CN111676026A - Method for producing liquid crystal displays comprising a liquid-crystalline medium with a polymerizable compound - Google Patents

Abstract

The invention relates to a method for producing Liquid Crystal (LC) displays comprising an LC medium comprising one or more polymerisable compounds, in particular LC displays for the polymer sustained alignment (PS, PSA) or self-alignment (SA) type. The method comprises two or more polymerisation steps, one applying a potential to the electrodes of the display and one not applying a potential to the electrodes of the display.

Description

Method for producing liquid crystal displays comprising a liquid-crystalline medium with a polymerizable compound

Technical Field

The invention relates to a method for producing Liquid Crystal (LC) displays comprising an LC medium comprising one or more polymerisable compounds, in particular LC displays for the polymer sustained alignment (PS, PSA) or self-alignment (SA) type. The method comprises two or more polymerization steps, wherein an electrical potential is applied and not applied to the electrodes of the display.

Background

One of Liquid Crystal Display (LCD) modes currently used is a TN (twisted nematic) mode. However, the TN LCD has a disadvantage of strong viewing angle dependence of contrast.

In addition, so-called VA (vertical alignment) displays having a wider viewing angle are known. The LC cell of a VA display contains a layer of an LC medium between two transparent electrodes, wherein the LC medium usually has a negative dielectric anisotropy. In the off-state, the molecules of the LC layer are aligned planar (homeotropic) perpendicular to the electrode surfaces or have a tilted homeotropic alignment. When a voltage is applied to the two electrodes, a realignment of the LC molecules parallel to the electrode surfaces occurs.

In addition, OCB ("optically compensated bend") displays are known, which are based on birefringent effects and have an LC layer (which has a so-called "bend" alignment and generally a positive dielectric anisotropy). Upon application of a voltage, a realignment of the LC molecules perpendicular to the electrode surface occurs. In addition, OCB displays typically contain one or more birefringent optical retardation films to prevent undesirable light transmission of the bent cell in the dark state. OCB displays have a wider viewing angle and a shorter response time than TN displays.

Also known are so-called IPS ("in-plane switching") displays, which contain an LC layer between two substrates, wherein 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 is thereby generated between them with a significant component parallel to the LC layer. This results in realignment of the LC molecules in the plane of the layer.

In addition, so-called FFS (fringe field switching) displays have been reported (see in particular s.h. jung et al, jpn.j.appl.phys., vol 43, No. 3,2004,1028) which contain two electrodes on the same substrate, one of which is structured in a comb-like manner and the other is unstructured. This produces a strong so-called "fringe field", i.e. close to the strong electric field at the edges of the electrodes, and an electric field in the entire cell which has both a strong vertical component and a strong horizontal component. FFS displays have a small viewing angle dependence of the contrast. FFS displays usually contain an LC medium with a positive dielectric anisotropy and an alignment layer, usually of polyimide, which provides a planar alignment of the molecules of the LC medium.

FFS displays may operate as active matrix or passive matrix displays. In the case of active matrix displays, individual pixels are typically addressed by integrated non-linear active elements such as transistors (e.g. thin film transistors or "TFTs"), whereas in the case of passive matrix displays, individual pixels are typically addressed according to a multiplexing method as known in the art.

Furthermore, FFS displays have been disclosed (see s.h.lee et al, appl.phys.lett.73(20),1998, 2882-. LC media with negative dielectric anisotropy exhibit a more favorable director orientation with less tilt and more twisted orientation than LC media with positive dielectric anisotropy, as a result of which these displays have a higher transmission. The display further comprises an alignment layer, preferably polyimide provided on at least one of the substrates, which is in contact with the LC medium and induces planar alignment of the LC molecules of the LC medium. These displays are also referred to as "super luminance FFS (UB-FFS)" mode displays. These displays require LC media with high reliability.

The term "reliability" as used hereinafter means the quality of the performance of the display during time and under different stress loads (such as light loads), temperature, humidity, voltage, and includes display effects such as image sticking (surface and line image sticking), non-uniformity (mura), stains (yogore), etc., as known to those skilled in the art of LC displays. As a standard parameter for classifying reliability, a Voltage Holding Ratio (VHR) value, which is a measure for maintaining a constant voltage in a test display, is generally used. Among other factors, high VHR is a prerequisite for high reliability of LC media

In the newer type of VA displays, the uniform alignment of the LC molecules is limited to a plurality of relatively small domains within the LC cell. Disclination (also known as tilt domains) may exist between these domains. The VA display with the tilt domain has larger contrast ratio and viewing angle independence of gray scale compared with the conventional VA display. In addition, this type of display is easier to produce, since no additional electrode surface treatment (e.g. by rubbing) for uniformly aligning the molecules in the on-state is required anymore. Alternatively, the preferential direction of the tilt angle or pre-tilt angle is controlled by the special design of the electrodes.

In so-called MVA (multi-domain vertical alignment) displays, this is usually achieved by electrodes having protrusions (protrusion) which cause a local pretilt. Thereby, the LC molecules are aligned parallel to the electrode surfaces in different directions within different, defined cell regions upon application of a voltage. This allows a "controlled" switching and prevents the formation of disturbing misdirected lines. While this arrangement improves the viewing angle of the display, it results in a reduction in its light transmission. A further improvement of MVA uses protrusions on only one electrode side, while the opposite electrode has slits (slit), which improves the light transmission. The slit electrodes generate a non-uniform electric field in the LC cell when a voltage is applied, meaning that controlled switching is still achieved. To further improve the light transmission, the interval between the slit and the projection may be enlarged, but this in turn leads to an increase in the response time. In so-called PVA ("patterned VA") displays, the protrusions are made completely redundant, since the two electrodes are structured on opposite sides by slits, which results in increased contrast and improved light transmission, but which 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 desirable to shorten the response time of the display and to improve the contrast and brightness (transmittance) of the display.

Another development is the so-called PS ("polymer stabilized") or PSA ("polymer sustained alignment") type display, for which the term "polymer stabilized" is occasionally also used. In these, a small amount (e.g. 0.3 wt%, typically <1 wt%) of one or more polymerisable compounds, preferably polymerisable monomer compounds, is added to the LC medium and after charging the LC medium into the display, it is polymerised or crosslinked in situ (typically by UV-photopolymerisation) while optionally applying a voltage to the electrodes of the display. The polymerization is carried out at a temperature at which the LC medium exhibits a liquid-crystalline phase, generally at room temperature. The addition of polymerisable mesogenic or liquid-crystalline compounds (also known as reactive mesogens or "RMs") to the LC mixture has proven particularly suitable.

The term "PSA" is used hereinafter when referring to displays of the general polymer sustained alignment type, and "PS" when referring to a particular display mode (e.g. PS-VA, PS-TN, etc.), unless otherwise indicated.

Furthermore, the term "RM" is used hereinafter when referring to polymerisable mesogenic or liquid crystalline compounds, unless otherwise indicated.

Meanwhile, the ps (a) principle is being used for various conventional LC display modes. Thus, for example, PS-VA, PS-OCB, PS-IPS, PS-FFS, PS-UB-FFS and PS-TN displays are known. Polymerization of the RM, in the case of PS-VA and PS-OCB displays, preferably takes place with an applied voltage, and in the case of PS-IPS displays with or without, preferably without, an applied voltage. As can be verified in the test cell, the ps (a) method results in a pre-tilt in the cell. In the case of PS-OCB displays, for example, the bend structure can be stabilized so that the offset voltage is not required 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 may be used. In addition, however, it is also possible to handle (manage), for example, with only one structured electrode side without protrusions, which considerably simplifies the production and at the same time yields very good contrast and very good light transmission.

Furthermore, so-called positive-VA displays ("positive VA") have proven to be a particularly advantageous mode. Similar to conventional VA displays, in positive-VA displays the initial orientation of the LC molecules in the initial state when no voltage is applied is homeotropic, i.e. substantially perpendicular to the substrates. However, in contrast to conventional VA displays, LC media with positive dielectric anisotropy are used in positive-VA displays. Similarly to in commonly used IPS displays, the two electrodes in positive VA displays are arranged on only one of the two substrates and preferably exhibit an intermeshing and comb-like (interdigitated) structure. The LC molecules are turned into an orientation substantially parallel to the substrate by applying a voltage to the interdigitated electrodes that creates an electric field substantially parallel to the LC medium layer. Polymer stabilization (by adding RMs (which are polymerized in the display) to the liquid-crystalline medium) has also proven to be advantageous in positive VA displays, as a result of which a significant reduction in the response time can be achieved.

PS-VA displays are described, for example, in EP 1170626 a2, US 6,861,107, US 7,169,449, US2004/0191428 a1, US 2006/0066793a1 and US 2006/0103804 a 1. PS-OCB displays are described, for example, in T.J-Chen et al, Jpn.J.appl.Phys.45,2006,2702-2704 and S.H.Kim, L.C-Chien, Jpn.J.appl.Phys.43,2004, 7643-7647. PS-IPS displays are described, for example, in US 6,177,972 and appl.phys.lett.1999,75(21), 3264. PS-TN displays are described, for example, in Optics Express 2004,12(7), 1221.

Under the layer formed by the phase separation and polymerization RM inducing the pre-tilt angle described above, the PSA display typically contains an alignment layer, e.g. of polyimide, which provides an initial alignment of the LC molecules prior to the polymer stabilization step.

Rubbed polyimide layers have long been used as alignment layers. The rubbing method causes various problems such as unevenness, contamination, electrostatic discharge problems, residue, and the like. In general, the effort and cost of producing such polyimide layers is relatively high. Therefore, instead of rubbing the polyimide layer, it is proposed to use a polyimide layer prepared by photo-alignment using a photo-inducible alignment sequence of alignment surfaces. This can be achieved by means of polarized light, via photolysis, photodimerization or photoisomerization.

In addition, it has been observed that adverse interactions of the polyimide alignment layer with certain compounds of the LC medium often result in a reduction of the electrical resistance of the display. The number of suitable and useful LC compounds is thus significantly reduced at the expense of display parameters such as viewing angle dependence, contrast and response time which are intended to be improved by the use of such LC compounds. It is therefore desirable to omit the polyimide alignment layer.

For some display modes, this is achieved by adding a self-aligning agent or additive to the LC medium which induces the desired alignment in situ by a self-assembly mechanism, such as homeotropic or planar alignment. Thus, alignment layers on one or both of the substrates may be omitted. These display modes are also referred to as "self-aligned", "self-aligned" or "self-aligned" (SA) modes.

In SA 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, compounds having an organic core group and one or more polar anchor groups attached thereto, which can interact with the substrate surface such that the additives on the substrate surface align and also induce the desired alignment in the LC molecules. Preferred self-aligning additives comprise, for example, mesogenic groups and linear or branched alkyl side chains terminated by one or more polar anchoring groups, for example selected from hydroxyl, carboxyl, amino or thiol groups. The self-aligning additive may also contain one or more polymerizable groups that can be polymerized under similar conditions as the RM used in the PSA process.

SA-VA displays have been disclosed hitherto. Suitable self-aligning additives that induce homeotropic alignment, especially for use in VA-mode displays, are disclosed in, for example, US 2013/0182202 a1, US 2014/0138581 a1, US 2015/0166890 a1, US2015/0252265 a1, and US 2018/0142152 a 1.

The SA mode may also be used in combination with the PSA mode. The LC media used in this combined mode display therefore contains both one or more RMs and one or more self-aligning additives.

Hereinafter, the display combining the SA and PSA modes is also simply referred to as "PS-SA" display. In addition, unless otherwise indicated, the term "PSA mode" or "PSA display" as used hereinafter should be understood to include SA and PS-SA modes and displays.

LC displays, including PSA and SA mode displays, may operate as active matrix or passive matrix displays. In the case of active matrix displays, individual pixels are typically addressed by integrated non-linear active elements such as transistors (e.g. thin film transistors "TFTs"), whereas in the case of passive matrix displays, addressing is typically done by multiplexing methods as known in the art.

If the display is not one of the SA modes, it also contains alignment layers on one or both of the substrates forming the display cell. The alignment layer is typically applied to the electrode (where such an electrode is present) such that it is in contact with the LC medium and induces an initial alignment of the LC molecules. The alignment layer also comprises or consists of, for example, polyimide, which again may be rubbed or may be prepared by a photo-alignment process. Sometimes, the SA mode and the single-sided alignment layer are combined.

Especially for monitor and especially TV applications, there is a constant demand for optimization of the response time and contrast and brightness (and thus also transmittance) of liquid crystal displays. PSA processes can provide key advantages herein. In particular in the case of PS-VA, PS-IPS, or PS-FFS, a reduction in response time associated with a measurable pretilt in the test cell can be achieved without significant deleterious effects on other parameters.

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

However, the problem arises that not all combinations of LC mixtures and one or more RMs are suitable for PSA displays, since, for example, an insufficient tilt or no tilt at all is established, or since, for example, VHR is not sufficient for TFT display applications. It has furthermore been found that LC mixtures and RMs known from the prior art still have some disadvantages when used in PSA displays. Therefore, not every known RM soluble in LC mixtures is suitable for PSA displays. Furthermore, it is often difficult to find a suitable selection criterion for the RM, in addition to directly measuring the pretilt in the PSA display. The selection of a suitable RM becomes even smaller if it is desired to carry out the polymerization by means of UV light without the addition of a photoinitiator, which may be advantageous for certain applications.

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

Typically, UV photopolymerization in PSA display production processes is carried out in two steps. In a first step, hereinafter also referred to as the "UV 1 step", the LC medium is exposed to UV radiation emitted by a radiation source (hereinafter also referred to as "light source") while a voltage is applied to the electrode structure to create a pre-tilt angle. In a second step, hereinafter also referred to as "UV 2 step", the LC medium is exposed to UV radiation, without voltage, to ensure complete polymerization (final curing) of any residual RM molecules that were not polymerized in the UV1 step. As described above, complete polymerization is important because residual unreacted RM molecules may cause undesirable effects such as reduced reliability in the display, reduced tilt angle stability, or image sticking.

The conventional UV photopolymerization method including the UV1 step and the UV2 step is hereinafter also simply referred to as "PSA method".

Another problem in producing PSA displays is the presence or removal of residual amounts of unpolymerized RM, especially after the polymerization step used to create the pretilt angle in the display. For example, such unreacted RMs may detrimentally affect the properties of the display by, for example, polymerizing in an uncontrolled manner during operation after the display is manufactured.

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

This "image sticking" may occur on the one hand if LC host mixtures with low VHR are used. The daylight or UV-components of the backlight may initiate decomposition reactions in which the LC molecules are undesirable and thereby initiate the production of ionic or free radical impurities. These can accumulate, particularly at the electrodes or alignment layers, where they can reduce the effective applied voltage. This effect can also be observed in conventional LC displays without a polymer component.

Furthermore, an additional "image sticking" effect due to the presence of unpolymerized RMs is often observed in PSA displays. The uncontrolled polymerization of the residual RMs is initiated here by UV light from the environment or from a backlight. This changes the tilt angle after a number of addressing periods in the switched display area. As a result, a change in transmittance may occur in the switched region, while it remains unchanged in the unswitched region.

It is therefore desirable that polymerization of RMs during the production of PSA displays proceeds as completely as possible and that the presence of unpolymerized RMs in the display is excluded or reduced to a minimum as possible. Thus, there is a need for RM and LC mixtures that are capable of or support highly efficient and complete polymerization of RMs. Furthermore, a controlled reaction of the residual RM amount is desired. It would be simpler if the RMs polymerized faster and more efficiently than the materials known hitherto.

Another problem observed in the operation of PSA displays is the stability of the pretilt angle. Thus, it was observed that the pretilt angle (which is generated during the manufacturing process of the display by polymerizing the RM as described above) does not remain constant, but deteriorates after the display is subjected to voltage stress during its operation. This can negatively impact display performance, for example by increasing black state transmission and thus reducing contrast.

Another problem observed in the prior art is that the use of conventional LC media in LC displays, including but not limited to SA and PSA type displays, often leads to non-uniformities in the display, especially when the LC media is filled in display cells manufactured using the One Drop Filling (ODF) method. This phenomenon is also referred to as "ODF non-uniformity". It is therefore desirable to provide an LC medium that results in reduced ODF non-uniformity.

In particular, if the display mode is a VA type mode, such as MVA, PVA or PS-VA, the imprinting of the droplets is often visible after fabrication because the droplets are not uniformly dispersed throughout the display area. In conventional VA modes, such as MVA or PVA for example, the inhomogeneity substantially disappears over time. However, in PSA displays, the non-uniformity is maintained and the droplet imprint is "fixed" by the polymerization process.

In the prior art, attempts have been made to minimize ODF drip non-uniformity, for example by optimizing process conditions, panel design and/or LC materials such as LC host mixtures or RMs, for example by reducing RM concentration. However, even after reducing the tact time of the polymerization process by increasing the intensity of the short-wave part of the irradiation spectrum, a burst of ODF inhomogeneity was observed. Furthermore, the reduction of RM concentration may negatively affect the generation of the pre-tilt angle.

Accordingly, there remains a need for improved ways or methods of reducing ODF non-uniformities in PSA displays.

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

There is thus still a great need for LC displays, in particular those of the SA and PSA modes, and LC media and polymerisable compounds for use in such displays, which do not exhibit the disadvantages described above or exhibit them only to a small extent and have improved properties.

In particular, there is a great need for SA and/or PSA displays and LC media and polymerizable compounds for such displays, which enable high specific resistance at the same time in a large operating temperature range, short response times even at low temperatures and low threshold voltages, low tilt angles, a large number of grey scales, high contrast and wide viewing angles, good reflectivity and high contrast also in daylight. Furthermore, the compounds and the LC media should show a high reliability and high values of VHR after UV exposure and, in the case of polymerizable compounds, a low melting point and a high solubility in the LC host mixture. In displays for mobile applications, it is particularly desirable to have available LC media that exhibit low threshold voltages and high birefringence.

In the prior art, several types of RMs have been reported for use in SA and PSA displays, for example RMs having a core of biphenyl or terphenyl mesogens and two or three polymerizable acrylate or methacrylate groups attached thereto. Biphenyl RMs are shown to exhibit limited polymerization speed but good reliability parameters, such as high VHR or tilt stability, while terphenyl RMs are shown to exhibit fast polymerization speed but limited reliability parameters. It is therefore desirable to have available RMs that exhibit both fast polymerization speed and good reliability parameters.

The invention is based on the following objectives: LC displays, in particular SA and PSA displays, based on suitable LC media and RMs, which do not have the disadvantages indicated above or to a lesser extent.

In particular, the invention is based on the object of providing LC displays of the SA and PSA display type which achieve very high specific resistance values, high VHR values, high reliability, low threshold voltages, short response times, high birefringence, high contrast, in particular show good UV absorption at longer wavelengths, enable a rapid and complete polymerization of the RM, enable a low tilt angle to be generated, preferably as rapidly as possible, enable a high stability of the pretilt even after longer times and/or after UV exposure, reduce or prevent the occurrence of "image sticking" and "ODF inhomogeneities" in the display, and show high solubility in the LC medium typically used as a host mixture in PSA displays, with as rapid and complete polymerization of the RM as possible.

These objects have been achieved according to the present invention by methods and materials as described in the present application. In particular, it has been surprisingly found that a method for producing an LC display as described hereinafter allows the advantageous effects as mentioned above to be achieved.

It was surprisingly found that the production process of PSA displays facilitates a fast and complete UV photopolymerization even without the addition of photoinitiators, which leads to a fast generation of small and stable tilt angles; reduction of image sticking and ODF non-uniformities in displays, resulting in high reliability and high VHR values after UV photo-polymerisation, especially in the case of LC host mixtures containing LC compounds with alkenyl groups; and enables fast response times, low threshold voltages and high birefringence.

It has also surprisingly been found that in SA-PSA displays, the method of manufacturing LC displays disclosed and claimed below allows a more precise control of the generation of tilt angles and facilitates the use of LC mixtures that typically generate very large pre-tilt angles (small tilt angles) rapidly.

Disclosure of Invention

A first aspect of the invention relates to a method of manufacturing an LC display,

wherein the LC display comprises a pair of substrates provided with electrodes on one or both substrates, and a layer of LC medium between the substrates,

and the LC medium comprises

A polymerizable component A) consisting of one or more polymerizable compounds,

liquid-crystal component B), hereinafter also referred to as "LC-host-mixture", which comprises and preferably consists of one or more mesogenic or liquid-crystalline compounds,

wherein the method comprises the following steps:

an LC medium is provided between the substrates of the LC display,

in a first UV method step (UV1-a), the polymerisable component A) of the LC medium is polymerised without applying an electrical potential to the electrodes,

wherein the alignment state of the LC medium is preferably unchanged,

then the

In a second UV method step (UV1-b), the polymerisable component a) of the LC medium is polymerised in the presence of an electric potential or field applied to the electrodes.

In a second UV method step, the LC medium preferably adopts a pre-tilt in a direction coinciding with its tilt direction under the influence of the potential applied to the electrodes during the switching operation of the LC display. However, the details and results of the tilting are completely different from the conventional PSA process due to the previous first UV step.

The liquid-crystalline component B) of the LC medium is also referred to below as "LC host mixture" and preferably comprises one or more, preferably at least two, mesogenic or LC compounds selected from compounds which are not polymerizable and are not products of polymerization.

PSA displays have two electrodes, preferably in the form of transparent layers, which are applied to one or both of the substrates. In some displays, for example in PS-VA, PS-OCB, PS-TN or polymer stabilized SA-VA displays, one electrode is applied to each of the two substrates. In other displays, for example in PS-positive-VA, PS-IPS or PS-FFS, PS-UB-FFS or polymer stabilized SA-FFS displays, both electrodes are applied to only one of the two substrates.

Detailed Description

The production process of LC displays according to the invention shows the following advantageous properties when used in PSA and PS-SA displays:

a stable tilted homeotropic orientation of the LC medium with respect to the substrates surrounding the medium,

a relatively low level of ODF non-uniformity,

-a suitable tilt generation within a certain method window,

rapid polymerization after UV treatment, resulting in minimal residual RM,

high voltage holding ratio after UV treatment,

good tilt stability and sufficient stability against heat, and

tolerance to variable amounts of polymerizable additives, especially higher contents of these additives.

The first and second UV process steps are preferably carried out in such a way that the LC medium is not completely polymerized after the first step. In a preferred method, the first UV method step is ended and preferably immediately replaced by the second UV method step before the first UV method step completely polymerizes the LC medium. Preferably, the first method step and the second method step independently have a duration of 10 to 200s, more preferably 20 to 150 s. At the first and secondIn the method step, the intensity of the UV light is preferably independently selected from 0.1 to 5mW/cm²The metal halide lamp (incident UV, measured at about 313 nm) or equivalent.

Preferably, the first and second UV method steps of the LC medium are followed by a third polymerization step, which is again carried out without applying a potential on the electrodes and without an electric field. This third step is similar to the conventional second UV step (UV2 step) for final curing. In this third process step, any residual polymerizable monomer is reduced as little as possible by further irradiation. Preferably, this step is extended until some low value of residual RM is reached. This may take from 2 minutes to 5 hours, typically over an hour. The light source is preferably a UV-C fluorescent lamp.

The polymerisable component a) of the LC medium comprises one or more polymerisable monomers, preferably selected from mono-and di-methacrylates. The amount of polymerizable component a) is preferably from 0.1 to 5% by weight, more preferably from 0.2 to 3% by weight.

Preferably, the LC medium comprises one or more polymerisable compounds selected from formula I:

P-Sp-A¹-(Z¹-A²)_z-R^bI

wherein the individual radicals, independently of one another and identically or differently at each occurrence, have the following meanings.

R^bIs P-Sp-or R, preferably P-Sp-,

r is F, Cl, -CN, or a linear, branched or cyclic alkyl group having 1 to 25C atoms, wherein one or more non-adjacent CH groups₂-the radicals are optionally replaced by-O-, -S-, -CO-O-, -O-CO-O-in such a way that O-and/or S-atoms are not directly linked to one another, and wherein one or more H atoms are each optionally replaced by F or Cl,

p is a polymerizable group, and P is a polymerizable group,

sp is a spacer group optionally substituted with P, or a single bond,

A¹、A²is a monocyclic or polycyclic aromatic or heteroaromatic group having 4 to 20 ring atoms, which is optionally substituted by one or more groups L or P-Sp-,

Z¹is-O-, -S-, -CO-O-, -O-CO-O-, -OCH₂-、-CH₂O-、-SCH₂-、-CH₂S-、-CF₂O-、-OCF₂-、-CF₂S-、-SCF₂-、-(CH₂)_n1-、-CF₂CH₂-、-CH₂CF₂-、-(CF₂)_n1-、-CH＝CH-、-CF＝CF-、-CH＝CF-、-CF＝CH-、-C≡C-、-CH＝CH-CO-O-、-O-CO-CH＝CH-、-CH₂-CH₂-CO-O-、-O-CO-CH₂-CH₂-、-CR⁰R⁰⁰-, or a single bond,

R⁰,R⁰⁰is H or alkyl having 1 to 12C atoms,

l is F, Cl, -CN, P-Sp-, or a linear, branched or cyclic alkyl or alkenyl group having 1 to 25C atoms, wherein one or more non-adjacent CH₂-the group is optionally replaced by-O-, -S-, -CO-O-, -O-CO-O-in such a way that O-atoms and/or S-atoms are not directly attached to each other, and wherein one or more H atoms are each optionally replaced by P-Sp-, F or Cl,

z is 0,1,2 or 3,

and

n1 is 1,2,3 or 4.

The amount of polymerizable compound of formula I is preferably 0.2 to 0.8% by weight, more preferably 0.25 to 0.5%.

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

In both photopolymerization steps of the PSA process, the UV lamp and RM should be chosen such that the RM has a maximum absorption in the wavelength range of the UV lamp emission spectrum to ensure efficient and complete polymerization.

For example, typical RMs used in the prior art for the production of PSA displays are biphenyl diacrylate or biphenyl dimethacrylate, which may also be fluorinated. Biphenyl dimethacrylate has an absorption spectrum with strong absorption at the short end of the UV spectrum, especially at wavelengths below 300 nm. Thus, the UV lamp should be selected such that its emission spectrum shows sufficient overlap with the absorption spectrum of the RM to achieve sufficient polymerization in the PSA process.

Currently used PSA methods have several drawbacks that can negatively impact display performance and operation.

The LC medium preferably comprises a self-aligning additive for homeotropic alignment (further also referred to as SA additive), which may be polymerizable or non-polymerizable. The SA additive is here mostly a polymerisable species and will be considered as part of the polymerisable component a) of the LC medium. The amount of SA additive is preferably from 0.1 to 2.5 wt%, more preferably from 0.2 to 2%, most preferably from 0.3% or more to 1.5% or less.

SA additives are known in the art. Suitable self-aligning additives for homeotropic alignment, in particular for VA-mode displays, are disclosed, for example, in US 2013/0182202 a1, US2015/0252265 a1 and US 2018/0142152 a 1.

Preferably, the SA additive is selected from one or more compounds of formula II:

MES-R²

MES is a rod-like mesogenic group comprising two or more rings which are directly or indirectly connected to each other or which are fused to each other, which are optionally substituted and whose mesogenic group is optionally additionally substituted by one or more polymerizable groups which are connected to MES directly or via a spacer, and

R^ais a polar anchor group, located in a terminal position of the rod-like mesogenic group MES, comprising at least one carbon atom and at least one group selected from: -OH, -SH, -COOH, -CHO, a primary or secondary amine function or a group having three or more O atoms,

preferably a group having one or two OH groups, and which optionally contains one or two polymerizable groups P.

As used herein, the term rod-like refers to an elongated cylindrical or rod-like shape of a molecule or its central ring group (which constitutes a so-called mesogenic group). Rod-like mesogens are one prerequisite for the desired liquid crystalline nematic phase which is preferably used herein.

As used herein, the terms "active layer" and "switchable layer" mean a layer comprising one or more molecules having structural and optical anisotropy (e.g., LC molecules) that 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 in an electro-optic display, such as an LC display.

As used herein, the terms "tilt" and "tilt angle" are understood to mean the tilted alignment of LC molecules of an LC medium with respect to the cell surface in an LC display, here preferably a PSA display. The tilt angle here means an average angle (<90 °) between the longitudinal molecular axis of the LC molecules (LC director) and the plane-parallel outer plates forming the LC cell. Here a low value of the tilt angle (i.e. a large deviation from a 90 angle) corresponds to a large pretilt. Suitable methods for measuring the tilt angle are given in the examples. Unless otherwise stated, the values of the tilt angle disclosed in the context are relevant to this measurement method.

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

The term "polymerizable compound" as used herein is understood to mean a polymerizable monomer compound, unless otherwise specified.

The SA-VA or SA-FFS displays produced according to the invention will have a polymer stable mode, since they contain or are manufactured by using LC media comprising RMs of formula I. Thus, as used herein, the terms "SA-VA display" and "SA-FFS display" when referring to displays produced according to the present invention should be understood to refer to polymer stabilized SA-VA or SA-FFS displays, even if not explicitly mentioned.

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", oligomer or "polymer".

As used herein, the term "non-polymerizable compound" is understood to mean a compound that does not contain functional groups suitable for polymerization under the conditions typically applied to RM polymerization.

As used herein, the term "mesogenic group" is known to those skilled in the art and described in the literature, and it denotes a group that contributes substantially to the creation of a Liquid Crystal (LC) phase in low molecular weight or polymeric materials due to its anisotropic nature of attractive and repulsive interactions. The compound comprising mesogenic groups (mesogenic compound) does not necessarily have an LC phase per se. Mesogenic compounds may also exhibit LC phase behavior only after mixing with other compounds and/or after polymerization. Typical mesogenic groups are for example rigid rod-like or disk-like units. Terms and definitions used in relation to mesogenic or LC compounds are given in Pure appl.chem.2001, 73(5),888 and c.tschierske, g.pelzl, s.diele, angelw.chem.2004, 116, 6340-6368.

As used herein, the term "spacer group" (hereinafter also referred to as "Sp") is known to those skilled in the art and is described in the literature, see, e.g., Pure appl.chem.2001, 73(5),888 and c.tschierske, g.pelzl, s.diele, angelw.chem.2004, 116, 6340-6368. As used herein, the term "spacer group" or "spacer group" means a flexible group, e.g. an alkylene group, which is attached to the mesogenic group or polymerizable group(s) in the polymerizable mesogenic compound.

In the context of this and other contexts,

represents a trans-1, 4-cyclohexylidene ring, and

represents a1, 4-phenylene ring.

In the group

A single bond shown between two ring atoms may be attached to any free position of the benzene ring.

In this context "organic group" means a carbon or hydrocarbon group.

"carbon group" means a mono-or polyvalent organic group comprising at least one carbon atom, wherein the group does not comprise other atoms (e.g., -C.ident.C-) or optionally comprises 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" denotes a carbon group additionally comprising one or more H atoms and optionally one or more heteroatoms, such As N, O, S, B, P, Si, Se, As, Te or Ge.

"halogen" means F, Cl, Br or I, preferably F or Cl.

-CO-, -C (═ O) -, and-C (O) -represent a carbonyl group, i.e.

The carbon or hydrocarbyl groups may be saturated or unsaturated groups. Unsaturated groups are for example aryl, alkenyl or alkynyl groups. Carbon or hydrocarbyl groups having more than 3C atoms may be linear, branched and/or cyclic and may also contain spiro or fused rings.

The terms "alkyl", "aryl", "heteroaryl", and the like also include multivalent groups such as alkylene, arylene, heteroarylene, and the like.

The term "aryl" denotes an aromatic carbon group or a group derived therefrom. The term "heteroaryl" denotes an "aryl" group as defined above comprising one or more heteroatoms, preferably selected from N, O, S, Se, Te, Si and Ge.

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

Further preferred carbon and hydrocarbyl groups are C₁-C₂₀Alkyl radical, C₂-C₂₀Alkenyl radical, C₂-C₂₀Alkynyl, C₃-C₂₀Allyl radical, C₄-C₂₀Alkyldienyl radical, C₄-C₂₀Polyalkenyl radical, C₆-C₂₀Cycloalkyl radical, C₄-C₁₅Cycloalkenyl radical, C₆-C₃₀Aryl radical, C₆-C₃₀Alkylaryl group, C₆-C₃₀Aralkyl radical, C₆-C₃₀Alkylaryloxy radical, C₆-C₃₀Arylalkoxy group, C₂-C₃₀Heteroaryl group, C₂-C₃₀A heteroaryloxy group.

Particularly preferred is C₁-C₁₂Alkyl radical, C₂-C₁₂Alkenyl radical, C₂-C₁₂Alkynyl, C₆-C₂₅Aryl and C₂-C₂₅A heteroaryl group.

Further preferred carbyl and hydrocarbyl radicals are straight-chain, branched or cyclic alkyl radicals having 1 to 20, preferably 1 to 12C atoms, which are unsubstituted or mono-or polysubstituted by F, Cl, Br, I or CN, and where one or more non-adjacent CH's are present₂The radicals may each, independently of one another, be substituted by-C (R)^x)＝C(R^x)-、-C≡C-、-N(R^x) -, -O-, -S-, -CO-O-, -O-CO-O-are substituted in such a way that O and/or S atoms are not directly linked to one another.

R^xPreferably represents H, F, Cl, CN, a linear, branched or cyclic alkyl chain having 1 to 25C atoms, wherein furthermore one or more non-adjacent C atoms may be replaced by-O-, -S-, -CO-O-, -O-CO-O-, and wherein one or more H atoms may be replaced by F or Cl, or optionally substituted alkyl chains having 6An aryl or aryloxy group of up to 30C atoms, or an optionally substituted heteroaryl or heteroaryloxy group having 2 to 30C atoms.

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, cyclopentylmethyl, n-hexyl, cyclohexyl, 2-ethylhexyl, n-heptyl, cycloheptyl, n-octyl, cyclooctyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, trifluoromethyl, perfluoro-n-butyl, 2,2, 2-trifluoroethyl, perfluorooctyl, perfluorohexyl, and the like, and combinations thereof.

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

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

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-hexoxy, n-heptoxy, n-octoxy, n-nonoxy, n-decoxy, n-undecoxy, n-dodecoxy and the like.

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

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 comprise a combination of fused and linked rings. Heteroaryl contains one or more heteroatoms, preferably selected from O, N, S and Se.

Particularly preferred are mono-, bi-or tricyclic aryl groups having 6 to 25C atoms and mono-, bi-or tricyclic heteroaryl groups having 5 to 25 ring atoms, which optionally contain fused rings and are optionally substituted. Further preferred are 5-, 6-or 7-membered aryl and heteroaryl, wherein, in addition, one or more CH groups may be replaced by N, S or O in such a way that O atoms and/or S atoms are not directly attached to each other.

Preferred aryl radicals are, for example, phenyl, biphenyl, terphenyl, [1,1':3',1 "]-terphenyl-2' -yl, naphthyl, anthryl, binaphthyl, phenanthryl, 9, 10-dihydro-phenanthryl, pyrene, dihydropyrene,

Perylene, tetracene, pentacene, benzopyrene, fluorene, indene, indenofluorene, spirobifluorene (spirobifluorene), and the like.

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 radicals, such as indole, isoindole, indolizine, indazole, benzimidazole, benzotriazole, purine, naphthoimidazole, phenanthroimidazole, pyridoimidazole, pyrazinoimidazole, quinoxaloimidazole, benzoxazole, naphthooxazole, anthraoxazole, phenanthroioxazole, 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, benzocarbazine, phenanthridine, phenanthroline, thieno [2,3b ] thiophene, thieno [3,2b ] thiophene, Dithienothiophene, isobenzothiophene, dibenzothiophene, benzothiophene, benzothiadiazolethiophene, or combinations of these groups.

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

The (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 heterocycle contains one or more heteroatoms, preferably selected from Si, O, N, S and Se.

The (non-aromatic) alicyclic and heterocyclic groups may be monocyclic, i.e. contain only one ring (e.g. cyclohexane), or polycyclic, i.e. contain multiple rings (e.g. decahydronaphthalene or bicyclooctane). Saturated groups are particularly preferred. Preference is furthermore given to mono-, bi-or tricyclic radicals having 5 to 25 ring atoms, which optionally contain fused rings and are optionally substituted. Further preferred are 5-, 6-, 7-or 8-membered carbocyclic radicals in which, in addition, one or more C atoms may be replaced by Si and/or one or more CH groups may be replaced by N and/or one or more non-adjacent CH groups₂The groups may be replaced by-O-and/or-S-.

Preferred alicyclic and heterocyclic groups are, for example, 5-membered groups, such as cyclopentane, tetrahydrofuran, tetrahydrothiophene, pyrrolidine; 6-membered groups such as cyclohexane, silacyclohexane (silane), cyclohexene, tetrahydropyran, tetrahydrothiopyran, 1, 3-dioxane, 1, 3-dithiane, piperidine; 7-membered groups, such as cycloheptane; and fused groups such as tetralin, decalin, indane, bicyclo [1.1.1] pentane-1, 3-diyl, bicyclo [2.2.2] octane-1, 4-diyl, spiro [3.3] heptane-2, 6-diyl, octahydro-4, 7-methanoindan-2, 5-diyl.

Preferred substituents are, for example, solubility-promoting groups, such as alkyl or alkoxy; electron withdrawing groups such as fluorine, nitro or nitrile; or substituents which serve to raise the glass transition temperature (Tg) of the polymer, especially bulky groups such as tertiary butyl or optionally substituted aryl groups.

Particularly preferred substituents are, for example, F, Cl, CN, NO₂、CH₃、C₂H₅、OCH₃、OC₂H₅、COCH₃、COC₂H₅、COOCH₃、COOC₂H₅、CF₃、OCF₃、OCHF₂、OC₂F₅And in addition phenyl.

Preferably, it is

Wherein L has one of the meanings indicated above.

The polymerizable group P is a group suitable for use in polymerization reactions, such as free radical or ionic chain polymerization. Particular preference is given to radicals for chain polymerization, in particular those which contain a C ═ C double bond or a-C ≡ C-triple bond, and radicals which are suitable for ring-opening polymerization, for example oxetanyl or epoxy.

Preferred groups P are selected from the group consisting of: CH (CH)₂＝CW¹-CO-O-、CH₂＝CW¹-CO-、

CH₂＝CW²-O-、CH₂＝CW²-、CW¹＝CH-CO-(O)_k3-、CW¹＝CH-CO-NH-、CH₂＝CW¹-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＝CW¹-CO-NH-、CH₂＝CH-(COO)_k1-Phe-(O)_k2-、CH₂＝CH-(CO)_k1-Phe-(O)_k2-, Phe-CH ═ CH-and W⁴W⁵W⁶Si-, in which W¹Represents H, F, Cl, CN, CF₃Phenyl or alkyl having 1 to 5C atoms, in particular H, F, Cl or CH₃，W²And W³Each independently of the other, H or an alkyl radical having 1 to 5C atoms, in particular H, methyl, ethyl or n-propyl, W⁴、W⁵And W⁶Each independently of the other represents ClOxaalkyl or oxacarbonylalkyl having 1 to 5C atoms, W⁷And W⁸Each independently of the other H, Cl or alkyl having 1 to 5C atoms, Phe 1, 4-phenylene, k₁、k₂And k₃Each independently of the other represents 0 or 1, k₃Preferably represents 1, and k₄Represents an integer of 1 to 10.

Particularly preferred groups P are selected from the group consisting of: CH (CH)₂＝CW¹-CO-O-, in particular CH₂＝CH-CO-O-、CH₂＝C(CH₃) -CO-O-and CH₂CF-CO-O-, and also CH₂＝CH-O-、(CH₂＝CH)₂CH-O-CO-、(CH₂＝CH)₂CH-O-、

Most preferably selected from acrylate and methacrylate groups.

If the spacer group Sp is different from a single bond, it is preferably of the formula Sp '-X', so that each group P-Sp-corresponds to the formula P-Sp '-X' -, in which

Sp "denotes a straight-chain or branched alkylene group having 1 to 20, preferably 1 to 12C atoms, which is optionally mono-or polysubstituted by F, Cl, Br, I or CN, and wherein, in addition, one or more non-adjacent CH groups₂The radicals are each, independently of one another, -O-, -S-, -NH-, -N (R)⁰)-、-Si(R⁰R⁰⁰)-、-CO-、-CO-O-、-O-CO-、-O-CO-O-、-S-CO-、-CO-S-、-N(R⁰⁰)-CO-O-、-O-CO-N(R⁰)-、-N(R⁰)-CO-N(R⁰⁰) -, -CH-or-C.ident.C-in such a way that O and/or S atoms are not directly attached to one another,

x' represents-O-, -S-, -CO-O-, -O-CO-O-, -CO-N (R)⁰)-、-N(R⁰)-CO-、-N(R⁰)-CO-N(R⁰⁰)-、-OCH₂-、-CH₂O-、-SCH₂-、-CH₂S-、-CF₂O-、-OCF₂-、-CF₂S-、-SCF₂-、-CF₂CH₂-、-CH₂CF₂-、-CF₂CF₂-、-CH＝N-、-N＝CH-、-N＝N-、-CH＝CR⁰-、-CY²＝CY³-, -C.ident.C-, -CH-CO-O-, -O-CO-CH-or a single bond,

R⁰and R⁰⁰Each independently of the other represents H or an alkyl radical having 1 to 20C atoms, and

Y²and Y³Each representing H, F, Cl or CN independently of the other.

X' is preferably-O-, -S-, -CO-, -COO-, -OCO-, -O-COO-, -CO-NR⁰-、-NR⁰-CO-、-NR⁰-CO-NR⁰⁰-or a single bond.

Typical spacer groups Sp and-Sp '-X' -are, for example, - (CH)₂)_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)⁰R⁰⁰-O)_p1-, where p1 is an integer from 1 to 12, q1 is an integer from 1 to 3, and R⁰And R⁰⁰Have the meaning indicated above.

Particularly preferred radicals Sp and-Sp '-X' -are- (CH)₂)_p1-、-(CH₂)_p1-O-、-(CH₂)_p1-O-CO-、-(CH₂)_p1-CO-O-、-(CH₂)_p1-O-CO-O-, wherein p1 and q1 have the meaning indicated above.

Particularly preferred radicals Sp "are in each case straight-chain ethylene, propylene, butylene, pentylene, hexylene, heptylene, octylene, nonylene, decylene, undecylene, dodecylene, octadecylene, ethyleneoxyethylene, methyleneoxybutylene, ethylenethioethylene, ethylene-N-methyliminoethylene, 1-methylalkylene, ethylene, propylene and butylenyl.

In one embodiment of the present invention, the compounds of formula I and subformulae thereof compriseWith a spacer group Sp substituted by one or more polymerizable groups P, such that the group Sp-P corresponds to Sp (P)_sAnd s is not less than 2 (branched chain polymerizable group).

Preferred compounds of formula I according to this preferred embodiment are those wherein s is 2, i.e. containing the group Sp (P)₂The compound of (1). Very preferred compounds of formula I according to this preferred embodiment contain a group selected from the following formulae:

-X-alkyl-CHPP S1

-X-alkyl-CH((CH₂)_aaP)((CH₂)_bbP) S2

-X-N((CH₂)_aaP)((CH₂)_bbP) S3

-X-alkyl-CHP-CH₂-CH₂P S4

-X-alkyl-C(CH₂P)(CH₂P)-C_aaH_2aa+1S5

-X-alkyl-CHP-CH₂P S6

-X-alkyl-CPP-C_aaH_2aa+1S7

-X-alkyl-CHPCHP-C_aaH_2aa+1S8

wherein P is as defined for formula I,

alkyl represents a single bond or a straight-chain or branched alkylene group having 1 to 12C atoms, which is unsubstituted or mono-or polysubstituted with F, Cl or CN, and in which one or more non-adjacent CH's are present₂The radicals may each, independently of one another, be-C (R) in such a way that O atoms and/or S atoms are not directly bonded to one another⁰)＝C(R⁰)-、-C≡C-、-N(R⁰) -, -O-, -S-, -CO-O-, -O-CO-O-substitution, wherein R is⁰Having the meaning as indicated above, and which,

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

x has one of the meanings indicated for X' and is preferably O, CO, SO₂O-CO-, CO-O or a single bond.

Preferred spacer groups Sp (P)₂Selected from the group consisting of formulas S1, S2, and S3.

Very preferred spacer groups Sp (P)₂Selected from the following subformulae:

-CHPP S1a

-O-CHPP S1b

-CH₂-CHPP S1c

-OCH₂-CHPP S1d

-CH(CH₂-P)(CH₂-P) S2a

-OCH(CH₂-P)(CH₂-P) S2b

-CH₂-CH(CH₂-P)(CH₂-P) S2c

-OCH₂-CH(CH₂-P)(CH₂-P) S2d

-CO-NH((CH₂)₂P)((CH₂)₂P) S3a

in the compounds of formula I 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 selected from the group consisting of acrylate and methacrylate.

More preferred are compounds of formula I and subformulae thereof as described above and below, wherein all polymerizable groups P present in the compounds have the same meaning and very preferably represent acrylates or methacrylates, most preferably methacrylates.

Also preferred are compounds of formula I and subformulae thereof as described above and below, wherein R is^bIs P-Sp-.

More preferred are compounds of formula I and sub-formulae thereof as described above and below, wherein Sp represents a single bond or- (CH)₂)_p1-、-O-(CH₂)_p1-、-O-CO-(CH₂)_p1or-CO-O- (CH)₂)_p1Wherein p1 is 2,3,4, 5 or 6, and if Sp is-O- (CH)₂)_p1-、-O-CO-(CH₂)_p1or-CO-O- (CH)₂)_p1Then the O-atom or the CO-group, respectively, is attached to the benzene ring.

More preferred are compounds of formula I and sub-formulae thereof as described above and below, wherein at least one group Sp is a single bond.

More preferred are compounds of formula I and sub-formulae thereof as described above and below, wherein at least one group Sp is different from a single bond and is preferably selected from- (CH)₂)_p1-、-O-(CH₂)_p1-、-O-CO-(CH₂)_p1or-CO-O- (CH)₂)_p1Wherein p1 is 2,3,4, 5 or 6, and if Sp is-O- (CH)₂)_p1-、-O-CO-(CH₂)_p1or-CO-O- (CH)₂)_p1Then the O-atom or the CO-group, respectively, is attached to the benzene ring.

Preferably, A in formula I¹And A²Represents benzene, naphthalene, phenanthrene, anthracene, dibenzofuran or dibenzothiophene, all of which are optionally substituted by one or more groups L or P-Sp-.

Preferably, in formula I, -A¹-(Z¹-A²)_z-represents benzene, biphenylene, P-terphenylene (1, 4-diphenylbenzene), m-terphenylene (1, 3-diphenylbenzene), naphthylene, 2-phenyl-naphthylene, phenanthrene or anthracene, dibenzofuran or dibenzothiophene, all optionally substituted by one or more groups L or P-Sp-.

More preferred are compounds of formula I and sub-formulae thereof, as described above and below, wherein-A¹-(Z-A²)_z-is selected from the following formulae

Wherein the phenyl rings are optionally further substituted by one or more groups L or P-Sp-as defined for formula I.

Preferred compounds of formula I are selected from the following subformulae

Wherein the radicals are independent of one another and, identically or differently at each occurrence, have the following meanings

P, Sp has one of the meanings given in formula I or one of the preferred meanings given above and below,

R^bhaving one of the meanings given in formula I or one of the preferred meanings given above and below, preferably-Sp-P,

L¹¹、L¹²、L¹³independently of the above, is a group L, preferably F, Cl, alkyl or alkenyl,

r1, r2, r3 are 0,1,2, 3 or 4, preferably 0,1 or 2, very preferably 0 or 1,

r4, r5 is 0,1,2 or 3, preferably 0,1 or 2, very preferably 0 or 1.

Preferred are compounds of formula I and I1-I6, wherein R is^bIs P-Sp.

Further preferred are compounds of formula I and I1-I6, wherein R is^bDifferent from P-Sp.

Very particular preference is given to compounds of the formulae I1, I2 and I5.

Suitable and preferred mesogenic monomers of formula I are selected from the following formulae:

wherein the individual radicals have the following meanings:

P¹、P²and P³Each independently of the other, represents an acrylate or methacrylate group,

Sp¹、Sp²and Sp³Each independently of the others, represents a single bond or a spacer group (having one of the meanings as described above and below for Sp), and particularly preferably represents- (CH)₂)_p1-、-(CH₂)_p1-O-、-(CH₂)_p1-CO-O-、-(CH₂)_p1-O-CO-or- (CH)₂)_p1-O-CO-O-, wherein P1 is an integer from 1 to 12, further wherein the group P¹-Sp¹-、P¹-Sp²-and P³-Sp³One or more of-may represent R^aaProvided that the group P present¹-Sp¹-、P²-Sp²-and P³-Sp³At least one of-is different from R^aa，

R^aaRepresents H, F, Cl, CN or a linear or branched alkyl group having 1 to 25C atoms, wherein in addition one or more non-adjacent CH₂The radicals may also be independently of one another substituted by C (R)⁰)＝C(R⁰⁰)-、-C≡C-、-N(R⁰) -, -O-, -S-, -CO-O-, -O-CO-O-are replaced in such a way that O and/or S atoms are not linked directly to one another, and wherein furthermore one or more H atoms may be replaced by F, Cl, CN or P¹-Sp¹-instead, particular preference is given to linear or branched, optionally mono-or polyfluoro-substituted alkyl, alkoxy, alkenyl, alkynyl, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy having 1 to 12C atoms (where alkenyl and alkynyl have at least two C atoms and the branching group has at least three C atoms),

R⁰、R⁰⁰each independently of the other and eachThe same or different at each occurrence denotes H or alkyl having 1 to 12C atoms,

R^yand R^zEach representing H, F, CH independently of each other₃Or CF₃,

X¹、X²And X³Each independently of the others represents-CO-O-, -O-CO-or a single bond,

Z¹represents-O-, -CO-, -C (R)^yR^z) -or-CF₂CF₂-,

Z²And Z³Each independently of the others represents-CO-O-, -O-CO-, -CH₂O-、-OCH₂-、-CF₂O-、-OCF₂-or- (CH)₂)_n-, where n is 2,3 or 4,

l represents, identically or differently on each occurrence, F, Cl, CN or a linear or branched, optionally mono-or polyfluoro-substituted alkyl, alkoxy, alkenyl, alkynyl, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy group having 1 to 12C atoms, preferably F,

l 'and L' each independently of the other denote H, F or Cl,

k represents a number of 0 or 1,

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.

Particular preference is given to compounds of the formulae M2, M13, M17, M22, M23, M24, M30, M31 and M32.

Further preferred are the tri-reactive compounds M15 to M30, in particular M17, M18, M19, M22, M23, M24, M25, M26, M30, M31 and M32.

In the compounds of the formulae M1 to M32, the radicals

Preference is given to

Wherein L, identically or differently on each occurrence, has one of the meanings given above or 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、OC₂F₅Or P-Sp-, very preferably F, Cl, CN, CH₃、C₂H₅、OCH₃、COCH₃、OCF₃Or P-Sp-, more preferably F, Cl, CH₃、OCH₃、COCH₃Or OCF₃In particular F or CH₃。

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

-P is selected from the group consisting of: acrylates, methacrylates and oxetanes, very preferably acrylates or methacrylates,

-P is a methacrylate,

-all the groups Sp are single bonds,

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

when different from a single bond, Sp is- (CH)₂)_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, respectively, is attached to the benzene ring,

-Sp is a single bond or represents- (CH)₂)_p2-、-(CH₂)_p2-O-、-(CH₂)_p2-CO-O-、-(CH₂)_p2-O-CO-, wherein p2 is 2,3,4, 5 or 6 and an O-atom or a CO-group, respectively, is attached to the benzene ring,

-Sp(P)₂selected from the subformulae S11-S31,

-R^brepresents P-Sp-,

-R^bdo not represent or contain a polymerizable group,

-R^bdoes not represent or contain a polymerizable group and represents a linear, branched or cyclic alkyl group having 1 to 25C atoms, wherein one or more non-adjacent CH groups₂-the group is optionally replaced by-O-, -S-, -CO-O-, -O-CO-O-in such a way that O-atoms and/or S-atoms are not directly attached to each other, and wherein one or more H atoms are each optionally replaced by F, or Cl,

-L and L^14-16Selected from F, Cl, CN, alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy, each having 1 to 6C atoms, wherein one or more H atoms may optionally be replaced by F or Cl, preferably F, Cl, CN or OCH₃Very preferably, F.

Very particularly preferred compounds of the formula I and their subformulae are selected from the following table D of the present disclosure, in particular of the formulae RM-1, RM-17, RM-19, RM-35 or RM-37.

Preferably, the LC medium used according to the present invention comprises one or more self-aligning additives of formula II as defined above.

MES-R²II

The self-aligning additive comprising polymerisable groups may be polymerised in an LC medium under conditions similar to those applied for RMs in PSA processes.

Preferably, in the self-aligning additive of formula II, the group MES comprises two or more rings selected from the aromatic, alicyclic and heterocyclic groups defined above, including their preferred meanings. The most preferred ring is 1, 4-phenylene, which may be defined by L¹²And P-Sp-substituted, or 1, 4-cyclohexylene.

In formula II, the radical MES is preferably a radical selected from the following structures, which may be substituted by any substituents L¹²And P-Sp-mono or polysubstitution:

wherein

L¹²In each case independently of one another F, Cl, Br, I, -CN, -NO₂，-NCO，-NCS，-OCN，-SCN，-C(＝O)N(R⁰)₂，-C(＝O)R⁰Optionally substituted silyl, optionally substituted aryl or cycloalkyl having 3 to 20C atoms, or straight-chain or branched alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy having up to 25C atoms, where, in addition, one or more H atoms may each be replaced by F or Cl,

p represents a polymerizable group, and

sp represents a spacer group or a single bond,

and the dotted line represents a polar anchoring group R^aThe connection point of (a).

Preferably, the self-aligning additive for homeotropic alignment is selected from the group consisting of formula IIa

R²¹-[A²²-Z²²]_m2-A²²-R^aIIa

Wherein

A²¹，A²²Each independently of the others, represents an aromatic, heteroaromatic, alicyclic or heterocyclic group, which may also contain fused rings, and which may also be interrupted by a group L¹²or-Sp-P mono-or polysubstituted,

preferably independently of one another, 1, 4-phenylene, 2, 6-naphthylene or 1, 4-cyclohexylene, which may be substituted by the radicals L¹²Or a-Sp-P substitution,

L¹²in each case independently of one another F, Cl, Br, I, -CN, -NO₂，-NCO，-NCS，-OCN，-SCN，-C(＝O)N(R⁰)₂，-C(＝O)R⁰Optionally substituted silyl having 3 to 20CAn optionally substituted aryl or cycloalkyl radical of atoms, or a linear or branched alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy radical having up to 25C atoms, where, in addition, one or more H atoms may each be replaced by F or Cl,

p represents a polymerizable group, and P represents a polymerizable group,

sp represents a spacer group or a single bond,

Z²²in each case independently of one another, represents a single bond, -O-, -S-, -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-，-(CR⁰R⁰⁰)_n1-，-CH(-Sp-P)-，-CH₂CH (-Sp-P) -, or-CH (-Sp-P) CH (-Sp-P) -,

n1 represents a number of atoms of 1,2,3 or 4,

m2 represents 1,2,3,4, 5 or 6, preferably 2,3, or 4, more preferably 3,

R⁰in each case independently of one another denote alkyl having 1 to 12C atoms,

R⁰⁰in each case independently of one another, H or alkyl having 1 to 12C atoms,

R²¹independently of one another, H, halogen, straight-chain, branched or cyclic alkyl having 1 to 25C atoms, where, in addition, one or more non-adjacent CH₂The radicals may each be replaced by-O-, -S-, -CO-O-, -O-CO-, or-O-CO-O-in such a way that the O and/or S atoms are not linked directly to one another and wherein, in addition, one or more H atoms may each be replaced by F or Cl,

or a group P-Sp-, and

R^aas defined above, preferably represents a polar anchoring group further defined by: having at least one group selected from: -OH, -NH₂，NHR²²C (O) OH and-CHO or a group having three or more O atoms, wherein

R²²Represents an alkyl group having 1 to 12C atoms.

In another preferred embodiment, the LC medium or polymer stabilized SA-VA display comprises one or more self-aligning additives selected from table E below.

Anchoring group R of self-aligning additives^aMore preferably defined as

R^aAn anchoring group of the formula

Wherein

p represents a number of 1 or 2,

q represents a number of 2 or 3,

b represents a substituted or unsubstituted ring system or a fused ring system, preferably a ring system selected from benzene, pyridine, cyclohexane, dioxane or tetrahydropyran,

R²¹independently of one another, H, halogen, straight-chain, branched or cyclic alkyl having 1 to 25C atoms, where, in addition, one or more non-adjacent CH₂The radicals may each be replaced by-O-, -S-, -CO-O-, -O-CO-, or-O-CO-O-in such a way that the O and/or S atoms are not linked directly to one another and wherein, in addition, one or more H atoms may each be replaced by F or Cl,

or a group P-Sp-, and

y, which are identical or different on each occurrence, denotes-O-, -S-, -C (O) -, -C (O) O-, -OC (O) -, -NR¹¹-or a single bond,

o represents a number of 0 or 1,

X¹represent, identically or differently on each occurrence, H, alkyl, fluoroalkyl, OH, NH₂，NHR²²，NR²² ₂，OR²²C (O) OH, or-CHO,

wherein at least one group X¹Represents a group selected from-OH, -NH₂，NHR²²Radicals of C (O) OH and-CHO,

R²²Represents an alkyl group having 1 to 12C atoms,

Sp^a，Sp^c，Sp^deach independently of the other represents a spacer group or a single bond, and

Sp^brepresents a trivalent or tetravalent group, preferably CH, N or C.

Formulas II and IIa optionally include polymerizable compounds. In the present disclosure, "a medium comprising a compound of formula II/IIa" refers to both: a medium comprising a compound of formula II/IIa, or a medium comprising a compound in its polymerized form.

In the case where one or more compounds of the formula II are substituted by one or more polymerizable groups (-Sp-P), the LC medium according to the invention preferably comprises

-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 is a compound of formula II,

liquid crystal component B), hereinafter also referred to as "LC host mixture", which comprises, preferably consists of, one or more mesogenic or liquid crystal compounds.

In the compounds of the formula IIa and sub-formulae thereof, Z²²Preferably represents a single bond, -C₂H₄-，-CF₂O-or-CH₂O-is formed. In a particularly preferred embodiment, Z²²Represents a single bond.

In the compounds of the formula IIa, the group L¹²Independently of one another in each case preferably denotes F or alkyl, preferably CH₃，C₂H₅Or C₃H₇。

Preferred compounds of the formula IIa are illustrated by the following sub-formulae II-A to II-D

Wherein R is²¹，R^a，A²²，Z²²Sp, P and L¹²Has the meaning defined above for formula IIa，

m2 is independently 1,2,3 or 4, and

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

The compounds of the formulae II-A, II-B and II-C are polymerizable and preferred, the compounds of the formula II-B being most preferred.

In the compounds of the formulae II-A to II-D, L¹²Preferably represents F or alkyl, preferably CH₃，C₂H₅Or C₃H₇。

In a preferred embodiment, r1 represents 0.

The polymerizable group P of the formulae II, IIa, II-A to II-D is preferably a methacrylate, an acrylate or another substituted acrylate, most preferably a methacrylate. The group Sp is preferably- (CH)₂)_n-, where n is 2,3 or 4.

In the formulae IIa or II-A to II-D and the subformulae thereof in the context, Z²²Preferably independently represents a single bond or-CH₂CH₂-, and very particularly a single bond.

R^aPreferred expression(s)

Wherein

p is 1,2,3,4, 5 or 6, preferably 1,2 or 3,

x is 1 or 0, preferably 1, and

R²³is H, methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, n-pentyl, or-CH₂CH₂-tert-butyl.

R^aVery preferably represents-O (CH)₂)₂-OH，-O(CH₂)₃-OH，

In formula IIa and in the subformulae of formula IIa, R²¹Preferably represents a straight-chain or branched alkyl group having 1 to 8C atoms, preferably a straight-chain alkyl group. In the compounds of the formula IIa or II-A to II-D, R¹More preferably CH₃，C₂H₅，n-C₃H₇，n-C₄H₉，n-C₅H₁₁，n-C₆H₁₃Or CH₂CH(C₂H₅)C₄H₉。R²¹Furthermore may represent an alkenyloxy radical, in particular OCH₂CH＝CH₂，OCH₂CH＝CHCH₃，OCH₂CH＝CHC₂H₅Or alkoxy, especially OC₂H₅，OC₃H₇，OC₄H₉，OC₅H₁₁And OC₆H₁₃. Particularly preferred R²¹Denotes a straight-chain alkyl residue, preferably C₅H₁₁。

In a preferred embodiment of the present invention, the LC medium comprises a polymerisable compound of formula II. Combinations of polymerizable additives of formulae I and II are preferred. It is particularly preferred that

-the LC medium comprises one or more compounds of formula I selected from the subformulae M1 to M32, preferably from subformulae M2 or M13, and one or more compounds of formula II;

-the LC medium comprises one or more compounds selected from the group of its subformulae a1 to a6, preferably from subformulae a1, of formula I, and one or more compounds of formula IIa;

the LC medium comprises one or more compounds selected from formula I, and one or more compounds selected from formulae II-a to II-D, preferably selected from II-a and II-B, more preferably selected from formula II-B.

The compounds of the formulae I and II and their subformulae and intermediates can be prepared analogously to the Methods disclosed or by Methods known and described in standard works of Organic Chemistry by those skilled in the art (for example in Houben-Weyl, Methoden der organischen Chemie [ Methods of Organic Chemistry ], Thieme-Verlag, Stuttgart).

For example, compounds of formula I and II may be conveniently synthesized by esterifying or etherifying an intermediate with the corresponding acid, acid derivative or halogenated compound containing a polymerizable group P, wherein the group Sp-P or P alone represents OH.

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

The structure of the PSA display according to the invention corresponds to the usual geometry of a PSA display, as described in the prior art cited at the outset. A geometry without protrusions is preferred, wherein furthermore, in particular, those in which the electrode on the color filter side is unstructured and only the electrode on the TFT side has slots (slots). A particularly suitable and preferred electrode structure for PS-VA displays is described, for example, in US 2006/0066793a 1.

For the method according to the invention, a display with at least one structured electrode is preferred, wherein the structured portion preferably comprises slits. More preferably, the display has one structured electrode and one continuous electrode on opposite substrate sides.

Preferred LC displays of the PSA type of the present invention comprise:

a first substrate comprising pixel electrodes defining pixel areas, the pixel electrodes 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 electrodes,

a second substrate comprising a common electrode layer (which may be arranged on the entire part of the second substrate facing the first substrate), and optionally an alignment layer,

-an LC layer arranged between the first and second substrates and comprising an LC medium comprising a polymerisable component a and a liquid crystal component B as described above and below, wherein the polymerisable component a may also be polymerised.

The first and/or second alignment layer controls the alignment direction of LC molecules of the LC layer. For example, in PS-VA displays, the alignment layer is chosen to impart homeotropic (or homeotropic) alignment (i.e., perpendicular to the surface) or tilt alignment to the LC molecules. Such alignment layers may for example comprise polyimide, which may also be rubbed, or may be prepared by a photo-alignment process.

The LC layer with the LC medium may be deposited between the substrates of the display by methods conventionally used by display manufacturers, such as the so-called drop-fill (ODF) method. The polymerisable components of the LC medium are then polymerised, for example by UV photopolymerisation. According to the invention, the polymerization is carried out in at least two steps, preferably in three steps.

PSA displays may include other elements such as color filters, black matrices, passivation layers, optical retardation layers, transistor elements for individual pixel addressing, etc., all of which are well known to those skilled in the art and may be used without inventive skill.

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

After polymerization, the polymerizable compounds form crosslinked polymers, which lead to a certain pretilt 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 crosslinked polymer formed by the polymerizable compound phase separates or precipitates out of the LC medium and forms a polymer layer on the substrate or electrode, or an alignment layer provided thereon. Microscopic measurement data (e.g., SEM and AFM) have confirmed that at least a portion of the formed polymer accumulates at the LC/substrate interface.

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

Optionally one or more polymerization initiators are added to the LC medium. Suitable conditions for the polymerization and suitable types and amounts of initiators are known to the person skilled in the art and are described in the literature. Suitable for free-radical polymerization are, for example, the commercially available photoinitiators

Or

(Ciba AG). If a polymerization initiator is used, the proportion thereof is preferably from 0.001 to 5% by weight, particularly preferably from 0.001 to 1% by weight.

The polymerisable compounds are also suitable for initiator-free polymerisation, which is accompanied by considerable advantages, such as low material costs and in particular less contamination of the LC medium by possible residual amounts of initiator or degradation products thereof. The polymerization can therefore also be carried out without addition of initiator. In a preferred embodiment, the LC medium therefore does not contain a polymerization initiator.

The LC medium may also contain one or more stabilizers in order to prevent unwanted spontaneous polymerization of the RM, for example during storage or transport. Suitable types and amounts of stabilizers are known to the person skilled in the art and are described in the literature. Particularly suitable are, for example, those commercially available from

stabilizers for series (Ciba AG), e.g.

1076. If stabilizers are used, their proportion is preferably based on the total amount of RM or polymerizable component (component A)10 to 50,000ppm, particularly preferably 50 to 5,000 ppm.

In another embodiment, the liquid-crystalline medium comprises one or more chiral dopants, preferably in a concentration of from 0.01 to 1% by weight, very preferably from 0.05 to 0.5% by weight. The chiral dopants are preferably selected from the compounds of Table B below, very preferably from R-or S-1011, R-or S-2011, R-or S-3011, R-or S-4011 and R-or S-5011.

In another preferred embodiment, the liquid-crystalline medium comprises a racemate of one or more chiral dopants, preferably selected from the chiral dopants mentioned in the preceding paragraph.

In another preferred embodiment of the present invention, the liquid-crystalline medium comprises one or more further stabilizers, which are preferably selected from the following formulae:

wherein the radicals, independently of one another and identically or differently at each occurrence, have the following meanings

R^a-dIs a straight-chain or branched alkyl group having 1 to 10, preferably 1 to 6, very preferably 1 to 4C atoms, most preferably methyl,

X^Sis H, CH₃OH or O^●,

A^SIs an optionally substituted linear, branched or cyclic alkylene group having 1 to 20C atoms,

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

Preferred stabilizers of formula S3 are selected from the group consisting of formula S3A

Wherein n2 is an integer from 1 to 12, and wherein (CH)₂)_n2One or more H atoms in the radical being optionally substitutedMethyl, ethyl, propyl, butyl, pentyl or hexyl.

Very preferred stabilizers are selected from the following formulae:

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

In a preferred embodiment, the liquid-crystalline medium comprises one or more stabilizers selected from table D.

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

In another preferred embodiment, the LC media used in the present invention comprise one or more SA additives selected from formula II or a subformula thereof. The concentration of the SA additive in the LC medium is preferably 0.1 to 5%, very preferably 0.2 to 3%, most preferably 0.2 to 1.5%.

In a preferred embodiment, the LC medium or display according to the invention comprises one or more SA additives selected from table F below.

In another preferred embodiment, the SA-VA or SA-FFS displays produced according to the invention do not comprise a polyimide alignment layer.

The polymerizable compounds of the formulae I and/or II do in particular exhibit good UV absorption and are therefore particularly suitable for use in a method for producing PSA displays comprising one or more of the following features:

in displays the polymerizable medium is exposed to UV light generated by an energy-saving UV lamp (also called "green UV lamp"). These lamps are characterized by a relatively low intensity in their absorption spectra at 300-380nm (1/100-1/10 of conventional UV1 lamps) and are preferably used in the UV2 step, but optionally also in the UV1-a or UV1-b step, when avoiding high intensities is necessary for the process.

Exposure of the polymerizable medium to UV light generated by a UV lamp in the display, with a radiation spectrum shifted to longer wavelengths, preferably 340nm or longer, to avoid short UV light exposure in the PS-VA process.

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

Preferred embodiments of the present invention relate to a method of making a PSA display as described above and below, comprising one or more of the following features:

exposure of the polymerisable LC medium to a UV lamp with a power of 0.5mW/cm²To 10mW/cm²Preferably in the wavelength range of 300-380nm, which is used in the third method step (UV2 step) and optionally also in the first and second method steps (UV1-a/b step),

-exposure of the polymerizable LC medium to UV light having a wavelength of 340nm or more, and preferably 400nm or less.

This preferred method is for example performed by using a desired UV lamp or by using a band pass filter and/or a cut off filter, which is substantially transmissive for UV light having the respective desired wavelength and substantially blocks UV light having the respective undesired wavelength. For example, when irradiation of UV light having a wavelength λ of 300-400nm is desired, UV exposure may be performed using a broadband pass filter that is substantially transmissive for wavelengths of 300nm < λ <400 nm. When radiation of UV light having a wavelength λ greater than 340nm is desired, UV exposure may be performed using a cut-off filter that is substantially transmissive for λ >340nm wavelengths.

By "substantially transmissive" is meant that the filter transmits a majority, preferably at least 50%, of the intensity of incident light of the desired wavelength. By "substantially block" is meant that the filter does not transmit a substantial portion, preferably at least 50%, of the intensity of incident light of an undesired wavelength. "desired (undesired) wavelengths", for example in the case of a band-pass filter, means wavelengths within (outside) a given lambda range, and in the case of a cut-off filter, wavelengths above (below) a given lambda value.

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

The UV radiation energy is typically 6 to 100J, depending on the production process conditions.

The LC media used in the present invention preferably do consist essentially of polymerizable component a), or one or more polymerizable compounds of formula I as described above and below and LC component B) or LC host mixtures. However, the LC medium may additionally comprise one or more further components or additives, preferably selected from the list comprising, but not limited to: comonomers, chiral dopants, polymerization initiators, inhibitors, stabilizers, surfactants, wetting agents, lubricants, dispersants, hydrophobing agents, binders, flow improvers, defoamers, deaerators, diluents, reactive diluents, auxiliaries, colorants, dyes, pigments and nanoparticles.

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

Preference is furthermore given to LC media in which the polymerisable component A) comprises one, two or three polymerisable compounds of the formula II.

Preference is furthermore given to LC media in which the liquid-crystalline component B) or the LC host mixture has a nematic LC phase (at 20 ℃ C.), and preferably no chiral liquid-crystalline phase.

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

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

Preferably, the proportion of polymerizable component a) in the LC medium is >0 to < 5%, very preferably < 3%, more preferably 0.1 to 2.0, most preferably 0.2 to 1.0%.

Preferably, the proportion of the compounds of the formula I in the LC medium is >0 to < 5%, very preferably >0 to < 3%, more preferably 0.05 to 2.0, most preferably 0.1 to 0.6%.

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

Preferably, the proportion of the LC component B) in the LC medium is from 95 to < 100%, very preferably from 96.5 to < 100%, most preferably from 99 to < 100%. Component B) is non-polymerizable.

In addition to the polymerisable compounds described above, the LC medium for LC displays comprises an LC mixture ("host mixture") comprising one or more, preferably two or more, LC compounds selected from non-polymerisable low molecular weight compounds. These LC compounds are selected such that they are stable and/or non-reactive to the polymerization reaction under the conditions applied for the polymerization of the polymerizable compounds.

In principle, any LC mixture suitable for use in conventional displays is suitable as host mixture. Suitable LC mixtures are known to the person skilled in the art and are described in the literature, for example in the case of VA displays in EP 1378557 a1 and in the case of OCB displays in EP 1306418 a1 and DE 10224046 a 1.

The polymerisable compounds of formula I are particularly suitable for LC host mixtures comprising one or more mesogenic or LC compounds comprising alkenyl groups (hereinafter also referred to as "alkenyl compounds") which are stable to the polymerisation reaction under the conditions used for polymerising the compounds of formula I and for polymerising other polymerisable compounds comprised in the LC medium. Compared to RMs known from the prior art, the compounds of the formula I exhibit improved properties in this LC host mixture, such as solubility, reactivity or the ability to generate tilt angles.

Thus, in addition to the polymerisable compounds of formula I, the LC medium used in the present invention preferably comprises one or more mesogenic or liquid crystalline compounds comprising an alkenyl group ("alkenyl compounds"), wherein this alkenyl group is preferably stable to polymerisation under the conditions used for polymerising the polymerisable compound of formula I or for polymerising other polymerisable compounds comprised in the LC medium.

The alkenyl group in the alkenyl compound is preferably selected from straight-chain, branched or cyclic alkenyl groups having in particular 2 to 25C atoms, particularly preferably 2 to 12C atoms, in addition to one or more non-adjacent CH groups₂A group may be substituted by-O-, -S-, -CO-O-, -O-CO-O-in such a way that O atoms and/or S atoms are not directly linked to one another, and in addition, one or more H atoms may be substituted by F and/or Cl.

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

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

Particularly preferred are LC mixtures containing 1 to 5, preferably 1,2 or 3 compounds having an alkenyl group.

The mesogen and LC compounds containing alkenyl groups are preferably selected from the formulae AN and AY as defined below.

In addition to the polymerizable component a) as described above, the LC media used in the present invention 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 non-reactive to the polymerization reaction under the conditions applied for the polymerization of the polymerizable compounds.

In a first preferred embodiment, the LC medium contains an LC component B) or an LC host mixture based on a compound having a negative dielectric anisotropy. The LC medium is particularly suitable for PS-VA and PS-UB-FFS displays. Particularly preferred embodiments of this LC medium are those of the following sections a) to z 3):

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

wherein

a represents a number of 1 or 2,

b represents a number of 0 or 1,

to represent

R¹And R²Each independently of the other represents an alkyl radical having 1 to 12C atoms, wherein furthermore one or two non-adjacent CH groups₂The radicals may also be replaced by-O-, -CH-, -CO-, -OCO-or-COO-in such a way that the O atoms are not linked directly to one another, preferably alkyl or alkoxy having from 1 to 6 carbon atoms,

Z^xand Z^yEach independently of the other represents-CH₂CH₂-、-CH＝CH-、-CF₂O-、-OCF₂-、-CH₂O-、-OCH₂-、-CO-O-、-O-CO-、-C₂F₄-、-CF＝CF-、-CH＝CH-CH₂O-or a single, preferably single,

L^1-4each independently of the others represents F, Cl, OCF₃、CF₃、CH₃、CH₂F、CHF₂。

Preferably, L¹And L²Both represent F, or L¹And L²One of them represents F and the other represents Cl, or L³And L⁴Both represent F, or L³And L⁴One of them represents F and the other represents Cl.

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

wherein a represents 1 or 2, alkyl and alkyl^*Each independently of the others, represents a linear alkyl group having 1 to 6C atoms, and alkinyl represents a linear alkenyl group having 2 to 6C 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-。

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

wherein a lkyl and alkyl^*Each independently of the others, represents a linear alkyl group having 1 to 6C atoms, and alkinyl represents a linear alkenyl group having 2 to 6C 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-。

b) LC medium, wherein said component B) or LC host mixture comprises one or more mesogenic or LC compounds (hereinafter also referred to as "alkenyl compounds") comprising alkenyl groups, wherein said alkenyl groups are stable to polymerization under the polymerization conditions used for the polymerizable compounds contained in the LC medium.

Preferably, component B) or the LC host mixture comprises one or more alkenyl compounds selected from the group consisting of AN and AY

Wherein the individual radicals are identical or different on each occurrence and each, independently of one another, has the following meanings:

to represent

To represent

To represent

R^A1Is alkenyl having 2 to 9C atoms, or R if at least one of rings X, Y and Z represents cyclohexenyl^A1Also has R^A2In one of the meaning of (a),

R^A2is alkyl having 1 to 12C atoms, wherein furthermore one or two non-adjacent CH' s₂The radicals are replaced by-O-, -CH ═ CH-, -CO-, -OCO-or-COO-in such a way that the O atoms are not linked directly to one another,

Z^xis-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,

L^1,2is H, F, Cl, OCF₃、CF₃、CH₃、CH₂F or CHF₂H, preferably H, F or Cl,

x is 1 or 2, and the compound is,

z is 0 or 1.

Preferred compounds of the formulae AN and AY are those in which R^A2Selected from the group consisting of ethenyl, propenyl, butenyl, pentenyl, hexenyl, and heptenyl.

In a preferred embodiment, component B) or the LC host mixture comprises one or more compounds of formula AN selected from the following subformulae:

wherein alkyl and alkyl^*Each independently of the other represents a linear alkyl radical having 1 to 6C atoms, and alkinyl^*Each independently of the others, represents a linear alkenyl group having 2 to 7C atoms. alkinyl and alkinyl^*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-。

Preferably, component B) or the LC host mixture comprises one or more compounds selected from the group consisting of compounds of formula AN1, AN2, AN3 and AN6, very preferably one or more compounds of formula AN 1.

In another preferred embodiment, component B) or the LC host mixture comprises one or more compounds of formula AN selected from the following subformulae:

wherein m represents 1,2,3,4, 5 or 6, i represents 0,1,2 or 3, and R^b1Representative H, CH₃Or C₂H₅。

In another preferred embodiment, component B) or the LC host mixture comprises one or more compounds selected from the following subformulae:

most preferred are compounds of formula AN1a2 and AN1a 5.

In another preferred embodiment, component B) or the LC host mixture comprises one or more compounds of formula AY selected from the following subformulae:

wherein alkyl and alkyl^*Each independently of the other represents a straight-chain alkyl group having 1 to 6C atoms, "(O)" represents an O-atom or a single bond, and alkinyl^*Each independently of the others, represents a linear alkenyl group having 2 to 7C atoms. alkinyl and alkinyl^*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-。

In another preferred embodiment, component B) or the LC host mixture comprises one or more compounds of formula AY selected from the following subformulae:

wherein m and n each, independently of one another, denote 1,2,3,4, 5 or 6, and alkinyl denotes CH₂＝CH-、CH₂＝CHCH₂CH₂-、CH₃-CH＝CH-、CH₃-CH₂-CH＝CH-、CH₃-(CH₂)₂-CH＝CH-、CH₃-(CH₂)₃-CH ═ CH-or CH₃-CH＝CH-(CH₂)₂-。

Preferably, the proportion of compounds of the formulae AN and AY in the LC medium is from 2 to 70% by weight, very preferably from 5 to 60% by weight, most preferably from 10 to 50% by weight.

Preferably, the LC medium or LC host mixture contains 1 to 5, preferably 1,2 or 3 compounds selected from the group consisting of formula AN and AY.

In another preferred embodiment of the invention, the LC medium comprises one or more compounds of formula AY14, very preferably AY14 a. The proportion of the compounds of the formulae AY14 and AY14a in the LC medium is preferably from 3 to 20% by weight.

The addition of alkenyl compounds of the formula AN and/or AY makes it possible to reduce the viscosity and the response time of the LC medium.

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

wherein the individual radicals have the following meanings:

to represent

To represent

R³And R⁴Each independently of the other represents an alkyl radical having 1 to 12C atoms, in which furthermore one or two non-adjacent CH groups₂A group may also be replaced by-O-, -CH ═ CH-, -CO-, -O-CO-, or-CO-O-in such a way that the O atoms are not directly attached to each other,

Z^yrepresents-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.

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

wherein alkyl and alkyl^*Each independently of the others, represents a linear alkyl group having 1 to 6C atoms, and alkinyl represents a linear alkenyl group having 2 to 6C 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-。

Especially preferred are compounds of formula ZK 1.

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

wherein propyl, butyl and pentyl are linear groups.

Most preferred are compounds of formula ZK1 a.

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

wherein the individual radicals, identically or differently on each occurrence, have the following meanings:

R⁵and R⁶Each independently of the other represents an alkyl radical having 1 to 12C atoms, wherein furthermore one or two non-adjacent CH groups₂The radicals may be replaced by-O-, -CH ═ CH-, -CO-, -OCO-or-COO-in such a way that O atoms are not linked directly to one another, preferably alkyl or alkoxy having 1 to 6C atoms,

to represent

To represent

And are and

e represents 1 or 2.

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

wherein alkyl and alkyl^*Each independently of the other represents a linear alkyl radical having 1 to 6C atoms, and alkinyl represents a linear alkenyl radical having 2 to 6C 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-。

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

wherein the individual radicals have the following meanings:

d represents ot

Wherein at least one ring F is different from cyclohexylene.

f represents a number of 1 or 2,

R¹and R²Each independently of the other represents an alkyl radical having 1 to 12C atoms, wherein furthermore one or two non-adjacent CH groups₂A group may be replaced by-O-, -CH ═ CH-, -CO-, -OCO-, or-COO-in such a way that the O atoms are not directly linked to each other,

Z^xrepresents-CH₂CH₂-、-CH＝CH-、-CF₂O-、-OCF₂-、-CH₂O-、-OCH₂-、-CO-O-、-O-CO-、-C₂F₄-、-CF＝CF-、-CH＝CH-CH₂O-or a single, preferably single,

L¹and L²Each independently of the others represents F, Cl, OCF₃、CF₃、CH₃、CH₂F、CHF₂。

Preferably, two radicals L¹And L²Represents F, or a group L¹And L²One of them represents F and the other represents Cl.

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

wherein R is¹Has the meaning given above, alkyl represents a straight-chain alkyl group having 1 to 6C atoms, (O) represents an oxygen atom or a single bond, and v represents an integer of 1 to 6. R¹Preferably represents a straight-chain alkyl group having 1 to 6C atoms or a straight-chain alkenyl group having 2 to 6C atoms, in particular CH₃、C₂H₅、n-C₃H₇、n-C₄H₉、n-C₅H₁₁、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-。

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

wherein alkyl represents C_1-6Alkyl radical, L^xRepresents H or F, and X represents F, Cl, OCF₃、OCHF₂Or OCH ═ CF₂. Particular preference is given to compounds of the formula G1, wherein X denotes F.

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

wherein R is⁵Having the foregoing for R¹In one of the meanings given, alkyl represents C_1-6-alkyl, d represents 0 or 1, and z and m each, independently of the others, represent an integer from 1 to 6. R in these compounds⁵Particularly preferably C_1-6-alkyl or-alkoxy or C_2-6-alkenyl, d is preferably 1. The LC medium according to the invention preferably comprises one or more compounds of the above-mentioned formula in an amount of > 5% by weight.

h) LC media, wherein component B) or the LC host mixture additionally comprises one or more biphenyl compounds selected from the group consisting of the following formulae:

wherein alkyl and alkyl^*Each independently of the other represents a linear alkyl radical having 1 to 6C atoms, and alkinyl^*Each independently of the other represents 2 to 6A linear alkenyl group of a C atom. alkinyl and alkinyl^*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-。

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

The compounds of the formula B2 are particularly preferred.

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

wherein the alkyl radical^*Represents an alkyl group having 1 to 6C atoms. The media according to the invention particularly preferably comprise one or more compounds of the formulae B1a and/or B2 c.

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

wherein R is⁵And R⁶Each independently of the other having one of the meanings indicated above and

each independently of the other represents:

wherein L is⁵Represents F or Cl, preferably F, and L⁶Represents F, Cl, OCF₃、CF₃、CH₃、CH₂F or CHF₂Preferably F.

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

wherein R represents a linear alkyl or alkoxy group having 1 to 7C atoms, R^*Represents a linear alkenyl group having 2 to 7C atoms, (O) represents an oxygen atom or a single bond, and m represents an integer of 1 to 6. R^*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-。

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

The LC host mixtures according to the invention preferably comprise terphenyls of the formula T and their preferred subformulae, preferably in an amount of from 0.5 to 30% by weight, in particular from 1 to 20% by weight.

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

If the Δ n value of the mixture is ≧ 0.1, terphenyl is preferably used in the LC medium according to the invention. Preferred LC media comprise 2-20 wt.% of one or more terphenyl compounds of formula T, preferably selected from compounds T1 to T22.

k) LC media, wherein component B) or the LC host mixture additionally comprises one or more quaterphenyl compounds selected from the group consisting of the following formulae:

wherein

R^QIs alkyl, alkoxy, oxaalkyl or alkoxyalkyl having 1 to 9C atoms, or alkenyl or alkenyloxy having 2 to 9C atoms, all of which are optionally fluorinated,

X^Qis F, Cl, haloalkyl or alkoxy having 1 to 6C atoms, or haloalkenyl or alkenyloxy having 2 to 6C atoms,

L^Q1to L^Q6Independently of one another are H or F, wherein L^Q1To L^Q6Is F.

Preferred compounds of formula Q are those wherein R is^QThose representing straight-chain alkyl groups having 2 to 6C atoms (ethyl, n-propyl or n-butyl being very preferred).

Preferred compounds of formula Q are those wherein L^Q3And L^Q4Those that are F. Further preferred compounds of the formula Q are those in which L^Q3、L^Q4And L^Q1And L^Q2One or both of which are those of F.

Preferred compounds of formula Q are those wherein X^QRepresents F or OCF₃(very preferably F).

The compound of formula Q is preferably selected from the following subformulae

Wherein R is^QHas 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.

Especially preferred are compounds of formula Q1, especially wherein R^QThose which are n-propyl.

Preferably, the proportion of compounds of the formula Q in the LC host mixture is from >0 to ≦ 5 wt.%, very preferably 0.1 to 2 wt.%, most preferably 0.2 to 1.5 wt.%.

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

The addition of the quaterphenyl compound of formula Q to the LC host mixture can reduce ODF inhomogeneity while maintaining high UV absorption, can enable fast and complete polymerization, can enable strong and fast tilt angle generation, and increase the UV stability of the LC medium.

Furthermore, the addition of the compound of formula Q having positive dielectric anisotropy to an LC medium having negative dielectric anisotropy allows better control of the values of the dielectric constants | | and | |, in particular enabling high values of the dielectric constants | | | while keeping the dielectric anisotropy Δ constant, thereby reducing kickback voltage and reducing image sticking.

l) an LC medium in which component B) or the LC host mixture additionally comprises one or more compounds of the formula C:

wherein

R^CRepresents alkyl, alkoxy, oxaalkyl or alkoxyalkyl having 1 to 9C atoms, or alkenyl or alkenyloxy having 2 to 9C atoms, all of which are optionally fluorinated,

X^Crepresents F, Cl, a haloalkyl or alkoxy group having 1 to 6C atoms, or a haloalkenyl or alkenyloxy group having 2 to 6C atoms,

L^C1、L^C2independently of one another, H or F, wherein L^C1And L^C2Is F.

Preferred compounds of the formula C are those in which R^CThose representing straight-chain alkyl groups having 2 to 6C atoms (ethyl, n-propyl or n-butyl being very preferred).

Preferred compounds of the formula C are those wherein L^C1And L^C2Those that are F.

Preferred compounds of the formula C are those in which X^CRepresents F or OCF₃(very preferably F).

Preferred compounds of formula C are selected from the following formulae

Wherein R is^CHas one of the meanings of the 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.

Preferably, the proportion of compounds of the formula C in the LC host mixture is >0 to ≦ 10 wt.%, very preferably 0.1 to 8 wt.%, most preferably 0.2 to 5 wt.%.

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

Addition of compounds of the formula C having a positive dielectric anisotropy to LC media having a negative dielectric anisotropy allows a better control of the dielectric constants | | and_⊥in particular, a high dielectric constant can be achieved_||The value while keeping the dielectric anisotropy Δ constant reduces the kickback voltage and reduces image sticking. Furthermore, the addition of the compounds of the formula C makes it possible to reduce the viscosity and the response time of the LC medium.

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

wherein R is¹And R²Have the meaning indicated above and preferably each independently of one another denote a straight-chain alkyl radical having 1 to 6C atoms or a straight-chain alkenyl radical having 2 to 6C atoms.

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

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

wherein

To represent

R⁹Representation H, CH₃、C₂H₅Or n-C₃H₇(F) represents an optional fluoro substituent, and q represents 1,2 or 3, and R⁷Having a function of R¹In one of the indicated meanings, preferably in an amount of>3% by weight, in particular ≥ 5% by weight, very particularly preferably 5-30% by weight.

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

wherein R is⁷Preferably represents a straight-chain alkyl group, and R⁹Represents CH₃、C₂H₅Or n-C₃H₇. Particularly preferred are compounds of the formulae FI1, FI2 and FI 3.

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

wherein R is⁸Having a function of R¹The meaning indicated, and alkyl denotes straight-chain alkyl groups having 1 to 6C atoms.

p) an 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 the following formulae:

wherein

R¹⁰And R¹¹Each independently of the other represents an alkyl radical having 1 to 12C atoms, wherein furthermore one or two non-adjacent CH groups₂The radicals may be replaced by-O-, -CH ═ CH-, -CO-, -OCO-or-COO-in such a way that O atoms are not linked directly to one another, preferably alkyl or alkoxy having 1 to 6C atoms,

and R is¹⁰And R¹¹Preferably represents a straight-chain alkyl or alkoxy group having 1 to 6C atoms, or a straight-chain alkenyl group having 2 to 6C atoms, and

Z¹and Z²Each independently of the other 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.

q) an LC medium wherein component B) or the LC host mixture additionally comprises one or more difluorodibenzochromans and/or chromans of the formula:

wherein

R¹¹And R¹²Each independently of the other having the above for R¹¹In one of the meanings indicated, the compound is,

ring M is trans-1, 4-cyclohexylene or 1, 4-phenylene,

Z^mis-C₂H₄-、-CH₂O-、-OCH₂-, -CO-O-or-O-CO-,

c is 0,1 or 2,

preferably, it is present in an amount of from 3 to 20% by weight, in particular in an amount of from 3 to 15% by weight.

r) an LC medium, wherein component B) or the LC host mixture additionally comprises one or more fluorinated phenanthrenes, dibenzofurans and/or dibenzothiophenes of the formula, in particular BF or BS:

wherein R is¹¹And R¹²Each independently of the other having the above for R¹¹In one of the indicated meanings, b represents 0 or 1, L represents F and r represents 1,2 or 3.

Particularly preferred compounds of formulae PH, BF and BS are selected from the group consisting of the following subformulae:

wherein R and R' each independently of one another represent a straight-chain alkyl or alkoxy radical having 1 to 7C atoms.

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

Wherein

R¹And R²Each independently of the other represents an alkyl radical having 1 to 12C atoms, wherein furthermore one or two non-adjacent CH groups₂The radicals may be replaced by-O-, -CH-, -CO-, -OCO-or-COO-in such a way that O atoms are not bonded directly to one another, preferably alkyl or alkoxy having 1 to 6C atoms,

L¹and L²Each independently of the others represents F, Cl, OCF₃、CF₃、CH₃、CH₂F、CHF₂。

Preferably, L¹And L²Both represent F, or L¹And L²One of which represents F and the other represents Cl,

the compound of formula Y is preferably selected from the group consisting of the following subformulae:

among them, Alkyl and Alkyl^*Each independently of the others, a straight-chain alkyl radical having 1 to 6C atoms, Alkoxyl a straight-chain alkoxy radical having 1 to 6C atoms, alkinyl and alkinyl^*Each independently of the others, represents a linear alkenyl group having 2 to 6C atoms, and O represents an oxygen atom or a single bond. Alkinyl and alkinyl^*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-。

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

wherein alkOXyl preferably denotes straight-chain alkoxy having 3,4 or 5C atoms.

t) LC media which, apart from the polymerisable compounds as described above and below, does not comprise a compound containing a compound having a terminal ethyleneoxy group (-O-CH ═ CH)₂) The compound of (1).

u) an LC medium, wherein component B) or the LC host mixture comprises 1 to 8, preferably 1 to 5, compounds of the formulae CY1, CY2, PY1 and/or PY 2. The proportion of these compounds in the entire LC host mixture is preferably from 5 to 60%, particularly preferably from 10 to 35%. The content of these individual compounds is preferably from 2 to 20% in each case.

v) an LC medium, wherein component B) or the LC host mixture comprises 1 to 8, preferably 1 to 5, compounds of the formulae CY9, CY10, PY9 and/or PY 10. The proportion of these compounds in the entire LC host mixture is preferably from 5 to 60%, particularly preferably from 10 to 35%. The content of these individual compounds is preferably from 2 to 20% in each case.

w) an LC medium, wherein 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 formulae ZK1, ZK2 and/or ZK 6. The proportion of these compounds in the entire LC host mixture is preferably from 3 to 25%, particularly preferably from 5 to 45%. The content of these individual compounds is preferably from 2 to 20% in each case.

x) an LC medium, wherein the proportion of compounds of formulae CY, PY and ZK is more than 70%, preferably more than 80%, in the entire LC host mixture.

y) AN LC medium, wherein the LC host mixture comprises one or more compounds containing alkenyl groups, preferably selected from the group consisting of the formulae AN and AY, very preferably from the formulae AN1, AN3, AN6 and AY14, most preferably from the formulae AN1a, AN3a, AN6a and AY 14. The concentration of these compounds in the LC host mixture is preferably 2-70%, very preferably 3-55%.

z) an LC medium, wherein component B) or the LC host mixture contains one or more, preferably 1 to 5, compounds selected from the group of the formulae PY1-PY8 (very preferably of the formula PY 2). The proportion of these compounds in the entire LC host mixture is preferably from 1 to 30%, particularly preferably from 2 to 20%. The content of these individual compounds is preferably in each case from 1 to 20%.

z1) LC media wherein component B) or the LC host mixture contains one or more, preferably 1,2 or 3, compounds selected from the group consisting of the compounds of the formulae T1, T2 and T5, very preferably from the group of the compounds of the formula T2. The proportion of these compounds in the entire LC host mixture is preferably 1 to 20%.

z2) AN LC medium wherein the LC host mixture comprises one or more compounds selected from the group consisting of formula CY and PY, one or more compounds selected from the group consisting of formula AN and AY, and one or more compounds selected from the group consisting of formula T and Q.

z3) LC medium, wherein the LC host mixture contains one or more, preferably 1,2 or 3, compounds of the formula BF1 and one or more, preferably 1,2 or 3, compounds selected from the group of the compounds of the formulae AY14, AY15 and AY16, very preferably a compound of the formula AY 14. The proportion of the compound of formula AY14-AY16 in the LC host mixture is preferably 2-35%, very preferably 3-30%. The proportion of the compound of the formula BF1 in the LC host mixture is preferably from 0.5 to 20%, very preferably from 1 to 15%. Further preferably, the LC host mixture according to this preferred embodiment contains one or more, preferably 1,2 or 3 compounds of formula T, preferably selected from the group consisting of formulae T1, T2 and T5, very preferably selected from the group consisting of formulae T2 or T5. The proportion of the compound of the formula T in the LC host mixture is preferably from 0.5 to 15%, very preferably from 1 to 10%.

In a second preferred embodiment, the LC medium contains an LC host mixture based on a compound having positive dielectric anisotropy. Such LC media are particularly suitable for PS-OCB-, PS-TN-, PS-positive-VA-, PS-IPS-or PS-FFS-displays.

Wherein the radicals, independently of one another and identically or differently at each occurrence, have the following meanings:

each independently of the other

And each occurrence, identically or differently, is

R²¹、R³¹Each independently of the others, being alkyl, alkoxy, oxaalkyl or alkoxyalkyl having 1 to 9C atoms, or alkenyl or alkenyloxy having 2 to 9C atoms, all of which are optionally fluorinated,

X⁰f, Cl, haloalkyl or alkoxy having 1 to 6C atoms, or haloalkenyl or alkenyloxy having 2 to 6C atoms,

Z³¹is-CH₂CH₂-、-CF₂CF₂-, -COO-, trans-CH-, trans-CF-, -CH₂O-or a single bond, preferably-CH₂CH₂-, -COO-, trans-CH-or a single bond, particularly preferably-COO-, trans-CH-or a single bond,

L²¹、L²²、L³¹、L³²each independently of the other represents H or F,

g is 0,1,2 or 3.

In the compounds of the formulae A and B, X⁰Preferably F, Cl, CF₃、CHF₂、OCF₃、OCHF₂、OCFHCF₃、OCFHCHF₂、OCFHCHF₂、OCF₂CH₃、OCF₂CHF₂、OCF₂CHF₂、OCF₂CF₂CHF₂、OCF₂CF₂CHF₂、OCFHCF₂CF₃、OCFHCF₂CHF₂、OCF₂CF₂CF₃、OCF₂CF₂CClF₂、OCClFCF₂CF₃Or CH ═ CF₂Very preferably F or OCF₃Most preferably, F.

In the compounds of the formulae A and B, R²¹And R³¹Preferably selected from straight chain alkyl or alkoxy groups having 1,2,3,4, 5 or 6C atoms, and straight chain alkenyl groups having 2,3,4, 5,6 or 7C atoms.

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

In the compounds of the formula B, Z³¹Preferably COO, trans-CH ═ CH or a single bond, and very preferably COO or a single bond.

Preferably, component B) of the LC medium comprises one or more compounds of formula a selected from the group consisting of:

wherein A is²¹、A²²、R²¹、X⁰、L²¹And L²²Having the meaning given in formula A, L²³And L²⁴Each independently of the other being H or F, and X⁰Preferably F. Especially preferred are compounds of formulae a1 and a 2.

Particularly preferred compounds of formula a1 are selected from the group consisting of the following subformulae:

wherein R is²¹、X⁰、L²¹And L²²Has the meaning given in formula A1, L²³、L²⁴、L²⁵And L²⁶Each independently of the other being H or F, and X⁰Preferably F.

Very particularly preferred compounds of formula a1 are selected from the group consisting of the following subformulae:

wherein R is²¹As defined in formula a 1.

Particularly preferred compounds of formula a2 are selected from the group consisting of the following subformulae:

wherein R is²¹、X⁰、L²¹And L²²Has the meaning given in formula A2, L²³、L²⁴、L²⁵And L²⁶Each independently of the other being H or F, and X⁰Preferably F.

Very particularly preferred compounds of formula a2 are selected from the group consisting of the following subformulae:

wherein R is²¹And X⁰As defined in formula a 2.

Particularly preferred compounds of formula a3 are selected from the group consisting of the following subformulae:

wherein R is²¹、X⁰、L²¹And L²²Has the meaning given in formula A3, and X⁰Preferably F.

Preferably, component B) of the LC medium comprises one or more compounds of formula B selected from the group consisting of:

wherein g and A³¹、A³²、R³¹、X⁰、L³¹And L³²Having the meaning given in formula B, and X⁰Preferably F. Particularly preferred are compounds of formulae B1 and B2.

Particularly preferred compounds of formula B1 are selected from the group consisting of the following subformulae:

wherein R is³¹、X⁰、L³¹And L³²Has the meaning given in formula B1, and X⁰Preferably F.

Very particularly preferred compounds of formula B1a are selected from the group consisting of the following subformulae:

wherein R is³¹As defined in formula B1.

Very particularly preferred compounds of formula B1B are selected from the group consisting of the following subformulae:

wherein R is³¹As defined in formula B1.

Particularly preferred compounds of formula B2 are selected from the group consisting of the following subformulae:

wherein R is³¹、X⁰、L³¹And L³²Has the meaning given in formula B2, L³³、L³⁴、L³⁵And L³⁶Each independently of the other being H or F, and X⁰Preferably F.

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

wherein R is³¹As defined in formula B2.

Very particularly preferred compounds of formula B2B are selected from the group consisting of the following subformulae:

wherein R is³¹As defined in formula B2.

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

wherein R is³¹As defined in formula B2.

Very particularly preferred compounds of formulae B2d and B2e are selected from the group consisting of the following subformulae:

wherein R is³¹As defined in formula B2.

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

wherein R is³¹As defined in formula B2.

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

wherein R is³¹As defined in formula B2.

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

wherein R is³¹As defined in formula B2.

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

wherein R is³¹As defined in formula B2.

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

wherein R is³¹As defined in formula B2.

Alternatively, or in addition to the compounds of the formulae B1 and/or B2, component B) of the LC medium may also comprise one or more compounds of the formula B3 as defined above.

Preferably, component B) of the LC medium comprises, in addition to the compounds of formula a and/or B, one or more compounds of formula C:

wherein the individual radicals have the following meanings:

each independently of the other, and

each occurrence, identically or differently, is

R⁴¹、R⁴²Each independently of the others, being alkyl, alkoxy, oxaalkyl or alkoxyalkyl having 1 to 9C atoms, or alkenyl or alkenyloxy having 2 to 9C atoms, all of which are optionally fluorinated,

Z⁴¹、Z⁴²each independently of the other being-CH₂CH₂-, -COO-, trans-CH-, trans-CF-, -CH₂O-、-CF₂O-, -C.ident.C-or a single, preferably single, bond,

h is 0,1,2 or 3.

In the compound of formula C, R⁴¹And R⁴²Preferably selected from straight chain alkyl or alkoxy groups having 1,2,3,4, 5 or 6C atoms, and straight chain alkenyl groups having 2,3,4, 5,6 or 7C atoms.

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

In the compound of formula C, Z⁴¹And Z⁴²Preferably selected from COO, trans-CH ═ CH and single bonds, and very preferably from COO and single bonds.

Preferred compounds of formula C are selected from the group consisting of the following subformulae:

wherein R is⁴¹And R⁴²Have the meaning given in formula C and preferably each, independently of one another, denote alkyl, alkoxy, fluoroalkyl or fluoroalkoxy having 1 to 7C atoms or alkenyl, alkenyloxy, alkoxyalkyl or fluoroalkenyl having 2 to 7C atoms.

Preferably, component B) of the LC medium comprises, in addition to the compounds of the formulae A and/or B, one or more compounds of the formula D

Wherein A is⁴¹、A⁴²、Z⁴¹、Z⁴²、R⁴¹、R⁴²And h has the meaning given in formula C or one of the preferred meanings given above.

Preferred compounds of formula D are selected from the group consisting of the following subformulae:

wherein R is⁴¹And R⁴²Has the meaning given in formula D and R⁴¹Preferably represents an alkyl group, and R in the formula D1⁴²Preferably represents an eneRadical, particularly preferably represents- (CH)₂)₂-CH＝CH-CH₃And in the formula D2, R⁴²Preferably represents an alkyl group, - (CH)₂)₂-CH＝CH₂Or- (CH)₂)₂-CH＝CH-CH₃。

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

Wherein the individual radicals, which are identical or different at each occurrence, each, independently of one another, have the following meanings:

to represent

To represent

R^A1Is alkenyl having 2 to 9C atoms, or R if at least one of rings X, Y and Z represents cyclohexenyl^A1And also has R^A2In one of the meaning of (a),

R^A2is alkyl having 1 to 12C atoms, wherein furthermore one or two non-adjacent CH' s₂The radicals may be substituted by-O-, -CH-, -CO-, -OCO-or-COO-is replaced in such a way that the O atoms are not directly linked to each other,

x is 1 or 2.

R^A2Preferred are straight-chain alkyl or alkoxy groups having 1 to 8C atoms, or straight-chain alkenyl groups having 2 to 7C atoms.

Preferred compounds of formula E are selected from the following subformulae:

wherein alkyl and alkyl^*Each independently of the other represents a linear alkyl radical having 1 to 6C atoms, and alkinyl^*Each independently of the others, represents a linear alkenyl group having 2 to 7C atoms. alkinyl and alkinyl^*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-。

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

wherein m represents 1,2,3,4, 5 or 6, i represents 0,1,2 or 3, and R^b1Representation H, CH₃Or C₂H₅。

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

most preferred are compounds of formula E1a2, E1a5, E3a1 and E6a 1.

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

Wherein the radicals, independently of one another and identically or differently at each occurrence, have the following meanings:

to represent

R²¹、R³¹Each independently of the others, being alkyl, alkoxy, oxaalkyl or alkoxyalkyl having 1 to 9C atoms, or alkenyl or alkenyloxy having 2 to 9C atoms, all of which are optionally fluorinated,

X⁰f, Cl, haloalkyl or alkoxy having 1 to 6C atoms, or haloalkenyl or alkenyloxy having 2 to 6C atoms,

Z²¹is-CH₂CH₂-、-CF₂CF₂-, -COO-, trans-CH-, trans-CF-, -CH₂O-or a single bond, preferably-CH₂CH₂-, -COO-, trans-CH-or a single bond, particularly preferably-COO-, trans-CH-or a single bond,

L²¹、L²²、L²³、L²⁴each independently of the other represents H or F,

g is 0,1,2 or 3.

Particularly preferred compounds of formula F are selected from the group consisting of:

wherein R is²¹、X⁰、L²¹And L²²Has the meaning given in formula F, L²⁵And L²⁶Each independently of the other represents H or F, and X⁰Preferably F.

The concentration of the compounds of formulae a and B in the LC host mixture is preferably 2-60%, very preferably 3-45%, most preferably 4-35%.

The concentration of the compounds of formulae C and D in the LC host mixture is preferably 2-70%, very preferably 5-65%, most preferably 10-60%.

The concentration of the compound of formula E in the LC host mixture is preferably 5-50%, very preferably 5-35%.

The concentration of the compound of formula F in the LC host mixture is preferably 2-30%, very preferably 5-20%.

Further preferred embodiments of this second preferred embodiment of the present invention are listed below, including any combination thereof.

2a) The LC host mixture comprises one or more compounds of the formulae a and/or B having a positive dielectric anisotropy, preferably Δ > 15.

2b) The LC host mixture comprises one or more compounds selected from the group consisting of formula A1A2, A1B1, A1d1, A1F1, A2A1, A2h1, A2l2, A2k1, B2h3, B2l1, F1 a. The proportion of these compounds in the LC host mixture is preferably from 4 to 40%, very preferably from 5 to 35%.

2c) The LC host mixture comprises one or more compounds selected from the group consisting of formula B2C1, B2C4, B2f4, C14. The proportion of these compounds in the LC host mixture is preferably from 4 to 40%, very preferably from 5 to 35%.

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

2e) The LC host mixture comprises one or more compounds selected from the group consisting of compounds of formulae E1, E3 and E6 (preferably E1a, E3a and E6a, very preferably E1a2, E1a5, E3a1 and E6a 1). The proportion of these compounds in the LC host mixture is preferably from 5 to 60%, very preferably from 10 to 50%.

The combination of the compounds of the preferred embodiment described above with the above-described polymeric compounds results in a low threshold voltage, a low rotational viscosity and very good low-temperature stability in the LC media according to the invention, together with a high clearing point and a high HR value, and allows particularly low tilt angles to be established quickly in PSA displays. In particular, the LC media exhibit significantly reduced response times, in particular also gray scale response times, in PSA displays compared to the media of the prior art.

The LC media and LC host mixtures according to the invention preferably have a nematic phase range of at least 80K, particularly preferably at least 100K, and a rotational viscosity of 250 mPas or less, preferably 200 mPas or less, at 20 ℃.

In the VA-type display according to the invention, the molecules in the layers of the LC medium are aligned perpendicular to the electrode surfaces (homeotropically) or have a tilted homeotropic alignment in the switched-off state. When a voltage is applied to the electrodes, the LC molecules are realigned and the longitudinal molecular axes are parallel to the electrode surfaces.

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

The birefringence Δ n of the LC media used in the PS-VA, PS-UB-FFS and SA-VA type displays according to the invention is preferably less than 0.16, particularly preferably from 0.06 to 0.14, very particularly preferably from 0.07 to 0.13.

In the OCB-type display according to the invention, the molecules in the layer of the LC medium have a "bent" alignment. Upon application of a voltage, re-alignment of the LC molecules occurs with the longitudinal molecular axes perpendicular to the electrode surface.

The LC media according to the invention which are suitable for use in PS-TN, PS-positive-VA, PS-IPS, PS-FFS and SA-FFS type displays preferably have a positive dielectric anisotropy Δ at 20 ℃ and 1kHz of from +2 to +30, particularly preferably from +3 to +20, based on compounds having a positive dielectric anisotropy according to the second preferred embodiment.

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

The birefringence Δ n of the LC media according to the invention for use in PS-TN, PS-positive-VA, PS-IPS, PS-FFS and SA-FFS type displays is preferably from 0.07 to 0.15, particularly preferably from 0.08 to 0.13.

The LC media according to the invention may also comprise further additives known to the person skilled in the art and described in the literature, such as polymerization initiators, inhibitors, stabilizers, surface-active substances or chiral dopants. These may be polymerizable or non-polymerizable. The polymerizable additive is thus classified as polymerizable component or component a). Non-polymerizable additives are therefore classified as non-polymerizable component or component B).

In addition, it is possible to add, for example, from 0 to 15% by weight of pleochroic dyes and, in addition, nanoparticles, conductive salts, preferably ammonium ethyldimethyldodecyl 4-hexyloxybenzoate, ammonium tetrabutyltetraphenylborate or complex salts of crown ethers, to the LC medium (see, for example, Haller et al, mol.24249-258(1973)) for improving the conductivity or adding substances for changing the dielectric anisotropy, viscosity and/or alignment of the nematic phase. Substances of this type are described, for example, in DE-A2209127, 2240864, 2321632, 2338281, 2450088, 2637430 and 2853728.

The individual components of preferred embodiments a) to z) of the LC media according to the invention are known or processes for the preparation thereof can be derived from the prior art by the person skilled in the relevant art, since they are based on standard methods described in the literature. Corresponding compounds of the formulｃA CY are described, for example, in EP-A-0364538. Corresponding compounds of the formula ZK are described, for example, in DE-A-2636684 and DE-A-3321373.

The LC media which can be used according to the invention are prepared in a manner conventional per se, for example by mixing one or more of the above-mentioned compounds with one or more polymerisable compounds as defined above, and optionally with further liquid-crystalline compounds and/or additives. In general, the desired amount of the components used in lesser amounts is dissolved in the components making up the main constituent, which is advantageously carried out at elevated temperature. It is also possible to mix solutions of the components in an organic solvent, for example acetone, chloroform or methanol, and to remove the solvent again, for example by distillation, after thorough mixing. The invention also relates to a method for producing the LC medium according to the invention.

It is obvious to the person skilled in the art that the LC media according to the invention may also contain, for example, compounds in which H, N, O, Cl, F are replaced by the corresponding isotopes, for example deuterium.

The following examples illustrate the invention but do not limit it. However, they show the person skilled in the art the preferred concept of mixtures, as well as the compounds preferably used and their respective concentrations, and also their combinations with one another. Furthermore, the examples illustrate which properties and combinations of properties are available.

Preferred mixture components are shown in tables a1 and a2 below. The compounds shown in table a1 are particularly suitable for use in LC mixtures having positive dielectric anisotropy. The compounds shown in table a2 are particularly suitable for use in LC mixtures having negative dielectric anisotropy.

TABLE A1

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_mH_2m+1Means C_mH_2m+1Or OC_mH_2m+1。

TABLE A2

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_mH_2m+1Means C_mH_2m+1Or OC_mH_2m+1。

In a first preferred embodiment of the present invention, the LC media according to the present invention (especially those having positive dielectric anisotropy) comprise one or more compounds selected from the group consisting of the compounds from table a 1.

In a second preferred embodiment of the present invention, the LC media according to the present invention (especially those having negative dielectric anisotropy) comprise one or more compounds selected from the group consisting of the compounds from table a 2.

TABLE B

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

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

Watch C

Table C shows possible stabilizers that can be added to the LC media according to the present invention. Wherein n represents an integer from 1 to 12, preferably 1,2,3,4, 5,6, 7 or 8, and does not show a terminal methyl group.

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

Table D

Table D shows illustrative reactive mesogenic compounds that can be used as polymerizable compounds in LC media according to the invention.

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

TABLE E

Table E shows self-alignment additives for homeotropic alignment that can be used with the polymerizable compounds of formula I in the LC process according to the present invention:

in a preferred embodiment, the LC medium and the display comprise one or more SA additives selected from the group consisting of the formulae SA-1 to SA-48, preferably from the formulae SA-14 to SA-48, very preferably from the formulae SA-20 to SA-34 and SA-44 to SA-47, and one or more RMs of the formula I. Very much preferred is a combination of: the combination of polymerizable compound 1,2 or 3 of example 1, below, very preferably polymerizable compound 3 of example 1, and an SA additive selected from the group consisting of formulas SA-20 to SA-34 and SA-44.

Examples

The following examples illustrate the invention without limiting it. However, it shows the person skilled in the art the concept of preferred mixtures and the compounds preferably used and their respective concentrations and combinations with each other. In addition, the embodiments illustrate the features and combinations of features that can be obtained.

In addition, the following abbreviations and symbols are used:

V₀representing the threshold voltage, capacitive [ V ], at 20 deg.C]，

n_eRepresents an extraordinary refractive index at 20 ℃ and 589nm,

n_oshowing the ordinary refractive index at 20 c and 589nm,

Δ n represents the optical anisotropy at 20 ℃ and 589nm,

_⊥represents the dielectric constant perpendicular to the director at 20 c and 1kHz,

_||represents the dielectric constant parallel to the director at 20 c and 1kHz,

Δ represents the dielectric anisotropy at 20 ℃ and 1kHz,

p. and T (N, I) represents clearing point [ ° C ],

γ₁shows the rotational viscosity [ mPas ] at 20 DEG C]，

K₁Denotes the elastic constant at 20 ℃ for "splay" deformation [ pN]，

K₂Denotes the elastic constant at 20 ℃ for "distortion" deformation [ pN]，

K₃Denotes the elastic constant at 20 ℃ for "bending" deformation pN]。

All concentrations in this application are given in weight percent and refer to the corresponding whole mixture, which contains all solid or liquid crystal components (without solvent), unless explicitly stated otherwise.

Unless otherwise indicated, all temperature values indicated in the present application, such as melting point T (C, N), transition T (S, N) from smectic phase (S) to nematic phase (N) and clearing point T (N, I) are expressed in degrees celsius (° C). M.p. denotes melting point, cl.p. ═ clearing point. Furthermore, C ═ liquid crystal phase, N ═ nematic phase, S ═ smectic phase and I ═ isotropic phase. The data between these symbols represents the transition temperature.

All physical properties are and have been determined according to "Merck Liquid Crystals, physical Properties of Liquid Crystals" Status 1997, 11 months, Merck KGaA, Germany and apply for temperatures of 20 ℃ and Δ n is determined at 589nm and Δ is determined at 1kHz, unless explicitly stated otherwise in each case.

The term "threshold voltage" as used in the present invention relates to the capacitive threshold (V)₀) It is also referred to as Freedericks threshold unless otherwise noted. In an embodiment, the optical threshold is also for a relative contrast (V) of 10% as usual₁₀) Given below.

Unless otherwise indicated, the process of polymerizing the polymerizable compounds in a PSA display as described above and below is carried out at a temperature where the LC medium exhibits a liquid crystal phase, preferably a nematic phase, and most preferably at room temperature.

Unless otherwise indicated, methods of preparing test cartridges and measuring their electro-optic and other properties are performed by the methods described below or similar methods thereto.

The display used to measure the capacitive threshold voltage consists of two plane-parallel glass outer plates spaced 25 μm apart, each having an electrode layer on the inside and an unground polyimide alignment layer on top, which results in homeotropic edge alignment of the liquid crystal molecules.

The display or test cell for measuring tilt angles for PS-VA displays consists of two plane-parallel glass outer plates with a spacing of 4 μm, each outer plate having an electrode layer on the inside and a polyimide alignment layer on top, wherein the two polyimide layers rub against each other antiparallel and cause homeotropic edge alignment of the liquid crystal molecules. The display or test cell used to measure the tilt angle of the SA-VA display is the same, but with one or no polyimide layer. A resin BM (black matrix) covers the LC discontinuous lines and the ITO slits on the two substrates.

The polymerizable compounds are polymerized in the display or test cell by irradiation with UV light of defined intensity for a predetermined time while a voltage is applied to the display (typically 10V to 30V ac or dc). In factIn the examples, unless otherwise stated, a metal halide lamp and 0.01 to 3mW/cm²The strength of (2) is used for polymerization. The intensity was measured using a standard meter (UV-meter with UV sensor, ORC).

The tilt angle was determined using a Mueller Matrix Polarimeter "AxoSacn" from Axmetrics. Here a low value, i.e. a large deviation from a 90 deg. angle, corresponds to a large pretilt.

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 optically major axis of the LC molecules in a layer of LC molecules with uniform orientation, corresponding to their molecular long axis in the case of rod-shaped, uniaxial, positively birefringent LC molecules.

Examples

Examples of mixtures

H1 nematic host mixture (Delta <0)

H2 nematic host mixture (Delta <0)

H3 nematic host mixture (Δ >0)

H4 nematic host mixture (Δ >0)

H5 nematic host mixture (Δ >0)

Mixture example A

The polymerisable mixture was prepared by adding 0.3% of reactive mesogen RM-1 and 0.6% of SA additive SA-23 to nematic LC host mixture H1.

Mixture example B

The polymerisable mixture was prepared by adding 0.3% of reactive mesogen RM-1, 0.5% of SA additive SA-23 and 0.2% of SA additive SA-35 to nematic LC host mixture H1.

Evaluation in test cartridges

Each polymerizable mixture was filled into a test cell. The polymerizable compound was photopolymerized by UV exposure for 100s (UV1-a) with a voltage application of 0V, followed by UV exposure for another 100s (UV1-b) with a voltage application of 20V DC.

The second step UV1-b results in the creation of a tilt angle. After final curing (UV2), several properties were measured, such as VHR before and after UV stress, generation of tilt angle and residual RM content.

UV1-a/UV1-b:At 0.4mW/cm²Lower UV irradiation (measured using an ORC313nm sensor). The lamp type: toshiba lamps, metal halide lamps; the temperature was 25 ℃.

Applied electrode voltage

UV1-a:0V，100s

UV1-b:20V DC，100s。

UV2:Type C fluorescent UV lamp, room temperature, 120 min.

Comparative example the following irradiation was carried out:

UV1:20V DC，100s，

UV2:type C fluorescent UV lamp, room temperature, 120 min.

The two-step polymerization process is highly suitable for polymer stabilized SA-VA displays.

Drip non-uniformity evaluation

The test cartridge was filled by the drop fill (ODF) method. The substrate with the fishbone electrode structure and VA-polyimide coating was provided with a dot of about 0.3mg of LC mixture and sealed under vacuum with a flat (plain) ITO coated substrate. After completion of the two-step UV1 process and UV2 final cure, the areas were examined for dark and light areas at the same mean gray value (2.2-2.6V). The non-uniformity level is calculated from the maximum difference in brightness between the dripping area and the non-dripping area.

As a result:

the two-step process had an acceptable level of non-uniformity by visual inspection. The display according to the conventional method has visible dripping non-uniformity. The initial drip area is darker than the surrounding area. It is surmised that higher amounts of SA additive in the center region result in stronger homeotropic orientation and lower pretilt angle. The drop non-uniformity levels calculated by gray scale analysis are provided in table 1.

TABLE 1 level of dripping non-uniformity

Mixture of	Method of producing a composite material	Drop non-uniformity
			Mixture example A	Two step UV1	22％
Mixture example A	One step UV1	48％
			Mixture example B	Two step UV1	25％
Mixture example B	One step UV1	40％

VHR evaluation

After the complete UV1 and UV2 methods, the VHR (voltage holding ratio) of the polymerizable LC medium was measured at 60 ℃ and with a voltage of 1V/0.6 Hz. The results are shown in Table 2.

TABLE 2 Voltage Holding Ratio (VHR)

Mixture of	Method of producing a composite material	VHR (%) initial
			Mixture example A	Two step UV1	97.4
Mixture example A	One step UV1	97.9
			Mixture example B	Two step UV1	97.2
Mixture example B	One step UV1	98.1

The voltage holding ratio is hardly changed between the one-step and two-step UV method modes.

Tilt angle assessment

By using a 320nm long pass filter and 0.4mW/cm²Is irradiated under a metal halide lamp for UV photopolymerization (ORC313nm detector). In the measurement and use of Axometrics

The test cell was given a rest of at least 12 hours before calculating the final tilt angle. The results are shown in Table 3.

TABLE 3 Tilt Angle

Mixture of	Method of producing a composite material	Pre-tilt	Angle of inclination
				Mixture example A	Two step UV1	0.8°	89.2°
Mixture example A	One step UV1	1.2°	88.8°
				Mixture example B	Two step UV1	1.1°	88.9°
Mixture example B	One step UV1	1.4°	88.6°

It can be seen that the tilt angle produced in the mixture is lower for the two-step process. This is advantageous in the case of SA-PSA displays, which tend to produce high pretilt angles very quickly. The two-step process provides more time and allows the tilt angle to be adjusted within the desired range with greater accuracy.

The stability of the tilt angle was tested on a PI-free (PI-less) test box. The tilt angle stability varies with each self-aligning additive. It may be higher or lower than the one-step process. Careful selection of additives can lead to improved tilt stability.

Claims (18)

1. A method of manufacturing an LC display,

   wherein the LC display comprises a pair of substrates provided with electrodes on one or both substrates, and a layer of LC medium between the substrates,

   wherein the method comprises the following steps:

   -providing an LC medium between the substrates of the LC display,

   the LC medium initially comprises

   A polymerizable component A) consisting of one or more polymerizable compounds,

   a liquid-crystalline component B) comprising one or more mesogenic or liquid-crystalline compounds,

   in a first UV method step, the polymerisable component A) of the LC medium is polymerised without applying an electrical potential to the electrodes, and then

   In a second UV method step, the polymerisable component a) of the LC medium is polymerised in the presence of an electric potential or field applied to the electrodes, wherein the LC medium adopts a pre-tilt.
2. 2. The method according to claim 1, wherein the third polymerization step is performed after the first and second UV polymerization steps of the LC medium without applying a potential to the electrodes.
3. 3. The method according to claim 1 or 2, wherein the first UV method step of the LC medium is carried out for 10 to 200 s.
4. 4. The method according to one or more of claims 1 to 3, wherein the first UV polymerization step of the LC medium is carried out for 20 to 150 s.
5. 5. The method according to one or more of claims 1 to 4, wherein the second UV method step of the LC medium is carried out for 10 to 200 s.
6. 6. The method according to one or more of claims 1 to 5, wherein a first UV method step of the LC medium is terminated and replaced by the second UV method step before the first UV step completely polymerizes the LC medium.
7. 7. The method according to one or more of claims 1 to 6, wherein the LC medium comprises

   Polymerizable component A) comprising, preferably consisting of, one or more polymerizable compounds, at least one of which is a compound of the formula I,

   P-Sp-A¹-(Z¹-A²)_z-R^bI

   wherein the radicals, independently of one another and identically or differently at each occurrence, have the following meanings

   R^bIs P-Sp-or R,

   r is F, Cl, -CN or a linear, branched or cyclic alkyl radical having 1 to 25C atoms, one or more non-adjacent CH₂-the group is optionally replaced by-O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O-in such a way that the O-and/or S-atoms are not directly connected to each other, and wherein one or more H atoms are each optionally replaced by F or Cl,

   p is a polymerizable group, and P is a polymerizable group,

   sp is a spacer group optionally substituted with P, or a single bond,

   A¹、A²is a monocyclic or polycyclic aromatic or heteroaromatic group having 4 to 20 ring atoms, which is optionally substituted by one or more groups L or P-Sp-,

   Z¹is-O-, -S-, -CO-O-, -O-CO-O-, -OCH₂-，-CH₂O-，-SCH₂-，-CH₂S-，-CF₂O-，-OCF₂-，-CF₂S-，-SCF₂-，-(CH₂)_n1-,-CF₂CH₂-，-CH₂CF₂-，-(CF₂)_n1-，-CH＝CH-，-CF＝CF-，-CH＝CF-，-CF＝CH-，-C≡C-，-CH＝CH-CO-O-，-O-CO-，-CH＝CH-，-CH₂-CH₂-CO-O-，-O-CO-CH₂-CH₂-，-CR⁰R⁰⁰-or a single bond,

   R⁰，R⁰⁰is H or alkyl having 1 to 12C atoms,

   l is F, Cl, -CN, P-Sp-, or a linear, branched or cyclic alkyl or alkenyl group having 1 to 25C atoms, wherein one or more non-adjacent CH₂-the group is optionally replaced by-O-, -S-, -CO-O-, -O-CO-O-in such a way that the O-atoms and/or the S-atoms are not directly attached to each other, and wherein one or more H atoms are each optionally replaced by P-Sp-, F or Cl,

   z is 0,1,2 or 3,

   and

   n1 is 1,2,3 or 4.
8. 8. The method according to one or more of claims 1 to 7, wherein the LC medium comprises

   -one or more additives selected from self-aligning additives for homeotropic alignment of formula II

   MES-R^aII

   Wherein

   MES is a rod-like mesogenic group comprising two or more rings which are directly or indirectly connected to each other or which are fused to each other, which are optionally substituted and whose mesogenic group is optionally additionally substituted by one or more polymerizable groups which are connected to MES directly or via a spacer, and

   R^ais a polar anchor group, located in a terminal position of the rod-like mesogenic group MES, comprising at least one carbon atom and at least one group selected from: -OH, -SH, -COOH, -CHO or a primary or secondary amine function or a group having three or more O atoms, preferably a group having one or two OH groups, and which optionally contains one or two polymerizable groups P.
9. 9. The method according to one or more of claims 1 to 8, wherein the LC medium comprises

   -a polymerizable component A comprising at least one compound of formula I and at least one polymerizable self-alignment additive for homeotropic alignment of formula II),

   a liquid-crystalline component B) comprising, preferably consisting of, one or more mesogenic or liquid-crystalline compounds,

   P-Sp-A¹-(Z¹-A²)_z-R^bI

   MES-R^aII

   wherein the radicals, independently of one another and identically or differently at each occurrence, have the following meanings

   R^bIs P-Sp-or R,

   r is F, Cl, -CN or a linear, branched or cyclic alkyl radical having 1 to 25C atoms, one or more non-adjacent CH₂-the group is optionally replaced by-O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O-in such a way that the O-and/or S-atoms are not directly connected to each other, and wherein one or more H atoms are each optionally replaced by F or Cl,

   p is a polymerizable group, and P is a polymerizable group,

   sp is a spacer group optionally substituted with P, or a single bond,

   A¹，A²is a monocyclic or polycyclic aromatic or heteroaromatic group having 4 to 20 ring atoms, which is optionally substituted by one or more groups L or P-Sp-.

   Z¹is-O-, -S-, -CO-O-, -O-CO-O-, -OCH₂-，-CH₂O-，-SCH₂-，-CH₂S-，-CF₂O-，-OCF₂-，-CF₂S-，-SCF₂-，-(CH₂)_n1-,-CF₂CH₂-，-CH₂CF₂-，-(CF₂)_n1-，-CH＝CH-，-CF＝CF-，-CH＝CF-，-CF＝CH-，-C≡C-，-CH＝CH-CO-O-，-O-CO-，-CH＝CH-，-CH₂-CH₂-CO-O-，-O-CO-CH₂-CH₂-，-CR⁰R⁰⁰-or a single bond,

   R⁰，R⁰⁰is H or alkyl having 1 to 12C atoms,

   l is F, Cl, -CN, P-Sp-or a linear, branched or cyclic alkyl or alkenyl group having 1 to 25C atoms, in which one or more non-adjacent CH groups₂-the group is optionally replaced by-O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O-in such a way that the O-and/or S-atoms are not directly connected to each other, and wherein one or more H atoms are each optionally replaced by P-Sp-, F or Cl,

   z is 0,1,2 or 3,

   n1 is 1,2,3 or 4,

   MES is a rod-like mesogenic group comprising two or more rings which are directly or indirectly connected to each other or which are fused to each other, which are optionally substituted and whose mesogenic group is additionally substituted by one or more polymerizable groups which are connected to MES directly or via a spacer, and

   R^ais a polar anchor group, located in a terminal position of the rod-like mesogenic group MES, comprising at least one carbon atom and at least one group selected from: -OH, -SH, -COOH, -CHO or a primary or secondary amine function, preferably one or two OH groups, and which optionally contains one or two polymerizable groups P.
10. 10. Method according to any one of claims 1 to 9, characterized in that the compound of formula I is selected from the following subformulae:

    

    

    

    

    L¹¹,L¹²,L¹³independently as L in claim 9,

    r1, r2, r3 are 0,1,2, 3 or 4,

    r4, r5 is 0,1,2 or 3,

    and

    p is a polymerizable group, and

    sp is a spacer group optionally substituted with P, or a single bond.
11. 11. Process according to any one of claims 1 to 10, characterized in that the group P in the compounds of formulae I and II is selected from vinyloxy, acrylate, methacrylate, fluoroacrylate, chloroacrylate, oxetane and epoxy.
12. 12. The process according to any one of claims 1 to 11, characterized in that the self-aligning additive for homeotropic alignment comprises one or more polymerizable groups P-Sp-.
13. 13. Process according to any one of claims 1 to 12, characterized in that the self-aligning additive for homeotropic alignment is selected from the following formulae

    

    Wherein

    A²²Each independently of the others, represents an aromatic, heteroaromatic, alicyclic or heterocyclic group, which may also contain fused rings, and which may also be interrupted by a group L¹²or-Sp-P mono-or polysubstituted,

    L¹²in each case independently of one another F, Cl, Br, I, -CN, -NO₂，-NCO，-NCS，-OCN，-SCN，-C(＝O)N(R⁰)₂，-C(＝O)R⁰Optionally substituted silyl, optionally substituted aryl or cycloalkyl having 3 to 20C atoms, or straight-chain or branched alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy having up to 25C atoms, where, in addition, one or more H atoms may each be replaced by F or Cl,

    p represents a polymerizable group, and P represents a polymerizable group,

    sp represents a spacer group or a single bond,

    Z²²in each case independently of one another, represents a single bond, -O-, -S-, -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-，-(CR⁰R⁰⁰)_n1-，-CH(-Sp-P)-，-CH₂CH (-Sp-P) -, or-CH (-Sp-P) CH (-Sp-P) -,

    n1 represents a number of atoms of 1,2,3 or 4,

    m2 represents 1,2,3,4, 5 or 6,

    R⁰in each case independently of one another denote alkyl having 1 to 12C atoms,

    R⁰⁰in each case independently of one another, H or alkyl having 1 to 12C atoms,

    R²¹independently of one another, H, halogen, straight-chain, branched or cyclic alkyl having 1 to 25C atoms, where, in addition, one or more non-adjacent CH₂The radicals may each be replaced by-O-, -S-, -CO-O-, -O-CO-, or-O-CO-O-in such a way that the O and/or S atoms are not linked directly to one another and wherein, in addition, one or more H atoms may each be replaced by F or Cl,

    or a group P-Sp-, and

    R^ais a polar anchoring group according to claim 9, preferably a polar anchoring group further defined by: having at least one group selected from: -OH, -NH₂，NHR²²C (O) OH and-CHO or a group having three or more O atoms, wherein

    R²²Represents an alkyl group having 1 to 12C atoms, and

    r1 is independently 0,1,2, 3, or 4.
14. 14. The process according to any one of claims 1 to 13, characterized in that in the formulae II, IIa and II-A to II-B, the polar anchoring groups R^aSelected from the following formulae

    

    Wherein

    p is 1,2,3,4, 5 or 6,

    x is 1 or 0, preferably 1, and

    R²³is H, methyl, ethyl, n-propylIsopropyl group, n-butyl group, tert-butyl group, n-pentyl group, or-CH₂CH₂-tert-butyl.
15. 15. Method according to any one of claims 1 to 14, characterized in that the LC medium comprises one or more compounds of formula CY and/or PY:

    

    wherein the individual radicals have the following meanings:

    a represents a number of 1 or 2,

    b represents a number of 0 or 1,

    

    to represent

    

    R¹And R²Each independently of the other represents an alkyl radical having 1 to 12C atoms, where, in addition, one or two non-adjacent CH groups₂The radicals may be replaced by-O-, -CH-, -CO-, -O-CO-or-CO-O-in such a way that the O atoms are not directly linked to one another,

    Z^xdenotes-CH-, -CH ═ CH-, -CH₂O-，-OCH₂-，-CF₂O-，-OCF₂-，-O-，-CH₂-，-CH₂CH₂-or a single bond, preferably a single bond,

    L^1-4each independently of the others represents F, Cl, OCF₃，CF₃，CH₃，CH₂F，CHF₂。
16. 16. The method according to any one of claims 1 to 15, characterized in that said LC medium comprises one or more compounds selected from the group consisting of the following formulae:

    

    wherein the individual radicals, which are identical or different at each occurrence, each independently of one another, have the following meanings:

    

    is composed of

    

    

    

    Is composed of

    

    

    

    Is composed of

    

    

    R^A1Is alkenyl having 2 to 9C atoms, or R if at least one of rings X, Y and Z represents cyclohexenyl^A1And also has R^A2In one of the meaning of (a),

    R^A2is alkyl having 1 to 12C atoms, wherein furthermore one or two non-adjacent CH' s₂The radicals may be replaced by-O-, -CH-, -CO-, -OCO-or-COO-in such a way that O atoms are not bonded directly to one another,

    Z^xis-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,

    L^1-4each independently of the others being H, F, Cl, OCF₃，CF₃，CH₃，CH₂F or CHF₂H, preferably H, F or Cl,

    x is 1 or 2, and the compound is,

    z is 0 or 1.
17. 17. The method according to any one of claims 1 to 16, characterized in that said LC medium comprises one or more compounds of formula:

    

    wherein the individual radicals have the following meanings:

    

    to represent

    

    

    

    To represent

    

    R³And R⁴Each independently of the other represents an alkyl radical having 1 to 12C atoms, where, in addition, one or two non-adjacent CH groups₂The radical may be substituted by-O-, -CH- ═ CH-, -CO-, -O-CO-or-CO-is replaced in such a way that the O atoms are not directly linked to each other,

    Z^yrepresents-CH₂CH₂-，-CH＝CH-，-CF₂O-，-OCF₂-，-CH₂O-，-OCH₂-，-COO-，-OCO-，-C₂F₄-, -CF ═ CF-or a single bond.
18. 18. An LC display manufactured according to any of claims 1 to 17.