Liquid crystal medium comprising polymerizable compounds

Abstract

The present invention relates to a liquid crystal (LC) medium comprising several polymerizable compounds and an additive for homeotropic alignment as further defined in the description or claims. The medium is suitable for use in LC displays, in particular LC displays of the polymer-stabilized alignment type, when one or both conventional alignment layers are omitted.

Description

Technical Field

[0001] The present invention relates to a liquid crystal (LC) medium, as further defined in the description or claims, comprising several polymerizable compounds and an additive for homeotropic alignment. The medium is suitable for use in LC displays, in particular LC displays of the polymer-stabilized alignment type, when one or both conventional alignment layers are omitted. Background Art

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

[0003] Also known are so-called VA (vertically aligned) displays, which offer even wider viewing angles. The LC cell of a VA display contains a layer of LC medium between two transparent electrodes, where the LC medium typically has a negative dielectric anisotropy. In the off state, the molecules of the LC layer are aligned perpendicular to the electrode surfaces (homeotropically) or have a tilted homeotropic alignment. When a voltage is applied to the two electrodes, the LC molecules realign parallel to the electrode surfaces.

[0004] Also known are so-called IPS ("In-Plane Switching") displays, which comprise an LC layer between two substrates. Two electrodes are arranged on only one of the two substrates and preferably have an intermeshing comb-like structure. When a voltage is applied to the electrodes, an electric field with a significant component parallel to the LC layer is generated between them. This results in a realignment of the LC molecules within the plane of the layer.

[0005] Furthermore, so-called FFS ("fringe field switching") displays have been reported (see, inter alia, SH Jung et al., Jpn. J. Appl. Phys., Vol. 43, No. 3, 2004, 1028). These comprise two electrodes on the same substrate, one of which is structured in a comb-like manner and the other unstructured. This results in strong so-called "fringe fields," i.e., a strong electric field near the electrode edges and an electric field with a strong vertical component and a strong horizontal component throughout the liquid crystal cell. FFS displays have a low viewing angle dependence of the contrast. FFS displays typically contain an LC medium with positive dielectric anisotropy and an alignment layer, typically a polyimide alignment layer, which provides for planar alignment of the molecules of the LC medium.

[0006] FFS displays can be operated as active matrix or passive matrix displays. In the case of active matrix displays, the individual pixels are typically addressed by integrated non-linear active elements such as transistors (e.g., thin film transistors or "TFTs"), while in the case of passive matrix displays, the individual pixels are typically addressed according to multiplexing methods as known in the art.

[0007] In addition, FFS displays have been disclosed (see SH Lee et al., Appl. Phys. Lett. 73 (20), 1998, 2882-2883 and SH Lee et al., Liquid Crystals 39 (9), 2012, 1141-1148) which have an electrode design and layer thickness similar to those of FFS displays, but include a layer of an LC medium having a negative dielectric anisotropy rather than a layer of an LC medium having a positive dielectric anisotropy. Compared to LC media having a positive dielectric anisotropy, LC media having a negative dielectric anisotropy exhibit a more favorable director orientation, with a less tilted and more twisted orientation, with the result that these displays have a higher transmittance. The display also includes an alignment layer, typically a polyimide provided on at least one substrate, which contacts the LC medium and induces a planar alignment of the LC molecules of the LC medium. These displays are also referred to as "ultra-bright FFS (UB-FFS)" mode displays. These displays require an LC medium having high reliability.

[0008] The term "reliability" as used hereinafter refers to the quality of a display's performance over time and under various stresses, such as light load, temperature, humidity, and voltage, and includes display effects such as image sticking (area and line image sticking), color variations (mura), and non-uniformities (yogore), which are known to those skilled in the art of LC displays. As a standard parameter for classifying reliability, the voltage holding ratio (VHR) value is often used, which is a measure of the ability to maintain a constant voltage in a tested display. Among other factors, a high VHR is a prerequisite for high reliability of LC media.

[0009] In newer types of VA displays, the uniform alignment of the LC molecules is confined to a number of relatively small domains within the LC cell. Disclinations, also known as tilted domains, can exist between these domains. VA displays with tilted domains offer greater contrast and viewing angle independence of greyscale (grey shades) compared to conventional VA displays. Furthermore, this type of display is easier to produce because additional electrode surface treatment (e.g., by rubbing) is no longer required to uniformly align the molecules in the on state. Instead, the preferred orientation of the tilt angle, or pretilt angle, is controlled by special electrode design.

[0010] In so-called MVA ("Multi-Domain Vertical Alignment") displays, this is usually achieved by electrodes having protrusions that cause local pretilt. As a result, when a voltage is applied, the LC molecules are aligned parallel to the electrode surface in different directions in different, defined cell areas. This achieves "controlled" switching and prevents the formation of disruptive disclination lines. Although this arrangement improves the viewing angle of the display, it leads to a reduction in its light transmittance. A further development of the MVA uses protrusions on only one electrode side, while the opposite electrode has a slit, which improves the light transmittance. This slit electrode generates an inhomogeneous electric field in the LC cell when a voltage is applied, which means that controlled switching is still achieved. To further improve the light transmittance, the spacing between the slit and the protrusion can be increased, but this in turn leads to a longer response time. In so-called PVA ("patterned VA"), the protrusions become completely superfluous, since the two electrodes are structured on opposite sides by slits, which leads to increased contrast and improved light transmission, but 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 and to improve its contrast and brightness (transmittance).

[0011] Another development is the so-called PS ("polymer-stabilized") or PSA ("polymer-stabilized alignment") display, for which the term "polymer-stabilized" is occasionally also used. In these, small amounts (e.g., 0.3% by weight, typically <1% by weight) of one or more polymerizable compounds, preferably polymerizable monomeric compounds, are added to the LC medium and, after the LC medium has been filled into the display, are polymerized or crosslinked in situ (usually by UV photopolymerization), optionally while a voltage is applied to the display's electrodes. The polymerization takes place at a temperature at which the LC medium exhibits a liquid-crystalline phase, typically room temperature. The addition of polymerizable mesogens or liquid-crystalline compounds (also called reactive mesogens or "RMs") to the LC mixture has proven particularly suitable.

[0012] Unless otherwise stated, the term "PSA" is used hereinafter when referring generally to displays of the polymer stabilised alignment type, and "PS" is used when referring to specific display modes (such as PS-VA, PS-TN etc.).

[0013] Furthermore, unless otherwise stated, the term "RM" is used hereinafter when referring to polymerisable mesogenic or liquid crystal compounds.

[0014] At the same time, the PS(A) principle is being used in various conventional LC display modes. For example, PS-VA, PS-OCB, PS-IPS, PS-FFS, PS-UB-FFS, and PS-TN displays are known. In the case of PS-VA and PS-OCB displays, polymerization of the RMs preferably occurs under an applied voltage, while in the case of PS-IPS displays, it occurs with or without, preferably without, an applied voltage. As can be verified in test cells, the PS(A) method leads to pretilt in the cell. In the case of PS-OCB displays, for example, the curved structure can be stabilized, so that the offset voltage is unnecessary or can be reduced. In the case of PS-VA displays, this pretilt has a positive effect on the response time. For PS-VA displays, standard MVA or PVA pixel and electrode layouts can be used. However, it is also possible to manage, for example, only one structured electrode side without protrusions, which significantly simplifies production while simultaneously resulting in very good contrast and very good light transmittance.

[0015] 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 SH Kim, L.-C-Chien, Jpn. J. Appl. Phys. 43, 2004, 7643-7647.

[0016] Beneath the layer formed of phase-separated and polymerized RMs inducing the above-mentioned pretilt angle, conventional PSA displays typically comprise an alignment layer, for example of polyimide, which provides an initial alignment of the LC molecules prior to the polymer stabilization step.

[0017] Rubbed polyimide layers have long been used as alignment layers. However, rubbing methods cause various problems, such as color difference, contamination, electrostatic discharge issues, and residue. The effort and cost of producing such polyimide layers are generally relatively high. Therefore, instead of rubbing polyimide layers, it has been proposed to use polyimide layers prepared by photoalignment or by self-alignment by adding suitable additives to the LC medium.

[0018] Furthermore, it has been observed that unfavorable interactions of the polyimide alignment layer with certain compounds of the LC medium often lead to a reduction in the resistance of the display. Consequently, the number of suitable and usable LC compounds is significantly reduced, at the expense of the display parameters that are intended to be improved by using such LC compounds (e.g., viewing angle dependence, contrast, and response time). Therefore, it is desirable to omit the polyimide alignment layer.

[0019] For some display modes, this is achieved by adding self-aligning agents or additives to the LC medium, which induce the desired homeotropic (vertical) alignment in situ via a self-assembly mechanism. Thus, alignment layers on one or both substrates can be omitted. These display modes are also referred to as "self-aligning" or "self-aligned" (SA) modes.

[0020] In SA mode displays, small amounts (typically 0.1% to 2.5%) of self-aligning additives are added to the LC medium. Suitable self-aligning additives are, for example, organic core groups (MES) and one or more polar anchoring groups (R a ) compounds that can interact with the substrate surface, aligning the additive on the substrate surface and also inducing the desired alignment in the LC molecules. The organic core group preferably comprises two rings or ring systems, which are usually substituted. Preferred self-aligning additives include, for example, mesogenic groups (MES) and linear or branched side chains terminated by one or more polar anchoring groups, such as hydroxyl, carboxyl, amino, or thiol groups. The self-aligning additive may also contain one or more polymerizable groups that can be polymerized under conditions similar to those used for RMs in PSA methods.

[0021]

[0022] Schematic. Including connection to the polymerizable group P and the anchoring group R a Several P groups can be used. As a variant, one or more of them can be attached to an anchoring group instead of a mesogenic core group.

[0023] SA-VA displays have been disclosed to date. Suitable self-aligning additives for inducing homeotropic alignment, particularly for use in SA-VA mode displays, are disclosed in, for example, US 2013 / 0182202 A1, US 2014 / 0838581 A1, US 2015 / 0166890 A1, and US 2015 / 0252265 A1.

[0024] The self-aligning mode can be used in combination with the PSA mode.The LC medium for displays in this combined mode therefore contains one or more RMs and one or more self-aligning additives.

[0025] Similar to the conventional LC displays described above, PSA displays can be operated as active matrix or passive matrix displays. In the case of active matrix displays, the individual pixels are typically addressed by integrated non-linear active elements such as transistors (e.g., thin film transistors "TFTs"), while in the case of passive matrix displays, the addressing is typically performed by multiplexing methods as known in the art.

[0026] In particular, for monitors and, in particular, TV applications, there is a growing demand for optimization of the response time, contrast, brightness (and therefore also transmittance) of liquid crystal displays. The PSA method offers key advantages here. In particular, in the case of PS-VA, PS-IPS, PS-FFS, and PS-positive-VA displays, a reduction in the response time associated with the pretilt, which can be measured in a test cell, can be achieved without significantly adversely affecting other parameters.

[0027] The prior art has already proposed the use of optionally fluorinated biphenyl diacrylate or diphenyl dimethacrylate as RM in PSA displays.

[0028] However, the problem arises that not all combinations of an LC mixture and one or more RMs are suitable for PSA displays, for example because insufficient or no tilt is established, or because the VHR is insufficient for TFT display applications. Furthermore, it has been found that the LC mixtures and RMs known from the prior art still have some disadvantages when used in PSA displays. Consequently, not every known RM that is soluble in an LC mixture is suitable for use in PSA displays. Furthermore, apart from direct measurements of the pretilt in PSA displays, it is often difficult to find suitable selection criteria for the RMs. If polymerization is desired with the aid of UV light without the addition of a photoinitiator (which can be advantageous for certain applications), the choice of suitable RMs becomes even smaller.

[0029] Self-aligning additives for homeotropic alignment often have additional polymerizable groups.Since the behavior of a RM may be different in the presence of a self-aligning additive, the combination of a polymerizable RM and a polymerizable self-aligning additive appears to have certain effects of its own.

[0030] Furthermore, the selected LC host mixture / RM combination should have the lowest possible rotational viscosity and the best possible electrical properties. In particular, it should have the highest possible VHR. In PSA displays, a high VHR after irradiation with UV light is particularly desirable, as UV exposure is an essential part of the display production process and also occurs as normal light exposure during operation of the finished display.

[0031] In particular, it is desirable to make available novel materials for PSA displays that generate suitably low tilt angles. Preferred materials are those that, during polymerization, generate lower tilt angles for the same exposure time than previously known materials and / or that, by using them, achieve the desired results even after shorter exposure times. This can shorten the production time ("takt time") of displays and reduce the costs of the production process. However, in combination with other polymerizable components (e.g., self-aligning additives for homeotropic alignment), the tilt angle can also become too low. In this case, even more adjustments to the tilt-generating behavior may be necessary, if the LC medium so requires.

[0032] Another problem in the production of PSA displays is the presence or removal of residual amounts of unpolymerized RMs, particularly after the polymerization step used to create the pretilt angle in the display. For example, such unreacted RMs can adversely affect the properties of the display by, for example, polymerizing in an uncontrolled manner after the display is manufactured or during operation.

[0033] Therefore, PSA displays known from the prior art often exhibit the undesirable effect of so-called "image sticking" or "image burning", i.e. the image produced by the brief addressing of individual pixels in an LC display remains visible even after the electric field in these pixels has been switched off or after other pixels have been addressed.

[0034] This "image sticking" can occur if LC host mixtures with a low VHR are used. UV components of sunlight or backlighting can trigger undesirable decomposition reactions in LC molecules and thus the production of ionic or free-radical impurities. These can accumulate, particularly at electrodes or alignment layers, where they can reduce the effective applied voltage. This effect can also be observed in conventional LC displays without polymer components.

[0035] Furthermore, an additional "image sticking" effect caused by the presence of unpolymerized RMs is often observed in PSA displays. Uncontrolled polymerization of residual RMs is triggered by UV light from the ambient environment or the backlight. This changes the tilt angle in the switched display area after multiple addressing cycles. Consequently, the transmittance can vary in the switched area, while remaining unchanged in the unswitched area.

[0036] Therefore, it is desirable to achieve the most complete polymerization of RMs during PSA display production and to eliminate or minimize the presence of unpolymerized RMs in the display. Therefore, there is a need for RM and LC mixtures that enable or support highly efficient and complete RM polymerization. Furthermore, controlled reaction of residual RM levels is desirable. This would be further simplified if RMs could polymerize faster and more efficiently than previously known materials.

[0037] Self-aligning modes using self-aligning additives for homeotropic alignment allow for the elimination of one or two conventional alignment layers. However, the passivation and optical properties of conventional alignment layers are also altered. For simplicity, it is desirable to have self-aligning PSA systems with similar behavior on electrodes, such as strong passivation and a similar refractive index (n). However, current 0.3% RMs generally do not exhibit the same properties as polyimides.

[0038] However, rapid polymerization is often associated with a high sensitivity to UV radiation. Since UV radiation is also used to harden the panel sealant material at the panel edges, care must be taken to prevent premature polymerization, especially near the panel sealant. In this case, small bright spots or poor alignment in the dark state may occur. It is desirable to have a process-stable LC medium that can absorb a reasonable level of UV light from the panel sealing operation. Furthermore, the LC medium must be insensitive to trace amounts of sealant material present as impurities near the panel edges.

[0039] Another issue observed in the operation of PSA displays is the stability of the pretilt angle. Thus, it has been observed that the pretilt angle (which is generated during the display's manufacturing process by polymerizing RMs as described above) does not remain constant, but rather deteriorates after the display is subjected to voltage stress during its operation. This can negatively impact display performance, for example by increasing black state transmittance and, therefore, reducing contrast.

[0040] Another problem to be addressed is that prior art RMs often have high melting points and exhibit only limited solubility in many currently common LC mixtures, and therefore often tend to spontaneously crystallize out of the mixture. Furthermore, the risk of spontaneous polymerization prevents the LC host mixture from being warmed to dissolve the polymerizable component, meaning that even at room temperature, the best possible solubility is necessary. Furthermore, there is a risk of segregation, for example when the LC medium is introduced into an LC display (chromatographic effects), which can significantly impair the homogeneity of the display. This is further exacerbated by the fact that the LC medium is typically introduced at low temperatures to reduce the risk of spontaneous polymerization (see above), which in turn has a negative impact on solubility.

[0041] 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 color shifts in the display, particularly when the LC media is filled into display cells manufactured using an on-discharge (ODF) method. This phenomenon is also known as "ODF color shift." Therefore, there is a need to provide LC media that result in minimal ODF color shifts.

[0042] Another problem observed in the prior art is that LC media used in PSA displays, including but not limited to PSA-type displays, often exhibit high viscosity and, consequently, long switching times. To reduce the viscosity and switching times of LC media, the prior art has proposed the addition of LC compounds containing alkenyl groups. However, it has been observed that LC media containing alkenyl compounds often exhibit reduced reliability and stability, as well as a decrease in VHR, particularly after exposure to UV radiation. This is a considerable disadvantage, particularly for use in PSA displays, since photopolymerization of RMs in PSA displays is typically carried out by exposure to UV radiation, which can lead to a decrease in the VHR of the LC medium.

[0043] There is therefore still a great need for PSA displays and for LC media and polymerizable compounds for use in such displays which do not exhibit the disadvantages mentioned above or exhibit these disadvantages only to a small extent and have improved properties.

[0044] In particular, there is a great need for PSA displays and LC media and polymerizable compounds for such PSA displays that enable high specific resistance over a wide operating temperature range, short response times even at low temperatures, low threshold voltages, low pretilt angles, a large number of grayscale shades, high contrast, and wide viewing angles, as well as high reliability and a high value of VHR after UV exposure, and, in the case of polymerizable compounds, low melting points and high solubility in LC host mixtures. In PSA displays for mobile applications, there is a particular need for usable LC media that exhibit low threshold voltages and high birefringence.

[0045] Several types of RMs have been reported in the prior art for use in PSA displays, such as RMs having a biphenyl or terphenyl mesogenic core and two or three polymerizable acrylate or methacrylate groups attached thereto. Biphenyl RMs have been shown to exhibit limited polymerization speeds but good reliability parameters, such as high VHR or tilt stability, while terphenyl RMs have been shown to exhibit fast polymerization speeds but limited reliability parameters. Therefore, there is a need for available RMs that exhibit both fast polymerization speeds and good reliability parameters.

[0046] It was an object of the present invention to provide novel suitable materials, in particular RMs for PSA displays and LC media comprising the same, which do not have the disadvantages indicated above or have the disadvantages indicated above to a lesser extent.

[0047] In particular, the present invention aims to provide RMs for PSA displays, preferably self-alignment mode PSA displays, and LC media containing the same, which achieve very high specific resistance values, high VHR values, high reliability, low threshold voltage, short response time, high birefringence, show good UV absorption, especially at longer wavelengths, enable rapid and complete polymerization of the RM, enable the generation of a suitable tilt angle, preferably as quickly as possible, achieve high stability of the pretilt even after a long time and / or after UV exposure, reduce or prevent the occurrence of "bright spots", "image sticking" and "ODF color shift" in the display, and in the case of RMs polymerize as quickly and completely as possible, and show high solubility in the LC medium typically used as a host mixture in PSA displays.

[0048] Another object of the present invention is to provide RMs for self-aligned mode PSA displays which exhibit both a fast polymerization speed and good reliability parameters, such as high VHR or tilt stability.

[0049] Another object of the present invention is to provide new RMs, in particular for use in optical, electrooptical and electronic applications; and suitable processes and intermediates for their preparation.

[0050] These objects have been achieved according to the invention by the materials and methods as described in this application. In particular, it has surprisingly been found that the use of a combination of RMs of formulae I and II as described below with a self-aligning additive of formula III makes it possible to achieve the advantageous effects mentioned above.

[0051] Surprisingly, it has been found that the use of combinations of these RMs and LC media comprising them in PSA displays, in particular at longer UV wavelengths in the range of 300-380 nm and especially greater than 320 nm, even without the addition of a photoinitiator, promotes a fast and complete UV photopolymerization reaction, leading to the rapid generation of a suitable and stable pretilt angle, avoiding the appearance of bright spots; reduces image sticking and ODF color differences in the display, results in high reliability and high VHR values ​​after UV photopolymerization, and enables fast response times, low threshold voltages and high birefringence to be achieved.

[0052] PSA displays are typically cured in a first and second curing step. Although the first step is performed at approximately 10 2 s cures the vast majority of the polymerizable components, but a second, longer step achieves complete consumption of the residual polymerizable material (approximately 10 3 s). Surprisingly, the LC media according to the invention make it possible, in particular for the second curing step, to use light in the UV-B range (365 nm) instead of the conventional shorter UV light (313 nm). By using different lamps, considerable investment and energy savings can be achieved.

[0053] Furthermore, the RMs according to the present invention have a low melting point, good solubility, and a low tendency to crystallize in a wide range of LC media for PSA applications, especially in commercially available LC host mixtures. Furthermore, they exhibit good absorption at longer UV wavelengths, particularly in the range of 300-380 nm, and enable rapid and complete polymerization, with little residual, unreacted RM in the cell.

[0054] Likewise, it was surprisingly found that the combination of RMs according to the present invention combines fast polymerization speeds similar to those of terphenyl RMs with good reliability parameters similar to those of biphenyl RMs. This results in superior overall performance compared to prior art RMs.

[0055] WO 2009 / 030322 A1 discloses polymerizable compounds based on biphenyl structures having two or three acrylate or methacrylate groups, but does not mention self-aligning additives for vertical alignment, nor does it address the bright spot problem addressed by the present invention. Summary of the Invention

[0056] The present invention relates to an LC medium comprising:

[0057] a polymerizable component A) comprising, preferably consisting of, one or more polymerizable compounds,

[0058] wherein at least one is a compound of formula I,

[0059] wherein at least the second is a compound of formula II, and

[0060] at least a third is a polymerizable self-aligning additive for homeotropic alignment of formula III, and

[0061] - Liquid-crystalline component B), hereinafter also referred to as "LC host mixture", which comprises, preferably consists of, one or more mesogenic or liquid-crystalline compounds.

[0062] The various definitions are:

[0063]

[0064] where the individual radicals, independently of one another and identically or differently on each occurrence, have the following meanings:

[0065] P is a polymerizable group,

[0066] Sp is a spacer group or a single bond,

[0067] R L is -CH3, -C2H5 or -CH2CH2CH3,

[0068] r is independently 0, 1 or 2

[0069] s is 0 or 1, and

[0070] L 1 , L 2 , L 3 is independently F, Cl or a linear, branched or cyclic alkyl group having 1 to 5 C atoms, wherein one or more non-adjacent CH2- groups are optionally replaced by -O-, -S-, -CO-, -CO-O-, -O-CO- or -O-CO-O- in such a way that the O and / or S atoms are not directly connected to each other, and wherein one or more H atoms are each optionally replaced by F or Cl,

[0071]

[0072] where the individual radicals, independently of one another and identically or differently on each occurrence, have the following meanings:

[0073] P is a polymerizable group,

[0074] Sp is a spacer group or a single bond,

[0075] r is independently 0, 1 or 2

[0076] s is 0 or 1, and

[0077] L 1 , L 2 is independently F, Cl or a linear, branched or cyclic alkyl group having 1 to 5 C atoms, wherein one or more non-adjacent CH2- groups are optionally replaced by -O-, -S-, -CO-, -CO-O-, -O-CO- or -O-CO-O- in such a way that the O and / or S atoms are not directly connected to each other, and wherein one or more H atoms are each optionally replaced by F or Cl,

[0078] MES-R a III

[0079] in

[0080] MES is a rod-shaped mesogenic group comprising two or more rings which are directly or indirectly attached to one another or fused to one another, wherein the rings are optionally substituted and which are optionally further substituted by one or more polymerizable groups which are attached directly to the MES or via a spacer, and

[0081] R a is a polar anchoring group located at the end of the rod-shaped mesogen group MES, wherein the group R aContains at least one carbon atom and at least one group selected from -OH, -SH, -COOH, -CHO or a primary or secondary amine function, and is optionally connected directly or via a spacer to R by one or two a The attached polymerizable group is substituted,

[0082] At least one of MES or R a is substituted with at least one polymerizable group, directly or through a spacer.

[0083] The liquid-crystalline component B) of the LC media according to the invention is also referred to hereinafter as "LC host mixture" and preferably comprises one or more, preferably at least two, mesogenic or LC compounds selected from non-polymerizable low molecular weight compounds (ie non-polymeric compounds).

[0084] The invention furthermore relates to an LC medium or an LC display as described above, in which the compounds of the formulae I, II and III or the polymerisable compounds of component A) are polymerised.

[0085] The present invention also relates to a process for preparing an LC medium as described above and below, comprising the step of mixing one or more mesogens or LC compounds, or an LC host mixture or LC component B), as described above and below, with one or more compounds of each of the formulae I, II and III, and optionally further LC compounds and / or additives.

[0086] The present invention also relates to the use of the LC medium according to the invention in PSA displays, in particular in PSA displays containing an LC medium, for generating a tilt angle in the LC medium by in situ polymerization of one or more compounds of the formulae I to III in the PSA display, preferably in an electric or magnetic field.

[0087] The present invention also relates to LC displays comprising the LC medium according to the invention, in particular PSA displays with homeotropic alignment, particularly preferably PS-VA, PS-UB-FFS or PS-positive-VA displays. Preferably, the present invention relates to LC displays comprising one or more compounds of each of the formulae I, II and III.

[0088] The present invention furthermore relates to the use of the LC media according to the invention in polymer-stabilized SA-VA displays and to polymer-stabilized SA-VA displays comprising the LC media according to the invention.

[0089] The invention furthermore relates to LC displays comprising polymers obtainable by polymerization of the LC media according to the invention, preferably PSA displays, very preferably PS-VA, PS-UB-FFS, PS-positive-VA or polymer-stabilized SA-VA displays.

[0090] The invention furthermore relates to an LC display of the PSA type comprising two substrates, at least one of which is transparent to light, electrodes provided on each substrate or two electrodes provided on only one of the substrates, and a layer of LC medium located between the substrates, the layer of LC medium comprising an LC medium as described above and below, wherein the polymerizable compound between the substrates of the display is polymerized.

[0091] The invention furthermore relates to a method for producing an LC display as described above and below, comprising the steps of filling or otherwise providing an LC medium according to the invention as described above and below between the substrates of the display, and polymerizing the polymerizable compound.

[0092] PSA displays according to the invention have two electrodes, preferably in the form of transparent layers, applied to one or both substrates. In some displays, such as PS-VA, PS-OCB, or polymer-stabilized SA-VA displays, one electrode is applied to each of the two substrates. In other displays, such as PS-positive-VA and PS-IPS, the two electrodes are applied to only one of the two substrates.

[0093] In a preferred embodiment, the polymerisable components are polymerised in the LC display while a voltage is applied to the electrodes of the display.

[0094] The polymerizable compounds of the polymerizable component are preferably polymerized by photopolymerization, very preferably by UV photopolymerization.

[0095] When used in homeotropically self-aligned PSA displays, the LC media according to the invention exhibit the following advantageous properties:

[0096] - suitable tilt generation within a certain process window,

[0097] - Fast polymerization with minimal residue of RM after UV treatment,

[0098] - Reduce the occurrence of bright spots,

[0099] -Suitable for UV treatment without initiator,

[0100] -High voltage holding rate after UV treatment,

[0101] - Good tilt stability,

[0102] -Sufficient heat stability,

[0103] -Sufficient low temperature stability against crystallization.

[0104] As used herein, the terms "active layer" and "switchable layer" refer to a layer in an electro-optical display, e.g. an LC display, comprising one or more molecules with structural and optical anisotropy (e.g. LC molecules), which molecules change their orientation when subjected to an external stimulus, such as an electric or magnetic field, which results in a change in the transmittance of the layer for polarized or unpolarized light.

[0105] As used herein, the terms "tilt" and "tilt angle" are understood to denote the tilted alignment of the LC molecules of an LC medium relative to the cell surface in an LC display (preferably a PSA display). The tilt angle here denotes the average angle (<90°) between the longitudinal molecular axis of the LC molecules (LC director) and the plane-parallel outer plates forming the LC cell. Low values ​​for the tilt angle (i.e., large deviations from a 90° angle) correspond to large tilts. A suitable method for measuring the tilt angle is given in the Examples. Unless otherwise stated, the tilt angle values ​​disclosed above and below relate to this measurement method.

[0106] As used herein, the terms "reactive mesogen" and "RM" are understood to mean a compound comprising a mesogenic or liquid crystal backbone and attached thereto one or more functional groups suitable for polymerization, and said functional groups are also referred to as "polymerizable groups" or "P".

[0107] Unless otherwise indicated, the term "polymerizable compound" as used herein is to be understood as a polymerizable monomeric compound.

[0108] As used herein, the term "low molecular weight compound" is understood to mean a compound that is monomeric and / or not prepared by polymerization, as opposed to a "polymeric compound" or "polymer."

[0109] As used herein, the term "non-polymerizable compound" is understood to mean a compound that does not comprise functional groups suitable for polymerization under the conditions typically applied to the polymerization of RMs.

[0110] As used herein, the term "mesogenic group" is known to those skilled in the art and is described in the literature and refers to a group that substantially contributes to the generation of liquid crystal (LC) phases in low molecular weight or polymeric substances due to the anisotropy of their attractive and repulsive interactions. A compound comprising a mesogenic group (mesogenic compound) does not necessarily have an LC phase itself. A mesogenic compound may also exhibit LC phase behavior only after mixing with other compounds and / or after polymerization. Typical mesogenic groups are, for example, rigid rod-shaped or disc-shaped units. Rod-shaped mesogens are also referred to as rod-shaped mesogens because they often form rod-shaped phases (e.g., nematic phases or smectic phases). In the present disclosure, mesogen preferably refers to rod-shaped mesogens. Terms and definitions used in connection with mesogens 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.

[0111] As used herein, the term "spacer" (hereinafter also referred to as "Sp") is known to those skilled in the art in the art and is described in the literature, see for example Pure Appl. Chem. 2001, 73(5), 888 and C. Tschierske, G. Pelzl, S. Diele, Angew. Chem. 2004, 116, 6340-6368. As used herein, the term "spacer" or "spacer group" refers to a flexible group, for example an alkylene group, which is connected to the mesogenic group or polymerizable group(s) in the polymerizable mesogenic compound.

[0112] In context,

[0113]

[0114] represents a trans-1,4-cyclohexylene ring, and

[0115]

[0116] represents a 1,4-phenylene ring.

[0117] In the group In , a single bond shown between two ring atoms can be attached to any free position of the benzene ring.

[0118] "Organic group" in this context means a carbon or hydrocarbon group.

[0119] "Carbon group" means a monovalent or polyvalent organic group containing at least one carbon atom, wherein the group does not contain other atoms (e.g., -C≡C-) or optionally contains one or more other atoms, such as N, O, S, B, P, Si, Se, As, Te or Ge (e.g., carbonyl, etc.). The term "hydrocarbyl group" means a carbon group that additionally contains one or more H atoms and optionally one or more heteroatoms, such as N, O, S, B, P, Si, Se, As, Te or Ge.

[0120] "Halogen" means F, Cl, Br or I, preferably F or Cl.

[0121] -CO-, -C(=O)- and -C(O)- represent carbonyl groups, i.e.

[0122] The carbon or hydrocarbyl group can be a saturated or unsaturated group. Unsaturated groups are, for example, aryl, alkenyl or alkynyl groups. Carbon or hydrocarbyl groups having more than 3 C atoms can be straight chain, branched and / or cyclic and can also contain spiro connections or fused rings.

[0123] The terms "alkyl," "aryl," "heteroaryl," and the like also include polyvalent groups such as alkylene, arylene, heteroarylene, and the like.

[0124] The term "aryl" refers to an aromatic carbon group or a group derived therefrom. The term "heteroaryl" refers to an "aryl" as defined above containing one or more heteroatoms (preferably selected from N, O, S, Se, Te, Si and Ge).

[0125] Preferred carbon and hydrocarbon radicals are optionally substituted, linear, branched or cyclic alkyl, alkenyl, alkynyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy and alkoxycarbonyloxy radicals having 1 to 40, preferably 1 to 20, very preferably 1 to 12 C atoms, optionally substituted aryl or aryloxy radicals having 5 to 30, preferably 6 to 25 C atoms, or optionally substituted alkylaryl, aralkyl, alkylaryloxy, arylalkyloxy, arylcarbonyl, aryloxycarbonyl, arylcarbonyloxy and aryloxycarbonyloxy radicals having 5 to 30, preferably 6 to 25 C atoms, where one or more C atoms may also be replaced by heteroatoms, preferably selected from N, O, S, Se, Te, Si and Ge.

[0126] Further preferred carbon and hydrocarbyl groups are C1-C 20 Alkyl, C2-C 20 Alkenyl, C2-C 20 Alkynyl, C3-C 20 Allyl, C4-C 20 Alkyldiene, C4-C 20 Polyene, C6-C 20Cycloalkyl, C4-C 15 Cycloalkenyl, C6-C 30 Aryl, C6-C 30 Alkyl aryl, C6-C 30 Aralkyl, C6-C 30 Alkyl aryloxy, C6-C 30 Arylalkoxy, C2-C 30 Heteroaryl, C2-C 30 Heteroaryloxy.

[0127] Particularly preferred is C1-C 12 Alkyl, C2-C 12 Alkenyl, C2-C 12 Alkynyl, C6-C 25 Aryl and C2-C 25 Heteroaryl.

[0128] Further preferred carbon and hydrocarbon radicals are straight-chain, branched or cyclic alkyl radicals having 1 to 20, preferably 1 to 12, C atoms, which are unsubstituted or mono- or polysubstituted by F, Cl, Br, I or CN, and in which one or more non-adjacent CH2 groups can each be replaced independently of one another by -C(R x )=C(R x )-、-C≡C-、-N(R x )-, -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O-, in such a way that the O and / or S atoms are not directly connected to each other.

[0129] R x Preferably it represents H, F, Cl, CN, a linear, branched or cyclic alkyl chain having 1 to 25 C atoms, in which, in addition, one or more non-adjacent C atoms may be replaced by -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O-, and in which one or more H atoms may be replaced by F or Cl, or an optionally substituted aryl or aryloxy group having 6 to 30 C atoms, or an optionally substituted heteroaryl or heteroaryloxy group having 2 to 30 C atoms.

[0130] Preferred alkyl groups are, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, 2-methylbutyl, n-pentyl, sec-pentyl, cyclopentyl, n-hexyl, cyclohexyl, 2-ethylhexyl, n-heptyl, cycloheptyl, n-octyl, cyclooctyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, dodecyl, trifluoromethyl, perfluoro-n-butyl, 2,2,2-trifluoroethyl, perfluorooctyl, perfluorohexyl, and the like.

[0131] Preferred alkenyl groups are, for example, ethenyl, propenyl, butenyl, pentenyl, cyclopentenyl, hexenyl, cyclohexenyl, heptenyl, cycloheptenyl, octenyl, cyclooctenyl and the like.

[0132] Preferred alkynyl groups are, for example, ethynyl, propynyl, butynyl, pentynyl, hexynyl, octynyl and the like.

[0133] 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-decyloxy, n-undecyloxy, n-dodecyloxy, and the like.

[0134] Preferred amino groups are, for example, dimethylamino, methylamino, methylphenylamino, phenylamino and the like.

[0135] Aryl and heteroaryl groups may be monocyclic or polycyclic, i.e. they may contain one ring (e.g. phenyl) or two or more rings, which may also be fused (e.g. naphthyl) or covalently bonded (e.g. biphenyl), or a combination of fused and linked rings. Heteroaryl groups contain one or more heteroatoms, preferably selected from O, N, S and Se.

[0136] Particularly preferred are mono-, bi- or tricyclic aryl radicals having 6 to 25 C atoms and mono-, bi- or tricyclic heteroaryl radicals having 5 to 25 ring atoms, which optionally contain fused rings and are optionally substituted. Further preferred are 5-, 6- or 7-membered aryl and heteroaryl radicals, in which one or more CH groups may additionally be replaced by N, S or O in such a way that the O atoms and / or S atoms are not directly connected to one another.

[0137] Preferred aryl groups are, for example, phenyl, biphenyl, terphenyl, [1,1':3',1"]-terphenyl-2'-yl, naphthyl, anthracenyl, binaphthyl, phenanthrenyl, 9,10-dihydro-phenanthrenyl, pyrene, dihydropyrene, Perylene, tetracene, pentacene, benzopyrene, fluorene, indene, indenofluorene, spirobifluorene, and the like.

[0138] Preferred heteroaryl groups are, for example, 5-membered rings such as pyrrole, pyrazole, imidazole, 1,2,3-triazole, 1,2,4-triazole, tetrazole, furan, thiophene, selenophene, oxazole, isoxazole, 1,2-thiazole, 1,3-thiazole, 1,2,3-oxadiazole, 1,2,4-oxadiazole, 1,2,5-oxadiazole, 1,3,4-oxadiazole, 1,2,3-thiadiazole, 1,2,4-thiadiazole, 1,2,5-thiadiazole, 1,3,4-thiadiazole, 6-membered rings such as pyridine, pyridazine, pyrimidine, pyrazine, 1,3,5-triazine, 1,2,4-triazine, 1,2,3-triazine, 1,2,4,5-tetrazine, 1,2,3,4-tetrazine, 1,2,3,5-tetrazine or fused groups such as indole, isoindole, indole azine, indazole, benzimidazole, benzotriazole, purine, naphthimidazole, phenanthimidazole, pyridimidazole, pyrazinimidazole, quinoxalinoimidazole, benzoxazole, naphthimidazole, anthraxazole, phenanthimidazole, isoxazole, benzothiazole, benzofuran, isobenzofuran, dibenzofuran, quinoline, isoquinoline, pteridine, benzo-5,6-quinoline, benzo-6,7-quinoline, benzo- 7,8-quinoline, benzisoquinoline, acridine, phenothiazine, phenoxazine, benzopyridazine, benzopyrimidine, quinoxaline, phenazine, naphthyridine, azacarbazole, benzocarboline, phenanthridine, phenanthroline, thieno[2,3b]thiophene, thieno[3,2b]thiophene, dithienothiophene, isobenzothiophene, dibenzothiophene, benzothiophene, benzothiadiazolethiophene, or a combination of these groups.

[0139] The aryl and heteroaryl groups mentioned above and below may also be substituted by alkyl, alkoxy, thioalkyl, fluorine, fluoroalkyl or other aryl or heteroaryl groups.

[0140] (Non-aromatic) alicyclic and heterocyclic groups include both saturated rings, i.e. rings containing only single bonds, and partially unsaturated rings, i.e. those which may also contain multiple bonds. The heterocyclic ring contains one or more heteroatoms, preferably selected from Si, O, N, S and Se.

[0141] (Non-aromatic) alicyclic groups and heterocyclic groups can be monocyclic, i.e. only contain one ring (e.g. cyclohexane), or polycyclic, i.e. contain multiple rings (e.g. decalin or bicyclooctane). Particularly preferred are saturated groups. In addition, preferably there is a single-, double- or tricyclic group of 5-25 annular atoms, which optionally contains a fused ring and is optionally substituted. Further preferred are 5-, 6-, 7- or 8-membered carbocyclic groups, wherein in addition, one or more C atoms may be substituted by Si and / or one or more CH groups may be substituted by N and / or one or more non-adjacent CH2 groups may be substituted by-O- and / or-S-.

[0142] Preferred alicyclic 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 condensed groups such as tetralin, decalin, indane, bicyclo[1.1.1]pentane-1,3-diyl, bicyclo[2.2.2]octane-1,4-diyl, spiro[3.3]heptane-2,6-diyl, octahydro-4,7-methanoindan-2,5-diyl.

[0143] Preferred substituents for the above-mentioned cyclic groups are, for example, solubility-promoting groups, such as alkyl or alkoxy groups; electron-withdrawing groups, such as fluorine, nitro or nitrile; or substituents for increasing the glass transition temperature (Tg) of the polymer, in particular bulky groups, such as tert-butyl or optionally substituted aryl groups.

[0144] Preferred substituents of the above-mentioned cyclic groups, hereinafter also referred to as "L S ", such as F, Cl, Br, I, -CN, -NO2, -NCS, -C(=O)N(R x )2、-C(=O)Y 1 、-C(=O)R x 、-N(R x )2, a linear or branched alkyl group, an alkoxy group, an alkylcarbonyl group, an alkoxycarbonyl group, an alkylcarbonyloxy group or an alkoxycarbonyloxy group having 1 to 25 carbon atoms, in which one or more hydrogen atoms may be optionally replaced by F or Cl, an optionally substituted silyl group having 1 to 20 silicon atoms, or an optionally substituted aryl group having 6 to 25, preferably 6 to 15 carbon atoms.

[0145] where R x represents H, F, Cl, CN, or a straight-chain, branched or cyclic alkyl group having 1 to 25 C atoms, wherein one or more non-adjacent CH2- groups are optionally replaced by -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O- in such a way that the O- and / or S- atoms are not directly connected to one another, and wherein one or more H atoms are each optionally replaced by F, Cl, P- or P-Sp-, and

[0146] Y 1 Represents halogen.

[0147] "Substituted silyl or aryl" preferably means substituted with halogen, -CN, R 0 、-OR 0 、-CO-R 0 、-CO-OR 0、-O-CO-R 0 OR-O-CO-OR 0 Substituted, where R 0 represents H or an alkyl group having 1 to 20 C atoms.

[0148] Particularly preferred substituents L S For example, F, Cl, CN, NO2, CH3, C2H5, OCH3, OC2H5, COCH3, COC2H5, COOCH3, COOC2H5, CF3, OCF3, OCHF2, OC2F5, and phenyl.

[0149] Preferably or

[0150] wherein L has one of the meanings indicated above.

[0151] The polymerizable group P is a group suitable for polymerization reactions (e.g., free radical or ionic chain polymerization, addition polymerization, or condensation polymerization), or a group suitable for polymer-analogous reactions (e.g., addition or condensation on the polymer backbone). Particularly preferred are groups suitable for chain polymerization, in particular those containing a C═C double bond or a —C≡C— triple bond, and groups suitable for ring-opening polymerization, such as oxetane or epoxy groups.

[0152] 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-, 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-, where W 1 represents H, F, Cl, CN, CF3, phenyl or alkyl having 1 to 5 C atoms, in particular H, F, Cl or CH3, W 2 and W 3 each independently of one another represents H or alkyl having 1 to 5 C atoms, in particular H, methyl, ethyl or n-propyl, W 4 、W 5 and W 6 each independently represents Cl, oxaalkyl or oxacarbonylalkyl having 1 to 5 C atoms, W 7 and W 8 Each independently of one another represents H, Cl or an alkyl group having 1 to 5 C atoms, Phe represents 1,4-phenylene, which is optionally substituted by one or more groups L different from P-Sp- as defined above, k1, k2 and k3 each independently of one another represent 0 or 1, k3 preferably represents 1, and k4 represents an integer from 1 to 10.

[0153] 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-, where W 1 represents H, F, Cl, CN, CF3, phenyl or alkyl having 1 to 5 C atoms, in particular H, F, Cl or CH3, W 2 and W 3each independently of one another represents H or alkyl having 1 to 5 C atoms, in particular H, methyl, ethyl or n-propyl, W 4 、W 5 and W 6 each independently represents Cl, an oxaalkyl group or an oxacarbonylalkyl group having 1 to 5 C atoms, W 7 and W 8 Each independently represents H, Cl or an alkyl group having 1 to 5 C atoms, Phe represents 1,4-phenylene, k1, k2 and k3 each independently represent 0 or 1, k3 preferably represents 1, and k4 represents an integer of 1 to 10.

[0154] Very preferably the group P is 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-, and

[0155] Other particularly preferred polymerizable groups P are selected from vinyloxy, acrylate, methacrylate, fluoroacrylate, chloroacrylate, oxetane and epoxy groups, most preferably methacrylate.

[0156] If the spacer group Sp is different from a single bond, it is preferably of the formula Sp"-X", so that the respective group P-Sp- corresponds to the formula P-Sp"-X"-, where

[0157] Sp" denotes a straight-chain or branched alkylene radical having 1 to 20, preferably 1 to 12, C atoms, which is optionally mono- or polysubstituted by F, Cl, Br, I or CN, and in which, in addition, one or more non-adjacent CH2 groups are each independently substituted 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- are replaced in such a way that O and / or S atoms are not directly connected to each other,

[0158] X" means -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O-, -CO-N(R 0 )-、-N(R 0 )-CO-、-N(R 0 )-CO-N(R 00 )-, -OCH2-, -CH2O-, -SCH2-, -CH2S-, -CF2O-, -OCF2-, -CF2S-, -SCF2-, -CF2CH2-, -CH2CF2-, -CF2CF2-, -CH=N-, -N=CH-, -N=N-, -CH=CR 0 -、-CY 2 =CY 3 -, -C≡C-, -CH=CH-CO-O-, -O-CO-CH=CH- or a single bond,

[0159] R 0 and R 00 each independently of one another represents H or an alkyl group having 1 to 20 C atoms, and

[0160] Y 2 and Y 3 Each independently represents H, F, Cl or CN.

[0161] X" is preferably -O-, -S-, -CO-, -COO-, -OCO-, -O-COO-, -CO-NR 0 -、-NR 0 -CO-、-NR 0 -CO-NR 00 - or single key.

[0162] Typical spacer groups Sp and -Sp"-X"- are, for example, -(CH2) p1 -、-(CH2) p1 -O-, -(CH2) p1 -O-CO-, -(CH2) p1 -CO-O-, -(CH2) p1 -O-CO-O-, -(CH2CH2O) q1 -CH2CH2-、-CH2CH2-S-CH2CH2-、-CH2CH2-NH-CH2CH2- or -(SiR 0 R 00 -O) p1 -, wherein p1 is an integer from 1 to 12, q1 is an integer from 1 to 3, and R 0 and R 00 has the meaning indicated above.

[0163] Particularly preferred groups Sp and -Sp"-X"- are -(CH2) p1 -、-(CH2) p1 -O-, -(CH2) p1 -O-CO-, -(CH2) p1 -CO-O-, -(CH2) p1 -O-CO-O-, wherein p1 and q1 have the meanings indicated above.

[0164] Particularly preferred radicals Sp" are in each case linear ethylene, propylene, butylene, pentylene, hexylene, heptylene, octylene, nonylene, decylene, undecylene, dodecylene, octadecylene, ethyleneoxyethylene, methyleneoxybutylene, ethylenethioethylene, ethylene-N-methylimino-ethylene, 1-methylalkylene, vinylene, propenylene and butenylene.

[0165] In one embodiment of the invention, the compounds of formula I or II and subformulae thereof contain a spacer group Sp substituted with one or more polymerizable groups P such that the group Sp-P corresponds to Sp(P) s , s is ≥2 (branched polymerizable group).

[0166] Preferred compounds of formula I according to this embodiment are those wherein s is 2, ie compounds containing the group Sp(P) 2. Very preferred compounds of formula I according to this preferred embodiment contain a group selected from the group consisting of:

[0167] -X-alkyl-CHPP S1

[0168] -X-alkyl-CH((CH2) aa P)((CH2) bb P) S2

[0169] -XN((CH2) aa P)((CH2) bb P) S3

[0170] -X-alkyl-CHP-CH2-CH2P S4

[0171] -X-alkyl-C(CH2P)(CH2P)-C aa H 2aa+1 S5

[0172] -X-alkyl-CHP-CH2P S6

[0173] -X-alkyl-CPP-C aa H 2aa+1 S7

[0174] -X-alkyl-CHPCHP-C aa H 2aa+1 S8

[0175] wherein P is as defined in formula I,

[0176] Alkyl represents a single bond or a straight-chain or branched alkylene radical having 1 to 12 C atoms, which is unsubstituted or mono- or polysubstituted by F, Cl or CN, and in which one or more non-adjacent CH2 groups may each independently of one another be substituted by -C(R 0 )=C(R 0 )-、-C≡C-、-N(R 0 )-, -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O- substitution, where R 0 has the meaning indicated above,

[0177] aa and bb each independently represent 0, 1, 2, 3, 4, 5 or 6,

[0178] X has one of the meanings indicated for X", and is preferably O, CO, SO2, O-CO-, CO-O or a single bond.

[0179] Preferred spacer groups Sp(P)2 are selected from formulae S1, S2 and S3.

[0180] Very preferred spacer groups Sp(P)2 are selected from the following sub-formulas:

[0181] -CHPP S1a

[0182] -O-CHPP S1b

[0183] -CH2-CHPP S1c

[0184] -OCH2-CHPP S1d

[0185] -CH(CH2-P)(CH2-P) S2a

[0186] -OCH(CH2-P)(CH2-P) S2b

[0187] -CH2-CH(CH2-P)(CH2-P) S2c

[0188] -OCH2-CH(CH2-P)(CH2-P) S2d

[0189] -CO-NH((CH2)2P)((CH2)2P) S3a

[0190] In the compounds of formula I, II or III and subformulae thereof as described above and below, P is preferably selected from the group consisting of vinyloxy, acrylate, methacrylate, fluoroacrylate, chloroacrylate, oxetane and epoxy, most preferably from acrylate and methacrylate.

[0191] More preferred are compounds of the formula I, II or III and subformulae thereof as described above and below, wherein all polymerizable groups P present in the compound have the same meaning and very preferably represent acrylate or methacrylate groups, most preferably methacrylate groups.

[0192] In the compounds of formulae I, II or III and subformulae thereof as described above and below, R preferably represents P-Sp-.

[0193] More preferred are compounds of formula I, II or III and subformulae thereof as described above and below, wherein Sp represents a single bond or -(CH2) p1 -、-O-(CH2) p1 -、-O-CO-(CH2) p1 or -CO-O-(CH2) p1 , wherein p1 is 2, 3, 4, 5 or 6, and if Sp is -O-(CH2) p1 -、-O-CO-(CH2) p1 or -CO-O-(CH2) p1 , then the O-atom or CO-group, respectively, is attached to the benzene ring.

[0194] More preferred are compounds of formula I, II or III and subformulae thereof as described above and below, wherein one or no group Sp is different from a single bond and wherein Sp is not a single bond, Sp is preferably selected from -(CH2) p1 -、-O-(CH2) p1 -、-O-CO-(CH2) p1 or -CO-O-(CH2) p1 , wherein p1 is 2, 3, 4, 5 or 6, and if Sp is -O-(CH2) p1 -、-O-CO-(CH2) p1 or -CO-O-(CH2) p1 , then the O-atom or CO-group, respectively, is attached to the benzene ring.

[0195] Preferred compounds of formula I are selected from the following:

[0196]

[0197]

[0198] in

[0199] P is a polymerizable group, preferably a methacrylate group,

[0200] Sp is a spacer group, and

[0201] L 1 , L 3 are independently as defined in Formula I above.

[0202] Very preferred formula I is selected from the following subformulae:

[0203]

[0204]

[0205] Preferred compounds of formula II are selected from the following:

[0206]

[0207]

[0208] Among them, P, L 1 and L 2 As defined in Formula II, and

[0209] Sp is a spacer group.

[0210] Very preferred compounds of formula II are selected from the following sub-formulae:

[0211]

[0212]

[0213] Preferred compounds of formula I or II and subformulae thereof are selected from the following preferred embodiments, including any combination thereof:

[0214] - all groups P in the compound have the same meaning,

[0215] -P is selected from acrylate, methacrylate and oxetane, very preferably acrylate or methacrylate,

[0216] -P is a methacrylate group,

[0217] - r = 0 and s = 0,

[0218] -R L It is a methyl group or an ethyl group, preferably a methyl group.

[0219] - all Sp groups in formula I are single bonds,

[0220] -When different from a single bond, Sp is -(CH2) p2-, -(CH2) p2 -O-, -(CH2) p2 -CO-O-, -(CH2) p2 -O-CO-, wherein p2 is 2, 3, 4, 5 or 6, and the O-atom or CO-group is attached to the benzene ring,

[0221] -Sp is a single bond or represents a compound selected from -(CH2) p2 -, -(CH2) p2 -O-, -(CH2) p2 -CO-O- and -(CH2) p2 -O-CO- spacer, wherein p2 is 2, 3, 4, 5 or 6, and the O-atom or CO- group is attached to the benzene ring, respectively, and

[0222] -L 1 Indicates F, Cl or CH3.

[0223] In a preferred embodiment of the present invention, the LC medium comprises one or more, preferably one or two, self-aligning additives of formula III for homeotropic alignment.

[0224] The self-aligning additives can be polymerized in the LC medium under similar conditions to those applied to the RMs in the PSA process. Typically, they will be polymerized simultaneously with the RMs in the PSA process.

[0225] Suitable SA additives for inducing homeotropic alignment, in particular for 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.

[0226] In formula III, the MES group is preferably a group selected from the following structures, which may be replaced by any substituent L 1 and -Sp-P monosubstituted or polysubstituted:

[0227]

[0228]

[0229] in

[0230] L 1 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 may each be replaced by F or Cl,

[0231] P represents a polymerizable group, and

[0232] Sp represents a spacer group or a single bond,

[0233] And the dotted line represents the polar anchoring group R a attachment point.

[0234] Preferably, the self-aligning additive for vertical alignment is selected from the group consisting of:

[0235] R 1 -[A 2 -Z 2 ] m -A 1 -R a IIIa

[0236] in

[0237] A 1 , A 2 each independently of one another represents an aromatic, heteroaromatic, alicyclic or heterocyclic radical, which may also contain fused rings and which may also be mono- or polysubstituted by radicals L or -Sp-P,

[0238] L in each case independently of one another represents H, 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 may each be replaced by F or Cl,

[0239] P represents a polymerizable group,

[0240] Sp represents a spacer group or a single bond,

[0241] Z 2represents, 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 -, -CF2CH2-, -CH2CF2-, -(CF2) n1 -, -CH=CH-, -CF=CF-, -C≡C-, -CH=CH-COO-, -OCO-CH=CH-, -(CR 0 R 00 ) n1 -, -CH(-Sp-P)-, -CH2CH-(-Sp-P)- or -CH(-Sp-P)CH(-Sp-P)-,

[0242] n1 means 1, 2, 3 or 4,

[0243] m represents 1, 2, 3, 4, 5 or 6,

[0244] R 0 represents in each case, independently of one another, an alkyl radical having 1 to 12 C atoms,

[0245] R 00 represents in each case, independently of one another, H or an alkyl radical having 1 to 12 C atoms,

[0246] R 1 independently of one another represent H, halogen, straight-chain, branched or cyclic alkyl having 1 to 25 C atoms, wherein, in addition, one or more non-adjacent CH2 groups may each be replaced by -C≡C-, -CH=CH-, -O-, -S-, -CO-, -CO-O-, -O-CO- or -O-CO-O- in such a way that the O and / or S atoms are not directly connected to one another, and wherein, in addition, one or more H atoms may each be replaced by F or Cl, or a -Sp-P group, and

[0247] R a As defined above, preferably refers to a polar anchoring group, which is further defined as having at least one selected from -OH, -NH2, -NHR 11 , C(O)OH and -CHO groups, where R 11 represents an alkyl group having 1 to 12 C atoms.

[0248] In a preferred embodiment of the present invention, the self-aligning additive is a polymerizable compound having at least one polymerizable group P, more preferably wherein the ring element A 1 and A 2At least one of them is substituted with at least one -Sp-P group.

[0249] In a further preferred embodiment, the LC medium or polymer-stabilized SA-VA display according to the invention comprises one or more self-aligning additives selected from Table D below.

[0250] Anchoring group R of self-aligning additive a More preferably, the anchoring group is defined as

[0251]

[0252] or

[0253]

[0254] in

[0255] p means 1 or 2,

[0256] q means 2, 3 or 4,

[0257] B represents a substituted or unsubstituted ring system or a condensed ring system, preferably a ring system selected from benzene, pyridine, cyclohexane, dioxane or tetrahydropyran,

[0258] Y independently represents -O-, -S-, -C(O)-, -C(O)O-, -OC(O)-, -NR 11 - or single key,

[0259] o represents 0 or 1,

[0260] X 1 independently represent H, alkyl, fluoroalkyl, OH, NH2, NHR 11 ,NR 11 2, -PO(OR 11 )2,-SO2R 11 , OR 11 , C(O)OH, or -CHO,

[0261] At least one group X 1 represents a group selected from -OH, -NH2, -NHR 11 ,-PO(OR 11 )2,-SO2R 11 , C(O)OH, and -CHO groups,

[0262] Z 1Independently -(CO)-CH2(CO)OCH3, -(CO)-CH2(CO)-(C=CH2)-OCH3, -(CO)-CH2(CO)-(CH=CH)-OCH3, -(CO)-(CO)OCH3, -CH2-(CO)-(CO)OCH3, -(CO)-CH3, -(CO)-CH2(CO)-(CH2CH2)-OCH3,

[0263] P is a polymerizable group,

[0264] R 11 represents an alkyl group having 1 to 12 C atoms,

[0265] R 12 represents H, an alkyl group having 1 to 12 C atoms, P or X 1 ,

[0266] Sp a , Sp c , Sp d each independently of one another represents a spacer group or a single bond, and

[0267] Sp b represents a tri- or tetravalent group, preferably CH, N or C.

[0268] Formulae III and IIIa optionally include polymerizable compounds. In the present application, "a medium comprising a compound of formula III / IIIa" refers to both a medium comprising a compound of formula III / IIIa and a medium which alternatively comprises a polymerized form of said compound.

[0269] In case one or more compounds of formula III are substituted by one or more polymerisable groups (-Sp-P), the LC media according to the invention comprise

[0270] 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 is a compound of formula II and at least one of which is a compound of formula III,

[0271] - a liquid-crystalline component B), hereinafter also referred to as "LC host mixture", which comprises, preferably consists of, one or more mesogenic or liquid-crystalline compounds.

[0272] In the compounds of formula IIIa and its subformulas, Z 1 and Z 2 Preferably represents a single bond, -C2H4-, -CF2O- or -CH2O-. In a particularly preferred embodiment, Z 1 and Z 2 Each independently represents a single bond.

[0273] In the compounds of the formula IIIa, the radical L independently in each case preferably represents F or alkyl, preferably CH3, C2H5 or C3H7.

[0274] Preferred compounds of formula III are illustrated by the following sub-formulae III-A to III-D

[0275]

[0276] where R 1 , R a , A 2 , Z 2 , Sp and P have the meanings defined above for formula IIIa,

[0277] L 1 are independently defined as L in formula IIIa above,

[0278] m is independently 1, 2 or 3, and

[0279] r1 is independently 0, 1, 2, 3, or 4, preferably 0, 1 or 2.

[0280] In the compounds of formula III-A to III-D, L 1 Preferably it represents F or alkyl, preferably CH3, C2H5 or C3H7.

[0281] In a preferred embodiment, r2 represents 1 and / or r1 represents 0.

[0282] The polymerizable group P of formula III, IIIa, III-A to III-D is preferably a methacrylate group, an acrylate group or other substituted acrylate groups, most preferably a methacrylate group.

[0283] In the above and below, in formula IIIa or III-A to III-D and subformulae thereof, Z 1 Preferably independently represents a single bond or -CH2CH2-, and very particularly represents a single bond.

[0284] R a Preferred representation

[0285] or

[0286] Where p = 1, 2, 3, 4, 5 or 6,

[0287] x is 1 or 0, preferably 1, and

[0288] R 22 is H, methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, n-pentyl or -CH2CH2-tert-butyl,

[0289] In particular,

[0290] -O(CH2)2-OH, -O(CH2)3-OH,

[0291]

[0292]

[0293] or

[0294]

[0295] In formula IIIa and subformulas of formula IIIa, R 1 Preferably represents a straight-chain alkyl group or a branched-chain alkyl group having 1 to 8 C atoms, preferably a straight-chain alkyl group. In the compounds of formula IIIa or III-A to III-D, R 1 More preferably, it represents CH3, C2H5, n-C3H7, n-C4H9, n-C5H 11 , n-C6H 13 Or CH2CH(C2H5)C4H9. 1 Furthermore, it may represent alkenyloxy, in particular OCH2CH=CH2, OCH2CH=CHCH3, OCH2CH=CHC2H5 or alkoxy, in particular OC2H5, OC3H7, OC4H9, OC5H 11 and OC6H 13 . Particularly preferred is R 1 represents a straight chain alkyl group, preferably C5H 11 .

[0296] The compounds and intermediates of the formulae I, II and III and their subformulae can be prepared analogously to the methods known to those skilled in the art and described in standard texts of organic chemistry (e.g. Houben-Weyl, Methoden der organischen Chemie [Methods of Organic Chemistry], Thieme-Verlag, Stuttgart).

[0297] For example, the compounds of formula I and II can be synthesized by esterifying or etherifying intermediates using corresponding acids, acid derivatives or halogenated compounds containing polymerizable groups P, wherein the groups Sp-P at both ends represent OH.

[0298] For example, acrylic acid esters or methacrylic acid esters 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 using dicyclohexylcarbodiimide (DCC), N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide (EDC) or N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride and DMAP.

[0299] Further suitable methods are shown in the Examples.

[0300] To produce PSA displays, the polymerisable compounds contained in the LC medium are polymerised or crosslinked (if one compound contains two or more polymerisable groups) by polymerisation in situ in the LC medium (between the substrates of the LC display), optionally while applying a voltage to the electrodes.

[0301] The structure of the PSA display according to the invention corresponds to the typical geometry of PSA displays, as described in the prior art cited at the outset. Geometries without protrusions are preferred, particularly those in which the electrodes on the color filter side are unstructured and only the electrodes on the TFT side have slots. A particularly suitable and preferred electrode structure for PS-VA displays is described, for example, in US 2006 / 0066793 A1.

[0302] A preferred PSA-type LC display according to the invention comprises:

[0303] a first substrate comprising a pixel electrode defining a pixel area (the pixel electrode being connected to a switching element arranged in each pixel area and optionally comprising a micro-slit pattern), and optionally a first alignment layer arranged on the pixel electrode,

[0304] a second substrate comprising a common electrode layer (which may be arranged on the entire portion of the second substrate facing the first substrate), and optionally a second alignment layer,

[0305] - an LC layer arranged between a first and a second substrate and comprising an LC medium according to the invention as described above and below, wherein the polymerisable component (A) may also be polymerisable.

[0306] The self-aligning additives contained in the medium induce homeotropic alignment (perpendicular to the surface) or tilted homeotropic alignment of the LC layer.

[0307] The LC layer containing 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 fill (ODF) method or inkjet printing. The polymerizable components of the LC medium are then polymerized, for example, by UV photopolymerization. The polymerization can be carried out in one step or in two or more steps.

[0308] A PSA display may include other elements such as color filters, a black matrix, a passivation layer, an optical retardation layer, transistor elements for addressing the individual pixels, etc., all of which are well known to those skilled in the art.

[0309] Those skilled in the art can design the electrode structure depending on the type of individual display. For example, for a PS-VA display, multi-domain orientation of LC molecules can be induced by providing electrodes with slits and / or bumps or protrusions to produce two, four or more differently tilted alignment directions.

[0310] After polymerization, the polymerizable compound forms a cross-linked polymer, which results in a certain pre-tilt of the LC molecules in the LC medium. Without wishing to be bound by a particular theory, it is believed that at least a portion of the cross-linked polymer formed by the polymerizable compound phase separates or precipitates from the LC medium and forms a polymer layer on the substrate or electrode. Microscopic measurements (e.g., SEM and AFM) have confirmed that at least a portion of the formed polymer accumulates at the LC / substrate interface.

[0311] The polymerization can be carried out in one step. It is also possible to first carry out the polymerization in a first step (optionally with simultaneous application of a voltage) in order to produce a pretilt angle, and then polymerize or crosslink the compounds that did not react in the first step in a second polymerization step without application of a voltage ("final curing").

[0312] 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 compound to UV radiation.

[0313] Optionally, one or more polymerization initiators are added to the LC medium. Suitable conditions for polymerization and suitable types and amounts of initiators are known to those skilled in the art and are described in the literature. Suitable for free-radical polymerization are, for example, commercially available photoinitiators or (Ciba AG). If a polymerization initiator is used, its proportion is preferably from 0.001 to 5% by weight, particularly preferably from 0.001 to 1% by weight.

[0314] The polymerizable compounds according to the invention are also suitable for initiator-free polymerization, which is accompanied by considerable advantages, such as lower material costs and, in particular, less contamination of the LC medium by possible residual amounts of initiator or its degradation products. The polymerization can thus also be carried out without the addition of initiators. In a preferred embodiment, the LC medium therefore contains no polymerization initiator.

[0315] The LC medium may also contain one or more stabilizers in order to prevent undesired spontaneous polymerization of the RMs, for example during storage or transport. Suitable types and amounts of stabilizers are known to those skilled in the art and are described in the literature. Particularly suitable are, for example, the stabilizers commercially available from series (Ciba AG), such as 1076. If stabilizers are used, their proportion is preferably 10-500,000 ppm, particularly preferably 50-50,000 ppm (1000 ppm=0.1% by weight), based on the total amount of RM or polymerizable component (component A).

[0316] The combinations of polymerizable components disclosed herein are advantageously sensitive to UV radiation, even in the absence of a photoinitiator.The medium can be used at wavelengths of 300-380 nm, or even 340 nm or greater and preferably 400 nm or less.

[0317] The polymerizable compounds of the formulae I, II and III do in particular exhibit good UV absorption and are therefore particularly suitable for use in a process for the production of PSA displays comprising one or more of the following features:

[0318] - the polymerizable medium in the display is exposed to UV light in a 2-step process comprising a first UV exposure step ("UV-1 step") to create the tilt angle, and a second UV exposure step ("UV-2 step") to complete the polymerization,

[0319] - Exposure of the polymerizable medium in the display to UV light generated by energy-saving fluorescent UV lamps (also known as "green UV lamps"). These lamps are characterized by relatively low intensities in their absorption spectrum between 300 and 380 nm (1 / 100-1 / 10 of conventional UV1 lamps) and are preferably used in the UV2 step, but can also be used optionally in the UV1 step when avoiding high intensities is essential for the process.

[0320] - In the display the polymerizable medium is exposed to UV light generated by a UV lamp having a radiation spectrum shifted to longer wavelengths (preferably 340 nm or longer) in order to avoid the short UV light exposure in the PS-VA process.

[0321] Both lower intensity and UV shifted to longer wavelengths are used to protect the organic layers from damage that can be caused by UV light.

[0322] A preferred embodiment of the present invention relates to a process for producing a PSA display as described above and below, comprising one or more of the following features:

[0323] - the polymerisable LC medium is exposed to UV light in a 2-step process comprising a first UV exposure step ("UV-1 step") to produce the tilt angle and a second UV exposure step ("UV-2 step") to complete the polymerisation,

[0324] The polymerizable LC medium was exposed to UV light with a power of 0.5 mW / cm 2 Up to 10mW / cm 2 UV light in the wavelength range of 300-380 nm of an intensity of 100 nm, preferably for the UV2 step, and optionally also for the UV1 step,

[0325] - the polymerisable LC medium is exposed to UV light having a wavelength of 340 nm or longer, and preferably 400 nm or shorter.

[0326] This preferred method is performed, for example, using a desired UV lamp, or using a bandpass filter and / or a cutoff filter that is substantially transmissive for UV light having the desired wavelength and substantially blocks UV light having the undesired wavelength. For example, when UV light having a wavelength λ of 300-400 nm is desired, UV exposure can be performed using a broad bandpass filter that is substantially transmissive for wavelengths in the range of 300 nm < λ < 400 nm. When UV light having a wavelength λ greater than 340 nm is desired, UV exposure can be performed using a cutoff filter that is substantially transmissive for wavelengths in the range of λ > 340 nm.

[0327] "Substantially transmit" means that the filter transmits a majority, preferably at least 50%, of the intensity of incident light of a desired wavelength. "Substantially block" means that the filter does not transmit a majority, preferably at least 50%, of the intensity of incident light of an undesired wavelength. "Desired (undesired) wavelength" means, for example, wavelengths within (outside) a given λ range in the case of a bandpass filter, and wavelengths above (below) a given λ value in the case of a cutoff filter.

[0328] This preferred method makes it possible to manufacture displays by using longer UV wavelengths, thereby reducing or even avoiding the harmful and damaging effects of the short UV light component.

[0329] UV radiation energy is usually 6 to 100 J / cm 2 , which depends on the production method conditions.

[0330] The LC media according to the present invention preferably do essentially consist of a polymerisable component A), or one or more polymerisable compounds of the formulae I, II and III as described above and below, and an LC component B), or an LC host mixture.

[0331] However, the LC medium may additionally comprise one or more other components or additives, preferably selected from the list including, but not limited to, comonomers, chiral dopants, polymerization initiators, inhibitors, stabilizers, surfactants, wetting agents, lubricants, dispersants, hydrophobic agents, binders, spreading agents, flow improvers, defoamers, degassing agents, diluents, reactive diluents, auxiliaries, colorants, dyes, pigments and nanoparticles.

[0332] Preference is furthermore given to LC media in which the liquid-crystalline component B) or the LC host mixture has a nematic LC phase and preferably no chiral liquid-crystalline phase.

[0333] The LC component B) or the LC host mixture is preferably a nematic LC mixture.

[0334] Preference is furthermore given to achiral compounds of the formula I, and LC media in which the compounds of components A and / or B are selected exclusively from the group consisting of achiral compounds.

[0335] Preferably, the proportion of polymerizable component A) in the LC medium is from >0.3 to <5%, very preferably from >0.6 to <4%, most preferably from 0.9 to 3%.

[0336] Preferably, the proportion of compounds of the formula I in the LC medium is >0 to <5%, very preferably >0.3 to <3%, most preferably 0.1 to 2.5%.

[0337] Preferably, the proportion of the compound of the formula II in the LC medium is >0.1 to <5%, very preferably >0.2 to <3%, most preferably 0.2 to 1.5%.

[0338] Preferably, the proportion of component B) in the LC medium is from 95 to <100%, very preferably from 97 to <100%.

[0339] In another preferred embodiment, the polymerizable component B) comprises, in addition to the compounds of the formulae I, II and III, one or more further polymerizable compounds ("comonomers"), preferably selected from RMs.

[0340] Suitable and preferred mesogenic comonomers are selected from the following formula:

[0341]

[0342]

[0343]

[0344]

[0345] Wherein, each group has the following meaning:

[0346] P 1 、P 2 and P 3 each independently of one another represents an acrylate group or a methacrylate group,

[0347] Sp 1 、Sp 2 and Sp 3 each independently of one another represents a single bond or a spacer group (having one of the meanings as given above and below for Sp), and particularly preferably represents -(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 the group P 1 -Sp 1 -、P 1 -Sp 2 - and P 3 -Sp 3 - One or more of them can represent R aa , provided that there is a group P 1 -Sp 1 -、P 2 -Sp 2 - and P 3 -Sp 3 - at least one of them is different from R aa ,

[0348] R aa represents H, F, Cl, CN or a straight-chain or branched alkyl radical having 1 to 25 C atoms, wherein one or more further non-adjacent CH2 groups may also be replaced independently of one another 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 the O and / or S atoms are not directly connected to each other, and wherein one or more additional H atoms may be replaced by F, Cl, CN or P 1 -Sp 1- alternatively, particularly preferably a straight-chain or branched, optionally mono- or polyfluorinated alkyl, alkoxy, alkenyl, alkynyl, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy radical having 1 to 12 C atoms, where alkenyl and alkynyl have at least two C atoms and branched radicals have at least three C atoms,

[0349] R 0 、R 00 each independently of one another and identically or differently on each occurrence represents H or alkyl having 1 to 12 C atoms,

[0350] R y and R z Each independently represents H, F, CH3 or CF3,

[0351] X 1 、X 2 and X 3 each independently represents -CO-O-, -O-CO- or a single bond,

[0352] Z 1 Indicates -O-, -CO-, -C(R y R z )- or -CF2CF2-,

[0353] Z 2 and Z 3 Each independently represents -CO-O-, -O-CO-, -CH2O-, -OCH2-, -CF2O-, -OCF2- or -(CH2) n -, where n is 2, 3, or 4,

[0354] L, on each occurrence, identically or differently, represents F, Cl, CN or linear or branched, optionally mono- or polyfluorinated alkyl, alkoxy, alkenyl, alkynyl, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy having 1 to 12 C atoms, preferably F,

[0355] L' and L" each independently represent H, F or Cl,

[0356] r represents 0, 1, 2, 3 or 4,

[0357] s represents 0, 1, 2 or 3,

[0358] t represents 0, 1 or 2,

[0359] x represents 0 or 1.

[0360] Especially preferred are compounds of formulae M2, M13, M17, M22, M23, M24 and M30.

[0361] The preferred comonomer is of formula M2-1:

[0362]

[0363] in

[0364] L 4 , L 5 independently represents F, Cl or a straight-chain, branched or cyclic alkyl group having 1 to 5 C atoms, wherein one or more non-adjacent CH2 groups are optionally replaced by -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O- in such a way that the O and / or S atoms are not directly connected to each other, and wherein one or more H atoms are each optionally replaced by F or Cl, preferably F, Cl, CH3 or CH2CH3.

[0365] Especially selected from the formula M2-1-1 to M2-1-4

[0366]

[0367] In a preferred embodiment of the present invention, the LC medium comprises a compound of formula M2, wherein L is as defined above, but is not methoxy, preferably formula M2-1 and most preferably formula M2-1-1.

[0368] More preferred are the trireactive compounds M15 to M30, in particular M17, M18, M19, M22, M23, M24, M25, M26, M30 and M31.

[0369] In the compounds of formulae M1 to M29, the group

[0370] Preferred

[0371] or

[0372] wherein L has, identically or differently on each occurrence, one of the meanings given above and below and is preferably F, Cl, CN, NO2, CH3, C2H5, C(CH3)3, CH(CH3)2, CH2CH(CH3)C2H5, OCH3, OC2H5, COCH3, COC2H5, COOCH3, COOC2H5, CF3, OCF3, OCHF2, OC2F5 or P-Sp-, very preferably F, Cl, CN, CH3, C2H5, OCH3, COCH3, OCF3 or P-Sp-, more preferably F, Cl, CH3, OCH3, COCH3 or OCF3 and in particular F or CH3.

[0373] In addition to the polymerizable compounds described above, the LC medium for the LC display according to the invention comprises an LC mixture ("host mixture") comprising one or more, preferably two or more, LC compounds selected from non-polymerizable, low molecular weight compounds. These LC compounds are selected such that they are stable and / or unreactive towards polymerization reactions under the conditions applied to the polymerization of the polymerizable compounds.

[0374] In principle, any LC mixture suitable for conventional displays is suitable as a host mixture. Suitable LC mixtures are known to those skilled in the art and are described in the literature, for example in EP 1 378 557 A1 for VA displays and in EP 1 306 418 A1 and DE 102 24 046 A1 for OCB displays.

[0375] In addition to the polymerizable component A) as described above, the LC media according to the invention further comprise an LC component B) or an LC host mixture comprising one or more, preferably two or more, LC compounds selected from non-polymerizable low molecular weight compounds. These LC compounds are selected such that they are stable and / or unreactive towards polymerization reactions under the conditions applied to the polymerization of the polymerizable compounds.

[0376] In a preferred embodiment, the LC medium contains an LC component B) based on a compound having negative dielectric anisotropy or an LC host mixture. Such LC media are particularly suitable for PS-VA and PS-UB-FFS displays. Particularly preferred embodiments of such LC media are those of the following sections a) to y):

[0377] a) LC media, wherein component B) or the LC host mixture comprises one or more compounds selected from the group consisting of formulae CY and PY:

[0378]

[0379] in

[0380] a means 1 or 2,

[0381] b represents 0 or 1,

[0382] express or

[0383] R 1 and R 2 each independently of one another represents an alkyl radical having 1 to 12 C atoms, wherein one or two non-adjacent CH2 groups may also be replaced by -O-, -CH=CH-, -C≡C-, -CO-, -OCO- or -COO- is replaced in such a way that the O atoms are not directly connected to each other, preferably an alkyl or alkoxy group having 1 to 6 carbon atoms,

[0384] Z x and Z y Each independently represents -CH2CH2-, -CH=CH-, -CF2O-, -OCF2-, -CH2O-, -OCH2-, -CO-O-, -O-CO-, -C2F4-, -CF=CF-, -CH=CH-CH2O- or a single bond, preferably a single bond,

[0385] L 1-4 Each independently represents F, Cl, OCF3, CF3, CH3, CH2F, CHF2.

[0386] Preferably, L 1 and L 2 Both represent F, or L 1 and L 2 One of them represents F and the other represents Cl, or L 3 and L 4 Both represent F, or L 3 and L 4 One of represents F and the other represents Cl.

[0387] The compound of formula CY is preferably selected from the group consisting of the following subformulae:

[0388]

[0389]

[0390]

[0391]

[0392]

[0393] Where a represents 1 or 2, alkyl and alkyl * Each independently of one another represents a straight-chain alkyl radical having 1 to 6 C atoms, a cyclopentyl radical or a cyclopropylmethyl radical, and alkenyl represents a straight-chain alkenyl radical having 2 to 6 C atoms, and (O) represents an oxygen atom or a single bond. Alkenyl preferably represents CH2=CH-, CH2=CHCH2CH2-, CH3-CH=CH-, CH3-CH2-CH=CH-, CH3-(CH2)2-CH=CH-, CH3-(CH2)3-CH=CH- or CH3-CH=CH-(CH2)2-.

[0394] The compound of formula PY is preferably selected from the group consisting of the following subformulae:

[0395]

[0396]

[0397]

[0398]

[0399] Among them, alkyl and alkyl * Each independently of one another represents a straight-chain alkyl radical having 1 to 6 C atoms, a cyclopentyl radical or a cyclopropylmethyl radical, and alkenyl represents a straight-chain alkenyl radical having 2 to 6 C atoms, and (O) represents an oxygen atom or a single bond. Alkenyl preferably represents CH2=CH-, CH2=CHCH2CH2-, CH3-CH=CH-, CH3-CH2-CH=CH-, CH3-(CH2)2-CH=CH-, CH3-(CH2)3-CH=CH- or CH3-CH=CH-(CH2)2-.

[0400] c) LC media, wherein component B) or the LC host mixture comprises one or more compounds of the formula:

[0401]

[0402] The various groups have the following meanings:

[0403] express

[0404] or

[0405] express or

[0406] R 3 and R 4 each independently of one another represents an alkyl radical having 1 to 12 C atoms, wherein one or two non-adjacent CH2 groups may be replaced by -O-, -CH=CH-, -CO-, -O-CO- or -CO-O- are replaced in such a way that the O atoms are not directly connected to each other,

[0407] Z yIt represents -CH2CH2-, -CH=CH-, -CF2O-, -OCF2-, -CH2O-, -OCH2-, -CO-O-, -O-CO-, -C2F4-, -CF=CF-, -CH=CH-CH2O- or a single bond, preferably a single bond.

[0408] The compound of formula ZK is preferably selected from the group consisting of the following subformulae:

[0409]

[0410]

[0411] Among them, alkyl and alkyl * each independently of one another represents a straight-chain alkyl radical having 1 to 6 C atoms, and alkenyl represents a straight-chain alkenyl radical having 2 to 6 C atoms. Alkenyl preferably represents CH2=CH-, CH2=CHCH2CH2-, CH3-CH=CH-, CH3-CH2-CH=CH-, CH3-(CH2)2-CH=CH-, CH3-(CH2)3-CH=CH- or CH3-CH=CH-(CH2)2-.

[0412] Especially preferred are compounds of formula ZK1.

[0413] Particularly preferred compounds of formula ZK are selected from the following subformulae:

[0414]

[0415]

[0416] Among them, propyl, butyl and pentyl are straight-chain groups.

[0417] Most preferred are compounds of formula ZK1a and ZK3b.

[0418] d) LC media, wherein component B) or the LC host mixture additionally comprises one or more compounds of the formula:

[0419]

[0420] where the individual radicals have the following meanings on each occurrence, identically or differently:

[0421] R 5 and R 6each independently of one another represents an alkyl radical having 1 to 12 C atoms, wherein furthermore one or two non-adjacent CH2 groups may be replaced by -O-, -CH=CH-, -CO-, -OCO- or -COO- in such a way that the O atoms are not directly connected to one another, preferably an alkyl radical or alkoxy radical having 1 to 6 C atoms,

[0422] express or

[0423] express or and e means 1 or 2.

[0424] The compound of formula DK is preferably selected from the group consisting of the following subformulae:

[0425]

[0426]

[0427]

[0428] Among them, alkyl and alkyl * each independently of one another represents a straight-chain alkyl radical having 1 to 6 C atoms, and alkenyl represents a straight-chain alkenyl radical having 2 to 6 C atoms. Alkenyl preferably represents CH2=CH-, CH2=CHCH2CH2-, CH3-CH=CH-, CH3-CH2-CH=CH-, CH3-(CH2)2-CH=CH-, CH3-(CH2)3-CH=CH- or CH3-CH=CH-(CH2)2-.

[0429] e) LC media, wherein component B) or the LC host mixture additionally comprises one or more compounds of the formula:

[0430]

[0431] The various groups have the following meanings:

[0432] express

[0433] or

[0434] wherein at least one ring F is different from cyclohexylene,

[0435] f means 1 or 2,

[0436] R 1 and R2 each independently of one another represents an alkyl radical having 1 to 12 C atoms, wherein one or two non-adjacent CH2 groups may additionally be replaced by -O-, -CH=CH-, -C≡C-, -CO-, -OCO- or -COO- are substituted in such a way that the O atoms are not directly connected to each other,

[0437] Z x represents -CH2CH2-, -CH=CH-, -CF2O-, -OCF2-, -CH2O-, -OCH2-, -CO-O-, -O-CO-, -C2F4-, -CF=CF-, -CH=CH-CH2O- or a single bond, preferably a single bond,

[0438] L 1 and L 2 Each independently represents F, Cl, OCF3, CF3, CH3, CH2F, CHF2.

[0439] Preferably, the group L 1 and L 2 All represent F, or group L 1 and L 2 One of represents F and the other represents Cl.

[0440] The compound of formula LY is preferably selected from the group consisting of the following subformulae:

[0441]

[0442]

[0443]

[0444] where R 1 have the meanings given above, alkyl represents a straight-chain alkyl radical having 1 to 6 C atoms, a cyclopentyl radical or a cyclopropylmethyl radical, (O) represents an oxygen atom or a single bond, and v represents an integer from 1 to 6. 1 Preferably represents straight-chain alkyl having 1 to 6 C atoms, cyclopentyl, cyclopropylmethyl, cyclopropyl, cyclobutyl or straight-chain alkenyl having 2 to 6 C atoms, in particular CH3, C2H5, n-C3H7, n-C4H9, n-C5H 11 , cyclo-C5H 11 , 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-.

[0445] f) LC media, wherein component B) or the LC host mixture additionally comprises one or more compounds selected from the group consisting of:

[0446]

[0447] Where alkyl represents C 1-6 Alkyl, L x represents H or F, and X represents F, Cl, OCF3, OCHF2 or OCH=CF2. Particular preference is given to compounds of formula G1 in which X represents F.

[0448] g) LC media, wherein component B) or the LC host mixture additionally comprises one or more compounds selected from the group consisting of:

[0449]

[0450]

[0451]

[0452] where R 5 With the above for R 1 One of the meanings given, alkyl means C 1-6 -alkyl, d represents 0 or 1, and z and m each independently represent an integer from 1 to 6. 5 Particularly preferred is C 1-6 -alkyl or -alkoxy or C 2-6 -alkenyl, d is preferably 1. The LC media according to the invention preferably comprise one or more compounds of the formulae indicated above in an amount of ≥ 5% by weight.

[0453] h) LC medium, wherein component B) or the LC host mixture additionally comprises one or more biphenyl compounds selected from the group consisting of:

[0454]

[0455] Among them, alkyl and alkyl * each independently of one another represents a straight-chain alkyl group having 1 to 6 C atoms, and alkenyl and alkenyl * Each independently of one another represents a straight-chain alkenyl radical having 2 to 6 C atoms. *Preferably it represents CH2=CH-, CH2=CHCH2CH2-, CH3-CH=CH-, CH3-CH2-CH=CH-, CH3-(CH2)2-CH=CH-, CH3-(CH2)3-CH=CH- or CH3-CH=CH-(CH2)2-.

[0456] The proportion of the biphenyls of the formulae B1 to B3 in the LC host mixture is preferably at least 3% by weight, in particular ≥5% by weight.

[0457] Compounds of formula B2 are particularly preferred.

[0458] The compounds of the formulae B1 to B3 are preferably selected from the group consisting of the following subformulae:

[0459]

[0460] Among them alkyl * represents an alkyl group having 1 to 6 C atoms. The medium according to the invention particularly preferably comprises one or more compounds of the formula B1a and / or B2c.

[0461] i) LC medium, wherein component B) or the LC host mixture additionally comprises one or more terphenyl compounds of the formula:

[0462]

[0463] where R 5 and R 6 Each independently has one of the meanings indicated above and

[0464] and Each independently represents: or

[0465] Among them L 5 represents F or Cl, preferably F, and L 6 represents F, Cl, OCF3, CF3, CH3, CH2F or CHF2, preferably F.

[0466] The compound of formula T is preferably selected from the group consisting of the following subformulae:

[0467]

[0468]

[0469]

[0470] wherein R represents a straight chain alkyl or alkoxy group having 1 to 7 carbon atoms, R* represents a straight-chain alkenyl group having 2 to 7 C atoms, (O) represents an oxygen atom or a single bond, and m represents an integer of 1 to 6. R * Preferably it represents CH2=CH-, CH2=CHCH2CH2-, CH3-CH=CH-, CH3-CH2-CH=CH-, CH3-(CH2)2-CH=CH-, CH3-(CH2)3-CH=CH- or CH3-CH=CH-(CH2)2-.

[0471] R preferably represents methyl, ethyl, propyl, butyl, pentyl, hexyl, methoxy, ethoxy, propoxy, butoxy or pentoxy.

[0472] The LC host mixture according to the present invention preferably comprises the terphenyl of formula T and preferred subformulae thereof, preferably in an amount of 0.5-30% by weight, preferably 1-20% by weight, in particular 2-10% by weight.

[0473] Compounds of the formulae T1, T2, T3 and T21 are particularly preferred, most preferred being T2. In these compounds, R preferably represents an alkyl group, also an alkoxy group, each having 1 to 5 C atoms.

[0474] Terphenyls are preferably used in the LC media according to the invention if the Δn value of the mixture is ≥0.1. Preferred LC media comprise 2-20% by weight of one or more terphenyl compounds of the formula T, preferably selected from compounds T1 to T22.

[0475] k) LC medium, wherein component B) or the LC host mixture additionally comprises one or more quaternary compounds selected from the group consisting of:

[0476]

[0477] in

[0478] R Q is alkyl, alkoxy, oxaalkyl or alkoxyalkyl having 1 to 9 C atoms, or alkenyl or alkenyloxy having 2 to 9 C atoms, all of which are optionally fluorinated,

[0479] X Q is F, Cl, a haloalkyl or alkoxy group having 1 to 6 C atoms, or a haloalkenyl or alkenyloxy group having 2 to 6 C atoms,

[0480] L Q1 To L Q6 are independently H or F, wherein L Q1 To L Q6 At least one of them is F.

[0481] Preferred compounds of formula Q are those wherein RQ These represent straight-chain alkyl radicals having 2 to 6 C atoms, very preferably ethyl, n-propyl or n-butyl.

[0482] Preferred compounds of formula Q are those wherein L Q3 and L Q4 is those of F. Further preferred compounds of formula Q are those wherein L Q3 , L Q4 and L Q1 and L Q2 One or two of them are F.

[0483] Preferred compounds of formula Q are those wherein X Q Those representing F or OCF3 (very preferably F).

[0484] The compound of formula Q is preferably selected from the following sub-formulas

[0485]

[0486]

[0487] where R Q has one of the meanings of the formula Q or one of its preferred meanings given above and below, and is preferably ethyl, n-propyl or n-butyl.

[0488] Particularly preferred are compounds of formula Q1, particularly wherein R Q Those that are n-propyl.

[0489] Preferably, the proportion of the compound of formula Q in the LC host mixture is from >0 to ≤5% by weight, very preferably from 0.1 to 2% by weight, most preferably from 0.2 to 1.5% by weight.

[0490] Preferably, the LC host mixture contains 1 to 5 compounds of formula Q, preferably 1 or 2.

[0491] Adding quaterphenyl compounds of formula Q to LC host mixtures can reduce ODF color shift while maintaining high UV absorption, enable fast and complete polymerization, enable strong and fast tilt angle generation, and increase the UV stability of the LC medium.

[0492] Furthermore, the addition of compounds of formula Q having positive dielectric anisotropy to LC media having negative dielectric anisotropy allows for better control of the values ​​of the dielectric constants ε|| and ε⊥, and in particular enables high values ​​of the dielectric constant ε|| to be achieved while keeping the dielectric anisotropy Δε constant, thereby reducing the kickback voltage and reducing image sticking.

[0493] 1) LC medium, wherein component B) or the LC host mixture additionally comprises one or more compounds of formula C:

[0494]

[0495] in

[0496] R C represents 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,

[0497] X C represents F, Cl, a haloalkyl or alkoxy group having 1 to 6 C atoms, or a haloalkenyl or alkenyloxy group having 2 to 6 C atoms,

[0498] L C1 , L C2 represents H or F independently of each other, where L C1 and L C2 At least one of them is F.

[0499] Preferred compounds of formula C are those wherein R C These represent straight-chain alkyl radicals having 2 to 6 C atoms, very preferably ethyl, n-propyl or n-butyl.

[0500] Preferred compounds of formula C are those wherein L C1 and L C2 Those are F.

[0501] Preferred compounds of formula C are those wherein X C Those representing F or OCF3 (very preferably F).

[0502] Preferred compounds of formula C are selected from the following

[0503]

[0504] where R C has one of the meanings of formula C or one of its preferred meanings given above and below, and is preferably ethyl, n-propyl or n-butyl, very preferably n-propyl.

[0505] Preferably, the proportion of the compound of formula C in the LC host mixture is >0 to ≤10% by weight, very preferably 0.1 to 8% by weight, most preferably 0.2 to 5% by weight.

[0506] Preferably, the LC host mixture contains 1 to 5 compounds of formula C, preferably 1, 2 or 3 compounds.

[0507] Adding a compound of Formula C with positive dielectric anisotropy to an LC medium with negative dielectric anisotropy allows for better control of the values ​​of the dielectric constants ε|| and ε⊥. In particular, it is possible to achieve high values ​​of the dielectric constant ε|| while maintaining a constant dielectric anisotropy Δε, thereby reducing kickback voltage and image sticking. Furthermore, the addition of the compound of Formula C can reduce the viscosity and response time of the LC medium.

[0508] m) LC medium, wherein component B) or the LC host mixture additionally comprises one or more compounds selected from the group consisting of:

[0509]

[0510]

[0511] where R 1 and R 2 have the meanings indicated above and preferably each independently of one another represent straight-chain alkyl having 1 to 6 C atoms or straight-chain alkenyl having 2 to 6 C atoms.

[0512] Preferred media comprise one or more compounds selected from the group consisting of formulae O1, O3 and O4.

[0513] n) LC medium, wherein component B) or the LC host mixture additionally comprises one or more compounds of the formula:

[0514]

[0515] in express

[0516]

[0517]

[0518] R 9 represents H, CH3, C2H5 or n-C3H7, (F) represents an optional fluorine substituent, and q represents 1, 2 or 3, and R 7 With R 1 Within the meanings indicated, preferably the amount is >3% by weight, in particular ≥5% by weight, very particularly preferably 5 to 30% by weight.

[0519] Particularly preferred compounds of formula FI are selected from the group consisting of the following subformulae:

[0520]

[0521]

[0522] where R 7Preferably represents a straight chain alkyl group, and R 9 represents CH3, C2H5 or n-C3H7. Particularly preferred are compounds of formula FI1, FI2 and FI3.

[0523] o) LC medium, wherein component B) or the LC host mixture additionally comprises one or more compounds selected from the group consisting of:

[0524]

[0525] where R 8 With R 1 The meanings indicated, and alkyl denotes straight-chain alkyl having 1-6 C atoms.

[0526] p) LC medium, wherein component B) or the LC host mixture additionally comprises one or more compounds containing tetrahydronaphthyl or naphthyl units, for example compounds selected from the group consisting of:

[0527]

[0528]

[0529] in

[0530] R 10 and R 11 each independently of one another represents an alkyl radical having 1 to 12 C atoms, wherein furthermore one or two non-adjacent CH2 groups may be replaced by -O-, -CH=CH-, -CO-, -OCO- or -COO- in such a way that the O atoms are not directly connected to one another, preferably an alkyl radical or alkoxy radical having 1 to 6 C atoms,

[0531] And R 10 and R 11 preferably represents a straight-chain alkyl or alkoxy radical having 1 to 6 C atoms, or a straight-chain alkenyl radical having 2 to 6 C atoms, and

[0532] Z 1 and Z 2 Each independently represents -C2H4-, -CH=CH-, -(CH2)4-, -(CH2)3O-, -O(CH2)3-, -CH=CH-CH2CH2-, -CH2CH2CH=CH-, -CH2O-, -OCH2-, -CO-O-, -O-CO-, -C2F4-, -CF=CF-, -CF=CH-, -CH=CF-, -CH2- or a single bond.

[0533] q) LC media, wherein component B) or the LC host mixture additionally comprises one or more difluorodibenzochromans and / or chromans of the following formula:

[0534]

[0535] in

[0536] R 11 and R 12 Each independently has the above 11 One of the meanings pointed out is

[0537] Ring M is trans-1,4-cyclohexylene or 1,4-phenylene,

[0538] Z m is -C2H4-, -CH2O-, -OCH2-, -CO-O- or -O-CO-,

[0539] c is 0, 1, or 2,

[0540] Preferably, the amount thereof is 3-20 wt%, particularly 3-15 wt%.

[0541] Particularly preferred compounds of formula BC, CR and RC are selected from the group consisting of the following subformulae:

[0542]

[0543]

[0544]

[0545]

[0546] Among them, alkyl and alkyl * each independently of one another represents a straight-chain alkyl group having 1 to 6 C atoms, (O) represents an oxygen atom or a single bond, c is 1 or 2, and alkenyl and alkenyl * Each independently of one another represents a straight-chain alkenyl radical having 2 to 6 C atoms. * Preferably it represents CH2=CH-, CH2=CHCH2CH2-, CH3-CH=CH-, CH3-CH2-CH=CH-, CH3-(CH2)2-CH=CH-, CH3-(CH2)3-CH=CH- or CH3-CH=CH-(CH2)2-.

[0547] Very particular preference is given to LC host mixtures comprising one, two or three compounds of the formula BC-2.

[0548] r) LC medium, wherein component B) or the LC host mixture additionally comprises one or more fluorinated phenanthrenes and / or dibenzofurans of the following formulae:

[0549]

[0550] where R 11 and R 12 Each independently has the above 11 b represents 0 or 1, L represents F, and r represents 1, 2, or 3.

[0551] Particularly preferred compounds of formula PH, BF and BS are selected from the group consisting of the following subformulae:

[0552]

[0553] wherein R and R' each independently of one another represent a straight-chain alkyl group, a cyclopentyl group, a cyclopentylmethoxy group, a cyclopropylmethoxy group or an alkoxy group having 1 to 7 C atoms.

[0554] s) LC medium, wherein component B) or the LC host mixture additionally comprises one or more monocyclic compounds of the formula

[0555]

[0556] in

[0557] R 1 and R 2 each independently of one another represents an alkyl radical having 1 to 12 C atoms, wherein furthermore one or two non-adjacent CH2 groups may be replaced by -O-, -CH=CH-, -CO-, -OCO- or -COO- in such a way that the O atoms are not directly connected to one another, preferably an alkyl radical or an alkoxy radical having 1 to 6 C atoms,

[0558] L 1 and L 2 Each independently represents F, Cl, OCF3, CF3, CH3, CH2F, CHF2.

[0559] Preferably, L 1 and L 2 Both mean F or L 1 and L 2 One of them represents F and the other represents Cl,

[0560] The compound of formula Y is preferably selected from the group consisting of the following subformulae:

[0561]

[0562]

[0563] Among them, Alkyl and Alkyl* Each independently of one another represents a straight-chain alkyl radical having 1 to 6 C atoms, Alkoxy represents a straight-chain alkoxy radical having 1 to 6 C atoms, Alkenyl and Alkenyl * Each independently represents a straight-chain alkenyl group having 2 to 6 C atoms, and O represents an oxygen atom or a single bond. * Preferably, it represents CH2=CH-, CH2=CHCH2CH2-, CH3-CH=CH-, CH3-CH2-CH=CH-, CH3-(CH2)2-CH=CH-, CH3-(CH2)3-CH=CH- or CH3-CH=CH-(CH2)2-.

[0564] Particularly preferred compounds of formula Y are selected from the group consisting of the following subformulae:

[0565]

[0566] Alkoxy preferably represents a straight-chain alkoxy group having 3, 4 or 5 C atoms.

[0567] t) LC medium which, apart from the polymerisable compounds as described above and below, does not comprise compounds containing terminal vinyloxy groups (-O-CH=CH2).

[0568] u) LC medium in which component B) or the LC host mixture comprises 1 to 8, preferably 1 to 5, compounds of the formula CY1, CY2, PY1 and / or PY2. The proportion of these compounds in the overall LC host mixture is preferably 5 to 60%, particularly preferably 10 to 35%. The content of these individual compounds is preferably in each case 2 to 20%.

[0569] v) LC medium in which component B) or the LC host mixture comprises one or more, preferably 1 to 8, more preferably 1 to 5, compounds of the formula CY9, CY10, PY9 and / or PY10. The proportion of these compounds in the overall LC host mixture is preferably 5 to 60%, particularly preferably 10 to 35%. The content of these individual compounds is preferably in each case 2 to 20%.

[0570] w) LC medium in which component B) or the LC host mixture comprises 1 to 10, preferably 1 to 8, compounds of the formula ZK, in particular compounds of the formula ZK1, ZK2 and / or ZK3. The proportion of these compounds in the overall LC host mixture is preferably 3 to 25%, particularly preferably 5 to 45%. The content of these individual compounds is preferably in each case 2 to 25%.

[0571] x) LC media in which the proportion of compounds of the formulae CY, PY and ZK in the overall LC host mixture is greater than 70%, preferably greater than 80%.

[0572] y) LC medium in which component B) or the LC host mixture contains one or more, preferably 1 to 5, compounds selected from the group consisting of formulae PY1 to PY8 (very preferably formula PY2). The proportion of these compounds in the overall LC host mixture is preferably 1 to 30%, particularly preferably 2 to 20%. The content of these individual compounds is preferably in each case 1 to 20%.

[0573] The combination of the compounds of the preferred embodiments described above with the polymerized compounds described above leads, in the LC media according to the invention, to low threshold voltages, low rotational viscosities, and very good low-temperature stability, while also exhibiting high clearing points and high HR values, and allows for the rapid establishment of particularly low pretilt angles in PSA displays. In particular, the LC media exhibit significantly shorter response times, in particular also the gray-to-gray response times, in PSA displays compared to the media of the prior art.

[0574] The LC media and LC host mixtures according to the invention preferably have a nematic phase range of at least 80 K, particularly preferably at least 100 K, and a rotational viscosity at 20° C. of ≤250 mPa·s, preferably ≤200 mPa·s.

[0575] In a VA-type display according to the invention, the molecules in the layer of the LC medium are aligned perpendicular to the electrode surface (homeotropically) or have a tilted homeotropic alignment in the off state. When a voltage is applied to the electrodes, the LC molecules realign with their longitudinal molecular axes parallel to the electrode surface.

[0576] The LC media according to the invention, which are used in particular in displays of the PS-VA, PS-UB-FFS and SA-VA type and which, according to a first preferred embodiment, are based on compounds having a negative dielectric anisotropy, preferably have a negative dielectric anisotropy Δε at 20° C. and 1 kHz of from −0.5 to −10, in particular from −2.5 to −7.5.

[0577] The birefringence Δn of the LC media according to the invention for use in displays of the PS-VA, PS-UB-FFS and SA-VA type is preferably below 0.16, particularly preferably from 0.06 to 0.14, very particularly preferably from 0.07 to 0.12.

[0578] In an OCB-type display according to the invention, the molecules in the layer of the LC medium have a "bend" alignment. Upon application of a voltage, a realignment of the LC molecules occurs with the longitudinal molecular axis perpendicular to the electrode surface.

[0579] The birefringence Δn of the LC media according to the invention for use in displays of the PS-OCB type is preferably from 0.14 to 0.22, particularly preferably from 0.16 to 0.22.

[0580] The LC media according to the invention may also contain other additives known to those skilled in the art and described in the literature, such as polymerization initiators, inhibitors, stabilizers, surfactants, or chiral dopants. These substances may be polymerizable or non-polymerizable. Polymerizable additives are therefore classified as polymerizable components or component A). Non-polymerizable additives are therefore classified as non-polymerizable components or component B).

[0581] In a preferred embodiment, the LC medium contains one or more chiral dopants, preferably in a concentration of 0.01 to 1%, very preferably 0.05 to 0.5%. The chiral dopant is preferably selected from the compounds of Table B below, very preferably selected from R- or S-1011, R- or S-2011, R- or S-3011, R- or S-4011 and R- or S-5011.

[0582] In another preferred embodiment, the LC medium comprises the racemate of one or more chiral dopants, which are preferably selected from the chiral dopants mentioned in the previous paragraph.

[0583] Furthermore, it is possible to add, for example, 0 to 15% by weight of pleochroic dyes to the LC medium, in addition to nanoparticles, conductive salts, preferably ethyldimethyldodecyl 4-hexyloxyammonium benzoate, tetrabutylammonium tetraphenylborate or complex salts of crown ethers (see, for example, Haller et al., Mol. Cryst. Liq. Cryst. 24 , 249-258 (1973)) for improving the electrical conductivity or adding substances for changing the orientation, viscosity and / or dielectric anisotropy of the nematic phase. Such substances are described, for example, in DE-A 22 09 127, 2240 864, 23 21 632, 23 38 281, 24 50 088, 26 37 430 and 28 53 728.

[0584] The individual components of the preferred embodiments a) to z) of the LC media according to the invention are known, or the methods for preparing them can be derived from the prior art by a person skilled in the relevant art, since they are based on standard methods described in the literature. For example, the corresponding compounds of the formula CY are described 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.

[0585] The LC media that can be used according to the invention are prepared in a conventional manner, for example by mixing one or more of the above-mentioned compounds with one or more polymerizable compounds as defined above, and optionally with other liquid-crystalline compounds and / or additives. Typically, the desired amount of the component used in smaller amounts is dissolved in the component that makes up the main composition, advantageously at elevated temperature. It is also possible to mix the solutions of the components in an organic solvent, such as acetone, chloroform or methanol, and remove the solvent again after thorough mixing, for example by distillation. The present invention also relates to a process for the preparation of the LC media according to the invention.

[0586] It goes without saying to the person skilled in the art that the LC media according to the invention can also comprise compounds in which H, N, O, Cl, F are replaced by corresponding isotopes, for example deuterium.

[0587] The following examples illustrate the present invention without limiting it. However, they show preferred mixture concepts and preferably used compounds and their corresponding concentrations and their combinations with one another to those skilled in the art. In addition, the examples illustrate obtainable properties and property combinations.

[0588] Preferred mixture compositions are shown in Tables A1 and A2 below. The compounds shown in Table A1 are particularly suitable for use in LC mixtures with positive dielectric anisotropy. The compounds shown in Table A2 are particularly suitable for use in LC mixtures with negative dielectric anisotropy.

[0589] Table A1

[0590] In Table A1, m and n are each independently 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 Meaning C m H 2m+1 or OC m H 2m+1 .

[0591]

[0592]

[0593]

[0594]

[0595]

[0596]

[0597]

[0598]

[0599]

[0600]

[0601] Table A2

[0602] In Table A2, m and n are each independently 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 Meaning C m H 2m+1 or OC m H 2m+1 .

[0603]

[0604]

[0605]

[0606]

[0607]

[0608]

[0609]

[0610]

[0611]

[0612]

[0613]

[0614]

[0615]

[0616]

[0617]

[0618]

[0619]

[0620]

[0621]

[0622]

[0623]

[0624]

[0625] In a preferred embodiment of the invention, the LC media according to the invention, especially those having negative dielectric anisotropy, comprise one or more compounds selected from the group consisting of the compounds from Table A2.

[0626] Table B

[0627] Table B shows possible chiral dopants that can be added to the LC media according to the invention.

[0628]

[0629]

[0630] 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 dopant. The LC medium preferably comprises one or more dopants selected from the group consisting of the compounds from Table B.

[0631] Table C

[0632] Table C shows possible stabilizers which can be added to the LC media according to the invention. wherein n represents an integer from 1 to 12, preferably 1, 2, 3, 4, 5, 6, 7 or 8.

[0633]

[0634]

[0635]

[0636]

[0637]

[0638]

[0639] The LC medium preferably comprises 0 to 10% by weight, in particular 1 ppm to 5% by weight, particularly preferably 1 ppm to 1% by weight, of stabilizers. The LC medium preferably comprises one or more stabilizers selected from the group consisting of compounds from Table C.

[0640] Table D

[0641] Table D shows self-aligning additives for homeotropic alignment which can be used together with the polymerisable compounds of formula I in the LC media according to the invention.

[0642]

[0643]

[0644]

[0645]

[0646]

[0647]

[0648]

[0649]

[0650]

[0651] In a preferred embodiment, the LC medium, SA-VA display according to the invention comprises one or more SA additives selected from the group consisting of formulae SA-1 to SA-38, preferably SA-14 to SA-36, very preferably SA-20 to SA-28, most preferably SA-20 or SA-22, in combination with one or more RMs of formula I and one or more RMs of formula II. Very preferred are the polymerizable compounds RM-2 and RM-3 of Synthesis Example 1 below in combination with SA additives of formulae SA-20 to SA-28, very preferably SA-20 or SA-22. DETAILED DESCRIPTION

[0652] Example

[0653] The following examples illustrate the present invention without limiting it. However, they show preferred mixture concepts and preferably used compounds and their corresponding concentrations and their combinations with one another to those skilled in the art. In addition, the examples illustrate obtainable properties and property combinations.

[0654] In addition, the following abbreviations and symbols are used:

[0655] V0 represents the capacitive threshold voltage [V] at 20°C,

[0656] n e represents the extraordinary refractive index at 20°C and 589 nm,

[0657] n o represents the ordinary refractive index at 20°C and 589 nm,

[0658] Δn represents the optical anisotropy at 20°C and 589 nm,

[0659] ε ⊥ represents the dielectric constant perpendicular to the director at 20°C and 1kHz,

[0660] ε || represents the dielectric constant parallel to the director at 20°C and 1kHz,

[0661] Δε represents the dielectric anisotropy at 20°C and 1 kHz,

[0662] cl.p., T(N,I) represents the clearing point [℃],

[0663] γ1 represents the rotational viscosity at 20°C [mPa·s],

[0664] K1 represents the elastic constant [pN] of the “stretching” deformation at 20°C,

[0665] K2 represents the elastic constant of "torsion" deformation at 20°C [pN],

[0666] K3 represents the elastic constant [pN] of "bending" deformation at 20°C.

[0667] Unless expressly stated otherwise, all concentrations in the present application are given as percentages by weight and relate to the respective entire mixture, comprising all solid or liquid-crystalline components (without solvent).

[0668] Unless otherwise indicated, all temperature values ​​stated in this application, such as melting point T(C, N), the transition from the smectic phase (S) to the nematic phase (N) T(S, N), and the clearing point T(N, I), are expressed in degrees Celsius (°C). Mp = melting point, cl.p. = clearing point. Furthermore, C = liquid crystal phase, N = nematic phase, S = smectic phase, and I = isotropic phase. The values ​​between these symbols represent transition temperatures.

[0669] 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, with Δn measured at 589 nm and Δε measured at 1 kHz, unless expressly stated otherwise in each case.

[0670] The term "threshold voltage" as used in the present invention relates to the capacitive threshold (V0), which is also referred to as the Freedericks threshold unless otherwise stated. In the embodiments, the optical threshold is also typically for a relative contrast ratio of 10% (V 10 ) given.

[0671] Unless otherwise stated, the process for polymerising the polymerisable compounds in a PSA display as described above and below is carried out at a temperature at which the LC medium exhibits a liquid crystalline phase, preferably a nematic phase, and most preferably at room temperature.

[0672] Unless otherwise stated, the methods for preparing the test cells and measuring their electro-optical and other properties were performed by the methods described below or methods analogous thereto.

[0673] The display used to measure the capacitive threshold voltage consisted of two plane-parallel glass outer plates separated by 25 μm, each with an electrode layer on the inside and an unrubbed polyimide alignment layer on top, which resulted in homeotropic edge alignment of the liquid crystal molecules.

[0674] The PSVA display or PSVA test cell used to measure the tilt angle consists of two plane-parallel glass outer plates separated by 4 μm, each with an electrode layer on the inside and a polyimide alignment layer on top, where the two polyimide layers are rubbed antiparallel to each other and result in homeotropic edge alignment of the liquid crystal molecules.

[0675] The polymerizable compound is polymerized in the display or test box by irradiating it with UV light of a defined intensity for a predetermined time while applying a voltage to the display (typically 10 to 30 V AC, 1 kHz). In the examples, unless otherwise stated, a metal halide lamp and a 100 mW / cm 2 The intensity of was used for the polymerization. This intensity was measured using a standard meter (high-end Hoenle UV-meter with UV sensor).

[0676] The tilt angle was determined using a Mueller Matrix Polarimeter "AxoScan" from Axometrics. Low values ​​here (ie large deviations from an angle of 90°) correspond to large tilts.

[0677] Unless otherwise stated, the term "tilt angle" means the angle between the LC director and the substrate, and "LC director" means the preferred orientation direction of the optical principal axis of the LC molecules (corresponding to the molecular long axis in the case of rod-shaped, uniaxially positively birefringent LC molecules) in a layer of LC molecules with uniform orientation.

[0678] Polymerizable additives for polymerizable media:

[0679]

[0680]

[0681] RM-2 was prepared as follows.

[0682] Synthesis Example 1

[0683] 1.1 Synthesis of 4-[4-(3-hydroxyphenyl)-5-(2-propenyl)-phenyl]phenol 1

[0684]

[0685] 74.3g (537.5mmol) of K2CO3 was dissolved in 220ml of water, and then 38.9g (282mmol) of 4-hydroxyphenylboronic acid and 37.1g (134mmol) of 1,3-dibromo-5-(2-propenyl)benzene (CAS 874504-14-0) dissolved in 350ml of THF were added to the solution. The mixture was degassed three times with argon, and 203mg (5.375mmol) of CataCXium A and 246mg (2.69mmol) of tris (dibenzylideneacetone) dipalladium (0) were added. The reaction mixture was refluxed for 1 hour, cooled to room temperature, and diluted with water and MTBE. The mixture was filtered and the layers were separated. The aqueous layer was extracted with MTBE, and the combined organic layers were washed with ammonium chloride solution, brine, dried over Na2SO4, and evaporated under vacuum to obtain the product. The crude product was filtered on silica gel using ethyl acetate (EE) and heptane (3:1 to 1:1) and the product-containing fractions were combined and evaporated in vacuo to give the product as a pale yellow solid.

[0686] 1. Synthesis of 2-[4-[4-[3-(2-methylprop-2-enoyloxy)phenyl]-5-(2-propenyl)-phenyl]phenyl]2-methylprop-2-enoate 2

[0687]

[0688] 32.6 g (113.1 mmol) of diol 1 were dissolved in 720 ml of dichloromethane. 29.9 g (248.2 mmol) of methacrylic acid and 2.76 g (122.1 mmol) of 4-(dimethylamino)-pyridine were added, and the mixture was cooled to 5°C. 53.0 g (341 mmol) of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide were then added dropwise at a maximum temperature of 10°C, and the mixture was stirred at room temperature for 16 hours. The mixture was evaporated under vacuum, dissolved in 2 liters of dichloromethane, and filtered over silica gel. The product-containing fractions were combined and evaporated under vacuum to give the product 2 as an amorphous solid (decomposition >125°C).

[0689] The following compounds were synthesized similarly to Synthesis Example 1 and according to literature procedures:

[0690]

[0691]

[0692] Mixture Examples

[0693] polymerizable mixture

[0694] The polymerisable mixture according to the present invention is prepared by adding a polymerisable compound and a polymerisable self-aligning additive to a nematic LC host mixture. Other additives such as stabilisers may optionally be added or already included as additives in the mixture components.

[0695] The nematic LC host mixture was formulated as follows. Unless otherwise stated, the dielectric anisotropy Δε is negative and the percentages are in weight %:

[0696] The main mixture N1 was prepared as follows:

[0697]

[0698]

[0699] Main mixture N2

[0700]

[0701] Main mixture N3

[0702]

[0703]

[0704] Main mixture N4

[0705]

[0706] Main mixture N5

[0707]

[0708]

[0709] Main mixture N6

[0710]

[0711] Main mixture N7

[0712]

[0713]

[0714] Main mixture N8

[0715]

[0716] Main mixture N9

[0717]

[0718]

[0719] Main mixture N10

[0720]

[0721] Main mixture N11

[0722]

[0723]

[0724] Main mixture N12

[0725]

[0726] Main mixture N13

[0727]

[0728]

[0729] Main mixture N14

[0730]

[0731] Main mixture N15

[0732]

[0733] Main mixture N16

[0734]

[0735]

[0736] Main mixture N17

[0737]

[0738] Main mixture N18

[0739]

[0740]

[0741] Main mixture N19

[0742]

[0743] Main mixture N20

[0744]

[0745]

[0746] Main mixture N21

[0747]

[0748]

[0749] Main mixture N22

[0750]

[0751] Main mixture N23

[0752]

[0753]

[0754] Main mixture N24

[0755]

[0756] Main mixture N25

[0757]

[0758]

[0759] Main mixture N26

[0760]

[0761] Main mixture N27

[0762]

[0763]

[0764] Main mixture N28

[0765]

[0766]

[0767] Main mixture N29

[0768]

[0769] Main mixture N30

[0770]

[0771]

[0772] Main mixture N31

[0773]

[0774] Main mixture N32

[0775]

[0776]

[0777] Main mixture N33

[0778]

[0779] Main mixture N34

[0780]

[0781] Main mixture N35

[0782]

[0783] Main mixture N36

[0784]

[0785] Main mixture N37

[0786]

[0787] Main mixture N38

[0788]

[0789] Main mixture N39

[0790]

[0791]

[0792] Main mixture N40

[0793]

[0794] Main mixture N41

[0795]

[0796]

[0797] Main mixture N42

[0798]

[0799] Prior to or during the addition of the polymerizable additive, the bulk mixture is advantageously stabilized. For example, 0.01 wt. % Irganox-1076(R) is added to the bulk. Additionally, the polymerizable mixture is optionally stabilized with 0.015 wt. % STABILIX(R). Other optional stabilizers are disclosed in Table C.

[0800] Mixture Example P1

[0801] A polymerizable mixture P1 according to the present invention was prepared by adding 0.3% RM-1, 0.2% RM-2, 0.5% RM-3 and 0.9% SA-20 as polymerizable compounds to the nematic LC host mixture N1, and the mixture was homogenized.

[0802] Mixture Example P2

[0803] A polymerizable mixture P2 according to the present invention was prepared by adding 0.3% RM-1, 0.3% RM-2, 0.5% RM-3 and 1.5% SA-20 as polymerizable compounds to the nematic LC host mixture N1, and the mixture was homogenized.

[0804] Comparative mixture examples: polymerizable mixtures C1-C4

[0805] For comparison, polymerizable mixtures C1 and C2 were prepared by adding only RM-1 to the nematic LC host mixture N1 (0.6%, 0.9%, respectively).

[0806] Furthermore, a comparative polymerizable mixture C3 was prepared by adding 0.3% RM-1, 0.2% RM-2 and 0.9% SA-20 to the nematic LC host mixture N1.

[0807] Even further, a comparative polymerizable mixture C4 was prepared by adding 0.3% RM-1, 0.2% RM-2 and 1.5% SA-20 to the nematic LC host mixture N1.

[0808] Mixture Example P3

[0809] A polymerizable mixture P3 according to the present invention was prepared by adding 0.3% RM-1, 0.2% RM-2, 0.5% RM-3 and 0.9% SA-20 as polymerizable compounds to the nematic LC host mixture N1, and the mixture was homogenized.

[0810] Table 1 shows the compositions of some other polymerizable mixtures prepared similarly to the above procedure.

[0811] Table 1. Composition of other polymerizable mixtures

[0812] Mixture number P3 P4 P5 P6 P7 P8 LC body N1 N1 N2 N2 N1 N1 RM-1 0.3 0.3 0.3 0.3 0.3 0.3 RM-2 0.2 0.3 0.2 0.3 0.2 0.3 RM-3 0.5 0.5 0.5 0.5 0.5 0.5 SA-20 0.9 1.5 SA-22 0.9 1.5 SA-26 0.9 1.5

[0813] Mixture number P9 P10 P11 P12 P13 P14 LC body N42 N42 N42 N42 N42 N42 RM-1 RM-2 0.03 0.03 0.03 0.05 0.03 0.02 RM-3 0.3 0.3 0.3 0.3 0.25 0.25 SA-20 0.6 SA-22 0.6 0.6 0.6 0.6 SA-26 0.6

[0814] Application Example (Self-aligned PS-VA)

[0815] Each polymerizable mixture was filled into a PSA test cell and a test panel, the RM was polymerized under applied voltage, and several typical properties such as tilt generation, residual RM content, VHR under stress, image sticking, and tilt angle stability were measured.

[0816] By controlling the UV1 curing time, the tilt

[0817] The tilt generation behavior of the prepared LC medium was tested by polymerizing it in a test cell in a first UV polymerization step (UV1). The preferred duration of the UV1 step is 40 to 150 s. Within this range, the tilt generation can be sufficiently carefully controlled while maintaining a short cycle time for completing the polymerization step. The following Table 2.a / b describes the tilt generation behavior, where the symbols represent:

[0818] X: uncontrollable (tilt occurs too quickly and / or too strongly), Δ: acceptable, O: well controllable.

[0819] Table 2.a Tilt generation behavior during standard UV1 curing time (40-150s):

[0820]

[0821] All samples showed a vertical alignment with a certain degree of tilt. After about 50 (± 10) seconds of UV1 irradiation time, samples P1 and P2 according to the present invention achieved the desired tilt generation, which was just within the required time range. Comparative example C1 has a relatively thin polymer layer deposited on the electrode plane. For C2 and C5, the tilt generation was too strong and too fast to reach the target value. Conventional mixture C1 has an acceptable tilt generation. Comparative examples C3 and C4 achieved good tilt within the prescribed time range of UV1 irradiation, but the residual RM was very high (see below).

[0822] Table 2.b Tilt generation behavior during standard UV1 curing time (40-150s):

[0823]

[0824]

[0825] The samples showed homeotropic alignment after irradiation times in the desired time range and with a suitable angle of tilt within the desired range.

[0826] Residual RM measurement:

[0827] The content of unpolymerized RMs remaining in the mixture after UV exposure was determined (in wt%). The UV process was carried out under process conditions similar to those used in panel manufacturing (first UV curing for 40 to 120 s (Fe-I metal halide lamp); second UV final curing for 120 min (UV-C fluorescent lamp, 0.5 mW / cm 2 ).

[0828] For this purpose, the polymerizable mixture was filled into an electro-optical test cell with a cell gap of 3.3 μm made of AF glass coated with an ITO layer having a thickness of approximately 200 nm.

[0829] The test box is illuminated for a variable time period (1-2 hours) which is typically used for final cure.

[0830] After polymerization, the test cell was opened, the mixture was dissolved and rinsed out of the test cell with 2 ml of ethyl methyl ketone, and analyzed by high performance liquid chromatography (HPLC). The results are shown in Table 3.a / b.

[0831] Table 3.a - Residual RM content after 1 hour UV final curing (UV-C):

[0832] mixture RM-1 RM-2 RM-3 SA-20 P1 Not found Not found Not found <60ppm P2 Not found Not found Not found <60ppm C2 503ppm 166ppm Not added 429ppm

[0833] Table 3.b - Residual RM content after 2 hours UV final curing (UV-C):

[0834] mixture RM-1 RM-2 RM-3 SA-20 P1 Not found Not found Not found Not found P2 Not found Not found Not found Not found C2 66ppm Not found Not added 84ppm

[0835] As can be seen from Table 3.a / b, for the polymerizable mixtures according to the invention containing RM-3 in addition to RM-1 and RM-2, the residual RM content of RM-1, RM-2, and SA-20 is advantageously reduced after 1 hour. In contrast to conventional RM mixtures, mixtures P1 and P2 have no detectable residual RM content after 2 hours of final curing.

[0836] The modified UV-2 procedure (Table 3.c; first UV cure 40 to 120 seconds (Fe-I metal-halide lamp); second UV final cure 90 minutes (365 nm, 4 mW / cm 2 ,35℃)) obtained further results.

[0837] Table 3.c - Residual RM content after 2 hours UV final cure (365nm):

[0838] mixture RM-2 RM-3 SA-20 P9 24ppm Not found 28ppm

[0839] The mixture and resulting device are within the specification for PSA displays.

[0840] Determination of tilt stability:

[0841] The tilt stability of the mixtures was determined by comparing the tilt angles before and after stress conditions (60 Vpp, 200 Hz, 72 H). For mixture P9, the tilt stability was determined at a favorable level of 0.21°.

[0842] Determination of voltage holding ratio (VHR):

[0843] The reliability of the device using the medium according to the invention was also determined by the VHR value after the second UV step. Here, the first UV curing was carried out at 1 V / 0.6 Hz / 60° C. for 70-120 s (Fe-I metal-halide lamp); the second UV final curing was carried out for 90 minutes (365 nm, 4 mW / cm 2 ,35℃), measure VHR.

[0844] Mixture P9 showed a VHR value of 94.9%.For comparison, the mixture without additive RM-2 showed a lower VHR of 93%.

[0845] Image stiction under AC and DC power and backlight stress:

[0846] A series of test cells were driven at room temperature with 40 Vpp AC+DC for 14 hours with backlighting as a stress test. The grayscale levels of the test cells were then compared to a reference value that was not subjected to stress testing. The average difference in brightness was used as the image viscosity value (ISV). The ISV values ​​were compared to a comparison test cell using mixture C2.

[0847] The tendency of the mixtures according to the invention to exhibit image stiction after AC / DC stress conditions is significantly reduced compared to conventional mixtures. The reliability of the display panel is improved and this finding indicates an excellent stability of the orientation and tilt angle of the LC medium.

[0848] In summary, the above results show that the polymerisable LC media according to the present invention enable the production of LC panels with low residual RMs and excellent image sticking behaviour.Thus, the LC media according to the present invention show excellent performance.

[0849] Mixture Examples P15 to P54

[0850] Polymerizable mixtures P15 to P54 according to the present invention were prepared by adding 0.3% RM-1, 0.2% RM-2, 0.5% RM-3, and 0.9% SA-20 as polymerizable compounds to nematic LC host mixtures N3 to N42, respectively, and homogenizing each mixture. 0.015% STABILIX(R) was added to each host mixture.

[0851] Mixture Examples P55 to P94

[0852] Polymerizable mixtures P55 to P94 according to the present invention were prepared by adding 0.3% RM-1, 0.2% RM-2, 0.5% RM-3 and 0.9% SA-22 as polymerizable compounds to nematic LC host mixtures N3 to N42, respectively, and the respective mixtures were homogenized.

[0853] Mixture Examples P95 to P134

[0854] Polymerizable mixtures P95 to P134 according to the present invention were prepared by adding 0.3% RM-1, 0.2% RM-2, 0.5% RM-3 and 0.9% SA-26 as polymerizable compounds to nematic LC host mixtures N3 to N42, respectively, and the respective mixtures were homogenized.

Claims

1. A liquid crystal (LC) medium comprising: - a polymerizable component A) comprising a polymerizable compound, wherein at least the first one is a compound of formula I, wherein at least the second is a compound of formula II, and at least a third is a polymerizable self-aligning additive for homeotropic alignment of formula III, and - a liquid crystal LC component B) comprising one or more mesogenic or liquid crystal compounds, The various definitions are: where the individual radicals, independently of one another and identically or differently on each occurrence, have the following meanings: P is a polymerizable group, Sp is a spacer group or a single bond, R L is -CH3, -C2H5 or -CH2CH2CH3, r is independently 0, 1 or 2, s is 0 or 1, and L 1 , L 2 , L 3 is independently F, Cl or a linear, branched or cyclic alkyl group having 1 to 5 C atoms, wherein one or more non-adjacent CH2- groups are optionally replaced by -O-, -S-, -CO-, -CO-O-, -O-CO- or -O-CO-O- in such a way that the O and / or S atoms are not directly connected to each other, and wherein one or more H atoms are each optionally replaced by F or Cl, where the individual radicals, independently of one another and identically or differently on each occurrence, have the following meanings: P is a polymerizable group, Sp is a spacer group or a single bond, r is independently 0, 1 or 2, s is 0 or 1, and L 1 , L 2 is independently F, Cl or a linear, branched or cyclic alkyl group having 1 to 5 C atoms, wherein one or more non-adjacent CH2- groups are optionally replaced by -O-, -S-, -CO-, -CO-O-, -O-CO- or -O-CO-O- in such a way that the O and / or S atoms are not directly connected to each other, and wherein one or more H atoms are each optionally replaced by F or Cl, The MES-R a III in MES is a rod-shaped mesogenic group comprising two or more rings which are directly or indirectly linked to one another or fused to one another, wherein the rings are optionally substituted and which are optionally further substituted by one or more polymerizable groups which are linked directly to the MES or via a spacer, and R a is a polar anchoring group located at the end of the rod-shaped mesogen group MES, wherein the group R a A group comprising at least one carbon atom and at least one functional group selected from -OH, -SH, -COOH, -CHO or a primary or secondary amine, and which is optionally connected directly or via a spacer to R a The attached polymerizable group is substituted, At least one of MES or R a is substituted with at least one polymerizable group, directly or through a spacer.

2. LC medium according to claim 1, wherein the compound of formula I is selected from the group consisting of in P is a polymerizable group, Sp is a spacer group, and L 1 , L 3 Independently as defined in claim 1 for formula I.

3. LC medium according to claim 1 or 2, characterized in that In addition to the compounds of formula I, II and III, it also contains one or more other polymerizable compounds selected from the following formulae Wherein, each group has the following meaning: P 1 、P 2 and P 3 each independently of one another represents an acrylate group or a methacrylate group, Sp 1 、Sp 2 and Sp 3 each independently of one another represents a single bond or a spacer group, having one of the meanings as described above and below for Sp, R aa represents H, F, Cl, CN or a straight-chain or branched alkyl radical having 1 to 25 C atoms, wherein one or more further non-adjacent CH2 groups may also be replaced independently of one another 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 the O and / or S atoms are not directly connected to each other, and wherein in addition, one or more H atoms may be replaced by F, Cl, CN or P 1 -Sp 1 -Alternative, R 0 、R 00 each independently of one another and identically or differently on each occurrence represents H or alkyl having 1 to 12 C atoms, R y and R z Each independently represents H, F, CH3 or CF3, X 1 、X 2 and X 3 each independently represents -CO-O-, -O-CO- or a single bond, Z 1 Indicates -O-, -CO-, -C(R y R z )- or -CF2CF2-, Z 2 and Z 3 Each independently represents -CO-O-, -O-CO-, -CH2O-, -OCH2-, -CF2O-, -OCF2- or -(CH2) n -, where n is 2, 3, or 4, L, on each occurrence, identically or differently, represents F, Cl, CN or linear or branched, optionally mono- or polyfluorinated alkyl, alkoxy, alkenyl, alkynyl, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy radicals having 1 to 12 C atoms, L' and L" each independently represent H, F or Cl, r represents 0, 1, 2, 3 or 4, s represents 0, 1, 2 or 3, t represents 0, 1 or 2, x represents 0 or 1.

4. LC medium according to claim 1 or 2, wherein in formulae I, II and III, P represents an acrylate group or a methacrylate group.

5. LC medium according to claim 1 or 2, wherein the self-aligning additive for vertical alignment is of formula IIIa R 1 - [A 2 -Z 2 ] m -A 1 -R a IIIa in A 1 , A 2 each independently of one another represents an aromatic, heteroaromatic, alicyclic or heterocyclic radical, which may also contain fused rings and which may also be mono- or polysubstituted by radicals L or -Sp-P, L in each case independently of one another represents H, F, Cl, Br, I, -CN, -NO2, -NCS, -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 may each be replaced by F or Cl, P represents a polymerizable group, Sp represents a spacer group or a single bond, Z 2 represents, 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 -, -CF2CH2-, -CH2CF2-, -(CF2) n1 -, -CH=CH-, -CF=CF-, -C≡C-, -CH=CH-COO-, -OCO-CH=CH-, -(CR 0 R 00 ) n1 -, -CH(-Sp-P)-, -CH2CH-(-Sp-P)- or -CH(-Sp-P)CH(-Sp-P)-, n1 means 1, 2, 3 or 4, m means 1, 2, 3, 4 or 5, R 0 represents in each case, independently of one another, an alkyl radical having 1 to 12 C atoms, R 00 represents in each case, independently of one another, H or an alkyl radical having 1 to 12 C atoms, R 1 independently of one another represent H, halogen, straight-chain, branched or cyclic alkyl having 1 to 25 C atoms, wherein in addition one or more non-adjacent CH2 groups may each be -C≡C-, -CH=CH-, -O-, -S-, -CO-, -CO-O-, -O-CO- or -O-CO-O- are replaced in such a way that the O and / or S atoms are not directly connected to one another, and wherein in addition one or more H atoms may each be replaced by F or Cl, or -Sp-P group, and R a represents a polar anchoring group as defined in claim 1.

6. The liquid crystal medium according to claim 1 , wherein the self-aligning additive has an anchoring group R selected from the following formula a in p means 1 or 2, q represents 2, 3 or 4, wherein each group may be the same or different, B represents a substituted or unsubstituted ring system or a condensed ring system, Y independently represents -O-, -S-, -C(O)-, -C(O)O-, -OC(O)-, -NR 11 - or single key, o represents 0 or 1, X 1 independently represent H, alkyl, fluoroalkyl, OH, NH2, NHR 11 ,NR 11 2, -PO(OR 11 )2,-SO2R 11 , -OR 11 , C(O)OH, P or -CHO, At least one group X 1 represents a group selected from -OH, -NH2, NHR 11 ,-PO(OR 11 )2,-SO2R 11 , C(O)OH and -CHO groups, Z 1 are independently -(CO)-CH2(CO)OCH3, -(CO)-CH2(CO)-(C=CH2)-OCH3, - (CO)-CH2(CO)-(CH=CH)-OCH3, -(CO)-(CO)OCH3, -CH2-(CO)-(CO)OCH3, -(CO)-CH3, -(CO)-CH2(CO)-(CH2CH2)-OCH3, P is a polymerizable group, R 11 represents an alkyl group having 1 to 12 C atoms, R 12 represents H, an alkyl group having 1 to 12 C atoms, P or X 1 , Sp a , Sp c , Sp d each independently of one another represents a spacer group or a single bond, and Sp b represents a tri- or tetravalent group.

7. The liquid crystal medium according to claim 1 or 2, wherein the self-aligning additive for homeotropic alignment is a compound selected from the group consisting of formulae III-A to III-D, where R 1 , R a , A 2 , Z 2 , Sp and P have the meanings defined for formula IIIa in claim 5, L 1 As defined in claim 3, m is 1, 2, 3 or 4, and r1 is 0, 1, 2, 3, or 4.

8. LC medium according to claim 1 or 2, characterized in that One or more compounds of formula II are selected from the following Where P and L 1 As defined in formula II as claimed in claim 1, and Sp is a spacer group.

9. LC medium according to claim 1 or 2, characterized in that It additionally comprises a polymerizable compound selected from the structure 10. LC medium according to claim 1 or 2, characterized in that It comprises one or more compounds of formula CY and / or PY: The various groups have the following meanings: a means 1 or 2, b represents 0 or 1, express R 1 and R 2 each independently of one another represents an alkyl radical having 1 to 12 C atoms, wherein one or two non-adjacent CH2 groups may also be replaced by -O-, -CH=CH-, -C≡C-, -CO-, -O-CO- or -CO-O- are replaced in such a way that the O atoms are not directly connected to each other, Z x represents -CH=CH-, -CH2O-, -OCH2-, -CF2O-, -OCF2-, -O-, -CH2-, -CH2CH2- or a single bond, L 1-4 Each independently represents F, Cl, OCF3, CF3, CH3, CH2F, CHF2.

11. LC medium according to claim 1 or 2, characterized in that It comprises one or more compounds selected from the group consisting of formula CY9, CY10, PY9 and / or PY10 Among them, alkyl and alkyl * each independently of one another represents cyclopentyl, cyclopropylmethyl or a straight-chain alkyl radical having 1 to 6 C atoms.

12. LC medium according to claim 1 or 2, characterized in that It contains one or more compounds of the following formula: The various groups have the following meanings: express express R 3 and R 4 each independently of one another represents an alkyl group having 1 to 12 C atoms, furthermore one or two non-adjacent CH2 groups may be replaced by -O-, -CH=CH-, -CO-, -O-CO- or -CO-O- in such a way that the O atoms are not directly connected to one another, Z y Indicates -CH2CH2-, -CH=CH-, -CF2O-, -OCF2-, -CH2O-, -OCH2-, -COO-, -OCO-, -C2F4-, -CF=CF- or a single bond.

13. LC medium according to claim 1 or 2, characterized in that The polymerizable compounds of formula I, II and III are polymerized.

14. Process for the preparation of an LC medium according to any of claims 1 to 13, comprising the step of mixing a liquid-crystalline component B) as defined in claim 1 with one or more compounds of the formulae I, II and III as defined in one or more of claims 1 to 6, and optionally with further liquid-crystalline compounds and / or additives.

15. An LC display comprising an LC medium as defined in any one of claims 1 to 14.

16. The LC display as claimed in claim 15, which is a PS-VA display or a polymer-stabilized SA-VA display.

17. LC display according to claim 15 or 16, characterized in that It comprises two substrates, at least one of which is transparent to light, electrodes provided on each substrate or two electrodes provided on only one of the substrates, and a layer of an LC medium as defined in any one of claims 1 to 15 located between the substrates, wherein the polymerisable compound between the substrates of the display is polymerised.

18. Process for producing an LC display according to any one of claims 15 to 17, comprising the following steps: An LC medium as defined in any one of claims 1 to 14 is provided between substrates of a display, and the polymerisable compound is polymerised.

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