Polymerizable compounds and their use in liquid crystal displays

Abstract

The present application relates to polymerisable compounds, to processes and intermediates for preparing the same, to liquid crystal (LC) media comprising the same, and to the use of the polymerisable compounds and LC media for optical, optoelectronic and electronic purposes, in particular in LC displays, especially in LC displays of the polymer sustained alignment (PS, PSA) and self-alignment (SA) type.

Description

[0001] The present application relates to polymerisable compounds, to processes and intermediates for preparing the same, to liquid crystal (LC) media comprising the same, and to the use of the polymerisable compounds and LC media for optical, optoelectronic and electronic purposes, in particular in LC displays, especially in LC displays of the polymer sustained alignment (PS, PSA) and self- alignment (SA) type.

[0002] One mode of liquid crystal display (LCD) currently in use is the TN ("twisted nematic") mode. However, TN LCDs have the disadvantage that the contrast has a strong dependence on the viewing angle.

[0003] In addition, so-called VA (vertically aligned) displays with a wider viewing angle are known. The LC cell of a VA display contains a layer of LC medium between two transparent electrodes, where the LC medium usually has a negative dielectric anisotropy. In the unpowered state, the molecules of the LC layer are aligned perpendicularly to the electrode surfaces (homeotropically) or have a tilted homeotropic alignment. When a voltage is applied to the two electrodes, a re-alignment of the LC molecules parallel to the electrode surfaces takes place.

[0004] In addition, OCB ("optically compensated birefringence") displays are known, which are based on the birefringence effect and have an LC layer with a so-called "bend" alignment and usually a positive dielectric anisotropy. Upon application of a voltage, a re-alignment of the LC molecules perpendicular to the electrode surfaces takes place. In addition, OCB displays usually contain one or more birefringent optical retardation films to prevent an undesired light transmission of the bend cell in the dark state. OCB displays have a wider viewing angle and a shorter response time than TN displays.

[0005] Also known are so-called IPS ("in-plane switching") displays, which contain an LC layer between two substrates, where both electrodes are only arranged on one of the two substrates and have a comb structure which engages with one another. Upon application of a voltage to the electrodes, an electric field is thus generated between them which has a significant component parallel to the LC layer. This leads to a re-alignment of the LC molecules in the layer plane.

[0006] In addition, so-called FFS (fringe field switching) displays have been reported (see, inter alia, S. H. Jung et al., Jpn. J. Appl. Phys., Vol. 43, No. 3, 2004, 1028) which contain two electrodes on the same substrate, one of which is structured in a comb-like fashion and the other is unstructured. Thereby a strong so-called "fringe field" is generated, i.e. a strong electric field close to the edges of the electrodes, and such electric fields in the whole cell which have both a strong vertical component as well as a strong horizontal component. FFS displays have a small contrast viewing angle dependence. FFS displays usually contain an LC medium having a positive dielectric anisotropy, and an alignment layer, usually a polyimide alignment layer, which provides a planar alignment of the molecules of the LC medium.

[0007] FFS displays can be operated as active matrix or passive matrix displays. In the case of active matrix displays, the individual pixels are usually addressed by means of integrated non-linear active elements such as transistors (e.g. thin-film transistors or "TFTs"), whereas in the case of passive matrix displays, the individual pixels are usually addressed according to multiplexing methods as known in the art.

[0008] Furthermore, FFS displays have been disclosed (cf. S. H. Lee et al., Appl. Phys. Lett. 73 (20), 1998, 2882-2883 and S. H. Lee et al., Liquid Crystals 39 (9), 2012, 1141-1148) which have a similar electrode design and layer thickness as FFS displays, but comprise a layer of an LC medium having a negative dielectric anisotropy instead of a layer of an LC medium having a positive dielectric anisotropy. In comparison to LC media having a positive dielectric anisotropy, LC media having a negative dielectric anisotropy show a more advantageous director orientation with less tilt and more twist of the orientation, which results in these displays having a higher transmission. The displays also comprise an alignment layer, preferably a polyimide provided on at least one of the substrates, which is in contact with the LC medium and induces a planar alignment of the LC molecules of the LC medium. These displays are also referred to as "ultra-brightness FFS (UB-FFS)" mode displays. These displays require LC media having a high reliability.

[0009] The term "reliability" as used in the following means the quality of the performance of the display over time and under different stress loads, such as light load, temperature, humidity, voltage, and includes display effects such as image sticking (both area and line image sticking), mura, yogore, etc., which are known to the person skilled in the art of LC displays. As a standard parameter for classifying the reliability, the voltage holding ratio (VHR) value is usually used, which is a measure for maintaining a constant voltage in a test display. Among other factors, a high VHR is a prerequisite for a high reliability of the LC medium.

[0010] In the newer type of VA displays, the uniform alignment of the LC molecules is limited to a plurality of relatively small domains within the LC cell. Between these domains disclinations, also called tilt domains, can exist. VA displays with tilt domains have a greater viewing angle independence of contrast and grey shade than conventional VA displays. In addition, this type of display is easier to produce, since the additional electrode surface treatment (e.g. by rubbing) for aligning the molecules uniformly in the on state is no longer required. Instead, the preferential direction of the tilt or pretilt angle is controlled by a special design of the electrodes.

[0011] In so-called MVA (multi-domain vertical alignment) displays, this is usually achieved by electrodes with protrusions that cause a local pretilt. Thereby, the LC molecules are aligned parallel to the electrode surface in different, defined cell regions in different directions upon application of a voltage. A "controlled" switching is thereby achieved and the formation of disturbing disclination lines is prevented. Although this arrangement improves the viewing angle of the display, it leads to a reduction in its light transmission. A further improvement of MVA uses protrusions on only one electrode side, while the opposite electrode has slits, which improves the light transmission. The slit electrode generates a non-uniform electric field in the LC cell upon application of a voltage, meaning that a controlled switching is still achieved. To further improve the light transmission, the spacing between the slits and the protrusions can be enlarged, but this in turn leads to a lengthening of the response time. In so-called PVA ("patterned VA"), the protrusions are made completely superfluous, since both electrodes are structured by slits on the opposite side, which leads to an increased contrast and an improved light transmission, but this is technically difficult and makes the display more sensitive to mechanical influences ("tapping", etc.). However, for many applications, such as monitors and especially TV screens, it is required to shorten the response time of the display as well as to improve the contrast and the brightness (transmission) of the display.

[0012] Another development is the so-called PS ("Polymer Sustained") or PSA ("Polymer Sustained Alignment") displays, to which occasionally also the term "Polymer Stabilized" is applied. In these, a small amount (e.g. 0.3 wt.-%, typically < 1 wt.-%) of one or more polymerizable compounds, preferably polymerizable monomeric compounds, is added to the LC medium and polymerized or cross-linked in situ (usually by UV photopolymerization) after the LC medium has been filled into the display, while optionally applying a voltage to the electrodes of the display. The polymerization is carried out at temperatures at which the LC medium shows a liquid-crystalline phase, typically at room temperature. It has proven to be particularly suitable to add polymerizable mesogenic or liquid-crystalline compounds (also called reactive mesogens or "RMs") to the LC mixture.

[0013] Unless otherwise indicated, the term "PSA" is used hereinafter when referring to displays of the general polymer sustained alignment type, and "PS" is used when referring to specific display modes like PS-VA, PS-TN etc.

[0014] Furthermore, unless otherwise indicated, the term "RM" is used hereinafter when referring to polymerizable mesogenic or liquid-crystalline compounds.

[0015] At the same time, the PS(A) principle is being used for various conventional LC display modes. Thus, for example, PS-VA, PS-OCB, PS-IPS, PS-FFS, PS-UB-FFS and PS-TN displays are known. The polymerization of the RMs, in the case of PS-VA and PS-OCB displays, preferably takes place under applied voltage, in the case of PS-IPS displays with or without, preferably without, applied voltage. The PS(A) approach leads to a pre-tilt in the cell, as can be verified in test cells. In the case of PS-OCB displays, for example, it can be that the bend structure is stabilized, so that the disclination voltage is not required or can be reduced. In the case of PS-VA displays, the pre-tilt has a positive effect on the response time. For PS-VA displays, standard MVA or PVA pixels and electrode layouts can be used. However, it is also possible, in addition, to manage for example with only one structured electrode side without protrusions, which significantly simplifies production and at the same time leads to very good contrast and very good light transmission.

[0016] Furthermore, so-called positive-VA displays ("positive VA") have proven to be a particularly advantageous mode. Similar to conventional VA displays, in a positive-VA display the initial alignment of the LC molecules in the initial state when no voltage is applied is homeotropic, i.e. substantially perpendicular to the substrates. However, in contrast to conventional VA displays, in a positive-VA display an LC medium having a positive dielectric anisotropy is used. Similar to in commonly used IPS displays, in a positive-VA display the two electrodes are arranged only on one of the two substrates and exhibit a structure which preferably intermeshes and is comb-like (interdigital). By applying a voltage to the interdigital electrodes which generates an electric field which is substantially parallel to the LC medium layer, the LC molecules are converted into an alignment which is substantially parallel to the substrates. In a positive-VA display it has also proven advantageous to polymerise stabilise (by adding a RM which polymerises in the display to the liquid-crystalline medium), whereby a significant shortening of the response times can be achieved.

[0017] PS-VA displays are described, for example, in EP 1 170 626 A2, US 6,861,107, US 7,169,449, US 2004 / 0191428 A1, US 2006 / 0066793 A1 and US 2006 / 0103804 A1. PS-OCB displays are described, for example, in T.-J-Chen et al., Jpn. J. Appl. Phys. 45, 2006, 2702-2704 and S. H. Kim, L.-C-Chien, Jpn. J. Appl. Phys. 43, 2004, 7643-7647. PS-IPS displays are described, for example, in US 6,177,972 and Appl. Phys. Lett. 1999, 75(21 ), 3264. PS-TN displays are described, for example, in Optics Express 2004, 12(7), 1221.

[0018] Under the layer formed by the phase separation and polymerisation of the RM which induces the above-mentioned pretilt angle, PSA displays typically contain an alignment layer, for example an alignment layer of polyimide, which provides the initial alignment of the LC molecules prior to the polymer stabilisation step.

[0019] Frictioned polyimide layers have long been used as alignment layers. The friction method causes a variety of problems, such as inhomogeneity, contamination, electrostatic discharge problems, residues, etc. Therefore, instead of frictioned polyimide layers, it is proposed to use polyimide layers prepared by photoalignment, using the photoinduced directional order of the alignment surface. This can be achieved by means of polarised light, via photodecomposition, photodimerisation or photoisomerisation.

[0020] However, there is still a need for suitably derivatized polyimide layers comprising photoreactive groups. Generally, the effort and costs for producing such polyimide layers, treating the polyimide and modifying the bump or polymer layer are relatively large.

[0021] In addition, it was observed that an adverse interaction of the polyimide alignment layer with certain compounds of the LC medium generally leads to a reduction of the electrical resistance of the display. The number of suitable and usable LC compounds is thus significantly reduced at the expense of display parameters (such as viewing angle dependence, contrast and response time) which are intended to be improved by using such LC compounds. There is thus a need to omit the polyimide alignment layer.

[0022] For some display modes, this is achieved by adding a self-alignment agent or additive to the LC medium which induces the desired alignment, e.g. homeotropic or planar alignment, in situ by a self-assembly mechanism. Thus, an alignment layer on one or both substrates can be omitted. These display modes are also referred to as "self-alignment" or "self-aligned" (SA) modes.

[0023] In SA displays, a small amount (typically 0.1 to 2.5%) of a self-alignment additive is added to the LC medium. Suitable self-alignment additives are, for example, compounds having an organic core group and one or more polar anchoring groups attached thereto which can interact with the substrate surface so that the additive on the substrate surface aligns and also induces the desired alignment in the LC molecules. Preferred self-alignment additives comprise, for example, a mesogenic group and straight-chain or branched alkyl side chains terminated by one or more polar anchoring groups, for example selected from hydroxyl, carboxyl, amino or thiol groups. The self-alignment additive can also contain one or more polymerizable groups which can be polymerized under similar conditions as the RMs used for PSA methods.

[0024] SA-VA displays and SA-FFS displays have been disclosed so far. Suitable self-alignment additives which induce homeotropic alignment, in particular for SA-VA mode displays, are disclosed, for example, in US 2013 / 0182202 A1, US 2014 / 0138581 A1, US 2015 / 0166890 A1 and US 2015 / 0252265 A1.

[0025] SA modes can also be used in combination with PSA modes. The LC medium of a display for such a combined mode thus contains both one or more RMs and one or more self-alignment additives.

[0026] Similar to the above-described conventional LC displays, the PSA displays can be operated as active matrix or passive matrix displays. In case of active matrix displays, the individual pixels are usually addressed by means of integrated non-linear active elements like transistors (e.g. thin film transistors "TFTs"), whereas in case of passive matrix displays, the addressing is usually performed by means of multiplexing methods as known in the art.

[0027] The PSA displays also comprise an alignment layer on one or both substrates forming the display cell. The alignment layer is usually applied to the electrodes, where such electrodes are present, so that it is in contact with the LC medium and induces an initial alignment of the LC molecules. The alignment layer also comprises or consists of, for example, a polyimide, which can also be rubbed, or can be prepared by a photo-alignment method.

[0028] Especially for monitor and especially TV applications, there is a continuous demand for optimization of the response time of liquid crystal displays as well as for contrast and brightness (and thus also for transmittance). The PSA approach can provide a key advantage here. Especially in case of PS-VA, PS-IPS, PS-FFS and PS-Positive-VA-displays, a shortening of the response time in connection with the pre-tilt which is measurable in test cells can be achieved without significant detrimental effects on other parameters.

[0029] The prior art has proposed the use of diphenyl diacrylate or diphenyl dimethacrylate, optionally fluorinated, as RM in PSA displays.

[0030] However, the problem arises that not every combination of an LC mixture and one or more RMs is suitable for a PSA display, because, for example, insufficient or no tilt at all is established, or because, for example, the VHR is not sufficient for TFT display applications. Furthermore, it has been found that the LC mixtures and RMs known from the prior art still have some drawbacks when used in PSA displays. Thus, not every RM known to be soluble in LC mixtures is suitable for use in PSA displays. Furthermore, in addition to a direct measurement of the pre-tilt in a PSA display, it is often difficult to find a suitable selection criterion for the RMs. The selection of a suitable RM becomes even smaller if polymerization by means of UV light without addition of a photoinitiator is desired, which can be advantageous for certain applications.

[0031] In addition, the selected combination of LC host mixture / RM should have as low a rotational viscosity and as optimal electrical properties as possible. In particular, it should have as high a VHR as possible. A high VHR after irradiation with UV light is particularly required in PSA displays, because UV exposure is an indispensable part of the display production process and also occurs as normal exposure during operation of the finished display.

[0032] In particular, it is desirable to provide new materials which are available for PSA displays which produce particularly small tilt angles. Here, preferred materials are those which, during polymerization, produce lower pre-tilt angles for the same exposure time than hitherto known materials, and / or by using which a (higher) pre-tilt angle can also be achieved after a shorter exposure time than has been possible with known materials. Thereby, the production time ("tact time") of the display can be shortened and the costs of the production process can be reduced.

[0033] Another problem in the production of PSA displays is the presence or removal of residual amounts of un-polymerized RM, in particular after the polymerization step for producing the pre-tilt angle in the display. For example, such un-reacted RM can adversely affect the properties of the display by, for example, polymerizing in an uncontrolled manner during operation after the display has been manufactured.

[0034] Thus, PSA displays known from the prior art often show the undesirable effect of so-called "image sticking" or "image burn", i.e. an image produced in an LC display by a brief addressing of individual pixels remains visible even after the electric field in these pixels has been switched off or after other pixels have been addressed.

[0035] If LC host mixtures with a low VHR are used, this "image sticking" can occur on the one hand. The UV-component of daylight or backlights can initiate undesired decomposition reactions of the LC molecules therein and thus the production of ionic or free-radical impurities. These can accumulate, in particular at the electrodes or alignment layers, where they can reduce the effective applied voltage. This effect can also be observed in conventional LC displays without a polymer component.

[0036] In addition, an additional "image sticking" effect due to the presence of un-polymerized RM is often observed in PSA displays. The uncontrolled polymerization of residual RM is initiated here by UV light from the environment or the backlight. Within the switched display regions, this changes the tilt angle after a number of addressing cycles. As a result, a change in the transmission can occur within the switched regions, while it remains unchanged in the un-switched regions.

[0037] Thus, it is desirable that the polymerization of the RM during the production of a PSA display proceeds as completely as possible and that the presence of un-polymerized RM in the display is excluded or reduced to a minimum as far as possible. Therefore, there is a need for RM and LC mixtures which enable or support a highly efficient and complete polymerization of the RM. In addition, it is desirable that the reaction of the residual RM amount is controlled. This would be simpler if the RM polymerized faster and more efficiently than hitherto known materials.

[0038] Another problem observed in the operation of PSA displays is the stability of the tilt angle. Thus, it was observed that the tilt angle, which is generated during the manufacturing of the display by polymerization of the RM as described above, does not remain constant, but deteriorates after the display is subjected to voltage stress during its operation. This can have a negative impact on the display performance, for example by increasing the black state transmittance and thus reducing the contrast.

[0039] Another problem to be solved is that the RMs of the prior art do indeed often have a high melting point and do indeed show only limited solubility in many currently common LC mixtures and thus often tend to crystallize spontaneously out of the mixture. Furthermore, the risk of spontaneous polymerization prevents the LC host mixture from being warmed to dissolve the polymerizable component, which means that the best possible solubility is necessary even at room temperature. In addition, there is the risk of separation, for example when the LC medium is introduced into an LC display (chromatographic effect), which can greatly impair the uniformity of the display. This is further increased by the fact that the LC medium is often introduced at low temperature to reduce the risk of spontaneous polymerization (see above), which in turn has a negative impact on the solubility.

[0040] Another problem observed in the prior art is that the use of conventional LC media in LC displays, including but not limited to PSA type displays, often leads to the occurrence of non-uniformities in the display, especially when the LC medium is filled in display cells manufactured using the One Drop Fill (ODF) method. This phenomenon is also referred to as "ODF non-uniformity". There is thus a need to provide LC media that result in a reduction of ODF non-uniformity.

[0041] Another problem observed in the prior art is that LC media used in PSA displays, including but not limited to displays of the PSA type, often exhibit a high viscosity and, thus, a high switching time. In order to reduce the viscosity and the switching time of the LC medium, it has been proposed in the prior art to add LC compounds having an alkenyl group. However, it was observed that LC media containing alkenyl compounds often show a reduction in reliability and stability, as well as a reduction in VHR, especially after exposure to UV radiation. This is a considerable disadvantage especially for use in PSA displays, since the photopolymerization of the RM in PSA displays is usually carried out by exposure to UV radiation, which can lead to a reduction in VHR in the LC medium.

[0042] There is thus still a great need for PSA displays and LC media and polymerizable compounds for use in such displays that do not show the disadvantages as described above or only to a small extent and have improved properties.

[0043] In particular, there is a great demand for PSA displays and LC media and polymerisable compounds for use in such PSA displays which enable high specific resistance at the same time over a large operating temperature range, short response times even at low temperatures and low threshold voltage, low pretilt angle, large number of grey levels, high contrast and wide viewing angle, and after UV exposure high reliability and high values of (VHR), and in the case of polymerisable compounds, low melting point and high solubility in the LC host mixture. In PSA displays for mobile applications, in particular, there is a need for available LC media which exhibit low threshold voltage and high birefringence.

[0044] In the prior art, several types of RMs for use in PSA displays have been reported, for example RMs having a biphenyl or terphenyl mesogenic core and two or three polymerisable acrylate or methacrylate groups attached thereto. Biphenyl RMs have been shown to exhibit limited polymerisation speed but good reliability parameters, such as high VHR or tilt stability, whereas terphenyl RMs have been shown to exhibit fast polymerisation speed but limited reliability parameters. There is therefore a need for available RMs which exhibit both fast polymerisation speed and good reliability parameters.

[0045] The present application is based on the object of providing novel suitable materials, in particular RMs for use in PSA displays and LC media comprising the same, which do not have or to a lesser extent have the above- indicated disadvantages.

[0046] In particular, the present application is based on the object of providing RMs for use in PSA displays and LC media comprising the same which enable very high specific resistance values, high VHR values, high reliability, low threshold voltage, short response times, high birefringence, exhibit good UV absorption, in particular at longer wavelengths, enabling fast and complete polymerisation of the RMs, enabling low pretilt angles to be produced as quickly as possible, high stability of the tilt angle even after longer periods and / or after UV exposure, reduction or prevention of the occurrence of "image sticking" and "ODF inhomogeneity" in the display, and in the case of the RMs, as fast and complete polymerisation as possible, and high solubility in the LC media which are typically used as host mixtures in PSA displays.

[0047] A further object of the present application is to provide RMs for use in PSA displays which exhibit both fast polymerisation speed and good reliability parameters, such as high VHR or tilt stability.

[0048] A further object of the present application is to provide novel RMs, in particular for use in optical, electro-optical and electronic applications; and suitable methods and intermediates for their preparation.

[0049] A further object of the present application is to provide RMs which display one or more of the following advantageous effects:

[0050] - are able to generate a stable pre-tilt angle to a desired extent after exposure to UV light,

[0051] - the time range of the first UV step to generate a pre-tilt angle can be well controlled during the UV treatment,

[0052] - the time range of the second UV step can be kept as short as possible to minimize production costs,

[0053] - the residual RM has no any negative effect on the performance parameters of the LC mixture, i.e. VHR, tilt stability, etc. after the first and second UV exposure steps,

[0054] - have a good solubility and stability in the LC mixture over a wide temperature range, typically from -40°C to 140°C,

[0055] - when used in displays for SA-VA mode, the RMs can form a polymer layer with low reflectivity after UV treatment together with SA-VA additives.

[0056] One or more of these objectives have been achieved according to the present application by materials and methods as described in the present application. In particular, it has been surprisingly found that the use of RMs of formula I as described hereinafter makes it possible to achieve the advantageous effects as mentioned above. These compounds are characterized in that they contain an aromatic mesogenic core which comprises an alkylene-fluorenyl group and one or more polymerizable reactive groups attached thereto.

[0057] It has been surprisingly found that the use of these RMs and LC media comprising the same in PSA displays, particularly at longer UV wavelengths in the range of 300-380 nm and especially greater than 320 nm, even without the addition of photoinitiators, promotes a fast and complete UV photopolymerization reaction; leads to a fast generation of low and stable tilt angles; reduces image sticking and ODF inhomogeneity in the display, resulting in high reliability and high VHR values after UV photopolymerization, especially in the case of LC host mixtures containing LC compounds with alkenyl groups; and enables fast response times, low threshold voltages, and high birefringence.

[0058] In addition, the RMs according to the present application have a low melting point, good solubility, and have a low tendency to generate crystallization in a wide range of LC media for PSA applications, especially in commercially available LC host mixtures. Furthermore, they exhibit a good absorption at longer UV wavelengths, particularly in the range of 300-380 nm, and enable fast and complete polymerization with a small amount of residual, unreacted RM in the cell.

[0059] It was also surprisingly found that the RM combinations of the present application combine a fast polymerization speed (as for the terphenyl RMs) with good reliability parameters (as for the biphenyl RMs). This results in superior overall performance compared to the RMs of the prior art.

[0060] The present application relates to compounds of formula I,

[0061]

[0062] wherein each radical, independently of each other and on each occurrence identically or differently, has the following meanings:

[0063] A is a monocyclic, bicyclic or polycyclic aromatic or heteroaromatic radical having 10 to 30 ring atoms, which can also contain fused rings,

[0064] P is on each occurrence identically or differently a polymerizable group,

[0065] Sp is on each occurrence identically or differently a spacer group, optionally substituted by one or more radicals P, or a single bond,

[0066] L a is an aromatic or heteroaromatic radical having 4 to 30 ring atoms, which can also contain fused rings, and is optionally substituted by one or more radicals L,

[0067] L is F, Cl, Br, -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-, -N(R 0 )-, -Si(R 0 R 00 )-, -CH=CH- or -C≡C- in such a way that 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 or Cl,

[0068] a is 1, 2, 3 or 4, preferably 1 or 2,

[0069] b is 0, 1, 2, 3, 4, 5 or 6, preferably 0, 1 or 2,

[0070] with the proviso that if A is a biphenylene group, a is 2, b is 0 and Sp is a single bond, then L a is different from unsubstituted benzene.

[0071] The present application also relates to the use of the compounds of formula I as polymerizable compounds in LC media and LC displays, in particular in the LC medium, the active layer or the alignment layer of an LC display, which is preferably a PSA display.

[0072] The present application further relates to processes for preparing compounds of formula I, and novel intermediates used or obtained in these processes.

[0073] The present application additionally relates to LC media comprising one or more compounds of formula I.

[0074] The present application additionally relates to LC media comprising one or more polymerisable compounds, at least one of which is a compound of formula I.

[0075] The present application additionally relates to LC media comprising:

[0076] - a polymerisable component A) comprising, preferably consisting of, one or more polymerisable compounds, at least one of which is a compound of formula I, and

[0077] - a liquid-crystalline component B), hereinafter also referred to as "LC host mixture", comprising, preferably consisting of, one or more mesogenic or LC compounds.

[0078] The liquid-crystalline component B) of the LC medium according to the present application is hereinafter also referred to as "LC host mixture" and preferably comprises one or more, preferably at least two, mesogenic or LC compounds selected from non-polymerisable low-molecular weight compounds.

[0079] The present application also relates to the LC medium as described above and below, wherein the LC host mixture or component B) comprises at least one mesogenic or LC compound comprising alkenyl groups.

[0080] The present application also relates to the LC medium or LC display as described above, wherein the compound of formula I or the polymerisable compounds of component A) are polymerised.

[0081] The present application also relates to a process for preparing the LC medium as described above and below, comprising the step of mixing one or more mesogenic or LC compounds, or LC host mixture or LC component B) as described above and below, with one or more compounds of formula I, and optionally with further LC compounds and / or additives.

[0082] The present application also relates to the use of the compounds of formula I and the LC medium according to the present application in PSA displays, in particular in PSA displays containing the LC medium, for generating an angle of tilt in the LC medium by in-situ polymerisation of the compound(s) of formula I, preferably in an electric or magnetic field, in the display.

[0083] The application also relates to an LC display, in particular a PSA display, very particularly preferably a PS-VA, PS-OCB, PS-IPS, PS-FFS, PS-UB-FFS, PS- positive-VA or PS-TN display, comprising one or more compounds of the formula I or an LC medium according to the application.

[0084] The application furthermore relates to the use of the compounds of the formula I and the LC medium according to the application in a polymer stabilised SA display, in particular in a polymer stabilised SA-VA and SA-FFS display, and to a polymer stabilised SA, SA-VA or SA-HB-FFS display comprising one or more compounds of the formula I or an LC medium according to the application.

[0085] The application furthermore relates to an LC display comprising a polymer obtainable by polymerisation of one or more compounds of the formula I or polymerisable components A) as described above, or comprising an LC medium according to the application, which is preferably a PSA or a polymer stabilised SA display, very particularly preferably a PS-VA, PS-OCB, PS-IPS, PS-FFS, PS-UB-FFS, PS- positive-VA, PS-TN or a polymer stabilised SA-VA or SA-HB-FFS display.

[0086] The application furthermore relates to an LC display of the PSA type, comprising two substrates, at least one of which is light-transmitting, electrodes provided on each substrate or two electrodes provided on only one of the substrates and a layer of an LC medium located between the substrates, which LC medium comprises one or more polymerisable compounds and LC components as described above and below, wherein the polymerisable compounds are polymerised between the substrates of the display.

[0087] The application furthermore relates to a process for producing an LC display as described above and below, comprising the steps of filling or otherwise providing an LC medium comprising one or more polymerisable compounds as described above and below between the substrates of the display and polymerising the polymerisable compounds.

[0088] The PSA display according to the application has two electrodes, preferably in the form of transparent layers, which are applied to one or both of the substrates. In some displays, for example in PS-VA, PS-OCB, PS-TN or polymer stabilised SA-VA displays, one electrode is applied to each of the two substrates. In other displays, for example in PS-positive-VA, PS-IPS or PS-FFS, PS-UB-FFS or polymer stabilised SA-FFS displays, two electrodes are applied to only one of the two substrates.

[0089] In a preferred embodiment, the polymerisable components are polymerised in the LC display while applying a voltage to the electrodes of the display.

[0090] The polymerisable compounds of the polymerisable components are preferably polymerised by photopolymerisation, very preferably by UV photopolymerisation.

[0091] It is considered that the alkenyl groups of the compounds of formula I as disclosed and claimed in the present application are not within the meaning of the term "polymerisable group" as used herein. Preferably, the LC media disclosed and claimed in the present application do not contain additives that initiate or enhance the participation of alkenyl groups in polymerisation reactions.

[0092] Furthermore, the present application relates to compounds of formula IN

[0093]

[0094] wherein Pg denotes, on each occurrence, identically or differently, OH or a protected or masked OH group, and A, Sp, L a , L, a and b have the meaning of formula I or one of the preferred meanings above and below.

[0095] The present application furthermore relates to the use of compounds of formula IN as intermediates in the synthesis of polymerisable compounds, especially those of formula I.

[0096] The present application furthermore relates to a process for the synthesis of compounds of formula I, which is carried out by esterification or etherification of compounds of formula IN using corresponding acids, acid derivatives or halogenated compounds containing the polymerisable group P, wherein Pg denotes OH.

[0097] When used in PSA displays, the compounds of formula I exhibit the following advantageous properties:

[0098] - suitable tilt generation within a process window,

[0099] - fast polymerisation with minimal residual RM after UV treatment,

[0100] - high voltage holding ratio after UV treatment

[0101] - good tilt stability,

[0102] - sufficient thermal stability,

[0103] - sufficient solubility in organic solvents typically used in display manufacturing.

[0104] Furthermore, the compounds of formula I allow to solve one or more of the following problems:

[0105] - stable tilt angles of the desired angle are generated after exposure to UV light,

[0106] - controlling the time frame of the first UV step producing a pre-tilt angle during the UV treatment,

[0107] - making the time frame of the second UV step as short as possible to minimize production costs,

[0108] - reducing or avoiding any negative impact of residual RM on the performance parameters of the LC mixture such as VHR, tilt stability etc. after the first and second UV exposure step,

[0109] - providing good solubility and stability in the LC host mixture over a broad temperature range from preferably -40°C to about 140°C,

[0110] - providing a RM which can form a polymer layer with low reflectivity after UV treatment together with SA-VA additives for use in SA-VA displays.

[0111] In particular, the compounds of formula I combine the fast polymerization speed of a terphenyl RM with the good reliability parameters of a biphenyl RM. This leads to superior overall performance of the compounds compared to state-of-the-art RMs for use in PSA displays.

[0112] It is considered that the alkenyl groups of the compounds of formula as disclosed and claimed in the present application are not within the meaning of the term "polymerizable group" as used herein. The polymerization conditions of the compounds of formula I are preferably chosen such that the alkenyl substituents do not participate in the polymerization reaction. Preferably, the LC media disclosed and claimed in the present application do not contain additives which initiate or enhance the participation of alkenyl groups in the polymerization reaction.

[0113] Unless otherwise indicated, the compounds of formula I are preferably selected from the group of achiral compounds.

[0114] As used herein, the terms "active layer" and "switchable layer" mean a layer comprising one or more molecules having structural and optical anisotropy, for example LC molecules, in an electro-optical display, for example in an LC display, which molecules change their orientation when subjected to an external stimulus, for example an electric or magnetic field, which leads to a change in the transmission of polarized or non-polarized light by the layer.

[0115] As used herein, the terms "tilt" and "tilt angle" are to be understood to denote a tilted alignment of the LC molecules of the LC medium relative to the surfaces of the cell in an LC display, here preferably a PSA display, and are to be understood to include "pre-tilt" and "pre-tilt angle". The tilt angle here denotes the average angle (< 90°) between the longitudinal molecular axis of the LC molecules (LC director) and the plane parallel to the outer plates forming the LC cell. A low absolute value of the tilt angle here, i.e. a large deviation from the 90° angle, corresponds to a large tilt. A suitable method for measuring the tilt angle is given in the Examples. Unless otherwise specified, the tilt angle values disclosed in the context are related to this method of measurement.

[0116] As used herein, the terms "reactive mesogen" and "RM" are to be understood to denote a compound comprising a mesogenic or liquid crystalline backbone, and one or more functional groups attached thereto which are suitable for polymerization, and which are also referred to as "polymerizable groups" or "P".

[0117] Unless otherwise specified, the term "polymerizable compound" as used herein is to be understood as a monomeric compound which is polymerizable.

[0118] The SA-VA or SA-FFS according to the present application will have a polymer stabilized mode, since it contains an LC medium containing RMs of formula I or is manufactured by using the same. Thus, as used herein, the terms "SA-VA display" and "SA-FFS display" when referring to a display according to the present application are to be understood to mean a polymer stabilized SA-VA or SA-FFS display, even if not explicitly mentioned.

[0119] As used herein, the term "low molecular weight compound" is to be understood to denote a compound which is monomeric and / or not prepared by a polymerization reaction, which is opposed to a "polymeric compound" or "polymer".

[0120] As used herein, the term "non-polymerizable compound" is to be understood to denote a compound which does not contain a functional group which is suitable for polymerization under the conditions usually applied to the polymerization of RMs.

[0121] As used herein, the term "mesogenic group" is known to the person skilled in the art and described in the literature and it denotes a group which contributes essentially to the generation of a liquid crystalline (LC) phase in low-molecular-weight or polymeric substances due to its anisotropy of attraction and repulsion interactions. A compound comprising a mesogenic group (mesogenic compound) does not necessarily have an LC phase itself. A mesogenic compound can also exhibit LC phase behaviour only after mixing with other compounds and / or after polymerisation. Typical mesogenic groups are, for example, rigid rod-like or disc-like units. The 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.

[0122] As used herein, the term "spacer group" (hereinafter also referred to as "Sp") is known to the person skilled in the art and 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 group" or "spacer" denotes a flexible group, for example it is an alkylene group, which is attached to a mesogenic group or to a polymerisable group(s) in a polymerisable mesogenic compound.

[0123] In the above and in the following, denotes a trans-1,4-cyclohexylene ring, and denotes a 1,4-phenylene ring.

[0124] In the group the single bond shown between two ring atoms can be attached to any free position of the phenyl ring.

[0125] "Halogen" denotes F, CI, Br or I, preferably F or CI.

[0126] -CO-, -C(=0)- and -C(O)- denote a carbonyl group, i.e.

[0127] The terms "alkyl", "aryl", "heteroaryl" and the like also include polyvalent groups, such as alkylene, arylene, heteroarylene and the like.

[0128] If in the formulae shown above and below, the groups R 1-13 , R 21 , R 31 , R 41 , 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 denotes alkyl and / or alkoxy, this can be straight-chain or branched. It is preferably straight-chain with 2, 3, 4, 5, 6 or 7 C atoms and thus preferably denotes ethyl, propyl, butyl, pentyl, hexyl, heptyl, ethoxy, propoxy, butoxy, pentoxy, hexoxy or heptoxy, furthermore methyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, methoxy, octyloxy, nonyloxy, decyloxy, undecyloxy, dodecyloxy, tridecyloxy or tetradecyloxy.

[0129] If in the formulae shown above and below the radical 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 denotes alkyl in which one or more CH2groups are replaced by S, this can be straight-chain or branched. It is preferably straight-chain with 1, 2, 3, 4, 5, 6 or 7 C atoms and thus preferably denotes thiomethyl, thioethyl, thiopropyl, thiobutyl, thiopentyl, thiohexyl or thioheptyl.

[0130] Oxaalkyl preferably denotes 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-oxanonyl, 2-, 3-, 4-, 5-, 6-, 7-, 8- or 9-oxadecyl.

[0131] If in the formulae shown above and below the radical R 1-13 R 51 R 52 R QR, R 2A R 2B R IIIA R 1N R 2N R B1 R B2 R CR1 R CR2 R or L represent alkoxy or oxaalkyl, it can also contain one or more additional oxygen atoms, provided that the oxygen atoms are not directly connected to one another.

[0132] 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 R or L is selected from the group consisting of: -S 1 -F, -O-S 1 -F, -O-S1-O-S2, wherein S 1 is C 1-12 -alkylene or C 2-12 -alkenylene and S 2 is H, C 1-12 -alkyl or C 2-12 -alkenyl, and very preferably selected from the group consisting of: -OCH2OCH3, -O(CH2)2OCH3, -O(CH2)3OCH3, -O(CH2)4OCH3, -O(CH2)2F, -O(CH2)3F, -O(CH2)4F.

[0133] If in the above and below shown formulae 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 CR2R or L indicates that one of the CH2 groups is an alkyl group replaced by -CH=CH-, which can be straight-chain or branched. It is preferably straight-chain and has 2 to 10 carbon atoms. Therefore, specifically, it represents 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, hep-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.

[0134] If in the formula shown above and below, 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 that is at least monosubstituted with a halogen, in which case the group is preferably straight-chain, and the halogen is preferably F or Cl. In the case of multiple substitution, the halogen is preferably F. The resulting group also includes a perfluorinated group. In the case of monosubstitution, the fluorine or chlorine substituent can be at any desired position, but is preferably at the ω position.

[0135] Preferred alkyl groups include, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, 2-methylbutyl, n-pentyl, sec-pentyl, cyclopentyl, n-hexyl, cyclohexyl, 2-ethylhexyl, n-heptyl, cycloheptyl, n-octyl, cyclooctyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, dodecyl, trifluoromethyl, perfluoron-butyl, 2,2,2-trifluoroethyl, perfluorooctyl, perfluorohexyl, etc.

[0136] Preferred alkenyl groups include, for example, vinyl, propenyl, butenyl, pentenyl, cyclopentenyl, hexenyl, cyclohexenyl, heptenyl, cycloheptenyl, octenyl, cyclooctenyl, etc.

[0137] Preferred alkynyl groups include, for example, ethynyl, propynyl, butynyl, penynyl, hexynyl, octyynyl, etc.

[0138] Preferred alkoxy groups are, for example, methoxy, ethoxy, 2-methoxyethoxy, n- propoxy, isopropoxy, n-butoxy, isobutoxy, sec-butoxy, tert-butoxy, 2-methylbutoxy, n- pentoxy, n-hexyloxy, n-heptyloxy, n-octyloxy, n-nonyloxy, n-decanyloxy, n-undecyloxy, n-dodecyloxy and the like.

[0139] Aromatic and heteroaromatic groups can be monocyclic or polycyclic, i.e. they can contain one ring (e.g. phenyl) or two or more rings, which can also be fused (e.g. naphthyl) or covalently bound (e.g. biphenyl), or comprise a combination of fused and linked rings. Heteroaromatic groups contain one or more heteroatoms, preferably selected from O, N, S and Se.

[0140] Particularly preferred are mono-, bi- or tricyclic aromatic groups having 6 to 25 C atoms and mono-, bi- or tricyclic heteroaryl groups having 5 to 25 ring atoms, which optionally contain fused rings and are optionally substituted. Further preferred are 5-, 6- or 7-membered aromatic and heteroaromatic groups, wherein, in addition, one or more CH groups can be replaced by N, S or O in such a way that the O and / or S atoms are not directly linked to one another.

[0141] Preferred aromatic groups are, for example, phenyl, biphenyl, terphenyl, [1,1 ':3',1 "] -terphenyl-2'-yl, naphthyl, anthryl, binaphthyl, phenanthryl, 9,10-dihydro-phenanthryl, pyrenyl, dihydropyrenyl, pyromethene, perylene, tetracene, pentacene, benzopyrene, fluorene, indene, indenofluorene, spirobifluorene and the like.

[0142] Preferred heteroaromatic groups are, for example, 5-membered rings, such as pyrrole, pyrazole, imidazole, 1,2,3-triazole, 1,2,4-triazole, tetrazole, furan, thiophene, selenophene, oxazole, isoxazole, 1,2-thiazole, 1,3-thiazole, 1,2,3-oxadiazole, 1,2,4-oxadiazole, 1,2,5-oxadiazole, 1,3,4-oxadiazole, 1,2,3-thiadiazole, 1,2,4-thiadiazole, 1,2,5-thiadiazole, 1,3,4-thiadiazole, 6-membered rings, such as pyridine, pyridazine, pyrimidine, pyrazine, 1,3,5-triazine, 1,2,4-triazine, 1,2,3-triazine, 1,2,4,5-tetrazine, 1,2,3,4-tetrazine, 1,2,3,5-tetrazine, or fused groups, such as indole, isoindole, indolizine, indazole, benzimidazole, benzotriazole, purine, naphthoimidazole, phenanthroimidazole, pyridoimidazole, pyrazimoimidazole, quinoxaloimidazole, benzoxazole, naphthoxazole, anthroxazole, phenanthroxazole, isoxazole, benzothiazole, benzofuran, isobenzofuran, dibenzofuran, quinoline, isoquinoline, pteridine, benzo-5,6-quinoline, benzo-6,7-quinoline, benzo-7,8-quinoline, benzoisoquinoline, acridine, phenothiazine, phenoxazine, benzopyridazine, benzopyrimidine, quinoxaline, phenazine, naphthylidine, azacarbazole, benzocarbolin, phenanthridine, phenanthroline, thieno[2,3b]thiophene, thieno[3,2b]thiophene, dithienothiophene, isobenzothiophene, dibenzothiophene, benzothiophene, benzothiadiazolothiophene, or combinations of these groups.

[0143] The aryl and heteroaryl groups mentioned above and below can also be substituted by alkyl, alkoxy, thioalkyl, fluoro or fluoroalkyl, or by alicyclyl, heterocyclyl, aryl or heteroaryl.

[0144] Preferred (non-aromatic) alicyclyl and heterocyclyl groups comprise both saturated rings, i.e. rings containing only single bonds, and partially unsaturated rings, i.e. those which can also contain multiple bonds. The heterocycle contains one or more heteroatoms, preferably selected from Si, O, N, S and Se.

[0145] Preferred (non-aromatic) alicyclyl and heterocyclyl groups can be monocyclic, i.e. contain only one ring (e.g. cyclohexane), or polycyclic, i.e. contain multiple rings (e.g. decalin or bicyclooctane). Particular preference is given to saturated groups. Preference is furthermore given to mono-, bi- or tricyclic radicals having 5 to 25 ring atoms, which optionally contain fused rings and are optionally substituted. Further preference is given to 5-, 6-, 7- or 8-membered carbocyclic radicals, wherein, in addition, one or more C atoms can be replaced by Si and / or one or more CH groups can be replaced by N and / or one or more non-adjacent CH2 groups can be replaced by -O- and / or -S-.

[0146] Preferred aliphatic and heterocyclic groups are, for example, 5-membered groups, such as cyclopentane, tetrahydrofuran, tetrahydrothiophene, pyrrolidine; 6-membered groups, such as cyclohexane, silinane, cyclohexene, tetrahydropyran, tetrahydrothiopyran, 1,3-dioxane, 1,3-dithiane, piperidine; 7-membered groups, such as cycloheptane; and fused groups, such as tetrahydronaphthalene, decahydronaphthalene, indane, bicyclo[1.1.1 ]pentane-1,3-diyl, bicyclo[2.2.2]octane-1,4-diyl, spiro[3.3]heptane-2,6-diyl, octahydro-4,7- methanoindane-2,5-diyl.

[0147] Preferred substituents on aryl and heteroaryl groups are also referred to below as "L S ", are, for example, F, CI, Br, I, -CN, -N02, -NCO, -NCS, -OCN, -SCN, -C(=0)N(R x )2, -C(=0)Y 1 , -C(=0)R x , -N(R x )2, straight chain or branched alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy with 1 -25 C atoms, wherein one or more H atoms can optionally be replaced by F or CI, optionally substituted silyl with 1 to 20 Si atoms, or optionally substituted aryl with 6 to 25, preferably 6 to 15 C atoms,

[0148] wherein R x denotes H, F, CI, CN, or straight chain, branched or cyclic alkyl with 1 to 25 C atoms, wherein one or more non-adjacent CH2-groups are optionally replaced, by -0-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O- in such a way that the O- and / or S-atoms are not directly adjacent to each other, and wherein one or more H atoms are each optionally replaced by F, CI, P- or P-Sp- and

[0149] Y 1 denotes halogen.

[0150] "Substituted silyl or aryl" preferably denotes that it is substituted by halogen, -CN, R 0 , -OR 0 , -CO-R 0 , -CO-O-R 0 , -O-CO-R 0 or -O-CO-O-R 0 , wherein R 0 denotes H or alkyl with 1 to 20 C atoms.

[0151] Particularly preferred substituents L are S for example F, CI, CN, N02, CH3, C2H5, OCH3, OC2H5, COCH3, COC2H5, COOCH3, COOC2H5, CF3, OCF3, OCHF2, OC2F5, furthermore phenyl.

[0152] Preferably

[0153] where L has one of the meanings indicated above.

[0154] The polymerisable group P is a group suitable for a polymerisation reaction (for example a radical or ionic chain polymerisation, an addition polymerisation or a condensation polymerisation) or for a polymer-analogous reaction (for example an addition or condensation on a polymer backbone). Particularly preferred are groups for chain polymerisation, in particular those containing a C=C double bond or a -C≡C- triple bond, and groups suitable for ring-opening polymerisation, for example oxetane or epoxy groups.

[0155] Preferred groups P are selected from the group consisting of CH2=CW 1 -CO-O-, CH2=CW 1 -CO-, 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 W4 W 5 W 6 Si-, wherein W 1 represents H, F, CI, CN, CF3, phenyl or alkyl having 1 to 5 C atoms, in particular H, F, CI or CH3, W 2 and W 3 each, independently of one another, represent 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 of one another, represent CI, oxaalkyl or oxacarbonylalkyl having 1 to 5 C atoms, W 7 and W 8 each, independently of one another, represent H, CI or alkyl having 1 to 5 C atoms, Phe represents 1,4-phenylene, which is optionally substituted by one or more groups L as defined above, different from P-Sp-, k1, k2 and k3 each, independently of one another, represent 0 or 1, k3 preferably represents 1, and k4 represents an integer from 1 to 10.

[0156] Very preferred groups P are selected from the group consisting of CH2=CW 1 -CO-O-, CH2=CW 1 -CO-, CH2=CW 2 -O-, CH2=CW 2 -, 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-, wherein W 1 represents H, F, CI, CN, CF3, phenyl or alkyl having 1 to 5 C atoms, in particular H, F, CI or CH3, W 2 and W3 each, independently of one another, denotes 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 of one another, denotes Cl, oxaalkyl or oxacarbonylalkyl having 1 to 5 C atoms, W 7 and W 8 each, independently of one another, denotes H, Cl or alkyl having 1 to 5 C atoms, Phe denotes 1,4-phenylene, k1, k2 and k3 each, independently of one another, denote 0 or 1, k3 preferably denotes 1, and k4 denotes an integer from 1 to 10.

[0157] Very preferred groups P are selected from the group consisting of CH2=CW 1 -CO-O-, in particular CH2=CH-CO-O-, CH2=C(CH3)-CO-O- and CH2=CF-CO-O-, also CH2=CH-O-, (CH2=CH)2CH-O-CO-, (CH2=CH)2CH-O-,

[0158] Other particularly preferred polymerisable groups P are selected from the group consisting of vinyloxy, acrylate, methacrylate, fluorinated acrylate, chlorinated acrylate, oxetane and epoxy, most preferably from acrylate and methacrylate.

[0159] If the spacer group Sp is different from a single bond, it is preferably of the formula Sp"-X", such that each group P-Sp- corresponds to the formula P-Sp"-X"-, wherein

[0160] Sp" denotes a straight-chain or branched alkylene group having 1 to 20, preferably 1 to 12 C atoms, which is optionally mono- or poly-substituted by F, Cl, Br, I or CN, and wherein, in addition, one or more non-adjacent CH2 groups are each independently of one another replaced by -O-, -S-, -NH-, -N(R 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- in such a way that O and / or S atoms are not directly linked to one another,

[0161] 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 single bonds

[0162] R 0 and R 00 Each independently represents H or an alkyl group having 1-20 carbon atoms, and

[0163] Y 2 and Y 3 Each can be represented independently as H, F, Cl, or CN.

[0164] X" is preferably -O-, -S-, -CO-, -COO-, -OCO-, -O-COO-, or -CO-NR. 0 -、-NR 0 -CO-、-NR 0 -CO-NR 00 - or a single key.

[0165] 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 - where p1 is an integer from 1 to 12, q1 is an integer from 1 to 3, and R 0 and R 00 It has the meaning mentioned above.

[0166] Especially 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 indicated above.

[0167] Especially preferred groups Sp" are in each case straight-chain ethylene, propylene, butylene, pentylene, hexylene, heptylene, octylene, nonylene, decylene, undecylene, dodecylene, octadecylene, ethyleneoxyethylene, methyleneoxybutylene, ethylenethioethylene, ethylene-N-methylimino-ethylene, 1 -methylalkylene, ethenylene, propenylene and butenylene.

[0168] In a preferred embodiment of the present application, the compounds of the formula I and the subformulae thereof contain a spacer group Sp which is substituted by one or more polymerisable groups P, such that the group Sp-P corresponds to Sp(P) s , s is > 2 (branched polymerisable groups).

[0169] Preferred compounds of the formula I according to this preferred embodiment are those in which s is 2, i.e. compounds containing the group Sp(P)2. Very preferred compounds of the formula I according to this preferred embodiment contain a group selected from the following formulae:

[0170] -X-alkyl-CHPP S1

[0171] -X-alkyl-CH((CH2) aa P)((CH2) bb P) S2

[0172] -X-N((CH2) aa P)((CH2) bb P) S3

[0173] -X-alkyl-CHP-CH2-CH2P S4

[0174] -X-alkyl-C(CH2P)(CH2P)-C aa H 2aa+1 S5

[0175] -X-alkyl-CHP-CH2P S6

[0176] -X-alkyl-CPP-C aa H 2aa+1 S7

[0177] - X-alkyl-CHPCHP-C aa H 2aa+1 S8

[0178] wherein P is defined as in formula I,

[0179] alkyl denotes a single bond or a straight-chain or branched alkylene group having 1 to 12 C atoms which is unsubstituted or mono- or poly-substituted by F, Cl or CN, and wherein one or more non-adjacent CH2groups can each be replaced, independently of one another, by -C(R 0 ) = C(R 0 )-, -C≡C-, -N(R 0 )-, -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O-, 0 have the meanings indicated above,

[0180] aa and bb each, independently of one another, denote 0, 1, 2, 3, 4, 5 or 6,

[0181] X has one of the meanings indicated for X", and is preferably O, CO, SO2, O-CO-, CO-O or a single bond.

[0182] Preferred spacer groups Sp(P)2are selected from the group consisting of formulae S1, S2 and S3.

[0183] Very preferred spacer groups Sp(P)2are selected from the following subformulae:

[0184] -CHPP S1a

[0185] -O-CHPP S1b

[0186] -CH2-CHPP S1c

[0187] -OCH2-CHPP S1d

[0188] -CH(CH2-P)(CH2-P) S2a

[0189] -OCH(CH2-P)(CH2-P) S2b

[0190] -CH2-CH(CH2-P)(CH2-P) S2c

[0191] -OCH2-CH(CH2-P)(CH2-P) S2d

[0192] -CO-NH((CH2)2P)((CH2)2P) S3a

[0193] In the compounds of the formula I and the subformulae thereof as described above and below, P is preferably selected from the group consisting of vinyloxy, acrylate, methacrylate, fluoropropenoate, chloropropenoate, oxetane and epoxide, most preferably from acrylate and methacrylate.

[0194] More preferred are the compounds of the formula I and the subformulae thereof as described above and below, wherein all polymerizable groups P present in the compounds have the same meaning and very preferably denote acrylate or methacrylate, most preferably methacrylate.

[0195] In the compounds of the formula I and the subformulae thereof as described above and below, Sp preferably denotes 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 pi is 2, 3, 4, 5 or 6, p2 and p3 independently of one another are 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 the CO-group, respectively, is attached to the phenyl ring.

[0196] Further preferred are the compounds of the formula I and the subformulae thereof as described above and below, wherein at least one group Sp is a single bond.

[0197] Further preferred are the compounds of the formula I and the subformulae thereof as described above and below, wherein 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 pi is 2, 3, 4, 5 or 6, p2 and p3 independently of one another are 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 the CO-group, respectively, is attached to the phenyl ring.

[0198] In the compounds of the formula I and the subformulae thereof as described above and below, L aPreferably selected from the group consisting of benzene, furan, thiophene, pyridine, pyrimidine, pyrazine and naphthalene, very preferably selected from the group consisting of benzene, furan and thiophene, optionally substituted by one or more groups L and preferably unsubstituted.

[0199] Especially preferred are compounds of formula I, wherein a is 1 or 2, very preferably 1.

[0200] Further preferred are compounds of formula I, wherein b is 0, 1 or 2, very preferably 0.

[0201] Further preferred are compounds of formula I selected from subformula IA

[0202] P-Sp-A 1 -(A 2 ) c -Sp-P IA

[0203] wherein A 1 , A 2 independently of one another denote phenylene, naphthalene, phenanthrene, anthracene, dibenzofuran, dibenzothiophene or carbazole, preferably phenylene or naphthalene, very preferably 1,4-phenylene, all optionally substituted by one or two groups L as defined above and below, and c is 0, 1, 2 or 3, preferably 1 or 2, and wherein at least one of A 1 and A 2 is substituted by one or two groups L as defined above and below. a

[0204] Further preferred are compounds of formula I or IA, wherein A or A 1 -(A 2 ) c is selected from the group consisting of 1,4-phenylene, biphenylene (phenylphenyl), p-biphenyltrivylene (1,4-diphenylphenyl), m-biphenyltrivylene (1,3-diphenylphenyl), naphthylene, 2-phenyl-naphthylene, phenanthrene or anthracene, dibenzofuran or dibenzothiophene, very preferably biphenylene or p-biphenyltrivylene, most preferably biphenylene, all substituted by one or two groups L a and optionally substituted by one or two groups L as defined above and below.

[0205] Further preferred compounds of formula I are selected from the following substructures

[0206]

[0207] wherein P, Sp and L have the meaning given in formula I or one of its preferred meanings as given above and below, a is 1 or 2, b is 0, 1 or 2, Ar has the meaning of L a ​one of the meanings given in formula I, I 1, I2, I 3 or one of the preferred meanings thereof given above and below, a1, a2, a3, a4 and a5 are independently from each other 0, 1 or 2, wherein a1 +a2>0 and preferably a1 +a2=1 or 2, a3+a4+a5>0 and preferably a3+a4+a5=1 or 2, b1, b2, b3, b4 and b5 are independently from each other 0, 1 or 2, wherein preferably b1 +b2=0, 1 or 2 and preferably b3+b4+b5=0, 1 or 2.

[0208] Further preferred compounds of formula I are selected from the following substructures

[0209]

[0210]

[0211]

[0212]

[0213]

[0214]

[0215]

[0216]

[0217] wherein Ar, P, Sp, L, b, b1, b3, b4 and b5 independently from each other have one of the meanings given in formula I, I 1, I2, I 3 or one of the preferred meanings thereof given above and below.

[0218] Very preferred are compounds of formula I2-1 to I2-6, most preferred are compounds of formula I2-1, I2-2 and I2-4.

[0219] Further preferred compounds of formula I, IA, I1, I2, I 3, I 1-1, I1-2, I2-1 to I2-6, I 3-1 to I 3-11 and I4-1 to I4-16 are selected from those of one or more of the following embodiments:

[0220] - if in formula I A is biphenyl, a is 1 and / or L a different from unsubstituted phenyl and preferably different from phenyl,

[0221] - if in formula IA c is 1 and A 1 and A 2 is phenylene, only one of A 1 and A 2 is substituted by L a and / or La Unlike unsubstituted benzene, and preferably unlike benzene,

[0222] - In formula I2, a1+a2=1 and / or b1+b2>0 and / or Ar is different from unsubstituted benzene and preferably different from benzene.

[0223] - In formula I2-4, Ar is different from unsubstituted benzene and preferably different from benzene.

[0224] - The P groups independently represent acrylates or methacrylates, very preferably methacrylates.

[0225] -Sp is a single bond.

[0226] - At least one of the Sp groups, preferably exactly one, is a single bond, and the other Sp groups are not single bonds.

[0227] -Sp, when different from a single bond, represents an alkylene group with 2 to 6 carbon atoms or an alkenyl group with 2 to 6 carbon atoms.

[0228] -Sp is substituted by at least one group P, and -Sp-P is selected from formulas S1 to S8 or S1a to S3a as defined above.

[0229] - The Ar groups independently represent benzene, furan, or thiophene, very preferably benzene, which may optionally be substituted by one or more L groups as defined above and below.

[0230] -b, or the sum of b1+b2 or the sum of b3+b4+b5, are either 0 or 1, preferably 0.

[0231] -b, or the sum of b1+b2 or the sum of b3+b4+b5 is 1 or 2, preferably 1, and L is selected from F, Cl, Br, CN, alkyl, alkoxy, alkyl carbonyl, alkoxy carbonyl, alkyl carbonyloxy or alkoxy carbonyloxy or alkenyl having 2 to 6 C atoms, wherein one or more H atoms are optionally replaced by F or Cl, preferably F, Cl, CN or OCH3, very preferably F.

[0232] This indicates that the substituent L of the alkenyl group in compounds of formula I and its subformulas disclosed and claimed in this application is not considered to be within the meaning of the term "polymerizable group" (or group P) as used herein. Preferably, the LC media disclosed and claimed in this application do not contain additives that initiate or enhance the polymerization reaction of the alkenyl L.

[0233] Preferred compounds of formulae I, IA, II, I2, I3, II-1, II-2, I2-1 to I2-6, I3-1 to I3-11 and I4-1 to I4-16, IN and subformulae thereof are selected from the following preferred embodiments, including any combination thereof:

[0234] - a = 1 and b = 0, 1 or 2,

[0235] - a = 2 and b = 0,

[0236] - a1 + a2 = 1 or 2, preferably 1

[0237] - a3 + a4 + a5 = 1 or 2, preferably 1,

[0238] - b1 + b2 = 0, - b1 + b2 = 1 or 2,

[0239] - b3 + b4 + b5 = 0,

[0240] - b3 + b4 + b5 = 1 or 2,

[0241] - c is 1 or 2, preferably 1,

[0242] - the compound contains exactly two polymerizable groups (denoted by the group P),

[0243] - the compound contains exactly three polymerizable groups (denoted by the group P),

[0244] - P is selected from the group consisting of acrylate, methacrylate and oxetane, very preferably acrylate or methacrylate,

[0245] - P is methacrylate,

[0246] - Pg is hydroxyl,

[0247] - all groups Sp are single bonds,

[0248] - at least one of the groups Sp is a single bond and at least one of the groups Sp is different from a single bond,

[0249] - Sp, when different from a single bond, is -(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, p2 and p3 are independently from each other 0, 1, 2 or 3 and the O-atom or the CO-group is attached to the phenyl ring, respectively,

[0250] -Sp is a single bond or denotes -(CH2) p1 - -(CH2) p2 -CH=CH-(CH2) p3 - -(CH2) p1 - -O-CO-(CH2) p1 or -CO-O-(CH2) p1 wherein p1 is 2, 3, 4, 5 or 6, p2 and p3 are independently of each other 0, 1, 2 or 3 and the O-atom or the CO-group is attached to the phenyl ring, respectively,

[0251] - one or more, preferably one group -Sp-P is selected from formulae S1 to S8 and S1a to S3a,

[0252] -A 1 , A 2 independently of each other denote phenylene, naphthalene, phenanthrene or anthracene, preferably 1,4-phenylene, 1,3-phenylene or 2,6-naphthalene, very preferably 1,4-phenylene,

[0253] -Ar denotes benzene, furan or thiophene, very preferably benzene, which is optionally substituted by one or more groups L as defined above and below, and preferably is unsubstituted,

[0254] -L is selected from the group consisting of F, CI, 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 CI, preferably F, CI, CN or OCH3, very preferably F.

[0255] Very preferred compounds of formula I and its subformulae are selected from the following subformulae:

[0256]

[0257]

[0258]

[0259] Further preferred are compounds of formulae I2-1-1 to I 2-4-3, wherein one or both of the methyl acrylate groups are replaced by an acrylate group.

[0260] Preferred compounds of formula IN are selected from those of subformulae IA, 11, 12, 13, 11-1, 11-2, 12-1 to 12-6, 13-1 to 13-11, 14-1 to 14-16 and 12-1-1 to 12-4-2, wherein each group P or each methacrylate group, respectively, is replaced by a group Pg as defined in formula IN, preferably by OH.

[0261] Suitable protected hydroxyl groups Pg for use in compounds of formula IN and its subformulae are known to the person skilled in the art. Preferred protecting groups for hydroxyl groups are alkyl, alkoxyalkyl, acyl, alkylsilyl, arylsilyl and arylmethyl, in particular 2-tetrahydropyranyl, methoxymethyl, methoxyethoxymethyl, acetyl, triisopropylsilyl, tert-butyl-dimethylsilyl or benzyl.

[0262] The term "masked hydroxyl group" is to be understood as meaning any functional group which can be chemically converted into a hydroxyl group. Suitable masked hydroxyl groups Pg are known to the person skilled in the art.

[0263] Compounds of formula IN are suitable as intermediates for the preparation of compounds of formula I and its subformulae.

[0264] The present application further relates to the use of compounds of formula IN as intermediates for the preparation of compounds of formula I and its subformulae.

[0265] Compounds and intermediates of formula I and IN and its subformulae 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 Chemis try], Thieme-Verlag, Stuttgart.

[0266] For example, compounds of formula I can be synthesized by esterification or etherification of intermediates of formula IN using the corresponding acid, acid derivative or halogenated compound containing a polymerizable group P, wherein Pg represents OH.

[0267] For example, acrylates or methacrylates can be prepared by esterification of the corresponding alcohol with an acid derivative, for example (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, the esters can be prepared by esterification of the alcohol with (meth)acrylic acid in the presence of a dehydrating agent, for example according to Steglich with dicyclohexylcarbodiimide (DCC), N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide (EDC) or N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride and DMAP.

[0268] Suitable and preferred synthesis methods of compounds of formula I and IN are shown in the examples.

[0269] The present application further relates to an LC medium comprising one or more compounds of formula I or a subformula thereof. Preferably, the LC medium comprises one or more polymerisable compounds, at least one of which is a compound of formula I or a subformula thereof.

[0270] Further preferably, the LC medium comprises

[0271] - a polymerisable component A) comprising or, preferably, consisting of one or more polymerisable compounds, at least one of which is a compound of formula I,

[0272] - a liquid-crystalline component B), hereinafter also referred to as "LC host mixture", comprising or, preferably, consisting of one or more mesogenic or liquid-crystalline compounds.

[0273] Furthermore, the present application relates to an LC medium or LC display as described above, wherein the polymerisable compounds of formula I or component A) are polymerised.

[0274] Furthermore, the present application relates to the use of compounds of formula I and LC media as described above and below in PSA displays or polymer stabilised SA-VA or HB-SA-FFS displays and to LC displays, in particular PSA displays, comprising one or more compounds of formula I or LC media according to the present application, especially preferably PS-VA, PS-OCB, PS-IPS, PS-FFS, PS-UB-FFS, PS- positive-VA, PS-TN displays, polymer stabilised SA-VA or polymer stabilised SA-HB-FFS displays.

[0275] For the production of PSA or polymer stabilised SA displays, the polymerisable compounds comprised in the LC medium are polymerised or crosslinked (if a compound comprises two or more polymerisable groups) by in situ polymerisation in the LC medium (between the substrates of the LC display), optionally at the same time as a voltage is applied to the electrodes.

[0276] The structure of the display according to the present application corresponds to the usual geometry of PSA displays, as described in the prior art cited at the outset. Preferred are geometries without protrusions, wherein, in addition, the electrodes on the side of the colour filter, in particular, are unstructured and only the electrodes on the TFT side have slots. Particularly suitable and preferred electrode structures for PS-VA displays are described, for example, in US 2006 / 0066793 A1.

[0277] The preferred PSA type LC displays according to the present application comprise:

[0278] - a first substrate comprising a pixel electrode defining a pixel area (which is connected to a switching element arranged in each pixel area and optionally comprises a micro-slit pattern), and optionally a first alignment layer arranged on the pixel electrode,

[0279] - a second substrate comprising a common electrode layer (which can be arranged on the entire portion of the second substrate facing the first substrate), and optionally a second alignment layer,

[0280] - an LC layer arranged between the first and second substrate and comprising an LC medium comprising a polymerizable component A and a liquid crystalline component B as described above and below, wherein the polymerizable component A can also be polymerized.

[0281] 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 chosen such that it imparts a homeotropic (or perpendicular) alignment (i.e. perpendicular to the surface) or a tilted alignment to the LC molecules. Such an alignment layer can for example comprise a polyimide, which can also be rubbed, or can be prepared by a photo-alignment method.

[0282] 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 component of the LC medium is then polymerized, for example by UV light. The polymerization can be carried out in one step or in two or more steps.

[0283] The PSA display can comprise further elements, such as color filters, black matrix, passivation layers, optical retardation layers, transistor elements for addressing individual pixels, etc., all of which are well known to the person skilled in the art and can be used without inventive skill.

[0284] The person skilled in the art can design the electrode structure depending on the individual display type. For example, for a PS-VA display, a multi-domain orientation of the LC molecules can be induced by providing electrodes with slits and / or bumps or protrusions in order to generate two, four or more differently tilted alignment directions.

[0285] After polymerization, the polymerizable compound forms a cross-linked polymer, which leads to a certain tilt angle of the LC molecules in the LC medium. Without wishing to be bound to 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 out of the LC medium and form a polymer layer on the substrate or electrode, or on an alignment layer provided thereon. Microscopy data (such as SEM and AFM) have confirmed that at least a portion of the polymer formed accumulates on the LC / substrate interface.

[0286] The polymerization can be carried out in one step. It is also possible to first carry out the polymerization in a first step, optionally at the same time applying a voltage, in order to produce a tilt angle, and subsequently to polymerize or crosslink the compounds which have not reacted in the first step in a second polymerization step without the application of a voltage ("final curing").

[0287] Suitable and preferred polymerization methods are, for example, thermal or photopolymerization, preferably photopolymerization, in particular UV-induced photopolymerization, which can be achieved by exposing the polymerizable compounds to UV radiation.

[0288] Optionally, one or more polymerization initiators are added to the LC medium. Suitable conditions for the polymerization and suitable types and amounts of initiators are known to the person skilled in the art and are described in the literature. Suitable for free-radical polymerization are, for example, the commercially available photoinitiators or Irgacure® (Ciba AG). If polymerization initiators are used, their proportion is preferably 0.001 to 5% by weight, particularly preferably 0.001 to 1% by weight.

[0289] The polymerizable compounds according to the application are also suitable for polymerization without initiators, which is accompanied by considerable advantages, for example, low material costs and, in particular, less contamination of the LC medium by possible residual amounts of initiators or degradation products thereof. The polymerization can thus also be carried out without the addition of initiators. In a preferred embodiment, the LC medium thus comprises no polymerization initiators.

[0290] The LC medium can also comprise one or more stabilizers in order to prevent spontaneous polymerization of the RMs which is undesirable, 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, the stabilizers from the Irgastab® series (Ciba AG), for example Irgastab® 16, Irgastab® 17 or Irgastab® 25. If stabilizers are used, their proportion is preferably 10-50,000 ppm, particularly preferably 50-5,000 ppm, based on the total amount of RMs or polymerizable components (component A). 1076. If stabilizers are used, their proportion is preferably 10-50,000 ppm, particularly preferably 50-5,000 ppm, based on the total amount of RMs or polymerizable components (component A).

[0291] In a preferred embodiment, the liquid-crystalline medium contains one or more chiral dopants preferably in a concentration of 0.01% to 1% by weight, very preferably 0.05% to 0.5% by weight. The chiral dopant is preferably selected from the group consisting of the compounds from Table B below, very preferably from the group consisting of R- or S-1011, R- or S-2011, R- or S-3011, R- or S-4011 and R- or S-5011.

[0292] In another preferred embodiment, the liquid-crystalline medium contains one or more racemates of chiral dopants, which are preferably selected from the chiral dopants mentioned in the last paragraph.

[0293] In another preferred embodiment of the present application, the liquid-crystalline medium contains one or more further stabilizers, preferably selected from the group consisting of formulae

[0294]

[0295]

[0296] wherein each group independently of each other and on each occurrence identically or differently has the following meaning:

[0297] R a-d is a linear or branched alkyl group having 1 to 10, preferably 1 to 6, very preferably 1 to 4 C atoms, most preferably is methyl,

[0298] X S is H, CH3, OH or O ● ,

[0299] A S is a linear, branched or cyclic alkylene group having 1 to 20 C atoms, which is optionally substituted,

[0300] n is an integer from 1 to 6, preferably is 3.

[0301] Preferred stabilizers of formula S3 are selected from formula S3A

[0302]

[0303] wherein n2 is an integer from 1 to 12, and wherein one or more H atoms in the group (CH2) n2 are optionally replaced by methyl, ethyl, propyl, butyl, pentyl or hexyl.

[0304] Very preferred stabilizers are selected from the group consisting of formulae

[0305]

[0306]

[0307]

[0308] In a preferred embodiment, the liquid-crystalline medium comprises one or more stabilizers selected from the group consisting of formula S1-1, formula S2-1, formula S3-1, formula S3-1 and formula S3-3.

[0309] In a preferred embodiment, the liquid crystalline medium comprises one or more stabilizers selected from Table C below.

[0310] Preferably, the proportion of stabilizers in the liquid crystalline medium, such as those of the formulae S1 to S3, is 10 to 500 ppm, very preferably 20 to 100 ppm.

[0311] In another preferred embodiment, the LC medium of the present application contains a self-alignment (SA) additive, preferably in a concentration of 0.1 to 2.5%.

[0312] In another preferred embodiment, the LC medium of the present application contains a self-alignment (SA) additive, preferably in a concentration of 0.1 to 2.5%. The LC medium of this preferred embodiment is especially suitable for SA-VA and SA-HB-FFS displays.

[0313] In a preferred embodiment, the SA-VA or SA-HB-FFS display of the present application does not contain a polyimide alignment layer. In another preferred embodiment, the SA-VA or SA-HB-FFS display of the preferred embodiment contains a polyimide alignment layer.

[0314] Preferred SA additives for this preferred embodiment are selected from compounds comprising a mesogenic group and a linear or branched alkyl side chain, which is terminated by one or more polar anchoring groups selected from a hydroxyl, a carboxyl, an amine or a thiol group.

[0315] Further preferred SA additives contain one or more polymerizable groups, which are optionally connected to the mesogenic group via a spacer group. These polymerizable SA additives can be polymerized in the LC medium under similar conditions as the RMs applied in the PSA process.

[0316] Suitable SA additives to induce homeotropic alignment, especially for use in SA-VA mode displays, are disclosed, for example, in US 2013 / 0182202 A1, US 2014 / 0838581 A1, US 2015 / 0166890 A1 and US 2015 / 0252265 A1.

[0317] In another preferred embodiment, the LC medium of the present application comprises one or more SA additives selected from formula II

[0318] MES-R a II

[0319] wherein each of the radicals, independently of each other and on each occurrence identically or differently, has the following meanings:

[0320] MES is a rod-like mesogenic group comprising two or more rings, which are directly or indirectly connected to each other or which are fused to each other, which is optionally substituted and which mesogenic group is optionally further substituted by one or more polymerisable groups, which are attached to the MES directly or via a spacer, and

[0321] R a is a polar anchoring group at the terminal position of the rod-like mesogenic group MES, which comprises at least one carbon atom and at least one group selected from -OH, -SH, -COOH, -CHO or a primary or secondary amine function, preferably one or two OH groups, and which optionally contains one or two polymerisable groups P,

[0322] P is one of the meanings given in formula I or one of the preferred meanings given above and below.

[0323] The self-orienting additive containing polymerisable groups can be polymerised in the LC medium under similar conditions as the RMs applied in the PSA process.

[0324] Preferably, in the self-orienting additive of formula II, the group MES contains two or more rings selected from aryl, alicyclyl and heterocyclyl as defined above, including the preferred meanings thereof. Most preferably the rings are 1,4-phenylene, which can be substituted by L 12 and P-Sp-, or 1,4-cyclohexylene.

[0325] In formula II, the group MES is preferably a group selected from the following structures, which can be mono- or poly-substituted by any of the substituents L 12 and P-Sp:

[0326]

[0327]

[0328] wherein

[0329] L 12 in each case independently of one another F, Cl, Br, I, -CN, -NO2, -NCO, -NCS, -OCN, -SCN, -C(=O)N(R 0 )2, -C(=O)R 0 , an optionally substituted silyl group, an optionally substituted aryl or cycloalkyl group having 3 to 20 C atoms, or a straight-chain or branched alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy group having up to 25 C atoms, where in addition one or more H atoms can each be replaced by F or Cl,

[0330] P denotes a polymerisable group, and

[0331] Sp represents a spacer group or a single bond,

[0332] and the dotted line indicates the point of attachment of the polar anchoring group R a .

[0333] Preferably, the self-alignment additive for vertical alignment is selected to have the formula IIa

[0334] R 21 -[A 22 -Z 22 ] m2 -A 22 -R a IIa

[0335] wherein

[0336] A 21 ,A 22 each, independently of one another, denotes aryl, heteroaryl, alicyclyl or heterocyclyl, which can also contain fused rings, and which can also be mono- or polysubstituted by groups L 12 or -Sp-P,

[0337] L 12 in each case, independently of one another, F, Cl, Br, I, -CN, -NO2, -NCO, -NCS, -OCN, -SCN, -C(=O)N(R 0 )2, -C(=O)R 0 , optionally substituted silyl, optionally substituted aryl or cycloalkyl having 3 to 20 C atoms, or straight-chain or branched alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy having up to 25 C atoms, where, in addition, one or more H atoms can each be replaced by F or Cl,

[0338] P represents a polymerisable group,

[0339] Sp represents a spacer group or a single bond,

[0340] Z 22 in each case, independently of one another, a single bond, -O-, -S-, -CO-, -CO-O-, -OCO-, -O-CO-O-, -OCH2-, -CH2O-, -SCH2-, -CH2S-, -CF2O-, -OCF2-, -CF2S-, -SCF2-, -(CH2) n1 -, n1 -(CF2) 0 -, 00 n1 ​-CH2CH(-Sp-P)- or -CH(-Sp-P)CH(-Sp-P)-,

[0341] n1 denotes 1, 2, 3 or 4,

[0342] m2 denotes 1, 2, 3, 4, 5 or 6,

[0343] R 0 in each case independently of one another H or alkyl having 1 to 12 C atoms,

[0344] R 00 in each case independently of one another H or alkyl having 1 to 12 C atoms,

[0345] R 21 independently of one another H, halogen, straight-chain, branched or cyclic alkyl having 1 to 25 C atoms, where, in addition, one or more non-adjacent CH2groups can each be replaced, in each case independently of one another, by -O-, -S-, -CO-, -CO-O-, -O-CO- or -O-CO-O-, and where, in addition, one or more H atoms can each be replaced by F or Cl,

[0346] or the group P-Sp-, and

[0347] R a as defined above, preferably denotes a polar anchoring group, which is further defined as follows: a group having at least one group selected from -OH, -NH2, NHR 22 , C(O)OH and -CHO, where R 22 denotes alkyl having 1 to 12 C atoms.

[0348] In a further preferred embodiment, the LC medium or the polymer stabilised SA-VA display of the present application contains one or more self-alignment additives selected from Table E below.

[0349] The anchoring group R a is more preferably defined as:

[0350] R a is an anchoring group of the following formula:

[0351]

[0352] wherein

[0353] p denotes 1 or 2,

[0354] q denotes 2 or 3,

[0355] B denotes a substituted or unsubstituted ring system or a fused ring system, preferably a ring system selected from the group consisting of benzene, pyridine, cyclohexane, dioxane or tetrahydropyran,

[0356] Y, on each occurrence, identically or differently, denotes -0-, -S-, -C(O)-, -C(0)0-, -OC(O)-, -NR 11 or a single bond,

[0357] o denotes 0 or 1,

[0358] X 1 H, alkyl, fluoroalkyl, OH, NH2, NHR 22 , NR 22 2, OR 22 , C(0)OH or -CHO, wherein at least one group X 1 denotes a group selected from the group consisting of -OH, -NH2, NHR 22 , C(0)OH and -CHO,

[0359] R 22 denotes an alkyl group having 1 to 12 C atoms,

[0360] Sp a , Sp c , Sp d each, independently of one another, denotes a spacer group or a single bond, and

[0361] Sp b denotes a trivalent or tetravalent group, preferably CH, N or C.

[0362] Formula II and Formula I la optionally include polymerizable compounds. Within the present application, a "medium comprising a compound of Formula II / I la" means both a medium comprising a compound of Formula II / I la and, or a medium comprising the compound in its polymerized form.

[0363] In case one or more compounds of Formula II are substituted by one or more polymerizable groups (-Sp-P), the LC medium of the present application comprises

[0364] - a polymerizable component A) comprising, preferably consisting of, polymerizable compounds, at least one of which is a compound of Formula I, and at least one of which has Formula II,

[0365] - a liquid-crystalline component B), hereinafter also referred to as "LC host mixture", comprising, preferably consisting of, one or more mesogenic or liquid-crystalline compounds.

[0366] In the compounds of Formula IIa and its subformulae, Z 22preferably denotes a single bond, -C2H4-, -CF2O- or -CH2O-. In a particularly preferred embodiment, Z 22 denotes a single bond.

[0367] In the compounds of the formula IIa, the group L 12 independently in each case preferably denotes F or alkyl, preferably CH3, C2H5or C3H7.

[0368] The compounds of the formula IIa are preferably explained by the following subformulae II-A to II-D

[0369]

[0370] in which R 21 , R a , A 22 , Z 22 , Sp, P and L 12 have the meanings as defined above for the formula IIa,

[0371] m2 is independently 1, 2 or 3, and

[0372] r1 is independently 0, 1, 2, 3 or 4, preferably 0, 1 or 2.

[0373] In the compounds of the formulae II-A to II-D, L 12 preferably denotes F or alkyl, preferably CH3, C2H5or C3H7.

[0374] In a preferred embodiment, r1 denotes 0.

[0375] The polymerisable group P of the formula II, of the formula IIa, of the formulae II-A to II-D is preferably a methacrylate, an acrylate or another substituted acrylate, most preferably a methacrylate.

[0376] In the above and below formulae IIa or II-A to II-D and their subformulae, Z 22 preferably independently denotes a single bond or -CH2CH2-, and very particularly a single bond.

[0377] R a preferably denotes:

[0378]

[0379] in which

[0380] p is 1, 2, 3, 4, 5 or 6,

[0381] x is 1 or 0, preferably 1, and

[0382] R 23H, methyl, ethyl, n-propyl, i-propyl, n-butyl, t-butyl, n-pentyl or -CH2CH2-t-butyl,

[0383] R a very preferably -O(CH2)2-OH, -O(CH2)3-OH,

[0384]

[0385] In formula IIa and the subformulae of formula IIa, R 21 preferably denotes a straight-chain or branched alkyl group having 1 to 8 C atoms, preferably a straight-chain alkyl group. In the compounds of formula IIa or formulae II-A to II-D, R 1 more preferably denotes CH3, C2H5, n-C3H7, n-C4H9, n-C5H 11 , n-C6H 13 or CH2CH(C2H5)C4H9. Furthermore, R 21 may denote alkenyloxy, in particular OCH2CH=CH2, OCH2CH=CHCH3, OCH2CH=CHC2H5or alkoxy, in particular OC2H5, OC3H7, OC4H9, OC5H 11 and OC6H 13 . Particularly preferred is R 21 denotes a straight-chain alkyl residue, preferably C5H 11 .

[0386] In a preferred embodiment of the present application, the LC medium comprises a compound of formula II, which is polymerisable.

[0387] In another preferred embodiment, the LC medium or the polymer stabilised SA-VA or SA-FFS display of the present application contains one or more self-alignment additives selected from Table E below.

[0388] In another preferred embodiment, the LC medium of the present application contains one or more SA additives, preferably selected from formula II or a subformula thereof or from Table E, in a concentration of 0.1 to 5 %, very preferably of 0.2 to 3 %. Most preferred is 0.2 to 1.5 %.

[0389] In particular, the polymerisable compounds of formula I show good UV absorption in a method of preparing a PSA display and are therefore especially suitable for this method, which comprises one or more of the following features:

[0390] - the polymerisable medium is exposed to UV light in the display in a 2-step process, comprising a first UV exposure step ("UV1 step") with application of a voltage to generate a tilt angle, and a second UV exposure step ("UV2 step") without application of a voltage to complete polymerisation,

[0391] - the polymerisable medium is exposed to UV light generated by a UV-LED lamp in the display, preferably at least in the UV2 step, more preferably in the UV1 and UV2 steps.

[0392] - the polymerisable medium is exposed to UV light generated by a UV lamp in the display, the radiation spectrum of which is shifted to longer wavelengths, preferably > 340 nm, more preferably 350 nm to < 370 nm, very preferably 355 nm to 368 nm, to avoid short UV light exposure in the PS-VA process.

[0393] Both the use of lower intensity and the UV shift to longer wavelengths protect the organic layers from damage that can be caused by UV light.

[0394] Preferred embodiments of the present application relate to a process for the preparation of a PSA display as described above and below, comprising one or more of the following features:

[0395] - the polymerisable LC medium is irradiated with UV light in a 2-step process, comprising a first UV exposure step ("UV1 step") with applied voltage to create a tilt angle, and a second UV exposure step ("UV2 step") without applied voltage to complete polymerisation,

[0396] - the polymerisable LC medium is irradiated with UV light generated by a UV lamp, preferably in the UV2 step and optionally also in the UV1 step, which UV lamp has an intensity of 0.5 mW / cm 2 to 10 mW / cm 2 in the wavelength range of 300 nm to 380 nm,

[0397] - the polymerisable LC medium is irradiated with UV light having a wavelength of > 340 nm and < 420 nm, preferably > 350 nm, preferably in the range of 340 nm to 400 nm, more preferably in the range of 350 nm to 390 nm, very preferably in the range of 360 nm to 380 nm, most preferably in the range of 360 nm to 368 nm,

[0398] - the polymerisable LC medium is irradiated with UV light while a voltage is applied to the electrodes of the display,

[0399] - the irradiation with UV light is carried out using a UV-LED lamp.

[0400] This preferred method can be implemented, for example, by using a desired UV lamp or by using a bandpass filter and / or cutoff filter that substantially transmits UV light with the desired wavelength and substantially blocks light with the undesired wavelength. For instance, when UV irradiation with a wavelength λ of 300 nm to 400 nm is desired, a broadband pass filter that substantially transmits wavelengths 300 nm < λ < 400 nm can be used to implement UV exposure. When UV irradiation with a wavelength λ exceeding 340 nm is desired, a cutoff filter that substantially transmits wavelengths λ > 340 nm can be used to implement UV irradiation.

[0401] This preferred method enables the manufacture of displays using longer UV wavelengths, thereby reducing or even avoiding the dangerous and damaging effects of short UV light components.

[0402] "Substantially transmits" means that the filter transmits a large portion, preferably at least 50%, of the intensity of the incident light at the desired wavelength. "Substantially blocks" means that the filter does not transmit a large portion, preferably at least 50%, of the intensity of the incident light at the undesired wavelength. "Desired (undesired) wavelength" in the case of, for example, a bandpass filter, means a wavelength within (outside) a given range of λ, and in the case of a cutoff filter, means a wavelength higher than (lower than) a given value of λ.

[0403] Preferably, UV-LED lamps are used to implement UV irradiation.

[0404] Using UV-LED lamps with only a narrow emission peak in the PSA process offers several advantages, such as more efficient light energy transfer to polymerizable compounds in the LC medium, depending on the selection of suitable polymerizable compounds that exhibit absorption at the emission wavelength of the LED lamp. This allows for reduced UV intensity and / or UV irradiation time, thereby enabling reduced cycle time and saving energy and production costs. Another advantage is that the narrow emission spectrum of the lamp allows for easier selection of the appropriate wavelength for photopolymerization.

[0405] Very preferably, the UV light source is a UV-LED lamp that emits wavelengths in the range of 340nm to 400nm, more preferably in the range of 350nm to 390nm, very preferably in the range of 360nm to 380nm, and most preferably in the range of 360nm to 368nm. A UV-LED lamp that emits UV light with a wavelength of 365nm is particularly preferred.

[0406] Depending on the production method and conditions, the UV radiation energy is preferably 6J to 100J.

[0407] The LC medium according to the present application preferably consists indeed essentially of the polymerisable component A), or one or more polymerisable compounds of formula I as described above and below, and the LC component B) or LC host mixture. However, the LC medium can additionally comprise one or more further components or additives, preferably selected from the list comprising, but not limited to, co-monomers, chiral dopants, polymerisation initiators, inhibitors, stabilizers, surfactants, wetting agents, lubricants, dispersants, hydrophobing agents, adhesion agents, flow improvers, antifoams, degassing agents, diluents, reactive diluents, auxiliaries, colourants, dyes, pigments and nanoparticles.

[0408] Particularly preferred are LC media comprising one, two or three polymerisable compounds of formula I.

[0409] Further preferred are LC media wherein the polymerisable component A) comprises only polymerisable compounds of formula I.

[0410] Further preferred are LC media wherein the liquid crystalline component B) or LC host mixture has a nematic LC phase and preferably no chiral liquid crystalline phase.

[0411] The LC component B) or LC host mixture is preferably a nematic LC mixture.

[0412] Further preferred are achiral compounds of formula I and LC media wherein the compounds of components A and / or B are selected only from the group consisting of achiral compounds.

[0413] Preferably, especially when used in SA-VA displays, the proportion of the polymerisable component A) in the LC medium is > 0 to < 5 %, very preferably > 0 to < 3 %, more preferably 0.01 to 2.0. In another preferred embodiment, especially when used in PSA displays, the proportion of the polymerisable component A) in the LC medium is 0.01 to 1.0 %, most preferably 0.01 to 0.5 %.

[0414] Preferably, especially when used in SA-VA displays, the proportion of the compounds of formula I in the LC medium is > 0 to < 5 %, very preferably > 0 to < 3 %, more preferably 0.01 to 2.0. In another preferred embodiment, especially when used in PSA displays, the proportion of the compounds of formula I in the LC medium is 0.01 to 1.0 %, most preferably 0.01 to 0.5 %.

[0415] Preferably, the proportion of the LC component B) in the LC medium is 95 to < 100 %, very preferably 96.5 to < 100 %, most preferably 98 to < 100 %. In another preferred embodiment, the proportion of the LC component B) in the LC medium is 99 to < 100 %.

[0416] In a preferred embodiment, the polymerizable compounds of the polymerizable component B) are selected from formula I only.

[0417] In another preferred embodiment, the polymerizable component B) comprises one or more further polymerizable compounds ("comonomers") in addition to the compounds of formula I, which are preferably selected from RM.

[0418] Suitable and preferred mesogenic comonomers are selected from the following formulae:

[0419]

[0420]

[0421]

[0422]

[0423] wherein each of the radicals has the following meaning:

[0424] P 1 , P 2 and P 3 each, independently of one another, denotes an acrylate group or a methacrylate group,

[0425] Sp 1 , Sp 2 and Sp 3 each, independently of one another, denotes a single bond or a spacer group (with one of the meanings described above and below for Sp), and especially preferably denotes -(CH2) p1 -, -(CH2) p1 -O-, -(CH2) p1 -CO-O-, -(CH2) p1 -O-CO- or -(CH2) p1 -O-CO-O-, wherein p1 is an integer from 1 to 12, and further wherein one or more of the radicals P 1 -Sp 1 -, P 2 -Sp 2 - and P 3 -Sp 3 - can denote R aa , with the proviso that at least one of the radicals P 1 -Sp 1 -, P 2 -Sp 2 - and P 3 -Sp 3 - is different from R aa ,

[0426] R aarepresents H, F, CI, CN or straight-chain or branched alkyl with 1 to 25 C atoms, wherein, in addition, one or more non-adjacent CH2groups can each be independently of one another replaced by -C(R 0 ) = C(R 00 )-, -C≡C-, -N(R 0 )-, -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O- in such a way that O and / or S atoms are not linked directly to one another, and in which, in addition, one or more H atoms can be replaced by F, CI, CN or P 1 -Sp 1 - represents, in particular, straight-chain or branched, optionally mono- or polyfluorinated alkyl, alkoxy, alkenyl, alkynyl, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy with 1 to 12 C atoms (wherein alkenyl and alkynyl have at least two C atoms and branched groups have at least three C atoms),

[0427] R 0 , R 00 each, independently of one another and on each occurrence identically or differently, denotes H or alkyl with 1 to 12 C atoms,

[0428] R y and R z each, independently of one another, denotes H, F, CH3or CF3,

[0429] X 1 , X 2 and X 3 each, independently of one another, denotes -CO-O-, -O-CO- or a single bond,

[0430] Z 1 denotes -O-, -CO-, -C(R y R z )- or -CF2CF2-,

[0431] Z 2 and Z 3 each, independently of one another, denotes -CO-O-, -O-CO-, -CH2O-, -OCH2-, -CF2O-, -OCF2- or -(CH2) n - with n being 2, 3 or 4,

[0432] L each occurrence, identically or differently, denotes F, CI, CN or straight-chain or branched, optionally mono- or polyfluorinated alkyl, alkoxy, alkenyl, alkynyl, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy with 1 to 12 C atoms, preferably F,

[0433] L' and L" each, independently of one another, denote H, F or CI,

[0434] k denotes 0 or 1,

[0435] r denotes 0, 1, 2, 3 or 4,

[0436] s denotes 0, 1, 2 or 3,

[0437] t denotes 0, 1 or 2,

[0438] x denotes 0 or 1.

[0439] Especially preferred are compounds of formulae M2, M13, M17, M22, M23, M24, M30, M31 and M32.

[0440] More preferred are trireactive compounds M15 to M30, in particular M17, M18, M19, M22, M23, M24, M25, M26, M30, M31 and M32.

[0441] In another preferred embodiment, in addition to the compound of formula I, the polymerisable component B) comprises one or more co-monomers selected from formula M2 and formula M13, wherein at least one r is 1 and L is an alkenyl group having 2 to 7 C atoms.

[0442] In another preferred embodiment, in addition to the compound of formula I, the polymerisable component B) comprises one or more co-monomers selected from the following table D.

[0443] In the compounds of formulae M1 to M32, the group

[0444] is preferably

[0445]

[0446] wherein L has on each occurrence, identically or differently, one of the meanings given above or below and is preferably F, CI, 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, CI, CN, CH3, C2H5, OCH3, COCH3, OCF3 or P-Sp-, more preferably F, CI, CH3, OCH3, COCH3 or OCF3, in particular F or CH3.

[0447] In addition to the polymerisable compounds described above, the LC medium used according to the application comprises an LC mixture ("host mixture") which comprises one or more, preferably two or more than two, LC compounds selected from non-polymerisable low-molecular-weight compounds. These LC compounds are selected such that they are stable and / or unreactive towards the polymerisation reaction under the conditions applied for the polymerisation of the polymerisable compounds.

[0448] In principle, any LC mixture suitable for conventional displays is suitable as host mixture. Suitable LC mixtures are known to the person skilled in the art and are described in the literature, for example the mixtures in VA displays in EP 1 378 557 A1 and the mixtures for OCB displays in EP 1 306 418 A1 and DE 102 24 046 A1.

[0449] The polymerisable compounds of formula I are particularly suitable for LC host mixtures which comprise one or more mesogenic or LC compounds comprising an alkenyl group (in the following also referred to as "alkenyl compounds"), wherein the alkenyl group is stable towards the polymerisation reaction under the conditions used for the polymerisation of the compounds of formula I and for the polymerisation of other polymerisable compounds comprised in the LC medium. Compared to the RMs known from the prior art, the compounds of formula I exhibit improved properties in such LC host mixtures, such as solubility, reactivity or ability to generate tilt angles.

[0450] Thus, in addition to the polymerisable compounds of formula I, the LC medium according to the application comprises one or more mesogenic or liquid-crystalline compounds comprising an alkenyl group ("alkenyl compounds"), wherein this alkenyl group is preferably stable towards the polymerisation reaction under the conditions used for the polymerisation of the polymerisable compounds of formula I or for the polymerisation of other polymerisable compounds comprised in the LC medium.

[0451] The alkenyl group in the alkenyl compounds is preferably selected from linear, branched or cyclic alkenyl groups which in particular have 2 to 25 C atoms, particularly preferably 2 to 12 C atoms, further in which one or more non-adjacent CH2 groups can be replaced by -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O- in such a way that O and / or S atoms are not linked directly to one another, and in which one or more H atoms can be replaced by F and / or Cl.

[0452] Preferred alkenyl groups are linear alkenyl groups having 2 to 7 C atoms and cyclohexenyl groups, in particular ethenyl, propenyl, butenyl, pentenyl, hexenyl, heptenyl, 1,4-cyclohex-1 -en-1 -yl and 1,4-cyclohex-3-en-1 -yl.

[0453] The concentration of the compounds containing alkenyl groups in the LC host mixture (i.e. without any polymerisable compounds) is preferably 5% to 100%, very preferably 20% to 60%.

[0454] Especially preferred are LC mixtures which contain 1 to 5, preferably 1, 2 or 3 compounds having alkenyl groups.

[0455] Preferred mesogens and LC compounds containing alkenyl groups are also shown in the preferred embodiments described below.

[0456] In addition to the polymerisable component A) as described above, the LC medium according to the application comprises an LC component B) or LC host mixture which comprises one or more, preferably two or more than two LC compounds selected from non-polymerisable low molecular weight compounds. These LC compounds are selected such that they are stable and / or unreactive towards the polymerisation reaction under the conditions applied for the polymerisation of the polymerisable compounds.

[0457] In a first preferred embodiment, the LC medium contains an LC component B) or LC host mixture based on compounds having negative dielectric anisotropy. This LC medium is especially suitable for PS-VA, SA-VA and PS-UB-FFS displays. A particularly preferred embodiment of this LC medium is described below.

[0458] Preferably, according to the first preferred embodiment, the LC medium contains one or more compounds selected from the group consisting of compounds of formulae IIA, IIB, IIC and IID

[0459]

[0460] wherein

[0461] R 2A and R 2B each, independently of one another, denotes H, alkyl or alkenyl having up to 15 C atoms which is unsubstituted, mono- or di-substituted by CN or CF3 or mono-substituted by halogen, and furthermore in which one or more CH2 groups are each replaced, independently of one another, by -O-, -S-, -C≡C-, -CF2O-, -OCF2-, -OC- O- or -O-CO-,

[0462] L 1 to L 4 each, independently of one another, denotes F, Cl, CF3 or CHF2,

[0463] Y denotes H, F, Cl, CF3, CHF2 or CH3, preferably H or CH3, especially preferably H,

[0464] Z 2 , Z 2B and Z 2Deach, independently of one another, denotes a single bond, -CH2CH2-, -CH=CH-, -CF2O-, -OCF2-, -CH2O-, -OCH2-, -COO-, -OCO-, -C2F4-, -CF=CF-, -CH=CHCH2O-, p denotes 0, 1 or 2, and

[0465] q denotes, on each occurrence, identically or differently, 0 or 1.

[0466] Preferred compounds of the formulae IIA, IIB, IIC and IID are those in which R 2B denotes alkyl or alkoxy having up to 15 C atoms, and very preferably (O)C v H 2v+1 in which (O) is an oxygen atom or a single bond and v is 1, 2, 3, 4, 5 or 6.

[0467] Further preferred compounds of the formulae IIA, IIB, IIC and IID are those in which R 2A or R 2B denotes or contains a cycloalkyl or cycloalkoxy group, which is preferably selected from the group consisting of: in which S 1 is C 1-5 -alkylene or C 2-5 -alkenylene and S 2 is H, C 1-7 -alkyl or C 2-7 -alkenyl, and very preferably is selected from the group consisting of:

[0468] Further preferred compounds of the formulae IIA, IIB, IIC and IID are indicated below:

[0469]

[0470]

[0471]

[0472]

[0473]

[0474]

[0475]

[0476]

[0477]

[0478]

[0479] wherein the parameter a denotes 1 or 2, alkyl and alkyl* each, independently of one another, denote a straight-chain alkyl radical having 1 to 6 C atoms, and alkenyl denotes a straight-chain alkenyl radical having 2 to 6 C atoms, and (O) denotes an oxygen atom or a single bond. Alkenyl preferably denotes 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-.

[0480] Especially preferred LC media according to the present application comprise one or more compounds of formulae II A-2, II A-8, II A-10, II A-16, II-18, II A-40, II A-41, II A-42, II A-43, I IB-2, I IB-10, I IB-16, I IC-1 and IID-4.

[0481] The proportion of compounds of formulae II A and / or II B in the overall mixture is preferably at least 20% by weight.

[0482] In a further preferred embodiment, the LC medium according to the first preferred embodiment comprises one or more compounds of formula III

[0483]

[0484] wherein

[0485] R 11 and R 12 each, independently of one another, denote H, an alkyl or alkoxy radical having 1 to 15 C atoms, wherein, furthermore, one or more CH2groups in the radical can each, independently of one another, be replaced by -C≡C-, -CF2O-, -OCF2-, -CH=CH-, -O-, -CO-O-, or -O-CO-, and wherein, furthermore, one or more H atoms can be replaced by halogen,

[0486] A 3 denote, independently of one another in each occurrence

[0487] a) 1,4-cyclohexenylene or 1,4-cyclohexylene, wherein one or two non-adjacent CH2groups can be replaced by -O- or -S-,

[0488] b) 1,4-phenylene, wherein one or two CH groups can be replaced by N, or

[0489] c) a radical selected from the group consisting of spiro[3.3]heptane-2,6-diyl, 1,4- bicyclo[2.2.2]ylidene, 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,

[0490] wherein the radicals a), b) and c) can be mono- or polysubstituted by halogen atoms,

[0491] n denotes 0, 1 or 2, preferably 0 or 1,

[0492] Z 1 independently of one another in each occurrence denote -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

[0493] L 11 and L 12 each, independently of one another, denote F, CI, CF3or CHF2, preferably H or F, most preferably F, and W denotes O or S.

[0494] Preferably, the LC medium comprises one or more compounds of formula III selected from formulae III-1 and III-2

[0495]

[0496] wherein the occurring radicals have the same meaning as given under formula III, and preferably

[0497] R 11 and R 12 each, independently of one another, is alkyl, alkenyl or alkoxy having up to 15 C atoms, more preferably one or two of them denote alkoxy and

[0498] L 11 and L 12 each preferably denote F.

[0499] In preferred embodiments, the LC medium comprises one or more compounds of formula III-1 selected from formulae III-1 -1 to III-1 -11, preferably of formula III-1 -6,

[0500]

[0501]

[0502] wherein alkyl and alkyl* each, independently of one another, denote a straight-chain alkyl group having 1 to 6 C atoms, alkenyl and alkenyl* each, independently of one another, denote a straight-chain alkenyl group having 2 to 6 C atoms, alkoxy and alkoxy* each, independently of one another, denote a straight-chain alkoxy group having 1 to 6 C atoms, and L 11 and L 12 each, independently of one another, denote F or CI, preferably both are F.

[0503] In a further preferred embodiment, the LC medium comprises one or more compounds of formula III-2 selected from formulae III-2-1 to III-2-11, preferably of formula III-2-6,

[0504]

[0505]

[0506] wherein alkyl and alkyl* each, independently of one another, denote a straight-chain alkyl group having 1 to 6 C atoms, alkenyl and alkenyl* each, independently of one another, denote a straight-chain alkenyl group having 2 to 6 C atoms, alkoxy and alkoxy* each, independently of one another, denote a straight-chain alkoxy group having 1 to 6 C atoms, and L 1 and L 2 each, independently of one another, denote F or CI, preferably both are F.

[0507] In a further preferred embodiment, the LC medium comprises one or more compounds of formula IIIA-1 and / or IIIA-2

[0508]

[0509] wherein L 11 and L 12 have the same meaning as given under formula III, (O) denotes O or a single bond,

[0510] R IIIA denote alkyl or alkenyl groups having up to 7 C atoms or the group Cy-C m H 2m+1 -,

[0511] m and n are the same or different 0, 1, 2, 3, 4, 5 or 6, preferably 1, 2 or 3, very preferably 1, and

[0512] Cy represents a cycloaliphatic group having 3, 4, or 5 ring atoms, optionally substituted with an alkyl or alkenyl group having a maximum of 3 carbon atoms, or a halogen or CN group, and preferably represents cyclopropyl, cyclobutyl, or cyclopentyl.

[0513] As a substitute for or in addition to the compound of formula III, preferably in addition to the compound of formula III, the LC medium also contains compounds of formula IIIA-1 and / or IIIA-2.

[0514] The most preferred compounds of formula IIIA-1 and IIIA-2 are as follows:

[0515]

[0516]

[0517] Here, alkoxy represents a straight-chain alkoxy group having 1 to 6 carbon atoms.

[0518] In another preferred embodiment, the LC medium comprises one or more compounds of formula III-3.

[0519]

[0520] in

[0521] R 11 R 12 The same or different representations of H, alkyl or alkoxy groups having 1 to 15 C atoms, wherein one or more CH2 groups of these groups are optionally independently connected to each other via -C≡C-, -CF2O-, -OCF2-, -CH=CH-, in such a manner that the O atoms are not directly connected to each other. -O-, -CO-O-, or -O-CO- substitutions, and in addition, one or more of the H atoms may be substituted with halogens.

[0522] Compounds of formula III-3 are preferably selected from the group consisting of compounds of formulas III-3-1 to III-3-10:

[0523]

[0524]

[0525] Where R 12 The alkyl group having 1 to 7 carbon atoms is preferred, ethyl, n-propyl or n-butyl, or alternatively cyclopropylmethyl, cyclobutylmethyl or cyclopentylmethyl.

[0526] In another preferred embodiment, the LC medium comprises one or more compounds of formula III-4 to III-6, preferably formula III-5.

[0527]

[0528] wherein the parameters have the meanings given above, R 11 preferably denotes a linear alkyl group and R 12 preferably denotes an alkoxy group, each having 1 to 7 C atoms.

[0529] In another preferred embodiment, the LC medium comprises one or more compounds of formula I selected from the group of compounds of formulae III-7 to III-9, preferably of formula III-8,

[0530]

[0531] wherein the parameters have the meanings given above, R 11 preferably denotes a linear alkyl group and R 12 preferably denotes an alkoxy group, each having 1 to 7 C atoms.

[0532] In another preferred embodiment, the LC medium according to the first preferred embodiment comprises one or more compounds of formula IV,

[0533]

[0534] wherein

[0535] R 41 denotes an unsubstituted alkyl group having 1 to 7 C atoms or an unsubstituted alkenyl group having 2 to 7 C atoms, preferably n-alkyl, especially preferably having 2, 3, 4 or 5 C atoms, and

[0536] R 42 denotes an unsubstituted alkyl group having 1 to 7 C atoms or an unsubstituted alkoxy group having 1 to 6 C atoms, both preferably having 2 to 5 C atoms; an unsubstituted alkenyl group having 2 to 7 C atoms, preferably having 2, 3 or 4 C atoms; more preferably vinyl or 1-propenyl and in particular vinyl.

[0537] The compounds of formula IV are preferably selected from the group of compounds of formulae IV-1 to IV-4

[0538]

[0539] wherein

[0540] alkyl and alkyl’ independently of one another denote an alkyl group having 1 to 7 C atoms, preferably having 2 to 5 C atoms,

[0541] alkenyl denotes an alkenyl group having 2 to 5 C atoms, preferably having 2 to 4 C atoms, especially preferably 2 C atoms,

[0542] 'alkenyl' indicates an alkenyl group having 2 to 5 carbon atoms, preferably 2 to 4 carbon atoms, and particularly preferably 2 to 3 carbon atoms.

[0543] alkoxy means an alkoxy group having 1 to 5 carbon atoms, preferably 2 to 4 carbon atoms.

[0544] Preferably, the LC medium comprises one or more compounds selected from formulas IV-1-1 to IV-1-4.

[0545]

[0546] Most preferably, the LC medium comprises one or more compounds of formula IV-2-1 and / or IV-2-2.

[0547]

[0548] More preferably, the LC medium comprises, in particular, a compound of formula IV-3 selected from compounds of formula IV-3-1 to IV-3-4.

[0549]

[0550]

[0551] More preferably, the LC medium comprises, in particular, a compound of formula IV-4 selected from compounds of formula IV-4-1 to IV-4-2.

[0552]

[0553] The LC medium according to the first preferred embodiment preferably further comprises one or more compounds of formula IVa.

[0554]

[0555] in

[0556] R 41 and R 42 Each of these terms independently represents a straight-chain alkyl, alkoxy, alkenyl, alkoxyalkyl, or alkoxy group having a maximum of 12 carbon atoms. express

[0557] Z 4 It represents a single bond, -CH2CH2-, -CH=CH-, -CF2O-, -OCF2-, -CH2O-, -OCH2-, -COO-, -OCO-, -C2F4-, -C4H8-, or -CF=CF-.

[0558] The following indicates preferred compounds of formula IVa:

[0559]

[0560] wherein alkyl and alkyl* each, independently of one another, denote a straight-chain alkyl group having 1 to 6 C atoms.

[0561] Preferably, the LC medium comprises at least one compound of formula IVa-1 and / or of formula IVa-2.

[0562] The proportion of compounds of formula IVa in the overall mixture is preferably at least 5% by weight.

[0563] Further preferably, the LC medium comprises one or more compounds of formula IVb-1 to IVb-3

[0564]

[0565] wherein

[0566] alkyl and alkyl* each, independently of one another, denote a straight-chain alkyl group having 1 to 6 C atoms.

[0567] alkenyl and alkenyl* each, independently of one another, denote a straight-chain alkenyl group having 2 to 6 C atoms.

[0568] The proportion of biphenyls of formula IV-1 to IV-3 in the overall mixture is preferably at least 3% by weight, in particular > 5% by weight.

[0569] Of the compounds of formula IVb-1 to IVb-3, compounds of formula IVb-2 are particularly preferred.

[0570] Particularly preferred biphenyls are

[0571]

[0572] wherein alkyl* denotes an alkyl group having 1 to 6 C atoms and preferably denotes n-propyl.

[0573] The LC medium particularly preferably comprises one or more compounds of formula IVb-1-1 and / or IVb-2-3.

[0574] In a further preferred embodiment, the LC medium according to the first preferred embodiment comprises one or more compounds of formula V

[0575]

[0576] wherein

[0577] R 51 and R 52independently of one another have the meaning indicated for R 41 and R 42 one of the meanings given and preferably denote alkyl, preferably n-alkyl, especially preferably n-alkyl having 1 to 5 C atoms; alkoxy having 1 to 7 C atoms, preferably n-alkoxy, especially 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,

[0578] identically or differently, denote

[0579]

[0580] wherein

[0581] preferably denote

[0582] Z 51 , Z 52 each, independently of one another, denote -CH2-CH2-, -CH2-O-, -CH=CH-, -C≡C-, -COO- or a single bond, preferably -CH2-CH2-, -CH2-O- or a single bond, and especially preferably a single bond, and

[0583] n is 1 or 2.

[0584] The compounds of the formula V are preferably selected from the group of the compounds of the formulae V-1 to V-16:

[0585]

[0586]

[0587] wherein R 1 and R 2 have the meanings indicated for R 2A above.

[0588] R 1 and R 2 preferably each, independently of one another, denote linear alkyl or alkenyl.

[0589] The preferred LC medium comprises one or more compounds of the formulae V-1, V-3, V-4, V-6, V-7, V-10, V-11, V-12, V-14, V-15 and / or V-16.

[0590] The LC medium according to the first preferred embodiment very preferably comprises compounds of the formulae V-10, V-12, V-16 and / or IV-1, in particular in amounts of 5 to 30%.

[0591] The following indicates preferred compounds of formula V-10:

[0592]

[0593] LC media according to the first preferred embodiment are especially preferred comprising a combination of tricyclic compounds of formula V-10a and / or V-10b with one or more bicyclic compounds of formula IV-1. The total proportion of the combination of compounds of formula V-10a and / or V-10b with one or more compounds selected from bicyclic hexyl compounds of formula IV-1 is 5 to 40 %, very preferably 15 to 35 %.

[0594] Very especially preferred LC media comprise the compounds V-10a and CC-2-3

[0595]

[0596] The compounds V-10a and IV-1-1 are preferably present in the mixture in a concentration of 15 % to 35 %, especially preferably 15 % to 25 % and particularly preferably 18 % to 22 %, based on the overall mixture.

[0597] Very especially preferred LC media comprise the compounds V-10b and IV-1-1:

[0598]

[0599] The compounds V-10b and IV-1-1 are preferably present in the mixture in a concentration of 15 % to 35 %, especially preferably 15 % to 25 % and particularly preferably 18 % to 22 %, based on the overall mixture.

[0600] Very preferred LC media comprise the following three compounds:

[0601]

[0602] The compounds V-10a, V-10b and IV-1-1 are preferably present in the mixture in a concentration of 15 % to 35 %, especially preferably 15 % to 25 % and particularly preferably 18 % to 22 %, based on the overall mixture.

[0603] Preferred LC media comprise at least one compound selected from the group of the following compounds

[0604]

[0605] wherein R 41 and R 42 , and R 51 and R 52 have the meanings indicated above. Preferably, in the compounds V-6, V-7 and IV-1, R 41 and R51 each, independently of one another, denotes alkyl or alkenyl having 1 to 6 or 2 to 6 C atoms, and R 42 and R 52 denotes alkenyl having 2 to 6 C atoms.

[0606] Further preferred LC media comprise at least one compound of formulae V-6a, V-6b, V-7a, V-7b, IV-4-1, IV-4-2, IV-3a and IV-3b:

[0607]

[0608]

[0609] wherein alkyl denotes alkyl having 1 to 6 C atoms and alkenyl denotes alkenyl having 2 to 6 C atoms.

[0610] The compounds of 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 medium according to the application in an amount of 1 to 40 % by weight, preferably 5 to 35 % by weight and very preferably 10 to 30 % by weight.

[0611] In a further preferred embodiment, the LC medium according to the first preferred embodiment additionally comprises one or more compounds of formulae VI-1 to VI-9

[0612]

[0613]

[0614] wherein

[0615] R 7 each, independently of one another, has one of the meanings indicated for R 2A in formula II A, and

[0616] w and x each, independently of one another, denote 1 to 6.

[0617] Especially preferred is an LC medium comprising at least one compound of formula V-9.

[0618] In a further preferred embodiment, the LC medium according to the first preferred embodiment additionally comprises one or more compounds of formulae VI I-1 to VI I-25,

[0619]

[0620]

[0621]

[0622]

[0623] wherein

[0624] R represents a linear alkyl or alkoxy group having 1 to 6 C atoms, (O) represents -O- or a single bond, X represents F, CI, OCF3or 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.

[0625] R preferably represents methyl, ethyl, propyl, butyl, pentyl, hexyl, methoxy, ethoxy, propoxy, butoxy, pentoxy.

[0626] X preferably represents F or OCH3, very preferably F.

[0627] The LC medium preferably comprises the bistriphenyls of the formulae VI I-1 to VI I-25 in an amount of 2 to 30 % by weight, in particular 5 to 20 % by weight.

[0628] Especially preferred are the compounds of the formulae VI I-1, VI I-2, VI I-4, VI I-20, VI I-21 and VI I-22, wherein X represents F. In these compounds, R preferably represents alkyl, and alkoxy, each having 1 to 5 C atoms. In the compounds of the formula VI I-20, R preferably represents alkyl or alkenyl, in particular alkyl. In the compounds of the formula VI I-21, R preferably represents alkyl. In the compounds of the formulae VI I-22 to VI I-25, X preferably represents F.

[0629] The bistriphenyls of the formulae VI I-1 to VI I-25 are preferably used in LC media according to the application if the mixture has a value of Δn > 0.1. Preferred LC media comprise 2 to 20 % by weight of one or more bistriphenyl compounds selected from the group of compounds of the formulae VI I-1 to VI I-25.

[0630] Further preferred embodiments according to the first preferred embodiment are listed below:

[0631] a) LC medium comprising at least one compound of the formulae Z-1 to Z-7,

[0632]

[0633] wherein R, (O) and alkyl have the meanings indicated above for formula III.

[0634] b) LC medium comprising one or more substances containing tetrahydronaphthyl or naphthyl units, for example compounds of the formulae N-1 to N-5,

[0635]

[0636]

[0637] wherein R 1N and R 2N each, independently of one another, have the meanings indicated for R 2A preferably denote linear alkyl, linear alkoxy or linear alkenyl, and

[0638] Z 1 and Z 2 each, independently of one another, denote -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.

[0639] c) LC medium comprising one or more compounds selected from the group of difluorodibenzo- chromene compounds of formula BC, chromanes of formula CR and fluorinated phenanthrenes of formulae PH-1 and PH-2,

[0640]

[0641]

[0642] wherein

[0643] R B1 , R B2 , R CR1 , R CR2 , R 1 , R 2 each, independently of one another, have the meanings of R 2A c is 0, 1 or 2. R 1 and R 2 preferably, independently of one another, denote alkyl or alkoxy having 1 to 6 C atoms.

[0644] The LC medium preferably comprises the compounds of formulae BC, CR, PH-1, PH-2 in an amount of 3 to 20 % by weight, in particular in an amount of 3 to 15 % by weight.

[0645] Especially preferred compounds of formulae BC and CR are the compounds BC-1 to BC-7 and CR-1 to CR-5,

[0646]

[0647]

[0648] wherein alkyl and alkyl* each, independently of one another, denote a straight-chain alkyl group having 1 to 6 C atoms, and

[0649] alkenyl and alkenyl* each, independently of one another, denote a straight-chain alkenyl group having 2 to 6 C atoms.

[0650] Very particularly preferred are LC media comprising one, two or three compounds of formulae BC-2, BF-1 and / or BF-2.

[0651] d) LC medium comprising one or more indane compounds of formula In,

[0652]

[0653] wherein

[0654] R 11 , R 12 , R 13 each, independently of one another, denote a straight-chain alkyl, alkoxy, alkoxyalkyl or alkenyl group having 1 to 6 C atoms,

[0655] R 12 and R 13 further denote halogen, preferably F,

[0656] denote

[0657]

[0658] i denotes 0, 1 or 2.

[0659] Preferred compounds of formula In are the compounds of formulae In-1 to In-16 indicated below:

[0660]

[0661]

[0662]

[0663] Especially preferred are the compounds of formulae In-1, In-2, In-3 and In-4.

[0664] The compounds of formula In and of the subformulae In-1 to In-16 are preferably used in the LC medium according to the application in concentrations of > 5% by weight, in particular 5% to 30% by weight and very preferably 5% to 25% by weight.

[0665] e) LC medium comprising one or more compounds of formulae L-1 to L-5,

[0666]

[0667] wherein

[0668] R and R 1 each, independently of one another, have the meanings indicated above for R 2A in formula II A, and alkyl denotes an alkyl radical having 1 to 6 C atoms, and the parameter s denotes 1 or 2.

[0669] The compounds of formulae L-1 to L-5 are preferably used in concentrations of 5 to 50% by weight, in particular 5 to 40% by weight and very preferably 10 to 40% by weight.

[0670] f) LC medium comprising one or more compounds of formula IIA-Y

[0671]

[0672] wherein R 11 and R 12 have the meanings indicated above for R 2A in formula II A, and L 1 and L 2 denote, identically or differently, F or CI.

[0673] Preferred compounds of formula IIA-Y are selected from the group consisting of the following subformulae:

[0674]

[0675]

[0676] wherein Alkyl and Alkyl* each, independently of one another, denote a straight-chain alkyl radical having 1 to 6 C atoms, Alkoxy denotes a straight-chain alkoxy radical having 1 to 6 C atoms, Alkenyl and Alkenyl* each, independently of one another, denote a straight-chain alkenyl radical having 2 to 6 C atoms, and O denotes an oxygen atom or a single bond. Alkenyl and Alkenyl* preferably denote 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-.

[0677] Especially preferred compounds of formula IIA-Y are selected from the group consisting of the following subformulae:

[0678]

[0679] Alkoxy and Alkoxy* have the meanings defined above and preferably represent methoxy, ethoxy, n-propoxy, n-butyloxy or n-pentoxy.

[0680] g) An LC medium comprising one or more compounds selected from the following tetraphenyl compounds:

[0681]

[0682] in

[0683] R Q It is an alkyl, alkoxy, oxalyl, or alkoxyalkyl group having 1 to 9 carbon atoms, or an alkenyl or alkenyloxy group having 2 to 9 carbon atoms, all of which are optionally fluorinated.

[0684] X Q It is F, Cl, a haloalkyl or alkoxy group having 1 to 6 carbon atoms, or a haloalkenyl or alkenoxy group having 2 to 6 carbon atoms.

[0685] L Q1 To L Q6 H or F are independent of each other, where L Q1 To L Q6 At least one of them is F.

[0686] The preferred compound of formula Q is wherein R Q This refers to straight-chain alkyl groups having 2 to 6 carbon atoms, with ethyl, n-propyl, or n-butyl being the most preferred.

[0687] The preferred compound of formula Q is wherein L Q3 and L Q4 Those are those of F. A further preferred compound of formula Q is one in which L... Q3 L Q4 and L Q1 and L Q2 Those whose one or both are F.

[0688] The preferred compound of formula Q is X. Q Those that represent F or OCF3, with F being the most preferred.

[0689] Compound Q is preferably selected from the following sub-formulas

[0690]

[0691] Where R Q It has one of the meanings of formula Q or its preferred meaning as given above and below, and is preferably ethyl, n-propyl or n-butyl.

[0692] Especially preferred are compounds of formula Q1, in particular those wherein R Q is n-propyl.

[0693] Preferably, the proportion of compounds of formula Q in the LC host mixture is > 0 to ≤ 5% by weight, very preferably 0.05 to 2% by weight, more preferably 0.1 to 1 % by weight, most preferably 0.1 to 0.8% by weight.

[0694] Preferably, the LC medium contains 1 to 5, preferably 1 or 2 compounds of formula Q.

[0695] The addition of the diphenvl compounds of formula Q to the LC host mixture enables a reduction of ODF inhomogeneity while maintaining high UV absorption, enables fast and complete polymerization, enables strong and fast generation of tilt angles and increases the UV stability of the LC medium.

[0696] Furthermore, the addition of compounds of formula Q having a positive dielectric anisotropy to LC media having a negative dielectric anisotropy allows a better control of the values of the dielectric constants ε || and ε ⊥ and in particular enables a high dielectric constant ε || value to be achieved while keeping the dielectric anisotropy Δε constant, thereby reducing the kick-back voltage and reducing image sticking.

[0697] The LC medium according to the first preferred embodiment preferably comprises

[0698] one or more compounds of formula I, preferably of formula II, very preferably selected from formulae II-1 to II-10, preferably in a total concentration in the range of 0.01 to 2.0%, more preferably 0.1 to 1.0%, most preferably 0.2 to 0.8%,

[0699] and / or

[0700] one or more compounds of formula III, preferably in a total concentration in the range of 5 to 30%, more preferably 7 to 25%, especially preferably 10 to 20%;

[0701] and / or

[0702] one or more compounds of formula III and IV, preferably in a total concentration in the range of 30 to 45%;

[0703] and / or

[0704] one or more compounds of formula IV, preferably in a total concentration in the range of 35 to 70%, more preferably 40 to 65%, especially preferably 45 to 60%;

[0705] and / or

[0706] - one or more compounds of formula IV-3, preferably in a total concentration in the range of 35 to 60 %, more preferably 40 to 55 %, particularly preferably 45 to 50 %;

[0707] and / or

[0708] - one or more compounds of formula III-2, preferably of formula III-2-6, preferably in a total concentration in the range of 2 to 25 %, more preferably 5 to 15 %, particularly preferably 5 to 12 %.

[0709] In particular, the medium comprises

[0710] - 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 in the range of 5 to 30 %, preferably 10 to 20 %;

[0711] and / or

[0712] - one or more compounds PY-n-Om, in particular PY-3-O2 and / or PY-1-O2, preferably in a total concentration in the range of 5 to 30 %, preferably 5 to 20 %;

[0713] and / or

[0714] - CPY-n-Om, in particular CPY-2-O2, CPY-3-O2 and / or CPY-5-O2, in a concentration of > 5 %, in particular 7 to 20 %, based on the overall mixture,

[0715] and / or

[0716] - 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, in a concentration of > 3 %, in particular 5 to 15 %, based on the overall mixture,

[0717] and / or

[0718] - one or more compounds CPY-n-Om, preferably CPY-2-O2 and / or CPY-3-O2, in a concentration of > 3 %, in particular 5 to 15 %, based on the overall mixture;

[0719] and / or

[0720] - CLY-n-Om, preferably CLY-2-O4, CLY-3-O2 and / or CLY-3-O3, in a concentration of > 5 %, in particular 10 to 30 %, very preferably 15 to 20 %, based on the overall mixture;

[0721] and / or

[0722] - CPY-n-Om and CY-n-Om, preferably in a concentration of 10% to 80%, based on the overall mixture,

[0723] and / or

[0724] - 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 concentration of 5% to 20%, more preferably 10% to 15%, based on the overall mixture,

[0725] and / or

[0726] - CC-3-V, preferably in a concentration of 5% to 50%, based on the overall mixture,

[0727] and / or

[0728] - a compound of formula CC-3-V1 in a total concentration in the range of 5% to 40%, more preferably 15% to 35%, especially preferably 20% to 30%,

[0729] and / or

[0730] - one or more compounds of formula B-nO-Om and / or B(S)-nO-Om, in particular the compounds B(S)-2O-O4 and / or B(S)-2O-O5, preferably in a concentration in the range of 2% to 12%,

[0731] and / or

[0732] - 0.1% to 3% of the compound PPGU-3-F.

[0733] In a second preferred embodiment, the LC medium contains an LC host mixture based on compounds having a positive dielectric anisotropy. This LC medium is especially suitable for use in PS-OCB, PS-TN, PS-Posi-VA, PS-IPS, PS-FFS or SA-HB-FFS displays.

[0734]

[0735] wherein each group independently of each other and on each occurrence identically or differently has the following meanings:

[0736] each independently of one another

[0737] and on each occurrence identically or differently is

[0738]

[0739] R21 R 31 each, independently of one another, 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,

[0740] X 0 is F, Cl, halogenated alkyl or alkoxy having 1 to 6 C atoms or halogenated alkenyl or alkenyloxy having 2 to 6 C atoms,

[0741] Z 31 is -CH2CH2-, -CF2CF2-, -COO-, trans-CH=CH-, trans-CF=CF-, -CH2O- or a single bond, preferably -CH2CH2-, -COO-, trans-CH=CH- or a single bond, very preferably -COO-, trans-CH=CH- or a single bond,

[0742] L 21 , L 22 , L 31 , L 32 each, independently of one another, is H or F, g0, 1, 2 or 3.

[0743] In the compounds of the formulae A and B, X 0 is preferably F, Cl, CF3, CHF2, OCF3, OCHF2, OCFHCF3, OCFHCHF2, OCFHCHF2, OCF2CH3, OCF2CHF2, OCF2CHF2, OCF2CF2CHF2, OCF2CF2CHF2, OCFHCF2CF3, OCFHCF2CHF2, OCF2CF2CF3, OCF2CF2CCIF2, OCCIFCF2CF3 or CH=CF2, very preferably F or OCF3, most preferably F.

[0744] In the compounds of the formulae A and B, R 21 and R 31 are preferably selected from linear alkyl or alkoxy having 1, 2, 3, 4, 5 or 6 C atoms and linear alkenyl having 2, 3, 4, 5, 6 or 7 C atoms.

[0745] In the compounds of the formulae A and B, g is preferably 1 or 2.

[0746] In the compounds of the formula B, Z 31 is preferably COO, trans-CH=CH or a single bond, very preferably COO or a single bond.

[0747] Preferably, the component B) of the LC medium comprises one or more compounds of the formula A selected from the group consisting of the following formulae:

[0748]

[0749]

[0750] wherein A 21 , A 22 , R 21 , X 0 , L 21 and L 22 have the meanings given in formula A, L 23 and L 24 are each, independently of one another, H or F, and X 0 is preferably F. Especially preferred are compounds of the formulae A1 and A2.

[0751] Especially preferred compounds of the formula A1 are selected from the group consisting of the following subformulae:

[0752]

[0753]

[0754] wherein R 21 , X 0 , L 21 and L 22 have the meanings given in formula A1, L 23 , L 24 , L 25 and L 26 are each, independently of one another, H or F, and X 0 is preferably F.

[0755] Very preferred compounds of the formula A1 are selected from the group consisting of the following subformulae:

[0756]

[0757]

[0758] wherein R 21 is as defined in formula A1.

[0759] Especially preferred compounds of the formula A2 are selected from the group consisting of the following subformulae:

[0760]

[0761]

[0762]

[0763] wherein R 21 , X 0 , L 21 and L 22L has the meaning given in formula A2, and X 23 , L 24 , L 25 and L 26 each, independently of one another, H or F, and X 0 is preferably F.

[0764] Very preferred compounds of formula A2 are selected from the group consisting of the following subformulae:

[0765]

[0766]

[0767]

[0768] wherein R 21 and X 0 are as defined in formula A2.

[0769] Especially preferred compounds of formula A3 are selected from the group consisting of the following subformulae:

[0770]

[0771] wherein R 21 , X 0 , L 21 and L 22 have the meaning given in formula A3, and X 0 is preferably F. Especially preferred compounds of formula A4 are selected from the group consisting of the following subformulae:

[0772]

[0773] wherein R 21 are as defined in formula A4.

[0774] Preferably, component B) of the LC medium comprises one or more compounds of formula B, which are selected from the group consisting of the following formulae:

[0775]

[0776] wherein g, A 31 , A 32 , R 31 , X 0 , L 31 and L 32 have the meaning given in formula B, and X 0 is preferably F. Especially preferred are compounds of formula B1 and B2.

[0777] Especially preferred compounds of formula B1 are selected from the group consisting of the following subformulae:

[0778]

[0779]

[0780] wherein R 31 , X 0 , L 31 and L 32 have the meanings given in formula B1, and X 0 is preferably F. Very particularly preferred compounds of formula B1 a are selected from the group consisting of the following subformulae:

[0781]

[0782] wherein R 31 are as defined in formula B1.

[0783] Very particularly preferred compounds of formula B1 b are selected from the group consisting of the following subformulae:

[0784]

[0785] wherein R 31 are as defined in formula B1.

[0786] Especially preferred compounds of formula B2 are selected from the group consisting of the following subformulae:

[0787]

[0788]

[0789]

[0790] wherein R 31 , X 0 , L 31 and L 32 have the meanings given in formula B2, L 33 , L 34 , L 35 and L 36 are each, independently of one another, H or F, and X 0 is preferably F.

[0791] Very particularly preferred compounds of formula B2 are selected from the group consisting of the following subformulae:

[0792]

[0793] wherein R 31 are as defined in formula B2.

[0794] Very particularly preferred compounds of formula B2b are selected from the group consisting of the following subformulae:

[0795]

[0796] wherein R 31 as defined in formula B2.

[0797] Very particularly preferred compounds of the formula B2c are selected from the group consisting of the following subformulae:

[0798]

[0799]

[0800] wherein R 31 as defined in formula B2.

[0801] Very particularly preferred compounds of the formula B2d and B2e are selected from the group consisting of the following subformulae:

[0802]

[0803] wherein R 31 as defined in formula B2.

[0804] Very particularly preferred compounds of the formula B2f are selected from the group consisting of the following subformulae:

[0805]

[0806]

[0807] wherein R 31 as defined in formula B2.

[0808] Very particularly preferred compounds of the formula B2g are selected from the group consisting of the following subformulae:

[0809]

[0810]

[0811] wherein R 31 as defined in formula B2.

[0812] Very particularly preferred compounds of the formula B2h are selected from the group consisting of the following subformulae:

[0813]

[0814] wherein R 31 as defined in formula B2.

[0815] Very particularly preferred compounds of the formula B2i are selected from the group consisting of the following subformulae:

[0816]

[0817] wherein R 31 as defined in formula B2.

[0818] Very particularly preferred compounds of formula B2k are selected from the group consisting of the following subformulae:

[0819]

[0820] wherein R 31 as defined in formula B2.

[0821] Very particularly preferred compounds of formula B2l are selected from the group consisting of the following subformulae:

[0822]

[0823] wherein R 31 as defined in formula B2.

[0824] Instead of or in addition to compounds of formula B1 and / or B2, component B) of the LC medium can also comprise one or more compounds of formula B3 as defined above.

[0825] Especially preferred compounds of formula B3 are selected from the group consisting of the following subformulae:

[0826]

[0827]

[0828] wherein R 31 as defined in formula B3.

[0829] Preferably, component B) of the LC medium comprises one or more compounds of formula C in addition to compounds of formula A and / or B

[0830]

[0831] wherein each group has the following meaning:

[0832] each, independently of one another and

[0833] on each occurrence, identically or differently

[0834]

[0835] R 41 , R 42 each, independently of one another, 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,

[0836] Z41 , Z 42 are each, independently of one another, -CH2CH2-, -COO-, trans-CH=CH-, trans-CF=CF-, -CH2O-, -CF2O-, -CºC- or a single bond, preferably a single bond,

[0837] h is 0, 1, 2 or 3.

[0838] In the compounds of the formula C, R 41 and R 42 are preferably selected from linear alkyl or alkoxy having 1, 2, 3, 4, 5 or 6 C atoms and linear alkenyl having 2, 3, 4, 5, 6 or 7 C atoms.

[0839] In the compounds of the formula C, h is preferably 0, 1 or 2.

[0840] In the compounds of the formula C, Z 41 and Z 42 are preferably selected from COO, trans-CH=CH and a single bond, very preferably from COO and a single bond.

[0841] Especially preferred compounds of the formula C are selected from the group consisting of the following subformulae:

[0842]

[0843]

[0844] wherein R 41 and R 42 have the meanings given in formula C and preferably each, independently of one another, denote alkyl, alkoxy, fluorinated alkyl or fluorinated alkoxy having 1 to 7 C atoms or alkenyl, alkenyloxy, alkoxyalkyl or fluorinated alkenyl having 2 to 7 C atoms.

[0845] Further preferably, component B) of the LC medium comprises one or more compounds of the formula D

[0846]

[0847] wherein A 41 , A 42 , Z 41 , Z 42 , R 41 , R 42 and h have the meanings given in formula C or one of the preferred meanings given above.

[0848] Especially preferred compounds of the formula D are selected from the group consisting of the following subformulae:

[0849]

[0850] wherein R 41 and R 42 have the meanings given in formula D and R 41 preferably denotes alkyl, and in formula D1, R 42 preferably denotes alkenyl, especially preferably -(CH2)2-CH=CH-CH3, and in formula D2, R 42 preferably denotes alkyl, -(CH2)2-CH=CH2 or -(CH2)2-CH=CH-CH3.

[0851] Further preferably, component B) of the LC medium comprises, in addition to the compounds of the formulae A and / or B, one or more compounds of the formula E containing alkenyl groups

[0852]

[0853] wherein the individual radicals are on each occurrence identically or differently and each, independently of one another, have the following meanings:

[0854]

[0855] R A1 is alkenyl having 2 to 9 C atoms, if at least one of the rings X, Y and Z denotes cyclohexenyl, also one of the meanings of R A2 ,

[0856] R A2 is alkyl having 1 to 12 C atoms, furthermore in which one or two non-adjacent CH2groups can be replaced by -O-, -CH=CH-, -CO-, -OCO- or -COO- without being directly connected to one another by an O atom,

[0857] x is 1 or 2.

[0858] R A2 is preferably linear alkyl or alkoxy having 1 to 8 C atoms or linear alkenyl having 2 to 7 C atoms.

[0859] Preferably, the compounds of the formula E are selected from the following subformulae:

[0860]

[0861]

[0862] in which alkyl and alkyl* each, independently of one another, denote a straight-chain alkyl radical having 1 to 6 C atoms, and alkenyl and alkenyl* each, independently of one another, denote a straight-chain alkenyl radical having 2 to 7 C atoms. Alkenyl and alkenyl* preferably denote 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-.

[0863] Very particularly preferred compounds of the formula E are selected from the following subformulae:

[0864]

[0865] in which m denotes 1, 2, 3, 4, 5 or 6, i denotes 0, 1, 2 or 3, and R b1 denote H, CH3or C2H5.

[0866] Very particularly preferred compounds of the formula E are selected from the following subformulae:

[0867]

[0868] Most preferred are the compounds of the formulae E1a2, E1a5, E3a1 and E6a1.

[0869] Further preferably, component B) of the LC medium comprises, in addition to the compounds of the formulae A and / or B, one or more compounds of the formula F

[0870]

[0871] in which the individual radicals, independently of one another and on each occurrence identically or differently, have the following meanings:

[0872] denote

[0873]

[0874] R 21 , R 31 each, independently of one another, 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,

[0875] X 0 is F, Cl, halogenated alkyl or alkoxy having 1 to 6 C atoms or halogenated alkenyl or alkenyloxy having 2 to 6 C atoms,

[0876] Z 21The bond type is -CH2CH2-, -CF2CF2-, -COO-, trans-CH=CH-, trans-CF=CF-, -CH2O-, or a single bond, preferably -CH2CH2-, -COO-, trans-CH=CH-, or a single bond, especially -COO-, trans-CH=CH-, or a single bond.

[0877] L 21 L 22 L 23 L 24 Each is independently H or F.

[0878] g can be 0, 1, 2, or 3.

[0879] The preferred compound of formula F is selected from the group consisting of the following formulas:

[0880]

[0881]

[0882] Where R 21 X 0 L 21 and L 22 Having the meaning given in formula F, L 25 and L 26 Each is independently H or F, and X 0 F is preferred.

[0883] The most preferred compounds of formulas F1-F3 are selected from the group consisting of the following formulas:

[0884]

[0885]

[0886] Where R 21 As defined in equation F1.

[0887] In the LC bulk mixture, the concentration of compounds of formula A and B is preferably 2-60%, very preferably 3-45%, and most preferably 4-35%.

[0888] In the LC bulk mixture, the concentration of compounds of formula C and D is preferably 2-70%, very preferably 5-65%, and most preferably 10-60%.

[0889] In the LC bulk mixture, the concentration of compound of formula E is preferably 5-50%, and very preferably 5-35%.

[0890] In the LC bulk mixture, the concentration of compound of formula F is preferably 2-30%, and very preferably 5-20%.

[0891] Further preferred embodiments of this second preferred embodiment of the present application are listed below, including any combination thereof.

[0892] 2a) The LC host mixture comprises one or more compounds of formula A and / or B having positive dielectric anisotropy, preferably Δε > 15.

[0893] 2b) The LC host mixture comprises one or more compounds selected from the group consisting of formulae A1a2, A1b1, A1d1, A1f1, A2a1, A2h1, A2l2, A2k1, B2h3, B2l1, F1a. The proportion of these compounds in the LC host mixture is preferably 4 to 40 %, very preferably 5 to 35 %.

[0894] 2c) The LC host mixture comprises one or more compounds selected from the group consisting of formulae B2c1, B2c4, B2f4, C14. The proportion of these compounds in the LC host mixture is preferably 4 to 40 %, very preferably 5 to 35 %.

[0895] 2d) The LC host mixture comprises one or more compounds from the group consisting of formulae C3, C4, C5, C9 and D2. The proportion of these compounds in the LC host mixture is preferably 8 to 70 %, very preferably 10 to 60 %.

[0896] 2e) The LC host mixture comprises one or more compounds selected from the group consisting of formulae E1, E3 and E6 (preferably E1a, E3a and E6a, very preferably E1a2, E1a5, E3a1 and E6a1). The proportion of these compounds in the LC host mixture is preferably 5 to 60 %, very preferably 10 to 50 %.

[0897] The combination of the compounds of the above-mentioned preferred embodiments with the above-mentioned polymerized compounds leads to low threshold voltage, low rotational viscosity and very good low temperature stability in the LC medium according to the present application, while high clearing point and high HR values, and allows a particularly low tilt angle to be established quickly (i.e. a large tilt) in a PSA display. In particular, the LC medium shows a significantly shortened response time, in particular also grey scale response time, in a PSA display relative to the prior art media.

[0898] The LC medium and the LC host mixture of the present application preferably have a nematic phase range of at least 80 K, particularly preferably at least 100 K, and a rotational viscosity of ≤ 250 mPa-s, preferably ≤ 200 mPa-s at 20 °C.

[0899] The LC medium according to the present application has advantageously a nematic phase preferably in the range of > -20°C to < 70°C, especially preferably in the range of > -30°C to < 80°C, very preferably in the range of > -40°C to < 90°C.

[0900] The LC medium according to the present application preferably has a clearing point of 70°C or more, preferably 74°C or more.

[0901] Here, the expression "having a nematic phase" means on the one hand that no smectic phase is observed at low temperatures and no crystallization is observed, and on the other hand that no clearing occurs when heating from the nematic phase. The investigations at low temperatures are carried out in a flow viscosimeter at the respective temperature and checked by storage in a test cell having a layer thickness corresponding to electro-optical applications for at least 100 hours. If the storage stability at a temperature of -20°C is 1000 hours or more in the respective test cell, the medium is referred to as stable at this temperature. At temperatures of -30°C and -40°C, the respective times are 500 hours and 250 hours, respectively. At high temperatures, the clearing point is measured in capillaries by conventional methods.

[0902] The LC medium preferably has a nematic phase range of at least 60 K and a flow viscosity v20° C of at most 30 mm 2 ·s -1 20 .

[0903] The mixture is nematic at temperatures of -20°C or less, preferably -30°C or less, very preferably -40°C or less.

[0904] The birefringence Δn in the LC medium is typically in the range of 0.07 to 0.16, preferably in the range of 0.08 to 0.15, very preferably in the range of 0.09 to 0.14.

[0905] In a preferred embodiment of the present application, the LC medium has a birefringence in the range of 0.090 to 0.110, preferably 0.095 to 0.105, in particular 0.100 to 0.105.

[0906] In another preferred embodiment of the present application, the LC medium has a birefringence of 0.120 or more, preferably in the range of 0.125 to 0.145, more preferably 0.130 to 0.140.

[0907] The rotary viscosity γ1 at 20°C is preferably ≤ 120 mPa-s, in particular ≤ 100 mPa-s.

[0908] In a preferred embodiment, the rotary viscosity γ1 at 20°C is ≤ 100 mPa-s, in particular ≤ 95 mPa-s. ​

[0909] The liquid-crystalline medium according to the present application has a comparatively low threshold voltage value (V0). It is preferably in the range from 1.7 V to 3.0 V, particularly preferably < 2.7 V and very particularly preferably < 2.5 V.

[0910] Unless explicitly stated otherwise, the term "threshold voltage" for the present application relates to the capacitive threshold (V0), also called Freedericks threshold.

[0911] In addition, the liquid-crystalline medium according to the present application has a high voltage holding ratio value within the liquid-crystalline cell.

[0912] Generally, liquid-crystalline media having a low addressing voltage or threshold voltage exhibit a lower voltage holding ratio than those having a higher addressing voltage or threshold voltage, and vice versa.

[0913] In VA type displays according to the present application, the molecules in the LC medium layer in the off state are aligned perpendicular to the electrode surface (vertically) or have a tilted vertical alignment. Upon application of a voltage to the electrodes, the LC molecules undergo a re-alignment, in which the longitudinal axes of the molecules are parallel to the electrode surface.

[0914] The LC medium according to the present application for use in PS-VA, PS-UB-FFS and SA-VA type displays based on compounds having a negative dielectric anisotropy according to the first preferred embodiment has a negative dielectric anisotropy Δε at 20°C and 1 kHz of preferably -0.5 to -10, more preferably -1.5 to -8.0, particularly -2.5 to -7.5, even more preferably -2.0 to -4.0, most preferably -2.5 to -3.5.

[0915] The birefringence Δn in the LC medium according to the present application for use in PS-VA, PS-UB-FFS and SA-VA type displays is preferably below 0.16, particularly preferably 0.06 to 0.14, very particularly preferably 0.07 to 0.12.

[0916] The nematic LC medium according to the present application based on compounds having a negative dielectric anisotropy according to the first preferred embodiment preferably comprises two components A1 and A2, which themselves consist of one or more individual compounds.

[0917] Component A1 has a pronounced negative dielectric anisotropy and makes it possible to obtain a nematic phase with a dielectric anisotropy < -0.5. In addition to one or more compounds of the formula I, it preferably comprises compounds of the formulae IIIA, IIIB and / or IIIC, and one or more compounds of the formula IV-1.

[0918] The proportion of component A1 is preferably between 45% and 100%, in particular between 60% and 85%.

[0919] For component A1, preference is given to selecting one (or more) individual compounds having a Δε value of < -0.8. The more negative this value, the smaller the proportion of A1 in the overall mixture.

[0920] Component A2 has a pronounced nematicity and a flow viscosity at 20°C of not more than 30 mm 2 · s -1 , preferably not more than 25 mm 2 · s -1 .

[0921] A person skilled in the art can find a variety of suitable materials in the literature. Particularly preferred are compounds of the formula O-17.

[0922] Individual compounds which are particularly preferred in component A2 are very low-viscosity nematic liquid crystals having a flow viscosity at 20°C of not more than 18 mm 2 · s -1 , preferably not more than 12 mm 2 · s -1 .

[0923] Component A2 is monotropic or diprotic nematic, has no smectic phase and can prevent the occurrence of a smectic phase in the LC medium on falling to very low temperatures. By way of example, if individual highly nematic materials are added to a smectic LC mixture, the nematicity of these materials can be compared by the degree of suppression of the smectic phase achieved.

[0924] The nematic LC medium according to the application based on compounds having a negative dielectric anisotropy according to the first preferred embodiment can optionally also comprise a component A3 comprising compounds having a dielectric anisotropy Δε > 1.5. These so-called positive compounds are generally present in mixtures with a negative dielectric anisotropy in amounts of < 20% by weight, based on the overall mixture.

[0925] In addition to one or more compounds of the formula I, the LC medium preferably comprises 4 to 15, in particular 5 to 12 and especially preferably < 10 compounds of the formulae I IA, I IB and / or I IC and optionally one or more compounds of the formula IV-1.

[0926] In addition to the compounds of the formula I and the formulae I IA, I IB and / or I IC and optionally the compounds of the formula IV-1, further components can also be present, for example in amounts of up to 45%, but preferably up to 35%, in particular up to 10%, of the overall mixture.

[0927] The other components are preferably selected from nematic or nematogenic substances, in particular from the following classes of known substances: azoxybenzene, benzidene aniline, biphenyl, terphenyl, benzophenone or cyclohexanophenone, phenylcyclohexane carboxylate or cyclohexylcyclohexane carboxylate, phenylcyclohexane, cyclohexylbiphenyl, cyclohexylcyclohexane, cyclohexyl naphthalene, 1,4-biscyclohexylbiphenyl or cyclohexylpyrimidine, phenyldioxane or cyclohexyldioxane, optionally halogenated stilbene, benzyl phenyl ether, diphenylacetylene and substituted cinnamic esters.

[0928] The most important compounds suitable as components for liquid crystal phases of this type can be characterized by the formula OC

[0929] R 20 -L-G-E-R 21 OC

[0930] where L and E each denote a carbocyclic or heterocyclic ring system, which is formed from groups from the following substances: 1,4-disubstituted benzene and cyclohexane rings, 4,4'-disubstituted biphenyl, phenylcyclohexane and cyclohexylcyclohexane systems, 2,5-disubstituted pyrimidine and 1,3-disubstituted pyrimidine, 2,6-disubstituted naphthalene, dihydronaphthalene and tetrahydronaphthalene, quinazoline and tetrahydroquinazoline, alkylcyclohexane, 2,6-disubstituted naphthalene, dihydronaphthalene and tetrahydronaphthalene, quinazoline and tetrahydroquinazoline,

[0931] G denotes -CH=CH--N(O)=N-

[0932] -CH=CQ--CH=N(O)-

[0933] -C≡C--CH2-CH2-

[0934] -CO-O--CH2-O-

[0935] -CO-S--CH2-S-

[0936] -CH=N--COO-Phe-COO-

[0937] -CF2O--CF=CF-

[0938] -OCF2--OCH2-

[0939] -(CH2)4--(CH2)3O-

[0940] or a C-C single bond,

[0941] Q denotes halogen, preferably chlorine, or -CN, and

[0942] R 20 and R 21each denotes alkyl, alkenyl, alkoxy, alkoxyalkyl or alkoxycarbonyloxy of up to 18, preferably up to 8 carbon atoms, or one of these radicals alternatively denotes CN, NC, NO2, NCS, CF3, SF5, OCF3, F, CI or Br.

[0943] In most of these compounds, R 20 and R 21 are different from each other, one of these radicals is usually an alkyl or alkoxy group. Other variants of the proposed substituents are also common. Many of such substances or also mixtures thereof are commercially available. All these substances can be prepared by methods known from the literature.

[0944] In the OCB-type displays according to the application, the molecules in the layer of the LC medium have a "bend" alignment. Upon application of a voltage, a re-alignment of the LC molecules takes place and the longitudinal molecular axes are perpendicular to the electrode surface.

[0945] Based on compounds having a positive dielectric anisotropy according to the second preferred embodiment, the LC medium according to the application used in PS-TN, PS- positive-VA, PS-IPS or PS-FFS and SA-FFS displays has a positive dielectric anisotropy Δε of +2 to +30, particularly preferably +3 to +20 at 20°C and 1 kHz.

[0946] The birefringence Δn of the LC medium according to the application used in PS-OCB displays is preferably 0.14 to 0.22, particularly preferably 0.16 to 0.22.

[0947] The birefringence Δn of the LC medium according to the application used in PS-TN, PS- positive-VA, PS-IPS or PS-FFS and SA-FFS displays is preferably 0.07 to 0.15, particularly preferably 0.08 to 0.13.

[0948] The LC medium according to the application can also comprise further additives known to the person skilled in the art and described in the literature, such as polymerization initiators, inhibitors, stabilizers, surface-active substances or chiral dopants. These substances can be polymerizable or non-polymerizable. Polymerizable additives are thus classified under the polymerizable components or component A). Non-polymerizable additives are thus classified under the non-polymerizable components or component B).

[0949] Furthermore, it is possible to add, for example, 0 to 15 % by weight of pleochroic dyes, furthermore also nanoparticles, electrically conductive salts, preferably ethyldimethyldodecylammonium 4-hexyloxybenzoate, tetrabutylammonium tetraphenylborate or complexing salts of crown ethers (see, for example, Haller et al., Mol. Cryst. Liq. Cryst. 1998, 305, 183) to the LC medium.24 substances are described, for example, in DE-A 22 09 127, 22 40 864, 23 21 632, 23 38 281, 24 50 088, 26 37 430 and 28 53 728.

[0950] The individual components of the preferred embodiments a) to z) of the LC medium according to the application are known or the processes for their preparation can be derived from the prior art by the person skilled in the relevant art, since they are based on standard methods 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.

[0951] The LC media which can be used according to the application are prepared in a manner known per se, for example by mixing one or more of the above-mentioned compounds with one or more polymerisable compounds as defined above, and optionally with further liquid-crystalline compounds and / or additives. As a rule, the desired amounts of the components used in smaller amounts are dissolved in the components which constitute the main constituents, which is advantageously carried out at elevated temperature. It is also possible to mix solutions of the components in organic solvents, for example acetone, chloroform or methanol, and to remove the solvent again, for example by distillation, after thorough mixing. The application also relates to a process for the preparation of LC media according to the application.

[0952] It goes without saying that the LC media according to the application can, in addition, comprise compounds in which, for example, H, N, O, CI, F are replaced by corresponding isotopes, such as deuterium, for the person skilled in the art.

[0953] The following examples illustrate the application but do not limit the application. They show, however, the person skilled in the art preferred mixture concepts, and the compounds used preferably and their respective concentrations, and their combination with one another. Furthermore, the examples clarify which properties and combinations of properties are obtainable.

[0954] Preferred mixture components are shown in Tables A1 and A2 below. The compounds shown in Table A1 are suitable, inter alia, for use in LC mixtures having positive dielectric anisotropy. The compounds shown in Table A2 are suitable, inter alia, for use in LC mixtures having negative dielectric anisotropy.

[0955] Table A1

[0956] In Table A1, m and n are independently of each other an integer from 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 means C m H 2m+1 or OC m H 2m+1 .

[0957]

[0958]

[0959]

[0960]

[0961]

[0962]

[0963]

[0964]

[0965]

[0966] Table A2

[0967] In Table A2, m and n are independently of each other an integer from 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 means C m H 2m+1 or OC m H 2m+1 .

[0968]

[0969]

[0970]

[0971]

[0972]

[0973]

[0974]

[0975]

[0976]

[0977]

[0978]

[0979]

[0980]

[0981]

[0982]

[0983]

[0984]

[0985]

[0986]

[0987]

[0988]

[0989] In a first preferred embodiment of the present application, the LC medium according to the present application, in particular those having a positive dielectric anisotropy, comprises one or more compounds selected from the group consisting of compounds from Table A1.

[0990] In a second preferred embodiment of the present application, the LC medium according to the present application, in particular those having a negative dielectric anisotropy, comprises one or more compounds selected from the group consisting of compounds from Table A2.

[0991] Table B

[0992] Table B shows possible chiral dopants which can be added to the LC medium according to the present application.

[0993]

[0994]

[0995] The LC medium preferably comprises 0 to 10 % by weight, in particular 0.01 to 5 % by weight, particularly preferably 0.1 to 3 % by weight, of the dopant. The LC medium preferably comprises one or more dopants selected from the group consisting of compounds from Table B.

[0996] Table C

[0997] Table C shows possible stabilizers which can be added to the LC medium according to the present application. n denotes an integer from 1 to 12, preferably 1, 2, 3, 4, 5, 6, 7 or 8, and terminal methyl groups are not shown.

[0998]

[0999]

[1000]

[1001]

[1002]

[1003]

[1004]

[1005] The LC medium preferably comprises 0 to 10 wt.-%, in particular 1 ppm to 5 wt.-%, particularly preferably 1 ppm to 1 wt.-%, of stabilizers. The LC medium preferably comprises one or more stabilizers selected from the group consisting of compounds from Table C.

[1006] Table D

[1007] Table D shows illustrative reactive mesogenic compounds which can be used in the LC medium according to the present application.

[1008]

[1009]

[1010]

[1011]

[1012]

[1013]

[1014]

[1015]

[1016]

[1017]

[1018]

[1019]

[1020]

[1021]

[1022]

[1023]

[1024]

[1025]

[1026]

[1027]

[1028]

[1029] In a preferred embodiment, the mixture of the present application comprises one or more polymerisable compounds, which are preferably selected from the group consisting of polymerisable compounds of formulae 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.

[1030] In another preferred embodiment, the mixture of the present application comprises one or more polymerisable 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.

[1031] Table E

[1032] Table E shows self-alignment additives for vertical alignment, which can be used in LC media for SA-VA and SA-FFS displays of the present application together with polymerisable compounds of formula I:

[1033]

[1034]

[1035]

[1036]

[1037]

[1038]

[1039]

[1040]

[1041]

[1042]

[1043]

[1044] In a preferred embodiment, the LC medium, the SA-VA and the SA-FFS display according to the present application comprises one or more SA additives selected from formulae SA-1 to SA-48, preferably from formulae SA-14 to SA-48, very preferably from formulae SA-20 to SA-34 and SA-44, and one or more RMs of formula I. Examples

[1045] The following examples illustrate the present application without limiting it. They show the preferred mixture concepts and the preferred used compounds and their respective concentrations and combinations with each other to the person skilled in the art. In addition, the examples illustrate the obtainable properties and combinations of properties.

[1046] In addition, the following abbreviations and notations are used:

[1047] V0 denotes the threshold voltage at 20°C, capacitive [V],

[1048] n e denotes the extraordinary refractive index at 20°C and 589 nm,

[1049] n o denotes the ordinary refractive index at 20°C and 589 nm,

[1050] An denotes the optical anisotropy at 20°C and 589 nm,

[1051] ε ⊥ denotes the dielectric constant perpendicular to the director at 20°C and 1 kHz,

[1052] ε || denotes the dielectric constant parallel to the director at 20°C and 1 kHz,

[1053] An denotes the optical anisotropy at 20°C and 589 nm,

[1054] cl.p., T(N, I) denotes clearing point [°C],

[1055] γ1 denotes rotational viscosity [mPa-s] at 20 °C,

[1056] K1 denotes elastic constant at 20 °C, "splay" deformation [pN],

[1057] K2 denotes elastic constant at 20 °C, "twist" deformation [pN],

[1058] K3 denotes elastic constant at 20 °C, "bend" deformation [pN].

[1059] All concentrations in this application are given in weight percent and relate to the respective whole mixture comprising all solid or liquid crystal components (without solvent) unless explicitly stated otherwise.

[1060] 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 given in degrees Celsius (°C) unless explicitly stated otherwise. M.p. means melting point, cl.p. = clearing point. Furthermore, C = liquid crystal phase, N = nematic phase, S = smectic phase and I = isotropic phase. The data between these symbols indicate the transition temperatures.

[1061] All physical properties are and have been determined according to "Merck Liquid Crystals, Physical Properties of Liquid Crystals" Status November 1997, Merck KGaA, Germany and apply to a temperature of 20 °C, and Δn is determined at 589 nm and Δε is determined at 1 kHz, unless explicitly stated otherwise in each case.

[1062] The term "threshold voltage" as used in this application relates to the capacitive threshold (V0), which is also called Freedericks threshold, unless explicitly stated otherwise. In embodiments, the optical threshold is also given for a relative contrast of 10% (V 10 ) as usual.

[1063] Unless explicitly stated otherwise, the process of polymerizing the polymerizable compounds in the 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.

[1064] Unless explicitly stated otherwise, the process of preparing the test cells and measuring their electro-optical and other properties is carried out by the methods described below or analogous methods.

[1065] The display for measuring the capacitive threshold voltage consists of two plane-parallel glass outer plates spaced by 25 pm, each having an electrode layer on the inner side and an unrubbed polyimide alignment layer on top, which leads to a homeotropic edge alignment of the liquid crystal molecules.

[1066] The PSVA display or PSVA test cell for measuring the tilt angle consists of two plane-parallel glass outer plates spaced by 4 pm, each having an electrode layer on the inner side and a polyimide alignment layer on top, where the two polyimide layers are rubbed anti-parallel to each other and lead to a homeotropic edge alignment of the liquid crystal molecules. A SAVA display or test cell has the same structure, but where one or both polyimide layers are omitted.

[1067] The polymerizable compounds are polymerized in the display or test cell by irradiation with UV light of defined intensity for a predefined time, while a voltage is applied to the display (typically 10 to 30 V AC, 1 kHz). In the examples, unless otherwise stated, a metal halide lamp and an intensity of 100 mW / cm2 2 are used for polymerization. The intensity is measured using a standard meter (high-end Hoenle UV-meter with UV sensor).

[1068] The Mueller Matrix Polarimeter "AxoScan" from Axometrics is used to determine the tilt angle. Here a low value (i.e. a large deviation from the 90° angle) corresponds to a large tilt.

[1069] The term "tilt angle" means the angle between the LC director and the substrate, and "LC director" means the preferred direction of orientation of the optical main axis of the LC molecules in a layer of LC molecules with uniform orientation, in the case of rod-like, uniaxial, positively birefringent LC molecules, corresponding to their molecular long axis, unless otherwise stated.

[1070] Example 1

[1071] Compound 1 was prepared as follows:

[1072]

[1073]

[1074] Melting point: 102 °C

[1075] Example 2

[1076] Compound 2 was prepared in analogy to the method of Example 1.

[1077]

[1078] Example 3

[1079] Compound 3 was prepared as follows

[1080]

[1081] a) Synthesis of Bromide A

[1082]

[1083] Dissolve 20.00 g (107.00 mmol) [1,1'-biphenyl]-4,4'-diol] in dichloromethane (1100 mL) and cool to 5 °C (suspension). Add 11.00 mL (214.82 mmol) Br2 (dissolved in 200 mL dichloromethane (DCM)) dropwise over 45 min and stir at 5 °C for an additional 4 hr. Treat the reaction mixture with NaHSO3 and separate the layers. Extract the aqueous layer with DCM and wash the combined organic layers with brine, dry over NaSO4, filter and evaporate under vacuum. Purify the crude product via column filtration with DCM and combine and evaporate the product fractions to yield the product as a colorless solid.

[1084] MS TOF-MS EI+ 343.892

[1085] 1 H NMR (500 MHz, DMSO) δ 10.31 (s, 2H), 7.70 (d, J = 2.2 Hz, 2H), 7.42 (dd, J = 8.4, 2.3 Hz, 2H), 6.99 (d, J = 8.4 Hz, 2H).

[1086] b) Synthesis of Bisphenol B

[1087]

[1088] Dissolve 12.86 g (93.02 mmol) K2CO3 in 41.9 mL water, add 8.00 g (23.00 mmol) bromide B, 5.73 g (51.00 mmol) (furan-2-yl)boronic acid and 94.2 mL THF. Add 638.88 mg (0.698 mmol Pd2(dba)3 and 526.64 mg (1.40 mmol) CataCXium A and reflux the reaction mixture for 16 hr. Cool the mixture to room temperature (RT), add MTB-ether and adjust the pH = 1 with a HCI solution. Separate the organic layer and extract the aqueous layer with MTB-ether. Wash the combined organic layers with brine, dry over Na2SO4, filter and evaporate under vacuum. Purify the crude product via column chromatography (330 g Si column, 30 pm) CombiFlash with DCM and MTB-ether to yield the product as a yellow solid.

[1089] MS TOF-MS EI+ 318.098

[1090] 1 H NMR (500 MHz, DMSO) d 10.19 (s, 2H), 7.88 (d, J = 2.4 Hz, 2H), 7.75 (d, J = 1.7 Hz, 2H), 7.39 (dd, J = 8.4, 2.4 Hz, 2H), 7.08 - 6.88 (m, 4H), 6.60 (dd, J = 3.4, 1.8 Hz, 2H).

[1091] c) Synthesis of compound 3

[1092]

[1093] Dissolve 7.40 g (23.00 mmol) diol 1, 5.92 mL (69.74 mmol) methacrylic acid (stabilized with hydroquinone monomethyl ether) and 4-(dimethylamino)-pyridine (DMAP) in 178.14 mL DCM (suspension) and cool to 4°C. Add 12.72 mL (69.74 mmol) 1 -(3-dimethylaminopropyl)-3-ethylcarbodiimide (EDC) dropwise (suspension turns into solution) and stir at room temperature for 2 hr. Cool the reaction mixture to 7°C and carefully quench the remaining EDC with oxalic acid. Filter the reaction mixture over 300 g silica gel (63-200 pm) and combine the product fractions and evaporate under vacuum. Crystallize the reaction product with acetone at 5°C to yield the product as an orange solid.

[1094] APCI-MS = 455.14837

[1095] 1H NMR (500 MHz, CDC13) δ 8.13 (d, J = 2.2 Hz, 2H), 7.58 (dd, J = 8.4, 2.3 Hz, 2H), 7.53 (d, J = 1.7 Hz, 2H), 7.25 (d, J = 8.3 Hz, 2H), 6.73 (d, J = 3.4 Hz, 2H), 6.58 - 6.41 (m, 4H), 5.89 (t, J = 1.6 Hz, 2H), 2.15 (d, J = 1.1 Hz, 6H).

[1096] Example 4

[1097] Compound 4 was prepared as follows

[1098]

[1099] a) Synthesis of Chloride A

[1100]

[1101] Dissolve 200.00 g (1.447 mol) K2CO3 in 600.00 mL water, add 75.00 g (358.00 mmol) 4-bromo-2-chlorophenol and 50.00 g (363.00 mmol) 4-hydroxyphenyl-boronic acid and 1000 mL THF. Add 5.50 g (14.573 mmol) CataCXium A and 6.60 g (7.21 mmol) Pd2dba3 and reflux the reaction mixture for 16 hr. After cooling to RT, add MTB-ether and water and separate the layers. Extract the aqueous layer with MTB-ether and dry the combined organic layers over Na2SO4, filter and evaporate under vacuum. Purify the product by column filtration with DCM / MTB-ether (95:5 and 9:1) and crystallization with toluene to yield the product as a solid material.

[1102] 1 H NMR (500 MHz, DMSO) δ 10.11 (s, 1H), 9.47 (s, 1H), 7.51 (d, J = 2.3 Hz, 1H), 7.44 - 7.38 (m, 2H), 7.35 (dd, J = 8.4, 2.3 Hz, 1H), 7.00 (d, J = 8.4 Hz, 1H), 6.89 - 6.70 (m, 2H).

[1103] b) Synthesis of Bisphenol B

[1104]

[1105] Dissolve 5.00 g (22.59 mmol) of Bisphenol A, 4.00 g (34.68 mmol) of furan-3- boronic acid in 75 mL of THF and add 10.00 g (43.42 mmol) of K3PO4*H2O in 25 mL of water. Add 350.00 mg (0.927 mmol) of CataCXium A and 420.00 mg (0.459 mmol) of Pd2dba3 and reflux the reaction mixture for 18 hr. Cool the reaction mixture to RT, add ethyl acetate (EE) and water, separate the organic layer and extract the aqueous layer with EE. Wash the combined organic layers with brine and dry with Na2SO4, filter and evaporate under vacuum to yield a dark oil. Purify the crude product by crystallization with toluene at room temperature to yield the product as a beige solid.

[1106] TOF-MS-EI+ = 252.079

[1107] H NMR (500 MHz, DMSO) δ 9.94 (s, 1H), 9.39 (s, 1H), 8.26-8.10 (m, 1H), 7.78-7.57 (m, 2H), 7.48-7.42 (m, 2H), 7.29 (dd, J = 8.4, 2.4 Hz, 1H), 7.13 (d, J = 1.9 Hz, 1H), 6.96 (d, J = 8.3 Hz, 1H), 6.85-6.76 (m, 2H).

[1108] c) Synthesis of compound 4

[1109]

[1110] Dissolve 3.20 g (11.82 mmol) of diol B, 300.00 mg (2.46 mmol) of DMAP and 3.02 mL (35.47 mmol) of methacrylic acid (stabilized with hydroquinone monomethyl ether) in 100 mL of DCM (suspension) and cool to 4°C. Add 6.47 mL (35.47 mmol) of l-(3-dimethylaminopropyl)-3- ethylcarbodiimide (EDC) dropwise (after 15 min. the suspension becomes a solution) and stir at room temperature for 2 hr. Cool the reaction mixture to 7°C and carefully quench the remaining EDC with oxalic acid. Purify the crude product via column chromatography with DCM and crystallize the collected evaporated product fractions with toluene to yield the product as a beige solid.

[1111] FTMS+ APCI = 389.13773

[1112] 1H NMR (500 MHz, CDC13) δ 7.77 - 7.72 (m, 1H), 7.71 (d, J = 2.2 Hz, 1H), 7.66 - 7.59 (m, 2H), 7.55 - 7.45 (m, 2H), 7.27 - 7.18 (m, 3H), 6.72 (d, J = 1.8 Hz, 1H), 6.41 (d, J = 4.3 Hz, 2H), 5.82 (dt, J = 16.5, 1.6 Hz, 2H), 2.15 - 2.02 (m, 6H).

[1113] Use Example A

[1114] The nematic LC host mixture N1 was formulated as follows:

[1115]

[1116]

[1117] Polymerisable mixture

[1118] Polymerisable mixtures P1 to P3 were prepared by adding the polymerisable compounds of Example 1 and / or 2 and the SA additive SA-23 to the nematic LC host mixture N1.

[1119] The polymerisable mixture PC1 was prepared by adding the polymerisable compound C1 according to the prior art and the SA additive SA-23 to the nematic LC host mixture N1.

[1120]

[1121] Test cell

[1122] Each polymerisable mixture was filled into a SA-VA test cell and exposed to UV light for 2 h.

[1123] The reflectivity of the test cells was measured with a spectrophotometer CM-700d (Konica Minolta) before and after UV exposure.

[1124] The polymerisable mixture compositions and reflectivity are shown in Table 1.

[1125] Table 1 - Polymerisable mixture compositions and reflectivity

[1126]

[1127]

[1128] It can be seen that the mixtures P1 to P3 according to the application containing the polymerisable compounds 1 or 2 of formula I show a reduced reflectivity after UV treatment compared to the mixture PC1 containing the polymerisable compound C1 according to the prior art.

[1129] Thus, the polymerisable mixtures P1 to P3 are especially suitable for use in polymer-stabilised SA-VA displays.

Claims

1. A compound of formula I, characterized in that... which is selected from the following subformulae wherein each group, independently of each other and on each occurrence, has the following meanings: Ar independently of each other denotes benzene, furan or thiophene, which is optionally substituted by one or more groups L; L is selected from F, CI, Br, CN, alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy each having 1 to 6 C atoms, wherein one or more H atoms are optionally replaced by F or CI; b1 is 0, 1 or 2; P independently of each other denotes acrylic or methacrylic ester; Sp is a single bond; with the proviso that if the compound contains two groups Ar and no group L, Ar is different from unsubstituted benzene.

2. The compound according to claim 1, characterized in that which is selected from the following subformulae 3. The compound according to claim 1, wherein Ar denotes unsubstituted benzene, furan or thiophene.

4. The compound according to claim 1, wherein Ar denotes unsubstituted benzene.

5. A liquid-crystalline (LC) medium comprising one or more compounds of formula I as defined in any of claims 1 to 4.

6. LC medium according to claim 5, characterised in that which contains a self-alignment (SA) additive.

7. LC medium according to claim 5, characterised in that which additionally comprises one or more further components or additives selected from the group consisting of co-monomers, chiral dopants, polymerization initiators, inhibitors, stabilizers, surfactants, wetting agents, lubricants, dispersants, hydrophobes, adhesion agents, flow improvers, defoamers, de-gassing agents, diluents, dyes, pigments and nanoparticles.

8. LC medium according to claim 7, characterised in that The diluents include reactive diluents.

9. LC medium according to any of claims 5 to 8, characterized in that The compounds of formula I are polymerized.

10. A process for the preparation of an LC medium according to any of claims 5 to 9, comprising the following steps: mixing one or more mesogenic or liquid-crystalline compounds with one or more compounds of formula I as defined in any of claims 1 to 4, and optionally further liquid-crystalline compounds and / or additives, and optionally polymerizing the compounds of formula I.

11. An LC display comprising one or more compounds of formula I as defined in any of claims 1 to 4 or comprising an LC medium as defined in any of claims 5 to 9.

12. The LC display according to claim 11, which is a PSA or a polymer stabilized SA display.

13. The LC display according to claim 12, which is a PS-VA, PS-OCB, PS-IPS, PS-FFS, PS-UB-FFS, PS-posi-VA, PS-TN, polymer stabilized SA-VA or polymer stabilized SA-HB-FFS display.

14. LC display according to claim 12 or 13, characterised in that which comprises two substrates, at least one of which is light-transmitting; one electrode provided on each substrate or two electrodes provided on only one of the substrates, and a layer of an LC medium located between the substrates, which LC medium comprises one or more compounds of formula I as defined in claim 9, wherein the polymerizable compounds are polymerized between the substrates of the display.

15. A process for producing an LC display according to claim 14, which comprises the steps of providing an LC medium comprising one or more compounds of formula I as defined in claim 5 between the substrates of the display and polymerizing the compounds.

16. The compound according to any one of claims 1 to 5, wherein each group P or each methacrylate group is replaced by OH, respectively.

17. A process for the preparation of a compound of formula I according to any one of claims 1 to 4, by esterification of a compound according to claim 16 with the corresponding acid, acid derivative or halogenated compound containing the group P in the presence of a dehydrating agent.

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