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 material (LC medium) disclosed herein has negative dielectric anisotropy and high optical anisotropy and is particularly useful in electro-optical displays including projection systems based on vertical alignment (VA) nematic panels.SELECTED DRAWING: Figure 1

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. This liquid crystal medium (LC medium) has negative dielectric anisotropy, extremely high optical anisotropy, and is particularly useful in electro-optical microdisplays or 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, the development of LCoS panels has room for improvement.

[0003] The alignment layer is usually applied on the electrode (when such an electrode exists) to contact the LC medium and induce 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 TV applications, but the alignment strength of the inorganic material often decreases. Careful testing is required for the variable alignment characteristics of these inorganic materials. For LCoS panels, there is a need for an LC medium having high alignment characteristics with respect to the inorganic alignment material. In addition, these devices usually require high light stability and long life under high light intensity and temperature stress (such as a standard operating temperature of about 60 to 70 °C). Some applications also require a high temperature range (as is the case for outdoor devices and vehicles) and short response times.

[0004] Another problem observed in the prior art is that the use of conventional LC media in LCoS panels often results in defects within the display (such as misalignment, white spots, non-uniformity, bubbles, and dark regions) due to the severe temperatures and irradiations during use. Thus, it is desirable to provide an LC medium that results in a reduction of displacement defects after continuous use. This means that they must be stable in themselves and must be well combined with adjacent materials, for example, an inorganic alignment layer.

[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, together with a high specific resistance, enable a wide operating temperature range, short response times, and low threshold voltages, multiplicity of gray shades, high contrast, have high reliability, and high values of VHR after UV irradiation. SUMMARY OF THE INVENTION

[0006] The present invention is based on the object of providing a novel and suitable LC medium for use in devices that does not have the above-mentioned drawbacks or has 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 medium suitable for a phase modulation display. Here, the delay of the optical signal is modulated for each pixel. The resulting reflected light can have an intensity controlled by interference. The use in small projectors is, for example, in the field of augmented reality applications in near-eye devices, head-up displays, in-vehicle projection displays or the like. These objects have been achieved according to the present invention by the materials and processes described in this application. In particular, it has surprisingly been found that the use of the liquid crystal hosts described below makes it possible to achieve the advantageous effects as described above.

[0008] In one aspect, the present invention a) Formula I

Chemical formula

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[0009] The present invention further relates to a liquid crystal medium as disclosed above for an LCoS panel. The present invention further relates to a process for preparing an LC medium as described above and below, which comprises mixing one or more compounds represented by formulas I, III and IV, 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 invention. The light guiding element can be selected from a lens, a mirror, a half mirror, a prism or the like.

[0010] The present invention further relates to the use of an LC medium according to the invention in a display. The present invention further relates to an LC display comprising an LC medium according to the 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 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 invention.

[0011] The present invention further relates to an LC display of the VA or PSA type, 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 compounds are polymerized between the substrates of the display.

[0012] 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, which comprises filling or otherwise providing the LC medium as described above and below between the substrates of the panel and sealing it. Preferred embodiments are also disclosed in the dependent claims and can also be adopted from the description.

Brief Description of the Drawings

[0013]

Figure 1

Mode for Carrying Out the Invention

[0014] The display according to the present invention preferably has two electrodes in the form of transparent layers, which are applied to one or both of the substrates. In a typical reflective display, a single continuous transparent electrode is applied to a transparent substrate. The opposite electrode is formed as individually addressable pixels.

[0015] Surprisingly, it has been found that the use of a liquid crystal medium according to the present invention can achieve a display with fast response time, low threshold voltage, high birefringence, and 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, especially inorganic alignment materials.

[0016] The LC medium according to the present invention exhibits the following advantageous properties when used in VA or FFS displays: - 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.

[0017] 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.

[0018] In particular, the liquid crystal medium according to the present invention advantageously exhibits a ratio γ1 / K1 of rotational viscosity to splay elastic constant that is low. This contributes, inter alia, to an improvement in 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 the LC displays containing them.

[0019] The LCOS panel and medium preferably additionally comprise the following: d) 0.1% to 0.9% of one or more compounds represented by formula ST-1

Chemical formula

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[0020] In one aspect of the present invention, a certain liquid crystal medium is preferred, which further comprises one or more compounds selected from the group represented by formula e): e) Formulae IIA, IIB, IIC, IID and IIE

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[0021] In one embodiment of the present invention, a certain liquid crystal medium is preferred, where the medium contains one or more compounds selected from the group of compounds represented by formulas T-1 to T-3:

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Chemical formula

[0022] In formulas T-1 and T-2, preferably, R 11is an n-alkyl or alkenyl having up to 7 carbon atoms, most preferably an n-alkyl having 1 to 5 carbon atoms, and R 12 is an n-alkoxy or alkenyloxy having 1 to 6 carbon atoms, most preferably an n-alkoxy having 1 to 4 carbon atoms, and, in formula T-3, preferably, R 11 is an n-alkyl or alkenyl having up to 7 carbon atoms, most preferably an n-alkyl having 1 to 5 carbon atoms, and R 12 is an n-alkyl or alkenyl having up to 7 carbon atoms, most preferably an n-alkyl having up to 5 carbon atoms.

[0023] The liquid crystal medium according to the present invention preferably contains one or more compounds represented by formula T-1, which is preferably selected from the group of compounds represented by formulas T-1a to T-1c, and most preferably is represented by formula T-1a.

Chemical formula

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[0024] The liquid crystal medium according to the present invention preferably contains one or more compounds represented by formula T-3, which is preferably selected from the group of compounds represented by formulas T-3a to T-3c, preferably is represented by formula T-3a and / or T-3c, and most preferably is represented by formula T-3c,

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[0025] In a preferred embodiment of the present invention, the liquid crystal medium comprises one or more compounds selected from the group of compounds represented by Formulas I-1 to I-3:

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Chemical formula

[0026] Preferred compounds represented by Formulas IIA, IIB, IIC, IID and IIE are shown below:

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Chem.

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Chem.

[0027] The compounds represented by highly preferred formula IID are selected from the following sub-formulas:

Chem.

Chem.

Chem.

Chem.

[0028] In a preferred embodiment, the medium contains one or more compounds represented by formula IID-10a, [Chemical formula] In the formula, the groups and parameters that appear have the meanings given under formula IID above, and preferably, R 2D is [Chemical formula] represents, in which formula, r is 0, 1, 2, 3, 4, 5, or 6, and s is 1, 2, or 3.

[0029] In a preferred embodiment, the medium contains one or more compounds represented by the following formula IIE: [Chemical formula] [Chemical formula] In the formula, m is 1, 2, 3, or 4, preferably 2 or 4.

[0030] More preferred media according to the present invention contain one or more of the compounds represented by formulae IIA-2, IIA-8, IIA-10, IIA-16, IIA-18, IIA-40, IIA-41, IIA-42, IIA-43, IIB-2, IIB-10, IIB-16, IIC-1, IIC-3, IID-4, IID-10, and IIE-1.

[0031] Highly preferred media according to the present invention contain one or more compounds represented by formula IIB-2, [Chemical formula] In the formula, alkyl and alkyl* each independently represent a linear alkyl radical having 1 to 6 carbon atoms, and (O) represents an oxygen atom or a single bond. In particular, there are compounds IIB-2-1 and IIB-2-2:

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Chemical formula

[0032] A preferred medium according to the present invention preferably contains a compound represented by at least one formula IIC-1 in an amount of 0.5 to 5% by weight, in particular 1 to 3% by weight.

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[0033] In particular, the medium contains one or more compounds represented by formula IIA-2 selected from the following sub-formulas:

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[0034] Alternatively, preferably, in addition to the compounds represented by formulas IIA-2-1 to IIA-2-5, the medium contains one or more of the compounds represented by formulas IIA-2a-1 to IIA-2a-5:

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[0035] In particular, the medium contains one or more compounds represented by formula IIB-10 selected from the following sub-formulas:

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Chemical formula

[0036] Alternatively, preferably, in addition to the compounds represented by Formulae IIB-10-1 to IIB-10-5, the medium comprises one or more of the compounds represented by Formulae IIB-10a-1 to IIB-10a-5:

Chemical formula

[0037] Most preferably, the medium according to the invention comprises one or more of the compounds represented by Formula IIE, especially the compounds represented by Formulae IIE-1-1 to IIE-1-8, and most preferably one or more of the compounds represented by Formulae IIE-1-1-1 to IIE-1-1-4:

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[0038] The compound represented by Formula III is preferably selected from the compounds represented by Formulae III-1, III-2 and / or III-4,

Chemical formula

[0039] The liquid crystal medium according to the present 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 a 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.

[0040] 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, and is preferably the compound represented by formula III-1-6.

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[0041] 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, and is preferably the compound represented by formula III-2-6.

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[0042] Optionally, the medium contains one or more compounds represented by formula IIIA-1 and / or IIIA-2,

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[0043] The compounds represented by formula IIIA-1 and / or IIIA-2 are preferably additionally contained in the medium, instead of or in addition to the compounds represented by formula III. The extremely preferred compounds represented by formulae IIIA-1 and IIIA-2 are as follows: [Chemical formula] [Chemical formula] In the formula, the alkoxy is a linear alkoxy radical having 1 to 6 C atoms or, alternatively, -(CH2) where n is 2, 3, 4, or 5 n represents F, preferably C2H4F.

[0044] In a preferred embodiment of the present invention, the medium contains one or more compounds represented by formula III-3, [Chemical formula] wherein R 31 , R 32 are the same or different and represent H, an alkyl or alkoxy radical having 1 to 15 C atoms, and one or more CH2 groups in these radicals are independently of each other optionally replaced in such a way that the O atoms are not directly linked to each other by -C≡C-, -CF2O-, -OCF2-, -CH=CH-, [Chemical formula] -O-, -CO-O-, or -O-CO- and where, in addition, one or more H atoms may be replaced by halogen.

[0045] The compound represented by formula III-3 is preferably selected from the group of compounds represented by formulae III-3-1 to III-3-10: [Chemical formula] [Chemical formula] wherein R 32is alkyl having 1 to 7 C atoms, preferably ethyl, n-propyl or n-butyl, or alternatively cyclopropylmethyl, cyclobutylmethyl or cyclopentylmethyl, or alternatively, where n is 2, 3, 4, or 5, -(CH2) n represents F, preferably C2H4F.

[0046] In a preferred embodiment of the present invention, the medium comprises one or more of the compounds represented by Formulas III-4 to III-6, preferably the compound represented by Formula III-5,

Chemical formula

[0047] In a preferred embodiment, the medium according to the present invention comprises one or more compounds represented by Formula III, selected from the group of compounds represented by Formulas III-7 to III-9, preferably the one represented by Formula III-8,

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[0048] In a preferred embodiment, the medium comprises one or more compounds represented by Formula IV,

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[0049] The compound represented by formula IV is preferably selected from the group of compounds represented by formulas IV-1 to IV-4,

Chemical formula

[0050] Preferably, one or more compounds represented by formula IV are selected from formulas IV-1, IV-2 and IV-3, and more preferably, it is the compound represented by formula IV-2, More preferably, it is IV-2 alone or in combination with either IV-1 or IV-3, most preferably in combination with IV-3. Preferably, in addition to the compound represented by formula IV-2, the medium contains one or more compounds selected from the compounds represented by formulas IV-1, IV-3 and IV-4.

[0051] Preferably, the medium contains one or more compounds selected from the compounds represented by formulas IV-1-1 to IV-1-4.

Chemical formula

[0052] Most preferably, the medium according to the present invention contains one or more of the compounds represented by formulas IV-1-1 to IV-1-6.

Chemical formula

[0053] In a preferred embodiment, the medium according to the present invention contains one or more compounds represented by formula IV-3,

Chemical formula

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[0054] In a preferred embodiment, the medium contains, in addition to the compounds represented by formulas IV-3-1 to IV-3-6 in particular, one or more of the compounds represented by formulas IV-3-7 to IV-3-9.

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Chemical formula

[0055] Preferably, the concentration of the compounds represented by formulas 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 compounds represented by formula IV-1 therein is in the range of 1% to 30%.

[0056] Most preferably, the medium according to the present invention contains a compound of formula IV-4, particularly one selected from the compounds represented by formulas IV-4-1 to IV-4-3, especially the one represented by formula IV-4-3.

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[0057] In a preferred embodiment, the medium according to the present invention contains one or more compounds selected from the compounds represented by formulas IA-1 to IA-18:

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[0058] The LC medium according to the invention preferably comprises one or more compounds represented by formula IVa,

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[0059] Preferred compounds represented by formula IVa are shown below:

Chem.

[0060] The medium according to the invention preferably comprises 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.

[0061] Preferably, the medium comprises one or more compounds represented by formulas IVb-1 to IVb-3, [Chemistry] In the formula, alkyl and alkyl* each independently represent a linear alkyl radical having 1 to 6 C atoms, and alkenyl and alkenyl* each independently represent a linear alkenyl radical having 2 to 6 C atoms.

[0062] The proportion of the compounds represented by Formulas IV-1 to IV-3 in the entire mixture is preferably less than 3% by weight, particularly 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.

[0063] A very particularly preferred biphenyl is [Chemistry] wherein alkyl* represents an alkyl group having 1 to 6 C atoms and preferably represents n-propyl or n-butyl. The medium according to the 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 propyl.

[0064] In a preferred embodiment, the medium according to the invention contains one or more compounds represented by Formula V, [Chemistry] wherein R 51 and R 52 each represent 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, [Chemistry] represents [Chemistry] and represents [Chemistry] represents [Chemistry] and represents Z 51 and Z 52 each independently represents -CH2-CH2-, -CH2-O-, -CH=CH-, -C≡C-, -COO- or a single bond, and n is 1 or 2.

[0065] The compound represented by formula V is preferably selected from the compounds represented by formulas V-1 to V-14: [Chemistry] [Chemistry] In the formula, R 51 and R 52 have the meanings shown for formula V above.

[0066] R 51 and R 52 preferably each independently represents 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.

[0067] In a preferred embodiment, the medium according to the invention comprises one or more compounds represented by formula Vb, [Chemistry] In the formula, 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, [Chemical formula] represents [Chemical formula] and represents [Chemical formula] represents [Chemical formula] and represents Z 51 , Z 52 each independently represents -CH2-CH2-, -CH2-O-, -CH=CH-, -C≡C-, -COO- or a single bond, and n is 2.

[0068] The compound represented by formula Vb is preferably selected from the compounds represented by formulas Vb-1 to Vb-2: [Chemical formula]

[0069] In a preferred embodiment of the present invention, the medium further contains one or more compounds represented by formula VI, [Chemical formula] In the formula, R 6 and R 62 have the meaning of R 2A as defined in claim 1, and R 62 alternatively represents F, Cl, CF3 or OCF3, preferably F, 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 which represents F, and wherein the compounds represented by Formulas IIC and IIE are excluded.

[0070] 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

[0071] 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.

[0072] In a preferred embodiment of the present invention, the medium further comprises one or more compounds represented by Formula VIA,

Chemical formula

[0073] Very preferably, the medium according to the invention comprises a compound represented by formula VIA-1 and / or formula X, [Chemical formula] in which R 6 and m have the meanings defined above, and preferably R 6 represents methyl, ethyl, n-propyl, n-butyl, or n-pentyl, and m is 2, 3, or 4. In certain preferred embodiments, R 6 represents n-propyl, and m represents 2.

[0074] In a preferred embodiment of the invention, the medium additionally comprises one or more of the compounds represented by formulas VII-1 to VII-9, [Chemical formula] [Chemical formula] In the formula, R 7 represents a linear alkyl or alkoxy radical having 1 to 6 C atoms, or a linear alkenyl radical having 2 to 6 C atoms, and w is an integer from 1 to 6. Particularly preferred is a mixture comprising at least one compound represented by formula VII-9.

[0075] 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

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Chemical formula

[0076] b) Preferred liquid crystal media according to the invention include one or more substances containing tetrahydronaphthyl or naphthyl units, such as compounds represented by formulas N-1 to N-5,

Chemical formula

[0077] 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

[0078] Particularly preferred compounds represented by formulas BC and CR are compounds BC-1 to BC-7 and CR-1 to CR-5.

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Chemical formula

[0079] d) Preferred mixtures contain one or more indane compounds of formula In,

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[0080] Preferred compounds of formula In are the compounds of formulae In-1 to In-16 shown below:

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Chemical formula

[0081] e) Preferred mixtures further comprise one or more of the compounds represented by formulas L-1 to L-11,

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[0082] The compounds represented by formulas L-1 to L-11 are preferably employed at a concentration of 5 to 15% by weight, especially 5 to 12% by weight, and very particularly preferably 8 to 10% by weight.

[0083] f) Preferred mixtures additionally comprise one or more compounds represented by formula IIA-Y,

Chemical formula

[0084] The preferred compounds represented by formula IIA-Y are selected from the group consisting of the following sub-formulas,

Chemical formula

Chemical formula

Chem.

[0085] Particularly preferred compounds represented by formula IIA-Y are selected from the group consisting of the following sub-formulas:

Chem.

[0086] g) The medium additionally contains one or more compounds selected from the compounds represented by formulas P-1 to P-4:

Chem.

Chemical formula

[0087] Preferred compounds represented by formulas P1 to P4 are listed below:

Chemical formula

[0088] The compound represented by formula P-1 has the property of stabilizing for liquid crystal media. In a preferred embodiment, the medium according to the invention comprises 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.

[0089] Preferably, the liquid crystal medium according to the invention comprises one or more compounds represented by formula H,

Chemical formula

Chemical formula

[0090] In formula H, A preferably represents an aromatic or heteroaromatic hydrocarbon group having 4 to 40 carbon atoms, including 1, 2, 3 or 4 aromatic rings (which may include fused rings, which may be linked directly or via an alkylene linking group having 1 to 12 carbon atoms), where one or more H atoms are optionally replaced by alkyl or alkoxy having 1 to 6 carbon atoms, or alkenyl having 2 to 6 carbon atoms, or CN, CF3 or halogen, and where one or more CH2 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(C1-C4 alkyl)-, -CO-, -CO-O-, -O-CO-, -O-CO-O-, -CH=CH- or -C≡C-.

[0091] Preferred aliphatic groups are alkylene, cycloalkylene, more preferably -(CHR S5 ) s -, where R S5 is H or alkyl having 1 to 5 carbon 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 carbon atoms. The compounds represented by formula H are described in EP 3354710 A1 and EP 3354709 A1. The compounds represented by formula H are preferably applied in the range of 0.1 to 0.3% (by weight).

[0092] In a preferred embodiment, the medium is of the formula H-A

Chemical formula

[0093] Group A a is preferably

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[0094] The compound represented by formula H is preferably selected from the compounds represented by formulas H - 1 to H - 12:

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Chemical formula

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[0095] Preferred compounds represented by formula H-10 are selected from the compounds represented by formula H-10-1:

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[0096] Preferred compounds represented by formula H-11 are selected from the compounds represented by formula H-11-1:

Chemical formula

[0097] Preferred compounds represented by formula H-12 are selected from the compounds represented by formula H-12-1:

Chemical formula

[0098] Preferred stabilizer H is as follows: [Chemical formula] [Chemical formula]

[0099] Preferably, the medium according to the present invention contains a compound selected from the group of compounds represented by formulas ST-1 to ST-13: [Chemical formula] [Chemical formula] [Chemical formula] In the formula, R ST represents H, an alkyl or alkoxy radical having 1 to 15 carbon atoms, where, in addition, one or more CH2 groups in these radicals are, independently of each other, -C≡C-, -CF2O-, -OCF2-, -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 R ST is alkyl or cyclopentyl having 1 to 7 carbon atoms, [Chemical formula] in each occurrence, which may be the same or different, [Chemical formula] or [Chemical formula] represents, Z ST each independently represents -CO-O-, -O-CO-, -CF2O-, -OCF2-, -CH2O-, -OCH2-, -CH2-, -CH2CH2-, -(CH2)4-, -CH=CH-, -CH2O-, -C2F4-, -CH2CF2-, -CF2CH2-, -CF=CF-, -CH=CF-, -CF=CH-, -CH=CH-, -C≡C- or a single bond, L 1 and L 2 each independently represents F, Cl, CH3, CF3 or CHF2, p is 0, 1 or 2, q represents 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10.

[0100] Among the compounds of formula ST, particularly preferred are the compounds represented by formula ST-1 and ST-3, and in particular the following: [Chemical formula] [Chemical formula]

[0101] Highly particularly preferred mixtures according to the invention comprise one or more stabilizers from the group of compounds represented by formulae ST-1a, ST-1b-1 and ST-1c-1: [Chemical formula]

[0102] The compounds represented by Formulas ST-1 to ST-12 are preferably present in the liquid crystal mixture according to the present invention in an amount of 0.1 to 0.5% each based on the mixture. However, the total proportion of the compounds represented by Formulas ST-1 to ST-12 based on the mixture according to the present invention should not exceed 2%. The medium according to the present invention preferably has negative dielectric anisotropy.

[0103] 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), unevenness, and contamination 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.

[0104] 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.

[0105] Unless otherwise indicated, the term "LC display" as used herein refers 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. Sizes range from microdisplays to large screens. Addressing can be achieved in such a way that the LC display includes 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.

[0106] 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:

Chem.

[0107] The cyclohexylene ring is a trans - 1,4 - cyclohexylene ring. In the above and below,

Chem.

[0108] Group

Chem.

[0109] "Carbon-based" represents a monovalent or polyvalent organic group containing at least one carbon atom, which may contain no further atoms (e.g., -C≡C-), or optionally 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" additionally represents a carbon group containing one or more H atoms and optionally one or more heteroatoms such as N, O, S, B, P, Si, Se, As, Te, or Ge.

[0110] "Halogen" represents F, Cl, Br, or I, preferably F or Cl. -CO-, -C(=O)-, and -C(O)- represent a carbonyl group, i.e.,

Chem.

[0111] Terms such as "alkyl", "aryl", "heteroaryl", etc. also encompass polyvalent groups such as alkylene, arylene, heteroarylene, etc. The term "aryl" represents an aromatic carbon group or a group derived therefrom. The term "heteroaryl" preferably means "aryl" as defined above, containing one or more heteroatoms selected from N, O, S, Se, Te, Si, and Ge.

[0112] In this 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. As used herein, a branched alkyl is an alkyl having a secondary and / or tertiary, preferably secondary, carbon atom, and is preferably isopropyl, s-butyl, isobutyl, isopentyl, 2-methylhexyl or 2-ethylhexyl, 2-methylpropyl, 2-pentyl, 3-pentyl, 2-methylbutyl, 3-methylbutyl.

[0113] As used herein, a cyclic alkyl group is a cyclic aliphatic radical or alkyl group which may be saturated or partially unsaturated and in which a methylene group is replaced by a cyclic aliphatic group (i.e., cycloalkylalkyl or alkylcycloalkylalkyl), and is preferably cyclopropyl, methylcyclopropyl, cyclobutyl, methylcyclobutyl, cyclopentyl, methylcyclopentyl, cyclopenta-1-enyl, cyclopropylmethyl, cyclopropylethyl, cyclobutylmethyl, cyclobutylethyl, cyclopentylmethyl, cyclopentylethyl, cyclopenta-1-enylmethyl.

[0114] As used herein, an alkoxy radical is straight-chain or branched and contains from 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.

[0115] As used herein, an alkenyl radical is preferably an alkenyl radical having from 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 from 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.

[0116] As used herein, alkynyl is understood to mean an alkynyl radical that is straight-chain or branched and has from 2 to 15 carbon atoms and contains at least one C-C triple bond. 1- and 2-propynyl, and 1-, 2- and 3-butynyl are preferred.

[0117] Preferred carbon and hydrocarbon groups are linear, branched or cyclic alkyl, alkenyl, alkynyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy and alkoxycarbonyloxy which may be optionally substituted and have 1 to 40, preferably 1 to 20 and most preferably 1 to 12 C atoms, aryl or aryloxy which may be optionally substituted and have 5 to 30, preferably 6 to 25 C atoms, or alkylaryl, arylalkyl, alkylaryloxy, arylalkyloxy, arylcarbonyl, aryloxycarbonyl, arylcarbonyloxy and aryloxycarbonyloxy which may be optionally substituted and have 5 to 30, preferably 6 to 25 C atoms, where one or more of the C atoms may also be optionally replaced by one or more heteroatoms selected from N, O, S, Se, Te, Si and Ge.

[0118] Even more preferred carbon and hydrocarbon groups are C1-C 20 alkyl, C2-C 20 alkenyl, C2-C 20 alkynyl, C3-C 20 allyl, C4-C 20 alkyldienyl, C4-C 20 polyenyl, C6-C 20 cycloalkyl, C4-C 15 cycloalkenyl, C6-C 30 aryl, C6-C 30 alkylaryl, C6-C 30 arylalkyl, C6-C 30 alkylaryloxy, C6-C 30 arylalkyloxy, C2-C 30 heteroaryl, C2-C 30 heteroaryloxy. Particularly preferred are C1-C 12 alkyl, C2-C 12 alkenyl, C2-C 12 alkynyl, C6-C 25 aryl and C2-C 25 heteroaryl.

[0119] More preferred carbon and hydrocarbon groups are linear, branched or cyclic alkyls having from 1 to 20, preferably from 1 to 12 C atoms, which are unsubstituted or mono- or polysubstituted by F, Cl, Br, I or CN, and wherein one or more non-adjacent CH2 groups are each independently replaced, in a way such that O and / or S atoms are not directly linked to each other, by -C(R x )=C(R x )-, -C≡C-, -N(R x )-, -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O-.

[0120] R x preferably represents H, F, Cl, CN, a linear, branched or cyclic alkyl chain having from 1 to 25 C atoms, wherein in addition one or more non-adjacent C atoms may be replaced by -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O-, and wherein one or more H atoms may be replaced by F or Cl, or represents an optionally substituted aryl or aryloxy group having from 6 to 30 C atoms, or an optionally substituted heteroaryl or heteroaryloxy group having from 2 to 30 C atoms.

[0121] 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, trifluoromethyl, perfluoro-n-butyl, 2,2,2-trifluoroethyl, perfluorooctyl, perfluorohexyl, etc. Preferred alkenyl groups include, for example, ethenyl, propenyl, butenyl, pentenyl, cyclopentenyl, hexenyl, cyclohexenyl, heptenyl, cycloheptenyl, octenyl, cyclooctenyl, and the like. Preferred alkynyl groups include, for example, ethynyl, propynyl, butynyl, pentynyl, hexynyl, octynyl, and the like.

[0122] Preferred alkoxy groups include, 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-decox, n-undecox, n-dodecox, and the like. Preferred amino groups include, for example, dimethylamino, methylamino, methylphenylamino, phenylamino, and the like.

[0123] Aryl groups and heteroaryl groups can be monocyclic or polycyclic, i.e., 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. Heteroaryl groups preferably contain one or more heteroatoms selected from O, N, S, and Se.

[0124] Particularly preferred are monocyclic, bicyclic, or tricyclic aryl groups having 6 to 25 carbon atoms, and monocyclic, bicyclic, or tricyclic heteroaryl groups having 5 to 25 ring atoms, which optionally contain fused rings and can 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 can 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.

[0125] Preferred aryl groups include, 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 groups and the like.

[0126] 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.

[0127] 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 groups 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.

[0128] (Non-aromatic) alicyclic groups 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. Also 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 CH2 groups may be replaced by -O- and / or -S-.

[0129] 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.

[0130] Preferred substituents are, for example, solubilizing 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), particularly bulky groups such as the t-butyl group or an optionally substituted aryl group.

[0131] Preferred substituents (hereinafter also referred to as "L") are, for example, F, Cl, Br, I, -CN, -NO2, -NCO, -NCS, -OCN, -SCN, -C(=O)N(R x )2, -C(=O)Y 1 , -C(=O)R x , -N(R x )2, a straight-chain or branched alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy each having 1 to 25 C atoms, wherein one or more H atoms may optionally be replaced by F or Cl, an optionally substituted silyl having 1 to 20 Si atoms, or an optionally substituted aryl having 6 to 25, preferably 6 to 15, C atoms, wherein R x represents H, F, Cl, CN, or a straight-chain, branched, or cyclic alkyl having 1 to 25 C atoms, wherein one or more non-adjacent CH2 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 wherein one or more H atoms are each optionally replaced by F, Cl, P- or P-Sp-, and Y 1 represents halogen.

[0132] "Substituted silyl or aryl" preferably means substituted by halogen, -CN, R 0 , -OR 0 , -CO-R 0 , -CO-OR 0 , -O-CO-R 0 or -O-CO-OR 0 , where R 0 represents H or an alkyl having 1 to 20 C atoms. Particularly preferred substituents L are, for example, F, Cl, CN, NO2, CH3, C2H5, OCH3, OC2H5, COCH3, COC2H5, COOCH3, COOC2H5, CF3, OCHF3, OC2F5, and further phenyl.

[0133] In addition, the LC medium according to the present invention may contain one or more further constituents or additives, preferably 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, selected from the list including but not limited to these. The LC medium according to the present invention may contain one, two, or three chiral dopants, preferably one chiral dopant.

[0134] Preferred embodiments, employed alone or in combination with each other, are listed below. The medium according to the present invention preferably contains the following: - A compound represented by formula I at a concentration in the range of 15% to 60%, preferably 20% to 50%, and most preferably 25% to 45%; - One or more compounds selected from the compounds represented by formula ST-1 and ST-12 at a concentration in the range of 0.01% to 0.85%, preferably 0.05% to 0.60%, and most preferably 0.1% to 0.5%; - A compound represented by formula H, preferably formula HA, more preferably formula H-1, at a concentration in the range of 0.008% to 0.08%, preferably 0.012% to 0.06%, and most preferably 0.015% to 0.04%; - One or more compounds represented by formula IIA, IIB, IIC, IID, IIE, and III at a total concentration in the 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 represented by formula III-1 and / or III-2, more preferably represented by formula III-2, in a total concentration in the range of 0% to 15%, more preferably 1% to 12%, most preferably 2% to 10%, especially 3% to 8%; - One or more compounds represented by formula IIA in a total concentration in the 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 IIB-2 in a total concentration in the range of 1% to 30%, more preferably 1% to 25%, and most preferably 1% to 10%; - One or more compounds represented by formula IIB-10 in a total concentration in the range of 1% to 20%, more preferably 1% to 15%, and most preferably 1% to 10%; - One or more compounds represented by formula IIB-2 and / or IIB-10 in a total concentration in the range of 1% to 30%, more preferably 1% to 20%, and most preferably 2% to 15%; - One or more compounds selected from compounds represented by formula IIC, preferably represented by IIC-1 and IIC-2, more preferably represented by formula IIC-1, in a total concentration in the range of 1% to 25%, more preferably 1% to 20%, and most preferably 1% to 15%; - One or more compounds represented by formula IIE, preferably represented by formula IIE-1, in a total concentration in the range of 1% to 18%, more preferably 1% to 15%, and most preferably 1% to 12%; - One or more compounds represented by formula III (more preferably selected from formula III-1, IIIA-1, III-2 and IIIA-2) in a total concentration in the range of 3% to 30%, more preferably 5% to 25%, and most preferably 7% to 22%; - Two or more trane compounds represented by formula I, T-1, T-2 and T-3 (more preferably selected from formula I-1, I-2, T-1 and T-3) in a total concentration in the range of 25% to 80%, more preferably 30% to 75%, and most preferably 35% to 65%; - A total concentration in the range of 10% to 65%, more preferably 18% to 60%, and most preferably 18% to 56% of one or more trand compounds represented by formulas T-1, T-2, and T-3 (more preferably, those selected from formulas T-1 and T-3); - One or more compounds selected from the compounds represented by formula IV-1 / 2 / 3 / 4 at a concentration in the range of 6% to 40%, preferably 7% to 38%, and most preferably 8% to 37%; - 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%.

[0135] The LC medium according to the present invention preferably advantageously has a nematic phase of ≦ -20°C to ≧ 90°C, particularly preferably ≦ -30°C to ≧ 100°C, and most particularly preferably ≦ -40°C to ≧ 105°C. In a preferred embodiment, the medium according to the present invention has a clearing temperature (clearing point) of 80°C or higher, more preferably 90°C or higher, more preferably 100°C or higher, particularly 105°C or higher.

[0136] 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 transparency (phase transition to an isotropic phase) occurs even 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 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 a conventional method.

[0137] The liquid crystal mixture preferably has a nematic phase range of at least 60K and a kinematic viscosity ν of at most 30 mm 2 ·s -1 at 20°C 20It has the following. The mixture is nematic at a temperature of -20 °C or lower, preferably -30 °C or lower, and extremely preferably -40 °C or lower.

[0138] The medium according to the present invention has a birefringence (Δn) in the range of 0.085 to 0.28, preferably 0.13 to 0.26, particularly 0.15 to 0.255. In a preferred embodiment, the medium has a birefringence in the range of 0.15 to 0.20, preferably 0.16 to 0.19. In an alternative preferred embodiment, particularly for phase modulation, the medium has a birefringence of 0.19 to 0.28, preferably 0.2 to 0.27, and specifically 0.21 to 0.26.

[0139] In a preferred embodiment, the medium according to the present invention has a dielectric anisotropy Δε of -2.5 to -6.5, preferably -2.8 to -5.2, particularly -3.5 to -4.9. In an extremely preferred embodiment, the liquid crystal mixture according to the present invention has a dielectric anisotropy Δε of -3.8 to -4.8.

[0140] Rotational viscosity at 20 °C γ1 is preferably in the range of 90 to 300 mPa·s, more preferably 100 to 290 mPa·s. The medium according to the present invention has an elastic constant K1 in the range of 16 to 22 pN, more preferably 18 pN or more. In a preferred embodiment, for the medium according to the present invention, the ratio γ1 / K1 of the rotational viscosity to the elastic constant of the spray is 15 mPa·s·pN -1 or less.

[0141] The liquid crystal medium according to the present invention has a relatively low threshold voltage (V0) value. 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 (V0), also called the Frederiks threshold, unless explicitly stated otherwise.

[0142] In addition, the liquid crystal medium according to the present invention has a high value of voltage holding ratio in a liquid crystal cell. Generally, a liquid crystal medium having a low addressing voltage or threshold voltage exhibits a lower voltage holding ratio than one having a higher addressing voltage or threshold voltage, and vice versa.

[0143] For the present invention, the term "dielectrically positive compound" represents a compound having Δε > 1.5, the term "dielectrically neutral compound" represents one having -1.5 ≤ Δε ≤ 1.5, and the term "dielectrically negative compound" represents one having Δε < -1.5. The dielectric anisotropy of the compound is determined here by dissolving 10% of the compound in the 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 is always lower than the capacitive threshold of each liquid crystal mixture being investigated.

[0144] All temperature values shown for the present invention are in °C. The mixture according to the present invention is suitable for all VA-TFT applications such as, for example, VAN, MVA, (S)-PVA, ASV, PSA (polymer sustained alignment 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.

[0145] The 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 by an active liquid crystal layer having a twisted nematic orientation that can be switched between a homeotropic orientation and a homogeneous orientation by the application of a voltage. Although LCoS microdisplays are small, typically having a diagonal of less than 1 inch, they can nevertheless achieve high resolution.

[0146] Due to the small pixel size, the cell thickness in LCoS displays is also extremely small, typically in the range of 1 - 2 μm. Therefore, the liquid crystal phases used in these displays need to have a high value of optical anisotropy Δn, in contrast to conventional reflective LC displays that usually require LC phases with a low Δn.

[0147] 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. Such inorganic alignment layers are particularly suitable for LCoS panels having a high light intensity. A typical and preferred material for these layers is silica (SiO x ) which is applied using specific deposition techniques.

[0148] An LCoS device provides a high-density array of light modulation elements or pixels within a small aperture (e.g., a few centimeters wide). The pixels are typically on the order of 10 microns or less, which means that the optical system can be made compact. The LCoS device is typically reflective, which means that the circuitry driving the LCoS pixels can be buried under the reflective surface. This results in a higher aperture ratio and means that there is little dead space between the pixels. The LCoS panel uses a silicon backplane that has the advantage that the pixels are optically flat. This is particularly important for phase modulation devices.

[0149] Accordingly, in a preferred embodiment, and referring to FIG. 1, there is provided an LCoS panel 100 sandwiched between a transparent glass layer 110 having a transparent electrode 120, a pixelated mirror 150 mounted on a silicon CMOS backplane 160, and its mount (not shown), the mirror being segmented into a two-dimensional array of individually addressable pixels. Each pixel is individually drivable by a voltage signal to provide a local phase change to at least one polarization or phase component of an optical signal, thereby providing a two-dimensional array of phase manipulation regions. The pre-alignment of the liquid crystal 140 is provided by alignment layers 131 and 132.

[0150] The LCOS panel is useful for integration into optical devices. The described LCOS panel outputs spatially modulated light in reflection. The reflective LCoS panel has the advantage of resulting in a high fill factor (typically greater than 90 percent) and high resolution because the signal lines, gate lines, and transistors are beneath the mirror surface. Another advantage of using a reflective LCOS spatial light modulator is that the thickness of the liquid crystal layer can be halved compared to the thickness that would have been required if a transmissive device were used. This significantly improves the switching speed of the liquid crystal (a key advantage for video projection).

[0151] Examples of devices that include an optical component according to the present invention are a holographic projector, a head-up display including at least one holographic projection channel, a driver monitoring system for a head-up display, more preferably an infrared holographic projector for a driver monitoring system of a head-up display, an augmented reality head-up display "AR-HUD" including eye tracking or head tracking, an image generation unit, and an integrated infrared holographic illuminator for head tracking or eye tracking.

[0152] The spatial light modulator can be used to display a diffraction pattern including a computer-generated hologram. If the hologram is a phase-only hologram, a spatial light modulator that modulates phase is required. If the hologram is a full complex hologram, a spatial light modulator that modulates both phase and amplitude may be used, or a first spatial light modulator that modulates phase and a second spatial light modulator that modulates amplitude may be used.

[0153] Other preferred devices include infrared imagers, wavelength selective switches, LCoS-SLMs, LIDAR systems, wavelength division multiplexing (WDM) systems, reconfigurable optical add-drop multiplexers (ROADMs), and non-mechanical beam steering, such as steerable electro-optical evanescent refraction (SEEOR) prisms as disclosed in the article by P. McManamon, 2006, "Agile Nonmechanical Beam Steering" Opt. Photon. News 17(3): 24-29.

[0154] This technology incorporates an LCoS panel and a red, green, and blue (RGB) light source. The red, green, and blue (RGB) light source is configured to emit red, green, and blue light either simultaneously or at different times (e.g., time multiplexed RGB LEDs or laser diodes). As an example, the light source is an RGB light source that uses an array of red, green, and blue micro-LEDs as proposed, for example, in EP3539157 A1.

[0155] RGB refers to the three primary colors of light, red, green, and blue, from which other colors and white can be formed. A conventional single LED can only emit monochromatic (single color) light that is one of these three primary colors. To create more colors, three LEDs can be used together for an RGB mix. RGB LEDs generally have three single color LEDs arranged in close proximity to each other, often in the same package, and the colors are red, green, and blue. If all the LEDs of an RGB-LED emit light proportionally at the same luminous intensity and an appropriate type of optical system is used, the light emitted from the RGB-LED will appear white to the human eye.

[0156] Using an RGB light source can avoid exposing the liquid crystal to UV light, which is inevitable when using conventional light sources such as cold cathode fluorescent lamps. Thus, according to another aspect of the present invention, there is provided an optical device including an RGB light source and the above-described optical component, wherein the phase of an incident optical signal from the RGB light source is modulated by the component when the optical device is operating.

[0157] According to another aspect of the present invention, there is provided a method for spatially modulating visible light or infrared light, comprising: i) providing an LCoS panel according to the present invention; ii) receiving visible light or infrared light incident on the surface of the LCoS panel; iii) applying a predetermined voltage to each of the individual electrodes of the LCoS panel to modulate the refractive index of the liquid crystal layer.

[0158] According to another aspect of the present invention, there is provided a method for manufacturing an LCoS panel, comprising at least the following steps: a) providing a first substrate having a first electrode with a two-dimensional array of individually electrically drivable pixels; b) depositing a preferred liquid crystal medium as disclosed herein on the first substrate; and c) mounting a second substrate having a second electrode on the liquid crystal material. A method including the above is provided.

[0159] It goes without saying for those skilled in the art that the liquid crystal mixture used for the present invention may also include compounds in which, for example, H, N, O, Cl and F are replaced by corresponding isotopes.

[0160] The compounds according to the invention can be synthesized by known and suitable reaction conditions for the reaction 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. Here, modifications that are known per se but not mentioned here can also be used. In particular, they can be prepared as described in the following reaction schemes or by analogous methods. Further methods for preparing the compounds of the invention can be adopted from the examples.

[0161] 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 those skilled in the art.

[0162] 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.

[0163] Table A shows the codes for the ring elements of the nucleus of the compounds, Table B lists the bridging units, and Table C lists the meanings of the symbols related to the left- and right-hand 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-hand end group, and the second hyphen and the code related to the right-hand end group. Table D shows the exemplary structures of the compounds together with their respective abbreviations.

[0164] Table A: Ring Element

Table A-1

Table A-2

Table A-3

[0165] Table B: Crosslinking Unit

Table B

[0166] Table C: End Group

Table C-1

Table C-2

[0167] Apart from the compounds represented by Formulae IV-2, I and ST-1, the mixtures according to the invention optionally contain one or more of the compounds 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, depending on the case, 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".)

[0168] Table D

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

[0169] Table E shows the chiral dopants preferably employed in the mixtures according to the invention. Table E

Table E-1

Table E-2

Table E-3

[0170] 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.

[0171] Example The invention is illustrated in detail by the following non-limiting examples. The following abbreviations and symbols are used: V0 Threshold voltage, capacitance at 20 °C [V], n e Anomalous refractive index at 20 °C and 589 nm, n o Ordinary refractive index at 20 °C and 589 nm, Δn Optical anisotropy at 20 °C and 589 nm, ε⊥ Dielectric permittivity perpendicular to the director at 20 °C and 1 kHz, ε|| Dielectric permittivity 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 Rotational viscosity at 20 °C [mPa·s], K1 Elastic constant, "spray" deformation at 20 °C [pN], K2 Elastic constant, "twist" deformation at 20 °C [pN], K3 Elastic constant, "bend" deformation at 20 °C [pN].

[0172] Unless explicitly stated otherwise, all concentrations in this application are given in weight percent units 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 given 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 the transition temperatures.

[0173] 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 apply 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 relates to the capacitance threshold (V0), also known as the Freedericks threshold, unless explicitly shown otherwise. In examples, the optical threshold may be shown for a relative contrast of 10% (V 10 ).

[0174] 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.

[0175] Unless otherwise indicated, the VHR is a commercially available device model LCM-1 (O0004) from TOYO Corporation, Japan, and is determined at 20 °C (VHR 20 ) and after 5 minutes in an oven at 100 °C (VHR 100 ). Unless more precisely indicated, the voltage used has a frequency within the range of 1 Hz to 60 Hz.

[0176] The stability against UV irradiation is investigated in a commercially available device "Suntest CPS+" from Heraeus, Germany, using a xenon lamp NXE1500B. The sealed test cells are irradiated for 2.0 hours without additional heating unless explicitly stated otherwise. The irradiation power in the wavelength range of 300 nm to 800 nm is 765 W / m 2 V. A UV "cut-off" filter with an edge wavelength of 310 nm is used to simulate the so-called window glass mode. 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 measurements.

[0177] 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 or, in some cases, the occurrence of the smectic phase at low temperatures, several sealed bottles containing approximately 1 g of material each are stored at one or more given temperatures, typically -10 °C, -20 °C, -30 °C, and / or -40 °C, and 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 at which no change was observed is noted as the respective LTS.

[0178] The ion density for calculating the resistivity is measured using a VHR test cell made of AL16301 polyimide (JSR Corp., Japan) with 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.

[0179] The transparency is measured using a Mettler Thermosystem FP900. The optical anisotropy (Δn) is measured using an Abbe refractometer H005 (with a sodium spectral lamp Na10, 589 nm, at 20 °C). The dielectric anisotropy (Δε) is measured using an LCR-Meter E4980A / Agilent (G005) at 20 °C (in an ε-parallel cell equipped with JALS 2096-R1). The threshold voltage (V0) is measured using an LCR-Meter E4980A / Agilent (G005) at 20 °C (in an ε-parallel cell equipped with JALS 2096-R1). The rotational viscosity (γ1) is measured using a TOYO LCM-2 (0002) at 20 °C (in a gamma1 negative cell equipped with JALS 2096-R1). The elastic constant (K1, spray) is measured using an LCR-Meter E4980A / Agilent (G005) at 20 °C (in an ε-parallel cell equipped with JALS 2096-R1). K3: The elastic constant (K3, bend) is measured using an LCR-Meter E4980A / Agilent (G005) at 20 °C (in an ε-parallel cell equipped with JALS 2096-R1).

[0180] 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 are described by the following acronyms: [Chemical formula]

[0181] The following nematic LC mixtures have the compositions and physical properties shown in the following table: Comparative Mixture CM1 [Table F-1]

[0182] Exemplary Mixture M2 [Table F-2]

[0183] Exemplary Mixture M3

Table F-3

[0184] Exemplary Mixture M4

Table F-4

[0185] Exemplary Mixture M5

Table F-5

[0186] Exemplary Mixture M6

Table F-6

[0187] The above exemplary mixture is filled into a test cell (d = 2.5 μm) with an inorganic alignment (SiO x ) layer or into an LCoS panel at 20 °C. The alignment is tested using crossed polarizers. The cell is further observed with a magnifying camera (×3). The device is tested under forced temperature and illumination (300 mW / cm 2 for 30 h, 460 nm LED). The occurrence of bubbles and darkening (mura) is avoided over the long term. The alignment is found to be vertical and stable. Further results regarding reliability are summarized in the following table.

[0188] Table 1. Results for the mixtures identified by number.

Table 1

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) Formula I 【Chemistry 1】 In the formula, R 11 and R 12 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 2】 and 【Chemistry 3】 and Z 1 is a single bond, -CH 2 CH 2 - or -(CO)O-, n independently represents 0 or 1; L 11 , L 12 , L 13 , L 14 represents independently H or methyl; b) Formula III 【Chemistry 4】 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 5】 -C≡C-, -CF 2 O-, -OCF 2 may each be replaced by -, -CH=CH-, -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, in each occurrence independently of one another, 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, n represents 0, 1 or 2; 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, and W represents O or S, and c) Formula IV 【Chemistry 6】 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, One or more compounds represented by 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. The liquid crystal medium has the formula IV-2 【Chemistry 7】 Where: Alkyl represents alkyl having 1 to 7 C atoms, and Alkoxy represents alkoxy having 1 to 5 C atoms, 5. The LCoS panel according to claim 1, comprising one or more compounds of formula IV selected from:

6. a) Formula I 【Chemistry 8】 In the formula, R 11 and R 12 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 9】 and 【Chemistry 10】 and Z 1 is a single bond, -CH 2 CH 2 - or -(CO)O-, n independently represents 0 or 1; L 11 , L 12 , L 13 , L 14 independently represent H or methyl; one or more compounds represented by b) Formula III 【Chemistry 11】 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 12】 -C≡C-, -CF 2 O-, -OCF 2 may each be replaced by -, -CH=CH-, -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, in each occurrence independently of one another, 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 and is preferably 1,4-cyclohexylene or 1,4-cyclohexenylene, n represents 0, 1 or 2; 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, and W represents O or S; one or more compounds represented by And c) Formula IV 【Chemistry 13】 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, One or more compounds represented by A liquid crystal medium comprising:

7. 7. The liquid-crystalline medium according to claim 6, The group represented by formula e): e) Formulas IIA, IIB, IIC, IID and IIE 【Chemistry 14】 In the formula, R 1A , R 1B , R 1C , and R 1D 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 15】 -C≡C-, -CF 2 O-, -OCF 2 The O atoms may be replaced by -, -OC-O- or -O-CO- in such a way that they are not directly linked to each other; R 2A , R 2B , R 2C , and R 2D 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 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; L 1 and L 2 are each independently F, Cl, CF 3 or CHF 2 represents; Y is H, F, Cl, 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-, R 1E 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 17】 -C≡C-, -CF 2 O-, -OCF 2 may be replaced by -, -OCO-O- or -O-CO- in such a way that the O atoms are not directly linked to each other; R 2E 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 18】 may be replaced by; p represents 0, 1, or 2; q represents 0 or 1, and v represents 1, 2, 3, 4, 5, or 6; The liquid crystal medium according to claim 1, further comprising one or more compounds selected from the group consisting of

8. 8. Liquid-crystalline medium according to claim 6, comprising the compound of the formulae T-1 to T-3: 【Chemistry 19】 In the formula, R 11 , R 12 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 20】 and Z 1 is a single bond, -CH 2 CH 2 -, -CH=CH-, -CF 2 O-, -OCF 2 -, -CH 2 O-, -OCH 2 -, -COO-, -OCO-, -C 2 F 4 -, -CF=CF- or -CH=CHCH 2 O-, L 11 , L 12 are H, F, and CH 3 where L 11 and L 12 does not mean that both are F, and L 13 is H or F, The liquid crystal medium according to claim 1, further comprising one or more compounds selected from the group consisting of

9. A liquid crystal medium according to any one of claims 6 to 8 for use in an LCoS panel.

10. 10. An LCoS panel according to any one of claims 1 to 5, wherein the liquid crystal medium is according to any one of claims 6 to 9.

11. A projection system, near-eye display, optical phase modulator or beam steering application comprising the LCoS panel according to any one of claims 1 to 5, a light source and a light directing element.

12. Use of a liquid crystal medium according to any one of claims 6 to 9 in LCoS panels, projection systems, near eye displays, optical phase modulators or beam steering applications.

13. Use of a liquid crystal medium according to any one of claims 6 to 9 for energy-saving LC displays.

14. A method for manufacturing the LCoS panel according to claim 1, comprising at least the following steps: a) providing a first substrate having a first electrode having a two-dimensional array of individually electrically addressable pixels; b) depositing on a first substrate a liquid crystal medium according to claim 6; and c) depositing a second substrate having a second electrode onto the liquid crystal material; The method comprising:

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