Reflective liquid crystal panel

Abstract

To provide LCoS panels using liquid crystal (LC) media having negative dielectric anisotropy, and the LC media comprised therein.SOLUTION: A liquid crystal medium (LC medium) disclosed herein is a negative dielectric anisotropy liquid crystal material having high optical anisotropy. The medium is particularly useful in electro-optical displays including projection systems based on vertical alignment (VA) nematic panels.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a liquid crystal on silicon panel (LCoS panel) using a liquid crystal (LC) medium having negative dielectric anisotropy and the LC medium included therein. Currently disclosed liquid crystal media (LC media) have negative dielectric anisotropy and high optical anisotropy and are particularly useful in electro-optical displays including projection systems based on vertically aligned (VA) nematic panels.

Background Art

[0002] LCoS panels are used as reflective matrix arrays in devices such as projection systems, near-eye displays or beam steering applications. In the most common mode, the display modulates the direction of polarization (amplitude modulation), like most conventional LC displays. In some applications of LCoS, controlled phase modulation of coherent light is utilized to control the spatial distribution of light rays, including image projection. Considering new applications and light sources, there is room for improvement in many areas in the development of LCoS panels.

[0003] The alignment layer is usually applied on the electrode (if such an electrode exists) to contact the LC medium and induces an initial alignment of the LC molecules. The alignment layer in an LCoS panel often consists of an inorganic alignment material that is more heat-resistant than the polyimide layer mainly used in other LC panels for desktop and television applications. Careful testing is required for the variable alignment characteristics of these inorganic materials. For LCoS panels, there is a need for LC media with high alignment characteristics for inorganic alignment materials. In addition, these devices usually require high light stability and long life under high light intensity.

[0004] Another problem observed in the prior art is that the use of conventional LC media in LCoS panels often results in the generation of bubbles and ultimately dark defects in the display due to the severe temperature and irradiation during use. Therefore, it is desirable to provide an LC media that results in a reduction of displacement defects after continuous use. This means that they must be stable by themselves and must be well combined with adjacent materials, such as the alignment layer, for example.

[0005] Another problem observed in the prior art is that LC media for use in displays, including but not limited to LCoS-type displays, often exhibit high viscosities and, as a result, have long switching times. In addition, there is a great demand for displays and LC media for use in such displays that have a wide operating temperature range, short response times, and low threshold voltages, multiplicity of gray shades, high contrast, high reliability, and high values of VHR after UV irradiation, in combination with high specific resistance. SUMMARY OF THE INVENTION

[0006] The present invention is based on the object of providing a novel and suitable LC media for use in devices that do not have the above-mentioned drawbacks or have them to a reduced extent. The present invention further has the object of providing an LCoS panel that does not have the above-mentioned drawbacks or has them to a reduced extent and at the same time has low viscosity, high birefringence, negative dielectric anisotropy, high transmittance or high reflectivity, and a high clearing point.

[0007] In particular, the present invention is based on the object of providing an LC media that reduces or prevents the generation of bubbles and dark defects in a display. These objects have been achieved according to the present invention by the materials and processes described in the present application. In particular, surprisingly, it has been found that by using the liquid crystal host described below, it is possible to achieve the advantageous effects as described above.

[0008] On one side, the present invention relates to an LCoS panel comprising an LC medium containing one or more compounds represented by formula IV,

Chemical formula

Chemical formula

[0009] The present invention further relates to a liquid crystal medium comprising: a) one or more compounds represented by formula IV

Chemical formula

Chemical formula

Chemical formula

Chemical formula

Chemical formula

Chemical formula

Chemical formula

Chemical formula

[0010] The medium may more preferably contain one or more compounds selected from groups d) and e): d) Formulas IIA, IIB, IIC, IID and IIE, [Chemical formula] wherein, R 2A , R 2B , R 2C , R 2D , R 2E1 and R 2E2 each independently represents H, an alkyl radical having 1 to 7 carbon atoms, or an alkenyl radical having 2 to 7 carbon atoms, each of which is unsubstituted or mono-substituted with at least halogen, where one or more CH 2 groups in these radicals may each be replaced in a way that O atoms are not directly linked to each other by -O-, -S-, [Chemical formula] -C≡C-, -CF 2 O-, -OCF 2 -, -OC-O- or -O-CO-; L 1 and L 2 each independently represents F, Cl, CF 3 or CHF 2 ; Y represents H, F, Cl, CF 3 , CHF 2 or CH 3 ; Z 2 , Z 2B and Z 2D each independently represents a single bond, -CH 2 CH 2 -, -CH=CH-, -CF 2 CF 2 -, -CF=CF-, -CF 2 O-, -OCF 2 -, -CH 2 O-, -OCH 2 -, -COO-, -OCO-; p represents 0, 1, or 2, q represents 0 or 1, and v represents 1, 2, 3, 4, 5, or 6, and, e) Formula III,

Chemical formula

Chemical formula

[0011] The present invention further relates to a process for preparing an LC medium as described above and below, the process comprising the step of mixing one or more compounds represented by formulae I, IV-2 and ST-1, optionally together with further LC compounds and / or additives. The present invention further relates to a projection device comprising an LCoS panel and a light guiding element according to the present invention. The light guiding element can be selected from a lens, a mirror, a half mirror, a prism or the like.

[0012] The present invention further relates to the use of an LC medium according to the present invention in a display. The present invention further relates to an LC display comprising an LC medium according to the present invention of the IPS, FFS, UB-FFS, UBplus, VA, or PS-VA type. The present invention further relates to the use of an LC medium according to the present invention in a polymer stabilized VA or self-aligned VA display, and to a polymer stabilized VA display comprising an LC medium according to the present invention.

[0013] The present invention further relates to a VA-type or PSA-type LC display comprising two substrates, at least one of which is transparent to light, electrodes provided on each substrate or two electrodes provided on only one of the substrates, and a layer of an LC medium comprising one or more polymerizable compounds and LC constituents as described above and below, wherein the polymerizable compound is polymerized between the substrates of the display.

[0014] The present invention further relates to a VA-type LC display comprising two opposing substrates, one being transparent and the other being a silicon semiconductor backplane. The present invention further relates to a process for manufacturing an LCoS panel as described above and below, comprising the step of filling or otherwise providing an LC medium as described above and below between the substrates of the panel, and the step of sealing it.

Embodiments for Carrying Out the Invention

[0015] Preferred embodiments are also disclosed in the dependent claims and their combinations. A display according to the present invention preferably has two electrodes in the form of transparent layers, which are applied to one or both substrates. In a typical reflective display, a continuous transparent electrode is applied to a transparent substrate. The opposite electrode is formed as individually addressable pixels.

[0016] Surprisingly, it has been found that the use of a liquid crystal medium according to the present invention enables the realization of a display with fast response times, low threshold voltages, and high birefringence, as well as high reliability even when exposed to radiation and thermal stress. In particular, the medium according to the present invention is characterized by good alignment properties with various alignment materials.

[0017] When used in a VA or FFS display, the LC medium according to the present invention exhibits the following advantageous properties: - Improvement in the transmittance of the display, - High clearing temperature, - Sufficient stability against heat and / or UV, - High voltage holding ratio, - Relatively fast switching, and - Good LTS.

[0018] When used in a reflective display including a projection system, the LC medium according to the present invention exhibits the following advantageous properties: - High clearing temperature, - Relatively fast switching, - Sufficient stability against heat, light, and / or UV, and - Excellent alignment on an inorganic alignment material.

[0019] In particular, the liquid crystal medium according to the present invention advantageously has a ratio γ of the rotational viscosity to the spray elastic constant that is low 1 / K 1 This contributes, among other things, to an improvement in the switching behavior at low driving voltages and is useful for realizing an energy-saving display. In the following, the essential and optional components of the LC medium are disclosed in more detail with respect to preferred embodiments of the media and LC displays containing them.

[0020] The preferred compounds represented by Formulas IIA, IIB, IIC, IID, and IIE are shown below:

Chemical formula

Chemical formula

Chemical formula

Chemical formula

Chemical formula

Chemical formula

Chemical formula

Chemical formula

Chemical formula

Chemical formula

Chemical formula

[0021] Alkenyl is preferably CH 2 =CH-, CH 2 =CHCH 2 CH 2 -, CH 3 -CH=CH-, CH 3 -CH 2 -CH=CH-, CH 3 -(CH 2 ) 2 -CH=CH-, CH 3 -(CH 2 ) 3 -CH=CH-, or CH 3 -CH=CH-(CH 2 ) 2 - and represents any one of the groups.

[0022] The compounds represented by highly preferred Formula IID are selected from the following sub-formulas: [Chemical formula] [Chemical formula] [Chemical formula] [Chemical formula] [Chemical formula] Here, v represents 1, 2, 3, 4, 5 or 6.

[0023] In a preferred embodiment, the medium comprises one or more compounds represented by formula IID-12a,

Chemical formula

Chemical formula

[0024] In a preferred embodiment, the medium comprises one or more compounds represented by the following formula IIE:

Chemical formula

Chemical formula

[0025] Highly preferred media according to the present invention comprise one or more compounds represented by formula IIB-2,

Chemical formula

Chemical formula

[0026] Preferred media according to the invention preferably contain a compound of formula IIC-1 in an amount of from 0.5 to 5% by weight, in particular from 1 to 3% by weight,

Chemical formula

[0027] In particular, the medium contains one or more compounds of formula IIA-2 selected from the following sub-formulas:

Chemical formula

[0028] Alternatively, preferably, in addition to the compounds of formula IIA-2-1 to IIA-2-5, the medium contains one or more of the compounds of formula IIA-2a-1 to IIA-2a-5:

Chemical formula

[0029] In particular, the medium contains one or more compounds of formula IIA-10 or IIA-52 selected from the following sub-formulas:

Chemical formula

Chemical formula

[0030] Alternatively, preferably, in addition to the compounds of formula IIA-10-1 to IIA-10-5, the medium contains one or more of the compounds of formula IIA-10a-1 to IIA-10a-5:

Chemical formula

Chemical formula

[0031] In particular, the medium comprises one or more compounds represented by Formula IIB-10 selected from the following sub-formulas:

Chemical formula

[0032] Alternatively, preferably, in addition to the compounds represented by Formulas IIB-10-1 to IIB-10-5, the medium comprises one or more of the compounds represented by Formulas IIB-10a-1 to IIB-10a-5:

Chemical formula

Chemical formula

[0033] Most preferably, the medium according to the present invention comprises one or more compounds represented by Formula IIE, especially the compounds represented by Formulas IIE-1-1 to IIE-1-8, and most preferably one or more of the compounds represented by Formulas IIE-1-1-1 to IIE-1-1-4:

Chemical formula

[0034] The compound represented by Formula III is preferably selected from the compounds represented by Formulas III-1, III-2 and / or III-4,

Chemical formula

Chemical formula

[0035] The liquid crystal medium according to the invention preferably contains one, two or more compounds represented by formula III-2. In a preferred embodiment, the liquid crystal medium contains at least one compound represented by formula III-1 and at least one compound represented by formula III-2. In an even more preferred embodiment, the liquid crystal medium contains at least one compound represented by formula III-2 and at least one compound represented by formula III-3.

[0036] Preferably, the compound represented by formula III-1 is selected from the group of compounds represented by formulas III-1-1 to III-1-10, preferably the compound represented by formula III-1-6,

Chemical formula

Chemical formula

[0037] Preferably, the compound represented by formula III-2 is selected from the group of compounds represented by formulas III-2-1 to III-2-10, preferably the compound represented by formula III-2-6, [Chemistry] [Chemistry] In the formula, alkyl and alkyl* each independently represent a linear alkyl radical having 1 to 6 carbon atoms, alkenyl and alkenyl* each independently represent a linear alkenyl radical having 2 to 6 carbon atoms, alkoxy and alkoxy* each independently represent a linear alkoxy radical having 1 to 6 carbon atoms, and 31 and 32 each independently represent F or Cl, preferably both are F.

[0038] Optionally, the medium contains one or more compounds represented by formula IIIA-1 and / or IIIA-2, [Chemistry] In the formula, 31 and 32 have the same meaning as given under formula III, (O) represents O or a single bond, R IIIA represents alkyl or alkenyl having up to 7 carbon atoms, or the group Cy-C m H 2m+1 represents, m and n are the same or different and are 0, 1, 2, 3, 4, 5 or 6, preferably 1, 2 or 3, and most preferably 1, Cy represents a cycloaliphatic group having 3, 4 or 5 ring atoms, which may be optionally substituted with alkyl or alkenyl each having up to 3 carbon atoms, or halogen or CN, and preferably represents cyclopropyl, cyclobutyl, cyclopentyl or cyclopentenyl.

[0039] The compound represented by formula IIIA-1 and / or IIIA-2 is preferably additionally contained in the medium, instead of or in addition to the compound represented by formula III.

[0040] Highly preferred compounds represented by formulas IIIA-1 and IIIA-2 are as follows:

Chem.

[0041] In a preferred embodiment of the present invention, the medium contains one or more compounds represented by formula III-3,

Chem.

Chem.

[0042] The compound represented by formula III-3 is preferably selected from the group of compounds represented by formulas III-3-1 to III-3-10:

Chem.

[0043] In a preferred embodiment of the present invention, the medium contains one or more compounds represented by formulas III-4 to III-6, preferably the compound represented by formula III-5, [Chemical formula] In the formula, the parameters have the meanings given above, and R 31 preferably represents a linear alkyl having 1 to 7 C atoms, and R 32 preferably represents an alkoxy having 1 to 7 C atoms.

[0044] In a preferred embodiment, the medium according to the present invention contains one or more compounds represented by formula III, preferably selected from the group of compounds represented by formulas III-7 to III-9, more preferably the one represented by formula III-8, [Chemical formula] In the formula, the parameters have the meanings given above, and R 31 preferably represents a linear alkyl having 1 to 7 C atoms, and R 32 preferably represents an alkoxy having 1 to 7 C atoms.

[0045] In a preferred embodiment, the medium contains one or more compounds represented by formula IV, [Chemical formula] In the formula, R 41 represents an unsubstituted alkyl radical having 1 to 7 carbon atoms or an unsubstituted alkenyl radical having 2 to 7 carbon atoms, preferably an n-alkyl radical, particularly preferably having 2, 3, 4 or 5 carbon atoms, R 42 represents an unsubstituted alkyl radical having 1 to 7 carbon atoms or an unsubstituted alkoxy radical having 1 to 6 carbon atoms (both preferably having 2 to 5 carbon atoms), an unsubstituted alkenyl radical having 2 to 7 carbon atoms (preferably having 2, 3 or 4 carbon atoms), more preferably a vinyl radical or a 1-propenyl radical, particularly a vinyl radical, provided that the compound represented by formula I is excluded from formula IV and its sub-formulas.

[0046] The compound represented by formula IV is preferably selected from the group of compounds represented by formulas IV-1 to IV-4,

Chemical formula

Chemical formula

[0047] Preferably, the medium contains, in addition to the compound represented by formula IV-2, one or more compounds selected from the compounds represented by formulas IV-1 and IV-3. Preferably, the medium comprises one or more compounds selected from the compounds represented by Formulas IV-1-1 to IV-1-4 [Chemical formula] and the like.

[0048] Most preferably, the medium according to the present invention comprises the compound represented by Formula IV-1-1. Most preferably, the medium according to the present invention comprises one or more compounds represented by Formula IV-2-1 and / or IV-2-2 [Chemical formula] [Chemical formula] and the like.

[0049] In a preferred embodiment, the medium according to the present invention comprises one or more compounds represented by Formula IV-3, [Chemical formula] wherein, most preferably, alkyl is an alkyl group preferably having 1 to 7 C atoms, particularly n-ethyl or n-propyl, very specifically n-propyl, and alkenyl is [Chemical formula] where m is 0, 1 or 2, preferably 0, and n is 0, 1 or 2, preferably 0 or 1, In particular, the compounds represented by Formulas IV-3-1 to IV-3-6, very particularly preferably the compound represented by Formula IV-3-2: [Chemical formula] selected from.

[0050] In a preferred embodiment, the medium comprises, in particular in addition to the compounds represented by Formulas IV-3-1 to IV-3-6, one or more of the compounds represented by Formulas IV-3-7 to IV-3-9. [Chemical formula]

[0051] Preferably, the concentration of the compound represented by Formulae IV-3-7 to IV-3-9 in the medium according to the present invention is less than 5%, or less than 4%, or less than 3%, and most preferably, it is 0% to 1%, especially 0%. Most preferably, the medium according to the present invention contains one or more compounds represented by Formula IV-3 and one or more compounds represented by Formula IV-1, and the total concentration of the compound represented by Formula IV-1 therein is in the range of 1% to 30%.

[0052] Most preferably, the medium according to the present invention contains a compound of Formula IV-4, particularly a compound selected from the compounds represented by Formulae IV-4-1 to IV-4-3, especially the one represented by Formula IV-4-3. [Chemical formula]

[0053] In a preferred embodiment, the medium according to the present invention contains one or more compounds represented by Formula I selected from the compounds represented by Formulae I-1 to I-4 in combination with one or more compounds selected from the group of compounds represented by Formulae IA-1 to IA-18: [Chemical formula] [Chemical formula] [Chemical formula] In the formula, alkyl represents methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, or n-pentyl.

[0054] The LC medium according to the present invention preferably contains one or more compounds represented by Formula IVa, [Chemical formula] In the formula, R 41 and R 42 each independently represents a linear alkyl, alkoxy, alkenyl, alkoxyalkyl or alkenyloxy radical having up to 12 carbon atoms, and

Chemical formula

Chemical formula

[0055] Preferred compounds represented by formula IVa are shown below:

Chemical formula

[0056] The medium according to the invention preferably contains at least one compound represented by formula IVa-1 and / or formula IVa-2, very preferably a compound represented by formula IVa-2, especially compound IVa-2 in which alkyl represents n-propyl and alkyl* represents methyl. The proportion of the compound represented by formula IVa in the whole mixture is preferably less than 5% by weight, very preferably less than 2% by weight.

[0057] Preferably, the medium contains one or more compounds represented by Formulas IVb-1 to IVb-3, [Chemical Formula] wherein, alkyl and alkyl* each independently represent a linear alkyl radical having 1 to 6 carbon atoms, and alkenyl and alkenyl* each independently represent a linear alkenyl radical having 2 to 6 carbon atoms.

[0058] The proportion of the compounds represented by Formulas IV-1 to IV-3 in the entire mixture is preferably less than 3% by weight, especially less than 2% by weight. Among the compounds represented by Formulas IVb-1 to IVb-3, the compound represented by Formula IVb-2 is particularly preferred.

[0059] A very particularly preferred biphenyl is [Chemical Formula] wherein alkyl* represents an alkyl group having 1 to 6 carbon atoms and preferably represents n-propyl or n-butyl. The medium according to the present invention particularly preferably contains one or more compounds represented by Formula IVb-1-1 and / or IVb-2-3. In the compound represented by Formula IVb-1-1, alkyl preferably represents propyl, butyl and pentyl, and most preferably represents propyl.

[0060] In a preferred embodiment, the medium according to the present invention contains one or more compounds represented by Formula V, [Chemical Formula] wherein, R 51 、R 52 represents alkyl having 1 to 7 carbon atoms, alkoxy having 1 to 7 carbon atoms, or alkoxyalkyl, alkenyl or alkenyloxy having 2 to 7 carbon atoms,

Chem.

Chem.

Chem.

Chem.

[0061] The compound represented by formula V is preferably selected from the compounds represented by formulas V-1 to V-14:

Chem.

Chem.

[0062] R 51 and R 52 preferably each independently represent a linear alkyl having 1 to 7 C atoms or an alkenyl having 2 to 7 C atoms. Preferred media include one or more of the compounds represented by formulas V-1, V-3, V-4, V-6, V-7, V-10, V-11, V-12 and / or V-14.

[0063] In a preferred embodiment, the medium according to the present invention comprises one or more compounds represented by formula Vb, [Chemical formula] wherein, R 51 and R 52 each represents alkyl having 1 to 7 carbon atoms, alkoxy having 1 to 7 carbon atoms, or alkoxyalkyl, alkenyl or alkenyloxy having 2 to 7 carbon atoms, [Chemical formula] represents [Chemical formula] and [Chemical formula] represents [Chemical formula] and Z 51 and Z 52 each independently represents -CH 2 -CH 2 -, -CH 2 -O-, -CH=CH-, -C≡C-, -COO- or a single bond, and n is 2.

[0064] The compound represented by formula Vb is preferably selected from the compounds represented by formulas Vb-1 to Vb-2: [Chemical formula]

[0065] In a preferred embodiment of the present invention, the medium further comprises one or more compounds represented by formula VI, [Chemical formula] wherein, R6 and R 62 has the meaning of R as defined in claim 1 2A and R 62 is alternatively F, Cl, CF 3 or OCF 3 , preferably represents F, L 61 , L 62 , L 63 , L 64 , L 65 , and L 66 each independently represents H or F, where L 61 , L 62 , L 63 , L 64 , L 65 , and L 66 at least one of which represents F, and wherein the compounds represented by Formulas IIC and IIE are excluded.

[0066] The compound represented by Formula VI is preferably selected from Formulas VI-1 to VI-20, especially from Formulas VI-1, VI-2, IV-4, VI-14, VI-19 and VI-20:

Chemical formula

Chemical formula

Chemical formula

[0067] R 6 preferably represents methyl, ethyl, propyl, butyl, pentyl, hexyl, methoxy, ethoxy, propoxy, butoxy or pentoxy. Particularly preferred are the compounds represented by Formulas VI-1, VI-2, VI-4, VI-19 and VI-20.

[0068] In a preferred embodiment of the present invention, the medium further comprises one or more compounds represented by formula VIA,

Chemical formula

[0069] Most preferably, the medium according to the present invention comprises a compound represented by formula VIA-1 and / or formula X,

Chemical formula

[0070] In a preferred embodiment of the present invention, the medium additionally comprises one or more of the compounds represented by Formulas VII-1 to VII-9,

Chemical formula

Chemical formula

[0071] Even more preferred embodiments are listed below: a) A liquid crystal medium comprising at least one compound represented by Formulas Z-1 to Z-8

Chemical formula

Chemical formula

[0072] b) Preferred liquid crystal media according to the present invention comprise one or more substances containing tetrahydronaphthyl or naphthyl units, such as compounds represented by Formulas N-1 to N-5, for example,

Chemical formula

[0073] c) A preferred mixture contains one or more compounds selected from the group consisting of a difluorodibenzochroman compound represented by formula BC, a chroman represented by formula CR, and a fluorinated phenanthrene represented by formulas PH-1 and PH-2,

Chemical formula

Chemical formula

[0074] Particularly preferred compounds represented by formulas BC and CR are compounds BC-1 to BC-7 and CR-1 to CR-5,

Chemical formula

Chemical formula

[0075] d) Preferred mixtures contain one or more indane compounds of formula In,

Chemical formula

Chemical formula

Chemical formula

[0076] The preferred compounds represented by formula In are the compounds represented by formulas In-1 to In-16 shown below:

Chem.

Chem.

Chem.

[0077] e) The preferred mixture further contains one or more of the compounds represented by formulas L-1 to L-12,

Chem.

Chem.

[0078] f) The preferred mixture additionally contains one or more compounds represented by formula IIA-Y,

Chem.

[0079] The preferred compounds represented by formula IIA-Y are selected from the group consisting of the following sub-formulas:

Chemical formula

Chemical formula

Chemical formula

[0080] Particularly preferred compounds represented by formula IIA-Y are selected from the group consisting of the following sub-formulas:

Chemical formula

[0081] g) The medium additionally contains one or more compounds selected from the compounds represented by formulas P-1 to P-4:

Chemical formula

Chemical formula

[0082] The preferred compounds represented by Formulas P1 to P4 are listed below:

Chemical formula

[0083] The compound represented by Formula P-1 has the property of stabilizing for a liquid crystal medium. In a preferred embodiment, the medium according to the present invention contains at least one compound represented by Formula P-1, more preferably a compound represented by Formula P-1a, preferably in an amount of 0.1 to 5% by weight, more preferably 0.4 to 2.5% by weight.

[0084] h) The medium additionally contains one or more compounds selected from the group consisting of Formulas PII and PIII:

Chemical formula

Chem.

Chem.

Chem.

Chem.

Chem.

Chem.

[0085] The preferred compound represented by formula PIII is the one represented by formula PIII-1, [Chemical formula] wherein R 3 represents an unsubstituted or halogenated linear or branched alkyl radical having 1 to 15 carbon atoms, and one or more CH 2 groups in these radicals are each independently [Chemical formula] -C≡C-, -CF 2 O-, -CH=CH-, -O-, -CO-O- or -O-CO- may each be replaced in such a way that O atoms are not directly linked to each other, L 31 and L 32 are the same or different and represent H or F, preferably F, Y 3 are the same or different and represent H or CH 3 and X 3is, independently of one another, halogen, CN, haloalkyl or alkoxy having 1 to 3 C atoms, or haloalkenyl or alkenyloxy having 2 or 3 C atoms, preferably F, CN, OCF 3 or CF 3 and most preferably F or CN, and n is independently 0 or 1, preferably n is 0.

[0086] Preferably, in PIII and PIII-1, the groups independently represent one or more of the following: X 3 represents CN, L 31 represents F, L 32 represents H, n represents 0, L 33 L 34 represents H, and Y 3 represents H.

[0087] Preferably, the liquid crystal medium according to the invention comprises one or more compounds of formula H, [Chemical formula] wherein A is a q-valent aliphatic, aromatic or heteroaromatic hydrocarbon group having 1 to 40 C atoms, preferably 6 to 30 C atoms; or represents a bond with q = 2; Sp represents a spacer group or a bond; R S represents H, alkyl having 1 to 12 C atoms, or alkenyl having 2 to 12 C atoms; Z S is -O-, -C(O)O-, -(CH 2 ) z - or -(CH 2 ) z O- or a single bond; preferably -C(O)O-, HA is [Chemical formula] represents R H is H, O·, CH 3 , OH or OR S represents, preferably H or O·, R S1 , R S2 , R S3 and R S4 are the same or different and represent alkyl having 1 to 6 C atoms, preferably 1 to 3 C atoms, and most preferably CH 3 is G is H or R S or group Z S -HA represents Group z is an integer from 1 to 6, q is 1, 2, 3 or 4, preferably 2.

[0088] In formula H, aryl preferably represents an aromatic or heteroaromatic hydrocarbon group having 4 to 40 C atoms containing 1, 2, 3 or 4 aromatic rings (including fused rings which may be linked directly or via an alkylene linking group having 1 to 12 C atoms), where one or more H atoms are alkyl or alkoxy having 1 to 6 C atoms, or alkenyl having 2 to 6 C atoms, or are optionally replaced by CN, CF 3 or halogen, and where one or more CH 2 groups are each optionally replaced, independently of one another, in such a way that O or S atoms are not directly linked to one another by -O-, -S-, -NH-, -N(C 1 ~C 4 alkyl)-, -CO-, -CO-O-, -O-CO-, -O-CO-O-, -CH=CH- or -C≡C-.

[0089] Preferred aliphatic groups are alkylene, cycloalkylene, more preferably -(CHR S5 ) s -, where R S5is H or alkyl having 1 to 5 C atoms, and s is an integer from 1 to 20. Preferred aryl groups are benzene, naphthalene, anthracene, biphenyl, m - terphenyl, p - terphenyl, and (phenylalkyl)benzenes where the alkyl is a straight - chain alkyl having 1 to 12 C atoms. The compound represented by formula H is described in EP 3354710 A1 and EP 3354709 A1. The compound represented by formula H is preferably applied in the range of 0.1 to 0.3% (by weight).

[0090] In a preferred embodiment, the medium comprises one or more compounds represented by formula H selected from compounds represented by

Chemical formula

[0091] Group A a is preferably

Chemical formula

[0092] The compound represented by formula H is preferably selected from the compounds represented by formulas H-1, H-2 and H-3: [Chemical formula] [Chemical formula] [Chemical formula] Here, R H has the meaning given above, and preferably represents H or O·, and, n is an integer from 0 to 12, preferably 5, 6, 7, 8 or 9, most preferably 7, and Sp represents a spacer group, preferably an alkylene having 1 to 12 C atoms in which one or more non-adjacent -CH 2 - groups may be replaced by -O-.

[0093] The preferred compound represented by formula H-10 is selected from the compounds represented by formula H-10-1: [Chemical formula] Here, R Hhas the meaning given above and preferably represents H or O·, and n is an integer from 0 to 12, preferably 5, 6, 7, 8 or 9, and most preferably 7.

[0094] The preferred compounds represented by formula H-11 are selected from the compounds represented by formula H-11-1:

Chemical formula

[0095] The preferred compounds represented by formula H-12 are selected from the compounds represented by formula H-12-1:

Chemical formula

[0096] The preferred stabilizer H is as follows:

Chemical formula

Chemical formula

[0097] Preferably, the medium according to the present invention contains a compound selected from the group of compounds represented by formulas ST-1 to ST-12: [Chemical formula] [Chemical formula] In the formula, R ST represents H, an alkyl or alkoxy radical having 1 to 15 C atoms, where, in addition, one or more CH 2 groups are, independently of one another, replaced by -C≡C-, -CF 2 O-, -OCF 2 -, -CH=CH-, [Chemical formula] -O-, -CO-O-, -O-CO- in such a way that the O atoms are not directly linked to each other, and where one or more H atoms may be replaced by halogen, preferably an alkyl or cyclopentyl having 1 to 7 C atoms, [Chemical formula] is, in each occurrence, the same or different, [Chemical formula] represents, Z ST is, independently of one another, -CO-O-, -O-CO-, -CF 2 O-, -OCF 2 (-), -CH 2 O-, -OCH 2 (-), -CH 2 (-), -CH 2 CH 2 (-), -(CH 2 ) 4 (-), -CH=CH-, -CH 2 O-, -C 2 F 4 (-), -CH 2 CF 2 (-), -CF 2 CH 2represents -, -CF=CF-, -CH=CF-, -CF=CH-, -CH=CH-, -C≡C- or a single bond, L 1 and L 2 each independently represents F, Cl, CH 3 , CF 3 or CHF 2 and p is 0, 1 or 2, q represents 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10.

[0098] Among the compounds of formula ST, particularly preferred are the compounds represented by formula ST-1 and ST-3, and in particular any of the following: [Chemical formula] [Chemical formula]

[0099] A highly particularly preferred mixture according to the invention comprises one or more stabilizers from the group of compounds represented by formulae ST-1a, ST-1b-1 and ST-1c-1: [Chemical formula] [Chemical formula]

[0100] The compounds represented by formulae ST-1 to ST-12 are preferably present in the liquid crystal mixture according to the invention in an amount of 0.1 to 0.5% each, based on the mixture. However, the total proportion of the compounds represented by formulae ST-1 to ST-12, based on the mixture according to the invention, should not exceed 2%. The medium according to the invention preferably has negative dielectric anisotropy.

[0101] Definition As used herein, the term "reliability" means the quality of the performance of a display over time and under various stress loads such as light load, temperature, humidity, voltage, etc., and includes display effects such as image sticking (area and line image sticking), mura, and stain, which are known to those skilled in the field of LC displays. As a standard parameter for classifying reliability, a voltage holding ratio (VHR) value is usually used, which is a measure for maintaining a constant voltage in a test display. Among other factors, a high VHR is a prerequisite for high reliability of the LC medium.

[0102] As used herein, the terms "active layer" and "switching layer" mean a layer in an electro-optical display, such as an LC display, that contains one or more molecules having structural and optical anisotropy, such as LC molecules, whose orientation is changed by an external stimulus such as an electric or magnetic field, resulting in a change in the transmittance of the layer with respect to polarized or non-polarized light.

[0103] Unless otherwise indicated, the term "LC display" is used herein to refer to an information display based on switchable liquid crystals. This includes backlit and reflective displays for direct or indirect viewing, for virtual reality or augmented reality systems, or for projection systems. The sizes range from microdisplays to large screens. Addressing can be achieved by the LC display including simple electrodes on a substrate, an array of thin film transistors with electrodes for each pixel, or a structured silicon semiconductor as a backplane, with the latter being preferred.

[0104] As used herein, the terms "optically active" and "chiral" are synonyms for materials that can induce a helical pitch in a nematic host material, and are also referred to as "chiral dopants". Throughout the patent application, 1,4-cyclohexylene rings and 1,4-phenylene rings are depicted as follows:

Chemical formula

[0105] The cyclohexylene ring is a trans-1,4-cyclohexylene ring. In the above and below,

Chem.

[0106] group

Chem.

[0107] "Carbon group" represents a monovalent or polyvalent organic group containing at least one carbon atom, which contains no further atoms (e.g., -C≡C-, etc.) or optionally contains one or more further atoms, such as N, O, S, B, P, Si, Se, As, Te, or Ge (e.g., carbonyl, etc.). The term "hydrocarbon group" represents a carbon group that additionally contains one or more H atoms and optionally one or more heteroatoms, such as N, O, S, B, P, Si, Se, As, Te, or Ge.

[0108] "Halogen" represents F, Cl, Br, or I, preferably F or Cl. -CO-, -C(=O)-, and -C(O)- are carbonyl groups, i.e.,

Chem.

[0109] Terms such as "alkyl", "aryl", "heteroaryl", etc. also encompass polyvalent groups such as alkylene, arylene, heteroarylene, etc. The term "aryl" represents an aromatic carbon-based group or a group derived therefrom. The term "heteroaryl" preferably means "aryl" as defined above, including one or more heteroatoms selected from N, O, S, Se, Te, Si, and Ge.

[0110] In the present specification, alkyl is linear or branched and has 1 to 15 C atoms, preferably linear, and, unless otherwise indicated, has 1, 2, 3, 4, 5, 6, or 7 C atoms, and thus is preferably methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, or n-heptyl. In the present specification, branched alkyl is alkyl having secondary and / or tertiary, preferably secondary carbon atoms, and is preferably isopropyl, s-butyl, isobutyl, isopentyl, 2-methylhexyl, or 2-ethylhexyl, 2-methylpropyl, 2-pentyl, 3-pentyl, 2-methylbutyl, 3-methylbutyl.

[0111] As used herein, a cyclic alkyl group is a cyclic aliphatic radical or alkyl group, which may be saturated or partially unsaturated, and is understood to mean one in which a methylene group is replaced by a cyclic aliphatic group (i.e., cyclopropylalkyl or alkylcyclopropylalkyl), and preferably represents cyclopropyl, methylcyclopropyl, cyclobutyl, methylcyclobutyl, cyclopentyl, methylcyclopentyl, cyclopenta-1-enyl, cyclopropylmethyl, cyclopropylethyl, cyclobutylmethyl, cyclobutylethyl, cyclopentylmethyl, cyclopentylethyl, cyclopenta-1-enylmethyl.

[0112] As used herein, an alkoxy radical is straight-chain or branched and contains 1 to 15 carbon atoms. It is preferably straight-chain and, unless otherwise indicated, has 1, 2, 3, 4, 5, 6 or 7 carbon atoms and is thus preferably methoxy, ethoxy, n-propoxy, n-butoxy, n-pentoxy, n-hexoxy or n-heptoxy.

[0113] As used herein, an alkenyl radical is preferably an alkenyl radical having 2 to 15 carbon atoms, which is straight-chain or branched and contains at least one C-C double bond. It is preferably straight-chain and has 2 to 7 carbon atoms. Thus, it is preferably vinyl, prop-1- or -2-enyl, but-1-, -2- or -3-enyl, pent-1-, -2-, -3- or -4-enyl, hex-1-, -2-, -3-, -4- or -5-enyl, hept-1-, -2-, -3-, 4-, -5- or -6-enyl. When the two carbon atoms of the C-C double bond are substituted, the alkenyl radical can be in the form of E and / or Z isomers (trans / cis). Generally, each E isomer is preferred. Among the alkenyl radicals, prop-2-enyl, but-2- and -3-enyl, and pent-3- and -4-enyl are particularly preferred.

[0114] As used herein, alkynyl is understood to mean an alkynyl radical that is linear or branched and has 2 to 15 carbon atoms including at least one C-C triple bond. 1- and 2-propynyl, and 1-, 2- and 3-butynyl are preferred.

[0115] Preferred carbon and hydrocarbon groups are optionally substituted linear, branched or cyclic alkyl, alkenyl, alkynyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy and alkoxycarbonyloxy having 1 to 40, preferably 1 to 20, very preferably 1 to 12 carbon atoms, optionally substituted aryl or aryloxy having 5 to 30, preferably 6 to 25 carbon atoms, or optionally substituted alkylaryl, arylalkyl, alkylaryloxy, arylalkyloxy, arylcarbonyl, aryloxycarbonyl, arylcarbonyloxy and aryloxycarbonyloxy having 5 to 30, preferably 6 to 25 carbon atoms, where one or more of the carbon atoms may also be optionally replaced by one or more heteroatoms selected preferably from N, O, S, Se, Te, Si and Ge.

[0116] Even more preferred carbon and hydrocarbon groups are C 1 ~C 20 alkyl, C 2 ~C 20 alkenyl, C 2 ~C 20 alkynyl, C 3 ~C 20 allyl, C 4 ~C 20 alkyldienyl, C 4 ~C 20 polyenyl, C 6 ~C 20 cycloalkyl, C 4 ~C 15 cycloalkenyl, C 6 ~C 30 aryl, C 6 ~C 30 alkylaryl, C 6 ~C30 Arylalkyl, C 6 ~C 30 Alkylaryloxy, C 6 ~C 30 Arylalkyloxy, C 2 ~C 30 Heteroaryl, C 2 ~C 30 is heteroaryloxy. Particularly preferred are C 1 ~C 12 Alkyl, C 2 ~C 12 Alkenyl, C 2 ~C 12 Alkynyl, C 6 ~C 25 Aryl and C 2 ~C 25 is heteroaryl.

[0117] Even more preferred carbon and hydrocarbon groups are straight-chain, branched or cyclic alkyls having 1 to 20, preferably 1 to 12 C atoms, which are unsubstituted or mono- or polysubstituted by F, Cl, Br, I or CN, and where one or more non-adjacent CH 2 groups, independently of one another, are each replaced in such a way that O and / or S atoms are not directly linked to each other by -C(R x )=C(R x )-, -C≡-, -N(R x )-, -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O-.

[0118] R xrepresents, preferably, H, F, Cl, CN, a linear, branched or cyclic alkyl chain having 1 to 25 C atoms, where, in addition, one or more non-adjacent C atoms may be replaced by -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O-, and where one or more H atoms may be replaced by F or Cl, or an optionally substituted aryl or aryloxy group having 6 to 30 C atoms, or an optionally substituted heteroaryl or heteroaryloxy group having 2 to 30 C atoms.

[0119] Preferred alkyl groups are, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, s-butyl, t-butyl, 2-methylbutyl, n-pentyl, s-pentyl, cyclopentyl, n-hexyl, cyclohexyl, 2-ethylhexyl, n-heptyl, cycloheptyl, n-octyl, cyclooctyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, dodecanyl, trifluoromethyl, perfluoro-n-butyl, 2,2,2-trifluoroethyl, perfluorooctyl, perfluorohexyl, etc. Preferred alkenyl groups are, for example, ethenyl, propenyl, butenyl, pentenyl, cyclopentenyl, hexenyl, cyclohexenyl, heptenyl, cycloheptenyl, octenyl, cyclooctenyl, etc. Preferred alkynyl groups are, for example, ethynyl, propynyl, butynyl, pentynyl, hexynyl, octynyl, etc.

[0120] Preferred alkoxy groups are, for example, methoxy, ethoxy, 2-methoxyethoxy, n-propoxy, i-propoxy, n-butoxy, i-butoxy, s-butoxy, t-butoxy, 2-methylbutoxy, n-pentoxy, n-hexoxy, n-heptoxy, n-octoxy, n-nonoxy, n-decoxy, n-undecoxy, n-dodecoxy, etc. Preferred amino groups are, for example, dimethylamino, methylamino, methylphenylamino, phenylamino, etc.

[0121] Aryl groups and heteroaryl groups can be monocyclic or polycyclic, i.e., they can contain one ring (e.g., phenyl, etc.) or two or more rings, which can also be fused (e.g., naphthyl, etc.) or covalently bonded (e.g., biphenyl, etc.), or can include a combination of fused rings and linked rings. The heteroaryl group preferably contains one or more heteroatoms selected from O, N, S, and Se.

[0122] Particularly preferred are monocyclic, bicyclic or tricyclic aryl groups having 6 to 25 C atoms, and monocyclic, bicyclic or tricyclic heteroaryl groups having 5 to 25 ring atoms, which optionally contain fused rings and may be optionally substituted. Also preferred are 5-membered, 6-membered or 7-membered aryl groups and heteroaryl groups, where in addition, one or more CH groups may be replaced by N, S or O in such a way that O atoms and / or S atoms are not directly linked to each other.

[0123] Preferred aryl groups are, for example, phenyl, biphenyl, terphenyl, [1,1’:3’,1”]-terphenyl-2’-yl, naphthyl, anthracene, binaphthyl, phenanthrene, pyrene, dihydropyrene, chrysene, perylene, tetracene, pentacene, benzopyrene, fluorene, indene, indenofluorene, spirobifluorene, etc.

[0124] Preferred heteroaryl groups include, for example, 5-membered rings such as pyrrole, pyrazole, imidazole, 1,2,3-triazole, 1,2,4-triazole, tetrazole, furan, thiophene, selenophene, oxazole, isoxazole, 1,2-thiazole, 1,3-thiazole, 1,2,3-oxadiazole, 1,2,4-oxadiazole, 1,2,5-oxadiazole, 1,3,4-oxadiazole, 1,2,3-thiadiazole, 1,2,4-thiadiazole, 1,2,5-thiadiazole, 1,3,4-thiadiazole, 6-membered rings such as pyridine, pyridazine, pyrimidine, pyrazine, 1,3,5-triazine, 1,2,4-triazine, 1,2,3-triazine, 1,2,4,5-tetrazine, 1,2,3,4-tetrazine, 1,2,3,5-tetrazine, or fused groups such as indole, isoindole, indolizine, indazole, benzimidazole, benzotriazole, purine, naphthylimidazole, phenanthrylimidazole, pyridoimidazole, pyrazinoimidazole, quinoxalineimidazole, benzoxazole, naphthoxazole, anthraoxazole, phenanthryloxazole, isoxazole, benzothiazole, benzofuran, isobenzofuran, dibenzofuran, quinoline, isoquinoline, pteridine, benzo-5,6-quinoline, benzo-6,7-quinoline, benzo-7,8-quinoline, benzoisoquinoline, acridine, phenothiazine, phenoxazine, benzopyridazine, benzopyrimidine, quinoxaline, phenazine, naphthyridine, azacarbazole, benzocarbazole, phenanthridine, phenanthroline, thieno[2,3b]thiophene, thieno[3,2b]thiophene, dithienothiophene, isobenzothiophene, dibenzothiophene, benzothiadiazothiophene, or combinations of these groups.

[0125] The aryl and heteroaryl groups mentioned above and below may also be substituted by alkyl, alkoxy, thioalkyl, fluorine, fluoroalkyl, or a further aryl or heteroaryl group. (Non-aromatic) alicyclic and heterocyclic groups encompass both saturated rings, i.e., rings containing only single bonds, and also partially unsaturated rings, i.e., rings that may contain multiple bonds. Heterocycles preferably contain one or more heteroatoms selected from O, N, S, and Se.

[0126] (Non-aromatic) alicyclic and heterocyclic groups can be monocyclic, i.e., containing only one ring (e.g., cyclohexane, etc.), or polycyclic, i.e., containing multiple rings (e.g., decahydronaphthalene or bicyclooctane, etc.). Particularly preferred are saturated groups. Further preferred are monocyclic, bicyclic, or tricyclic groups having 5 to 25 C atoms, which may optionally contain fused rings and may be optionally substituted. Even more preferred are 5-membered, 6-membered, 7-membered, or 8-membered carbocyclic groups, where, in addition, one or more C atoms may be replaced by Si, and / or one or more CH groups may be replaced by N, and / or one or more non-adjacent CH 2 groups may be replaced by -O- and / or -S-.

[0127] Preferred alicyclic and heterocyclic groups are, for example, 5-membered groups such as cyclopentane, tetrahydrofuran, tetrahydrothiophene, pyrrolidine, etc., 6-membered groups such as cyclohexane, silinane, cyclohexene, tetrahydropyran, tetrahydrothiopyran, 1,3-dioxane, 1,3-dithiane, piperidine, etc., 7-membered groups such as cycloheptane, etc., and fused groups such as tetrahydronaphthalene, decahydronaphthalene, indane, bicyclo[1.1.1]pentane-1,3-diyl, bicyclo[2.2.2]octane-1,4-diyl, spiro[3.3]heptane-2,6-diyl, octahydro-4,7-methanoindane-2,5-diyl, etc.

[0128] Preferred substituents are, for example, dissolution promoting groups such as alkyl or alkoxy, electron withdrawing groups such as fluorine, nitro or nitrile, or substituents for raising the polymerizable glass transition temperature (Tg), in particular bulky groups such as, for example, t-butyl group or an optionally substituted aryl group.

[0129] Preferred substituents (hereinafter also referred to as "L") are, for example, F, Cl, Br, I, -CN, -NO 2 , -NCO, -NCS, -OCN, -SCN, -C(=O)N(R x ) 2 , -C(=O)Y 1 , -C(=O)R x , -N(R x ) 2 , linear or branched alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy each having 1 to 25 C atoms, where one or more H atoms may optionally be replaced by F or Cl, optionally substituted silyl having 1 to 20 Si atoms, or optionally substituted aryl having 6 to 25, preferably 6 to 15 C atoms, wherein R x represents H, F, Cl, CN, or linear, branched or cyclic alkyl having 1 to 25 C atoms, where one or more non-adjacent CH 2 groups are optionally replaced by -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O- in such a way that O- and / or S-atoms are not directly linked to each other, and where one or more H atoms are each optionally replaced by F, Cl, P- or P-Sp-, and Y 1 represents halogen.

[0130] "Substituted silyl or aryl" is preferably halogen, -CN, R 0 , -OR 0 , -CO-R 0 , -CO-OR 0 , -O-CO-R 0or -O-CO-OR 0 which means being substituted with, where R 0 represents H or an alkyl containing 1 to 20 C atoms. Particularly preferred substituents L are, for example, F, Cl, CN, NO 2 , CH 3 , C 2 H 5 , OCH 3 , OC 2 H 5 , COCH 3 , COC 2 H 5 , COOCH 3 , COOC 2 H 5 , CF 3 , OCHF 3 , OC 2 F 5 and furthermore phenyl.

[0131] The LC medium according to the invention may in addition contain one or more further constituents or additives, preferably selected from the list including but not limited to comonomers, polymerization initiators, inhibitors, stabilizers, surfactants, wetting agents, lubricants, dispersants, hydrophobizing agents, adhesives, fluidity improvers, defoamers, degassing agents, diluents, reactive diluents, auxiliaries, colorants, dyes, pigments and nanoparticles. The LC medium according to the invention may contain one, two or three chiral dopants, preferably one chiral dopant.

[0132] Preferred embodiments, employed alone or in combination with each other, are listed below. The medium according to the invention preferably contains the following: - a compound represented by formula I at a concentration in the range of 2% to 20%, preferably 3% to 16%, and most preferably 3% to 14%; - a compound represented by formula IV-2 at a concentration in the range of 4% to 20%, preferably 5% to 15%, and most preferably 6% to 12%; - A compound represented by formula ST-1 in a concentration range of 0.11% to 0.85%, preferably 0.15% to 0.40%, most preferably 0.16% to 0.30%, or other combinations of these boundaries; - A compound represented by formula H, preferably by formula HA, more preferably by formula H-1, in a concentration range of 0.008% to 0.08%, preferably 0.012% to 0.06%, most preferably 0.015% to 0.04%; - One or more compounds represented by formulae IIA, IIB, IIC, IID, IIE and III in a total concentration range of 68% to 88%, more preferably 70% to 85%, and most preferably 71% to 83%; - One, two, three or more compounds represented by formula III, preferably by formula III-1 and / or III-2, more preferably by formula III-2, in a total concentration range of 0% to 15%, more preferably 1% to 12%, most preferably 2% to 10%, particularly 3% to 8%; - One or more compounds represented by formula IIA in a total concentration range of 15% to 50%, more preferably 15% to 45%, and most preferably 35% to 43% or 20% to 25%; - One or more compounds represented by formula IIA-2 in a total concentration range of 3% to 18%, more preferably 5% to 16%, and most preferably 5% to 16%; - One or more compounds represented by formula IIA-10 in a total concentration range of 10% to 32%, more preferably 12% to 30%, and most preferably 13% to 29%; - One or more compounds selected from compounds represented by formula IIC, more preferably by IIC-1 and IIC-2, preferably by formula IIC-1, in a total concentration range of 1% to 25%, more preferably 4% to 25%, and most preferably 8% to 22%; - One or more compounds represented by formula IIE, more preferably by formula IIE-1, in a total concentration range of 1% to 18%, more preferably 2% to 15%, and most preferably 3% to 12%; - One or more compounds represented by Formula IIB, preferably represented by Formula IIB-2 and / or IIB-10, in a total concentration in the range of 7% to 30%, more preferably 8% to 27%, and most preferably 9% to 26%; - One or more compounds represented by Formula IIB-2 in a total concentration in the range of 7% to 30%, more preferably 8% to 27%, most preferably 9% to 26%; - One or more compounds represented by Formula IIA and one or more compounds represented by Formula IIB, preferably selected from Formula IIA-2, IIA-10, IIB-2 and IIB-10, in a total concentration in the range of preferably 44% to 70%, more preferably 45% to 68%, and most preferably 40% to 67%; - One or more compounds represented by Formula IV-1, preferably Compound IV-1-3, in a total concentration in the range of 1% to 15%, more preferably 2% to 12%, and most preferably 5% to 12%; - One or more compounds represented by Formula IV-3, preferably represented by Formula IV-3-2 and / or IV-3-5, in a total concentration in the range of 1% to 25%, more preferably 2% to 20%, and most preferably 3% to 16%; - Two or more compounds represented by Formula I and Formula IV in a total concentration in the range of 18% to 30%, more preferably 19% to 25%, and most preferably 20% to 24%; - Two or more of a compound represented by Formula I, a compound represented by Formula IV, and a compound represented by Formula V in a total concentration in the range of 20% to 30%, more preferably 20% to 28%, most preferably 20% to 27%, especially 21% to 27%.

[0133] Particularly preferred mixing concepts are shown below: (The acronyms used are explained in Tables A - D. Here, n and m each independently represent 1 - 6.) The mixture according to the invention preferably comprises the following: - PYP-n-m, especially PYP-2-3 and / or PYP-2-4, in a concentration of >5%, especially 8 - 30%, preferably based on the total mixture; and / or - Preferably at a concentration of >5%, especially 10 - 30%, based on the total mixture, of CPY-n-Om, especially CPY-2-O2, CPY-3-O2 and / or CPY-5-O2, and / or - Preferably at a concentration of 1 - 15% of B-nO-Om and / or B(S)-nO-Om, and / or - Preferably at a concentration of >5%, especially 15 - 50%, based on the total mixture, of CY-n-Om, preferably CY-3-O2, CY-3-O4, CY-5-O2 and / or CY-5-O4, and / or - Preferably at a concentration of >5%, especially 10 - 30%, based on the total mixture, of CCY-n-Om, preferably CCY-4-O2, CCY-3-O2, CCY-3-O3, CCY-3-O1 and / or CCY-5-O2, and / or - Preferably at a concentration of >5%, especially 10 - 30%, based on the total mixture, of CLY-n-Om, preferably CLY-2-O4, CLY-3-O2 and / or CLY-3-O3, and / or - Preferably at a concentration of >5%, especially 10 - 30%, based on the total mixture, of LY-n-Om, preferably LY-3-O2, and / or - Preferably at a concentration of >5%, especially 10 - 30%, based on the total mixture, of CCOY-n-Om, preferably CCOY-3-O2, and / or - Preferably at a concentration of >5%, especially 10 - 30%, based on the total mixture, of CLOY-n-Om, preferably CLOY-3-O2.

[0134] The LC medium according to the invention preferably advantageously has a nematic phase of ≦ -20°C to ≧ 90°C, particularly preferably ≦ -30°C to ≧ 100°C, and extremely particularly preferably ≦ -40°C to ≧ 105°C. In a preferred embodiment, the medium according to the invention has a clearing temperature (clearing point) of 90 °C or higher, more preferably 100 °C or higher, in particular 105 °C or higher.

[0135] As used herein, the expression "having a nematic phase" at a given temperature means that neither a smectic phase nor crystallization is observed at low temperatures and, on the other hand, no clearing (phase transition to an isotropic phase) occurs when the nematic phase is heated at the given temperature. The investigation at low temperatures is carried out with a flow viscometer at the corresponding temperature and checked by storage in a test cell having a layer thickness corresponding to at least 100 hours of electro-optical use. If the storage stability at a temperature of -20 °C in the corresponding test cell is 1000 hours or more, the medium is considered to be stable at this temperature. At temperatures of -30 °C and -40 °C, the corresponding times are 500 hours and 250 hours respectively. At high temperatures, the clearing point is measured in a capillary by conventional methods.

[0136] The liquid crystal mixture preferably has a nematic phase range of at least 60 K and a kinematic viscosity ν of at most 30 mm 2 ·s -1 at 20 °C. 20 The mixture is nematic at temperatures of -20 °C or lower, preferably -30 °C or lower, and most preferably -40 °C or lower.

[0137] The medium according to the invention has a birefringence in the range from 0.085 to 0.170, preferably from 0.13 to 0.16, in particular from 0.14 to 0.16. In a preferred embodiment, the medium has a birefringence in the range from 0.1480 to 0.155, preferably from 0.147 to 0.153, in particular from 0.158 to 0.152.

[0138] In a preferred embodiment, the medium according to the invention has a dielectric anisotropy Δε in the range from -2.5 to -6.0, preferably from -2.8 to -4.7, in particular from -3.5 to -4.5. In a very preferred embodiment, the liquid crystal mixture according to the invention has a dielectric anisotropy Δε in the range from -3.8 to -4.2.

[0139] Rotational viscosity at 20 °C γ1 is preferably in the range of 90 to 300 mPa·s, more preferably in the range of 100 to 290 mPa·s. The medium according to the present invention has an elastic constant in the range of 16 to 20 pN K1 and has. In a preferred embodiment, the medium according to the present invention has a ratio γ of the rotational viscosity to the spray elastic constant 1 / K 1 of 15 mPa·s·pN -1 or less.

[0140] The liquid crystal medium according to the present invention has a relatively low threshold voltage (V 0 ). They are preferably in the range of 1.7 V to 3.0 V, particularly preferably ≦ 2.6 V, and extremely particularly preferably ≦ 2.4 V. For the present invention, the term "threshold voltage" refers to the capacitance threshold voltage (V 0 ) also called the Frederiks threshold, unless explicitly stated otherwise.

[0141] In addition, the liquid crystal medium according to the present invention has a high value of the voltage holding ratio in the liquid crystal cell. Generally, a liquid crystal medium having a low address voltage or threshold voltage exhibits a lower voltage holding ratio than one having a higher address voltage or threshold voltage, and vice versa.

[0142] For the present invention, the term "dielectrically positive compound" represents a compound having Δε > 1.5, the term "dielectrically neutral compound" represents those having -1.5 ≤ Δε ≤ 1.5, and the term "dielectrically negative compound" represents those having Δε < -1.5. The dielectric anisotropy of a compound is determined here by dissolving 10% of the compound in a liquid crystal host and determining the capacitance of the resulting mixture at 1 kHz in at least one test cell having a layer thickness of 20 μm with a homeotropic and uniform surface orientation for each case. The measurement voltage is typically 0.5 V to 1.0 V, but always lower than the capacitive threshold of each liquid crystal mixture investigated.

[0143] All temperature values shown for the present invention are in °C. Mixtures according to the present invention are suitable for all VA-TFT applications such as, for example, VAN, MVA, (S)-PVA, ASV, PSA (polymer sustained VA), PS-VA (polymer stabilized VA), etc. These are also further suitable for IPS (In-Plane Switching, i n- p lane s witching) and FFS (Fringe Field Switching, f ringe f ield s witching) applications.

[0144] This mixture is also particularly suitable for LCoS type VA-TFT applications, more preferably for LCoS microdisplays. An LCoS microdisplay is a reflective display typically including a liquid crystal layer having a nematic structure between a silicon backplane and a cover glass. The silicon backplane is an array of pixels, each pixel having a mirror surface, which also function as electrical conductors simultaneously. Each pixel includes a fixed mirror covered with an active liquid crystal layer having a twisted nematic orientation that can be switched between a homeotropic orientation and a homogeneous orientation by applying a voltage. Although LCoS microdisplays are small, typically having a diagonal of less than 1.0", they can still achieve high resolution.

[0145] Due to the small pixel size, the cell thickness in LCoS displays is also extremely small, typically about 1 micron. Therefore, the liquid crystal phase used in these displays must have a particularly high value of optical anisotropy Δn, in contrast to conventional reflective LC displays that usually require an LC phase with a low Δn.

[0146] In a preferred embodiment, the LCoS panel according to the present invention includes an inorganic alignment layer, more preferably a vertical alignment layer for vertical alignment of the liquid crystal medium. Most preferably, it is a SiO x alignment layer. Such an inorganic alignment layer is particularly well-suited for LCoS panels.

[0147] As is well understood by those skilled in the art, the VA, IPS or FFS mixtures according to the present invention may also include, for example, compounds in which H, N, O, Cl and F are replaced by the corresponding isotopes.

[0148] The compounds according to the invention can be synthesized by known methods described in the literature (for example, in standard works such as Houben-Weyl, Methoden der Organischen Chemie [Methods of Organic Chemistry], Georg-Thieme-Verlag, Stuttgart) or by methods analogous thereto, under known and suitable reaction conditions for the reaction. Here, modifications that are known per se but not mentioned herein can also be used. In particular, they can be prepared as described in the following reaction schemes or by methods analogous thereto. Further methods for preparing the compounds of the invention can be adopted from the examples.

[0149] Other mesogenic compounds not explicitly mentioned above can also optionally and advantageously be used in the media according to the invention. Such compounds are known to the person skilled in the art.

[0150] For the present invention and in the following examples, the structures of the liquid crystal compounds are indicated using acronyms, and the conversion to chemical formulas is carried out according to Tables A - C below. All radicals C m H 2m+1 、C n H 2n+1 、and C l H 2l+1 or C m H 2m-1 、C n H 2n-1 、and C l H 2l-1 are, respectively, straight-chain alkyl radicals or alkylene radicals, having n, m, and l carbon atoms each time. Preferably, n, m, and l are, independently of one another, 1, 2, 3, 4, 5, 6, or 7.

[0151] Table A shows the codes for the ring elements of the nucleus of the compounds, Table B lists the crosslinking units, and Table C lists the meanings of the symbols related to the left and right end groups of the molecule. The acronym consists of the code related to the ring element with any linking group, followed by the first hyphen and the code related to the left end group, and the second hyphen and the code related to the right end group. Table D shows the exemplary structures of the compounds together with their respective abbreviations.

[0152] Table A: Ring Element

Table A-1

Table A-2

Table A-3

[0153] Table B: Crosslinking Unit

Table B

[0154] Table C: Terminal Group

Table C-1

Table C-2

[0155] Apart from the compounds represented by Formulae IV-2, I and ST-1, the mixtures according to the invention optionally contain one or more compounds from those listed in Table D. The following abbreviations are used: (n, m, k, and l are each, independently of one another, integers, preferably from 1 to 9, preferably from 1 to 7, and k and l may also, according to circumstances, be 0, preferably from 0 to 4, more preferably 0 or 2, most preferably 2, and n is preferably 1, 2, 3, 4, or 5, and in the combination "-nO-", it is preferably 1, 2, 3, or 4, preferably 2 or 4, and m is preferably 1, 2, 3, 4, or 5, and in the combination "-Om", it is preferably 1, 2, 3, or 4, preferably 2 or 4. The combination "-lVm" is preferably "2V1".)

[0156] Table D The following exemplary structures are examples and are also preferably compounds used additionally in the medium. [Table D-1] [Table D-2] [Table D-3] [Table D-4] [Table D-5] [Table D-6] [Table D-7] [Table D-8] [Table D-9] [Table D-10] [Table D-11]

Table D-12

Table D-13

Table D-14

Table D-15

Table D-16

[0157] Table E shows the chiral dopants preferably employed in the mixtures according to the invention. Table E

Table E-1

Table E-2

[0158] In a preferred embodiment of the invention, the medium according to the invention comprises one or more compounds selected from the group of compounds from Table E.

[0159] Example The invention is illustrated in detail by the following non-limiting examples. The following abbreviations and symbols are used: V 0 Threshold voltage, capacitance at 20 °C [V], n e Anomalous refractive index at 20 °C and 589 nm, n o Normal refractive index at 20 °C and 589 nm, Δn Optical anisotropy at 20 °C and 589 nm, ε⊥ Dielectric constant perpendicular to the director at 20 °C and 1 kHz, ε|| Dielectric constant parallel to the director at 20 °C and 1 kHz, Δε Dielectric anisotropy at 20 °C and 1 kHz, cl.p., T(N,I) clearing point [°C], γ 1 Rotational viscosity at 20 °C [mPa·s], K 1 Elastic constant, "spray" deformation at 20 °C [pN], K 2 Elastic constant, "twist" deformation at 20 °C [pN], K 3 Elastic constant, "bend" deformation at 20 °C [pN].

[0160] Unless explicitly stated otherwise, all concentrations in this application are expressed in weight percent and relate to the entire corresponding mixture containing all solid or liquid crystalline components without solvent. Unless explicitly stated otherwise, all temperature values shown in this application, for example, melting point T(C, N), transition from the smectic phase (S, Sm) to the nematic phase (N) T(S / Sm, N), and clearing point T(N, I), etc., are shown in degrees Celsius (°C). M.p. represents the melting point and cl.p. = clearing point. Furthermore, C = crystalline state, N = nematic phase, S = smectic phase, I = isotropic phase. The data between these symbols represent transition temperatures.

[0161] Unless explicitly stated otherwise for each case, all physical properties are determined according to "Merck Liquid Crystals, Physical Properties of Liquid Crystals" (published in November 1997, Merck KGaA, Germany) and applied at a temperature of 20 °C, Δn is at 589 nm, and Δε is determined at 1 kHz. The term "threshold voltage" for the present invention refers to the capacitance threshold (V 0 ), also known as the Freedericks threshold, unless explicitly shown otherwise. In the examples, the optical threshold is, as usual, at 10% relative contrast (V10 ) may also be shown for

[0162] Unless otherwise stated, the method of preparing test cells and measuring their electro-optical and other properties is carried out by the methods described hereinafter or methods similar thereto. The display used for measuring the capacitance threshold voltage consists of two plane-parallel glass outer plates spaced 25 μm apart, each of which has an electrode layer on the inside and, thereon, an unrubbed polyimide alignment layer that provides a homeotropic alignment of liquid crystal molecules.

[0163] Unless otherwise shown, VHR is a commercially available device model LCM-1 (O0004) from TOYO Corporation, Japan, at 20 °C (VHR 20 ) and after 5 minutes in an oven at 100 °C (VHR 100 ) is determined. Unless more precisely shown, the voltage used has a frequency within the range of 1 Hz to 60 Hz.

[0164] The stability against UV irradiation is investigated using a xenon lamp NXE1500B in a commercially available device "Suntest CPS+" from Heraeus, Germany. The sealed test cells are irradiated for 2.0 hours without additional heating unless explicitly shown. The irradiation power in the wavelength range of 300 nm to 800 nm is 765 W / m 2 V. To simulate the so-called window glass mode, a UV "cut-off" filter with an edge wavelength of 310 nm is used. In each series of experiments, at least 4 test cells are investigated for each condition, and each result is shown as the average of the corresponding individual measured values.

[0165] To investigate the low temperature stability (also known as "LTS"), i.e., the stability of the LC mixture in the bulk against the spontaneous crystallization of the individual components at low temperatures or, in some cases, the occurrence of the smectic phase, several sealed bottles each containing approximately 1 g of the material are stored at one or more given temperatures, typically -10°C, -20°C, -30°C, and / or -40°C, and are visually inspected periodically to see if a phase transition is observed. As soon as a change is seen in the first sample at a given temperature, the time is noted. The time until the last inspection where no change was observed is noted as the respective LTS.

[0166] The ion density for calculating the resistivity is measured using a VHR test cell with AL16301 polyimide (JSR Corp., Japan) having a cell gap of 3.2 μm, using a commercially available LC Material Characteristics Measurement System Model 6254 from Toyo Corporation, Japan. The measurement is performed after storing in an oven at 60°C or 100°C for 5 minutes.

[0167] The clearing point is measured using a Mettler Thermosystem FP900. The optical anisotropy (Δn) is measured using an Abbe refractometer H005 (sodium spectrum lamp Na10, 589 nm, at 20°C). The dielectric anisotropy (Δε) is measured using an LCR-Meter E4980A / Agilent (G005) at 20°C (ε-parallel cell equipped with JALS 2096-R1). The threshold voltage (V 0 ) is measured using an LCR-Meter E4980A / Agilent (G005) at 20°C (ε-parallel cell equipped with JALS 2096-R1). The rotational viscosity (γ 1 ) is measured using a TOYO LCM-2 (0002) at 20°C (gamma 1 negative cell equipped with JALS 2096-R1). The elastic constant (K 1, spray) is measured at 20 °C (ε-parallel cell equipped with JALS 2096-R1) using an LCR-Meter E4980A / Agilent (G005). K 3 : Elastic constant (K 3 , bending) is measured at 20 °C (ε-parallel cell equipped with JALS 2096-R1) using an LCR-Meter E4980A / Agilent (G005).

[0168] The following mixture examples having negative dielectric anisotropy are particularly suitable for vertical alignment liquid crystal displays. Mixture Example The following stabilizing compounds are used and described by the following acronyms:

Chemical formula

Chemical formula

[0169] The nematic LC mixtures M1 to M41 have the compositions and physical properties shown in the following table: Host Mixture M1

Table 1

[0170] Exemplary Mixture M2

Table 2

[0171] Exemplary Mixture M3

Table 3

[0172] Host Mixture M4

Table 4

[0173] Exemplary Mixture M5

Table 5

[0174] Host Mixture M6

Table 6

[0175] Exemplary Mixture M7

Table 7

[0176] Host Mixture M8

Table 8

[0177] Exemplary Mixture M9

Table 9

[0178] Host Mixture M10

Table 10

[0179] Exemplary Mixture M11

Table 11

[0180] Host Mixture M12

Table 12

[0181] Exemplary Mixture M13

Table 13

[0182] Exemplary Mixture M14

Table 14

[0183] Host Mixture M15

Table 15

[0184] Exemplary Mixture M16

Table 16

[0185] Host Mixture M17

Table 17

[0186] Exemplary Mixture M18

Table 18

[0187] Host Mixture M19

Table 19

[0188] Exemplary Mixture M20

Table 20

[0189] Host Mixture M21

Table 21

[0190] Exemplary Mixture M22

Table 22

[0191] Exemplary Mixture M23

Table 23

[0192] Host Mixture M24

Table 24

[0193] Exemplary Mixture M25

Table 25

[0194] Host Mixture M26

Table 26

[0195] Exemplary Mixture M27

Table 27

[0196] Host Mixture M28

Table 28

[0197] Exemplary Mixture M29

Table 29

[0198] Exemplary Mixture M30

Table 30

[0199] Host Mixture M31

Table 31

[0200] Exemplary Mixture M32

Table 32

[0201] Exemplary Mixture M33

Table 33

[0202] Host Mixture M34

Table 34

[0203] Exemplary Mixture M35

Table 35

[0204] Host Mixture M36

Table 36

[0205] Exemplary Mixture M37

Table 37

[0206] Host Mixture M38

Table 38

[0207] Exemplary Mixture M39

Table 39

[0208] Exemplary Mixture M40

Table 40

[0209] Exemplary Mixture M41

Table 41

[0210] Exemplary Mixture M42

Table 42

[0211] Stability Test The above exemplary mixture is provided to a test cell with an inorganic alignment (SiO x ) layer or a similar LCoS panel. The device is tested under forced temperature and illumination (stress test blue light, >45W / cm 2 , 70 °C). The generation of bubbles and blackening is avoided over the long term. Under these conditions, it can be seen that the alignment of the mixture is stable over the long term. The stability for practical use in LCoS of the mixture is improved compared to conventional mixtures.

Claims

1. A liquid crystal on silicon (LCoS) panel, comprising: a semiconductor substrate having a plurality of reflective electrodes; a transparent substrate having transparent electrodes assembled with the semiconductor substrate; and a liquid crystal layer disposed between the semiconductor substrate and the transparent substrate, The liquid crystal layer is a) one or more compounds of formula IV 【Chemistry 1】 In the formula, R 41 represents an unsubstituted alkyl radical having 1 to 7 C atoms or an unsubstituted alkenyl radical having 2 to 7 C atoms, and R 42 represents an unsubstituted alkyl radical having 1 to 7 C atoms, or an unsubstituted alkoxy radical having 1 to 6 C atoms, or an unsubstituted alkenyl radical having 2 to 7 C atoms, wherein the one or more compounds of formula IV are selected from formula IV-2: 【Chemistry 2】 Where: Alkyl represents alkyl having 1 to 7 C atoms, and Alkoxy represents alkoxy having 1 to 5 C atoms, The LCoS panel comprises a liquid crystal medium comprising:

2. 10. The LCoS panel of claim 1 comprising one or more inorganic alignment layers.

3. 3. An LCoS panel according to claim 1, wherein the liquid crystal medium has a clearing point of 90° C. or higher.

4. 4. The LCoS panel according to claim 1, wherein the liquid crystal medium is aligned perpendicular to the substrate.

5. a) one or more compounds of formula IV 【Chemistry 3】 In the formula, R 41 represents an unsubstituted alkyl radical having 1 to 7 C atoms or an unsubstituted alkenyl radical having 2 to 7 C atoms, and R 42 represents an unsubstituted alkyl radical having 1 to 7 C atoms, an unsubstituted alkoxy radical having 1 to 6 C atoms or an unsubstituted alkenyl radical having 2 to 7 C atoms, wherein the one or more compounds of formula IV are selected from formula IV-2: 【Chemistry 4】 Where: Alkyl represents an alkyl having 1 to 7 C atoms, Alkoxy represents alkoxy having 1 to 5 C atoms, b) one or more compounds of formula I 【Chemistry 5】 In the formula, R 11 represents alkyl having 1 to 7 C atoms, alkoxy having 1 to 7 C atoms, or alkoxyalkyl having 2 to 7 C atoms, alkenyl, or alkenyloxy, where in addition, one or more CH 2 The groups are, independently of one another, 【Chemistry 6】 and R 12は , alkyl having 1 to 7 C atoms, alkoxy having 1 to 7 C atoms, or alkoxyalkyl having 2 to 7 C atoms, alkenyl or alkenyloxy, And, c) 0.1% to 0.9% of one or more compounds of formula ST-1 【Chemistry 7】 During the ceremony R ST represents H, an alkyl or alkoxy radical having 1 to 15 C atoms, where in addition, one or more CH 2 The groups are, independently of one another, -C≡C-, -CF 2 O-, -OCF 2 -, -CH=CH-, 【Chemistry 8】 may each be replaced by -O-, -CO-O- or -O-CO- in such a way that the O atoms are not directly linked to each other, and in which, in addition, one or more H atoms may be replaced by halogen; 【Chemistry 9】 is, at each occurrence, Same or different, 【Chemistry 10】 represents Z ST are each independently -CO-O-, -O-CO-, -CF 2 O-, -OCF 2 -, -CH 2 O-, -OCH 2 -, -CH 2 -, -CH 2 CH 2 -, -(CH 2 ) 4 -, -CH=CH-, -CH 2 O-, -C 2 F 4 -, -CH 2 CF 2 -, -CF 2 CH 2 represents -, -CF=CF-, -CH=CF-, -CF=CH-, -CH=CH-, -C≡C- or a single bond, and p represents 0, 1, or 2 A liquid crystal medium comprising:

6. 6. A liquid-crystalline medium according to claim 5, The groups of formulas in d) and e): d) Formulas IIA, IIB, IIC, IID and IIE 【Chemistry 11】 In the formula, R 2A , R 2B , R 2C , R 2D , R 2E1 and R 2E2 each independently of one another represents H, an alkyl radical having 1 to 7 C atoms, or an alkenyl radical having 2 to 7 C atoms, each of which is unsubstituted or at least monosubstituted by halogen, where in these radicals one or more CH 2 The groups are -O-, -S-, 【Chemistry 12】 -C≡C-, -CF 2 O-, -OCF 2 may be replaced by -, -OC-O- or -O-CO-, respectively, in such a way that the O atoms are not directly linked to each other; L 1 and L 2 are each independently F, Cl, CF 3 or CHF 2 represents; Y is H, F, Cl, or CF 3 , CHF 2 or CH 3 represents; Z 2 , Z 2B and Z 2D are each independently a single bond, -CH 2 CH 2 -, -CF 2 O-, -OCF 2 -, -CH 2 O-, -OCH 2 -, -COO-, -OCO-, p represents 0, 1, or 2; q represents 0 or 1, and v represents 1, 2, 3, 4, 5, or 6; e) Formula III 【Chemistry 13】 In the formula, R 31 and R 32 each independently of one another represents H, an alkyl or alkoxy radical having 1 to 7 C atoms, where in these radicals one or more CH 2 The groups are, independently of one another, 【Chemistry 14】 -C≡C-, -CF 2 O-, -OCF 2 may each be replaced by -, -CH=CH-, by -O-, -CO-O- or -O-CO- in such a way that the O atoms are not directly linked to each other, and in which one or more H atoms may be replaced by halogen, A 3 are, independently of one another in each occurrence, a 1,4-phenylene radical in which one or two CH groups may be replaced by N, or one or two non-adjacent CH 2 represents a 1,4-cyclohexylene or 1,4-cyclohexenylene radical, the group of which may be replaced by -O- or -S-, wherein the radical may be mono- or polysubstituted by halogen atoms, Z 3 are each independently in each occurrence -CF 2 O-, -OCF 2 -, -CH 2 O-, -OCH 2 -, -CH 2 -, -CH 2 CH 2 represents -, -CH=CH-, -C≡C- or a single bond; L 31 and L 32 are each independently F, Cl, CF 3 or CHF 2 represents W represents O or S, and n represents 0, 1 or 2; The liquid crystal medium according to claim 1, further comprising one or more compounds selected from the group consisting of

7. 7. Liquid crystal medium according to claim 5 or 6, comprising one or more compounds of the formula IIE 【Chemistry 15】 In the formula, R 2E1 independently represent H, an alkyl radical having 1 to 7 C atoms, or an alkenyl radical having 2 to 7 C atoms, each of which is unsubstituted or at least monosubstituted with halogen, where in these radicals one or more CH 2 The groups are -O-, -S-, 【Chemistry 16】 -C≡C-, -CF 2 O-, -OCF 2 may be replaced by -, -OC-O- or -O-CO- in such a way that the O atoms are not directly linked to each other; R 2E2 represents independently an alkoxy or alkyl radical having 1 to 7 C atoms, or an alkenyl radical having 2 to 7 C atoms, each of which is unsubstituted or at least monosubstituted with halogen, where in these radicals one or more CH 2 The base is 【Chemistry 17】 may be replaced by Y is H, F, Cl, or CF 3 , CHF 2 or CH 3 represents; L 1 and L 2 are each independently F, Cl, CF 3 or CHF 2 Represents, The liquid crystal medium comprising:

8. Liquid-crystalline medium according to any one of claims 5 to 7, comprising one or more compounds of formula H 【Chemistry 18】 In that formula A represents a q-valent aliphatic, aromatic or heteroaromatic hydrocarbon radical having 1 to 40 C atoms, preferably 6 to 30 C atoms; or a bond with q=2; Sp represents a spacer group or a bond; R S represents H, alkyl having 1 to 12 C atoms or alkenyl having 2 to 12 C atoms; HA is 【Chemistry 19】 represents; Z S -O-, -C(O)O-, -(CH 2 ) z -or-(CH 2 ) z represents O-, or a single bond; preferably -C(O)O-, R H H, O, CH 3 , OH or OR S represents preferably H or O.; R S1 , R S2 , R S3 and R S4 are identical or different and denote alkyl having 1 to 6 C atoms, preferably having 1 to 3 C atoms, very preferably CH 3 and G is H or R S or group Z S - represents HA, The group z is an integer from 1 to 6, q is 1, 2, 3 or 4, preferably 2; The liquid crystal medium comprising:

9. Liquid-crystalline medium according to any one of claims 5 to 8, comprising one or more compounds of the formula HA 【Chemistry 20】 During the ceremony A a 1 or 2 CH 2 represents an alkylene group having 1 to 12 carbon atoms which may be replaced by 1,4-cyclohexylene, and R H represents H or O. The liquid crystal medium comprising:

10. 10. Liquid-crystalline medium according to claim 5, comprising one or more of the compounds of the formulae IV-1 and IV-3. 【Chemistry 21】 In the formula, Alkyl and alkyl' independently of one another denote alkyl having 1 to 7 C atoms, preferably having 2 to 5 C atoms, Alkenyl represents an alkenyl radical having 2 to 5 C atoms, preferably having 2 to 4 C atoms, The liquid crystal medium comprising:

11. Liquid-crystalline medium according to any one of claims 5 to 10, comprising one or more compounds of formula P-1 【Chemistry 22】 In the formula, R P represents a straight-chain alkyl or alkoxy radical having 1 to 6 C atoms, or an alkenyl radical having 2 to 6 C atoms, each of which is unsubstituted or at least monosubstituted by halogen, where in these radicals one or more CH 2 The groups are -O-, -S-, 【Chemistry 23】 -C≡C-, -CF 2 O-, -OCF 2 may be replaced by -, -OC-O- or -O-CO-, respectively, in such a way that the O atoms are not directly linked to each other; X P is a straight chain alkyl with 1 to 6 C atoms, F, Cl, CF 3 , OCF 2 H, OCF 3 , O.C.H.F.F. 3 , OCF 2 CHFCF 3 , OCH=CF 2 , preferably F, OCF 3 or CF 3 , C.H. 3 and L P1 , L P2 and L P3 each independently of the others represents H or F, and L P4 is H or CH 3 and preferably H, The liquid crystal medium comprising:

12. A liquid-crystalline medium according to any one of claims 5 to 11, comprising a compound of the formula PIII-1 【Chemistry 24】 In the formula, R 3 represents an unsubstituted or halogenated linear or branched alkyl radical having 1 to 15 C atoms, in which one or more CH 2 The groups are, independently of one another, 【Chemistry 25】 -C≡C-, -CF 2 may be replaced by -O-, -CH=CH-, -O-, -CO-O- or -O-CO-, respectively, in such a way that the O atoms are not directly linked to each other; L 31 and L 32 are the same or different and represent H or F, Y 3 are the same or different and may be H or CH 3 represents X 3 are the same or different and represent halogen, CN, halogenated alkyl or alkoxy having 1 to 3 C atoms, or halogenated alkenyl or alkenyloxy having 2 or 3 C atoms, preferably F, CN, OCF 3 or CF 3 is most preferably F or CN, and n is independently 0 or 1, preferably n is 0; The liquid crystal medium comprising:

13. Liquid-crystalline medium according to any one of claims 5 to 12, comprising one or more compounds of formula VI 【Chemistry 26】 In the formula, R 6 and R 62 is R as defined in claim 1 2A and R 62 Alternatively, F, Cl, CF 3 or OCF 3 represents, and L 61 , L 62 , L 63 , L 64 , L 65 , and L 66 independently represent H or F, where L 61 , L 62 , L 63 , L 64 , L 65 , and L 66 at least one of represents F, and wherein compounds represented by formulae IIC and IIE are excluded. The liquid crystal medium comprising:

14. A liquid crystal medium according to any one of claims 5 to 13 for use in an LCoS panel.

15. 15. An LCoS panel according to any one of claims 1 to 4, wherein the liquid crystal medium is according to any one of claims 5 to 14.

16. 5. A projection system comprising an LCoS panel according to claim 1, a light source, and a light directing element.

17. Use of a liquid crystal medium according to any one of claims 5 to 15 in an LCoS panel, a projection system, a near eye display or a beam steering application.

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