Reflection type liquid crystal panel

Abstract

The present invention relates to liquid crystal (LC) panels using liquid crystal (LC) media having negative dielectric anisotropy and to LC media contained therein. The disclosed liquid crystal media (LC media) have negative dielectric anisotropy and high optical anisotropy, and are particularly suitable for electro-optic displays including projection systems based on vertical alignment (VA) nematic panels.

Description

Field of the Invention

[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 to the liquid crystal medium contained therein.

[0002] The liquid crystal medium (LC medium) has negative dielectric anisotropy and very high optical anisotropy and is particularly suitable for electro-optical microdisplays or projection systems based on vertically aligned (VA) nematic panels. Background Art

[0003] LCoS panels are used as reflective matrix arrays for devices such as, for example, projection systems, near-eye displays or beam control applications. In the most common mode, the display modulates the polarization orientation (amplitude modulation) like most conventional LC displays. Some applications of LCoS utilize the controlled phase modulation of coherent light to control the spatial distribution of light beams, including image projection. Given new applications and light sources, the development of LCoS panels is useful for improvement.

[0004] An alignment layer is usually applied on the electrodes (if such electrodes exist) to bring it into contact with the liquid crystal medium and to induce an initial alignment of the liquid crystal molecules. The alignment layer in LCoS panels often consists of an inorganic alignment material, which is more heat-resistant than the polyimide layers mainly used in other liquid crystal panels for desktop or television applications, but the alignment strength of the inorganic material often decreases. The various alignment characteristics of these inorganic materials need to be carefully tested. For LCoS panels, a liquid crystal medium with high alignment characteristics on the inorganic alignment material is required. In addition, these devices usually need to have high light stability and a longer service life under high light intensity and temperature stress (e.g., a standard operating temperature of about 60 - 70 °C). Some applications also require a high temperature range (e.g., in outdoor devices and vehicles) and short response times.

[0005] Another problem observed in the prior art is that the use of conventional liquid crystal media in LCoS panels often results in defects (such as misalignment, white dots, color aberration, bubbles and dark areas) in the display due to the severe temperature and radiation during use. Therefore, it is necessary to provide a liquid crystal medium that can reduce display defects after continuous use. This means that they must be stable themselves and bond well with adjacent materials (such as the inorganic alignment layer).

[0006] Another problem observed in the prior art is that LC media for displays (including but not limited to LCoS-type displays) often exhibit high viscosity and thus long switching times.

[0007] In addition, there is a great demand for displays and LC media for such displays that can achieve high resistivity, while having a large operating temperature range, short response time, low threshold voltage, multiple gray levels, high contrast, high reliability after UV exposure, and high VHR values. Summary of the Invention

[0008] The object of the present invention is to provide a novel and suitable LC medium for devices that does not have the above-mentioned disadvantages or has them to a reduced extent.

[0009] Another object of the present invention is to provide an LCoS panel that does not have the above-mentioned disadvantages or has them only to a reduced extent, while the panel has low viscosity, high birefringence, negative dielectric anisotropy, high transmittance or reflectance, and high definition bright spots.

[0010] In particular, the object of the present invention is to provide an LC medium suitable for a phase modulation display. Among them, the delay of the optical signal is modulated pixel by pixel. The resulting reflected light can control the intensity by interference. Applications of small projectors are, for example, in the field of augmented reality applications in near-eye devices, head-up displays, automotive projection displays, or similar devices.

[0011] According to the present invention, these objects have been achieved by the materials and methods described in this application. In particular, it has been unexpectedly found that the above-mentioned advantageous effects can be achieved by using the liquid crystal host described below.

[0012] In one aspect, the present invention relates to an LCoS panel comprising an LC medium, which comprises

[0013] a) one or more compounds of formula I

[0014]

[0015] Wherein

[0016] R 11 and R 12 represent alkyl groups having 1 - 7 carbon atoms, alkoxy groups having 1 - 7 carbon atoms, or alkoxyalkyl, alkenyl, or alkenoxy groups having 2 - 7 carbon atoms, wherein, in addition, one or more CH 2 groups can each be independently replaced by substituted,

[0017] is

[0018] preferably

[0019]

[0020] Z 1 is a single bond, -CH 2 CH 2 -, or -(CO)O-, preferably a single bond,

[0021] n is independently 0 or 1,

[0022] L 11 、L 12 、L 13 、L 14 are independently H or methyl,

[0023] b) one or more compounds of formula III

[0024]

[0025] wherein

[0026] R 31 and R 32 each independently represent H, an alkyl or alkoxy group having 1 - 7 C atoms, wherein one or more CH 2 groups can each independently of one another be replaced by -C≡C-, -CF 2 O-, -OCF 2 -, -CH=CH-, -O-, -CO-O- or -O-CO- in such a way that the O atoms are not directly connected to each other, and wherein one or more H atoms can be replaced by halogen,

[0027] A 3 each independently represents 1,4-phenylene in each occurrence, wherein one or two CH groups can be replaced by N, or 1,4-cyclohexylene or 1,4-cyclohexenylene, wherein one or two non-adjacent CH 2 groups can be replaced by -O- or -S-,

[0028] wherein the group can be mono- or polysubstituted by halogen atoms, preferably 1,4-cyclohexylene or 1,4-cyclohexenylene,

[0029] n represents 0, 1 or 2,

[0030] Z 3 each independently represents -CF 2 O-, -OCF 2 -, -CH 2 O-, -OCH 2 -, -CH 2 -, -CH 2 CH 2-, -CH=CH-, -C≡C- or a single bond,

[0031] L 31 and L 32 each independently represents F, Cl, CF 3 or CHF 2 and

[0032] W represents O or S.

[0033] and

[0034] c) one or more compounds of formula IV

[0035]

[0036] wherein

[0037] R 41 represents an unsubstituted alkyl having 1 - 7 C atoms or an unsubstituted alkenyl having 2 - 7 C atoms, preferably n-alkyl, particularly preferably having 2, 3, 4 or 5 C atoms, and

[0038] R 42 represents an unsubstituted alkyl having 1 - 7 C atoms, an unsubstituted alkoxy having 1 - 6 C atoms (both preferably having 2 - 5 C atoms) or an unsubstituted alkenyl having 2 - 7 C atoms, preferably having 2, 3 or 4 C atoms,

[0039] wherein optionally and preferably, one or more compounds of formula IV are selected from formulae IV-1 to IV-4, more preferably IV-1 to IV-3, and most preferably the compound of formula IV-2,

[0040] preferably alone or in combination with any one of IV-1, IV-3 and IV-4, and most preferably in combination with IV-3:

[0041]

[0042] wherein

[0043] alkyl represents an alkyl having 1 to 7 C atoms, and

[0044] alkoxy represents an alkoxy having 1 to 5 C atoms.

[0045] The present invention also relates to a liquid crystal medium for an LCoS panel as described above.

[0046] The present invention also relates to a method for preparing an LC medium as described above, comprising the step of mixing one or more compounds of formulae I, III and IV, optionally with other LC compounds and / or additives.

[0047] The present invention also relates to a projection device, comprising an LCoS panel and a light guiding element according to the present invention. The light guiding element may be selected from a lens, a mirror, a semi-reflective mirror, a prism or the like.

[0048] The present invention also relates to the use of the liquid crystal medium according to the present invention in a display. The present invention also relates to an LC display of the IPS, FFS, UB-FFS, UBplus, VA or PS-VA type comprising the LC medium according to the present invention. The present invention also relates to the use of the 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 the LC medium according to the present invention.

[0049] The present invention also relates to an LC display of the VA or PSA type, comprising two substrates, at least one of which is transparent to light, provided with an electrode on each substrate or two electrodes provided only on one of the substrates, and an LC medium layer between the substrates, the LC medium comprising one or more polymerizable compounds and an LC component as described in the context, wherein the polymerizable compounds are polymerized between the substrates of the display.

[0050] The present invention also relates to a VA type LC display, comprising two opposite substrates, one substrate being transparent and one substrate being a silicon semiconductor backplane.

[0051] The present invention also relates to a method of manufacturing an LCoS panel as described in the context, comprising the steps of filling or otherwise providing the LC medium as described in the context between the substrates of the panel and sealing it.

[0052] Preferred embodiments are also disclosed in the dependent claims and can also be obtained from the description. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 BRIEF DESCRIPTION:

[0054] In Figure 1 a reflective spatial light modulator is provided, in particular an LCoS panel 100, which comprises a liquid crystal material 140 as defined in the present disclosure, sandwiched between a transparent glass layer 110 having a transparent electrode 120 and a pixelated mirror 150 and its mounting (not shown) mounted on a silicon CMOS backplane 160. The mirror is divided into a two-dimensional array of individually addressable pixels. The pre-alignment of the liquid crystal 140 is provided by alignment layers 131 and 132.

[0055] The display according to the present invention has two electrodes, preferably applied in the form of a transparent layer on one or both substrates. In a typical reflective display, a continuous transparent electrode is applied to the transparent substrate. The opposite electrode is formed as individually addressable pixels.

[0056] Surprisingly, it has been found that a liquid crystal medium according to the invention enables the realization of a display having a fast response time, a low threshold voltage and a high birefringence, as well as a high reliability when exposed to radiation and thermal stress.

[0057] In particular, the medium according to the invention is characterized by good alignment properties on various alignment materials, especially inorganic alignment materials.

[0058] The LC medium according to the invention exhibits the following advantageous properties when used in VA or FFS displays:

[0059] - Improved display transmittance,

[0060] - High clearing temperature,

[0061] - Sufficient stability to heat and / or UV,

[0062] - High voltage holding ratio,

[0063] - Relatively fast switching, and

[0064] - Good LTS.

[0065] The LC medium of the invention exhibits the following advantageous properties when used in reflective displays (including projection systems):

[0066] - High clearing temperature,

[0067] - Relatively fast switching,

[0068] - Sufficient stability to heat, light and / or UV, and

[0069] - Excellent alignment on inorganic alignment materials.

[0070] In particular, the liquid crystal medium according to the invention exhibits a favorable ratio γ 1 / K 1 of the rotational viscosity to the splay elastic constant. This helps to improve the switching behavior, especially at low driving voltages, which is useful for realizing energy-saving displays.

[0071] The necessary and optional components of the LC medium are disclosed in more detail below, which relate to the preferred embodiments of the medium and LC displays containing them.

[0072] The LCOS panel and the medium preferably further comprise:

[0073] d) 0.1% to 0.9% of one or more compounds of formula ST-1

[0074]

[0075] wherein

[0076] R ST represents H, an alkyl or alkoxy group having 1 - 15 C atoms, wherein furthermore, one or more CH 2 groups may each independently of one another be replaced by -C≡C-, -CF 2 O-, -OCF 2 -, -CH=CH-, -O-, -CO-O- or -O-CO- in such a way that the O atoms are not directly linked to one another, and wherein furthermore, one or more H atoms may be replaced by halogen,

[0077] in each occurrence, represents, identically or differently, or

[0078] Z ST each independently represents -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 -, -CF=CF-, -CH=CF-, -CF=CH-, -CH=CH-, -C≡C- or a single bond, and

[0079] p represents 0, 1 or 2.

[0080] In one embodiment of the invention, a liquid crystal medium is preferably used which further comprises one or more compounds selected from the group of formula e):

[0081] e) formulae IIA, IIB, IIC, IID and IIE,

[0082]

[0083]

[0084] wherein

[0085] R1A , R 1B , R 1C and R 1D each independently represent H, an alkyl group having 1 - 7 C atoms or an alkenyl group having 2 - 7 C atoms, each of which is unsubstituted or at least monosubstituted by a halogen, wherein one or more CH 2 groups may be replaced by -O-, -S-, -C≡C-, -CF 2 O-, -OCF 2 -, -OC-O- or -O-CO- in such a way that O atoms are not directly connected to each other;

[0086] R 2A , R 2B , R 2C and R 2D each independently represent H, an alkyl group having 1 - 7 C atoms or an alkenyl group having 2 - 7 C atoms, each of which is unsubstituted or at least monosubstituted by a halogen, wherein one or more CH 2 groups may be replaced by -O-, -S-, -C≡C-, -CF 2 O-, -OCF 2 -, -OC-O- or -O-CO- in such a way that O atoms are not directly connected to each other, preferably an alkoxy group having 1 - 6, more preferably 2 - 5 C atoms;

[0087] R 1E represents H, an alkyl group having 1 - 7 C atoms or an alkenyl group having 2 - 7 C atoms, each of which is unsubstituted or at least monosubstituted by a halogen, wherein one or more CH 2 groups may be replaced by -O-, -S-, -C≡C-, -CF 2 O-, -OCF 2 -, -OC-O- or -O-CO- in such a way that O atoms are not directly connected to each other;

[0088] R 2E represents an alkoxy group having 1 - 7 C atoms or an alkyl group or an alkenyl group having 2 - 7 C atoms, each of which is unsubstituted or at least monosubstituted by a halogen, wherein one or more CH 2 groups may be replaced by replaced;

[0089] L 1 and L 2 each independently represent F, Cl, CF3 or CHF 2 ,

[0090] Y represents H, F, Cl, CF 3 , CHF 2 or CH 3 ,

[0091] 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,

[0092] q represents 0 or 1, and

[0093] v represents 1, 2, 3, 4, 5 or 6.

[0094] In one embodiment of the present invention, a liquid crystal medium is preferred, wherein the medium comprises one or more compounds selected from the formulas T-1 to T-3:

[0095]

[0096]

[0097] wherein R 11 , R 12 represent an alkyl group having 1-7 C atoms, an alkoxy group having 1-7 C atoms or an alkoxyalkyl group, alkenyl group or alkenyloxy group having 2-7 carbon atoms, wherein, in addition, one or more CH 2 groups can each independently be

[0098] 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-,

[0099] L 11 、L 12 is H, F or CH 3 wherein L 11 and L 12 are not both F,

[0100] and

[0101] L 13 is H or F.

[0102] In formulas T-1 and T-2, preferably

[0103] R 11 is an n-alkyl or alkenyl having at most 7 C atoms, most preferably an n-alkyl having 1-5 C atoms, and

[0104] R 12 is an n-alkoxy or alkenyloxy having 1-6 C atoms, most preferably an n-alkoxy having 1-4 C atoms,

[0105] and in formula T-3, preferably

[0106] R 11 is an n-alkyl or alkenyl having at most 7 C atoms, most preferably an n-alkyl having 1-5 C atoms, and

[0107] R 12 is an n-alkyl or alkenyl having at most 7 C atoms, most preferably an n-alkyl having at most 5 C atoms.

[0108] The liquid crystal medium according to the invention preferably comprises one or more compounds of formula T-1, preferably selected from the compounds of formulas T-1a to T-1c, most preferably the compound of formula T-1a,

[0109]

[0110]

[0111] The liquid crystal medium according to the invention preferably comprises one or more compounds of formula T-2, preferably selected from the compounds of formulas T-2a to T-2e, preferably the compound of formula T-2a,

[0112]

[0113] wherein the groups occurring have the corresponding meanings given above for T-2.

[0114] The liquid crystal medium according to the present invention preferably contains one or more compounds of formula T-3, preferably selected from compounds of formulae T-3a to T-3c, preferably compounds of formula T-3a and / or T-3c, and most preferably a compound of formula T-3c,

[0115]

[0116] wherein the groups occurring have the respective meanings given above for T-3.

[0117] In a preferred embodiment of the present invention, the liquid crystal medium contains one or more compounds selected from compounds of formulae I-1 to I-3:

[0118]

[0119] wherein R 11 、R 12 represent an alkyl group having 1 to 7 carbon atoms, an alkoxy group having 1 to 7 carbon atoms or an alkoxyalkyl group, alkenyl group or alkenyloxy group having 2 to 7 carbon atoms, where, in addition, one or more CH 2 groups in these groups may each independently of one another be substituted,

[0120] 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-, preferably a single bond,

[0121] L 13 is H or F.

[0122] Preferred compounds of formulae IIA, IIB, IIC, IID and IIE are shown below:

[0123]

[0124]

[0125]

[0126]

[0127]

[0128]

[0129]

[0130]

[0131]

[0132]

[0133]

[0134]

[0135]

[0136]

[0137]

[0138] wherein the parameter a represents 1 or 2, alkyl and alkyl * each independently of one another represents a straight-chain alkyl group having 1-6 C atoms, and alkenyl represents a straight-chain alkenyl group having 2-6 C atoms, and (O) represents an oxygen atom or a single bond, preferably an oxygen atom. Alkenyl preferably represents 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 -.

[0139] Highly preferred compounds of formula IID are selected from the following sub-formulas:

[0140]

[0141]

[0142]

[0143]

[0144]

[0145]

[0146] wherein v represents 1, 2, 3, 4, 5 or 6.

[0147] In a preferred embodiment, the medium comprises one or more compounds of formula IID-10a

[0148]

[0149] wherein the groups and parameters occurring have the meanings given under formula IID above, and preferably R 2D represents

[0150] where r is 0, 1, 2, 3, 4, 5 or 6 and s is 1, 2 or 3.

[0151] In a preferred embodiment, the medium comprises one or more compounds of the following formula IIE:

[0152]

[0153]

[0154] wherein

[0155] m is 1, 2, 3 or 4, preferably 2 or 4.

[0156] More preferably, the medium according to the invention comprises one or more compounds of 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.

[0157] Very preferably, the medium according to the invention comprises one or more compounds of formula IIB-2

[0158]

[0159] where alkyl and alkyl * each independently of one another represent a straight-chain alkyl having 1-6 C atoms, and (O) represents an oxygen atom or a single bond, in particular the compounds IIB-2-1 and IIB-2-2:

[0160]

[0161] Preferably, the medium according to the invention comprises at least one compound of formula IIC-1,

[0162]

[0163] wherein alkyl and alkyl * have the above meanings, preferably in an amount of from 0.5% to 5% by weight, in particular from 1% to 3% by weight.

[0164] In particular, the medium comprises one or more compounds of formula IIA-2 selected from the following sub-formulas:

[0165]

[0166]

[0167] Alternatively, preferably, in addition to the compounds of formulas IIA-2-1 to IIA-2-5, the medium further comprises one or more compounds of formulas IIA-2a-1 to IIA-2a-5:

[0168]

[0169] In particular, the medium comprises one or more compounds of formula IIB-10 selected from the following sub-formulas:

[0170]

[0171] Alternatively, preferably, in addition to the compounds of formulas IIB-10-1 to IIB-10-5, the medium further comprises one or more compounds of formulas IIB-10a-1 to IIB-10a-5:

[0172]

[0173]

[0174] Very preferably, the medium according to the invention comprises one or more compounds of formula IIE, in particular compounds of formulas IIE-1-1 to IIE-1-8, and most preferably one or more compounds of formulas IIE-1-1-1 to IIE-1-1-4:

[0175]

[0176] The compound of formula III is preferably selected from the compounds of formulas III-1, III-2 and / or III-4

[0177]

[0178]

[0179] The groups occurring therein have the same meanings as given in formula III above, and preferably

[0180] R 31 and R 32 each independently of one another represent an alkyl or alkoxy group having 1 to 15 C atoms or an alkenyl group having 2 to 15 C atoms, more preferably, one or both of them represent an alkoxy group having 1 to 7 C atoms, and

[0181] L 31 and L 32 preferably represent F.

[0182] The liquid crystal medium according to the invention preferably comprises one, two or more compounds of formula III-2. In a preferred embodiment, the liquid crystal medium contains at least one compound of formula III-1 and at least one compound of formula III-2. In a further preferred embodiment, the liquid crystal medium contains at least one compound of formula III-2 and at least one compound of formula III-3.

[0183] Preferably, the compounds of formula III-1 are selected from the compounds of formulae III-1-1 to III-1-10, preferably the compound of formula III-1-6,

[0184]

[0185]

[0186]

[0187] wherein

[0188] alkyl and alkyl * each independently of one another represent a straight-chain alkyl group having 1 to 6 C atoms, alkenyl and alkenyl * each independently of one another represent a straight-chain alkenyl group having 2 to 6 C atoms, alkoxy and alkoxy * each independently of one another represent a straight-chain alkoxy group having 1 to 6 C atoms, and L 31 and L 32 each independently of one another represent F or Cl, preferably both are F.

[0189] Preferably, the compounds of formula III-2 are selected from the compounds of formulae III-2-1 to III-2-10, preferably the compound of formula III-2-6,

[0190]

[0191]

[0192] wherein

[0193] alkyl and alkyl * each independently of one another represent a straight-chain alkyl group having 1 to 6 C atoms, alkenyl and alkenyl * each independently of one another represent a straight-chain alkenyl group having 2 to 6 C atoms, alkoxy and alkoxy * each independently of one another represent a straight-chain alkoxy group having 1 to 6 C atoms, and L 31 and L 32 each independently of one another represent F or Cl, preferably both are F.

[0194] Optionally, the medium comprises one or more compounds of formula IIIA-1 and / or IIIA-2

[0195]

[0196] wherein L 31 and L 32 have the same meanings as given under formula III, (O) represents O or a single bond,

[0197] R IIIA represents an alkyl or alkenyl group having at most 7 C atoms, or the group Cy-C m H 2m+1 ,

[0198] m and n are the same or different and are 0, 1, 2, 3, 4, 5 or 6, preferably 1, 2 or 3, very preferably 1,

[0199] Cy represents an alicyclic group having 3, 4 or 5 ring atoms, which is optionally substituted with an alkyl or alkenyl group each having at most 3 C atoms, or with a halogen or CN, and preferably represents cyclopropyl, cyclobutyl, cyclopentyl or cyclopentenyl.

[0200] The compounds of formula IIIA-1 and / or IIIA-2 can be contained in the LC medium in place of or additionally to the compounds of formula III, preferably additionally.

[0201] Very preferred compounds of formula IIIA-1 and IIIA-2 are as follows:

[0202]

[0203]

[0204] wherein alkoxy represents a straight-chain alkoxy group having 1 to 6 C atoms, or alternatively represents –(CH 2 ) n F, where n is 2, 3, 4 or 5, preferably C2 H 4 F。

[0205] In a preferred embodiment of the present invention, the medium comprises one or more compounds of formula III-3

[0206]

[0207] wherein

[0208] R 31 、R 32 are the same or different and represent H, an alkyl or alkoxy group having 1-15 C atoms, wherein one or more CH 2 groups are optionally independently replaced by -C≡C-, -CF 2 O-, -OCF 2 -, -CH=CH-, -O-, -CO-O- or -O-CO- in such a way that the O atoms are not directly connected to each other, and wherein, additionally, one or more H atoms may be replaced by halogen.

[0209] The compounds of formula III-3 are preferably selected from the compounds of formulae III-3-1 to III-3-10:

[0210]

[0211]

[0212] wherein R 32 represents an alkyl group having 1-7 C atoms, preferably ethyl, n-propyl or n-butyl, or alternatively represents cyclopropylmethyl, cyclobutylmethyl or cyclopentylmethyl, or alternatively represents –(CH 2 ) n F, where n is 2, 3, 4 or 5, preferably C 2 H 4 F。

[0213] In a preferred embodiment of the present invention, the medium comprises one or more compounds of formulae III-4 to III-6, preferably formula III-5,

[0214]

[0215]

[0216] wherein the parameters have the meanings given above, R 31 preferably represents a straight-chain alkyl group having 1-7 C atoms and R 32 preferably represents an alkoxy group having 1-7 C atoms.

[0217] In a preferred embodiment, the medium according to the invention comprises one or more type III compounds selected from formulas III-7 to III-9, preferably formula III-8,

[0218]

[0219] wherein the parameters have the meanings given above, R 31 preferably represents a straight-chain alkyl group having 1-7 C atoms and R 32 preferably represents an alkoxy group derived from an alkane having 1-7 C atoms.

[0220] In a preferred embodiment, the medium comprises one or more type IV compounds,

[0221]

[0222] wherein

[0223] R 41 represents an unsubstituted alkyl group having 1-7 C atoms or an unsubstituted alkenyl group having 2-7 C atoms, preferably an n-alkyl group, particularly preferably having 2, 3, 4 or 5 C atoms, and

[0224] R 42 represents an unsubstituted alkyl group having 1-7 C atoms or an unsubstituted alkoxy group having 1-6 C atoms (both preferably having 2-5 C atoms), an unsubstituted alkenyl group having 2-7 C atoms, preferably having 2, 3 or 4 C atoms, more preferably vinyl or 1-propenyl and particularly preferably vinyl.

[0225] wherein the compounds of formula I are excluded from formula IV and its sub-formulas.

[0226] The type IV compounds are preferably selected from the compounds of formulas IV-1 to IV-4,

[0227]

[0228] wherein

[0229] alkyl and alkyl’ independently of one another represent an alkyl group having 1-7 C atoms, preferably having 2-5 C atoms,

[0230] alkenyl represents an alkenyl group having 2-5 C atoms, preferably having 2-4 C atoms, particularly preferably 2 C atoms,

[0231] alkenyl’ represents an alkenyl group having 2-5 C atoms, preferably having 2-4 C atoms, particularly preferably having 2-3 C atoms, and

[0232] Alkoxy represents an alkoxy group having 1 to 5 C atoms, preferably having 2 to 4 C atoms.

[0233] Preferably, one or more compounds of formula IV are selected from formula IV-1, IV-2 and IV-3, more preferably the compound of formula IV-2,

[0234] More preferably, IV-2 alone or in combination with any one of IV-1 and IV-3, most preferably in combination with IV-3.

[0235] Preferably, in addition to the compound of formula IV-2, the medium further contains one or more compounds selected from formula IV-1, IV-3 and IV-4.

[0236] Preferably, the medium comprises one or more compounds selected from formula IV-1-1 to IV-1-4

[0237]

[0238] Very preferably, the medium according to the invention comprises the compound of formula IV-1-1.

[0239] Very preferably, the medium according to the invention comprises one or more compounds of formula IV-1-1 to IV-1-6

[0240]

[0241]

[0242] In a preferred embodiment, the medium of the invention comprises one or more compounds of formula IV-3,

[0243]

[0244] wherein very preferably, alkyl represents an alkyl group having 1 to 7 C atoms, especially n-ethyl or n-propyl, very especially n-propyl, and alkenyl represents wherein m is 0, 1 or 2, preferably 0, and n is 0, 1 or 2, preferably 0 or 1,

[0245] especially selected from compounds of formula IV-3-1 to IV-3-6, very especially preferably the compound of formula IV-3-2:

[0246]

[0247]

[0248] In a preferred embodiment, in particular in addition to the compounds of formulae IV-3-1 to IV-3-6, the medium further comprises one or more compounds of formulae IV-3-7 to IV-3-9

[0249]

[0250] Preferably, the concentration of the compounds of formulae IV-3-7 to IV-3-9 in the medium according to the invention is less than 5% or less than 4% or less than 3%, very preferably from 0% to 1%, in particular 0%.

[0251] Very preferably, the medium according to the invention comprises one or more compounds of formula IV-3 and one or more compounds of formula IV-1, wherein the total concentration of the compounds of formula IV-1 is in the range from 1% to 30%.

[0252] Very preferably, the medium according to the invention comprises a compound of formula IV-4, in particular a compound selected from compounds of formulae IV-4-1 to IV-4-3, in particular a compound of formula IV-4-3

[0253]

[0254] In a preferred embodiment, the medium according to the invention comprises one or more compounds selected from compounds of formulae IA-1 to IA-18:

[0255]

[0256]

[0257]

[0258] wherein alkyl represents methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl or n-pentyl.

[0259] The LC medium according to the invention preferably comprises one or more compounds of formula IVa,

[0260]

[0261] wherein

[0262] R 41 and R 42 each independently of one another represent a straight-chain alkyl, alkoxy, alkenyl, alkoxyalkyl or alkenyloxy having at most 12 C atoms, and

[0263] represents

[0264] Z 4represents 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 -, -C 4 H 8 - or -CF=CF-.

[0265] Preferred compounds of formula IVa are shown below:

[0266]

[0267] wherein

[0268] alkyl and alkyl * each independently represent a straight-chain alkyl group having 1-6 C atoms.

[0269] The medium according to the invention preferably comprises at least one compound of formula IVa-1 and / or formula IVa-2, very preferably a compound of formula IVa-2, in particular a compound of formula IVa-2 wherein alkyl represents n-propyl and alkyl * represents methyl.

[0270] The proportion of the compound of formula IVa in the entire mixture is preferably less than 5% by weight, very preferably less than 2% by weight.

[0271] Preferably, the medium comprises one or more compounds of formula IVb-1 to IVb-3

[0272]

[0273] wherein

[0274] alkyl and alkyl * each independently represent a straight-chain alkyl group having 1-6 C atoms, and

[0275] alkenyl and alkenyl * each independently represent a straight-chain alkenyl group having 2-6 C atoms.

[0276] The proportion of the compounds of formula IV-1 to IV-3 in the entire mixture is preferably less than 3% by weight, in particular less than 2% by weight.

[0277] Among the compounds of formula IVb-1 to IVb-3, the compound of formula IVb-2 is particularly preferred.

[0278] Very particularly preferred biphenyls are

[0279]

[0280]

[0281] wherein alkyl * denotes an alkyl group having 1 - 6 C atoms and preferably denotes n - propyl or n - butyl. The medium according to the invention particularly preferably comprises one or more compounds of formula IVb - 1 - 1 and / or IVb - 2 - 3.

[0282] In the compound of formula IVb - 1 - 1, alkyl * preferably denotes propyl, butyl and pentyl, and most preferably denotes propyl.

[0283] In a preferred embodiment, the medium according to the invention comprises one or more compounds of formula V

[0284]

[0285] wherein

[0286] R 51 、R 52 denote an alkyl group having 1 - 7 C atoms, an alkoxy group having 1 - 7 C atoms or an alkoxyalkyl group, alkenyl group or alkenyloxy group having 2 - 7 C atoms,

[0287] denotes

[0288] denotes

[0289] Z 51 、Z 52 each independently of one another denote - CH 2 - CH 2 -、- CH 2 - O -、- CH=CH -、- C≡C -、- COO - or a single bond, and

[0290] n is 1 or 2.

[0291] The compounds of formula V are preferably selected from the compounds of formulae V - 1 to V - 14:

[0292]

[0293]

[0294] wherein R 51 and R52 Has the meaning as defined above for formula V.

[0295] R 51 and R 52 Preferably each independently represents a straight-chain alkyl group having 1-7 C atoms or an alkenyl group having 2-7 C atoms.

[0296] The preferred medium comprises one or more compounds of formulae V-1, V-3, V-4, V-6, V-7, V-10, V-11, V-12 and / or V-14.

[0297] In a preferred embodiment, the medium according to the invention comprises one or more compounds of formula Vb

[0298]

[0299] wherein

[0300] R 51 、R 52 represent an alkyl group having 1-7 C atoms, an alkoxy group having 1-7 C atoms or an alkoxyalkyl group, alkenyl group or alkenyloxy group having 2-7 C atoms,

[0301] represents

[0302] represents

[0303] Z 51 、Z 52 each independently represents -CH 2 -CH 2 -、-CH 2 -O-、-CH=CH-、-C≡C-、-COO- or a single bond, and

[0304] n is 2.

[0305] The compounds of formula Vb are preferably selected from the compounds of formulae Vb-1 to Vb-2:

[0306]

[0307] In a preferred embodiment of the invention, the medium further comprises one or more compounds of formula VI

[0308]

[0309] wherein, R 6 and R 62 have the meanings of R as defined in claim 1 2Athe meaning of, and R 62 alternatively represents F, Cl, CF 3 or OCF 3 , 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 represents F, and compounds of excluded subclasses IIC and IIE are excluded.

[0310] Compounds of formula VI are preferably selected from formulae VI-1 to VI-20, especially from formulae VI-1, VI-2, IV-4, VI-14, VI-19 and VI-20:

[0311]

[0312]

[0313]

[0314] where R 6 represents a straight-chain alkyl or alkoxy group having 1-6 C atoms, (O) represents -O- or a single bond, m is 0, 1, 2, 3, 4, 5 or 6, and n is 0, 1, 2, 3 or 4.

[0315] R 6 preferably represents methyl, ethyl, propyl, butyl, pentyl, hexyl, methoxy, ethoxy, propoxy, butoxy or pentyloxy.

[0316] Particularly preferred are the compounds of formulae VI-1, VI-2, VI-4, VI-19 and VI-20.

[0317] In a preferred embodiment of the present invention, the medium further comprises one or more compounds of formula VIA

[0318]

[0319] where R 6 and R 62 have the meaning of R as defined in claim 1 2A the meaning of, and R 62 alternatively represents F, Cl, CF 3 or OCF 3 , 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

[0320] Z 61 and Z 62 independently represent a single bond, -CH 2 -CH 2 -, -CH 2 -O-, -CH=CH-, -C≡C-, -COO- or -CF 2 -O- but Z 61 ≠Z 62 .

[0321] Very preferably, the medium according to the invention comprises a compound of formula VIA-1 and / or formula X

[0322]

[0323] where 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 a particularly preferred embodiment, R 6 represents n-propyl and m represents 2.

[0324] In a preferred embodiment of the invention, the medium further comprises one or more compounds of formula VII-1 to VII-9

[0325]

[0326]

[0327] where

[0328] R 7 represents a straight-chain alkyl or alkoxy group having 1-6 C atoms, or a straight-chain alkenyl group having 2-6 C atoms, and

[0329] w is an integer from 1 to 6.

[0330] Particularly preferably, a mixture comprising at least one compound of formula VII-9 is included.

[0331] A further preferred embodiment is as follows:

[0332] a) The liquid crystal medium contains at least one compound of formulae Z-1 to Z-8,

[0333]

[0334]

[0335] wherein R has the meaning of R in formula IIA 2A and alkyl represents a straight-chain alkyl having 1 to 6 C atoms.

[0336] In a preferred embodiment, the liquid crystal mixture according to the invention contains at least one compound of formula Z-8.

[0337] b) The preferred liquid crystal medium according to the invention contains one or more substances containing a tetrahydronaphthyl or naphthyl unit, such as compounds of formulae N-1 to N-5,

[0338]

[0339]

[0340] wherein R 1N and R 2N each independently of one another have the meaning given above for R 2A and preferably represent a straight-chain alkyl, a straight-chain alkoxy or a straight-chain alkenyl, and

[0341] Z 1 and Z 2 each independently of one another represent -C 2 H 4 -, -CH=CH-, -(CH 2 ) 4 -, -(CH 2 ) 3 O-, -O(CH 2 ) 3 -, -CH=CHCH 2 CH 2 -, -CH 2 CH 2 CH=CH-, -CH 2 O-, -OCH 2 -, -COO-, -OCO-, -C 2 F 4 -, -CF=CF-, -CF=CH-, -CH=CF-, -CF 2 O-, -OCF 2 -, -CH 2 - or a single bond.

[0342] c) The preferred mixture comprises one or more compounds selected from difluorodibenzochroman compounds of formula BC, chromans of formula CR, and fluorophenanthrene compounds of formula PH-1 and PH-2,

[0343]

[0344]

[0345] wherein R B1 , R B2 , R CR1 , R CR2 , R 1 , R 2 each independently of one another has the meaning of R 2A . c is 0, 1 or 2. R 1 and R 2 preferably independently of one another represent an alkyl or alkoxy group having 1 to 6 C atoms.

[0346] Particularly preferred compounds of formula BC and CR are compounds BC-1 to BC-7 and CR-1 to CR-5,

[0347]

[0348]

[0349] wherein

[0350] alkyl and alkyl * each independently of one another represent a straight-chain alkyl group having 1 to 6 C atoms, and

[0351] alkenyl and alkenyl * each independently of one another represent a straight-chain alkenyl group having 2 to 6 C atoms.

[0352] Very particularly preferably, the mixture comprises one, two or three compounds of formula BC-2, BF-1 and / or BF-2.

[0353] d) The preferred mixture comprises one or more indane compounds of formula In,

[0354]

[0355] wherein

[0356] R 11 , R 12 and R 13 each independently of one another represent a straight-chain alkyl, alkoxy, alkoxyalkyl or alkenyl group having 1 to 6 C atoms.

[0357] R 12and R 13 Alternatively represents a halogen, preferably F,

[0358] represents

[0359]

[0360] i represents 0, 1 or 2.

[0361] Preferred In compounds of the formula are the compounds of the formulae In-1 to In-16 described below:

[0362]

[0363]

[0364]

[0365] wherein R 11 has one of the meanings given above for R in formula IIA 2A One of the meanings given above for R in formula IIA

[0366] Particularly preferred are the compounds of the formulae In-1, In-2, In-3 and In-4.

[0367] e) The preferred mixture additionally comprises one or more compounds of the formulae L-1 to L-11,

[0368]

[0369]

[0370] wherein

[0371] R, R 1 and R 2 each independently of one another have the meanings given above for R in formula IIA 2A and alkyl represents an alkyl group having 1-6 C atoms. The parameter s represents 1 or 2.

[0372] The compounds of the formulae L-1 to L-11 are preferably used in a concentration of 5-15% by weight, in particular 5-12% by weight and very particularly preferably 8-10% by weight.

[0373] f) The preferred mixture additionally comprises one or more compounds of the formula IIA-Y

[0374]

[0375] wherein R 11 and R 12 have one of the meanings given above for R in formula IIA 2A and L1 and L 2 independently represent F or Cl, the same or different, and L 3 represents H or CH 3 .

[0376] The preferred compounds of formula IIA-Y are selected from the following sub-formulas

[0377]

[0378]

[0379]

[0380] wherein, alkyl and alkyl * each independently represent a straight-chain alkyl group having 1-6 C atoms, alkoxy and alkoxy * represent a straight-chain alkoxy group having 1-6 C atoms, alkenyl and alkenyl * each independently represent a straight-chain alkenyl group having 2-6 C atoms. Alkenyl and alkenyl * preferably represent 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 -. L 1 and L 2 independently represent F or Cl, the same or different, and L 3 represents H or CH 3 .

[0381] Particularly preferred compounds of formula IIA-Y are selected from the following sub-formulas:

[0382]

[0383] wherein alkoxy and alkoxy * have the meanings defined above and preferably represent methoxy, ethoxy, n-propoxy, n-butoxy or n-pentyloxy.

[0384] g) The medium additionally comprises one or more compounds selected from the compounds of formulae P-1 to P-4:

[0385]

[0386] wherein

[0387] R P represents a straight-chain alkyl or alkoxy having 1-6 C atoms or an alkenyl having 2-6 C atoms, preferably an alkyl, each of which is unsubstituted or at least monosubstituted by a halogen, wherein one or more CH 2 groups can be replaced by -O-, -S-, -C≡C-, -CF 2 O-, -OCF 2 -, -OC-O- or -O-CO- in such a way that the O atoms are not directly connected to each other;

[0388] X P represents a straight-chain alkyl having 1-6 C atoms, F, Cl, CF 3 -, OCF 2 H, OCF 3 -, OCHFCF 3 -, OCF 2 CHFCF 3 -, OCH=CF 2 , preferably F, OCF 3 or CF 3 , CH 3 ,

[0389] L P1 、L P2 and L P3 each independently represent H or F, and

[0390] L P4 represents H or CH 3 , preferably H.

[0391] Preferred compounds of formulae P1 to P4 are listed below:

[0392]

[0393]

[0394] wherein

[0395] L P represents H or CH 3 ;

[0396] R Phas the meaning given above. Preferably, R P represents alkyl, cycloalkyl, cycloalkylalkyl or alkenyl, especially ethyl, propyl, butyl, pentyl, cyclopropyl, cyclopentyl, 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 -, alkyl represents a straight-chain alkyl having 1-6 carbon atoms.

[0397] The compound of formula P-1 has a stabilizing property for the liquid crystal medium. In a preferred embodiment, the medium according to the present invention comprises at least one compound of formula P-1, more preferably a compound of formula P-1a, preferably in an amount of 0.1-5% by weight, more preferably 0.4-2.5% by weight.

[0398] Preferably, the liquid crystal medium according to the present invention comprises one or more compounds of formula H

[0399]

[0400] wherein

[0401] A represents a q-valent aliphatic, aromatic or heteroaromatic hydrocarbon group having 1-40 C atoms, preferably 6-30 C atoms; or a single bond when q = 2;

[0402] Sp represents a spacer group or a single bond;

[0403] R S represents H, an alkyl having 1-12 C atoms or an alkenyl having 2-12 C atoms;

[0404] Z S represents -O-, -C(O)O-, -(CH 2 ) z - or -(CH 2 ) z O- or a single bond; preferably -C(O)O-,

[0405] HA represents

[0406] R H represents H, O · , CH 3 , OH or OR S , preferably H or O · ;

[0407] R S1 , R S2 , R S3 and R S4 are the same or different and represent an alkyl group having 1 - 6 C atoms, preferably having 1 - 3 C atoms, very preferably CH 3 ;

[0408] G represents H or R S or the group Z S -HA;

[0409] z is an integer from 1 - 6; and

[0410] q is 1, 2, 3 or 4, preferably 2.

[0411] In formula H, A preferably represents an aromatic or heteroaromatic hydrocarbon group having 4 - 40 C atoms, which contains one, two, three or four aromatic rings (including fused rings which may be directly connected or connected by an alkylene linking group having 1 - 12 C atoms), wherein one or more H atoms are optionally replaced by an alkyl or alkoxy group having 1 - 6 C atoms or an alkenyl group having 2 - 6 C atoms, or by CN, CF 3 or a halogen, and wherein one or more CH 2 groups may each independently of one another be replaced by -O-, -S-, -NH-, -N(C 1 -C 4 -alkyl)-, -CO-, -CO - O-, -O - CO-, -O - CO - O-, -CH = CH- or -C≡C- in such a way that O or S atoms are not directly connected to each other.

[0412] Preferred aliphatic groups are alkylene, cycloalkylene, more preferably -(CHR S5 ) s -, where R S5 is H or an alkyl group having 1 - 5 C atoms and s is an integer from 1 - 20.

[0413] Preferred aryl groups are phenyl, naphthyl, anthracenyl, biphenyl, m - terphenyl, p - terphenyl and (phenylalkyl)phenyl, where the alkyl is a straight - chain alkyl having 1 - 12 C atoms.

[0414] Compounds of formula H are described in EP 3354710 A1 and EP 3354709 A1.

[0415] The preferred use range of the compound of formula H is 0.1 to 0.3% (by weight).

[0416] In a preferred embodiment, the medium comprises one or more compounds of formula H selected from compounds of formula H-A

[0417]

[0418] wherein

[0419] A a represents an alkylene group having 2 to 12 carbon atoms, wherein one or two CH 2 groups may each be replaced by 1,4-cyclohexylene, and

[0420] R H represents H or O · .

[0421] Group A a preferably represents

[0422]

[0423] -(CH 2 -) 2 、-(CH 2 -) 3 、-(CH 2 -) 4 、-(CH 2 -) 5 、-(CH 2 -) 6 、-(CH 2 -) 7 、-(CH 2 -) 8 , namely ethane-1,2-diyl, propane-1,3-diyl, butane-1,4-diyl, pentane-1,5-diyl, hexane-1,6-diyl, heptane-1,7-diyl, octane-1,8-diyl,

[0424]

[0425]

[0426] wherein

[0427] S 11 represents an alkylene group having 1 to 20 C atoms,

[0428] The compounds of formula H are preferably selected from compounds of formula H-1 to H-12:

[0429]

[0430]

[0431]

[0432]

[0433] wherein R H has the meaning given above and preferably represents H or O · and

[0434] q is an integer from 0 to 12, preferably 2, 4, 6, 8 or 10,

[0435] n is an integer from 0 to 12, preferably 5, 6, 7, 8 or 9, very preferably 7, and

[0436] Sp represents a spacer group, preferably an alkylene group having 1 to 12 C atoms, wherein one or more non-adjacent -CH 2 - groups may be replaced by -O-, and

[0437] R S is the same or different each time it appears, preferably the same, and represents H or an alkyl group having 1 to 6 C atoms.

[0438] Preferred compounds of formula H-10 are selected from compounds of formula H-10-1:

[0439]

[0440] wherein 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, very preferably 7.

[0441] Preferred compounds of formula H-11 are selected from compounds of formula H-11-1:

[0442]

[0443] wherein R H has the meaning given above and preferably represents H or O · and

[0444] n2 is the same or different each time it appears, preferably the same, and is an integer from 1 to 12, preferably 2, 3, 4, 5 or 6, very preferably 3, and R S is the same or different each time it appears, preferably the same, and represents H or an alkyl group having 1 to 6 C atoms, preferably n-butyl.

[0445] The preferred compound of formula H-12 is selected from the compound of formula H-12-1:

[0446]

[0447] wherein R H and R S and Sp have the meanings given above, and preferably R H represents H or O · and

[0448] n is an integer from 0 to 12, preferably 5, 6, 7, 8 or 9, very preferably 7.

[0449] The preferred stabilizer H is as follows:

[0450]

[0451]

[0452] Preferably, the medium according to the invention comprises a compound selected from formulas ST-1 to ST-13:

[0453]

[0454]

[0455]

[0456] wherein

[0457] R ST represents H, an alkyl or alkoxy group having 1 to 15 carbon atoms, wherein in addition, one or more CH 2 groups may each independently of one another be replaced by -C≡C-, -CF 2 O-, -OCF 2 -, -CH=CH-, -O-, -CO-O-, -O-CO- in such a way that the O atoms are not directly connected to each other, and wherein furthermore, one or more H atoms may be replaced by halogen, preferably R ST represents an alkyl group having 1 to 7 carbon atoms or cyclopentyl,

[0458] each occurring, identically or differently, represents

[0459] Z ST each independently of one another represents -CO-O-, -O-CO-, -CF 2 O-, -OCF 2 -, -CH2 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 -, -CF=CF-, -CH=CF-, -CF=CH-, -CH=CH-, -C≡C- or a single bond,

[0460] L 1 and L 2 each independently of one another represents F, Cl, CH 3 , CF 3 or CHF 2 ,

[0461] p represents 0, 1 or 2,

[0462] q represents 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10.

[0463] In the compounds of formula ST, compounds of formula ST-1 and ST-3 are particularly preferred, and in particular:

[0464]

[0465] where n = 1, 2, 3, 4, 5, 6 or 7, preferably n = 3

[0466]

[0467] where n = 1, 2, 3, 4, 5, 6 or 7, preferably n = 1

[0468] or 7

[0469]

[0470] where n = 1, 2, 3, 4, 5, 6 or 7, preferably n = 3

[0471]

[0472] A very particularly preferred mixture according to the invention comprises one or more compounds selected from the compounds of formulae ST-1a, ST-1b-1 and ST-1c-1:

[0473]

[0474]

[0475] In the liquid crystal mixture according to the present invention, the compounds of formulas ST-1 to ST-12 are each preferably present in an amount of 0.1-0.5% based on the mixture.

[0476] However, based on the mixture of the present invention, the total proportion of the compounds of formulas ST-1 to ST-12 should not exceed 2%.

[0477] The medium according to the present invention preferably has negative dielectric anisotropy.

[0478] Definition

[0479] As used herein, the term "reliability" means the quality of the performance of a display over a period of time and under different stress loads, such as light load, temperature, humidity, voltage, and includes display defects such as image sticking (surface and line image sticking), color mura, non-uniformity (yogore), etc., which are known to those skilled in the art of LC displays. As a standard parameter for classifying reliability, the voltage holding ratio (VHR) value is usually used, which is a measure of the amount of voltage maintained constant in a test display. Among other factors, a high VHR is a prerequisite for high reliability of an LC medium.

[0480] As used herein, the terms "active layer" and "switchable layer" denote, in an electro-optical display, for example in an LC display, a layer containing one or more molecules having structural and optical anisotropy (such as LC molecules), which change their orientation when subjected to an external stimulus such as an electric or magnetic field, which results in a change in the transmittance of the layer for polarized or non-polarized light.

[0481] Unless otherwise specified, as used herein, the term "liquid crystal display" refers to an information display based on switchable liquid crystals. It includes backlit and reflective displays for direct or indirect viewing, for virtual reality or augmented reality systems or projection systems. The size ranges from microdisplays to large screens. Addressing can be achieved in the following ways: LC displays include simple electrodes on a substrate, a thin film transistor array having electrodes for each pixel, or a structured silicon semiconductor as a backplane, with the latter being preferred.

[0482] As used herein, the terms "optically active" and "chiral" are synonyms for materials that are capable of inducing a helical pitch in a nematic host material, also known as "chiral dopants".

[0483] Throughout the patent application, the 1,4-cyclohexylene ring and the 1,4-phenylene ring are described as follows:

[0484]

[0485] The cyclohexylene ring is a trans-1,4-cyclohexylene ring.

[0486] In the context, represents a trans-1,4-cyclohexylene ring.

[0487] In the group the single bond shown between two ring atoms can be attached to any free position of the benzene ring.

[0488] "Organic group" in the context means a carbon group or a hydrocarbon group.

[0489] "Carbon group" means a monovalent or polyvalent organic group containing at least one carbon atom, where the group does not contain other atoms (e.g., -C≡C-) or optionally contains one or more other atoms, such as N, O, S, B, P, Si, Se, As, Te or Ge (e.g., carbonyl, etc.). The term "hydrocarbon group" means 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.

[0490] "Halogen" means F, Cl, Br or I, preferably F or Cl.

[0491] -CO-, -C(=O)- and -C(O)- represent a carbonyl group, i.e.,

[0492] The carbon group or hydrocarbon group can be a saturated or unsaturated group. Unsaturated groups are, for example, aryl, alkenyl or alkynyl groups. The carbon group or hydrocarbon group having more than 3 C atoms can be straight-chain, branched and / or cyclic and can also contain spiro linkages or fused rings.

[0493] The terms "alkyl", "aryl", "heteroaryl", etc. also include polyvalent groups, such as alkylene, arylene, heteroarylene, etc.

[0494] The term "aryl" means an aromatic carbon group or a group derived therefrom. The term "heteroaryl" means an "aryl" as defined above that contains one or more heteroatoms (preferably selected from N, O, S, Se, Te, Si and Ge).

[0495] In this text, the alkyl is straight-chain or branched and has 1 to 15 C atoms, preferably straight-chain and, unless otherwise stated, has 1, 2, 3, 4, 5, 6 or 7 C atoms, and is thus preferably methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl or n-heptyl.

[0496] In the present text, the branched alkyl group is an alkyl group having secondary and / or tertiary carbon atoms, 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.

[0497] In the present text, the cycloalkyl group refers to an alicyclic group or an alkyl group in which a methylene group is replaced by an alicyclic group (i.e., cycloalkylalkyl or alkylcycloalkylalkyl), which may be saturated or partially unsaturated, and preferably represents cyclopropyl, methylcyclopropyl, cyclobutyl, methylcyclobutyl, cyclopentyl, methylcyclopentyl, cyclopent-1-enyl, cyclopropylmethyl, cyclopropylethyl, cyclobutylmethyl, cyclobutylethyl, cyclopentylmethyl, cyclopentylethyl, cyclopent-1-enylmethyl.

[0498] In the present text, the alkoxy group is straight-chain or branched and contains 1 to 15 C atoms. It is preferably straight-chain and, unless otherwise stated, has 1, 2, 3, 4, 5, 6 or 7 C atoms, and is thus preferably methoxy, ethoxy, n-propoxy, n-butoxy, n-pentyloxy, n-hexyloxy or n-heptyloxy.

[0499] In the present text, the alkenyl group is preferably an alkenyl group having 2 to 15 C 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 C 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. If the two C atoms of the C═C double bond are substituted, the alkenyl group can be in the form of E and / or Z isomers (trans / cis). Generally, the corresponding E isomer is preferred. Among the alkenyl groups, prop-2-enyl, but-2- and but-3-enyl, pent-3- and pent-4-enyl are particularly preferred.

[0500] In the present text, the alkynyl group refers to an alkynyl group having 2 to 15 C atoms, which is straight-chain or branched and contains at least one C≡C triple bond. Preferred are 1- and 2-propynyl and 1-, 2- and 3-butynyl.

[0501] The preferred carbon-based and hydrocarbon-based groups are optionally substituted, straight-chain, branched-chain or cyclic alkyl, alkenyl, alkynyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy and alkoxycarbonyloxy groups having 1 to 40, preferably 1 to 20, very preferably 1 to 12 carbon atoms, optionally substituted aryl or aryloxy groups having 5 to 30, preferably 6 to 25 carbon atoms, or optionally substituted alkylaryl, aralkyl, alkylaryloxy, arylalkyloxy, arylcarbonyl, aryloxycarbonyl, arylcarbonyloxy and aryloxycarbonyloxy groups having 5 to 30, preferably 6 to 25 carbon atoms, wherein one or more carbon atoms may also be replaced by heteroatoms (preferably selected from N, O, S, Se, Te, Si and Ge).

[0502] Even more preferred carbon-based and hydrocarbon-based 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 alkyl-dienyl, C 4 -C 20 poly-alkenyl, C 6 -C 20 cycloalkyl, C 4 -C 15 cycloalkenyl, C 6 -C 30 aryl, C 6 -C 30 alkylaryl, C 6 -C 30 aralkyl, C 6 -C 30 alkylaryloxy, C 6 -C 30 arylalkyloxy, C 2 -C 30 heteroaryl, C 2 -C 30 heteroaryloxy.

[0503] 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 heteroaryl.

[0504] Further preferred carbon-based and hydrocarbon-based groups are straight-chain, branched-chain or cyclic alkyl groups having 1 to 20, preferably 1 to 12 C atoms, which are unsubstituted or mono- or poly-substituted by F, Cl, Br, I or CN, and where one or more non-adjacent CH 2 groups may each independently of one another be replaced by -C(R x )=C(R x )-, -C≡C-, -N(R x )-, -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O- in such a way that the O and / or S atoms are not directly linked to one another.

[0505] R x preferably represents H, F, Cl, CN, a straight-chain, branched-chain or cyclic alkyl chain having 1 to 25 C atoms, where additionally 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 represents 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.

[0506] Preferred alkyl groups are for example methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, 2-methylbutyl, n-pentyl, sec-pentyl, cyclopentyl, n-hexyl, cyclohexyl, 2-ethylhexyl, n-heptyl, cycloheptyl, n-octyl, cyclooctyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, trifluoromethyl, perfluorobutyl, 2,2,2-trifluoroethyl, perfluorooctyl, perfluorohexyl, etc.

[0507] Preferred alkenyl groups are for example vinyl, propenyl, butenyl, pentenyl, cyclopentenyl, hexenyl, cyclohexenyl, heptenyl, cycloheptenyl, octenyl, cyclooctenyl, etc.

[0508] Preferred alkynyl groups are for example ethynyl, propynyl, butynyl, pentynyl, hexynyl, octynyl, etc.

[0509] Preferred alkoxy groups are for example methoxy, ethoxy, 2-methoxyethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, sec-butoxy, tert-butoxy, 2-methylbutoxy, n-pentyloxy, n-hexyloxy, n-heptyloxy, n-octyloxy, n-nonyloxy, n-decyloxy, n-undecyloxy, n-dodecyloxy, etc.

[0510] Preferred amino groups are for example dimethylamino, methylamino, methylphenylamino, phenylamino, etc.

[0511] Aryl groups and heteroaryl groups can be monocyclic or polycyclic, i.e., they can contain one ring (e.g., phenyl) or two or more rings, which can also be fused (e.g., naphthyl) or covalently bonded (e.g., biphenyl), or contain a combination of fused and linked rings. Heteroaryl contains one or more heteroatoms, preferably selected from O, N, S, and Se.

[0512] Particularly preferred are mono-, bi- or tricyclic aryls having 6 - 25 C atoms and mono-, bi- or tricyclic heteroaryls having 5 - 25 ring atoms, which optionally contain fused rings and are optionally substituted. Further preferred are 5-, 6- or 7-membered aryl and heteroaryl groups, wherein 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 connected to each other.

[0513] Preferred aryl groups are, for example, phenyl, biphenyl, terphenyl, [1,1':3',1"]-terphenyl-2'-yl, naphthyl, anthracenyl, binaphthyl, phenanthryl, 9,10-dihydro-phenanthryl, pyrene, dihydropyrene, picene, tetracene, pentacene, benzopyrene, fluorene, indene, indenofluorene, spirobifluorene groups, etc.

[0514] Preferred heteroaryl groups are, 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, naphthimidazole, phenanthrimidazole, pyridineimidazole, pyrazineimidazole, quinoxalineimidazole, benzoxazole, naphthoxazole, anthraoxazole, phenanthroxazole, 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, thiophene[2,3b]thiophene, thiophene[3,2b]thiophene, dithienothiophene, isobenzothiophene, dibenzothiophene, benzothiophene, benzothiadiazolethiophene, or combinations of these groups.

[0515] The aryl and heteroaryl groups mentioned in the context may also be substituted by alkyl, alkoxy, thioalkyl, fluorine, fluoroalkyl or other aryl or heteroaryl groups.

[0516] (Non-aromatic) alicyclic groups and heterocyclic groups include both saturated rings, i.e., rings containing only single bonds, and partially unsaturated rings, i.e., those that may also contain multiple bonds. Heterocycles contain one or more heteroatoms, preferably selected from Si, O, N, S and Se.

[0517] (Non-aromatic) alicyclic groups and heterocyclic groups may be monocyclic, i.e., containing only one ring (e.g., cyclohexane), or polycyclic, i.e., containing multiple rings (e.g., decalin or bicyclooctane). Saturated groups are particularly preferred. Also preferred are mono-, bi- or tricyclic groups having 5-25 ring atoms, which optionally contain fused rings and are optionally substituted. Further preferred are 5-, 6-, 7- or 8-membered carbocyclic groups, wherein additionally, 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-.

[0518] Preferred alicyclic groups and heterocyclic groups are, for example, 5-membered groups such as cyclopentane, tetrahydrofuran, tetrahydrothiophene, pyrrolidine; 6-membered groups such as cyclohexane, silinane, cyclohexene, tetrahydropyran, tetrahydrothiopyran, 1,3-dioxane, 1,3-dithiane, piperidine; 7-membered groups such as cycloheptane; and fused groups such as tetralin, decalin, 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.

[0519] Preferred substituents are, for example, solubility promoting groups such as alkyl or alkoxy; electron-withdrawing groups such as fluorine, nitro or nitrile; or substituents for increasing the glass transition temperature (Tg) of the polymer, especially bulky groups such as tert-butyl or optionally substituted aryl.

[0520] Preferred substituents, also referred to hereinafter 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, a straight-chain or branched-chain alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy group having 1 to 25 carbon atoms, wherein one or more H atoms may optionally be replaced by F or Cl, an optionally substituted silyl group having 1 to 20 Si atoms, or an optionally substituted aryl group having 6 to 25, preferably 6 to 15 carbon atoms.

[0521] wherein R x represents H, F, Cl, CN, or a straight-chain, branched-chain or cyclic alkyl group having 1 to 25 carbon atoms, wherein 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 wherein one or more H atoms are each optionally replaced by F, Cl, P- or P-Sp-, and

[0522] Y 1 represents a halogen.

[0523] "Substituted silyl or aryl" preferably means that it is substituted by a halogen, -CN, R 0 , -OR 0 , -CO-R 0 , -CO-O-R 0 , -O-CO-R 0 or -O-CO-O-R 0 wherein R 0 represents H or an alkyl group having 1 to 20 carbon atoms.

[0524] 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 , OCF 3 , OCHF 2 , OC 2 F 5 , and in addition phenyl.

[0525] The LC medium according to the present invention may additionally comprise one or more other components or additives, preferably selected from the list consisting of, but not limited to: comonomers, polymerization initiators, inhibitors, stabilizers, surfactants, wetting agents, lubricants, dispersants, water repellents, binders, flow improvers, defoamers, degassing agents, diluents, reactive diluents, auxiliaries, colorants, dyes, pigments, and nanoparticles.

[0526] The LC medium according to the present invention may comprise one, two or three chiral dopants, preferably one chiral dopant.

[0527] The following lists preferred embodiments, either alone or in combination. The medium according to the present invention preferably comprises

[0528] - a compound of formula I, in a concentration in the range of 15% - 60%, preferably 20% - 50%, very preferably 25% - 45%;

[0529] - one or more compounds selected from formulae ST-1 and ST-12, in a concentration in the range of 0.01% - 0.85%, preferably 0.05% - 0.60%, very preferably 0.1% - 0.5%;

[0530] - a compound of formula H, preferably a compound of formula H-A, more preferably a compound of formula H-1, in a concentration in the range of 0.008% - 0.08%, preferably 0.012% - 0.06%, very preferably 0.015% - 0.04%;

[0531] - one or more compounds of formulae IIA, IIB, IIC, IID, IIE and III, in a total concentration in the range of 68% - 88%, more preferably 70% - 85%, very preferably 71% - 83%;

[0532] - one, two, three or more compounds of formula III, preferably compounds of formula III-1 and / or III-2, more preferably a compound of formula III-2, in a total concentration in the range of 0% - 15%, more preferably 1% - 12%, very preferably 2% - 10%, especially 3% - 8%;

[0533] - one or more compounds of formula IIA, in a total concentration in the range of 15% - 50%, more preferably 15% - 45%, very preferably 35% - 43% or 20% - 25%;

[0534] - one or more compounds of formula IIB-2, in a total concentration in the range of 1% - 30%, more preferably 1% - 25%, very preferably 1% - 10%;

[0535] - one or more compounds of formula IIB-10, with a total concentration in the range of 1% - 20%, more preferably 1% - 15%, and very preferably 1% - 10%;

[0536] - one or more compounds of formula IIB-2 and / or IIB-10, with a total concentration in the range of 1% - 30%, more preferably 1% - 20%, and very preferably 2% - 15%;

[0537] - one or more compounds selected from formula IIC, more preferably IIC-1 and IIC-2, preferably the compound of formula IIC-1, with a total concentration in the range of 1% - 25%, more preferably 1% - 20%, and very preferably 1% - 15%;

[0538] - one or more compounds of formula IIE, preferably the compound of formula IIE-1, with a total concentration in the range of 1% - 18%, more preferably 1% - 15%, and very preferably 1% - 12%;

[0539] - one or more compounds of formula III, more preferably selected from III-1, IIIA-1, III-2, and IIIA-2, with a total concentration in the range of 3% - 30%, more preferably 5% - 25%, and very preferably 7% - 22%;

[0540] - two or more diphenylacetylene compounds of formula I, T-1, T-2, and T-3, preferably selected from formula I-1, I-2, T-1, and T-3, with a total concentration in the range of 25% - 80%, more preferably 30% - 75%, and very preferably 35% - 65%;

[0541] - one or more diphenylacetylene compounds of formula T-1, T-2, and T-3, preferably selected from formula T-1 and T-3, with a total concentration in the range of 10% - 65%, more preferably 18% - 60%, and very preferably 18% - 56%;

[0542] - one or more compounds selected from formula IV-1 / 2 / 3 / 4, with a concentration in the range of 6% - 40%, preferably 7% - 38%, and very preferably 8% - 37%;

[0543] - the compound of formula IV-2, with a concentration in the range of 4% - 20%, preferably 5% - 15%, and very preferably 6% - 12%.

[0544] For the liquid crystal medium according to the invention, it is advantageous to preferably have a nematic phase of ≤ -20°C to ≥ 90°C, particularly preferably ≤ -30°C to ≥ 100°C, and very particularly preferably ≤ -40°C to ≥ 105°C.

[0545] In a preferred embodiment, the medium according to the invention has a clearing temperature (clearing point) of 80 °C or higher, more preferably 90 °C or higher, even more preferably 100 °C or higher, and especially 105 °C or higher.

[0546] Herein, the expression "having a nematic phase" at a given temperature means that no smectic phase and no crystallization are observed at low temperature and, on the other hand, means that no clearing (phase transition to the isotropic phase) occurs when heating the nematic phase at the given temperature. The low-temperature studies are carried out in a flow viscosimeter at the respective temperatures and are checked by storing in a test cell having a layer thickness corresponding to electro-optical use for at least 100 hours. If the storage stability in the respective test cell at a temperature of -20 °C is 1000 hours or more, the medium is said to be stable at this temperature. At the temperatures of -30 °C and -40 °C, the respective times are 500 hours and 250 hours. At high temperature, the clearing point is measured in a capillary by a conventional method.

[0547] The liquid-crystal mixture preferably has a nematic range of at least 60 K and a flow viscosity ν 2 ×s -1 of at most 30 mm 20 .

[0548] The mixture is nematic at a temperature of -20 °C or lower, preferably at -30 °C or lower, very preferably at -40 °C or lower.

[0549] The birefringence (Δn) of the medium according to the invention is in the range from 0.085 to 0.28, preferably from 0.13 to 0.26, and especially from 0.15 to 0.255.

[0550] In a preferred embodiment, the birefringence of the medium is from 0.15 to 0.20, preferably from 0.16 to 0.19.

[0551] In an alternative preferred embodiment, especially for phase modulation, the birefringence of the medium is from 0.19 to 0.28, preferably from 0.2 to 0.27, especially from 0.21 to 0.26.

[0552] In a preferred embodiment, the dielectric anisotropy Δε of the medium according to the invention is from -2.5 to -6.5, preferably from -2.8 to -5.2, especially from -3.5 to -4.9.

[0553] In a very preferred embodiment, the dielectric anisotropy Δε of the liquid-crystal mixture according to the invention is from -3.8 to -4.8.

[0554] The rotational viscosity γ at 20 °C 1 is preferably in the range from 90 to 300 mPa·s, more preferably from 100 to 290 mPa·s.

[0555] The elastic constant K of the medium according to the invention 1 is in the range from 16 - 22 pN, more preferably 18 pN or higher.

[0556] In a preferred embodiment, the ratio γ of the rotational viscosity to the splay elastic constant of the medium according to the invention 1 / K 1 is 15 mPa·s pN -1 or less.

[0557] The liquid crystal medium according to the invention has a relatively low threshold voltage (V 0 ). They are preferably in the range from 1.7 V to 3.0 V, particularly preferably ≤ 2.6 V and very particularly preferably ≤ 2.4 V.

[0558] For the purposes of the present invention, unless otherwise expressly stated, the term "threshold voltage" relates to the capacitive threshold (V 0 ), also known as the Freedericks threshold.

[0559] Furthermore, the liquid crystal medium according to the invention has a high voltage holding ratio value in the liquid crystal cell.

[0560] Generally, liquid crystal media with a low addressing voltage or threshold voltage show a lower voltage holding ratio than those LC media with a higher addressing voltage or threshold voltage, and vice versa.

[0561] For the purposes of the present invention, the term "dielectrically positive compound" denotes a compound having Δε > 1.5, the term "dielectrically neutral compound" denotes those having -1.5 ≤ Δε ≤ 1.5 and the term "dielectrically negative compound" denotes those having Δε < -1.5. Here, the dielectric anisotropy of the compound is determined by dissolving 10% of the compound in the liquid crystal host in at least one test cell and measuring the capacitance of the resulting mixture, each test cell having a layer thickness of 20 μm and homeotropic and planar surface alignment at 1 kHz. The measurement voltage is generally 0.5 V - 1.0 V, but always below the capacitance threshold of the respective liquid crystal mixture under investigation.

[0562] All temperature values stated in the present invention are in °C.

[0563] The mixtures according to the invention are suitable for all VA - TFT applications, such as VAN, MVA, (S) - PVA, ASV, PSA (polymer - stabilized alignment VA) and PS - VA (polymer - stabilized VA). Furthermore, they are also suitable for IPS (in - plane switching) and FFS (fringe - field switching) applications with negative Δε.

[0564] The mixture is also particularly suitable for VA-TFT applications of the LCoS type, more preferably for LCoS microdisplays. An LCoS microdisplay is a reflective display that typically includes a liquid crystal layer with a nematic structure between a silicon backplane and a cover glass. The silicon backplane is an array of pixels, each pixel having a mirror that also serves as an electrical conductor. Each pixel includes a fixed mirror covered by an active liquid crystal layer having a twisted nematic alignment that can be switched between a vertical alignment and a planar alignment by applying a voltage. LCoS microdisplays are small, typically having a diagonal of less than 1.0 inch, but still have a high resolution.

[0565] Due to the small pixel size, the cell thickness of LCoS displays is also very small, typically in the range of 1 - 2 microns. Therefore, the liquid crystal phases used in these displays need to have a high value of optical anisotropy Δn, whereas traditional reflective LC displays typically require liquid crystal phases with low Δn.

[0566] In a preferred embodiment, the LCoS panel according to the present invention includes an inorganic alignment layer, more preferably a vertical alignment layer for the vertical alignment of the liquid crystal medium. Such an inorganic alignment layer is particularly suitable for LCoS panels with high light intensity. Typical and preferred materials for these layers are silica (SiO x ) applied using a specific deposition technique.

[0567] LCoS devices provide a dense array of light modulation elements or pixels within a small aperture (e.g., a few centimeters wide). The pixels are typically about 10 microns or smaller, which means that the optical system can be compact. LCoS devices are typically reflective, which means that the circuitry driving the pixels of the LCoS can be buried beneath the reflective surface. This results in a higher aperture ratio, meaning that there is little dead space between the pixels. The LCoS panel uses a silicon backplane, which has the advantage that the pixels are optically flat. This is particularly important for phase modulation devices.

[0568] Therefore, in a preferred embodiment, referring to Figure 1 , there is provided a reflective spatial light modulator, particularly an LCoS panel 100, which includes a liquid crystal material 140 as defined above, sandwiched between a transparent glass layer 110 with a transparent electrode 120 and a pixelated mirror 150 and its mount (not shown) mounted on a silicon CMOS backplane 160. The mirror is divided into a two-dimensional array of individually addressable pixels. Each pixel can be individually driven 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.

[0569] The LCOS panel can be used for integration into an optical device. The described LCOS panel outputs spatially modulated light in reflection. The advantage of a reflective LCoS panel is that the signal lines, gate lines, and transistors are located beneath the mirror, which results in a high fill factor (typically greater than 90%) and high resolution. Another advantage of using a reflective LCOS spatial light modulator is that the thickness of the liquid crystal layer can be half of that required for a transmissive device. This significantly increases the switching speed of the liquid crystal (a key advantage for motion video image projection).

[0570] Examples of devices including an optical element 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 for a head-up display, an augmented reality head-up display "AR - HUD" including eye tracking or head tracking, a picture generation unit, and an integrated infrared holographic illuminator for head tracking or eye tracking.

[0571] The spatial light modulator can be used to display a diffraction pattern including a computer - generated hologram. If the hologram is a pure - phase hologram, a spatial light modulator that modulates the phase is required. If the hologram is a full - complex hologram, a spatial light modulator that modulates both the phase and the amplitude can be used, or a first spatial light modulator that modulates the phase and a second spatial light modulator that modulates the amplitude can be used.

[0572] Other preferred devices are infrared imagers, wavelength - selective switches, LCoS - SLMs, LIDAR systems, wavelength - division multiplexing (WDM) systems, reconfigurable optical add - drop multiplexers (ROADMs), and non - mechanical beam control, such as the steerable electro - escaped - light refraction (SEEOR) prism published in the article P. McManamon, 2006, "Agile Nonmechanical Beam Steering," Opt. Photon. News 17(3):24 - 29.

[0573] This technology combines an LCoS panel and a red - green - blue (RGB) light source. The red - green - blue (RGB) light source is configured to emit red, green, and blue light 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 using red, green, and blue micro - LED arrays, such as that proposed in EP3539157 A1.

[0574] RGB refers to the three primary colors of light, red, green, and blue, from which other colors and white can be formed. A traditional single LED may emit light of only one of these three primary colors (monochromatic). To create more colors, three LEDs can be used together for RGB mixing. An RGB LED is, in principle, three single-color LEDs placed close to each other, usually in the same package, in the colors red, green, and blue. When all the LEDs of an RGB-LED emit proportionally with the same luminous intensity and the correct optical elements are used, the light emitted by the RGB-LED appears white to the human eye.

[0575] The use of an RGB light source avoids exposing the liquid crystal to UV light, which is inevitable when using traditional light sources such as cold cathode fluorescent lamps.

[0576] According to another aspect of the present invention, there is thus provided an optical device comprising an RGB light source and the above-mentioned optical component, wherein when the optical device operates, the phase of the incident light signal from the RGB light source is modulated by the component.

[0577] According to another aspect of the present invention, there is provided a method for spatially modulating visible or infrared light, the method comprising:

[0578] i) providing an LCoS panel according to the present invention;

[0579] ii) receiving incident visible or infrared light at the surface of the LCoS panel;

[0580] iii) applying a predetermined voltage to each individual electrode of the LCoS panel to modulate the refractive index of the liquid crystal layer.

[0581] According to another aspect of the present invention, there is provided a method for manufacturing an LCoS panel, comprising at least the following steps:

[0582] a) providing a first substrate having a first electrode with a two-dimensional array of pixels that can be individually electrically driven;

[0583] b) depositing a preferred liquid crystal medium as disclosed herein on the first substrate; and

[0584] c) mounting a second substrate having a second electrode onto the liquid crystal material.

[0585] It goes without saying for those skilled in the art that the liquid crystal mixture used in the present invention may also contain, for example, compounds in which H, N, O, Cl, F are replaced by corresponding isotopes such as deuterium.

[0586] The compounds according to the invention can be synthesized by or in a manner analogous to 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) under reaction conditions known and suitable for the said reactions. Variants which 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 in a similar manner. Other methods for preparing the compounds according to the invention can be obtained from the examples.

[0587] In the medium according to the invention, it is also possible, optionally and advantageously, to use other mesogenic compounds which are not explicitly mentioned above. These compounds are known to the person skilled in the art.

[0588] For the present invention and in the following examples, the structures of the liquid-crystalline compounds are represented by means of abbreviations which are converted into chemical formulae in accordance with Tables A to C below. All groups 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 straight-chain alkyl groups or alkylene groups, each having n, m and l C atoms in each case. Preferably, n, m and l are each independently 1, 2, 3, 4, 5, 6 or 7. Table A shows the codes for the ring elements of the compound nucleus, Table B lists the bridging units, and Table C lists the symbolic meanings of the left- and right-hand end groups of the molecule. The abbreviations consist of the code for the ring element with an optional linking group, followed by a first hyphen and the left-hand end group code, and a second hyphen and the right-hand end group code. Table D shows exemplary structures of the compounds and their respective abbreviations.

[0589] Table A: Ring Elements

[0590]

[0591]

[0592]

[0593] Table B: Bridging Units

[0594]

[0595]

[0596] Table C: Terminal Groups

[0597]

[0598]

[0599] where n and m are each integers, and the three dots "..." are placeholders for other abbreviations from this table.

[0600] In addition to the compounds of Formulae IV-2, I and ST-1, the mixtures according to the invention optionally comprise one or more compounds from Table D.

[0601] The following abbreviations are used, where:

[0602] (n, m, k and l are each independently of one another integers, preferably 1 - 9, more preferably 1 - 7, k and l may also be 0 and are preferably 0 - 4, more preferably 0 or 2, and most preferably 2, n is preferably 1, 2, 3, 4 or 5, in the combination "-nO-", it is preferably 1, 2, 3 or 4, more preferably 2 or 4, m is preferably 1, 2, 3, 4 or 5, in the combination "-Om", it is preferably 1, 2, 3 or 4, more preferably 2 or 4. The combination "-lVm" is preferably "2V1").

[0603] Table D

[0604]

[0605]

[0606]

[0607]

[0608]

[0609]

[0610]

[0611]

[0612]

[0613]

[0614]

[0615]

[0616]

[0617]

[0618]

[0619]

[0620]

[0621]

[0622] Table E shows the chiral dopants preferably used in the mixtures according to the invention.

[0623] Table E

[0624]

[0625]

[0626]

[0627] In a preferred embodiment of the invention, the medium according to the invention comprises one or more compounds selected from Table E. Detailed Description

[0628] Examples

[0629] The invention is illustrated in detail by the following non-limiting working examples.

[0630] The following abbreviations and symbols are used:

[0631] V 0 represents the threshold voltage at 20 °C, capacitive [V],

[0632] n e represents the extraordinary refractive index at 20 °C and 589 nm,

[0633] n o represents the ordinary refractive index at 20 °C and 589 nm,

[0634] Δn represents the optical anisotropy at 20 °C and 589 nm,

[0635] ε ⊥ represents the dielectric constant perpendicular to the director at 20 °C and 1 kHz,

[0636] ε ||denotes the dielectric constant parallel to the director at 20 °C and 1 kHz,

[0637] Δε denotes the dielectric anisotropy at 20 °C and 1 kHz,

[0638] cl.p., T(N,I) denotes the clearing point [°C],

[0639] γ 1 denotes the rotational viscosity [mPa·s] at 20 °C,

[0640] K 1 denotes the elastic constant at 20 °C, "splay" deformation [pN],

[0641] K 2 denotes the elastic constant at 20 °C, "twist" deformation [pN],

[0642] K 3 denotes the elastic constant at 20 °C, "bend" deformation [pN].

[0643] Unless otherwise explicitly stated, all concentrations in this application are given as weight percentages and relate to the corresponding entire mixture, which includes all solid or liquid crystal components (without solvent).

[0644] Unless otherwise specified, all temperature values indicated in this application, such as the melting point T(C,N), the transition from the smectic phase (S) to the nematic phase (N) T(S,N), and the clearing point T(N,I), are expressed in degrees Celsius (°C). M.p. denotes the melting point, cl.p. = clearing point. In addition, C = liquid crystal phase, N = nematic phase, S = smectic phase, and I = isotropic phase. The data between these symbols represent the transition temperatures.

[0645] All physical properties are and have been determined according to "Merck Liquid Crystals, Physical Properties of Liquid Crystals" Status November 1997, Merck KGaA, Germany, and apply to a temperature of 20 °C, and Δn is measured at 589 nm and Δε is measured at 1 kHz, unless otherwise explicitly stated in each case.

[0646] The term "threshold voltage" used in this invention relates to the capacitive threshold (V 0 ), which is also referred to as the Freedericks threshold, unless otherwise specified. In the examples, the optical threshold is also given as usual for a relative contrast of 10% (V 10 ).

[0647] Unless otherwise specified, the method of preparing the test cells and measuring their electro-optical and other properties is carried out by the method described below or a similar method.

[0648] The display for measuring the capacitive threshold voltage consists of two planar parallel glass outer plates with a distance of 25 μm between them. Each outer plate has an electrode layer on the inner side and an unrubbed polyimide alignment layer on the top, which results in a homeotropic alignment of liquid crystal molecules.

[0649] Unless otherwise specified, VHR is measured at 20 °C (VHR 20 ) and after being placed in an oven at 100 °C for 5 minutes (VHR 100 ) using a commercially available instrument Model LCM-1 (O0004) from TOYO Corporation, Japan. Unless otherwise specified more precisely, the frequency range of the applied voltage is from 1 Hz to 60 Hz.

[0650] The stability against ultraviolet irradiation is studied using a xenon lamp NXE1500B in a commercially available instrument “Suntest CPS+” from Heraeus, Germany. Unless otherwise explicitly specified, the sealed test cells are irradiated for 2.0 hours without additional heating. The radiation power in the wavelength range from 300 nm to 800 nm is 765 W / m 2 V. A UV “cut-off” filter with a cut-off wavelength of 310 nm is used to simulate the so-called window glass mode. In each series of experiments, at least four test cells are studied for each condition, and the corresponding results are expressed as the average of the corresponding individual measurements.

[0651] To study the low-temperature stability (also referred to as “LTS”), i.e., the stability of the liquid crystal mixture in the bulk against spontaneous crystallization of individual components or the appearance of a smectic phase at low temperatures (as the case may be), several sealed vials (each containing approximately 1 g of material) are stored at one or more given temperatures, typically -10 °C, -20 °C, -30 °C, and / or -40 °C, and visually inspected regularly for the observation of phase changes. Once a change occurs in the first sample at a given temperature, the time is recorded. The time until no change is observed at the last inspection is recorded as the corresponding LTS.

[0652] The ion density required for calculating the resistivity was measured using a commercially available LC Material Characteristics Measurement System Model 6254 from Toyo Corporation, Japan, with a cell gap of 3.2 μm and a VHR test cell with AL16301 Polyimide (JSR Corp., Japan). The measurement was carried out after storing in an oven at 60 °C or 100 °C for 5 minutes.

[0653] The clearing point was measured using a Mettler Thermosystem FP900. The optical anisotropy (Δn) was measured using an Abbe Refractometer H005 (Natrium-spectral lamp Na10, 589 nm, 20 °C). The dielectric anisotropy (Δε) was measured using an LCR-Meter E4980A / Agilent (G005) at 20 °C (ε-parallel cell with JALS2096-R1). The threshold voltage (V 0 ) was measured using an LCR-Meter E4980A / Agilent (G005) at 20 °C (ε-parallel cell with JALS2096-R1). The rotational viscosity (γ 1 ) was measured using a TOYO LCM-2 (0002) at 20 °C (γ1-negative cell with JALS2096-R1). The elastic constant (K 1 , splay) was measured using an LCR-Meter E4980A / Agilent (G005) at 20 °C (ε-parallel cell with JALS2096-R1). K 3 : The elastic constant (K 3 , bend was measured using an LCR-Meter E4980A / Agilent (G005) at 20 °C (ε-parallel cell with JALS2096-R1).

[0654] The following mixture examples with negative dielectric anisotropy are particularly suitable for vertically aligned liquid crystal displays.

[0655] Mixture Examples

[0656] The stabilizing compounds used are as follows, with their abbreviations as follows:

[0657]

[0658] The following nematic LC mixtures have the compositions and physical properties given in the following table: Comparative Mixture CM1

[0659]

[0660]

[0661] Example Mixture M2

[0662]

[0663] Example Mixture M3

[0664]

[0665] Example Mixture M4

[0666]

[0667]

[0668] Example Mixture M5

[0669]

[0670] This mixture is particularly suitable for phase modulation with short switching times.

[0671] Example Mixture M6

[0672]

[0673] This mixture is particularly suitable for phase modulation with short switching times.

[0674] The mixture of the above embodiment was filled into a test cell (d = 2.5 μm) or an LCoS panel having an inorganic alignment (SiO x ) layer at 20 °C. The alignment was tested using crossed polarizers. The cell was further observed with a camera at a magnification of (x3). These devices were tested under forced temperature and light (30 h under 300 mW / cm 2 , 460 nm LED). The appearance of bubbles and dark stains (color difference) was avoided for a long time. The alignment was found to be vertical and stable. The following table summarizes further results regarding reliability.

[0675] Table 1. Results of mixtures identified by number.

[0676]

[0677] (+) : Provides the feature, (-) does not provide, (o) no / uncertain result.

Claims

1. A liquid crystal on silicon (LCoS) panel comprising: a semiconductor substrate having a plurality of reflective electrodes, a transparent substrate including a transparent electrode assembled with the semiconductor substrate, and a liquid crystal layer arranged between the semiconductor substrate and the transparent substrate, The liquid crystal layer comprises a liquid crystal medium, and the liquid crystal medium comprises a) one or more compounds of formula I in R 11 and R 12 represents an alkyl radical having 1 to 7 C atoms, an alkoxy radical having 1 to 7 C atoms or an alkoxyalkyl radical, an alkenyl radical or an alkenyloxy radical having 2 to 7 C atoms, wherein, in addition, one or more CH2 radicals in these radicals may each independently of one another be Instead, for Z 1 represents a single bond, -CH2CH2- or -(CO)O-, n independently represents 0 or 1, L 11 , L 12 , L 13 , L 14 independently represents H or methyl, b) one or more compounds of formula III in R 31 and R 32 each independently of one another represents H, alkyl or alkoxy having 1 to 7 C atoms, wherein one or more CH2 groups in these groups can each independently of one another be -C≡C-, -CF2O-, -OCF2-, -CH=CH-, -O-, -CO-O- or -O-CO- are substituted in such a way that the O atoms are not directly connected to each other, and wherein one or more H atoms may be replaced by halogen, A 3 represents, independently of one another, on each occurrence 1,4-phenylene, in which one or two CH groups may be replaced by N, or 1,4-cyclohexylene or 1,4-cyclohexenylene, in which one or two non-adjacent CH2 groups may be replaced by -O- or -S-, The groups may be substituted singly or polysubstituted by halogen atoms. n represents 0, 1 or 2, Z 3 represents, independently of one another, at each occurrence -CF2O-, -OCF2-, -CH2O-, -OCH2-, -CH2-, -CH2CH2-, -CH=CH-, -C≡C- or a single bond, L 31 and L 32 Each independently represents F, Cl, CF3 or CHF2, and W means O or S, and c) one or more compounds of formula IV in R 41 represents an unsubstituted alkyl group having 1 to 7 C atoms or an unsubstituted alkenyl group having 2 to 7 C atoms, and R 42 represents an unsubstituted alkyl group having 1 to 7 C atoms, an unsubstituted alkoxy group having 1 to 6 C atoms or an unsubstituted alkenyl group having 2 to 7 C atoms.

2. The LCoS panel according to claim 1, comprising one or more inorganic alignment layers.

3. The LCoS panel according to claim 1 or 2, wherein the clearing point of the liquid crystal medium is 90°C or higher.

4. LCoS panel according to one or more of claims 1 to 3, wherein the liquid crystal medium is aligned homeotropically with respect to the substrates.

5. The LCoS panel according to one or more of claims 1 to 4, wherein the liquid crystal medium comprises One or more compounds of formula IV selected from formula IV-2 in Alkyl represents an alkyl group having 1 to 7 C atoms, and Alkoxy represents an alkoxy group having 1 to 5 C atoms.

6. A liquid crystal medium comprising a) one or more compounds of formula I in R 11 and R 12 represents an alkyl group having 1 to 7 C atoms, an alkoxy group having 1 to 7 C atoms, or an alkoxyalkyl group, an alkenyl group or an alkenyloxy group having 2 to 7 carbon atoms, wherein Furthermore, one or more CH2 groups in these groups may each independently of one another be Instead, for Z 1 represents a single bond, -CH2CH2- or -(CO)O-, n independently represents 0 or 1, L 11 , L 12 , L 13 , L 14 independently represents H or methyl, b) one or more compounds of formula III in R 31 and R 32 each independently of one another represents H, alkyl or alkoxy having 1 to 7 C atoms, wherein one or more CH2 groups in these groups can each independently of one another be -C≡C-, -CF2O-, -OCF2-, -CH=CH-, -O-, -CO-O- or -O-CO- are substituted in such a way that the O atoms are not directly connected to each other, and wherein one or more H atoms may be replaced by halogen, A 3 represents, independently of one another, on each occurrence 1,4-phenylene, in which one or two CH groups may be replaced by N, or 1,4-cyclohexylene or 1,4-cyclohexenylene, in which one or two non-adjacent CH2 groups may be replaced by -O- or -S-, The radicals may be mono- or poly-substituted by halogen atoms, preferably 1,4-cyclohexylene or 1,4-cyclohexenylene, n represents 0, 1 or 2, Z 3 represents, independently of one another, at each occurrence -CF2O-, -OCF2-, -CH2O-, -OCH2-, -CH2-, -CH2CH2-, -CH=CH-, -C≡C- or a single bond, L 31 and L 32 Each independently represents F, Cl, CF3 or CHF2, and W means O or S, and c) one or more compounds of formula IV in R 41 represents an unsubstituted alkyl group having 1 to 7 C atoms or an unsubstituted alkenyl group having 2 to 7 C atoms, and R 42 represents an unsubstituted alkyl group having 1 to 7 C atoms, an unsubstituted alkoxy group having 1 to 6 C atoms or an unsubstituted alkenyl group having 2 to 7 C atoms.

7. A liquid crystal medium according to claim 6, wherein the medium comprises one or more compounds selected from group e): e) Formulas IIA, IIB, IIC, IID and IIE, in R 1A , R 1B , R 1C and R 1D Each independently of one another represents H, alkyl having 1 to 7 C atoms or alkenyl having 2 to 7 C atoms, each of which is unsubstituted or at least monosubstituted by halogen, wherein one or more CH2 groups in these groups may be replaced by -O-, -S-, -C≡C-, -CF2O-, -OCF2-, -OC-O- or -O-CO- are substituted in such a way that the O atoms are not directly connected to each other; R 2A , R 2B , R 2C and R 2D Each independently of one another represents H, alkyl having 1 to 7 C atoms or alkenyl having 2 to 7 C atoms, each of which is unsubstituted or at least monosubstituted by halogen, wherein one or more CH2 groups in these groups may be replaced by -O-, -S-, -C≡C-, -CF2O-, -OCF2-, -OC-O- or -O-CO- are substituted in such a way that the O atoms are not directly connected to each other; L 1 and L 2 Each independently represents F, Cl, CF3 or CHF2; Y represents H, F, Cl, CF3, CHF2 or CH3; Z 2 , Z 2B and Z 2D Each independently represents a single bond, -CH2CH2-, -CF2O-, -OCF2-, -CH2O-, -OCH2-, -COO-, -OCO-; R 1E independently represents H, alkyl having 1 to 7 C atoms or alkenyl having 2 to 7 C atoms, each of which is unsubstituted or at least monosubstituted by halogen, wherein one or more CH2 groups in these groups may be replaced by -O-, -S-, -C≡C-, -CF2O-, -OCF2-, -OC-O- or -O-CO- are substituted in such a way that the O atoms are not directly connected to each other; R 2E independently represents 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 by halogen, wherein one or more CH2 radicals in these radicals may be Replacement; p represents 0, 1 or 2, q represents 0 or 1, and v means 1, 2, 3, 4, 5, or 6.

8. Liquid-crystalline medium according to one or more of claims 6 to 7, wherein the medium comprises one or more compounds selected from the group consisting of formulae T-1 to T-3: Where R 11 , R 12 represents an alkyl group having 1 to 7 C atoms, an alkoxy group having 1 to 7 C atoms, or an alkoxyalkyl group, an alkenyl group or an alkenyloxy group having 2 to 7 carbon atoms, wherein Furthermore, one or more CH2 groups in these groups may each independently of one another be Instead, Z 1 For single bonds, -CH2CH2-, -CH=CH-, -CF2O-, -OCF2-, -CH2O-, -OCH2-, -COO-, -OCO-, -C2F4-, -CF=CF- or -CH=CHCH2O-, L 11 , L 12 is H, F or CH3, where L 11 and L 12 Not all are F, as well as L 13 It is H or F.

9. Liquid-crystalline medium according to one or more of claims 6 to 8 for use in LCoS panels. 10 . The LCoS panel according to claim 1 , wherein the liquid crystal medium is the liquid crystal medium according to claim 6 .

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

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

13. Use of the liquid-crystalline media according to one or more of claims 6 to 9 for energy-saving LC displays.

14. The method for manufacturing an LCoS panel according to claim 1, comprising at least the following steps: a) providing a first substrate having a first electrode, wherein the first electrode has a two-dimensional array of pixels that can be electrically driven individually; b) depositing the liquid crystal medium as claimed in claim 6 on a first substrate; and c) Mounting a second substrate having a second electrode onto the liquid crystal material.

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