.5 PYP-2-3 5.0 Σ 100.0

TABLE-US-00068 Mixture M90 B(S)-2O-O4 4.0 Clearing point [° C.]: 73 B(S)-2O-O5 5.0 Δn [589 nm, 20° C.]: 0.1376 CPP-3-2 11.5 Δε [1 kHz, 20° C.]: −2.7 BCH-52 2.0 V.sub.0 [V, 20° C.]: 2.42 CC-3-V 26.5 γ.sub.1 [mPa s, 20° C.]: 85 CC-3-V1 8.5 K.sub.1 [pN, 20° C.]: 14.3 CLP-3-T 1.0 K.sub.3 [pN, 20° C.]: 14.3 COB(S)-2-O4 5.5 CPY-2-O2 10.0 PP-1-2V1 8.0 PY-1-O2 12.0 PY-2-O2 1.0 PYP-2-3 5.0 Σ 100.0

TABLE-US-00069 Mixture M91 B(S)-2O-O4 4.0 Clearing point [° C.]: 73.4 B(S)-2O-O5 5.0 Δn [589 nm, 20° C.]: 0.1377 B(S)-2O-O6 3.0 Δε [1 kHz, 20° C.]: −2.7 CPP-3-2 11.0 V.sub.0 [V, 20° C.]: 2.45 CC-3-V 22.5 γ.sub.1 [mPa s, 20° C.]: 84 CC-3-V1 8.0 K.sub.1 [pN, 20° C.]: 14.3 CCP-V-1 8.0 K.sub.3 [pN, 20° C.]: 14.6 CLP-3-T 1.0 CPY-2-O2 11.0 PP-1-2V1 7.0 PY-1-O2 12.0 PY-2-O2 2.5 PYP-2-3 5.0 Σ 100.0

TABLE-US-00070 Mixture M92 B(S)-2O-O4 4.0 Clearing point [° C.]: 74 B(S)-2O-O5 5.0 Δn [589 nm, 20° C.]: 0.1373 B(S)-2O-O6 3.0 Δε [1 kHz, 20° C.]: −2.7 CPP-3-2 11.5 V.sub.0 [V, 20° C.]: 2.45 CC-3-V 29.0 γ.sub.1 [mPa s, 20° C.]: 84 CCP-3-1 9.0 K.sub.1 [pN, 20° C.]: 14.4 CLP-3-T 1.0 K.sub.3 [pN, 20° C.]: 14.6 CPY-2-O2 11.0 PP-1-2V1 7.0 PY-1-O2 12.0 PY-2-O2 2.5 PYP-2-3 5.0 Σ 100.0

TABLE-US-00071 Mixture M93 B(S)-2O-O4 4.0 Clearing point [° C.]: 74.8 B(S)-2O-O5 5.0 Δn [589 nm, 20° C.]: 0.1324 B(S)-2O-O6 3.0 Δε [1 kHz, 20° C.]: −2.7 CPP-3-2 11.5 V.sub.0 [V, 20° C.]: 2.44 CC-3-V 29.5 γ.sub.1 [mPa s, 20° C.]: 81 CC-3-V1 3.5 K.sub.1 [pN, 20° C.]: 14.3 CCP-3-1 8.0 K.sub.3 [pN, 20° C.]: 14.4 CLP-3-T 1.0 CPY-2-O2 11.0 PP-1-2V1 4.0 PY-1-O2 12.0 PY-2-O2 2.5 PYP-2-3 5.0 Σ 100.0

TABLE-US-00072 Mixture M94 B(S)-2O-O4 4.0 Clearing point [° C.]: 74.5 B(S)-2O-O5 5.0 Δn [589 nm, 20° C.]: 0.1486 B(S)-2O-O6 4.0 Δε [1 kHz, 20° C.]: −3.0 CPP-3-2 8.5 V.sub.0 [V, 20° C.]: 2.38 CC-3-V 23.5 γ.sub.1 [mPa s, 20° C.]: 99 CCP-3-1 9.0 K.sub.1 [pN, 20° C.]: 14.8 CCY-3-O2 6.5 K.sub.3 [pN, 20° C.]: 15.5 CLP-3-T 1.0 PP-1-2V1 7.5 PY-1-O2 10.0 PY-3-O2 6.0 PYP-2-3 12.0 PYP-2-4 3.0 Σ 100.0

TABLE-US-00073 Mixture M95 B(S)-2O-O4 4.0 Clearing point [° C.]: 74 B(S)-2O-O5 5.0 Δn [589 nm, 20° C.]: 0.1357 B(S)-2O-O6 4.0 Δε [1 kHz, 20° C.]: −3.0 CC-3-V 31.0 V.sub.0 [V, 20° C.]: 2.38 CCP-3-1 8.0 γ.sub.1 [mPa s, 20° C.]: 89 CCY-3-O2 12.5 K.sub.1 [pN, 20° C.]: 15.0 CLP-3-T 1.0 K.sub.3 [pN, 20° C.]: 15.5 PP-1-2V1 8.0 PY-1-O2 10.5 PYP-2-3 10.0 PYP-2-4 6.0 Σ 100.0

[0488] The media according to the invention are particularly suitable for applications in PS-VA displays as demonstrated in the following Use Examples.

Polymerizable Mixture Examples

Comparative Mixture Example CP1

[0489] Comparative Mixture example CP1 consists of 99.595% of Comparative Mixture C2, 0.40% of the compound RM-1

##STR00531##

and 0.005% of the compound ST-3a-1

##STR00532##

Comparative Mixture Example CP2

[0490] Comparative Mixture example CP2 consists of 99.595% of Comparative Mixture C3, 0.40% of the compound RM-1

##STR00533##

and 0.005% of the compound ST-3a-1

##STR00534##

Comparative Mixture Example CP3

[0491] Comparative Mixture example CP3 consists of 99.595% of Comparative Mixture C4, 0.40% of the compound RM-1

##STR00535##

and 0.005% of the compound ST-3a-1

##STR00536##

Mixture Example P1

[0492] Mixture example P1 consists of 99.595% of Mixture M-10, 0.40% of the compound RM-1

##STR00537##

and 0.005% of the compound ST-3a-1

##STR00538##

Mixture Example P2

[0493] Mixture example P2 consists of 99.595% of Mixture M-11, 0.40% of the compound RM-1 and 0.005% of the compound ST-3a-1.

Mixture Example P3

[0494] Mixture example P3 consists of 99.595% of Mixture M-12, 0.40% of the compound RM-1 and 0.005% of the compound ST-3a-1.

Mixture Example P4

[0495] Mixture example P4 consists of 99.595% of Mixture M-13, 0.40% of the compound RM-1 and 0.005% of the compound ST-3a-1.

Mixture Example P5

[0496] Mixture example P5 consists of 99.595% of Mixture M-14, 0.40% of the compound RM-1 and 0.005% of the compound ST-3a-1.

Mixture Example P6

[0497] Mixture example P6 consists of 99.595% of Mixture M-14, 0.40% of the compound RM-19 and 0.005% of the compound ST-3a-1.

##STR00539##

Mixture Example P7

[0498] Mixture example P7 consists of 99.595% of Mixture M-14, 0.40% of the compound RM-19

##STR00540##

and 0.005% of the compound ST-3b-1

##STR00541##

Mixture Example P8

[0499] Mixture example P8 consists of 99.595% of Mixture M-14, 0.40% of the compound RM-35

##STR00542##

and 0.005% of the compound ST-3a-1

##STR00543##

Use Example A

[0500] The media are investigated with respect to their applicability for polymer stabilized displays of the VA type (PS-VA).

[0501] The polymerizable mixtures shown above are filled into PSA test cells, the RM is polymerized under application of a voltage, and several properties like residual RM content, VHR after stress and tilt angle generation are measured.

[0502] VHR Measurements

[0503] The VHR values of polymerizable mixtures CP1, CP2 and P5 are measured at 60° C. in VA-VHR test cells before and after UV exposure for 80 min at room temp. using a fluorescent UV lamp type C (305 nm˜355 nm) followed by a CCFL backlight (BL) load for up to 12 days. The results are shown in Table 2.

TABLE-US-00074 TABLE 2 VHR values CP1 CP2 P5 VHR at 60° C. (%) VHR/% Initial 99.6 99.6 99.5 After 80 min UV 74.2 89.6 91.4 After 1 d BL 95.8 94.0 96.5 After 5 d BL 85.9 88.4 93.8 After 12 d BL — 73.6 88.9

[0504] The compositions of the media CP1, CP2 and P5 are very similar in terms of physical parameters and mixture components and differ only in the presence of the compound CLP-3-T. From Table 2 it can be seen that the initial VHR values of the polymerizable mixtures CP1, CP2 and P5 are approximately at the same level. After UV exposure the mixtures CP1 and CP2 show a significant decrease of the VHR, whereas the medium P5 maintains a high VHR even after 12d of backlight load.

[0505] The mixture P5 with higher VHR after UV exposure is thus especially suitable for PSA displays with high reliability and UV stability.

[0506] Pretilt

[0507] During the PS-VA process a tilt angle is generated by a UV-initiated polymerization of the reactive mesogens. Each of polymerizable mixtures CP3 and P5 is inserted into a VA e/o test cell. The test cells comprise a VA-polyimide alignment layer (JALS-2096-R1) which is rubbed antiparallel. The LC-layer thickness d is approx. 4 μm.

[0508] The pretilt angle is determined after UV irradiation with 50 mW/cm.sup.2 for up to 120s (energy dose 6J) by a crystal rotation experiment (Autronic-Melchers TBA-105). The results are shown in Table 3.

TABLE-US-00075 TABLE 3 Tilt angle after UV load Tilt Tilt Tilt after after after Mixture 1J 3J 6J CP3 89.1 88.4 86.3 P5 89.3 88.3 85.0

[0509] It can be seen that the tilt angles generated with the medium P5 is comparable to the values observed for the comparative medium CP3 from the state of the art.

[0510] Polymerization Rate

[0511] The polymerization rate is measured by determining the residual content of residual, unpolymerized RM (in % by weight) in the mixture after UV exposure with a given intensity and lamp spectrum after a given UV exposure time. The smaller the residual RM content after a given time interval, the faster the polymerization. For this purpose the polymerizable mixtures are filled into electrooptic test cells made of soda lime glass coated with an approximately 200 nm thick layer of ITO and a 30 nm layer of VA-polyimide from Varitronix with a cell gap of 6-7 μm. The test cells are illuminated with a fluorescent UV lamp type C (305 nm to 355 nm), causing polymerization of the RM. Illumination times are given in the tables below.

[0512] After polymerization the test cells are opened, and the mixture is dissolved and rinsed out of the test cell with 2 ml ethyl methyl ketone and analyzed by High Performance Liquid Chromatography (HPLC). The results are shown in Table 4.

TABLE-US-00076 TABLE 4 residual RM Mixture UV Time/min 40 80 CP3 residual RM/% 0.0256 0.0076 P5 0.0143 0.0043

[0513] From Table 4 it can be seen that the polymerization rate of the medium P5 according to the invention is advantageously high and suitable for industrial application.