Liquid crystal medium comprising polymerizable compounds

Abstract

The present invention relates to liquid crystal (LC) media comprising polymerizable compounds having absorption in the long UV wavelength range, for optical, electro-optical and electronic purposes, in particular for use in LC displays, in particular in PSA (polymer stabilized alignment) or SA (self-aligned) mode LC displays, PSA or SA mode LC displays comprising such LC media, and methods for producing such LC displays.

Description

[0001] The present invention relates to liquid crystal (LC) media comprising polymerizable compounds having absorption in the long UV wavelength range, for optical, electro-optical and electronic purposes, in particular for use in LC displays, in particular in PSA (polymer stabilized alignment) or SA (self-aligned) mode LC displays, PSA or SA mode LC displays comprising such LC media, and methods for producing such LC displays.

[0002] The popularity of 8K and gaming monitors has led to an increase in demand for LC display (LCD) panels with higher refresh rates and, therefore, LC media with faster response times. Many of these LCD panels use polymer-stabilized (PS) or polymer-stabilized alignment (PSA) modes, such as PS-VA (vertically aligned), PS-IPS (in-plane switching) or PS-FFS (fringe field switching) modes or their derivatives, or self-aligned (SA) modes such as SA-VA, which are polymer-stabilized.

[0003] In PS or PSA mode, small amounts, typically 0.1-1%, of one or more polymerizable mesogenic compounds, also called RMs (reactive mesogens), are added to the LC medium. After the LC medium has been filled into the display, the RMs are then polymerized in situ by UV photopolymerization while a voltage is applied to the electrodes of the display. Thereby, small tilt angles are generated in the LC molecules of the LC medium, which are stabilized by the polymerized RMs. The UV polymerization process (also called "PSA process") is usually carried out in two steps: a first UV exposure step ("UV1 step"), with application of a voltage to generate the tilt angle, and a second UV exposure step ("UV2 step"), without application of a voltage, to complete the RM polymerization.

[0004] In SA-VA mode, the alignment layer is omitted from the display. Instead, a small amount, typically 0.1-2.5%, of a self-aligning (SA) additive is added to the LC medium, which triggers the desired alignment, such as vertical or planar alignment, in situ by a self-assembly mechanism. The SA additive generally contains an organic mesogenic core group to which is attached one or more polar anchoring groups, such as hydroxyl, carboxyl, amino or thiol groups, which are capable of interacting with the substrate surface, resulting in the alignment of the additive on the substrate surface and inducing the desired alignment in the LC molecules. The SA additive may also contain one or more polymerizable groups, which can be polymerized under conditions similar to the RMs used in the PSA method. In addition to the SA additive, the LC medium contains one or more RMs.

[0005] One way to reduce the response time of the LC medium to the PSA mode is, for example, by using compounds with alkenyl groups as components of the LC host mixture. However, this can lead to reduced reliability of the mixture when exposed to the UV light required to polymerize the RM additive, which is believed to be caused by the reaction of the alkenyl compound with the polyimide of the alignment layer, which is particularly problematic when using shorter UV wavelengths of less than 320 nm. Therefore, there is a trend to use longer UV wavelengths for the PSA process.

[0006] It is also suggested to use UV-LED lamps in the PSA process, because they show less energy consumption, longer lifetime and more efficient light energy transfer to the LC medium due to narrower emission peaks, which allows to reduce UV intensity and / or UV irradiation time. This can shorten cycle time and save energy and production costs. Currently available UV lamps have higher wavelength emission, for example at 365nm.

[0007] Therefore, there is a need for polymerisable LC media containing RMs that can be efficiently polymerised at longer UV wavelengths.

[0008] Furthermore, there is a great need for PSA or SA displays and LC media and polymerizable compounds for such PSA or SA displays which are capable of having a high specific resistance, at the same time a large operating temperature range, a short response time, even at low temperatures, and a low threshold voltage, a low tilt angle, a high tilt stability, a wide range of gray scales, a high contrast ratio and a wide viewing angle, a high reliability and high VHR values ​​after UV exposure, and in the case of polymerizable compounds, a low melting point and a high solubility in the LC host mixture. In displays for mobile applications, it is particularly desirable to have available LC media which exhibit a low threshold voltage and a high birefringence.

[0009] It is an object of the present invention to provide novel suitable materials, in particular RMs and LC media comprising RMs, for use in PSA or SA displays which do not have the abovementioned disadvantages or have them to a reduced extent.

[0010] In particular, the present invention aims to provide an LC medium comprising RMs for use in PSA or SA displays, which medium can have very high specific resistance values, high VHR values, high reliability, low threshold voltage, short response time, high birefringence, show good UV absorption (especially at longer UV wavelengths, preferably 340-380 nm), can quickly and completely polymerize the RMs, can produce low tilt angles (preferably as quickly as possible), can have high tilt angle stability (even after longer times and / or after UV exposure), reduce or prevent the occurrence of "image sticking" and "ODF mura" in the display, and, in the case of the RMs being polymerized as quickly and completely as possible, show high solubility in the LC medium (which is typically used as a host mixture for PSA or SA displays).

[0011] It was a further object of the present invention to provide LC media for PSA displays in which the RMs exhibit both a fast polymerization speed and good reliability parameters, such as a high VHR or tilt stability.

[0012] It is a further object of the present invention to provide novel LC media containing RMs, in particular for optical, electro-optical and electronic applications, and suitable processes and intermediates for the preparation of said LC media.

[0013] It is a further object of the present invention to provide LC media containing RMs which exhibit one or more of the following advantageous effects:

[0014] - They produce the desired angle of inclination after exposure to UV light,

[0015] - they lead to high tilt stability,

[0016] - they show good UV absorption, especially at higher UV wavelengths, especially at 340-400nm, and the RMs are able to polymerize quickly and completely at these wavelengths,

[0017] - they are suitable for PSA displays prepared by polymerization processes using UV-LED lamps,

[0018] - they enable good control over the first UV step time range, where the tilt angle is created during the UV process,

[0019] - they are able to maintain the time frame of the second UV step, where any remaining RMs are polymerized and the tilt angle is stabilized, keeping production costs as low as possible,

[0020] - after the first and second UV exposure steps, the residual RMs have less or no negative impact on the performance parameters of the LC mixture, such as VHR, tilt stability, etc.,

[0021] - They show good solubility and stability in LC mixtures over a wide temperature range, preferably from -40 to 140 °C.

[0022] It has been found that one or more of these objects can be achieved by providing LC media as described and claimed herein.

[0023] The present invention therefore relates to LC media having a negative dielectric anisotropy and comprising one or more polymerisable compounds which show absorption in the range from 340 to 400 nm, preferably in the range from 350 to 370 nm, and further comprising one or more compounds of formula II

[0024]

[0025] where the radicals are independent of one another and have the following meanings on each occurrence, identically or differently:

[0026] R 1 and R 2 is a straight-chain, branched or cyclic alkyl radical having 1 to 25 C atoms, wherein one or more non-adjacent CH2 groups are optionally replaced by -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O-, CR- 0 =CR 00 -、-C≡C-、 substituted, and wherein one or more H atoms are each optionally replaced by F or Cl, preferably alkyl or alkoxy having 1 to 6 C atoms,

[0027] R 0 and R 00 is H or an alkyl group having 1 to 12 C atoms, preferably H,

[0028] A 1 and A 2 is a group selected from the following formula

[0029]

[0030]

[0031] Preferred are the formulae A1, A2, A3, A4, A5, A6, A9 and A10, very preferred are the formulae A1, A2, A3, A4, A5, A9 and A10,

[0032] Z 1 and Z 2is -CH2CH2-, -CH=CH-, -CF2O-, -OCF2-, -CH2O-, -OCH2-, -CO-O-, -O-CO-, -C2F4-, -CF=CF-, -CH=CH-CH2O- or a single bond, preferably a single bond,

[0033] L 1 ,L 2 ,L 3 and L 4 is F, Cl, OCF3, CF3, CH3, CH2F or CHF2, preferably F or Cl, very preferably F,

[0034] Y is H, F, Cl, CF3, CHF2 or CH3, preferably H or CH3, very preferably H,

[0035] L C is CH3 or OCH3, preferably CH3,

[0036] a1 is 1 or 2,

[0037] a2 is 0 or 1.

[0038] The invention furthermore relates to the use of an LC medium as described above and below in a PSA or SA mode LC display.

[0039] The invention further relates to a process for preparing an LC medium as described above and below, comprising the step of mixing one or more polymerisable compounds having an absorption in the range of 340 to 400 with one or more compounds of formula II and optionally with other LC compounds and / or additives.

[0040] The invention further relates to an LC display comprising an LC medium according to the invention as described above and below, which is a PSA or SA display, preferably a PS-VA, PS-IPS, PS-FFS or SA-VA display.

[0041] The invention further relates to an LC display comprising an LC medium as described above and below, wherein the polymerisable compound is present in polymerised form, preferably a PSA or SA display, very preferably a PS-VA, PS-IPS, PS-FFS or SA-VA display.

[0042] The invention further relates to a PSA type LC display comprising two substrates, at least one of which is transparent to light, one electrode arranged on each substrate or two electrodes arranged on only one substrate, and a layer of an LC medium as described above and below located between the substrates, wherein the polymerizable compound is polymerized between the substrates of the display by UV photopolymerization.

[0043] The present invention also relates to a method for producing an LC display as described above and below, comprising the steps of filling or otherwise providing an LC medium as described above and below between substrates of the display, and polymerizing the polymerizable compounds, preferably by irradiation with UV light, preferably having a wavelength >340 nm, preferably in the range of 340 to 400 nm, more preferably in the range of 340 to 380 nm, very preferably in the range of 350 to <370 nm, most preferably in the range of 355 to 368 nm, preferably while applying a voltage to the electrodes of the display.

[0044] The invention further relates to a process for producing an LC display as described above and below, wherein the irradiation of the polymerisable compounds is carried out using UV-LED lamps.

[0045] When used in PSA displays, the LC media according to the invention exhibit the following advantageous properties:

[0046] - suitable tilt generation within a certain process window,

[0047] - Rapid polymerization, which minimizes the amount of RM residue after UV treatment.

[0048] -High voltage holding rate after UV treatment,

[0049] - good tilt stability,

[0050] -Sufficient thermal stability,

[0051] - Have sufficient solubility in organic solvents typically used in display manufacturing.

[0052] Additionally, the LC media of the present invention contribute to solving one or more of the following problems:

[0053] - Produces the desired angle of tilt after UV exposure,

[0054] - Provides high tilt stability,

[0055] - exhibits good UV absorption, especially at longer UV wavelengths, preferably in the range of 340 to 400 nm, more preferably in the range of 340 to 380 nm, very preferably in the range of 350 to <370 nm, most preferably in the range of 355 to 368 nm, and is able to polymerize RM rapidly and completely at these wavelengths,

[0056] - Suitable for PSA displays prepared by a polymerization process using UV-LED lamps,

[0057] - During UV processing, controls the time range of the first UV step that produces the tilt angle,

[0058] - shorten the time frame of the second UV step as much as possible to minimize production costs,

[0059] - reducing or avoiding any negative impact of residual RMs on LC mixture performance parameters, such as VHR, tilt stability, etc., after the first and second UV exposure steps,

[0060] - Provides good solubility and stability in LC host mixtures over a wide temperature range, preferably -40°C to about 140°C.

[0061] As described below, alkenyl groups in compounds of formula II or other components of the LC medium are not to be regarded as falling within the meaning of the term "polymerizable group" as used herein. The polymerisation conditions for the polymerizable compounds of the LC medium are preferably chosen such that the alkenyl substituents do not participate in the polymerisation reaction. Preferably, the LC medium disclosed and claimed in the present application does not contain additives which initiate or enhance the participation of alkenyl groups in polymerisation reactions.

[0062] Unless otherwise stated, the polymerizable compound and the compound of formula II are preferably selected from achiral compounds.

[0063] As used herein, the expression "UV light having a wavelength of..." followed by a given range of wavelengths (in nm), or a given lower or upper wavelength limit (in nm), indicates that the UV emission spectrum of the corresponding radiation source has an emission peak, which is preferably the highest peak in the corresponding spectrum within the given wavelength range, or above the given lower wavelength limit, or below the given upper wavelength limit, and / or the UV absorption spectrum of the corresponding chemical compound has a long wavelength tail or a short wavelength tail extending into the given wavelength range, or above the given lower wavelength limit, or below the given upper wavelength limit.

[0064] As used herein, the term "full width at half maximum" or "FWHM" refers to the width of a spectrum curve measured between those points on the y-axis that are half the maximum amplitude.

[0065] As used herein, the term "substantially transmits" means that the filter transmits a substantial portion of incident light of a desired wavelength, preferably at least 50% intensity. As used herein, the term "substantially blocks" means that the filter does not transmit a substantial portion of incident light of an undesired wavelength, preferably at least 50% intensity. As used herein, the term "desired (undesired) wavelength" means, for example, for a bandpass filter, a wavelength within (outside) a given range λ, and for a cutoff filter, a wavelength above (below) a given λ value.

[0066] As used herein, the terms "active layer" and "switchable layer" refer to a layer in an electro-optical display, such as an LC display, which comprises one or more molecules, such as LC molecules, having structural and optical anisotropy, which molecules change their orientation when subjected to an external stimulus, such as an electric or magnetic field, resulting in a change in the transmittance of the layer for polarized or unpolarized light.

[0067] As used herein, the terms "tilt" and "tilt angle" are to be understood as meaning the tilted alignment of the LC molecules of an LC medium relative to the cell surface in an LC display, preferably a PSA display herein, and are to be understood as including "pretilt" and "pretilt angle". The tilt angle herein refers to the average angle (<90°) between the longitudinal molecular axis of the LC molecules (LC director) and the plane-parallel outer plate surfaces forming the LC cell. Low absolute values ​​of the tilt angle (i.e. large deviations from an angle of 90°) correspond herein to large tilts. A suitable method for measuring the tilt angle is given in the Examples. Unless otherwise stated, the tilt angle values ​​disclosed above and below relate to this measurement method.

[0068] As used herein, the terms "reactive mesogen" and "RM" are understood to mean a compound containing a mesogenic or liquid crystal backbone and attached thereto one or more functional groups suitable for polymerization, and the functional groups are also referred to as "polymerizable groups" or "P".

[0069] Unless otherwise indicated, the term "polymerizable compound" as used herein shall be understood to mean a polymerizable monomeric compound.

[0070] The SA-VA displays of the present invention will be of polymer-stabilized mode since they comprise or are manufactured by using an LC medium comprising RMs of formulae I and II. Therefore as used herein, even if not explicitly mentioned, the term "SA-VA display" when referring to the displays of the present invention is to be understood as meaning a polymer-stabilized SA-VA display.

[0071] As used herein, the term "low molecular weight compound" is understood to mean a monomer and / or a compound that is not prepared by polymerization, as opposed to a "polymeric compound" or "polymer."

[0072] As used herein, the term "non-polymerizable compound" will be understood to mean a compound that does not contain functional groups suitable for polymerization under the conditions normally applied to RM polymerization.

[0073] As used herein, the term "mesogenic group" is known to those skilled in the art and is described in the literature and refers to a group that substantially contributes to the generation of a liquid crystal (LC) phase in a low molecular weight or polymeric substance due to its anisotropy of attractive and repulsive interactions. A compound containing a mesogenic group (mesogenic compound) does not necessarily have an LC phase per se. A mesogenic compound can exhibit LC phase behavior only after mixing with other compounds and / or after polymerization. Typical mesogenic groups are, for example, rigid rod-shaped or disc-shaped units. Terms and definitions used in connection with mesogenic or LC compounds are given in Pure Appl. Chem. 2001, 73 (5), 888 and C. Tschierske, G. Pelzl, S. Diele, Angew. Chem. 2004, 116, 6340-6368.

[0074] As used herein, the term "spacer" (hereinafter also referred to as "Sp") is known to those skilled in the art in the art and is described in the literature, see for example Pure Appl. Chem. 2001, 73 (5), 888 and C. Tschierske, G. Pelzl, S. Diele, Angew. Chem. 2004, 116, 6340-6368. As used herein, the term "spacer" or "spacer" refers to a flexible group, for example an alkylene group, which is connected to a mesogenic group or a polymerizable group in a polymerizable mesogenic compound.

[0075] In context, represents a trans-1,4-cyclohexylene ring, and It represents a 1,4-phenylene ring.

[0076] In the group In the case of phenylene, the single bond between two ring atoms can be connected to any free position of the benzene ring.

[0077] If in the formulae shown above and below, the group R 1-12 , R Q , R or L represents alkyl and / or alkoxy, which may be straight-chain or branched. It is preferably straight-chain, has 2, 3, 4, 5, 6 or 7 C atoms and correspondingly preferably represents ethyl, propyl, butyl, pentyl, hexyl, heptyl, ethoxy, propoxy, butoxy, pentyloxy, hexyloxy or heptoxy, as well as methyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, methoxy, octyloxy, nonyloxy, decyloxy, undecyloxy, dodecyloxy, tridecyloxy or tetradecyloxy.

[0078] If the group R 1-13 ,R 51 ,R52 ,R Q ,R,R 2A ,R 2B ,R IIIA ,R 1N ,R 2N ,R B1 ,R B2 ,R CR1 ,R CR2 , R or L represents alkyl and / or alkoxy, which may be straight-chain or branched. It is preferably straight-chain, has 2, 3, 4, 5, 6 or 7 C atoms and correspondingly preferably represents ethyl, propyl, butyl, pentyl, hexyl, heptyl, ethoxy, propoxy, butoxy, pentyloxy, hexyloxy or heptyloxy, as well as methyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, methoxy, octyloxy, nonyloxy, decyloxy, undecyloxy, dodecyloxy, tridecyloxy or tetradecyloxy.

[0079] If the group R 1-13 ,R 51 ,R 52 ,R Q ,R,R 2A ,R 2B ,R IIIA ,R 1N ,R 2N ,R B1 ,R B2 ,R CR1 ,R CR2 , R or L represents alkyl in which one or more CH2 groups are replaced by S, which may be straight-chain or branched. It is preferably straight-chain, has 1, 2, 3, 4, 5, 6 or 7 C atoms and correspondingly preferably represents thiomethyl, thioethyl, thiopropyl, thiobutyl, thiopentyl, thiohexyl or thioheptyl.

[0080] Oxaalkyl preferably represents straight-chain 2-oxapropyl (=methoxymethyl), 2-oxabutyl (=ethoxymethyl) or 3-oxabutyl (=2-methoxyethyl), 2-, 3- or 4-oxapentyl, 2-, 3-, 4- or 5-oxahexyl, 2-, 3-, 4-, 5- or 6-oxaheptyl, 2-, 3-, 4-, 5-, 6- or 7-oxaoctyl, 2-, 3-, 4-, 5-, 6-, 7- or 8-oxanononyl, 2-, 3-, 4-, 5-, 6-, 7-, 8- or 9-oxadecyl.

[0081] If the group R 1-13 ,R 51 ,R 52 ,R Q ,R,R 2A,R 2B ,R IIIA ,R 1N ,R 2N ,R B1 ,R B2 ,R CR1 ,R CR2 , R or L represents an alkoxy group or an oxaalkyl group, it may also contain one or more additional oxygen atoms, provided that the oxygen atoms are not directly bonded to each other.

[0082] In another preferred embodiment, R 1-13 ,R 51 ,R 52 ,R Q ,R,R 2A ,R 2B ,R IIIA ,R 1N ,R 2N ,R B1 ,R B2 ,R CR1 ,R CR2 , one or more of R or L is selected from the following groups

[0083] -S 1 -F, -OS 1 -F, -O-S1-O-S2, where S 1 C 1-12 -alkylene or C 2-12 -Alkenylene and S 2 H, C 1-12 -alkyl or C 2-12 -alkenyl, and very preferably selected from the following groups

[0084] -OCH2OCH3, -O(CH2)2OCH3, -O(CH2)3OCH3, -O(CH2)4OCH3, -O(CH2)2F, -O(CH2)3F, -O(CH2)4F.

[0085] If the group R 1-13 ,R 51 ,R 52 ,R Q ,R,R 2A ,R 2B ,R IIIA ,R 1N ,R 2N ,R B1 ,RB2 ,R CR1 ,R CR2 , R or L represents an alkyl radical in which one CH2 group has been replaced by -CH=CH-, which may be straight-chain or branched. It is preferably straight-chain and has 2 to 10 C atoms. Accordingly, it represents, in particular, 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, oct-1-, -2-, -3-, -4-, -5-, -6- or -7-enyl, non-1-, -2-, -3-, -4-, -5-, -6-, -7- or -8-enyl, dec-1-, -2-, -3-, -4-, -5-, -6-, -7-, -8- or -9-enyl.

[0086] If the group R 1-13 ,R 51 ,R 52 ,R Q ,R,R 2A ,R 2B ,R IIIA ,R 1N ,R 2N ,R B1 ,R B2 ,R CR1 ,R CR2 , R or L represents an alkyl or alkenyl group which is at least monosubstituted by halogen, the group is preferably linear, and the halogen is preferably F or Cl. In the case of polysubstitution, the halogen is preferably F. The resulting groups also include perfluorinated groups. In the case of monosubstitution, the fluorine or chlorine substituent may be in any desired position, but preferably in the ω-position.

[0087] Halogen is preferably F or Cl, very preferably F.

[0088] Group-CR 0 =CR 00 -Preferably -CH=CH-.

[0089] -CO-, -C(=O)- and -C(O)- represent carbonyl groups, i.e.

[0090] Preferred substituents L are, for example, F, Cl, Br, I, -CN, -NO2, -NCO, -NCS, -OCN, -SCN, -C(=O)N(R x )2, -C(=O)Y 1 、-C(=O)R x 、-N(R x) 2, straight-chain or branched alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy, each having 1 to 25 C atoms, wherein one or more H atoms may be optionally replaced by F or Cl, optionally substituted silyl having 1 to 20 Si atoms, or optionally substituted aryl having 6 to 25, preferably 6 to 15 C atoms,

[0091] Where R x represents H, F, Cl, CN, or a straight-chain, branched or cyclic alkyl group having 1 to 25 C atoms, wherein one or more non-adjacent CH2 groups are optionally replaced by -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O- in such a way that the O- and / or S-atoms are not directly connected to each other, and wherein one or more H atoms are each optionally replaced by F, Cl, P- or P-Sp-, and

[0092] Y 1 Represents halogen.

[0093] Particularly preferred substituents L are, for example, F, Cl, CN, NO2, CH3, C2H5, OCH3, OC2H5, COCH3, COC2H5, COOCH3, COOC2H5, CF3, OCF3, OCHF2, OC2F5, and phenyl.

[0094] Preferably

[0095] wherein L has one of the meanings as stated above.

[0096] The polymerizable group P is a group suitable for polymerization, such as free radical or ionic chain polymerization, addition polymerization or condensation polymerization, or a group suitable for polymer-analogous reactions, such as addition or condensation on the polymer backbone. Particularly preferred are groups for chain polymerization, in particular those containing a C=C double bond or a -C≡C- triple bond, and groups suitable for ring-opening polymerization, such as an oxetane group or an epoxy group.

[0097] Preferred groups P are selected from the following groups

[0098] CH2=CW 1 -CO-O-, CH2=CW 1 -CO-,

[0099] CH2=CW 2 -(O) k3 -、CW 1 =CH-CO-(O) k3 -、CW 1=CH-CO-NH-, CH2=CW 1 -CO-NH-, CH3-CH=CH-O-, (CH2=CH)2CH-OCO-, (CH2=CH-CH2)2CH-OCO-, (CH2=CH)2CH-O-, (CH2=CH-CH2)2N-, (CH2=CH-CH2)2N-CO-, HO-CW 2 W 3 -、HS-CW 2 W 3 -、HW 2 N-、HO-CW 2 W 3 -NH-, CH2=CW 1 -CO-NH-, CH2=CH-(COO) k1 -Phe-(O) k2 -、CH2=CH-(CO) k1 -Phe-(O) k2 -, Phe-CH=CH-, HOOC-, OCN- and W 4 W 5 W 6 Si-, where W 1 represents H, F, Cl, CN, CF3, phenyl or alkyl having 1 to 5 C atoms, in particular H, F, Cl or CH3, W 2 and W 3 each independently of one another represents H or alkyl having 1 to 5 C atoms, in particular H, methyl, ethyl or n-propyl, W 4 ,W 5 and W 6 Each independently represents Cl, oxaalkyl or oxacarbonylalkyl having 1 to 5 C atoms, W 7 and W 8 Each independently represents H, Cl or an alkyl group having 1 to 5 C atoms, Phe represents 1,4-phenylene, which is optionally substituted by one or more groups L different from P-Sp- as defined above, k1, k2 and k3 each independently represent 0 or 1, k3 preferably represents 1, and k4 represents an integer from 1 to 10.

[0100] Very preferred groups P are selected from the following groups:

[0101] CH2=CW 1 -CO-O-, CH2=CW 1 -CO-,

[0102] CH2=CW 2 -O-, CH2=CW2 -、CW 1 =CH-CO-(O) k3 -、CW 1 =CH-CO-NH-, CH2=CW 1 -CO-NH-, (CH2=CH)2CH-OCO-, (CH2=CH-CH2)2CH-OCO-, (CH2=CH)2CH-O-, (CH2=CH-CH2)2N-, (CH2=CH-CH2)2N-CO-, CH2=CW 1 -CO-NH-, CH2=CH-(COO) k1 -Phe-(O) k2 -、CH2=CH-(CO) k1 -Phe-(O) k2 -, Phe-CH=CH- and W 4 W 5 W 6 Si-, where W 1 represents H, F, Cl, CN, CF3, phenyl or alkyl having 1 to 5 C atoms, in particular H, F, Cl or CH3, W 2 and W 3 each independently of one another represents H or alkyl having 1 to 5 C atoms, in particular H, methyl, ethyl or n-propyl, W 4 ,W 5 and W 6 Each independently represents Cl, oxaalkyl or oxacarbonylalkyl having 1 to 5 C atoms, W 7 and W 8 Each independently represents H, Cl or an alkyl group having 1 to 5 C atoms, Phe represents 1,4-phenylene, k1, k2 and k3 each independently represent 0 or 1, k3 preferably represents 1, and k4 represents an integer of 1-10.

[0103] Very particularly preferred groups P are selected from the group CH2=CW 1 -CO-O-, in particular CH2=CH-CO-O-, CH2=C(CH3)-CO-O- and CH2=CF-CO-O-, as well as CH2=CH-O-, (CH2=CH)2CH-O-CO-, (CH2=CH)2CH-O-,

[0104]

[0105] Further preferred polymerizable groups P are selected from vinyloxy, acrylate, methacrylate, fluoroacrylate, chloroacrylate, oxetanyl and epoxy groups, with acrylate and methacrylate being most preferred.

[0106] Very preferably, all polymerizable groups in the polymerizable compound have the same meaning.

[0107] If the spacer group Sp is different from a single bond, it is preferably of the formula Sp"-X", so that each group P-Sp- conforms to the formula P-Sp"-X"-, where

[0108] Sp" denotes a linear or branched alkylene radical having 1 to 20, preferably 1 to 12 C atoms, which is optionally mono- or polysubstituted by F, Cl, Br, I or CN and in which, in addition, one or more non-adjacent CH2 groups may each be independently of one another by -O-, -S-, -NH-, -N(R)-, -S-, -NH-, -NH- or -N(R)- in such a way that the O and / or S atoms are not directly bonded to one another. 0 )-、-Si(R 0 R 00 )-, -CO-, -CO-O-, -O-CO-, -O-CO-O-, -S-CO-, -CO-S-, -N(R 00 )-CO-O-、-O-CO-N(R 0 )-、-N(R 0 )-CO-N(R 00 )-, -CH=CH- or -C≡C-,

[0109] X" means -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O-, -CO-N(R 0 )-、-N(R 0 )-CO-、-N(R 0 )-CO-N(R 00 )-, -OCH2-, -CH2O-, -SCH2-, -CH2S-, -CF2O-, -OCF2-, -CF2S-, -SCF2-, -CF2CH2-, -CH2CF2-, -CF2CF2-, -CH=N-, -N=CH-, -N=N-, -CH=CR 0 -、-CY 2 =CY 3 -, -C≡C-, -CH=CH-CO-O-, -O-CO-CH=CH- or a single bond,

[0110] R 0 and R 00 each independently of one another represents H or an alkyl group having 1 to 20 C atoms, and

[0111] Y 2 and Y 3 Each independently of one another represents H, F, Cl or CN.

[0112] X" is preferably -O-, -S-, -CO-, -COO-, -OCO-, -O-COO-, -CO-NR 0 -、-NR 0 -CO-、-NR 0 -CO-NR 00 - or single key.

[0113] Typical spacer groups Sp and -Sp"-X"- are, for example, -(CH2) p1 -、-(CH2) p1 -O-, -(CH2) p1 -O-CO-, -(CH2) p1 -CO-O-, -(CH2) p1 -O-CO-O-, -(CH2CH2O) q1 -CH2CH2-, -CH2CH2-S-CH2CH2-, -CH2CH2-NH-CH2CH2- or -(SiR 0 R 00 -O) p1 -, wherein p1 is an integer from 1 to 12, q1 is an integer from 1 to 3, and R 0 and R 00 Has the meaning as stated above.

[0114] Particularly preferred groups Sp and -Sp"-X"- are -(CH2) p1 -、-(CH2) p1 -O-, -(CH2) p1 -O-CO-, -(CH2) p1 -CO-O-, -(CH2) p1 -O-CO-O-, wherein p1 and q1 have the meanings as defined above.

[0115] Particularly preferred radicals Sp" are in each case linear ethylene, propylene, butylene, pentylene, hexylene, heptylene, octylene, nonylene, decylene, undecylene, dodecylene, octadecylene, ethyleneoxyethylene, methyleneoxybutylene, ethylenethioethylene, ethylene-N-methyliminoethylene, 1-methylalkylene, vinylene, propenylene and butenylene.

[0116] In a preferred embodiment of the invention, the compounds of formula I and its subformulae contain a spacer group Sp substituted by one or more polymerizable groups P, such that the group Sp-P corresponds to Sp(P)s , wherein s is ≥ 2 (branched polymerizable group).

[0117] Preferred compounds of formula I according to this preferred embodiment are those wherein s is 2, ie compounds containing the group Sp(P)2. Very preferred compounds of formula I according to this preferred embodiment contain a group selected from the following formulae:

[0118] -X-alkyl-CHPP S1

[0119] -X-alkyl-CH((CH2) aa P)((CH2) bb P) S2

[0120] -XN((CH2) aa P)((CH2) bb P) S3

[0121] -X-alkyl-CHP-CH2-CH2P S4

[0122] -X-alkyl-C(CH2P)(CH2P)-C aa H 2aa+1 S5

[0123] -X-alkyl-CHP-CH2P S6

[0124] -X-alkyl-CPP-C aa H 2aa+1 S7

[0125] -X-alkyl-CHPCHP-C aa H 2aa+1 S8

[0126] Wherein P is defined as Formula I,

[0127] Alkyl represents a single bond or a straight-chain or branched alkylene radical having 1 to 12 C atoms, which is unsubstituted or mono- or polysubstituted by F, Cl or CN and in which one or more non-adjacent CH2 groups may each independently of one another be substituted by -C(R) in such a way that the O and / or S atoms are not directly bonded to one another. 0 )=C(R 0 )-、-C≡C-、-N(R 0 )-, -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O- substitution, where R 0 has the meaning as stated above,

[0128] aa and bb each independently represent 0, 1, 2, 3, 4, 5 or 6,

[0129] X has one of the meanings given for X" and is preferably O, CO, SO2, O-CO-, CO-O or a single bond.

[0130] Preferred spacer groups Sp(P)2 are selected from the group consisting of formulae S1, S2 and S3.

[0131] Very preferred spacer groups Sp(P)2 are selected from the following sub-formulae:

[0132] -CHPP S1a

[0133] -O-CHPP S1b

[0134] -CH2-CHPP S1c

[0135] -OCH2-CHPP S1d

[0136] -CH(CH2-P)(CH2-P) S2a

[0137] -OCH(CH2-P)(CH2-P) S2b

[0138] -CH2-CH(CH2-P)(CH2-P) S2c

[0139] -OCH2-CH(CH2-P)(CH2-P) S2d

[0140] -CO-NH((CH2)2P)((CH2)2P) S3a

[0141] P is preferably selected from vinyloxy, acrylate, methacrylate, fluoroacrylate, chloroacrylate, oxetanyl and epoxy, very preferably acrylate and methacrylate, most preferably methacrylate.

[0142] It is further preferred that all polymerizable groups P present in the same compound have the same meaning and very preferably denote acrylate or methacrylate groups, most preferably methacrylate groups.

[0143] Sp preferably represents a single bond or -(CH2) p1 -、-(CH2) p2 -CH=CH-(CH2) p3 -、-O-(CH2) p1 -、-O-CO-(CH2) p1 , or -CO-O-(CH2) p1 , wherein p1 is 2, 3, 4, 5 or 6, preferably 2 or 3, p2 and p3 are independently 0, 1, 2 or 3 and, if Sp is -O-(CH2) p1-、-O-CO-(CH2) p1 or -CO-O-(CH2) p1 , then the O-atom or CO-group is connected to the benzene ring respectively.

[0144] It is further preferred that at least one group Sp is a single bond.

[0145] It is further preferred that at least one group Sp is different from a single bond and is preferably selected from -(CH2) p1 -、-(CH2) p2 -CH=CH-(CH2) p3 -、-O-(CH2) p1 -、-O-CO-(CH2) p1 , or -CO-O-(CH2) p1 , wherein p1 is 2, 3, 4, 5 or 6, preferably 2 or 3, p2 and p3 are independently 0, 1, 2 or 3 and, if Sp is -O-(CH2) p1 -、-O-CO-(CH2) p1 or -CO-O-(CH2) p1 , then the O-atom or CO-group is connected to the benzene ring respectively.

[0146] Very preferably, Sp is different from a single bond and is selected from -(CH2)2-, -(CH2)3-, -(CH2)4-, -O-(CH2)2-, -O-(CH2)3-, -O-CO-(CH2)2 and -CO-O-(CH)2-, wherein the O atom or the CO group is attached to the benzene ring.

[0147] Preferably, the polymerizable compound having absorption in the range of 340 to 400 nm comprises a terphenyl moiety, and three polymerizable groups attached thereto directly or via a spacer group.

[0148] Very preferably, the polymerizable compound having absorption in the range of 340 to 400 nm is selected from the group consisting of formula I1

[0149]

[0150] The groups are independent of one another and have the following meanings at each occurrence, identically or differently:

[0151] P is a polymerizable group,

[0152] Sp is a spacer or a single bond optionally substituted by one or more groups P,

[0153] L is F, Cl, Br, -CN or a straight-chain, branched or cyclic alkyl radical having 1 to 25 C atoms, wherein one or more non-adjacent CH2 groups are optionally replaced by -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O-, -N(R) in such a way that the O- and / or S-atoms are not directly connected to each other. 0 )-、-Si(R 0 R 00 )-, -CH=CH- or -C≡C-, and wherein one or more H atoms are each optionally replaced by F or Cl,

[0154] r1 and r2 are 0, 1, 2, 3 or 4, preferably 0, 1 or 2,

[0155] r3 is 0, 1, 2 or 3, preferably 0 or 1.

[0156] Preferred compounds of formula I1 are selected from the following sub-formulas

[0157]

[0158] Wherein P, Sp, L, r1, r2 and r3 have one of the meanings given in formula I1 or one of their preferred meanings given above and below, independently of one another. P is preferably an acrylate or methacrylate group, very preferably a methacrylate group. Sp is preferably a single bond. Preferably, all groups P in formulas I1 and I1-1 to I1-3 have the same meaning and very preferably represent a methacrylate group.

[0159] Very preferred are compounds of formula I1-1 and formula I1-2, most preferred are compounds of formula I1-2, and compounds of subformulae thereof.

[0160] Very preferred compounds of formula I1 are selected from the following sub-formula

[0161]

[0162]

[0163]

[0164]

[0165]

[0166]

[0167] wherein P and L have one of the meanings given above and below, and Sp' has one of the meanings given for Sp which is different from a single bond. P is preferably an acrylate or methacrylate group, very preferably a methacrylate group. Preferably, all radicals P in formulae I1-1-1 to I1-3-12 have the same meaning and very preferably represent a methacrylate group. Sp' is preferably selected from -(CH2)2-, -(CH2)3-, -(CH2)4-, -O-(CH2)2-, -O-(CH2)3-, -O-CO-(CH2)2 and -CO-O-(CH)2-, wherein the O atom or the CO group is attached to a benzene ring. L is preferably selected from F, CH3, OCH3, OC2H5, C2H5, CH=CH2 and C(CH3)=CH2, very preferably from F, OCH3 and C2H5.

[0168] Very preferred are compounds of formula I1-1-1, I1-1-2, I1-1-3, I1-1-4, I1-1-5, I1-1-6, I1-1-7, I1-1-8, I1-1-9, I1-1-10, I1-1-11, I1-1-12, I1-2-1, I1-2-2, I1-2-3, I1-2-4, I1-2-5, I1-2-6, I1-2-7, I1-2-8, I1-2-9, I1-2-10, I1-2-11, I1-2-12 and subformulae thereof. Most preferred are compounds of formula I1-2-7, I1-2-8, I1-2-9, I1-2-10, I1-2-11, I1-2-12 and subformulae thereof.

[0169] Very preferred compounds of formula I1 are selected from the following sub-formulae:

[0170]

[0171]

[0172]

[0173]

[0174]

[0175]

[0176]

[0177]

[0178]

[0179]

[0180]

[0181] Very preferred are compounds of formula I1-1-1a, I1-1-2a, I1-1-3a, I1-1-4a, I1-1-5a, I1-1-6a, I1-1-7a, I1-1-7b, I1-1-8a, I1-1-9a, I1-1-10a, I1-1-11a, I1-1-12a, I1-2-1a, I1-2-2a, I1-2-4a, I1-2-5a, I1-2-6a, I1-2-7a, I1-2-7b, I1-2-8a, I1-2-9a, I1-2-10a, I1-2-11a and I1-2-12a. Most preferred are compounds of formula I1-1-7a, I1-1-7b, I1-2-7a and I1-2-7b.

[0182] Further preferred are compounds of the formulae I1-1-1a to I1-3-11a in which one or two methacrylate groups are replaced by acrylate groups, and compounds of the formulae I1-1-1a to I1-3-11a in which all methacrylate groups are replaced by acrylate groups.

[0183] In a preferred embodiment, the LC medium comprises, in addition to the polymerizable compound having absorption in the range from 340 to 400 nm, one or more polymerizable compounds having three polymerizable groups selected from the group consisting of:

[0184]

[0185] wherein P, Sp, L, r1 and r3 have the meanings given in formula I1.

[0186] Preferred compounds of formula I2 are selected from the following sub-formulas

[0187]

[0188]

[0189] Wherein P, Sp, L, r1 and r3 have one of the meanings given in formula I2 or one of their preferred meanings given above and below, independently of one another. P is preferably an acrylate or methacrylate group, very preferably a methacrylate group. Sp is preferably a single bond. Preferably, all groups P in formulas I2 and I2-1 to I2-3 have the same meaning and very preferably represent a methacrylate group.

[0190] Very preferred are compounds of formulae 12-1 and 12-2, most preferred are compounds of formula 12-1, and compounds of subformulae thereof.

[0191] Very preferred compounds of formula I2 are selected from the following sub-formula

[0192]

[0193]

[0194]

[0195]

[0196] wherein P and L have one of the meanings given above and below, and Sp' has one of the meanings given for Sp which is different from a single bond. P is preferably an acrylate or methacrylate group, very preferably a methacrylate group. Preferably, all radicals P in formulae I2-1-1 to I2-3-6 have the same meaning and very preferably represent a methacrylate group. Sp' is preferably selected from -(CH2)2-, -(CH2)3-, -(CH2)4-, -O-(CH2)2-, -O-(CH2)3-, -O-CO-(CH2)2 and -CO-O-(CH)2-, wherein the O atom or the CO group is attached to the benzene ring. L is preferably selected from F, CH3, OCH3, OC2H5, C2H5, CH=CH2 and C(CH3)=CH2, very preferably from F and OCH3.

[0197] Very preferred are compounds of formula I2-1-1, I2-1-2, I2-1-3, I2-2-1, I2-2-2, I2-2-3, I2-3-1, I2-3-2, I2-3-3 and subformulae thereof. Most preferred are compounds of formula I2-1-1, I2-1-2, I2-1-3 and subformulae thereof.

[0198] Very preferred compounds of formula I2 are selected from the following sub-formulae:

[0199]

[0200]

[0201]

[0202]

[0203]

[0204]

[0205]

[0206] Very preferred are compounds of formula I2-1-1a, I2-1-2a, I2-1-2b, I2-2-1a, I2-2-2a, I2-2-2b, I2-3-1a, I2-3-2a and I2-3-2b. Most preferred are compounds of formula I2-1-1a, I2-1-2a, I2-1-2b, I2-2-1a, I2-2-2a and I2-2-2b.

[0207] Further preferred are compounds of the formulae I2-1-1a to I2-3-5a in which one or two methacrylate groups are replaced by acrylate groups, and compounds of the formulae I2-1-1a to I2-3-5a in which all methacrylate groups are replaced by acrylate groups.

[0208] In another preferred embodiment, the LC medium comprises, in addition to the polymerizable compound having absorption in the range from 340 to 400 nm, one or more polymerizable compounds having two polymerizable groups selected from the group consisting of formula I3

[0209]

[0210] wherein P, Sp, L, r1 and r2 have the meanings given in formula I1, and preferably at least one of r1 and r2 is not zero.

[0211] Preferred compounds of formula I3 are selected from the following sub-formulas

[0212]

[0213] Wherein P, Sp, L, r1 and r2 have one of the meanings given in formula I3 or one of their preferred meanings given above and below, and Sp' has one of the meanings given for Sp that is different from a single bond. Preferably, at least one of r1 and r2 is not 0. P is preferably an acrylate or methacrylate group, very preferably a methacrylate group. Preferably, all groups P in formulas I3, I3-1 and I3-2 have the same meaning and very preferably represent a methacrylate group. Sp' is preferably selected from -(CH2)2-, -(CH2)3-, -(CH2)4-, -O-(CH2)2-, -O-(CH2)3-, -O-CO-(CH2)2 and -CO-O-(CH)2-, wherein the O atom or CO group is attached to the benzene ring.

[0214] Very preferred are compounds of formula I3-1.

[0215] More preferred compounds of formula I3 are selected from the following sub-formulas

[0216]

[0217]

[0218] wherein P, Sp' and L have one of the meanings given above and below. P is preferably an acrylate or methacrylate group, very preferably a methacrylate group. Preferably, all groups P in formulae I3-1-1 to I3-2-9 have the same meaning and very preferably represent a methacrylate group. Sp' is preferably selected from -(CH2)2-, -(CH2)3-, -(CH2)4-, -O-(CH2)2-, -O-(CH2)3-, -O-CO-(CH2)2 and -CO-O-(CH)2-, wherein the O atom or the CO group is attached to the benzene ring. L is preferably selected from F, CH3, OCH3, OC2H5, C2H5, CH=CH2 and C(CH3)=CH2, very preferably from F and OCH3.

[0219] Very preferred are compounds of formula I3-1-2, I3-1-3, I3-1-4, I3-1-5, I3-1-6 and subformulae thereof. Most preferred are compounds of formula I3-1-2 and I3-1-3 and subformulae thereof.

[0220] Very preferred compounds of formula I3 are selected from the following sub-formulae:

[0221]

[0222]

[0223]

[0224]

[0225] Very preferred are compounds of formulae I1-1-2a, I1-1-2b, I1-1-3a, I1-1-3b, I1-1-4a, I1-1-4b, I1-1-5a and I1.1-6a. Most preferred are compounds of formulae I1-1-2a, I1-1-2b, I1-1-3a and I1-1-3b.

[0226] Further preferred are compounds of the formulae I3-1-1a to I3-2-9a in which one or two methacrylate groups are replaced by acrylate groups, and compounds of the formulae I3-1-1a to I3-2-9a in which all methacrylate groups are replaced by acrylate groups.

[0227] Further preferred compounds of formula I1, I2, I3, I1-1, I1-2, I1-3, I2-1, I2-2, I2-3, I3-1, I3-2, I1-1-1 to I1-3-12, I2-1-1 to I2-3-6 and I3-1-1 to I3-2-9 are selected from one or more of the following embodiments:

[0228] - the groups P independently of one another represent acrylate or methacrylate groups, very preferably methacrylate groups,

[0229] - all the groups P in a compound have the same meaning,

[0230] -Sp is a single bond,

[0231] at least one, preferably one or two, of the radicals Sp is a single bond and the other radicals Sp are different from single bonds,

[0232] -When Sp is different from a single bond, Sp and Sp' are selected from -(CH2) p1 -、-(CH2) p2 -CH=CH-(CH2) p3 -、-O-(CH2) p1 -、-O-CO-(CH2) p1 or -CO-O-(CH2) p1 , wherein p1 is 2, 3, 4, 5 or 6, preferably 2 or 3, p2 and p3 are independently 0, 1, 2 or 3; and if Sp is -O-(CH2) p1 -、-O-CO-(CH2) p1 or -CO-O-(CH2) p1 , then the O-atom or CO-group is connected to the benzene ring,

[0233] - when Sp is different from a single bond, Sp and Sp' are selected from -(CH2)2-, -(CH2)3-, -(CH2)4-, -O-(CH2)2-, -O-(CH2)3-, -O-CO-(CH2)2 and -CO-O-(CH)2-, wherein the O atom or CO group is attached to the benzene ring,

[0234] -L is selected from F, Cl, Br, CN, alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy, each having 1 to 6 C atoms, or alkenyl having 2 to 6 C atoms, wherein one or more H atoms are optionally replaced by F or Cl,

[0235] -L is selected from F, CH3, OCH3, OC2H5, C2H5, CH=CH2 and C(CH3)=CH2, very preferably selected from F and OCH3.

[0236] For use in PSA displays, the total proportion of polymerizable compounds of the formulae I1, I2 and I3 in the LC medium is preferably from 0.01 to 2.0%, very preferably from 0.1 to 1.0%, most preferably from 0.2 to 0.8%.

[0237] The proportion of the compound of the formula I1 in the LC medium is preferably from 0.1 to 0.7%, very preferably from 0.2 to 0.6%.

[0238] The proportion of the compound of the formula I2 in the LC medium is preferably from 0.05 to 0.5%, very preferably from 0.1 to 0.4%.

[0239] The proportion of the compound of the formula I3 in the LC medium is preferably from 0.01 to 0.4%, very preferably from 0.05 to 0.2%.

[0240] For use in SA-VA displays, the total proportion of polymerizable compounds of the formulae I1, I2 and I3 in the LC medium is preferably >0 to <3%, very preferably >0 to <2%, more preferably 0.05-2.0%, most preferably 0.05-1.0%.

[0241] The compounds of the formulae I1, I2 and I3 can be prepared analogously to methods known to the person skilled in the art and described in standard works of organic chemistry, for example in Houben-Weyl, Methoden der Organischen Chemie [Methods of Organic Chemistry], Thieme-Verlag, Stuttgart.

[0242] For example, acrylates or methacrylates can be prepared by esterification of the corresponding alcohol with an acid derivative, such as (meth)acryloyl chloride or (meth)acrylic anhydride, in the presence of a base such as pyridine or triethylamine, and 4-(N,N-dimethylamino)pyridine (DMAP). Alternatively, esters can be prepared by esterification of the alcohol with (meth)acrylic acid in the presence of a dehydrating agent, such as dicyclohexylcarbodiimide (DCC), N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide (EDC) or N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride according to Steglich and DMAP.

[0243] The invention further relates to an LC medium or an LC display as described above, in which the polymerisable compounds of the formulae I1, I2 and optionally I3 are present in polymerised form.

[0244] The LC display is preferably a PS-VA, PS-IPS, PS-FFS or SA-VA display.

[0245] To produce a PSA or polymer-stabilized SA display, the polymerizable compounds contained in the LC medium are polymerized by in situ polymerization in the LC medium between the substrates of the LC display, preferably while applying a voltage to the electrodes.

[0246] As described in the prior art cited at the outset, the structure of the display according to the invention corresponds to the usual geometries of PSA displays. Preference is given to geometries without protrusions, in particular those in which the electrode on the color filter side is unstructured and only the electrode on the TFT side has slots. Particularly suitable and preferred electrode structures for PS-VA displays are described, for example, in US 2006 / 0066793 A1.

[0247] Preferred LC displays of the PSA type according to the invention comprise:

[0248] a first substrate comprising a pixel electrode defining a pixel area, the pixel electrode being connected to a switching element disposed in each pixel area and optionally comprising a micro-slit pattern, and optionally a first alignment layer disposed on the pixel electrode,

[0249] a second substrate comprising a common electrode layer, which may be arranged on the entire portion of the second substrate facing the first substrate, and optionally a second alignment layer,

[0250] - an LC layer arranged between the first substrate and the second substrate and comprising an LC medium as described above and below, wherein the polymerisable compound may also be present in polymerised form.

[0251] The first and / or second alignment layer controls the alignment direction of the LC molecules of the LC layer. For example, in a PS-VA display, the alignment layer is selected so that it imparts a homeotropic (or vertical) alignment (i.e. perpendicular to the surface) or a tilted alignment to the LC molecules. Such an alignment layer may, for example, comprise polyimide, which may also be rubbed, or may be prepared by a photoalignment method.

[0252] The LC layer with the LC medium can be deposited between the substrates of the display by methods conventionally used by display manufacturers, such as the so-called one-drop-filling (ODF) method. The polymerizable components of the LC medium are then polymerized, for example, by UV photopolymerization. The polymerization can be carried out in one step or in two or more steps.

[0253] The PSA display may include further elements such as colour filters, a black matrix, a passivation layer, an optical retardation layer, transistor elements for addressing the individual pixels etc., which are well known to those skilled in the art and may be used without inventive skill.

[0254] The electrode structure can be designed by technicians according to each display type. For example, for PS-VA displays, multi-domain orientation of LC molecules can be induced by providing electrodes with slits and / or ridges or protrusions to produce two, four or more different tilted alignment directions.

[0255] After polymerization, the polymerizable compound forms a copolymer, which results in a certain tilt angle of the LC molecules in the LC medium. Without wishing to be bound by a particular theory, it is believed that at least a portion of the cross-linked polymer formed by the polymerizable compound will phase separate or precipitate from the LC medium and form a polymer layer on the substrate or electrode, or an alignment layer is provided thereon. Microscopic measurement data (such as SEM and AFM) have confirmed that at least a portion of the formed polymer accumulates at the LC / substrate interface.

[0256] It is also possible to polymerize in a first step to produce the tilt angle, optionally with simultaneous application of a voltage, and then polymerize or crosslink the unreacted compounds of the first step in a second polymerization step without application of a voltage ("final curing").

[0257] Suitable and preferred polymerisation methods are, for example, thermal polymerisation or photopolymerisation, preferably photopolymerisation, in particular UV-induced photopolymerisation, which can be achieved by exposing the polymerisable compound to UV radiation.

[0258] Optionally, one or more polymerization initiators are added to the LC medium. Suitable polymerization conditions and suitable initiator types and amounts are known to the person skilled in the art and are described in the literature. Suitable for free-radical polymerization are, for example, commercially available photoinitiators or (Ciba AG). If a polymerization initiator is used, its proportion is preferably from 0.001 to 5% by weight, particularly preferably from 0.001 to 1% by weight.

[0259] The polymerizable compounds according to the invention are also suitable for polymerization without initiators, which has considerable advantages, for example lower material costs and, in particular, less contamination of the LC medium with possible residual amounts of initiator or its degradation products. Thus, the polymerization can also be carried out without the addition of initiators. Therefore, in a preferred embodiment, the LC medium does not contain a polymerization initiator.

[0260] The LC medium may also contain one or more stabilizers to prevent unwanted spontaneous polymerization of the RM, for example during storage or transport. Suitable types and amounts of stabilizers are known to the person skilled in the art and are described in the literature. Particularly suitable are, for example, Series (Ciba AG) commercially available stabilizers, such as 1076. If stabilizers are used, their proportion, based on the total amount of RM or polymerizable component (component A), is preferably 10 to 50,000 ppm, particularly preferably 50 to 5,000 ppm.

[0261] In a preferred embodiment, the LC medium contains one or more chiral dopants, preferably in a concentration of 0.01 to 1 wt %, very preferably 0.05 to 1.0 wt %. The chiral dopant is preferably selected from the compounds of Table B below, very preferably R- or S-1011, R- or S-2011, R- or S-3011, R- or S-4011 and R- or S-5011.

[0262] In another preferred embodiment, the LC medium contains the racemate of one or more chiral dopants, which are preferably selected from the chiral dopants mentioned in the previous paragraph.

[0263] In a further preferred embodiment of the present invention the LC medium contains one or more further stabilizers, preferably selected from the group consisting of

[0264]

[0265] where the radicals are independent of one another and have the following meanings on each occurrence, identically or differently:

[0266] R a-d is a straight-chain or branched alkyl radical having 1 to 10, preferably 1 to 6, very preferably 1 to 4 C atoms, most preferably methyl,

[0267] X S H, CH3, OH or O ● ,

[0268] A S is a straight-chain, branched or cycloalkylene radical having 1 to 20 C atoms, which is optionally substituted,

[0269] n is an integer of 1-6, preferably 3.

[0270] Preferred stabilizers of formula S3 are selected from formula S3A

[0271]

[0272] wherein n2 is an integer from 1 to 12, and wherein the group (CH2) n2 One or more H atoms in the group are optionally replaced by methyl, ethyl, propyl, butyl, pentyl or hexyl.

[0273] Very preferred stabilizers are selected from the following formula

[0274]

[0275]

[0276]

[0277] In a preferred embodiment, the liquid-crystalline medium comprises one or more stabilizers selected from the group consisting of formulae S1-1, S2-1, S3-1, S3-1 and S3-3.

[0278] In a preferred embodiment, the liquid-crystalline medium comprises one or more stabilizers selected from Table C below.

[0279] Preferably, the proportion of stabilizers, such as those of the formulae S1 to S3, in the liquid-crystalline medium is from 10 to 500 ppm, very preferably from 20 to 100 ppm.

[0280] In another preferred embodiment, the LC media according to the invention contain a self-aligning (SA) additive, preferably in a concentration of 0.1-2.5%.

[0281] In another preferred embodiment, the LC media according to the invention contain a self-aligning (SA) additive, preferably in a concentration of 0.1-2.5%.

[0282] In a preferred embodiment, the SA-VA display according to the invention does not contain a polyimide alignment layer. In another preferred embodiment, the SA-VA display according to the preferred embodiment contains a polyimide alignment layer.

[0283] Preferred SA additives for this preferred embodiment are selected from compounds comprising a mesogenic group and a linear or branched alkyl side chain terminated by one or more polar anchoring groups selected from hydroxyl, carboxyl, amino or thiol groups.

[0284] Further preferred SA additives contain one or more polymerisable groups, which are optionally linked to the mesogenic group via a spacer group.These polymerisable SA additives can be polymerised in the LC medium under similar conditions as used for RMs in the PSA process.

[0285] Suitable SA additives for inducing homeotropic alignment, especially SA additives for SA-VA mode displays are disclosed in, for example, US 2013 / 0182202 A1, US 2014 / 0838581 A1, US 2015 / 0166890 A1, and US 2015 / 0252265 A1.

[0286] In another preferred embodiment, the LC media or polymer-stabilised SA-VA displays according to the invention contain one or more self-aligning additives selected from Table E below.

[0287] In another preferred embodiment, the LC media according to the invention contain one or more SA additives, preferably of formula II or a subformulae thereof or selected from Table E, in a concentration of 0.1-5%, very preferably 0.2-3%, most preferably 0.2-1.5%.

[0288] The polymerizable compounds of the formulae I1, I2 and I3 do in particular show good UV absorption and are therefore particularly suitable for a process for preparing PSA displays which comprises one or more of the following features:

[0289] - in a two-step process, the polymerizable medium is exposed to UV light in a display, the method comprising a first UV exposure step ("UV1 step"), with application of a voltage to produce the tilt angle, and a second UV exposure step ("UV2 step"), with no application of a voltage to complete the polymerization,

[0290] - Preferably at least in the UV2 step, more preferably in both the UV1 and UV2 steps, the polymerizable medium is exposed to UV light generated by UV-LED lamps in the display.

[0291] The polymerizable medium is exposed in the display to UV light generated by a UV lamp whose irradiation spectrum is shifted to longer wavelengths, preferably ≥340 nm, more preferably 350 to <370 nm, very preferably 355-368 nm, in order to avoid short-term UV light exposure in the PS-VA process.

[0292] Using lower intensities and shifting the UV to longer wavelengths both protect the organic layers from damage that could be caused by UV light.

[0293] A preferred embodiment of the present invention relates to a method for producing a PSA display as described above and below, which method comprises one or more of the following features:

[0294] - irradiating the polymerisable LC medium with UV light in a 2-step process comprising a first UV exposure step ("UV1 step"), with application of a voltage to produce the tilt angle, and a second UV exposure step ("UV2 step"), without application of a voltage to complete the polymerisation,

[0295] - Use intensity of 0.5mW / cm 2 -10 mW / cm 2 , irradiating the polymerizable LC medium with UV light generated by a UV lamp having a wavelength of 300 to 380 nm, preferably in a UV2 step, and optionally also in a UV1 step,

[0296] - irradiating the polymerizable LC medium with UV light of a wavelength ≥ 340 nm and preferably ≤ 420 nm, very preferably 340-380 nm, more preferably 350 to < 370 nm, most preferably 355-368 nm,

[0297] - irradiating the polymerizable LC medium with UV light while applying a voltage to the electrodes of the display,

[0298] -UV light irradiation using UV-LED lamp.

[0299] For example, the preferred method can be performed by using a desired UV lamp or by using a bandpass filter and / or a cutoff filter that is substantially transmissive to UV light having each desired wavelength and substantially blocking each undesired wavelength. For example, when irradiation with UV light having a wavelength λ of 300-400 nm is required, a broadband filter that is substantially transmissive to a wavelength of 300 nm <λ <400 nm can be used for UV exposure. When irradiation with UV light having a wavelength λ greater than 340 nm is required, a cutoff filter that is substantially transmissive to a wavelength of λ>340 nm can be used for UV irradiation.

[0300] Preferably, UV-LED lamps are used for UV irradiation.

[0301] In the PSA process, the use of UV-LED lamps with only one narrow emission peak offers several advantages, such as more efficient transfer of light energy to the polymerizable compounds in the LC medium, depending on the selection of suitable polymerizable compounds that show absorption at the LED lamp emission wavelength. This allows a reduction in UV intensity and / or UV irradiation time, thus enabling shorter cycle times and saving energy and production costs. Another advantage is that the narrow emission spectrum of the lamp makes it easier to select a suitable wavelength for photopolymerization.

[0302] Very preferably, the UV light source is a UV-LED lamp emitting at a wavelength of 340-400 nm, more preferably 340-380 nm, more preferably 350 to <370 nm, most preferably 355-368 nm. Especially preferred is a UV-LED lamp emitting UV light at a wavelength of 365 nm.

[0303] Preferably, the UV-LED lamp emits light having an emission peak having a full width at half maximum (FWHM) of 30 nm or less.

[0304] UV-LED lamps are commercially available from, for example, Dr. Hoenle AG, Germany or Primelite GmbH, Germany or IST Metz GmbH, Germany, with emission wavelengths of, for example, 365, 385, 395 and 405 nm.

[0305] This preferred method enables the manufacture of displays by using longer UV wavelengths, thereby reducing or even avoiding the harmful and damaging effects of the short UV light component.

[0306] UV irradiation energy is usually 6-100J, depending on the production process conditions.

[0307] The LC media of the present invention may additionally comprise one or more other components or additives, preferably selected from the following list including, but not limited to, comonomers, chiral dopants, polymerization initiators, inhibitors, stabilizers, surfactants, wetting agents, lubricants, dispersants, hydrophobic agents, binders, flow improvers, defoamers, deaerators, diluents, reactive diluents, auxiliaries, colorants, dyes, pigments and nanoparticles.

[0308] The LC medium preferably has a nematic LC phase.

[0309] In a further preferred embodiment, the LC medium comprises, in addition to the polymerizable compounds of the formulae I1, I2 and I3, one or more further polymerizable compounds ("comonomers"), which are preferably selected from RM.

[0310] Suitable and preferred mesogenic comonomers are selected from the following formula:

[0311]

[0312]

[0313]

[0314]

[0315]

[0316] The radicals in each case have the following meanings, identically or differently and independently of one another, at each occurrence:

[0317] P 1 ,P 2 ,P 3 is a polymerizable group, preferably selected from vinyloxy, acrylate, methacrylate, fluoroacrylate, chloroacrylate, oxetanyl and epoxy groups,

[0318] Sp 1 ,Sp 2 ,Sp 3 is a single bond or a spacer group, wherein in addition, P 1 -Sp 1 -、P 2 -Sp 2 - and P 3 -Sp 3 - One or more groups in may represent R aa , the condition is that the existence of P 1 -Sp 1 -、P 2 -Sp 2 and P 3-Sp 3 -At least one group in it is different from R aa , preferably -(CH2) p1 -、-(CH2) p1 -O-, -(CH2) p1 -CO-O- or -(CH2) p1 -O-CO-O-, wherein p1 is an integer from 1 to 12,

[0319] R aa is H, F, Cl, CN or a straight-chain or branched alkyl radical having 1 to 25 C atoms, wherein in addition, one or more non-adjacent CH2 groups may each be independently of one another in such a way that the O and / or S atoms are not directly connected to one another by -C(R 0 )=C(R 00 )-、-C≡C-、-N(R 0 )-, -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O-, and wherein in addition, one or more H atoms may be replaced by F, Cl, CN or P 1 -Sp 1 - is substituted, particularly preferably with a straight-chain or branched, optionally mono- or polyfluorinated alkyl, alkoxy, alkenyl, alkynyl, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy radical having 1 to 12 C atoms, wherein alkenyl and alkynyl radicals have at least two C atoms and branched radicals have at least three C atoms, and wherein R aa Does not represent or contain group P 1 , P 2 or P 3 ,

[0320] R 0 ,R 00 is H or an alkyl group having 1 to 12 C atoms,

[0321] R y and R z is H, F, CH3 or CF3,

[0322] X 1 ,X 2 ,X 3 is -CO-O-, -O-CO- or a single bond,

[0323] Z M1 -O-, -CO-, -C(R y R z )- or -CF2CF2-,

[0324] Z M2 ,Z M3-CO-O-, -O-CO-, -CH2O-, -OCH2-, -CF2O-, -OCF2- or -(CH2) n -, where n is 2, 3 or 4,

[0325] L is F, Cl, CN or a straight-chain or branched, optionally mono- or polyfluorinated alkyl, alkoxy, alkenyl, alkynyl, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy radical having 1 to 12 C atoms,

[0326] L', L" are H, F or Cl,

[0327] k is 0 or 1,

[0328] r is 0, 1, 2, 3, or 4,

[0329] s is 0, 1, 2, or 3,

[0330] t is 0, 1, or 2,

[0331] x is either 0 or 1.

[0332] Very preferred are compounds of the formulae M2 and M13, especially those containing exactly two polymerizable groups P 1 and P 2 of bi-reactive compounds.

[0333] Further preferred are compounds selected from the group consisting of formulae M17 to M32, in particular formulae M20, M22, M24, M27, M30 and M32, especially those containing exactly three polymerizable groups P 1 , P 2 and P 3 of tri-reactive compounds.

[0334] In the compounds of formula M1-M31

[0335] Preferably

[0336] in which L has, at each occurrence, identically or differently, one of the meanings given above and below, and is preferably F, Cl, CN, NO2, CH3, C2H5, C(CH3)3, CH(CH3)2, CH2CH(CH3)C2H5, OCH3, OC2H5, COCH3, COC2H5, COOCH3, COOC2H5, CF3, OCF3, OCHF2, OC2F5 or P-Sp-, very preferably F, Cl, CN, CH3, C2H5, OCH3, COCH3, OCF3 or P-Sp-, more preferably F, Cl, CH3, OCH3, COCH3 or OCF3 and most preferably F or OCH3.

[0337] Preferred compounds of formula M1-M32 are those wherein P 1 , P 2 and P 3 Those representing acrylate, methacrylate, oxetanyl or epoxy groups, very preferably acrylate or methacrylate, most preferably methacrylate.

[0338] Further preferred compounds of formula M1-M32 are those wherein Sp 1 、Sp 2 and Sp 3 Those that are single bonds.

[0339] Further preferred compounds of formula M1-M32 are those wherein Sp 1 、Sp 2 and Sp 3 One of them is a single bond and Sp 1 、Sp 2 and Sp 3 Another one different from those of single bonds.

[0340] Further preferred compounds of the formulae M1-M32 are those in which the radical Sp which is different from a single bond is 1 、Sp 2 and Sp 3 Represents -(CH2) s1 Those of -X"-, wherein s1 is an integer from 1 to 6, preferably 2, 3, 4 or 5, and X" is a connection to the benzene ring and is -O-, -O-CO-, -CO-O, -O-CO-O- or a single bond.

[0341] Further preferred compounds of formula M are those selected from Table D below, in particular those selected from formula RM-1, RM-4, RM-8, RM-17, RM-19, RM-35, RM-37, RM-39, RM-40, RM-41, RM-48, RM-52, RM-54, RM-57, RM-64, RM-74, RM-76, RM-88, RM-92, RM-102, RM-103, RM-109, RM-116, RM-117, RM-120, RM-121, RM-122, RM-139, RM-142, RM-153, RM-155, RM-158 and RM-159.

[0342] Particular preference is given to LC media which comprise one, two or three polymerisable compounds of the formula M.

[0343] Preference is further given to LC media comprising two or more bireactive polymerizable compounds of the formula M, preferably selected from the formulae M1 to M16, very preferably from the formulae M2 and M13.

[0344] Further preference is given to LC media comprising one or more bireactive polymerizable compounds of the formula M, preferably selected from the group consisting of formulae M1 to M16, very preferably formulae M2 and M13, and one or more trireactive polymerizable compounds of the formula M, preferably selected from the group consisting of formulae M17 to M32, very preferably formulae M20, M22, M24, M27, M30 and M32.

[0345] Further preferred are LC media comprising one or more polymerizable compounds of formula M, wherein at least one r is different from 0, or at least one of s and t is different from 0, very preferably selected from formulae M2, M13, M22, M24, M27, M30 and M32, and wherein L is selected from the preferred groups indicated above, most preferably F and OCH3.

[0346] Further preferred are polymerizable compounds showing absorption in the wavelength range from 320 to 380 nm, preferably selected from formula M, very preferably from formulae M1 to M32, most preferably from the above formulae in Table D.

[0347] In addition to the above-mentioned polymerizable compounds, the LC medium for use in the LC displays of the invention also comprises an LC mixture ("host mixture") comprising one or more, preferably two or more, LC compounds selected from non-polymerizable low molecular weight compounds, of which at least one is a compound of formula II. These LC compounds are selected such that they are stable and / or unreactive towards polymerization reactions under the polymerization conditions applied to the polymerizable compounds.

[0348] Particularly preferred embodiments of such LC media are shown below.

[0349] Preferably, the LC medium contains one or more compounds of formula II selected from compounds of formula IIA, IIB, IIC and IID

[0350]

[0351]

[0352] in

[0353] R 2A and R 2B each independently of one another represents H, alkyl or alkenyl with up to 15 C atoms, which is unsubstituted, monosubstituted by CN or CF3 or at least monosubstituted by halogen, wherein in addition one or more CH2 groups in these radicals can be replaced by -O-, -S ... -C≡C-, -CF2O-, -OCF2-, -OC-O- or -O-CO-,

[0354] L 1 -L 4 each independently represents F, Cl, CF3 or CHF2,

[0355] Y represents H, F, Cl, CF3, CHF2 or CH3, preferably H or CH3, particularly preferably H,

[0356] Z 2 ,Z 2B and Z 2D each independently represents a single bond, -CH2CH2-, -CH=CH-, -CF2O-, -OCF2-, -CH2O-, -OCH2-, -COO-, -OCO-, -C2F4-, -CF=CF-, -CH=CHCH2O-,

[0357] p represents 0, 1, or 2, and

[0358] Each time q appears, it represents 0 or 1, either identically or differently.

[0359] Preferred compounds of formula IIA, IIB, IIC and IID are those wherein R 2B Those representing alkyl or alkoxy groups having up to 15 C atoms and very preferably representing (O)C v H 2v+1 , wherein (O) is an oxygen atom or a single bond and v is 1, 2, 3, 4, 5 or 6.

[0360] Further preferred compounds of formula IIA, IIB, IIC and IID are those wherein R 2A or R 2B Those representing or containing cycloalkyl or cycloalkoxy groups, preferably selected from

[0361] Where S 1 C 1-5 -alkylene or C 2-5 -Alkenylene and S 2 H, C 1-7 -alkyl or C 2-7 -alkenyl, and very preferably selected from

[0362] Further preferred compounds of formula IIA, IIB, IIC and IID are shown below:

[0363]

[0364]

[0365]

[0366]

[0367]

[0368]

[0369]

[0370]

[0371]

[0372]

[0373] The parameter a represents 1 or 2, alkyl and alkyl * each independently of one another represents a straight-chain alkyl radical having 1 to 6 C atoms, and alkenyl represents a straight-chain alkenyl radical having 2 to 6 C atoms, and (O) represents an oxygen atom or a single bond. Alkenyl preferably represents CH2=CH-, CH2=CHCH2CH2-, CH3-CH=CH-, CH3-CH2-CH=CH-, CH3-(CH2)2-CH=CH-, CH3-(CH2)3-CH=CH- or CH3-CH=CH-(CH2)2-.

[0374] Particularly preferred LC media according to the invention comprise one or more compounds of the formulae IIA-2, IIA-8, IIA-10, IIA-16, II-18, IIA-40, IIA-41, IIA-42, IIA-43, IIB-2, IIB-10, IIB-16, IIC-1 and IID-4.

[0375] The proportion of compounds of the formula IIA and / or IIB in the mixture as a whole is preferably at least 20% by weight.

[0376] In another preferred embodiment, the LC medium comprises one or more compounds of formula III

[0377]

[0378] in

[0379] R 11 and R 12 each independently of one another represents H, alkyl or alkoxy having 1 to 15 C atoms, wherein one or more CH2 groups in these groups can each independently of one another be separated in such a way that the O atoms are not directly connected to one another -C≡C-, -CF2O-, -OCF2-, -CH=CH-, replaced by -O-, -CO-O- or -O-CO-, and wherein, in addition, one or more H atoms may be replaced by halogen,

[0380] A 3 Each occurrence represents independently of each other

[0381] a) 1,4-cyclohexenyl or 1,4-cyclohexylene, in which one or two non-adjacent CH2 groups may be replaced by -O- or -S-,

[0382] b) 1,4-phenylene, in which one or both CH groups may be replaced by N, or

[0383] c) a radical selected from the group consisting of spiro[3.3]heptane-2,6-diyl, 1,4-bicyclo[2.2.2]octane-2,6-diyl, naphthalene-2,6-diyl, decahydronaphthalene-2,6-diyl, 1,2,3,4-tetrahydronaphthalene-2,6-diyl, phenanthrene-2,7-diyl and fluorene-2,7-diyl,

[0384] wherein the groups a), b) and c) may be substituted singly or polysubstituted by halogen atoms,

[0385] n represents 0, 1 or 2, preferably 0 or 1,

[0386] Z 1 Each occurrence independently represents -CO-O-, -O-CO-, -CF2O-, -OCF2-, -CH2O-, -OCH2-, -CH2-, -CH2CH2-, -(CH2)4-, -CH=CH-CH2O-, -C2F4-, -CH2CF2-, -CF2CH2-, -CF=CF-, -CH=CF-, -CF=CH-, -CH=CH-, -C≡C- or a single bond, and

[0387] L 11 and L 12 each independently of one another represents F, Cl, CF3 or CHF2, preferably H or F, most preferably F, and

[0388] W represents O or S.

[0389] In a preferred embodiment of the present invention, the LC medium comprises one or more compounds of the formula III-1 and / or III-2

[0390]

[0391]

[0392] The radicals occurring therein have the same meanings as given above under formula III and are preferably

[0393] R 11 and R 12 alkyl, alkenyl or alkoxy, each independently of one another, having up to 15 C atoms, more preferably one or two of them representing alkoxy, and

[0394] L 11 and L 12 Each preferably represents F.

[0395] In another preferred embodiment, the LC medium comprises one or more compounds of the formula III-1 selected from the group consisting of formulae III-1-1 to III-1-10, preferably formula III-1-6,

[0396]

[0397]

[0398] Among them, alkyl and alkyl * each independently of one another represents a straight-chain alkyl radical having 1 to 6 C atoms, alkenyl and alkenyl * each independently of one another represents a straight-chain alkenyl group having 2 to 6 C atoms, alkoxy and alkoxy * each independently represents a straight-chain alkoxy group having 1 to 6 C atoms, and L 11 and L 12 Each independently represents F or Cl, preferably both represent F.

[0399] In another preferred embodiment, the LC medium comprises one or more compounds of the formula III-2 selected from the group consisting of the formulae III-2-1 to III-2-10, preferably the formula III-2-6,

[0400]

[0401]

[0402] Among them, alkyl and alkyl * each independently of one another represents a straight-chain alkyl radical having 1 to 6 C atoms, alkenyl and alkenyl * each independently of one another represents a straight-chain alkenyl group having 2 to 6 C atoms, alkoxy and alkoxy * each independently represents a straight-chain alkoxy group having 1 to 6 C atoms, and L 11 and L 12 Each independently represents F or Cl, preferably both represent F.

[0403] In another preferred embodiment of the present invention, the LC medium comprises one or more compounds of the formula IIIA-1 and / or IIIA-2

[0404]

[0405]

[0406] Where L 11 and L 12 have the same meanings as given under formula III, (O) represents O or a single bond,

[0407] R IIIA represents an alkyl or alkenyl group having up to 7 C atoms, or a group Cy-C m H 2m+1 -,

[0408] m and n, identically or differently, are 0, 1, 2, 3, 4, 5 or 6, preferably 1, 2 or 3, very preferably 1, and

[0409] Cy denotes a cycloaliphatic radical having 3, 4 or 5 ring atoms, which is optionally substituted with alkyl or alkenyl having up to 3 C atoms each, or with halogen or CN, and preferably denotes cyclopropyl, cyclobutyl or cyclopentyl.

[0410] The compounds of the formula IIIA-1 and / or IIIA-2 can be contained in the LC medium instead of the compound of the formula III or in addition, preferably in addition.

[0411] Highly preferred compounds of formula IIIA-1 and IIIA-2 are as follows:

[0412]

[0413]

[0414] Here, alkoxy represents a straight-chain alkoxy group having 1 to 6 C atoms.

[0415] In a preferred embodiment of the present invention, the LC medium comprises one or more compounds of formula III-3

[0416]

[0417] in

[0418] R 11 ,R 12Identically or differently represent H, alkyl or alkoxy groups having 1 to 15 C atoms, wherein one or more CH2 groups in these groups are optionally independently of one another in such a way that the O atoms are not directly connected to one another by -C≡C-, -CF2O-, -OCF2-, -CH=CH-, -O-, -CO-O- or -O-CO-, and wherein, in addition, one or more H atoms may be replaced by halogen.

[0419] The compound of formula III-3 is preferably selected from formulae III-3-1 to III-3-10:

[0420]

[0421]

[0422] Where R 12 represents alkyl having 1 to 7 C atoms, preferably ethyl, n-propyl or n-butyl, or alternatively cyclopropylmethyl, cyclobutylmethyl or cyclopentylmethyl.

[0423] In another preferred embodiment of the present invention, the LC medium comprises one or more compounds of the formulae III-4 to III-6, preferably formula III-5,

[0424]

[0425]

[0426] where the parameters have the meanings given above, R 11 Preferably, it represents a straight chain alkyl group and R 12 Preferably denotes alkoxy radicals, each having 1 to 7 C atoms.

[0427] In another preferred embodiment, the LC medium comprises one or more compounds of the formula III selected from the group consisting of formulae III-7 to III-9, preferably formula III-8,

[0428]

[0429] where the parameters have the meanings given above, R 11 Preferably, it represents a straight chain alkyl group and R 12 Preferably denotes alkoxy radicals, each having 1 to 7 C atoms.

[0430] In a preferred embodiment, the medium comprises one or more compounds of formula IV,

[0431]

[0432] in

[0433] R 41 represents an unsubstituted alkyl group having 1 to 7 C atoms or an unsubstituted alkenyl group having 2 to 7 C atoms, preferably an n-alkyl group, particularly preferably one having 2, 3, 4 or 5 C atoms, and

[0434] R 42 denotes unsubstituted alkyl having 1-7 C atoms or unsubstituted alkoxy having 1-6 C atoms, preferably having 2-5 C atoms, unsubstituted alkenyl having 2-7 C atoms, preferably having 2, 3 or 4 C atoms, more preferably vinyl or 1-propenyl and in particular vinyl.

[0435] The compound of formula IV is preferably selected from formulae IV-1 to IV-4,

[0436]

[0437] in

[0438] Alkyl and alkyl' independently of one another denote an alkyl group having 1 to 7 C atoms, preferably 2 to 5 C atoms,

[0439] Alkenyl is an alkenyl radical having 2 to 5 C atoms, preferably 2 to 4 C atoms, particularly preferably 2 C atoms,

[0440] alkenyl′ denotes alkenyl having 2 to 5 C atoms, preferably having 2 to 4 C atoms, particularly preferably having 2 to 3 C atoms, and

[0441] Alkoxy is an alkoxy group having 1 to 5 C atoms, preferably having 2 to 4 C atoms.

[0442] Preferably, the LC medium comprises one or more compounds selected from the compounds of formulae IV-1-1 to IV-1-6

[0443]

[0444]

[0445] Very preferably, the LC media according to the invention comprise one or more compounds of the formula IV-2-1 and / or IV-2-2

[0446]

[0447] Very preferably, the LC medium according to the invention comprises a compound of the formula IV-3, in particular a compound selected from the group consisting of the formulae IV-3-1 to IV-3-4

[0448]

[0449] Very preferably, the LC medium according to the invention comprises a compound of the formula IV-4, in particular a compound selected from the group consisting of the formulae IV-4-1 and IV-4-2

[0450]

[0451] The LC medium preferably additionally comprises one or more compounds of the formula IVa,

[0452]

[0453] in

[0454] R 41 and R 42 each independently of one another represents straight-chain alkyl, alkoxy, alkenyl, alkoxyalkyl or alkoxy having up to 12 C atoms, and

[0455] express

[0456] Z 4 Represents a single bond, -CH2CH2-, -CH=CH-, -CF2O-, -OCF2-, -CH2O-,

[0457] -OCH2-, -COO-, -OCO-, -C2F4-, -C4H8- or -CF=CF-.

[0458] Preferred compounds of formula IVa are shown below:

[0459]

[0460] Among them, alkyl and alkyl * Each independently of one another represents a straight-chain alkyl radical having 1 to 6 C atoms.

[0461] The LC media according to the invention preferably comprise at least one compound of the formula IVa-1 and / or formula IVa-2.

[0462] The proportion of the compound of the formula IVa in the mixture as a whole is preferably at least 5% by weight.

[0463] Preferably, the LC medium comprises one or more compounds of the formulae IVb-1 to IVb-3

[0464]

[0465] in

[0466] alkyl and alkyl * each independently of one another represents a straight-chain alkyl group having 1 to 6 C atoms, and

[0467] alkenyl and alkenyl * each independently of one another represents a straight-chain alkenyl group having 2 to 6 C atoms.

[0468] The proportion of biphenyls of the formulae IV-1 to IV-3 in the mixture as a whole is preferably at least 3% by weight, in particular ≥5% by weight.

[0469] Among the compounds of formulae IVb-1 to IVb-3, the compound of formula IVb-2 is particularly preferred.

[0470] Particularly preferred biphenyls are

[0471]

[0472] Among them, alkyl * represents alkyl having 1 to 6 C atoms and preferably represents n-propyl.

[0473] The LC media according to the invention particularly preferably comprise one or more compounds of the formula IVb-1-1 and / or IVb-2-3.

[0474] In a preferred embodiment, the LC medium comprises one or more compounds of formula V

[0475]

[0476] in

[0477] R 51 and R 52 Independently of each other, they have 41 and R 42 one of the meanings given and preferably represents alkyl having 1 to 7 C atoms, preferably n-alkyl, particularly preferably n-alkyl having 1 to 5 C atoms, alkoxy having 1 to 7 C atoms, preferably n-alkoxy, particularly preferably n-alkoxy having 2 to 5 C atoms, alkoxyalkyl, alkenyl or alkenyloxy having 2 to 7 C atoms, preferably having 2 to 4 C atoms, preferably alkenyloxy,

[0478] Same or different

[0479]

[0480] in

[0481] Preferred representation

[0482] Z 51 ,Z 52each independently represents -CH2-CH2-, -CH2-O-, -CH=CH-, -C≡C-, -COO- or a single bond, preferably -CH2-CH2-, -CH2-O- or a single bond and particularly preferably a single bond, and

[0483] n is 1 or 2.

[0484] The compound of formula V is preferably selected from the compounds of formulae V-1 to V-16:

[0485]

[0486] Where R 1 and R 2 With the above for R 2A The meaning stated.

[0487] R 1 and R 2 Preferably each independently of one another represents a straight-chain alkyl or alkenyl group.

[0488] Preferred LC media comprise one or more compounds of formula V-1, V-3, V-4, V-6, V-7, V-10, V-11, V-12, V-14, V-15 and / or V-16

[0489] The LC media according to the invention very particularly preferably comprise compounds of the formulae V-10, V-12, V-16 and / or IV-1, in particular in an amount of 5 to 30%.

[0490] Preferred compounds of formula V-10 are shown below:

[0491]

[0492] The LC medium according to the invention particularly preferably comprises a combination of a tricyclic compound of the formula V-10a and / or V-10b with one or more bicyclic compounds of the formula IV-1. The total proportion of the combination of the compounds of the formula V-10a and / or V-10b with one or more compounds selected from the dicyclohexyl compounds of the formula IV-1 is 5 to 40%, very particularly preferably 15 to 35%.

[0493] Very particularly preferred LC media comprise compounds V-10a and CC-2-3

[0494]

[0495] The compounds V-10a and IV-1-1 are preferably present in the mixture in a concentration of 15 to 35%, particularly preferably 15 to 25% and especially preferably 18 to 22%, based on the entire mixture.

[0496] Very particularly preferred LC media comprise compounds V-10b and IV-1-1:

[0497]

[0498] The compounds V-10b and IV-1-1 are preferably present in the mixture in a concentration of 15 to 35%, particularly preferably 15 to 25% and especially preferably 18 to 22%, based on the entire mixture.

[0499] Very particularly preferred LC media comprise the following three compounds:

[0500]

[0501] The compounds V-10a, V-10b and IV-1-1 are preferably present in the mixture in a concentration of 15 to 35%, particularly preferably 15 to 25% and especially preferably 18 to 22%, based on the entire mixture.

[0502] Preferred LC media comprise at least one compound selected from the group consisting of

[0503]

[0504] Where R 41 and R 42 , and R 51 and R 52 Preferably, in compounds V-6, V-7 and IV-1, R 41 and R 51 represents an alkyl or alkenyl group having 1 to 6 C atoms or 2 to 6 C atoms, respectively, and R 42 and R 52 represents an alkenyl group having 2 to 6 C atoms.

[0505] Preferred LC media comprise at least one compound of the formula V-6a, V-6b, V-7a, V-7b, IV-4-1, IV-4-2, IV-3a and IV-3b:

[0506]

[0507]

[0508] Here, alkyl represents an alkyl radical having 1 to 6 C atoms and alkenyl represents an alkenyl radical having 2 to 6 C atoms.

[0509] The compounds of the formulae V-6a, V-6b, V-7a, V-7b, IV-4-1, IV-4-2, IV-3a and IV-3b are preferably present in the LC media according to the invention in an amount of 1 to 40% by weight, preferably 5 to 35% by weight and very particularly preferably 10 to 30% by weight.

[0510] In a preferred embodiment of the present invention, the LC medium additionally comprises one or more compounds of the formulae VI-1 to VI-9

[0511]

[0512]

[0513] in

[0514] R 7 Each independently has for R in Formula IIA 2A one of the meanings, and

[0515] w and x each independently represent 1-6.

[0516] It is particularly preferred that the LC medium comprises at least one compound of the formula V-9.

[0517] In a preferred embodiment of the present invention, the LC medium additionally comprises one or more compounds of the formulae VII-1 to VII-25,

[0518]

[0519]

[0520]

[0521] in

[0522] R represents a straight chain alkyl or alkoxy group having 1 to 6 carbon atoms, (O) represents -O- or a single bond, X represents F, Cl, OCF3 or OCHF2, L x represents H or F, m is 0, 1, 2, 3, 4, 5 or 6 and n is 0, 1, 2, 3 or 4.

[0523] R preferably represents methyl, ethyl, propyl, butyl, pentyl, hexyl, methoxy, ethoxy, propoxy, butoxy or pentyloxy.

[0524] X preferably represents F or OCH3, very preferably F.

[0525] The LC media according to the invention preferably comprise the terphenyls of the formulae VII-1 to VII-25 in an amount of 2 to 30% by weight, in particular 5 to 20% by weight.

[0526] Particularly preferred are compounds of formula VII-1, VII-2, VII-4, VII-20, VII-21, and VII-22, in which X represents F. In these compounds, R preferably represents alkyl, and alkoxy, each having 1 to 5 C atoms. In the compound of formula VII-20, R preferably represents alkyl or alkenyl, in particular alkyl. In the compound of formula VII-21, R preferably represents alkyl. In the compounds of formula VII-22 to VII-25, X preferably represents F.

[0527] Terphenyls of the formulae VII-1 to VII-25 are preferably used in the LC media according to the invention if the Δn value of the mixture is ≥ 0.1. Preferred LC media comprise 2 to 20 wt % of one or more terphenyl compounds selected from the compounds of the formulae VII-1 to VII-25.

[0528] Further preferred embodiments are listed below:

[0529] a) the LC medium comprises at least one compound of the formulae Z-1 to Z-7,

[0530]

[0531]

[0532] wherein R, (O) and alkyl have the meanings as described above for formula III.

[0533] b) Preferred LC media according to the invention comprise one or more substances containing tetrahydronaphthyl or naphthyl units, for example compounds of the formulae N-1 to N-5,

[0534]

[0535] Where R 1N and R 2N Each independently has the above for R 2A The above meanings preferably denote straight-chain alkyl, straight-chain alkoxy or straight-chain alkenyl, and

[0536] Z 1 and Z 2 Each independently represents -C2H4-, -CH=CH-, -(CH2)4-, -(CH2)3O-, -O(CH2)3-, -CH=CHCH2CH2-, -CH2CH2CH=CH-, -CH2O-, -OCH2-, -COO-, -OCO-, -C2F4-, -CF=CF-, -CF=CH-, -CH=CF-, -CF2O-, -OCF2-, -CH2- or a single bond.

[0537] c) preferably the LC medium comprises one or more compounds selected from the group consisting of difluorodibenzochromans of formula BC, chromans of formula CR, and fluorophenanthrene compounds of formulae PH-1 and PH-2,

[0538]

[0539] in

[0540] R B1 ,R B2 ,R CR1 ,R CR2 ,R 1 ,R 2 Each independently has R 2A Meaning. c is 0, 1 or 2. R 1 and R 2 Preferably, independently of one another, they are alkyl or alkoxy radicals having 1 to 6 C atoms.

[0541] The LC media according to the invention preferably comprise the compounds of the formulae BC, CR, PH-1, PH-2 in an amount of 3-20 wt %, in particular in an amount of 3-15 wt %.

[0542] Particularly preferred compounds of formula BC and CR are compounds BC-1 to BC-7 and CR-1 to CR-5,

[0543]

[0544]

[0545]

[0546] in

[0547] alkyl and alkyl * each independently of one another represents a straight-chain alkyl group having 1 to 6 C atoms, and

[0548] alkenyl, and

[0549] alkenyl * each independently of one another represents a straight-chain alkenyl group having 2 to 6 C atoms.

[0550] Very particular preference is given to LC media comprising one, two or three compounds of the formulae BC-2, BF-1 and / or BF-2.

[0551] d) Preferred LC media comprise one or more indane compounds of the formula In,

[0552]

[0553] in

[0554] R 11 ,R 12 ,

[0555] R 13 Each independently of one another represents straight-chain alkyl, alkoxy, alkoxyalkyl or alkenyl having 1 to 6 C atoms.

[0556] R 12 and R 13 Additionally represents halogen, preferably F,

[0557] express

[0558]

[0559] i represents 0, 1 or 2.

[0560] Preferred compounds of formula In are compounds of formula In-1 to In-16 described below:

[0561]

[0562]

[0563] Particularly preferred are compounds of the formulae In-1, In-2, In-3 and In-4.

[0564] The compounds of the formula In and of the subformulae In-1 to In-16 are preferably used in the LC media according to the invention in a concentration of ≥5% by weight, in particular 5 to 30% by weight and very particularly preferably 5 to 25% by weight.

[0565] e) Preferred LC media additionally comprise one or more compounds of the formulae L-1 to L-5,

[0566]

[0567] in

[0568] R and R 1 Each independently has the above R 2A The parameter s represents 1 or 2.

[0569] The compounds of the formulae L-1 to L-5 are preferably used in a concentration of 5 to 50% by weight, in particular 5 to 40% by weight and very particularly preferably 10 to 40% by weight.

[0570] f) Preferred LC media additionally comprise one or more compounds of the formula IIA-Y

[0571]

[0572] Where R 11 and R 12 With the above formula IIA R 2A One of the meanings given, and L 1 and L 2 represents F or Cl identically or differently.

[0573] Preferred compounds of formula IIA-Y are selected from the following sub-formulas

[0574]

[0575]

[0576] Among them, Alkyl and Alkyl * Each independently of one another represents a straight-chain alkyl radical having 1 to 6 C atoms, Alkoxy represents a straight-chain alkoxy radical having 1 to 6 C atoms, Alkenyl and Alkenyl * Each independently of one another represents a straight-chain alkenyl group having 2 to 6 C atoms, and O represents an oxygen atom or a single bond. * Preferably it represents CH2=CH-, CH2=CHCH2CH2-, CH3-CH=CH-, CH3-CH2-CH=CH-, CH3-(CH2)2-CH=CH-, CH3-(CH2)3-CH=CH- or CH3-CH=CH-(CH2)2-.

[0577] Particularly preferred compounds of formula IIA-Y are selected from the following sub-formulae:

[0578]

[0579] Among them, Alkoxy and Alkoxy * has the meaning defined above and preferably represents methoxy, ethoxy, n-propoxy, n-butoxy or n-pentoxy.

[0580] g) LC medium additionally comprising one or more quaternary compounds selected from the group consisting of:

[0581]

[0582] in

[0583] R Q is alkyl, alkoxy, oxaalkyl or alkoxyalkyl having 1 to 9 C atoms or alkenyl or alkenyloxy having 2 to 9 C atoms, all of which are optionally fluorinated,

[0584] X Qis F, Cl, a haloalkyl or alkoxy group having 1 to 6 C atoms, or a haloalkenyl or alkenyloxy group having 2 to 6 C atoms,

[0585] L Q1 -L Q6 Each independently is H or F, wherein L Q1 -L Q6 At least one of them is F.

[0586] Preferred compounds of formula Q are those wherein R Q Those representing straight-chain alkyl radicals having 2 to 6 C atoms, very preferably ethyl, n-propyl or n-butyl.

[0587] Preferred compounds of formula Q are those wherein L Q3 and L Q4 Those wherein L is F. Further preferred compounds of formula Q are those wherein L Q3 , L Q4 and L Q1 and L Q2 Those in which one or two are F.

[0588] Preferred compounds of formula Q are those wherein X Q Those representing F or OCF3, F being very preferred.

[0589] The compound of formula Q is preferably selected from the following sub-formula

[0590]

[0591] Where R Q has one of the meanings of the formula Q or one of the preferred meanings given above or below, and is preferably ethyl, n-propyl or n-butyl.

[0592] Particularly preferred are compounds of formula Q1, especially those wherein R Q Those which are n-propyl.

[0593] Preferably, the proportion of the compound of formula Q in the LC host mixture is >0 to ≤5 wt%, very preferably 0.05-2 wt%, more preferably 0.1-1 wt%, most preferably 0.1-0.8 wt%.

[0594] Preferably the LC medium contains 1 to 5, preferably 1 or 2, compounds of formula Q.

[0595] Adding the quaterphenyl compound of formula Q to the LC host mixture can reduce the ODF inhomogeneity while maintaining high UV absorption, achieve fast and complete polymerization, produce strong and fast tilt, and improve the UV stability of the LC medium.

[0596] Furthermore, adding the compound of formula Q having positive dielectric anisotropy to the LC medium having negative dielectric anisotropy can better control the values ​​of dielectric constants ε|| and ε⊥, and in particular, can achieve a high dielectric constant ε || value and keep the dielectric anisotropy Δε constant, thereby reducing the kickback voltage and reducing image sticking.

[0597] The LC media according to the invention preferably comprise

[0598] - one or more compounds of each of the formulae I1 and I2, preferably each of the formulae I1, I2 and I3, or their subformulae, preferably in a total concentration of 0.01% to 2.0%, more preferably 0.1% to 1.0%, most preferably 0.2% to 0.8%,

[0599] and / or

[0600] - one or more compounds of formula IIA, preferably in a total concentration of 5% to 30%, more preferably 7% to 25%, particularly preferably 10% to 20%;

[0601] and / or

[0602] - one or more compounds of formula IIA and IIB, preferably in a total concentration of 30% to 45%;

[0603] and / or

[0604] - one or more compounds of formula IV, preferably in a total concentration of 35% to 70%, more preferably 40% to 65%, particularly preferably 45% to 60%;

[0605] and / or

[0606] - one or more compounds of formula IV-3, preferably in a total concentration of 35% to 60%, more preferably 40% to 55%, particularly preferably 45% to 50%;

[0607] and / or

[0608] - one or more compounds of formula III-2, preferably formula III-2-6, preferably in a total concentration of 2% to 25%, more preferably 5% to 15%, particularly preferably 5 to 12%.

[0609] In particular, the medium contains

[0610] - one or more compounds CY-n-Om, in particular CY-3-O4, CY-5-O4 and / or CY-3-O2, preferably in a total concentration of 5% to 30%, preferably 10% to 20%;

[0611] and / or

[0612] - one or more compounds PY-n-Om, in particular PY-3-O2 and / or PY-1-O2, preferably in a total concentration of 5% to 30%, preferably 5% to 20%;

[0613] and / or

[0614] - CPY-n-Om, in particular CPY-2-O2, CPY-3-O2 and / or CPY-5-O2, preferably in a total concentration of >5%, in particular 7% to 20%, based on the entire mixture,

[0615] and / or

[0616] - one or more compounds CCY-n-Om, preferably CCY-4-O2, CCY-3-O2, CCY-3-O3, CCY-3-O1 and / or CCY-5-O2, preferably in a total concentration of >3%, in particular 5-15%, based on the entire mixture;

[0617] and / or

[0618] - one or more compounds CPY-n-Om, preferably CPY-2-O2 and / or CPY-3-O2, preferably in a total concentration of >3%, in particular 5-15%, based on the entire mixture;

[0619] and / or

[0620] - CLY-n-Om, preferably CLY-2-O4, CLY-3-O2 and / or CLY-3-O3, preferably in a total concentration of >5%, in particular 10-30%, very preferably 15-20%, based on the entire mixture;

[0621] and / or

[0622] - CPY-n-Om and CY-n-Om, preferably in a total concentration of 10-80%, based on the entire mixture,

[0623] and / or

[0624] - CPY-n-Om and PY-n-Om, preferably CPY-2-O2 and / or CPY-3-O2 and PY-3-O2 or PY-1-O2, preferably in a total concentration of 5-20%, more preferably 10-15%, based on the entire mixture,

[0625] and / or

[0626] -CC-3-V, preferably in a total concentration of 5 to 50%, based on the entire mixture.

[0627] and / or

[0628] - compounds of formula CC-3-V1, in a total concentration of 5-40%, more preferably 15%-35%, particularly preferably 20%-30%,

[0629] and / or

[0630] - one or more compounds of formula B-nO-Om and / or B(S)-nO-Om, in particular compounds B(S)-2O-O4 and / or B(S)-2O-O5, preferably in a concentration of 2-12%.

[0631] and / or

[0632] -0.1%-3% of compound PPGU-3-F,

[0633] and / or

[0634] -Compound B(S)-(c5)1O-O2:

[0635]

[0636] The invention further relates to an electro-optical display with active-matrix addressing, characterized in that it contains a liquid-crystalline medium according to claim 1 as dielectric and in which the display is a VA, SA-VA, IPS, U-IPS, FFS, UB-FFS, SA-FFS, PS-VA, PS-OCB, PS-IPS, PS-FFS, PS-UB-FFS, PS-posi-VA, PS-TN, polymer-stabilized SA-VA or polymer-stabilized SA-FFS display.

[0637] It is advantageous for the liquid-crystalline media according to the invention to have a nematic phase preferably at ≤-20° C. to ≥70° C., particularly preferably at ≤-30° C. to ≥80° C. and very particularly preferably at ≤-40° C. to ≥90° C.

[0638] The media of the present invention have a clearing temperature of 70°C or higher, preferably 74°C or higher.

[0639] The expression "having a nematic phase" here means on the one hand that at low temperatures no smectic phase and no crystallization is observed at the corresponding temperature and on the other hand that the nematic phase does not yet clear on heating. The low-temperature investigations are carried out in a flow viscometer at the corresponding temperature and are checked by storage for at least 100 hours in a test cell with a layer thickness corresponding to the electro-optical use. If the storage stability in a corresponding test cell at a temperature of -20°C is 1000 hours or more, the medium is said to be stable at this temperature. At temperatures of -30°C and -40°C, the corresponding times are 500 hours and 250 hours, respectively. At high temperatures, the clearing point is measured in a capillary by conventional methods.

[0640] The liquid crystal mixture preferably has a nematic phase range of at least 60 K and a maximum of 30 mm at 20° C. 2 ·s -1 The flow viscosity ν 20 .

[0641] The mixture is nematic at a temperature of -20°C or below, preferably at -30°C or below, very preferably at -40°C or below.

[0642] The value of the birefringence Δn in the liquid-crystal mixture is generally from 0.07 to 0.16, preferably from 0.08 to 0.15 and very preferably from 0.09 to 0.14.

[0643] In a preferred embodiment of the invention, the birefringence of the medium is 0.090-0.110, preferably 0.095-0.105, in particular 0.100-0.105.

[0644] In another preferred embodiment, the medium of the present invention has a birefringence of 0.120 or more, preferably 0.125-0.145, more preferably 0.130-0.140.

[0645] The liquid crystal mixtures according to the invention have a dielectric anisotropy Δε of -1.5 to -8.0, preferably -2.0 to -4.0, in particular -2.5 to -3.5,

[0646] The rotational viscosity γ1 at 20° C. is preferably ≤120 mPa·s, in particular ≤100 mPa·s.

[0647] In a preferred embodiment, the rotational viscosity γ1 at 20° C. is ≤100 mPa·s, in particular ≤95 mPa·s.

[0648] The liquid-crystal media according to the invention have relatively low threshold voltages (V0). They are preferably from 1.7 V to 3.0 V, particularly preferably ≤2.7 V and very particularly preferably ≤2.5 V.

[0649] For the present invention, unless explicitly stated otherwise, the term "threshold voltage" relates to the capacitive threshold (V0), also called Freedericks threshold.

[0650] Furthermore, the liquid-crystal media according to the invention have high voltage holding ratio values ​​in liquid-crystal cells.

[0651] Typically, LC media having a low addressing voltage or threshold voltage show lower voltage holding ratios than those LC media having a higher addressing voltage or threshold voltage, and vice versa.

[0652] For the purposes of the present invention, the term "dielectrically positive compounds" refers to compounds with Δε>1.5, the term "dielectrically neutral compounds" refers to those with -1.5≤Δε≤1.5 and the term "dielectrically negative compounds" refers to those with Δε<-1.5. The dielectric anisotropy of the compounds is determined here by dissolving 10% of the compound in a liquid-crystal host in at least one test cell, the test cell having in each case a layer thickness of 20 μm and having a homeotropic and planar surface alignment at 1 kHz. The measuring voltage is generally between 0.5 V and 1.0 V, but is always below the capacitance threshold of the respective liquid-crystal mixture under investigation.

[0653] All temperature values ​​described in the present invention are in ° C.

[0654] The LC media according to the invention are suitable for all VA-TFT (vertically aligned thin film transistor) applications, such as VAN (vertically aligned nematic), MVA (multidomain VA), (S)-PVA (super patterned VA), ASV (advanced super view or axisymmetric VA), PSA (polymer stabilized VA) and PS-VA (polymer stabilized VA). In addition, they are suitable for IPS (in-plane switching) and FFS (fringe field switching) applications with negative Δε.

[0655] The nematic LC media in the displays according to the invention generally comprise two components A and B, which themselves consist of one or more individual compounds.

[0656] Component A has a pronounced negative dielectric anisotropy and provides a dielectric anisotropy of ≤-0.5 for the nematic phase. In addition to one or more compounds of the formula I, it preferably comprises compounds of the formulae IIA, IIB and / or IIC, and one or more compounds of the formula IV-1.

[0657] The proportion of component A is preferably 45-100%, in particular 60-85%.

[0658] For component A, preference is given to selecting one or more individual compounds with a Δε value of ≤−0.8. The smaller the proportion of A in the overall mixture, the more negative this value will necessarily be.

[0659] Component B has obvious nematogeneity and its flow viscosity at 20°C is not more than 30 mm 2 ·s -1 , preferably no more than 25mm 2 ·s -1 .

[0660] A variety of suitable materials are known to the skilled person from the literature. Compounds of formula O-17 are particularly preferred.

[0661] Particularly preferred individual compounds in component B are extremely low viscosity nematic liquid crystals, the flow viscosity of which at 20° C. is not greater than 18 mm 2 ·s -1 , preferably no more than 12mm 2 ·s -1 .

[0662] Component B is monotropically or enantiotropically nematic, has no smectic phase, and is capable of preventing the occurrence of a smectic phase in the LC medium at very low temperatures. For example, if various highly nematic materials are added to a smectic liquid crystal mixture, the nematicity of these materials can be contrasted by suppressing the extent to which the smectic phase is reached.

[0663] The mixture may also optionally comprise a component C comprising compounds having a dielectric anisotropy of Δε≥1.5. These so-called positive compounds are generally present in mixtures of negative dielectric anisotropy in an amount of ≤20% by weight, based on the entire mixture.

[0664] In addition to one or more compounds of the formulae I1, I2 and optionally I3, the medium preferably comprises 4 to 15, in particular 5 to 12 and particularly preferably <10 compounds of the formulae IIA, IIB and / or IIC and optionally one or more compounds of the formula IV-1.

[0665] Besides the compounds of the formulae I1, I2 and optionally I3 and the compounds of the formulae IIA, IIB and / or IIC and optionally IV-1, further constituents may also be present in an amount of up to 45%, but preferably up to 35%, in particular up to 10%, of the total mixture.

[0666] The further components are preferably selected from nematic or nematogenic substances, in particular from the known substances of the class of azobenzene, benzylidene aniline, biphenyl, terphenyl, phenyl or cyclohexyl benzoate, phenyl or cyclohexyl cyclohexanecarboxylate, phenylcyclohexane, cyclohexylbiphenyl, cyclohexylcyclohexane, cyclohexylnaphthalene, 1,4-dicyclohexylbiphenyl or cyclohexylpyrimidine, phenyldioxane or cyclohexyldioxane, optionally halogenated stilbenes, benzylphenyl ethers, tolans and substituted cinnamic esters.

[0667] The most important compounds suitable as constituents of this type of liquid-crystalline phase can be characterized by the following formula IV

[0668] R 20 -LGER 21 IV

[0669] wherein L and E each designate a carbocyclic or heterocyclic system from the group formed by 1,4-disubstituted benzene and cyclohexane rings, 4,4′-disubstituted biphenyl, phenylcyclohexane and cyclohexylcyclohexane systems, 2,5-disubstituted pyrimidine and 1,3-dioxane rings, 2,6-disubstituted naphthalene, dihydronaphthalene and tetrahydronaphthalene, quinazoline and tetrahydroquinazoline,

[0670] G represents -CH=CH- -N(O)=N-

[0671] -CH=CQ- -CH=N(O)-

[0672] -C≡C- -CH2-CH2-

[0673] -CO-O- -CH2-O-

[0674] -CO-S- -CH2-S-

[0675] -CH=N- -COO-Phe-COO-

[0676] -CF2O- -CF=CF-

[0677] -OCF2- -OCH2-

[0678] -(CH2)4- -(CH2)3O-

[0679] or a CC single bond, Q represents halogen, preferably chlorine or -CN, and R 20 and R 21 Each designates an alkyl, alkenyl, alkoxy, alkoxyalkyl or alkoxycarbonyloxy group having up to 18, preferably up to 8, carbon atoms, or one of these groups designates CN, NC, NO2, NCS, CF3, SF5, OCF3, F, Cl or Br.

[0680] In most of these compounds, R 20 and R 21 Different from each other, one of these groups is usually an alkyl or alkoxy group. Other variations of the proposed substituents are also common. Many such substances or mixtures thereof are also commercially available. All these substances can be prepared by methods known from the literature.

[0681] It goes without saying for the person skilled in the art that the VA, IPS or FFS mixtures according to the invention may also comprise compounds in which, for example, H, N, O, Cl and F are replaced by corresponding isotopes.

[0682] The combination of the compounds of the preferred embodiments mentioned above with the above-mentioned polymeric compounds leads to low threshold voltages, low rotational viscosities and very good low-temperature stability in the LC media according to the invention, while maintaining high bright spots and high HR values, and allows particularly low tilt angles (i.e. large tilts) to be established quickly in PSA displays. In particular, the LC media exhibit significantly shortened response times, in particular gray-to-gray response times, in PSA displays compared to LC media from the prior art.

[0683] The LC media according to the invention may also contain further additives known to the person skilled in the art and described in the literature, for example polymerization initiators, inhibitors, stabilizers, surface-active substances or chiral dopants. These may be polymerizable or non-polymerizable. Polymerizable additives are respectively assigned to the polymerizable component or component A). Non-polymerizable additives are respectively assigned to the non-polymerizable component or component B).

[0684] Furthermore, it is possible to add, for example, 0 to 15% by weight of pleochroic dyes to the LC medium, in addition to nanoparticles, conductive salts, preferably ethyldimethyldodecyl 4-hexyloxyammonium benzoate, tetrabutylammonium tetraphenylborate or complex salts of crown ethers (see, for example, Haller et al., Mol. Cryst. Liq. Cryst. 24 , 249-258 (1973)) for improving the electrical conductivity, or adding substances for modifying the dielectric anisotropy, viscosity and / or orientation of the nematic phase. For example, DE-A 22 09 127, 2240 864, 23 21 632, 23 38 281, 24 50 088, 26 37 430 and 28 53 728 describe substances of this type.

[0685] The individual components of the preferred embodiments of the LC media according to the invention listed above are known or the processes for preparing them are available from the prior art to the person skilled in the relevant art, since they are based on standard processes described in the literature. The corresponding compounds of the formula CY are described, for example, in EP-A-0 364 538. The corresponding compounds of the formula ZK are described, for example, in DE-A-26 36 684 and DE-A-33 21 373.

[0686] The LC media which can be used according to the invention are prepared in a manner conventional per se, for example by mixing one or more of the above-mentioned compounds with one or more polymerizable compounds as defined above, and optionally with further liquid-crystalline compounds and / or additives. Usually, the desired amount of the components used in smaller amounts is dissolved in the components making up the main constituents, this being advantageously done at elevated temperature. It is also possible to mix the solutions of the components in an organic solvent, for example acetone, chloroform or methanol, and to remove the solvent again, for example by distillation after thorough mixing. The invention also relates to a process for the preparation of the LC media according to the invention.

[0687] It goes without saying to the person skilled in the art that the LC media according to the invention can also comprise compounds in which H, N, O, Cl, F are replaced by corresponding isotopes, for example deuterium.

[0688] The following examples illustrate the present invention but do not limit the present invention. However, they show preferred mixture concepts to those skilled in the art, as well as the compounds preferably used and their respective concentrations, and their combinations with each other. In addition, the examples illustrate which properties and combinations of properties are obtainable.

[0689] Preferred mixture compositions are shown in Table A below.

[0690] Table A

[0691] In Table A, m and n are independently an integer of 1 to 12, preferably 1, 2, 3, 4, 5 or 6, k is 0, 1, 2, 3, 4, 5 or 6, and (O)C m H 2m+1 Represents C m H 2m+1 or OC m H 2m+1 .

[0692]

[0693]

[0694]

[0695]

[0696]

[0697]

[0698]

[0699]

[0700]

[0701]

[0702]

[0703]

[0704]

[0705]

[0706]

[0707]

[0708]

[0709]

[0710]

[0711]

[0712]

[0713] In a first preferred embodiment of the invention, the inventive LC media, in particular those having positive dielectric anisotropy, comprise one or more compounds selected from the compounds of Table A1.

[0714] In a second preferred embodiment of the invention, the inventive LC media, in particular those having a negative dielectric anisotropy, comprise one or more compounds selected from the compounds of Table A2.

[0715] Table B

[0716] Table B shows chiral dopants that can be added to the LC media of the present invention.

[0717]

[0718]

[0719] The LC medium preferably comprises 0 to 10 wt %, in particular 0.01 to 5 wt %, particularly preferably 0.1 to 3 wt % of dopant. The LC medium preferably comprises one or more dopants selected from the compounds of Table B.

[0720] Table C

[0721] Table C shows possible stabilizers which can be added to the LC media according to the invention. Here n represents an integer from 1 to 12, preferably 1, 2, 3, 4, 5, 6, 7 or 8, and the terminal methyl groups are not shown.

[0722]

[0723]

[0724]

[0725]

[0726]

[0727]

[0728] The LC medium preferably comprises 0 to 10 wt %, in particular 1 ppm to 5 wt %, particularly preferably 1 ppm to 1 wt % of stabilizer. The LC medium preferably comprises one or more stabilizers selected from the compounds of Table C.

[0729] Table D

[0730] Table D shows exemplary reactive mesogenic compounds that can be used in the LC media of the present invention.

[0731]

[0732]

[0733]

[0734]

[0735]

[0736]

[0737]

[0738]

[0739]

[0740]

[0741]

[0742]

[0743]

[0744]

[0745]

[0746]

[0747]

[0748]

[0749]

[0750]

[0751] In a preferred embodiment, the mixture of the present invention comprises one or more polymerizable compounds, preferably selected from the polymerizable compounds of formula RM-1 to RM-144. Among these, compounds RM-1, RM-4, RM-8, RM-17, RM-19, RM-35, RM-37, RM-39, RM-40, RM-41, RM-48, RM-52, RM-54, RM-57, RM-64, RM-74, RM-76, RM-88, RM-102, RM-103, RM-109, RM-117, RM-120, RM-121, RM-122 and RM-145 to RM-152 are particularly preferred.

[0752] In another preferred embodiment, the mixtures according to the invention comprise one or more polymerizable compounds selected from the group consisting of formulae RM-145 to RM-152, very preferably from the group consisting of formulae RM-147 to RM-152.

[0753] Table E

[0754] Table E shows self-aligning additives for homeotropic alignment which can be used together with the polymerisable compounds of the formula I in the LC media of SA-VA and SA-FFS displays according to the invention:

[0755]

[0756]

[0757]

[0758]

[0759]

[0760]

[0761]

[0762]

[0763]

[0764]

[0765]

[0766] In a preferred embodiment, the LC media of SA-VA and SA-FFS displays according to the invention comprise one or more SA additives selected from the group consisting of formulae SA-1 to SA-48, preferably selected from the group consisting of formulae SA-14 to SA-48, very preferably formulae SA-20 to SA-34 and SA-44, and one or more RMs of formula I. Example

[0767] The following examples explain the present invention without limiting it. However, they show preferred mixture concepts and preferably used compounds and their corresponding concentrations and their combinations with each other to those skilled in the art. In addition, the examples illustrate obtainable properties and property combinations.

[0768] In addition, the following abbreviations and symbols are used:

[0769] V0 represents the threshold voltage at 20°C, capacitive [V],

[0770] n e represents the extraordinary refractive index at 20°C and 589nm,

[0771] n o represents the ordinary refractive index at 20°C and 589nm,

[0772] Δn represents the optical anisotropy at 20°C and 589 nm,

[0773] ε ⊥ represents the dielectric constant perpendicular to the director at 20°C and 1kHz,

[0774] ε || represents the dielectric constant parallel to the director at 20°C and 1kHz,

[0775] Δε represents the dielectric anisotropy at 20°C and 1kHz,

[0776] cl.p., T(N,I) represents the clearing point [℃],

[0777] γ1 represents the rotational viscosity at 20°C [mPa·s],

[0778] K1 is the elastic constant at 20°C, “slope” deformation [pN],

[0779] K2 represents the elastic constant at 20°C, "torsion" deformation [pN],

[0780] K3 represents the elastic constant at 20°C, "bending" deformation [pN].

[0781] Unless expressly stated otherwise, all concentrations in the present application are given as percentages by weight and relate to the respective entire mixture, which comprises all solid or liquid-crystalline components (without solvent).

[0782] Unless otherwise stated, all temperature values ​​indicated in this application, such as melting point T(C,N), transition from smectic phase (S) to nematic phase (N) T(S,N) and clearing point T(N,I) are expressed in degrees Celsius (°C). Mp stands for 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 transition temperatures.

[0783] 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 are valid for a temperature of 20°C, with Δn measured at 589 nm and Δε measured at 1 kHz, unless expressly stated otherwise in each case.

[0784] The term "threshold voltage" as used in the present invention relates to the capacitive threshold (V0), which is also referred to as the Freedericks threshold unless otherwise stated. In the embodiments, the optical threshold is also generally for a relative contrast ratio of 10% (V 10 ) given.

[0785] Unless otherwise stated, the process for polymerising the polymerisable compounds in a PSA display as described above and below is carried out at a temperature at which the LC medium exhibits a liquid crystal phase, preferably a nematic phase, and most preferably at room temperature.

[0786] Unless otherwise stated, the methods for preparing the test cells and measuring their electro-optical and other properties were performed by the methods described below or methods analogous thereto.

[0787] The display used to measure the capacitive threshold voltage consisted of two plane-parallel glass outer plates separated by 25 μm, each with an electrode layer on the inside and an unrubbed polyimide alignment layer on top, which resulted in vertical edge alignment of the liquid crystal molecules.

[0788] The PSVA display or PSVA test box used to measure the tilt angle consists of two plane-parallel glass outer plates separated by 4 μm, each of which has an electrode layer on the inner side and a polyimide alignment layer on top, unless otherwise specified, wherein the two polyimide layers are rubbed antiparallel to each other and cause homeotropic edge alignment of the liquid crystal molecules. The SAVA display or test box has the same structure, but one or both of the polyimide layers are omitted.

[0789] The polymerizable compound is polymerized in the display or test box by irradiating with UV light of defined intensity for a predetermined time while applying voltage (usually 10V-30V AC, 1kHz) to the display. In the examples, unless otherwise stated, a metal halide lamp and 100mW / cm 2 The intensity was measured using a standard instrument (Hoenle UV-meter high end with UV sensor).

[0790] The tilt angle was determined using the Mueller Matrix Polarimeter "AxoScan" from Axometrics. Small values ​​(ie large deviations from an angle of 90°) correspond here to large tilts.

[0791] Unless otherwise stated, the term "tilt angle" means the angle between the LC director and the substrate, and "LC director" means the preferred orientation direction of the optical principal axes of the LC molecules in a LC molecule layer having uniform orientation, which in the case of rod-shaped, uniaxially positively birefringent LC molecules corresponds to their molecular long axes.

[0792] Example 1

[0793] The nematic LC host mixture N1 was prepared as follows

[0794]

[0795] Polymerizable mixture

[0796] A polymerizable mixture is prepared by adding one or more polymerizable compounds M1, M2 and M3 and a stabilizer S1 to a nematic LC host mixture N1.

[0797]

[0798] The composition of the polymerizable mixture is shown in Table 1.

[0799] Table 1 - Composition of polymerizable mixtures

[0800] Concentration (wt.%) P1 P2 P3 P4 P5 N1(Main body) 99.685 99.635 99.585 99.485 99.485 S1(stabilizer) 0.015 0.015 0.015 0.015 0.015 M2 0.300 0.350 0.400 0.300 0.350 M2 - - - 0.200 0.100 M3 - - - - 0.050

[0801] Tilt Angle Generation

[0802] Each of the polymerizable mixtures P1 to P5 was filled into a PSVA test cell having a polymer cell thickness of 3.5 μm.

[0803] To polymerize the polymerizable compounds, the test cell was exposed to UV light using a 365 nm UV-LED lamp from Hoenle in a two-step process. In the UV1 step, a voltage (20 V pp Square wave, 60Hz). In the UV2 step, no voltage was applied. Other conditions were as follows:

[0804] UV1: 10mW / cm 2 , 40°C, 400s

[0805] UV2: 10mW / cm 2 , at room temperature, 160min

[0806] After 12 hours, the resulting tilt angle was measured using a Mueller Matrix Polarimeter "AxoScan" from Axometrics.

[0807] The results are shown in Table 2.

[0808] Table 2 - Tilt Generation

[0809] mixture 90°-Tilt P1 2.1° P2 1.9° P3 3.4° P4 2.8° P5 3.4°

[0810] As can be seen from Table 2, polymerizable mixtures P1 to P5 produce good tilt angles.

[0811] Tilt stability

[0812] Tilt stability, i.e. the change in tilt angle after repeated electrical stressing, is a criterion for assessing the risk of image sticking. Low values ​​of the change in tilt angle indicate high tilt stability and low potential risk of image sticking.

[0813] To determine the tilt stability, the test cell after polymerization as described above was subjected to a 60 V load at 200 Hz. PP Electrical stress was applied with a square wave of 100° for 72 hours. After a relaxation time of 10-20 minutes, the tilt angle was measured again as described above.

[0814] According to equation (1), the change in tilt angle is determined as follows:

[0815] tilt 应力后 -tilt 产生倾斜后 =Δ tilt (1)

[0816] And is shown in the following Table 3.

[0817] The lower the value of Δtilt, the higher the tilt stability.

[0818] Table 3 – Tilt stability

[0819] mixture ΔTilt / ° P1 0.98 P2 0.67 P3 0.78 P4 0.34 P5 0.37

[0820] As can be seen from Table 3, the polymerizable mixtures P1 to P5 show good tilt stability.

[0821] Example 2

[0822] The nematic LC host mixture N2 was prepared as follows

[0823]

[0824] A polymerizable mixture P6 was prepared by adding 0.3% of a polymerizable compound M1 and 0.015% of a stabilizer S1 to a nematic LC host mixture N2.

[0825] Example 3

[0826] The nematic LC host mixture N3 was prepared as follows

[0827]

[0828] A polymerizable mixture P7 was prepared by adding 0.3% of a polymerizable compound M1 and 0.015% of a stabilizer S1 to a nematic LC host mixture N3.

[0829] Example 4

[0830] The nematic LC host mixture N4 was prepared as follows

[0831]

[0832] A polymerizable mixture P8 was prepared by adding 0.3% of a polymerizable compound M1, 0.2% of a polymerizable compound M3 and 0.015% of a stabilizer S1 to a nematic LC host mixture N4.

[0833] Example 5

[0834] The nematic LC host mixture N5 was prepared as follows

[0835]

[0836] Polymerizable mixture

[0837] Polymerizable mixtures P9 to P11 are prepared by adding one or more polymerizable compounds M1, M2 and M3 and SA additive SA32 to the nematic LC host mixture N5.

[0838]

[0839] The composition of the polymerizable mixture is shown in Table 4.

[0840] Table 4 - Composition of polymerizable mixtures

[0841]

[0842]

[0843] Each polymerizable mixture was filled into a SA-VA test cell having a polymer cell thickness of 4.0 μm.

[0844] To polymerize the polymerizable compounds, the test cell was exposed to UV light in one step (UV1) using a 365 nm UV-LED lamp from Hoenle while applying a voltage (20 V pp Square wave, 60Hz). Other conditions are as follows:

[0845] UV1: 10mW / cm 2 , 40°C, 400s

[0846] UV2: 10mW / cm 2 , at room temperature, 160min

[0847] The tilt angle produced after the UV1 step was measured as described in Example 5. The results are shown in Table 5.

[0848] Table 5 - SA-VA tilt generation (UV1)

[0849] mixture 90°-Tilt P9 2.9° P10 2.3° P11 2.2°

[0850] As can be seen from Table 5, the use of polymerizable mixtures P9 to P11 containing compound M1 of formula I1 resulted in good tilt angles.

[0851] Voltage Holding Ratio (VHR)

[0852] To polymerize the polymerizable compounds, the test cells were exposed to UV light in a two-step process using a 365 nm UV-LED lamp from Hoenle. In the UV1 step, a voltage (20 V pp Square wave, 60Hz). In the UV2 step, no voltage was applied. Other conditions were as follows:

[0853] UV1(LED light): 10mW / cm 2, 40°C, 400s

[0854] UV2 (LED light): 10mW / cm 2 , at room temperature, 160min

[0855] For comparison purposes, other test cells with the mixture were irradiated using a conventional lamp to polymerize the compound in two steps as described above. The conditions were as follows.

[0856] UV1 (Fe-I lamp): 0.53mW / cm 2 , 40℃, 100s

[0857] UV2 (C-type fluorescent lamp): 0.28mW / cm 2 , at room temperature, 100min

[0858] The VHR of the polymerizable LC media was measured at 60°C with an applied voltage of 1 V / 0.6 Hz before and after UV exposure. Photostress generally leads to a decrease in the VHR in LC blends, so the smaller the absolute decrease in the VHR value after stress, the better the performance for display applications.

[0859] The results are shown in Table 6.

[0860] Table 6 - VHR

[0861]

[0862] As can be seen from Table 6, when UV-LED lamps are used for polymerization, the VHR values ​​of the polymerizable mixtures P9, P10 and P11 according to the present invention are significantly higher and reach a sufficient level for display manufacturing. In contrast, when conventional lamps are used, the VHR values ​​are so low that the mixtures are not suitable for SAVA display manufacturing processes.

Claims

1. An LC medium having negative dielectric anisotropy, comprising one or more polymerizable compounds of formula I which show absorption in the range from 340 to 400 nm, selected from trireactive triphenyl compounds of formulae I1-1 to I1-3, where the radicals are independent of one another and have the following meanings on each occurrence, identically or differently: P is an acrylate group or a methacrylate group, Sp is a spacer optionally substituted by a group P, or a single bond, L is F, Cl, Br, -CN or a straight-chain, branched or cyclic alkyl radical having 1 to 25 C atoms, wherein one or more non-adjacent CH2 groups are optionally replaced by -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O-, -N(R) in such a way that the O- and / or S-atoms are not directly connected to each other. 0 )-、-Si(R 0 R 00 )-, -CH=CH- or -C≡C-, and wherein one or more H atoms are each optionally replaced by F or Cl, r1, r2 are 0, 1, 2, 3 or 4, r3 is 0, 1, 2 or 3; and The LC medium further comprises at least one compound of formula I2, selected from the trireactive compounds of formula I2-1 to formula I2-3 Biphenyl compounds: where the radicals are independent of one another and have the following meanings on each occurrence, identically or differently: P is an acrylate group or a methacrylate group, Sp is a spacer optionally substituted by a group P, or a single bond, L is F, Cl, Br, -CN or a straight-chain, branched or cyclic alkyl radical having 1 to 25 C atoms, wherein one or more non-adjacent CH2 groups are optionally replaced by -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O-, -N(R) in such a way that the O- and / or S-atoms are not directly connected to each other. 0 )-、-Si(R 0 R 00 )-, -CH=CH- or -C≡C-, and wherein one or more H atoms are each optionally replaced by F or Cl, r1, r2 are 0, 1, 2, 3 or 4, r3 is 0, 1, 2 or 3; and further comprising one or more compounds of formula II where the radicals are independent of one another and have the following meanings on each occurrence, identically or differently: R 1 and R 2 is a straight-chain, branched or cyclic alkyl radical having 1 to 25 C atoms, wherein one or more non-adjacent CH2 groups are optionally replaced by -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O-, CR- 0 =CR 00 -、-C≡C-、 and wherein one or more H atoms are each optionally replaced by F or Cl, R 0 and R 00 is H or an alkyl radical having 1 to 12 C atoms, A 1 and A 2 is a group selected from the following formula where the radicals are independent of one another and have the following meanings on each occurrence, identically or differently: Z 1 and Z 2 is -CH2CH2-, -CH=CH-, -CF2O-, -OCF2-, -CH2O-, -OCH2-, -CO-O-, -O-CO-, -C2F4-, -CF=CF-, -CH=CH-CH2O- or a single bond, L 1 ,L 2 ,L 3 and L 4 is F, Cl, OCF3, CF3, CH3, CH2F or CHF2, Y is H, F, Cl, CF3, CHF2 or CH3, L C is CH3 or OCH3, a1 is 1 or 2, a2 is 0 or 1.

2. The compound according to claim 1, characterized in that The compound of formula I1 is selected from the following sub-formulas Therein, P and L have one of the meanings given in claim 1 , and Sp′ has one of the meanings given for Sp which is different from a single bond.

3. LC medium according to claim 1, characterized in that The compound of formula I2 is selected from the following sub-formulas Therein, P and L have one of the meanings given in claim 1 , and Sp′ has one of the meanings given for Sp which is different from a single bond.

4. LC medium according to claim 1, characterized in that In addition to the polymerizable compound having absorption in the range of 340 to 400 nm, it also contains one or more polymerizable compounds having two polymerizable groups selected from the group consisting of formula I3 Here, P, Sp, L, r1 and r2 independently of one another have one of the meanings given in claim 1.

5. LC medium according to claim 4, characterized in that The compound of formula I3 is selected from the following sub-formulas Therein, P, Sp, L, r1 and r2 independently of one another have one of the meanings given in claim 1 , and Sp′ has one of the meanings given for Sp which is different from a single bond.

6. LC medium according to claim 4, characterized in that At least one of r1 and r2 is not zero.

7. LC medium according to claim 4, characterized in that The compound of formula I3 is selected from the following sub-formulas Here, P, Sp' and L have one of the meanings given in claim 1.

8. LC medium according to claim 1, characterized in that It comprises one or more compounds of formula II selected from compounds of formula IIA, IIB, IIC and IID in, R 2A and R 2B each independently of one another represents H, alkyl or alkenyl with up to 15 C atoms, which is unsubstituted, monosubstituted by CN or CF3 or at least monosubstituted by halogen, wherein in addition one or more CH2 groups in these radicals can be replaced by -O-, -S ... -C≡C-, -CF2O-, -OCF2-, -OC-O- or -O-CO-, L 1 -L 4 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-, -CH=CH-, -CF2O-, -OCF2-, -CH2O-, -OCH2-, -COO-, -OCO-, -C2F4-, -CF=CF-, -CH=CHCH2O-, p represents 0, 1, or 2, and Each time q appears, it represents 0 or 1, either identically or differently.

9. LC medium according to claim 1, characterized in that It also comprises one or more compounds of formula III in R 11 and R 12 each independently of one another represents H, alkyl or alkoxy having 1 to 15 C atoms, wherein one or more CH2 groups in these groups can each independently of one another be separated in such a way that the O atoms are not directly connected to one another -C≡C-, -CF2O-, -OCF2-, -CH=CH-, replaced by -O-, -CO-O- or -O-CO-, and wherein in addition, one or more H atoms may be replaced by halogen, A 3 Each occurrence represents independently of each other a) 1,4-cyclohexenyl or 1,4-cyclohexylene, in which one or two non-adjacent CH2 groups may be replaced by -O- or -S-, b) 1,4-phenylene, in which one or both CH groups may be replaced by N, or c) a radical selected from the group consisting of spiro[3.3]heptane-2,6-diyl, 1,4-bicyclo[2.2.2]octane-2,6-diyl, naphthalene-2,6-diyl, decahydronaphthalene-2,6-diyl, 1,2,3,4-tetrahydronaphthalene-2,6-diyl, phenanthrene-2,7-diyl and fluorene-2,7-diyl, wherein the groups a), b) and c) may be mono- or poly-substituted by halogen atoms, n represents 0, 1 or 2, Z 1 Each occurrence independently represents -CO-O-, -O-CO-, -CF2O-, -OCF2-, -CH2O-, -OCH2-, -CH2-, -CH2CH2-, -(CH2)4-, -CH=CH-CH2O-, -C2F4-, -CH2CF2-, -CF2CH2-, -CF=CF-, -CH=CF-, -CF=CH-, -CH=CH-, -C≡C- or a single bond, L 11 and L 12 each independently represents F, Cl, CF3 or CHF2, and W represents O or S.

10. LC medium according to claim 1, characterized in that It also comprises 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 It represents an unsubstituted alkyl group having 1 to 7 C atoms or an unsubstituted alkoxy group having 1 to 6 C atoms, or an unsubstituted alkenyl group having 2 to 7 C atoms.

11. LC medium according to claim 1, characterized in that It also comprises one or more compounds of formula V in R 51 and R 52 Independently of each other, they have 41 and R 42 One of the meanings given, Same or different Z 51 ,Z 52 each independently represents -CH2-CH2-, -CH2-O-, -CH=CH-, -C≡C-, -COO- or a single bond, and n is 1 or 2.

12. LC medium according to claim 1, characterized in that It also comprises one or more additives selected from stabilizers, chiral dopants, polymerization initiators and self-aligning additives.

13. Process for preparing an LC medium according to any of claims 1 to 12, comprising the steps of mixing one or more polymerisable compounds as defined in any of claims 1 to 7 with one or more compounds of the formula II, III, IV and / or V as defined in any of claims 1 or 8 to 12, and optionally with other liquid-crystalline compounds and / or additives, and optionally polymerising the polymerisable compounds.

14. LC display comprising an LC medium as defined in any of claims 1 to 13.

15. The LC display according to claim 14, which is a PSA or SA display.

16. LC display according to claim 14, which is a PS-VA, PS-IPS, PS-FFS or SA-VA display.

17. An LC display according to claim 14 or 15, characterised in that It comprises two substrates, at least one of which is transparent to light, an electrode arranged on each substrate, or two electrodes arranged on only one substrate, and a layer of an LC medium according to any of claims 1 to 11 located between the substrates, wherein the polymerizable compound is polymerized between the substrates of the display by UV light polymerization.

18. A method of manufacturing an LC display according to claim 17, comprising the steps of providing an LC medium according to any one of claims 1 to 16 between substrates of a display, and polymerizing the polymerizable compound by irradiation with UV light while applying a voltage to electrodes of the display.

19. The method according to claim 18, characterized in that The wavelength of the UV light is in the range of 350 to <370 nm.

20. The method according to claim 18, characterized in that The wavelength of the UV light is in the range of 355-368 nm.

21. The method according to claim 18 or 19, characterized in that Irradiation with UV light was performed using a UV-LED lamp.

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