LCD display

Abstract

Provides a liquid crystal display. The present invention relates to a chiral polymer stabilized alignment (C-PSA) mode liquid crystal display (LCD), its manufacturing method and its use as an energy-saving display.

Description

[Technical field]

[0001] The present invention relates to a chiral polymer stabilized alignment (C-PSA) mode liquid crystal display (LCD), its manufacturing method and its use as an energy saving display. [Background technology]

[0002] Many LCD panels used, for example in monitors or LCD TVs, use polymer stabilized (PS) or polymer sustained alignment (PSA) modes such as PS-VA (vertically aligned), PS-IPS (in-plane switching) or PS-FFS (fringe-field switching) modes or modes derived therefrom, or self-aligned (SA) modes such as polymer stabilized SA-VA.

[0003] In the PS or PSA mode, a small amount, typically 0.1-1%, of one or more polymerizable mesogenic compounds, also known as RMs (reactive mesogens), is added to the LC medium. After the LC medium is filled into the display, the RMs are polymerized in situ by UV photopolymerization while applying a voltage to the electrodes of the display. This creates a specific tilt angle in the LC molecules of the LC medium, mainly in the area close to the surface of the display cell, and the display cell is stabilized by the polymerized RMs. The UV polymerization process, also called the "PSA process", is usually performed in two steps, a first UV exposure step ("UV1 step") to create the tilt angle by applying a voltage, and a second UV exposure step ("UV2 step") to complete the polymerization of the RMs without applying a voltage.

[0004] In the SA-VA mode, the alignment layer in the display is omitted. Instead, a small amount, typically 0.1-2.5%, of a self alignment (SA) additive is added to the LC medium, which induces the desired alignment, e.g., homeotropic or planar alignment, in situ by a self-assembly mechanism. The SA additive usually contains an organic mesogenic core group to which one or more polar anchor groups, e.g., hydroxy, carboxy, amino or thiol groups, are attached, which can interact with the substrate surface to align the additive on the substrate surface and also induce the desired alignment in the LC molecules. The SA additive may also contain one or more polymerizable groups that can be polymerized under similar conditions as the RM used in the PSA process. In addition to the SA additive, the LC medium may also contain one or more RMs.

[0005] The PSA displays used for the monitors are usually of the active matrix (AM) type. AM-LCDs are known in the prior art. The nonlinear elements that allow the individual pixels to be switched individually are active elements such as transistors, in particular thin-film transistors (TFTs) on a glass plate as substrate. These can be chosen from TFTs containing compound semiconductors such as CdSe, or metal oxide TFTs such as IGZO (indium gallium indium zinc oxide), or TFTs based on polycrystalline or amorphous silicon. In particular the latter technology is being intensively investigated worldwide.

[0006] The TFT matrix is ​​attached to the inside of one glass plate of the display, while the other glass plate carries a transparent counter electrode on its inside. Compared to the size of the pixelated electrodes, the TFTs are so small that they have virtually no adverse effect on the image. The technology can also be extended to full-color displays, where a mosaic of red, green and blue filters is arranged so that a filter element faces each switchable pixel.

[0007] In this specification, the term MLC display covers all matrix displays in which non-linear elements are integrated, i.e. also displays which, besides the active matrix, comprise passive elements such as varistors or diodes (MIM: metal-insulator-metal).

[0008] MLC displays of this type are particularly suitable for television applications (eg portable televisions) or for high information displays in automotive or aerospace structures.

[0009] In many MLC-type PSA displays, one of the two electrodes sandwiching the layer of LC medium has a pixelated structure, such as a fishbone pattern with a central cross-shaped structure as illustrated in FIG. 1(a). In the addressed state (i.e., when a voltage is applied to the electrodes), the LC molecules change from their initial vertical or tilted orientation to a planar orientation, but in addition, the long axis of the LC molecules is oriented in a direction mainly induced by the electric field provided by the electrode pattern. However, it has been observed that the transmittance is still not sufficient in these displays. In particular, the appearance of dark trunk lines within individual pixels and dark edge lines between adjacent pixels has been observed, as shown in FIG. 2(a). This can be attributed to two aspects. One is that the LC orientation in the trunk region is parallel to the trunk and also parallel or perpendicular to the polarizer, where the dark trunk lines arise. The other is the insufficient orientation of the LC molecules due to the non-uniform electric field generated by the patterned electrodes and also by the gap between the pixelated electrodes.

[0010] The dark trunk lines can be partially overcome by adding a chiral dopant to the LC medium. This type of PSA (or PSVA) display mode, which comprises an LC medium with a chiral dopant, is also known as C-PSA or C-PSVA mode.

[0011] The chiral dopant induces a helical twist in the planar aligned LC molecules in the addressed state, so that at least some of the LC molecules have the desired alignment direction in the areas covering the pixelated electrodes. As a result, the occurrence of dark trunk lines is suppressed and the overall transmittance is improved, as shown in Figure 2(b). However, dark edge lines are still visible in the gap regions between pixels due to the non-uniform electric field near the edge regions. Summary of the Invention [Problem to be solved by the invention]

[0012] It is therefore an object of the present invention to provide a novel display in C-PSA mode exhibiting improved transparency. In addition, the display should exhibit advantageous properties such as low driving voltage and good contrast ratio. Another object of the present invention is to provide a method for producing such a PSA display. Other objects of the present invention will be readily apparent to those skilled in the art from the following description. [Means for solving the problem]

[0013] It has been found that these objects can be achieved by providing a PSA mode display as disclosed and claimed hereinafter. In particular, it has been surprisingly found that by adding a third electrode layer to the display on the side of the patterned second electrode, but where the second and third electrodes are separated by an insulating layer, it is possible to suppress the appearance of both the dark trunk lines and the dark edge lines as shown in FIG. 2(c). In addition, the third electrode not only improves the dark trunk and edge lines, but also improves the overall transmission of the whole pixel, since it provides a uniform and linear electric field that can improve the alignment of the twisted LC molecules compared to the electric field of the patterned electrode. Thus, a higher transmission can be achieved. This also allows energy savings, for example by reducing the backlight power.

[0014] <Summary of the Invention> The present invention relates to a liquid crystal display (LCD) in a chiral polymer-stabilized alignment (C-PSA) mode, preferably in a chiral polymer stabilized vertical aligned (C-PSVA) mode, comprising: a) a first substrate comprising a first electrode and optionally a first alignment layer, said first electrode optionally having a particular pattern and optionally divided into a number of pixels; b) a layer comprising a nematic LC medium having negative dielectric anisotropy, comprising a chiral additive and further comprising a polymer formed by one or more polymerizable compounds, c) a second substrate comprising a second electrode and optionally a second alignment layer, said second electrode having a pattern, preferably a fishbone pattern, and preferably divided into a plurality of pixels; d) optionally including a color filter, preferably disposed adjacent the second electrode; provided that the optional first and second alignment layers, if present, are arranged in contact with the LC medium; The second substrate further comprises a third electrode and an electrically insulating layer between the second and third electrodes, the third electrode may have a pattern and may be divided into a plurality of pixels; with the proviso that the display further comprises a non-linear element, preferably selected from an active element, more preferably a transistor, very preferably a thin-film transistor (TFT), for electronically addressing individual pixels, said non-linear element being in contact with the second electrode and / or the third electrode or in contact with the first electrode; and wherein said one or more polymerizable compounds in the LC medium are polymerized in situ after the LC medium is dispensed between the two substrates while applying a voltage to at least the first and second electrodes, and preferably also to the third electrode.

[0015] The present invention further relates to a method for producing a C-PSA mode, preferably a C-PSVA mode, LC display, comprising the steps of: a) providing a first substrate and a second substrate, the first substrate being provided with a first electrode and optionally a first alignment layer, and the second substrate being provided with a second electrode, optionally a second alignment layer, a third electrode, an electrical insulating layer between the second and third electrodes and optionally a color filter; However, the first and / or second substrate are preferably provided with fixing means, preferably a sealant material and / or a spacer, for fixing the first and second substrates at a certain distance from each other and with their planes parallel to each other, with the proviso that the second electrode has a pattern, preferably a fishbone pattern, and is preferably divided into a plurality of pixels, and the first and / or third electrode optionally have a pattern, and optionally are divided into a plurality of pixels; with the proviso that the display further comprises a non-linear element, preferably selected from an active element, more preferably a transistor, very preferably a thin film transistor (TFT), for electronically addressing individual pixels, said non-linear element either in contact with the second and / or third electrode or in contact with the first electrode; b) distributing a nematic LC medium between first and second substrates such that the LC medium is in contact with the first and second alignment layers, if these are present, However, the LC medium has a negative dielectric anisotropy, A) a liquid crystal component A comprising, and preferably consisting of, mesogenic or liquid crystal molecules (hereinafter also referred to as "LC host mixture"); B) a polymerizable component B comprising, and preferably consisting of, one or more polymerizable compounds; C) one or more chiral additives, preferably selected from chiral dopants; D) optionally and preferably comprising one or more further additives selected from polymerization initiators, stabilizers and self-aligning additives, c) applying a voltage to the first and second electrodes and preferably also to the third electrode; d) polymerizing the polymerizable compounds of the polymerizable component B of the LC medium between the first and second substrates, preferably by exposure to UV radiation while applying a voltage; e) optionally subjecting the LC medium to a second polymerization step without applying a voltage to the first, second or third electrodes, preferably by exposure to UV radiation, thereby polymerizing all polymerizable compounds that did not react in step d).

[0016] The present invention further relates to the use of a C-PSA or C-PSVA mode LC display according to the invention as an energy saving display. [Brief description of the drawings]

[0017] [Figure 1] 1(a)-(e) show suitable and preferred electrode patterns in a C-PSA display according to the present invention.

[0018] [Diagram 2] 2(a)-(c) show microscopic images of a prior art PSA display (a), a prior art C-PSA display (b) and a C-PSA display according to the present invention (c) in the addressed state.

[0019] [Diagram 3] FIG. 3 shows the electrode configuration in a prior art PSA display.

[0020] [Figure 4] 4(a)-(d) show preferred electrode configurations in a C-PSA display according to the present invention.

[0021] [Diagram 5] FIG. 5 shows the gap areas between individual pixels in a C-PSA display according to the present invention.

[0022] [Figure 6]6(a)-(d) show the PSA process in a prior art PSA display.

[0023] [Figure 7] 7(a)-(e) show the PSA process in a C-PSA display according to the present invention.

[0024] [Figure 8] FIG. 8 shows the transmittance of C-PSA displays according to Comparative Example 1 (graph a) and Example 1 (graph b) of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] <Terms and definitions> As used herein, the terms "tilt" and "tilt angle" are understood to refer to the orientation in which the long axes of the LC molecules of the LC medium form an angle with the plane of the nearest substrate of the display cell.

[0026] As used herein, the term "director" or "LC director" is understood to mean the average direction of the long molecular axes of the LC molecules.

[0027] As used herein, the terms "polymerizable mesogenic compound", "reactive mesogen" and "reactive mesogen" are understood to mean a compound containing a mesogenic or liquid crystalline backbone and one or more functional groups attached to the backbone suitable for polymerization, which functional groups are also referred to as "polymerizable groups" or "P".

[0028] As used herein, unless otherwise stated, the term "polymerizable compound" is understood to mean a polymerizable monomeric compound.

[0029] References above and below to an LC medium comprising "a polymer formed / obtained by polymerizing one or more polymerizable compound(s) / component(s)" should be understood to encompass both embodiments in which the polymer remains partially or is fully dispersed in the LC medium, as well as embodiments in which the polymer precipitates from the LC medium and forms a polymer layer on one or both of the substrates or on one or both of the alignment layers or on an electrode structure deposited thereon.

[0030] As used herein, the term "low molecular weight compound" is understood as a term in contrast to "polymeric compound" or "polymer" to mean a compound that is monomeric and / or not prepared by a polymerization reaction.

[0031] As used herein, the term "non-polymerizable compound" is understood to mean a compound that does not contain any functional group suitable for polymerization under the conditions normally applied for the polymerization of RMs.

[0032] As used herein, the term "mesogenic group" refers to a group known to those skilled in the art and described in the literature, which essentially contributes to the generation of a liquid-crystalline (LC) phase in low molecular weight or polymeric substances due to the anisotropy of its attractive and repulsive interactions. A compound containing a mesogenic group (mesogenic compound) does not necessarily have an LC phase by itself. It is also possible that a mesogenic compound exhibits LC phase behavior only after mixing with other compounds and / or after polymerization. Typical mesogenic groups are, for example, rigid rod-like or disc-like shaped units. A review of the terms and definitions used in relation to mesogens or LC compounds is given in Pure Appl.Chem. 2001, Vol. 73 (No. 5), p. 888 and C. Tschierske, G. Pelzl, S. Diele, Angew.Chem. 2004, Vol. 116, p. 6340-6368.

[0033] As used herein, the term "spacer group", hereafter also referred to as "Sp", is known to those skilled in the art and described in the literature, see for example Pure Appl.Chem. 2001, vol. 73 (no. 5), p. 888 and C. Tschierske, G. Pelzl, S. Diele, Angew.Chem. 2004, vol. 116, p. 6340-6368. As used herein, the term "spacer group" or "spacer" refers to a flexible group, such as an alkylene group, that links the mesogenic group and the polymerizable group(s) in a polymerizable mesogenic compound.

[0034] <Detailed Description of the Invention> The LC display according to the present invention is preferably a C-PSVA display. Thus, as described hereinafter, the preferred embodiments of the display according to the present invention (having an electrode structure comprising a third electrode and a polymerizable LC medium comprising a chiral dopant) preferably relate to displays in C-PSVA mode. However, they may also be applied or used for other polymer stabilized (PS, polymer stabilized) display modes such as PS-IPS mode, PS-FFS mode or polymer stabilized SA-VA mode. The necessary modifications to adapt the preferred embodiments for these other PS modes can be made by a person skilled in the art based on his general knowledge.

[0035] The structure of the display according to the invention corresponds to the usual configurations for PSA displays as described in the prior art: Configurations without protrusions are preferred, especially those in which the color filters and the electrodes on the TFT side are structured.

[0036] Figure 3 exemplarily and diagrammatically illustrates the electrode configuration of a PSA display according to the prior art. The curved arrow indicates the line of sight. From top to bottom, the display comprises a first or upper substrate (301), a second or lower substrate (302), a first or upper continuous electrode (303) provided on the first substrate (301) and a second or lower electrode (304) with a fishbone pattern provided on the second substrate (302).

[0037] In Fig. 3, three pixels of a PSA display are exemplarily shown with gaps between the patterned electrode substructures of each pixel, as indicated by the double arrows. The PSA display further comprises an alignment layer on the first and second electrodes, an RGB color filter with each R, G and B region corresponding to one pixel, and a non-linear element or addressing means, preferably a TFT, arranged at the bottom and connected to the second or bottom electrode (304) via electrical contacts, for electronically addressing the individual pixels. The non-linear elements are interconnected such that the pixels can be individually addressed in an active matrix driving (AMD) manner. And the display further comprises an insulating layer (305) to separate the second electrode from the TFT.

[0038] The layer of LC medium with polymerisable or polymerised compounds is placed between the first and second electrodes in contact with the first and second alignment layers, if present.

[0039] Due to the non-uniform electric field generated by the patterned electrodes as discussed above, the LC molecules may exhibit poor rotation and orientation in the areas overlying the patterned electrodes when a voltage is applied to the electrodes during operation of the display.

[0040] Furthermore, due to the pixelated structure of the second electrode as shown in Figure 3, the layer of LC medium will contain LC molecules in areas covering the pixelated electrodes and in areas covering the gaps between the pixelated electrodes. Thus, when a voltage is applied to the electrodes during operation of the display, the LC molecules in the areas covering the gaps will not experience the same orientation force of the electric field as the LC molecules in the areas covering the pixelated electrodes. This may lead to insufficient orientation and rotation of the LC molecules in the gap areas.

[0041] For the reasons given above, the transmittance of the display in the addressed state (ie having a voltage applied to the electrodes) may be reduced.

[0042] Applying an additional third electrode underneath the patterned second electrode in a display according to the present invention can solve this problem.

[0043] FIG. 4 exemplarily and diagrammatically illustrates the electrode configurations in the C-PSA display in the first (a), second (b), third (c) and fourth (d) preferred embodiments of the present invention. The curved arrow indicates the line of sight. The display includes a first substrate (401), a first electrode (403) provided on the first substrate (401), a second substrate (402), a second ITO electrode (404) having a fishbone pattern and an insulating layer (405) provided on the second substrate (402), and a third ITO electrode (406) provided between the second substrate (402) and the insulating layer (405).

[0044] 4(a)-(d) each show three exemplary pixels of a C-PSA display with gaps between the patterned electrode substructures of each pixel as indicated by double arrows. The C-PSA display further comprises an alignment layer on the first and second electrodes, an RGB color filter with each R, G and B region corresponding to one pixel, and a nonlinear element or addressing means disposed underneath and connected to the second electrode (404) and the third electrode (406) via electrical contacts, preferably a TFT, very preferably a TFT based on polycrystalline or amorphous silicon including CdSe, or an oxide TFT such as IGZO, not shown. The display preferably further comprises a second insulating layer (407), for example of SiNx, to separate the second and third electrodes from the TFT.

[0045] A layer of an LC medium with a polymerisable or polymerised compound is arranged between the first and second electrodes in contact with the first and second alignment layers, if present.

[0046] Similar to the prior art display shown in Figure 3, in the C-PSA display of the present invention as shown in Figures 4(a)-(d) the layer of LC medium will comprise LC molecules in the areas covering the pixelated electrodes and LC molecules in the areas covering the gaps between the pixelated electrodes.

[0047] However, in a C-PSA display of the present invention, when a voltage is applied to the electrodes during operation of the display, the LC molecules both in the areas covering the pixelated electrodes and in the areas covering the gaps between the pixelated electrodes are subjected to an additional linear electric field force of a third electrode.

[0048] This is shown diagrammatically in Figure 5, which shows a detailed enlarged view of a pixel of the display shown in Figure 5, encompassing the first or top electrode (503), the second or bottom patterned electrode (504), the insulating layer (505), the third electrode (506) and the RGB colour filter (507). The dotted lines indicate the region of LC molecules covering the gap between the pixel second electrodes (504), which are subject to the additional electric field force of the third electrode (506). This results in better alignment of the LC molecules throughout the pixel and therefore improved transmittance in the addressed state.

[0049] In addition, in the PSA process that is part of the display manufacturing process, a pretilt angle is created in the LC molecules close to the substrate by polymerizing the polymerizable component in the LC medium under application of a voltage, and the electric field generated by a patterned second electrode causes the tilted LC molecules to orient at an azimuthal angle in the plane of the substrate defined by the fishbone pattern of the electrodes, also known as multi-domain alignment. As a result, during operation of the display in the addressed (i.e., driven or field-on) state, the LC molecules throughout the LC layer are predominantly oriented in the horizontal direction, which corresponds to the azimuthal angle of the pretilted LC molecules close to the substrate in the unaddressed (i.e., undriven or field-off) state.

[0050] As shown below, the third electrode can enhance the uniformity of the azimuthal alignment of the LC molecules during the PSA process, both in the areas covering the patterned electrodes and in the areas covering the gaps between the pixelated electrode structures, which contributes to a more uniform alignment of the LC molecules in the addressed state and an overall improvement in the transmittance.

[0051] In the C-PSA display according to the first preferred embodiment as shown in Fig. 4(a), the first substrate (401) is the top substrate (i.e. facing the viewer), the first electrode (403) is the top electrode, while the second substrate (402) is the bottom substrate (i.e. facing away from the viewer), the second electrode (404) and the third electrode (406) are bottom electrodes, both connected to non-linear elements such as TFTs, and the third electrode (406) preferably has a pixelated structure corresponding to the individual pixels, while the first electrode (403) is an unpatterned (i.e. continuous) electrode.

[0052] In the C-PSA display according to the second preferred embodiment as shown in Figure 4(b), the first substrate (401) is the top substrate, and the first electrode (403) is the top electrode, while the second substrate (402) is the bottom substrate, and the second electrode (404) and the third electrode (406) are the bottom electrodes, both of which are connected to non-linear elements such as TFTs, and both of the first electrode (403) and the third electrode (406) are unpatterned (i.e. continuous) electrodes.

[0053] In the C-PSA display according to the third preferred embodiment as shown in Fig. 4(c), the second substrate (402) is the top substrate and the second electrode (404) and the third electrode (406) are the top electrodes, while the first substrate (401) is the bottom substrate and the first electrode (403) is the bottom electrode, which is connected to a non-linear element such as a TFT, and the first electrode (403) preferably has a pixelated structure corresponding to the individual pixels, while the third electrode (406) is an unpatterned (i.e. continuous) electrode.

[0054] In the C-PSA display according to the fourth preferred embodiment as shown in Fig. 4(d), the second substrate (402) is the top substrate, and the second electrode (404) and the third electrode (406) are the top electrodes, while the first substrate (401) is the bottom substrate, and the first electrode (403) is the bottom electrode, which is connected to a non-linear element such as a TFT, and both the first electrode (403) and the third electrode (406) are unpatterned (i.e. continuous) electrodes.

[0055] The first (403), second (404) and third electrodes (406) are preferably transparent electrode layers, preferably comprising, and highly preferably consisting of, ITO (indium tin oxide).

[0056] The second electrode (404) is preferably a patterned electrode having a fishbone pattern as shown in Figure 1(a). The second electrode (404) is preferably a pixelated electrode that defines pixel areas.

[0057] The first electrode (403) is preferably a continuous electrode layer and may be disposed across the entire substrate facing the other substrate.

[0058] In another preferred embodiment, the first electrode (403) also has a pattern, such as a fishbone pattern, and is also a pixel electrode defining pixel regions, the pixel electrodes being disposed within each pixel region and connected to a nonlinear switch element, optionally including a micro-slit pattern.

[0059] The third electrode (405) may be a continuous electrode or may be a patterned electrode, for example having a fishbone pattern.

[0060] Preferred electrode patterns for the first (403) and third electrodes (405) are shown in Figures 1(b), (c), (d) and (e), where the dark areas indicate the electrode material (such as ITO).

[0061] Each bottom electrode is connected to a non-linear element or addressing means, preferably a TFT, very preferably a TFT based on polycrystalline or amorphous silicon or a metal oxide material such as IGZO.

[0062] Further modifications to the electrode structure can be designed and implemented by one skilled in the art depending on the type of individual display, for example for PS-VA displays, multi-domain alignment of LC molecules can be induced by providing electrodes with slits and / or bumps or protrusions to produce two or more different tilt alignment directions.

[0063] The substrates (401, 402) used in the C-PSA display according to the invention are preferably glass substrates. Plastic substrates are preferably used for flexible displays. These plastic substrates preferably have low birefringence. Examples of suitable and preferred plastic substrates are polycarbonate (PC), polyethersulfone (PES), polycyclic olefine (PCO), polyarylate (PAR), polyetheretherketone (PEEK) or colourless polyimide (CPI) substrates.

[0064] At least one of the first and second substrates (401, 402) must be transparent to the optical radiation used to polymerize the polymerizable compound used in the method according to the invention.

[0065] The first and / or second substrate (401, 402) may carry further layers or components, including but not limited to color filters, TFT arrays, black matrices, polyimide coatings or other components typically provided on the substrates of PSVA displays.

[0066] Preferably at least one of the first and second substrates (401, 402), more preferably each of the first and second substrates (401, 402) is provided with an alignment layer, usually provided on an electrode so as to be in contact with the liquid crystal medium.

[0067] The alignment layer controls the alignment direction of the LC molecules in the LC layer. In the C-PSA display according to the present invention, the alignment layer is selected to give the LC molecules a homeotropic alignment, i.e., the long axes of the LC molecules are perpendicular to the surface of the nearest substrate, but the long axes of the LC molecules are also slightly tilted relative to the surface of the substrate. For example, such an alignment layer may comprise polyimide and may be rubbed or prepared by a photoalignment method.

[0068] If the substrates (401, 402) are provided with an alignment layer prepared by photopolymerization and / or photoalignment, at least one of the substrates must be transparent to the optical radiation used for photopolymerization or photoalignment of the alignment layer material or its precursor.

[0069] Preferably, the tilt angle of the longitudinal axis of the LC molecules located near the surface of the substrate with respect to said substrate is greater than 0° and 20°, preferably 0.1° to 20°, very preferably 0.2° to 3.5°.

[0070] Preferably, a C-PSA display according to the present invention comprises both a first and a second alignment layer, preferably comprising a polyimide.

[0071] In a preferred embodiment, the alignment layer is formed by depositing a solution of the alignment layer material, e.g. a polyimide, or a precursor thereof, e.g. a polyimide precursor, onto a substrate, and optionally curing the alignment layer material or its precursor by exposure to heat and / or actinic radiation, e.g. UV radiation.

[0072] The alignment layer material or its precursor may be deposited on the substrate by, for example, a coating or printing method.

[0073] If a solvent is used in the deposition of the alignment layer material, it is preferably dried or evaporated after deposition. Evaporation of the solvent may be accelerated, for example, by application of heat and / or reduced pressure.

[0074] The preferred method of curing the alignment layer is thermal curing and photocuring, and very preferably photocuring. Photocuring is carried out, for example, by exposure to UV radiation. The appropriate curing conditions can be selected by those skilled in the art according to their own common knowledge and / or as described in the literature, depending on the precursor material used. For commercially available materials, the appropriate process and / or curing conditions are often provided together with the sale or sample of the material.

[0075] A C-PSA display according to the present invention may contain further components not shown in Fig. 4, such as color filters, black matrices, passivation layers, optical retardation layers, transistor elements for addressing individual pixels, etc. These components are well known to those skilled in the art and may be employed without inventive effort.

[0076] The present invention further relates to a method for manufacturing a C-PSA mode LC display, comprising steps a) to e) as described above and below.

[0077] 6 and 7 illustrate a method for preparing a C-PSA display according to the prior art (FIG. 6) compared to a method for preparing a C-PSVA display according to the present invention (FIG. 7).

[0078] FIG. 6(a) shows a prior art C-PSA display (601), comprising a first substrate (602) with a first unpatterned ITO electrode (603) and an alignment layer, e.g. of polyimide (604), a second substrate (605) with a second ITO electrode (606) with a fishbone pattern and an alignment layer, e.g. of polyimide (607), a color filter (608) and a layer of LC medium (609) comprising LC molecules (610), polymerizable compound(s) (611) and a chiral dopant (not shown).

[0079] As shown in FIG. 6(b), when a voltage is applied to the first and second electrodes (603, 606), the LC molecules (610) are tilted at a certain tilt angle.

[0080] Furthermore, the electric field generated by the patterned second electrode as described above causes the tilted LC molecules to azimuthally align in the substrate plane defined by the fishbone pattern of the second electrode (606), also known as multi-domain alignment, which results in a preferred alignment direction of the LC molecules aligned horizontally in the addressed (i.e., driven or field-on) state.

[0081] Upon irradiation with UV light, the polymerizable compound(s) (611) is polymerized to form a polymer structure on the substrate, as shown in Figure 6(c), so that the pretilt and azimuthal angles (or multi-domain alignment) of the LC molecules are permanently fixed, even after the voltage is switched off, as shown in Figure 6(d). However, in the area covering the gap between the pixelated second electrodes, the induced tilt is non-uniform and the LC molecules tend to align more vertically.

[0082] Figure 7(a) shows a C-PSA display (701) of the present invention, comprising a first substrate (702) with a first unpatterned ITO electrode (703) and an alignment layer, e.g. of polyimide (704), a second substrate (705) with a second patterned ITO electrode (706), e.g. of a fishbone pattern, and an alignment layer, e.g. of polyimide (707), a color filter (708) and a layer of LC medium (709) comprising LC molecules (710), polymerizable compound(s) (711) and a chiral dopant (not shown). The display further comprises an insulating layer (712) and a third unpatterned electrode (713).

[0083] First, as shown in FIG. 7(b), an electric field is applied to the first and second electrodes (703, 706) while the third electrode is grounded (to prevent it from floating due to capacitive coupling with a nearby loaded electrode), resulting in the alignment of the LC molecules (710) into a slightly tilted orientation with a constant pretilt angle and multi-domain alignment, similar to the display of FIG. 6.

[0084] A voltage is then also applied to the third electrode (713), as shown in Figure 7(c). Preferably the third electrode is switched to the same potential as the second electrode. This creates a uniform linear electric field which superimposes the non-uniform electric field created in the second electrode (706). As a result, it creates a uniform alignment of the LC molecules in the area covering the gap between the pixelated second electrodes.

[0085] Furthermore, the additional electric field force generated by the third electrode improves the alignment of the LC molecules in the azimuthal direction both in the regions over the patterned electrodes and in the regions over the gaps between the pixelated electrode structures, resulting in improved uniformity of the multi-domain alignment of the planar aligned LC molecules in the azimuthal addressed (i.e., driven or field-on) state.

[0086] Upon irradiation with UV light, the polymerizable compound(s) are polymerized to form a polymer structure on the substrate, as shown in Fig. 7(d), so that the multi-domain alignment along the pretilt and azimuthal angles is permanently fixed even after the voltage is switched off, as shown in Fig. 7(e).

[0087] Overall the third electrode therefore improves the alignment of the LC molecules in the driven display, leading to enhanced transmittance.

[0088] In a preferred embodiment, a C-PSA LC display according to the present invention additionally comprises first and second compensation films (not shown in FIG. 7) sandwiching the display and preferably selected from biaxial compensation films.

[0089] The first and second compensation films are preferably selected from compensation films known from the prior art for use in PSVA displays. Preferably, a polymer film is used, such as a COP (cycloolefin polymer) film (e.g. available as Zeonex® from Nippon Zeon Co.), preferably biaxially stretched to provide the desired retardation in the film plane and thickness direction.

[0090] Preferably, the first and second biaxial compensation films exhibit the optical properties of an A-plate and a C-plate, which can be achieved, for example, by biaxial stretching. Preferably, the retardation in the film plane, R0, is 30 to 80 nm, most preferably 50 nm, and the retardation in the thickness direction, R th is -150 to -200 nm, and most preferably -175 nm.

[0091] The individual process steps a) to e) are explained in more detail below.

[0092] In step a), a C-PSA display is provided which comprises the components as described above and below.

[0093] In step b) a layer of an LC medium having negative dielectric anisotropy and comprising components A, B, C and optionally D as described above and below is distributed between the first and second substrates such that the LC medium is in contact with the first and second alignment layers, if alignment layers are present. The LC medium preferably has a nematic phase at room temperature.

[0094] The LC medium may be dispensed or filled onto the substrate or within the display, respectively, by methods conventionally used by display manufacturers.

[0095] Preferably the LC medium is deposited on the substrate using one of the following deposition methods: one drop filling (ODF), inkjet printing, spin coating, slit coating, flexographic printing or equivalent methods.

[0096] The preferred method is inkjet printing.

[0097] Another preferred method is the ODF method, which preferably comprises the following steps: b1) dispensing a droplet or an array of droplets of an LC medium onto a first substrate; and b2) providing a second substrate on top of the first substrate having droplets of LC medium dispensed thereon, preferably under vacuum conditions, causing the droplets of LC medium to spread and form a continuous layer between the two substrates.

[0098] The applied LC medium forms a thin, uniform film with a thickness equal to the target final cell gap of the display.

[0099] Preferably the display according to the invention comprises fixing means for fixing the first and second substrates at a constant distance from each other with their planes parallel to each other, preferably the fixing means comprising a sealant material and a spacer material to maintain a constant cell gap and LC layer thickness.

[0100] Preferably the first and second substrates are fixed or adhered by fixing means, such as a sealant material, provided on the substrate, preferably in areas proximate to the edges of the substrate.

[0101] Preferably the sealant material is deposited on the first substrate or between the first and second substrates before the LC medium is dispensed between the first and second substrates.

[0102] A sealant material is provided on the first substrate or between the first and second substrates, preferably in the area between the LC medium and the edges of each substrate. The sealant material is, for example, a cross-linked polymer formed from a curable polymer precursor. The sealant material is then cured, preferably after the first and second substrates are assembled to form the LC cell, but before photopolymerization of the polymerizable compound contained in the LC medium. Preferably, the sealant material is cured by exposure to heat and / or light radiation.

[0103] The spacer material consists for example of transparent glass or plastic beads. In a preferred embodiment the spacers are dispensed between the substrates together with the LC medium.

[0104] In another preferred embodiment, to maintain a constant cell gap and LC layer thickness, the display includes a spacer material, eg an optical spacer, on the outside of the LC layer, eg on the black matrix, and the LC layer does not include a spacer material.

[0105] Suitable sealants and spacers are known to those skilled in the art and are commercially available.

[0106] The layer thickness of the LC medium is preferably between 0.5 and 10 μm, very preferably between 2 and 3.5 μm.

[0107] The optical retardation of the layer of the LC medium is preferably between 200 and 1000 nm, very preferably between 400 and 500 nm.

[0108] The helical pitch produced in the LC medium by the chiral dopant(s) is preferably between 4 and 30 μm, preferably between 8 and 20, very preferably between 12 and 16 μm.

[0109] In step c) a voltage is applied to the first and second electrodes, preferably the third electrode, to generate a pretilt angle of the LC molecules relative to the substrate as discussed above. A suitable voltage can be selected by a person skilled in the art based on general and common knowledge. A preferred voltage is, for example, 5-50V, more preferably 10-40V, and very preferably 15-30V.

[0110] Then, in step d), a voltage is applied to the electrodes while the polymerizable compound contained in the LC medium is polymerized in the LC medium between the substrates by in situ polymerization.

[0111] Upon polymerization, the polymerizable compound forms a polymer, which causes the LC molecules in the LC medium to have a certain tilt angle. Without wishing to be bound by any 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 to form a polymer layer on the substrate or electrode or on an alignment layer disposed thereon. Microscopy data (e.g., SEM and AFM) confirm that at least a portion of the formed polymer is deposited at the LC / substrate interface.

[0112] The polymerization can be carried out in one step, or in a preferred embodiment the polymerization is carried out in two steps.

[0113] In a first step, which corresponds to process step d) as described above and below, the polymerizable compound is polymerized in situ in the LC medium between the substrates while applying a voltage to the electrodes to generate a tilt angle. In a second step, which corresponds to process step e) as described above and below, the polymerizable compound that did not react in the first step is polymerized without an applied voltage ("final cure").

[0114] Suitable and preferred polymerization methods are, for example, thermal or photopolymerization, preferably photopolymerization, especially UV-induced photopolymerization, which can be achieved by exposing the polymerizable compound to UV radiation.

[0115] Preferred embodiments of the method for producing a C-PSA display according to the invention include one or more of the following features:

[0116] The polymerizable medium is exposed to UV light within the display, comprising a two-step process in which a first UV exposure step ("UV1 step") with application of voltage creates a tilt angle, and a second UV exposure step ("UV2 step") without application of voltage completes the polymerization;

[0117] The polymerizable medium is exposed to UV light, preferably at least in the UV2 step, more preferably in both the UV1 and UV2 steps, in displays produced by UV-LED lamps;

[0118] The polymerizable medium is exposed to UV light in the display, produced by energy-saving UV lamps (also known as "green UV lamps"). These lamps are characterized by a relatively low intensity (1 / 100 to 1 / 10 of conventional UV1 lamps) in the absorption spectrum from 300 to 380 nm and are preferably used in the UV2 process, but optionally also in the UV1 process if high intensities need to be avoided for the process.

[0119] The polymerizable medium is exposed to UV light in the display produced by a UV lamp with an emission spectrum shifted to longer wavelengths, preferably above 340 nm, more preferably below 350-370 nm, very preferably 355-368 nm to avoid short UV light exposure in the PSA process.

[0120] Both the use of lower intensity and the shift of the UV to longer wavelengths protect the organic layers from damage that can be caused by UV light.

[0121] A preferred embodiment of the present invention relates to a process for preparing a C-PSA display as described above and below, comprising one or more of the following features, including any desired combination thereof:

[0122] Irradiating the polymerizable LC medium with UV light in two steps, including a first UV exposure step ("UV-1 step") in which a voltage is applied to generate a tilt angle, and a second UV exposure step ("UV-2 step") in which no voltage is applied to complete the polymerization,

[0123] The polymerizable LC medium is preferably irradiated with 0.5 mW / cm in the wavelength range of 300 to 380 nm, preferably in the UV2 step and optionally also in the UV1 step. 2 ~10mW / cm 2and irradiating the sample with UV light generated by a UV lamp having an intensity of

[0124] irradiating the polymerizable LC medium with UV light having a wavelength of ≧340 nm and ≦420 nm, preferably above 350 nm, preferably in the range of 340-400 nm, more preferably in the range of 350-390 nm, very preferably in the range of 360-380 nm and most preferably in the range of 360-368 nm,

[0125] -UV light is irradiated using a UV-LED lamp.

[0126] This preferred method can be carried out, for example, by using a desired UV lamp, or by using a bandpass filter and / or a cutoff filter that substantially transmits UV light having a desired wavelength and substantially blocks light having an undesired wavelength. For example, if irradiation with UV light having a wavelength λ of 300 to 400 nm is desired, UV irradiation can be carried out using a wide bandpass filter that substantially transmits wavelengths λ of more than 300 nm and less than 400 nm. If irradiation with UV light having a wavelength λ of more than 340 nm is desired, UV irradiation can be carried out using a cutoff filter that substantially transmits wavelengths λ of more than 340 nm.

[0127] Preferably, the UV irradiation is carried out using a UV-LED lamp.

[0128] The use of UV-LED lamps with only one narrow emission peak in the PSA process has several advantages, such as more effective light energy transfer to the polymerizable compounds in the LC medium, depending on the selection of suitable polymerizable compounds that absorb at the emission wavelength of the LED lamp. This allows the UV intensity and / or UV exposure time to be reduced, thus shortening the cycle time and saving energy and production costs. Another advantage is that the narrow emission spectrum of the lamp makes it easier to select a suitable wavelength for photopolymerization.

[0129] Very preferably, the UV light source is a UV-LED lamp emitting a wavelength in the range of 340-400 nm, more preferably in the range of 350-390 nm, very preferably in the range of 360-380 nm, most preferably in the range of 360-368 nm. A UV-LED lamp emitting UV light with a wavelength of 365 nm is particularly preferred.

[0130] Preferably, the UV-LED lamp emits light with an emission peak having a full width half maximum (FWHM) of 30 nm or less.

[0131] UV-LED lamps are commercially available, for example from Dr. Hoenle, Germany or Primelite, Germany or IST Metz, Germany, and have emission wavelengths of, for example, 365, 385, 395 and 405 nm.

[0132] This preferred method allows for the manufacture of displays using longer wavelength UV, thereby reducing or avoiding the deleterious and damaging effects of the shorter wavelength components of UV light.

[0133] The UV radiation energy is generally 6 to 100 J, depending on the conditions of the manufacturing process.

[0134] Preferably, the LC medium used in the display according to the invention is A) a liquid crystal component A containing mesogens or liquid crystal molecules; B) a polymerizable component B comprising one or more polymerizable, preferably polymerizable mesogenic compounds; C) one or more chiral additives, preferably selected from chiral dopants; D) Optionally, one or more further additives, preferably selected from stabilizers and polymerization initiators Includes.

[0135] When used in a display according to the invention, the liquid crystal component A) of the LC medium, also referred to hereinafter as "LC host mixture", preferably comprises only LC compounds selected from low molecular weight compounds which are non-polymerizable.

[0136] The polymerisable compounds of the polymerisable component B of the LC medium are preferably selected from the formula M

[0137] [ka]

[0138] In the formula, the individual radicals, which are identical or different at each occurrence, each have the following meanings independently of one another: R a and R b is P, P-Sp-, H, F, Cl, Br, I, -CN, -NO2, -NCO, -NCS, -OCN, -SCN, SF5, or a linear or branched alkyl having 1 to 25 C atoms, provided that in addition one or more non-adjacent CH2 groups are each independently -C(R 0 )=C(R 00 )-, -C≡C-, -N(R 00 )-, -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O-, provided that in addition one or more H atoms may be replaced by F, Cl, Br, I, CN, P or P-Sp-, provided that B 1 and / or B. 2 contains saturated C atoms, and R a and / or R b may also represent a group which can be linked to this saturated C atom via a spiro bond, However, the group R a and R b at least one of which represents or contains the group P or P-Sp-, P is a polymerizable group, Sp is a spacer group or a single bond; B 1 and B. 2is preferably an aromatic, heteroaromatic, alicyclic or heterocyclic group having 4 to 25 ring atoms, which may also contain fused rings, which may be mono- or polysubstituted by L, Z b -O-, -S-, -CO-, -CO-O-, -OCO-, -O-CO-O-, -OCH2-, -CH2O-, -SCH2-, -CH2S-, -CF2O-, -OCF2-, -CF2S-, -SCF2-, -(CH2) n1 -, -CF2CH2-, -CH2CF2-, -(CF2) n1 -, -CH=CH-, -CF=CF-, -C≡C-, -CH=CH-COO-, -OCO-CH=CH-, -CR 0 R 00 - or a single bond, R 0 and R 00 each independently represent H or alkyl having 1 to 12 C atoms, m represents 0, 1, 2, 3 or 4; n1 represents 1, 2, 3 or 4; L is P, P-Sp-, OH, CH2OH, F, Cl, Br, I, -CN, -NO2, -NCO, -NCS, -OCN, -SCN, -C(=O)N(R x )2, -C(=O)Y 1 , -C(=O)R x , -N(R x 2) optionally substituted silyl, optionally substituted aryl having 6 to 20 C atoms, or linear or branched alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy having 1 to 25 C atoms, with the proviso that in addition one or more H atoms may be replaced by F, Cl, P or P-Sp-, P and Sp have the meanings given above, Y 1 represents a halogen, R xrepresents P, P-Sp-, H, halogen, linear, branched or cyclic alkyl having 1 to 25 C atoms (with the proviso that in addition, one or more non-adjacent CH groups may be replaced by -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O- in such a way that O and / or S atoms are not directly linked to each other, and with the proviso that in addition, one or more H atoms may be replaced by F, Cl, P or P-Sp-), an optionally substituted aryl or aryloxy group having 6 to 40 C atoms, or an optionally substituted heteroaryl or heteroaryloxy group having 2 to 40 C atoms.

[0139] Preferred compounds of formula M are 1 and B. 2 but in each case independently of one another, 1,4-phenylene, naphthalene-1,4-diyl, naphthalene-2,6-diyl, phenanthrene-2,7-diyl, anthracene-2,7-diyl, fluorene-2,7-diyl, coumarin, flavone (in addition, one or more CH groups in these groups may be replaced by N), cyclohexane-1,4-diyl (in addition, one or more non-adjacent CH groups may be replaced by O and / or S), 1,4-cyclohexenylene, bicyclo[1 and R is selected from the group consisting of: bicyclo[2.2.2]octane-1,4-diyl, spiro[3.3]heptane-2,6-diyl, piperidine-1,4-diyl, decahydronaphthalene-2,6-diyl, 1,2,3,4-tetrahydronaphthalene-2,6-diyl, indan-2,5-diyl or octahydro-4,7-methanoindan-2,5-diyl, all of which groups may be unsubstituted or mono- or polysubstituted by L as defined above.

[0140] Particularly preferred compounds of formula M are 1 and B. 2 denote, in each case independently of one another, 1,4-phenylene, 1,3-phenylene, naphthalene-1,4-diyl or naphthalene-2,6-diyl.

[0141] Highly preferred compounds of formula M are selected from the following formulae:

[0142] [ka]

[0143] [ka]

[0144] [ka]

[0145] [ka]

[0146] [ka]

[0147] [ka]

[0148] In the formulae, the individual radicals, which are identical or different at each occurrence, each have the following meanings independently of one another: P 1 , P 2 , P 3 is a polymerizable group, preferably selected from vinyloxy, acrylate, methacrylate, fluoroacrylate, chloroacrylate, oxetane and epoxy; Sp 1 , Sp 2 , Sp 3 is a single bond or a spacer group, provided that in addition there is one or more groups P 1 -Sp 1 -, P 2 -Sp 2 - and P 3 -Sp 3 - is Raa where any group P 1 -Sp 1 -, P 2 -Sp 2 - and P 3 -Sp 3 -At least one of the following is R aa preferably -(CH2) p1 -, -(CH2) p1 -O-, -(CH2) p1 -CO-O- or -(CH2) p1 -O-CO-O-, wherein p1 is an integer from 1 to 12; R aa is H, F, Cl, CN or linear or branched alkyl having 1 to 25 C atoms (provided that in addition one or more non-adjacent CH groups are in each case independently of one another such that O and / or S atoms are not directly linked to one another) -C(R 0 )=C(R 00 )-, -C≡C-, -N(R 0 )-, -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O-, provided that in addition one or more H atoms are replaced by F, Cl, CN or P 1 -Sp 1 -), particularly preferably linear or branched, optionally mono- or polyfluorinated alkyl, alkoxy, alkenyl, alkynyl, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyl or alkylcarbonyloxy having 1 to 12 C atoms, with the proviso that the alkenyl and alkynyl groups have at least 2 C atoms and the branched groups have at least 3 C atoms, with the proviso that R aa is group P 1 , P 2 or P 3 does not mean or include, R 0 , R 00 is H or alkyl having 1 to 12 C atoms, R y and R z is H, F, CH3 or CF3, X1 , X 2 , X 3 is -CO-O-, -O-CO- or a single bond, Z M1 -O-, -CO-, -C(R y R z )- or -CF2CF2-, Z M2 , Z M3 is -CO-O-, -O-CO-, -CH2O-, -OCH2-, -CF2O-, -OCF2- or -(CH2) n where n is 2, 3 or 4; L is F, Cl, CN, or a linear or branched alkyl, alkoxy, thioalkyl, alkenyl, alkynyl, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy, or alkoxycarbonyloxy having 1 to 12 C atoms which may be monofluorinated or polyfluorinated; L', L" are H, F or Cl; k is 0 or 1; r is 0, 1, 2, 3 or 4; s is 0, 1, 2 or 3; t is 0, 1 or 2; x is 0 or 1.

[0149] Compounds of the formulae M2, M13 and M33, in particular those containing only two polymerizable groups P 1 and P 2 Highly preferred are bireactive compounds comprising:

[0150] Compounds selected from the formulae M17 to M32, in particular from the formulae M20, M22, M24, M27, M30 and M32, in particular compounds having only three polymerizable groups P 1 , P 2 and P 3 Further preferred are trireactive compounds comprising:

[0151] In the compounds of formulae M1 to M33, [ka]

[0152] In the formula, L has, identically or differently, one of the meanings given above and below at each occurrence, preferably F, Cl, CN, NO2, CH3, C2H5, C(CH3)3, CH(CH3)2, CH2CH(CH3)C2H5, CH=CH2, C(CH3)=CH2, SCH3, OCH3, OC2H5, COCH3, COC2H5, COOCH3, COOC2H5, CF3, OCF3, OCHF2, OC2F5 or P-Sp-, very preferably F, Cl, CN, CH3, C2H5, CH=CH2, C(CH3)=CH2, SCH3, OCH3, COCH3, OCF3 or P-Sp-, more preferably F, Cl, CH3, CH=CH2, C(CH3)=CH2, SCH3, OCH3, COCH3 or OCF 3、 Most preferred is F, SCH3 or OCH3.

[0153] Preferred compounds of formulae M1 to M33 are 1 , P 2 and P 3 represents an acrylate, methacrylate, oxetane or epoxy group, very preferably an acrylate or methacrylate group, most preferably a methacrylate group.

[0154] Further preferred compounds of the formulae M1 to M33 are Sp 1 , Sp 2 and Sp 3 is a single bond.

[0155] Further preferred compounds of the formulae M1 to M33 are Sp 1 , Sp 2 and Sp 3 represents a single bond, and Sp 1 , Sp 2 and Sp 3 The other one is different from a single bond.

[0156] Further preferred compounds of the formulae M1 to M33 are those which contain a group Sp different from a single bond. 1 , Sp 2 and Sp3 Ga-(CH2) s1 represents -X"-, where s1 is an integer from 1 to 6, preferably 2, 3, 4 or 5, and X" is a link to an adjacent benzene ring and is -O-, -O-CO-, -CO-O-, -O-CO-O- or a single bond.

[0157] Particular preference is given to LC media which comprise one, two or three polymerisable compounds of the formula M.

[0158] Further preference is given to an LC medium which comprises two or more direactive polymerisable compounds of formula M, preferably selected from formulae M1 to M16 and M33, very preferably selected from formulae M2, M13 and M33.

[0159] Further preferred is an LC medium comprising one or more direactive polymerisable compounds of the formula M, preferably selected from the formulae M1 to M16 and M33, very preferably from the formulae M2, M13 and M33, and one or more trireactive polymerisable compounds of the formula M, preferably selected from the formulae M17 to M32, very preferably from the formulae M20, M22, M24, M27, M30 and M32.

[0160] Further preferred is an LC medium comprising one or more polymerisable compounds of formula M, very preferably selected from the formulae M2, M13, M22, M24, M27, M30, M32 and M33, in which at least one r is not 0 or at least one of s and t is not 0, and in which L is selected from the preferred groups indicated above, most preferably from F, OCH3 and SCH3.

[0161] Further preference is given to an LC medium comprising one or more polymerisable compounds, preferably selected from formula M, very preferably from formulae M1 to M33, and exhibiting absorption in the wavelength range from 320 to 380 nm.

[0162] Further preferred are LC media comprising one or more polymerizable compounds selected from Table D. Among these, 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, RM-122, RM-139, RM-142, RM-143, RM-148 to RM-158, RM-164, RM-165 and RM-166 to RM-178 are particularly preferred.

[0163] More preferred compounds of formulae M1 to M33 are those selected from Table D below, in particular those of formulae RM-1, RM-4, RM-8, RM-17, RM-19, RM-35, RM-37, RM-39, RM-40, RM-41, RM-48, RM-52, RM-54, RM-57, RM-64, RM-74, RM-76, RM-88, RM-92, RM-102, RM-10 3, RM-109, RM-116, RM-117, RM-120, RM-121, RM-122, RM-139, RM-140, RM-142, RM-143, RM-148, RM-152, RM-154, RM-155, RM157, RM-158, RM-164, RM-165 and RM-166 to RM-178.

[0164] Particular preference is given to LC media which comprise one, two or three polymerisable compounds of the formula M or selected from the formulae M1 to M33.

[0165] Further preferred is an LC medium wherein the polymerisable component B) consists exclusively of polymerisable compounds of formula M.

[0166] In another preferred embodiment, component B) comprises, in addition to or instead of the polymerizable compounds of formula M according to the above preferred subformulae and subgroups, one or more polymerizable mesogenic compounds comprising one or more polymerizable groups and one or more polar anchor groups, e.g. selected from hydroxy, carboxy, amino or thiol groups. These compounds function as self-aligning (SA) additives and are useful for SA mode displays according to the present invention. Suitable and preferred polymerizable mesogenic SA additives of this type are selected from compounds of formula I or M1 to M31, provided that they contain at least one group B 1 , B 2 , R a , R b , R x , L, Sp, Sp 1 , Sp 2 , Sp 3 or R aa is substituted with a hydroxy, carboxy, amino or thiol group, preferably a hydroxy group. Further preferred polymerizable mesogenic SA additives of this type are selected from formulae SA-9 to SA-34 in Table E.

[0167] Preferably, the proportion of the polymerizable compound of component B) in the LC medium is less than 0.05 to 3%, more preferably 0.1 to 2.5%, very preferably 0.1 to 1.5%, and most preferably 0.2 to 1.0%. In another preferred embodiment, the proportion of the polymerizable compound of component B) in the LC medium is less than 1.5%, more preferably 0.05 to 1.0%, very preferably 0.1 to 0.8%, and most preferably 0.1 to 0.5%.

[0168] The polymerizable compounds of formula I and M1 to M33 are known to those skilled in the art and can be prepared analogously to processes described in standard texts on organic chemistry such as, for example, Houben-Weyl, Methoden der organischen Chemie [Methods of Organic Chemistry], Thieme-Verlag, Stuttgart.

[0169] For example, acrylic or methacrylic esters can be prepared by esterification of the corresponding alcohols with acid derivatives, e.g. (meth)acryloyl chloride or (meth)acrylic anhydride, in the presence of a base, e.g. pyridine or triethylamine, 4-(N,N-dimethylamino)pyridine (DMAP), etc. Alternatively, esters can be prepared by esterification of alcohols with (meth)acrylic acid in the presence of a dehydrating reagent, e.g. according to Stäglich, using dicyclohexylcarbodiimide (DCC), N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide (EDC) or N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride and DMAP.

[0170] In addition to components A and B the LC medium preferably comprises a component C which comprises one or more optically active compounds selected from chiral dopants.

[0171] The helical twisting power of the chiral dopant(s) and their proportion in the LC medium are preferably selected in such a way that the helical pitch produced in the LC medium is between 4 and 30 μm, more preferably between 8 and 20 μm, very preferably between 12 and 16 μm.

[0172] The proportion of chiral dopant(s) in the LC medium is preferably between 0.01 and 6%, very preferably between 0.05 and 4%, more preferably between 0.1 and 2%.

[0173] Suitable and preferred chiral dopants are set out below in Table B. Preferred chiral dopants are for example selected from R- or S-1011, R- or S-2011, R- or S-3011, R- or S-4011 or R- or S-5011.

[0174] In another preferred embodiment, the LC medium comprises one or more polymerization initiators.

[0175] Suitable conditions for polymerization and suitable types and amounts of initiators are known to those skilled in the art and described in the literature. For example, commercially available photoinitiators Irgacure 651®, Irgacure 184®, Irgacure 907®, Irgacure 369® or Darocure 1173® (Ciba) are suitable for free radical polymerization.

[0176] When the initiator is added to the LC medium, the content is preferably 0.001 to 1% by weight, particularly preferably 0.001 to 0.5% by weight.

[0177] The polymerizable compounds according to the invention are also suitable for polymerization without initiators, which entails considerable advantages, such as, for example, lower material costs and, in particular, reduced contamination of the LC medium by possible residual amounts of initiators or their decomposition products.

[0178] Thus, the polymerization can also be carried out without the addition of an initiator. Thus, in another preferred embodiment the LC medium does not comprise a polymerization initiator.

[0179] In another preferred embodiment, the LC medium further comprises one or more stabilizers, e.g. to prevent undesired spontaneous polymerization of the RM during storage or transport, of the polymerizable component of the cholesteric liquid crystal medium. Suitable types and amounts of stabilizers are known to those skilled in the art and described in the literature. Commercially available stabilizers, e.g. from the Irganox® series (Ciba), such as Irganox® 1076, are particularly suitable.

[0180] When a stabilizer is used, the proportion of the stabilizer based on the RM or the polymerizable component (component A) is preferably 10 to 50,000 ppm, particularly preferably 50 to 5,000 ppm.

[0181] In another preferred embodiment of the invention the LC medium comprises one or more further stabilizers, preferably selected from the group consisting of the following formulae:

[0182] [ka]

[0183] In the formula, the individual radicals each, independently of one another, have the following meanings, which are identical or different at each occurrence: R a~d is linear or branched alkyl having 1 to 10, preferably 1 to 6 and very preferably 1 to 4 C atoms, most preferably methyl, X S is H, CH3, OH or O ● and A S is an optionally substituted linear, branched or cyclic alkylene having 1 to 20 C atoms, n is an integer of 1 to 6, and preferably 3.

[0184] Preferred stabilizers of formula S3 are selected from formula S3A:

[0185] [ka]

[0186] In the formula, n2 is an integer from 1 to 12, provided that the group (CH2) n2 One or more H atoms in may be optionally replaced by methyl, ethyl, propyl, butyl, pentyl or hexyl.

[0187] Highly preferred stabilizers are selected from the group consisting of the following formulae:

[0188] [ka]

[0189] [ka]

[0190] [ka]

[0191] [ka]

[0192] In a preferred embodiment the LC medium comprises one or more stabilizers selected from the group consisting of formulae S1-1, S2-1, S3-1, S3-1 and S3-3.

[0193] In a preferred embodiment the LC medium comprises one or more stabilizers selected from Table C below.

[0194] The proportion of stabilizers such as those of the formulae S1 to S3 in the LC medium is preferably between 10 and 500 ppm, very preferably between 20 and 200 ppm.

[0195] In another preferred embodiment the LC medium according to the invention comprises a self alignment (SA) additive, preferably in a concentration of 0.1 to 2.5%.

[0196] In another preferred embodiment the LC medium according to the invention comprises a self alignment (SA) additive, preferably in a concentration of 0.1 to 2.5%.

[0197] In a preferred embodiment, the SA-VA display according to the present invention does not include a polyimide alignment layer.In another preferred embodiment, the SA-VA display according to the preferred embodiment includes a polyimide alignment layer.

[0198] Preferred SA additives for use in this preferred embodiment are selected from compounds comprising a mesogenic group and a linear or branched alkyl side chain terminated with one or more polar anchor groups selected from hydroxy, carboxy, amino or thiol groups.

[0199] Further preferred SA additives comprise one or more polymerizable groups linked to a mesogenic group, optionally via a spacer group. These polymerizable SA additives can be polymerized in the LC medium under conditions similar to those applied to the RM in the PSA process.

[0200] Suitable SA additives for inducing homeotropic alignment, particularly for use in SA-VA mode displays, are disclosed, for example, in US Patent Application Publication No. 2013 / 0182202, US Patent Application Publication No. 2014 / 0838581, US Patent Application Publication No. 2015 / 0166890 and US Patent Application Publication No. 2015 / 0252265.

[0201] In another preferred embodiment the LC medium or polymer stabilized SA-VA display according to the invention comprises one or more self-aligning additives selected from Table E below.

[0202] In another preferred embodiment the LC medium according to the invention comprises one or more SA additives, preferably selected from Table E, in a concentration of 0.1-5%, very preferably 0.2-3%, most preferably 0.2-1.5%.

[0203] The LC media according to the invention may also comprise further additives selected without limitation from the following list: antioxidants, free radical scavengers, surfactants, antifoaming agents, wetting agents, lubricants, dispersants, hydrophobizing agents, adhesives, flow improvers, degassing agents, diluents, reactive diluents, adjuvants, colorants, dyes, pigments and nanoparticles.

[0204] The LC medium preferably has a nematic LC phase at room temperature.

[0205] In addition to the above polymerizable compounds and additives, the LC medium for use in an LC display according to the present invention comprises an LC mixture ("host mixture") comprising one or more, preferably two or more LC compounds selected from non-polymerizable low molecular weight compounds and at least one compound of formula II. These LC compounds are selected such that they are stable and / or non-reactive towards polymerization reactions under the conditions applied for the polymerization of the polymerizable compounds.

[0206] Particularly preferred embodiments of such LC media are given below.

[0207] Preferably, the LC medium or its component A) (host mixture) comprises one or more compounds of formula II.

[0208] [ka]

[0209] In the formula, the individual radicals each, independently of one another, have the following meanings, which are identical or different at each occurrence: R 1 and R 2 is a linear, branched or cyclic alkyl group having 1 to 25 C atoms (provided that one or more non-adjacent CH2 groups are not directly connected to each other by O atoms and / or S atoms, respectively, and are -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O-, CR 0 =CR 00 -, -C≡C-, [ka] where one or more H atoms may be replaced by F or Cl), preferably alkyl or alkoxy having 1 to 6 C atoms, R 0 , R 00 is H or alkyl having 1 to 12 C atoms, A 1 and A 2 From the following formula, [ka] are preferably radicals selected from the formulae A1, A2, A3, A4, A5, A6, A9 and A10, very preferably from the formulae A1, A2, A3, A4, A5, A9 and A10, Z 1 and Z 2 is -CH2CH2-, -CH=CH-, -CF2O-, -OCF2-, -CH2O-, -OCH2-, -CO-O-, -O-CO-, -C2F4-, -CF=CF-, -CH=CH-CHO- or a single bond, preferably a single bond; L 1 , L 2 , L 3 and L 4 is F, Cl, OCF3, CF3, CH3, CH2F or CHF2, preferably F or Cl, very preferably F, Y is H, F, Cl, CF3, CHF2 or CH3, preferably H or CH3, very preferably H, L C is CH3 or OCH3, preferably CH3; a1 is 1 or 2; a2 is 0 or 1.

[0210] Preferably the LC medium comprises one or more compounds of formula II selected from the group consisting of the compounds of formulae IIA, IIB, IIC and IID.

[0211] [ka]

[0212] During the ceremony R 2A and R 2Bare each independently H, an alkyl or alkenyl group having up to 15 C atoms, which is unsubstituted, monosubstituted with CN or CF3 or at least monosubstituted with a halogen, provided that in addition, one or more CH2 groups in these groups are not linked directly to O atoms, such as -O-, -S-, [ka] may be replaced by -C≡C-, -CF2O-, -OCF2-, -CO-O- or -O-CO-; L 1 ~L 4 each independently represents F, Cl, CF3 or CHF2, Y represents H, F, Cl, CF3, CHF2 or CH3, preferably H or CH3, particularly preferably H, Z 2 , Z 2B and Z 2D each independently represents a single bond, -CHCH-, -CH=CH-, -CFO-, -OCF-, -CHO-, -OCH-, -COO-, -OCO-, -CF-, -CF=CF-, or -CH=CHCHO-; p represents 0, 1 or 2, and q is the same or different and represents 0 or 1 in each occurrence.

[0213] Preferred compounds of formula IIA, IIB, IIC and IID are 2B represents an alkyl or alkoxy group having 1 to 15 C atoms, very preferably (O)C v H 2v+1 where (O) is an oxygen atom or a single bond, and v is 1, 2, 3, 4, 5, or 6.

[0214] Further preferred compounds of formula IIA, IIB, IIC and IID are 2A or R 2B is preferably [ka] (S in the formula 1 is C 1~5 -Alkylene or C 2~5 -alkenylene, S 2 is H, C 1~7 -Alkyl or C 2~7 -alkenyl), and very preferably [ka] It represents or contains a cycloalkyl or cycloalkoxy group selected from the group consisting of:

[0215] More preferred compounds of formula IIA, IIB, IIC and IID are shown below.

[0216] [ka]

[0217] [ka]

[0218] [ka]

[0219] [ka]

[0220] [ka]

[0221] [ka]

[0222] [ka]

[0223] [ka]

[0224] [ka]

[0225] [ka]

[0226] In the formula, the parameter a represents 1 or 2, alkyl and alkyl * each independently represents a linear alkyl group having 1 to 6 C atoms, alkenyl represents a linear alkenyl group having 2 to 6 C atoms, and (O) represents an oxygen atom or a single bond. Alkenyl preferably represents CH2=CH-, CH2=CHCH2CH2-, CH3-CH=CH-, CH3-CH2-CH=CH-, CH3-(CH2)2-CH=CH-, CH3-(CH2)3-CH=CH- or CH3-CH=CH-(CH2)2-.

[0227] Particularly preferred LC media according to the invention comprise one or more compounds of the formulae IIA-2, IIA-8, IIA-10, IIA-16, II-18, IIA-40, IIA-41, IIA-42, IIA-43, IIB-2, IIB-10, IIB-16, IIC-1 and IID-4.

[0228] The proportion of compounds of formulae IIA and / or IIB in the overall mixture is preferably at least 20% by weight. In another preferred embodiment the LC medium comprises one or more compounds of formula III.

[0229] [ka]

[0230] During the ceremony R 11 and R 12 each independently represent H, an alkyl or alkoxy group having 1 to 15 C atoms, with the proviso that one or more CH2 groups in these groups are not directly linked to O atoms, [ka] -C≡C-, -CF2O-, -OCF2-, -CH=CH-, -O-, -CO-O- or -O-CO-, each of which may be replaced independently of the other, in which additionally one or more H atoms may be replaced by halogen; A 3 are, independently of each other in each occurrence, a) a 1,4-cyclohexenylene or 1,4-cyclohexylene group, in which one or two non-adjacent CH groups may be replaced by -O- or -S-; b) a 1,4-phenylene group, in which one or two CH groups may be replaced by N, or c) a group selected from the group consisting of spiro[3.3]heptane-2,6-diyl, 1,4-bicyclo[2.2.2]octylene, naphthalene-2,6-diyl, decahydronaphthalene-2,6-diyl, 1,2,3,4-tetrahydronaphthalene-2,6-diyl, phenanthrene-2,7-diyl and fluorene-2,7-diyl represents provided that groups a), b) and c) may be mono- or polysubstituted by halogen atoms; n represents 0, 1 or 2, preferably 0 or 1; Z 1 represent, independently in each occurrence, -CO-O-, -O-CO-, -CF2O-, -OCF2-, -CHO-, -OCH2-, -CH2-, -CH2CH2-, -(CH2)4-, -CH=CH-CH2O-, -C2F4-, -CH2CF2-, -CF2CH2-, -CF=CF-, -CH=CF-, -CF=CH-, -CH=CH-, -C≡C- or a single bond, L11 and L 12 each independently represents F, Cl, CF or CHF, preferably H or F, most preferably F, L 13 represents H or CH3, preferably H, and W represents O or S.

[0231] In a preferred embodiment of the invention the LC medium comprises one or more compounds of the formulae III-1 and / or III-2.

[0232] [ka]

[0233] in which the occurring radicals have the same meaning as given above in formula III, preferably R 11 and R 12 are each independently an alkyl, alkenyl or alkoxy group having up to 15 C atoms, more preferably one or both of them denote an alkoxy group, L 11 and L 12 each preferably represents F.

[0234] In another preferred embodiment the LC medium comprises one or more compounds of the formula III-1 which are selected from the group of the compounds of the formulae III-1-1 to III-1-10, preferably of the formula III-1-6:

[0235] [ka]

[0236] [ka]

[0237] In the formula, alkyl and alkyl *each independently represents a linear alkyl group having 1 to 6 carbon atoms, and alkenyl and alkenyl * each independently represents a linear alkenyl group having 2 to 6 carbon atoms, alkoxy and alkoxy * each independently represents a linear alkoxy group having 1 to 6 C atoms, and L 11 and L 12 each independently represents F or Cl, preferably both represent F.

[0238] In another preferred embodiment the LC medium comprises one or more compounds of the formula III-2, preferably of the formula III-2-6, selected from the group of the compounds of the formulae III-2-1 to III-2-11

[0239] [ka]

[0240] [ka]

[0241] In the formula, alkyl and alkyl * each independently represents a linear alkyl group having 1 to 6 carbon atoms, and alkenyl and alkenyl * each independently represents a linear alkenyl group having 2 to 6 carbon atoms, alkoxy and alkoxy * each independently represents a linear alkoxy group having 1 to 6 C atoms, and L 11 and L 12 each independently represents F or Cl, preferably both represent F.

[0242] In another preferred embodiment the LC medium comprises one or more compounds of formula IIIA-1 and / or IIIA-2.

[0243] [ka]

[0244] In the formula, L 11 and L 12 has the same meaning as given in formula III, (O) represents O or a single bond, R IIIA is an alkyl or alkenyl group having up to 7 C atoms or a group Cy-C m H 2m+1 - represents m and n are the same or different and are 0, 1, 2, 3, 4, 5 or 6, preferably 1, 2 or 3, very preferably 1, Cy represents alkyl or alkenyl, each having up to 3 C atoms, or an alicyclic group having 3, 4 or 5 ring atoms, optionally substituted by halogen or CN, and preferably represents cyclopropyl, cyclobutyl or cyclopentyl.

[0245] The compounds of the formulae IIIA-1 and / or IIIA-2 are contained in the LC medium alternatively or additionally, preferably additionally, to the compounds of formula III.

[0246] Highly preferred compounds of formula IIIA-1 and IIIA-2 are:

[0247] [ka]

[0248] In the formula, alkoxy is a straight-chain alkoxy group having 1 to 6 C atoms.

[0249] In a preferred embodiment of the invention the LC medium comprises one or more compounds of formula III-3

[0250] [ka]

[0251] During the ceremony, R 11 , R 12 are the same or different and represent H, an alkyl or alkoxy group having 1 to 15 C atoms, provided that one or more CH groups in these groups are not directly linked to O atoms, and are -C≡C-, -CF2O-, -OCF2-, -CH=CH-, [ka] Each may be replaced independently by -O-, -CO-O- or -O-CO-, in which additionally one or more H atoms may be replaced by halogen.

[0252] The compound of formula III-3 is preferably selected from the group of compounds of formulae III-3-1 to III-3-10.

[0253] [ka]

[0254] [ka]

[0255] In the formula, R 12 stands for alkyl having 1 to 7 C atoms, preferably ethyl, n-propyl or n-butyl, or alternatively cyclopropylmethyl, cyclobutylmethyl or cyclopentylmethyl.

[0256] In another preferred embodiment of the invention the LC medium comprises one or more compounds of the formulae III-4 to III-6, preferably of the formula III-5.

[0257] [ka]

[0258] where the parameters have the meanings given above and R 11preferably represents a linear alkyl group, R 12 preferably denotes alkoxy, each having 1 to 7 C atoms.

[0259] In another preferred embodiment the LC medium comprises one or more compounds of the formula I selected from the group of the compounds of the formulae III-7 to III-9, preferably of the formula III-8.

[0260] [ka]

[0261] where the parameters have the meanings given above and R 11 preferably represents a linear alkyl group, R 12 preferably denotes alkoxy, each having 1 to 7 C atoms.

[0262] In a preferred embodiment, the medium comprises one or more compounds of formula IV.

[0263] [ka]

[0264] During the ceremony, R 41 represents an unsubstituted alkyl group having 1 to 7 C atoms or an unsubstituted alkenyl group having 2 to 7 C atoms, preferably an n-alkyl group, particularly preferably having 2, 3, 4 or 5 C atoms, R 42 represents an unsubstituted alkyl group having 1 to 7 C atoms or an unsubstituted alkoxy group having 1 to 6 C atoms (both of which preferably have 2 to 5 C atoms), an unsubstituted alkenyl group having 2 to 7 C atoms, preferably having 2, 3 or 4 C atoms, more preferably a vinyl group or a 1-propenyl group, in particular a vinyl group.

[0265] The compound of formula IV is preferably selected from the group of compounds of formulae IV-1 to IV-4.

[0266] [ka]

[0267] During the ceremony, alkyl and alkyl' each independently represent an alkyl having 1 to 7 C atoms, preferably having 2 to 5 C atoms, alkenyl represents an alkenyl group having 2 to 5 C atoms, preferably 2 to 4 C atoms, particularly preferably 2 C atoms; alkenyl' represents an alkenyl group having 2 to 5 C atoms, preferably having 2 to 4 C atoms, particularly preferably having 2 to 3 C atoms, Alkoxy represents alkoxy having 1 to 5 C atoms, preferably having 2 to 4 C atoms.

[0268] Preferably the LC medium comprises one or more compounds selected from the compounds of the formulae IV-1-1 to IV-1-4.

[0269] [ka]

[0270] Very preferably, the LC medium according to the invention comprises one or more compounds of the formulae IV-2-1 and / or IV-2-2.

[0271] [ka]

[0272] Very preferably, the LC medium according to the invention comprises a compound of the formula IV-3, in particular selected from the compounds of the formulae IV-3-1 to IV-3-4

[0273] [ka]

[0274] Very preferably, the LC medium according to the invention comprises a compound of the formula IV-4, in particular selected from the compounds of the formulae IV-4-1 and IV-4-2:

[0275] [ka]

[0276] The LC medium preferably additionally comprises one or more compounds of the formula IVa.

[0277] [ka]

[0278] During the ceremony, R 41 and R 42 each independently of one another represents a straight-chain alkyl, alkoxy, alkenyl, alkoxyalkyl or alkoxy group having up to 12 C atoms, and [ka] Z 4 represents a single bond, -CH2CH2-, -CH=CH-, -CF2O-, -OCF2-, -CH2O-, -OCH2-, -COO-, -OCO-, -C2F4-, -C4H8-, or -CF=CF-.

[0279] Preferred compounds of formula IVa are shown below.

[0280] [ka]

[0281] In the formula, alkyl and alkyl * each independently represents a linear alkyl group having 1 to 6 C atoms.

[0282] The LC medium according to the invention preferably comprises at least one compound of the formula IVa-1 and / or of the formula IVa-2.

[0283] The proportion of compounds of formula IVa in the mixture as a whole is preferably at least 5% by weight.

[0284] Preferably the LC medium comprises one or more compounds of the formulae IVb-1 to IVb-3.

[0285] [ka]

[0286] During the ceremony, Alkyl and alkyl * each independently represent a linear alkyl group having 1 to 6 C atoms, and alkenyl and alkenyl * each independently represents a linear alkenyl group having 2 to 6 C atoms.

[0287] The proportion of biphenyls of the formulae IV-1 to IV-3 in the entire mixture is preferably at least 3% by weight, in particular 5% by weight or more.

[0288] Among the compounds of the formulae IVb-1 to IVb-3, the compound of the formula IVb-2 is particularly preferred.

[0289] Particularly preferred are biphenyls.

[0290] [ka]

[0291] In the formula, alkyl * represents an alkyl group having 1 to 6 C atoms, preferably n-propyl.

[0292] The LC media according to the invention particularly preferably comprise one or more compounds of the formulae IVb-1-1 and / or IVb-2-3.

[0293] In a particularly preferred embodiment the LC medium comprises one or more compounds of formula V

[0294] [ka]

[0295] During the ceremony, R 51 and R 52 are independent of each other. 41 and R 42 has one of the meanings given in the formula (I) and preferably denotes alkyl having 1 to 7 C atoms, preferably n-alkyl, particularly preferably n-alkyl having 1 to 5 C atoms, alkoxy having 1 to 7 C atoms, preferably n-alkoxy, particularly preferably n-alkoxy having 2 to 5 C atoms, alkoxyalkyl having 2 to 7 C atoms, preferably 2 to 4 C atoms, alkenyl or alkenyloxy, preferably alkenyloxy, [ka] During the ceremony, [ka] Z 51 , Z 52 each independently represents -CH-CH-, -CH-O-, -CH=CH-, -C≡C-, -COO- or a single bond, preferably -CH-CH-, -CH-O- or a single bond, particularly preferably a single bond, n is 1 or 2.

[0296] The compound of formula V is preferably selected from the compounds of formulae V1 to V16.

[0297] [ka]

[0298] [ka]

[0299] In the formula, R 1 and R 2 R above 2A R 1 and R 2 preferably each independently of one another represents straight-chain alkyl or alkenyl.

[0300] Preferred LC media comprise one or more compounds of formula V-1, V-3, V-4, V-6, V-7, V-10, V-11, V-12, V-14, V-15 and / or V-16

[0301] The LC media according to the invention very particularly preferably comprise compounds of the formulae V-10, V-12, V-16 and / or IV-1, especially in an amount of 5 to 30%.

[0302] Preferred compounds of formula V-10 are shown below.

[0303] [ka]

[0304] The LC media according to the invention particularly preferably comprise tricyclic compounds of the formulae V-10a and / or V-10b in combination with one or more bicyclohexyl compounds of the formula IV-1. The total proportion of compounds of the formulae V-10a and / or V-10b in combination with one or more compounds selected from the bicyclohexyl compounds of the formula IV-1 is 5 to 40%, very particularly preferably 15 to 35%.

[0305] Very particularly preferred LC media comprise the compounds V-10a and IV-1-1.

[0306] [ka]

[0307] The compounds V-10a and IV-1-1 are preferably present in the mixture in a concentration of 15 to 35%, particularly preferably 15 to 25%, particularly preferably 18 to 22%, based on the mixture as a whole.

[0308] Very particularly preferred LC media comprise the compounds V-10b and IV-1-1.

[0309] [ka]

[0310] The compounds V-10b and IV-1-1 are preferably present in the mixture in a concentration of 15 to 35%, particularly preferably 15 to 25%, particularly preferably 18 to 22%, based on the mixture as a whole.

[0311] Very particularly preferred LC media comprise the following three types of compounds:

[0312] [ka]

[0313] The compounds V-10a, V-10b and IV-1-1 are preferably present in the mixture in a concentration of 15 to 35%, particularly preferably 15 to 25%, particularly preferably 18 to 22%, based on the mixture as a whole.

[0314] Preferred LC media comprise at least one compound selected from the group of compounds below.

[0315] [ka]

[0316] In the formula, R 41 and R 42 And R 51and R 52 has the meaning given above. Preferably, in compounds V-6, V-7 and IV-1, R 41 and R 51 represents an alkyl or alkenyl having 1 to 6 or 2 to 6 C atoms, respectively, and R 42 and R 52 represents alkenyl having 2 to 6 C atoms.

[0317] Preferred LC media comprise at least one compound of the formulae V-6a, V-6b, V-7a, V-7b, IV-4-1, IV-4-2, IV-3a and IV-3b.

[0318] [ka]

[0319] In the formula, alkyl represents an alkyl group having 1 to 6 C atoms, and alkenyl represents an alkenyl group having 2 to 6 C atoms.

[0320] The compounds of the formulae V-6a, V-6b, V-7a, V-7b, IV-4-1, IV-4-2, IV-3a and IV-3b are preferably present in the mixtures according to the invention in an amount of 1 to 40% by weight, preferably 5 to 35% by weight and very particularly preferably 10 to 30% by weight.

[0321] In a preferred embodiment of the invention the LC medium additionally comprises one or more compounds of the formulae VI-1 to VI-9.

[0322] [ka]

[0323] [ka]

[0324] During the ceremony, R 7are each independently a group represented by R 2A has one of the meanings given in w and x each independently represent 1 to 6.

[0325] Particular preference is given to LC media which comprise at least one compound of the formula V-9.

[0326] In a preferred embodiment of the invention the LC medium additionally comprises one or more compounds of the formulae VII-1 to VII-25.

[0327] [ka]

[0328] [ka]

[0329] [ka]

[0330] [ka]

[0331] During the ceremony, R represents a linear alkyl or alkoxy group having 1 to 6 C atoms, (O) represents -O- or a single bond, X represents F, Cl, OCF3 or OCHF2, L x represents H or F; m is 0, 1, 2, 3, 4, 5 or 6; and n is 1, 2, 3 or 4.

[0332] R preferably represents methyl, ethyl, propyl, butyl, pentyl, hexyl, methoxy, ethoxy, propoxy, butoxy, pentoxy.

[0333] X preferably represents F or OCH3, very preferably F.

[0334] The LC media according to the invention preferably contain terphenyls of the formulae VII-1 to VII-25 in an amount of 2 to 30% by weight, in particular 5 to 20% by weight.

[0335] Particularly preferred are compounds of formulae VII-1, VII-2, VII-4, VII-20, VII-21 and VII-22, in which X represents F. In these compounds R preferably represents alkyl, furthermore alkoxy, each having 1 to 5 C atoms. In compounds of formula VII-20 R preferably represents alkyl or alkenyl, in particular alkyl. In compounds of formula VII-21 R preferably represents alkyl. In compounds of formulae VII-22 to VII-25 X preferably represents F.

[0336] Terphenyls are preferably employed in the LC media according to the invention, for which the mixture has a Δn value of 0.1 or more. Preferred LC media contain 2-20% by weight of one or more terphenyl compounds selected from the group of compounds VII-1 to VII-25.

[0337] Further preferred embodiments are listed below.

[0338] a) LC medium comprising at least one compound of the formulae Z-1 to Z-7.

[0339] [ka]

[0340] wherein R, (O) and alkyl have the meanings given above in formula III.

[0341] b) Preferred LC media according to the invention comprise one or more substances which contain a tetrahydronaphthyl or naphthyl unit, such as, for example, the compounds of the formulae N-1 to N-5.

[0342] [ka]

[0343] R in the formula 1N and R 2N are each independently R 2A and preferably represents straight-chain alkyl, straight-chain alkoxy or straight-chain alkenyl, Z 1 and Z 2 each independently represents -C2H4-, -CH=CH-, -(CH2)4-, -(CH2)3O-, -O(CH2)3-, -CH=CHCH2CH2-, -CH2CH2CH=CH-, -CHO-, -OCH2-, -COO-, -OCO-, -C2F4-, -CF=CF-, -CF=CH-, -CH=CF-, -CF2O-, -OCF2-, -CH2- or a single bond.

[0344] c) Preferred LC media comprise one or more compounds selected from the group of the difluorodibenzochroman compounds of formula BC, the chromans of formula CR, the fluorinated phenanthrenes of formula PH-1 and PH-2.

[0345] [ka]

[0346] During the ceremony, R B1 , R B2 , R CR1 , R CR2 , R 1 , R 2 are each independently R 2A c is 0, 1 or 2. 1 and R 2 preferably each independently denote alkyl or alkoxy having 1 to 6 C atoms.

[0347] The LC media according to the invention preferably comprise compounds of the formulae BC, CR, PH-1, PH-2 in an amount of 3 to 20% by weight, in particular in an amount of 3 to 15% by weight.

[0348] Particularly preferred compounds of formulae BC and CR are compounds BC-1 to BC-7 and CR-1 to CR-5.

[0349] [ka]

[0350] [ka]

[0351] During the ceremony, Alkyl and alkyl * each independently represents a linear alkyl group having 1 to 6 C atoms, alkenyl and alkenyl * each independently represents a linear alkenyl group having 2 to 6 C atoms.

[0352] Very particular preference is given to LC media which comprise one, two or three compounds of the formulae BC-2, BF-1 and / or BF-2.

[0353] d) Preferred LC media comprise one or more indane compounds of the formula In.

[0354] [ka]

[0355] During the ceremony, R 11 , R 12 , R 13 each independently represents a linear alkyl, alkoxy, alkoxyalkyl or alkenyl group having 1 to 6 C atoms, R 12 and R 13 represents an additional halogen, preferably F, [ka] represents i represents 0, 1 or 2.

[0356] Preferred compounds of formula In are compounds of formulae In-1 to In-16 shown below.

[0357] [ka]

[0358] [ka]

[0359] [ka]

[0360] Particularly preferred are the compounds of formulae In-1, In-2, In-3 and In-4.

[0361] The compounds of the formula In and the subformulae In-1 to In-16 are preferably employed in the LC media according to the invention in a concentration of more than 5% by weight, in particular 5 to 30% by weight, very particularly preferably 5 to 25% by weight.

[0362] e) Preferred LC media additionally comprise one or more compounds of the formulae L-1 to L-5.

[0363] [ka]

[0364] [ka]

[0365] During the ceremony, R and R 1 are each independently R in formula IIA above. 2Awhere alkyl represents an alkyl group having 1 to 6 C atoms. The parameter s represents 1 or 2.

[0366] The compounds of the formulae L1 to L5 are preferably used in concentrations of 5 to 50% by weight, in particular 5 to 40% by weight, very particularly preferably 10 to 40% by weight.

[0367] f) Preferred LC media additionally comprise one or more compounds of the formulae IIA-Y.

[0368] [ka]

[0369] R in the formula 11 and R 12 is R in the above formula IIA 2A has one of the meanings given to L 1 and L 2 are the same or different and represent F or Cl.

[0370] Preferred compounds of formula IIA-Y are selected from the group consisting of the following subformulae:

[0371] [ka]

[0372] [ka]

[0373] In the formula, Alkyl and Alkyl * each independently represents a linear alkyl group having 1 to 6 C atoms, Alkoxy represents a linear alkoxy group having 1 to 6 C atoms, Alkenyl and Alkenyl * each independently represents a linear alkenyl group having 2 to 6 C atoms, and O represents an oxygen atom or a single bond. Alkenyl and Alkenyl *preferably represents CH2=CH-, CH2=CHCH2CH2-, CH3-CH=CH-, CH3-CH2-CH=CH-, CH3-(CH2)2-CH=CH-, CH3-(CH2)3-CH=CH- or CH3-CH=CH-(CH2)2-.

[0374] Particularly preferred compounds of formula IIA-Y are selected from the group consisting of the following subformulae:

[0375] [ka]

[0376] In the formula, Alkoxy and Alkoxy * has the meaning defined above and preferably denotes methoxy, ethoxy, n-propyloxy, n-butyloxy or n-pentyloxy.

[0377] g) LC medium additionally comprising one or more quaterphenyl compounds selected from the following formulae:

[0378] [ka]

[0379] During the ceremony, R Q is alkyl, alkoxy, oxaalkyl or alkoxyalkyl having 1 to 9 C atoms or alkenyl or alkenyloxy having 2 to 9 C atoms, all of which may be fluorinated, X Q is F, Cl, a halogenated alkyl or alkoxy having 1 to 6 C atoms or a halogenated alkenyl or alkenyloxy having 2 to 6 C atoms, L Q1 ~L Q6 are each independently H or F, with the proviso that L Q1 ~L Q6 At least one of is F.

[0380] Preferred compounds of formula Q are Q is straight-chain alkyl having 2 to 6 C atoms, very preferably ethyl, n-propyl or n-butyl.

[0381] Preferred compounds of formula Q are Q3 and L Q4 is F.

[0382] Further preferred compounds of formula Q are Q3 , L Q4 And L Q1 and L Q2 One or two of the following are F:

[0383] Preferred compounds of formula Q are Q represents F or OCF3, very preferably F.

[0384] The compounds of formula Q are preferably selected from the following sub-formulae:

[0385] [ka]

[0386] In the formula, R Q has one of the meanings of formula Q or one of the preferred meanings given above and below, preferably ethyl, n-propyl or n-butyl.

[0387] Especially R Q Particularly preferred are compounds of formula Q1, wherein is n-propyl.

[0388] Preferably the proportion of compound of formula Q in the LC host mixture is from >0 to 5% by weight, very preferably from 0.05 to 2% by weight, more preferably from 0.1 to 1% by weight, most preferably from 0.1 to 0.8% by weight.

[0389] Preferably the LC medium comprises 1 to 5, preferably 1 or 2, compounds of formula Q.

[0390] The addition of quaterphenyl compounds of formula Q to the LC host mixture can reduce ODF mura while maintaining high UV absorptivity, allowing fast and complete polymerization, enabling strong and fast tilt angle generation, and enhancing the UV stability of the LC medium.

[0391] In addition, the compound of formula Q with positive dielectric anisotropy can be added to an LC medium with negative dielectric anisotropy to obtain a dielectric constant ε ∥ and ε ⊥ In particular, the dielectric constant ε can be controlled by changing the dielectric anisotropy Δε. ∥ It is then possible to achieve high values ​​of V 2 , thereby reducing kickback voltage and reducing image sticking.

[0392] The LC medium according to the invention preferably has

[0393] one or more compounds of formula M, preferably selected from formulae M1 to M33, preferably at a total concentration in the range of 0.01% to 2.0%, more preferably 0.1% to 1.0%, most preferably 0.2% to 0.8%,

[0394] and / or one or more compounds of formula IIA, preferably in a total concentration in the range of 5% to 30%, more preferably 7% to 25%, particularly preferably 10% to 20%;

[0395] and / or one or more compounds of formulae IIA and IIB, preferably in a total concentration in the range of 30% to 45%;

[0396] and / or one or more compounds of formula IV, preferably in a total concentration in the range of 35% to 70%, more preferably 40% to 65%, particularly preferably 45% to 60%;

[0397] and / or one or more compounds of formula IV-3, preferably in a total concentration in the range of 35% to 60%, more preferably 40% to 55%, particularly preferably 45% to 50%;

[0398] and / or one or more compounds of formula III-2, preferably of formula III-2-6, preferably in a total concentration ranging from 2% to 25%, more preferably from 5% to 15%, particularly preferably from 5% to 12%. Includes.

[0399] In particular, the media

[0400] one or more compounds CY-n-Om, in particular CY-3-O4, CY-5-O4 and / or CY-3-O2, preferably in a total concentration in the range of 5% to 30%, preferably 10% to 20%;

[0401] and / or one or more compounds PY-n-Om, in particular PY-3-O2 and / or PY-1-O2, preferably in a total concentration in the range of 5% to 30%, preferably 5% to 20%;

[0402] and / or CPY-n-Om, in particular CPY-2-O2, CPY-3-O2 and / or CPY-5-O2, preferably in a concentration of more than 5%, in particular 7% to 20%, based on the total mixture;

[0403] and / or one or more compounds CCY-n-Om, preferably CCY-4-O2, CCY-3-O2, CCY-3-O3, CCY-3-O1 and / or CCY-5-O2, preferably in a concentration of more than 3%, in particular 5-15%, based on the entire mixture;

[0404] and / or one or more compounds CPY-n-Om, preferably CPY-2-O2 and / or CPY-3-O2, preferably in a concentration of more than 3%, in particular 5-15%, based on the total mixture;

[0405] and / or CLY-n-Om, preferably CLY-2-O4, CLY-3-O2 and / or CLY-3-O3, preferably in a concentration of more than 5%, in particular 10-30%, very preferably 15-20%, based on the total mixture;

[0406] and / or CPY-n-Om and CY-n-Om, preferably at a concentration of 10-80% based on the total mixture;

[0407] and / or CPY-n-Om and PY-n-Om, preferably CPY-2-O2 and / or CPY-3-O2 and PY-3-O2 or PY-1-O2, preferably in a concentration of 5 to 20%, more preferably 10 to 15%, based on the total mixture,

[0408] and / or CC-3-V, preferably at a concentration of 5-50% based on the total mixture;

[0409] and / or the compounds CC-3-V1 and / or CC-4-V1 in a total concentration ranging from 5% to 40%, more preferably from 15% to 35%, particularly preferably from 20% to 30%,

[0410] and / or one or more compounds of the formulae B-nO-Om and / or B(S)-nO-Om, in particular the compounds B(S)-2O-O4 and / or B(S)-2O-O5, preferably in a concentration in the range from 2 to 12%,

[0411] and / or 0.1%~3% compound PPGU-3-F Includes.

[0412] Advantageously, the LC media according to the invention have a nematic phase preferably between -20°C and 70°C, particularly preferably between -30°C and 80°C and very particularly preferably between -40°C and 90°C.

[0413] The medium according to the invention has a clearing temperature of 70°C or more, preferably 74°C or more.

[0414] The expression "having a nematic phase" in this document means, on the one hand, that neither smectic phases nor crystallization are observed at the corresponding low temperatures, and, on the other hand, that on heating from the nematic phase, clearing does not yet occur. The investigations at low temperatures are carried out in a flow viscometer at the corresponding temperature and are confirmed by storage for at least 100 hours in test cells with layer thicknesses corresponding to the electro-optical application. If the storage stability of the corresponding test cells at a temperature of -20°C is 1000 hours or more, the medium is considered stable at this temperature. At temperatures of -30°C and -40°C, the corresponding times are 500 hours and 250 hours, respectively. At high temperatures, the clearing point is measured by conventional methods in capillaries.

[0415] The liquid crystal mixture preferably has a nematic phase range of at least 60K and a maximum melting point of 30mm at 20°C. 2 ·s -1 Flow viscosity ν 20 has.

[0416] The mixture is nematic at temperatures below -20°C, preferably below -30°C, very preferably below -40°C.

[0417] The birefringence value Δn of the liquid crystal mixture is generally between 0.07 and 0.16, preferably between 0.08 and 0.15, very preferably between 0.09 and 0.14.

[0418] In a preferred embodiment of the invention, the medium has a birefringence in the range of 0.090 to 0.110, preferably 0.095 to 0.105, in particular 0.100 to 0.105.

[0419] In another preferred embodiment, the medium according to the present invention has a birefringence of 0.120 or more, preferably within the range of 0.125 to 0.145, more preferably 0.130 to 0.140.

[0420] The liquid crystal mixture according to the invention has a dielectric anisotropy Δε of −1.5 to −8.0, preferably of −2.0 to −4.0, in particular of −2.5 to −3.5.

[0421] The rotational viscosity γ1 at 20° C. is preferably 120 mPa·s or less, particularly preferably 100 mPa·s or less.

[0422] In a preferred embodiment, the rotational viscosity γ1 at 20° C. is 100 mPa·s or less, particularly 95 mPa·s or less.

[0423] The liquid-crystalline media according to the invention have relatively low values ​​of the threshold voltage (V0). They are preferably in the range from 1.7 V to 3.0 V, particularly preferably below 2.7 V and very particularly preferably below 2.5 V.

[0424] For the present invention, the term "threshold voltage" relates to the capacitive threshold (V0), also called the Freedericks threshold, unless otherwise stated.

[0425] In addition, the liquid-crystal media according to the invention have high values ​​for the voltage holding ratio in a liquid-crystal cell.

[0426] In general, liquid crystal media having a low addressing voltage or threshold voltage show a lower voltage holding ratio than those having a high addressing voltage or threshold voltage, and vice versa.

[0427] In the present invention, the term "dielectrically positive compounds" denotes compounds with Δε>1.5, the term "dielectrically neutral compounds" denotes those with -1.5≦Δε≦1.5 and the term "dielectrically negative compounds" denotes those with Δε<-1.5. The dielectric anisotropy of the compounds is determined here by dissolving 10% of the compounds in an LC host and the capacitance of the resulting mixtures in at least one test cell with a layer thickness of in each case 20 μm and with homeotropic and homogeneous surface alignment at 1 kHz. The measuring voltage is typically between 0.5 V and 1.0 V, but always below the capacitance threshold of each liquid crystal mixture considered.

[0428] All temperature values ​​given for this invention are in °C.

[0429] The LC media according to the invention are suitable for all VA-TFT (vertical alignment-thin film transistor) applications, for example VAN (vertically aligned nematic), MVA (multidomain VA), (S)-PVA (super patterned VA), ASV (advanced super view or axially symmetric VA), PSA (polymer sustained VA) and PS-VA (polymer stabilized VA). They are furthermore suitable for IPS (in-plane switching) and FFS (fringe field switching) applications with negative Δε.

[0430] The nematic LC medium in the displays according to the invention generally comprises two components A1 and A2 which themselves consist of one or more individual compounds.

[0431] Component A1 has a significantly negative dielectric anisotropy and gives the nematic phase a dielectric anisotropy Δε of less than or equal to −0.5. It preferably comprises compounds of the formulae IIA, IIB and / or IIC and further one or more compounds of the formula IV-1.

[0432] The proportion of component A1 is preferably between 45 and 100%, in particular between 60 and 85%.

[0433] For component A1, one (or more) individual compounds are preferably selected that have a Δε value of less than or equal to −0.8, this value having to be more negative the smaller the proportion of component A in the overall mixture.

[0434] Component A2 has a pronounced nematogenicity and a 30 mm 2 ·s -1 Less than 25mm, preferably 2 ·s -1 It has the following flow viscosity:

[0435] A large number of suitable materials are known to the skilled artisan from the literature. Particularly preferred is the compound of formula O-17.

[0436] Particularly preferred individual compounds of component A2 have a viscosity of 18 mmHg at 20° C. 2 ·s -1 Less than 12mm, preferably 2 ·s -1 It is a very low viscosity nematic liquid crystal having the following flow viscosity:

[0437] Component A2 is unidirectionally or enantiomerically nematic, has no smectic phases and is capable of preventing the occurrence of smectic phases in LC media up to very low temperatures. For example, when various highly nematogenic materials are added to a smectic liquid crystal mixture, the nematogenicity of these materials can be compared through the degree of smectic phase suppression achieved.

[0438] The mixture may also contain a component A3 which comprises compounds having a dielectric anisotropy of Δε≧1.5. These so-called positive compounds are generally present in mixtures of negative dielectric anisotropy in amounts of up to 20% by weight, based on the entire mixture.

[0439] The LC medium preferably comprises 4 to 15, in particular 5 to 12, particularly preferably less than 10 compounds of the formulae IIA, IIB and / or IIC and optionally one or more compounds of the formula IV-1.

[0440] Besides the compounds of formula IIA, IIB and / or IIC and optionally IV-1, other components may also be present, for example in amounts of up to 45%, preferably up to 35%, in particular up to 10% of the total mixture.

[0441] The further components are preferably selected from nematic or nematogenic substances, in particular from the known substances, from the classes of azoxybenzenes, benzylideneanilines, biphenyls, terphenyls, phenyl or cyclohexylbenzoates, phenyl or cyclohexylcyclohexanecarboxylates, phenylcyclohexanes, cyclohexylbiphenyls, cyclohexylcyclohexanes, cyclohexylnaphthalenes, 1,4-biscyclohexylbiphenyls or cyclohexylpyrimidines, phenyl or cyclohexyldioxanes, optionally halogenated stilbenes, benzyl phenyl ethers, tolanes and substituted cinnamates.

[0442] The most important compounds suitable as components of this type of liquid crystal phase can be characterized by the formula OC.

[0443] [ka]

[0444] in which L and E each represent a carbocyclic or heterocyclic ring system from the group formed by 1,4-disubstituted benzene and cyclohexane rings, 4,4'-disubstituted biphenyl, phenylcyclohexane and cyclohexylcyclohexane systems, 2,5-disubstituted pyrimidine and 1,3-dioxane rings, 2,6-disubstituted naphthalenes, di- and tetrahydronaphthalenes, quinazolines and tetrahydroquinazolines, G is -CH=CH-, -N(O)=N-, -CH=CQ-, -CH=N(O)-, -C≡C-, -CH2-CH2-, -CO-O-, -CH2-O-, -CO-S-, -C Represents H2-S-, -CH=N-, -COO-Phe-COO-, -CF2O-, -CF=CF-, -OCF2-, -OCH2-, -(CH2)4-, -(CH2)3O-, or a CC single bond, Q represents a halogen, preferably chlorine, or represents -CN, and R 20 and R 21 represents alkyl, alkenyl, alkoxy, alkoxyalkyl or alkoxycarbonyloxy, each having up to 18, preferably up to 8, carbon atoms, or one of these groups represents CN, NC, NO2, NCS, CF3, SF5, OCF3, F, Cl, or Br.

[0445] In most of these compounds, R 20 and R 21 are different from each other, one of these groups is usually an alkyl or alkoxy group. Other variations of the proposed substituents are also common. Many such substances or mixtures thereof are commercially available. All these substances can be prepared by methods known from the literature.

[0446] It will be appreciated by those skilled in the art that the VA, IPS or FFS mixtures according to the invention may also comprise compounds in which, for example, H, N, O, Cl and F are replaced by the corresponding isotopes.

[0447] The combination of the compounds of the above-mentioned preferred embodiments with the above-mentioned polymerizable compounds results in low threshold voltages, low rotational viscosities and very good low-temperature stability in the LC media according to the invention, while always having high clearing points and high HR values, making it possible to rapidly establish particularly low tilt angles (i.e. large tilts) in PSA displays.In particular, the LC media also show significantly reduced response times, especially gray-scale response times, in PSA displays compared to LC media according to the prior art.

[0448] The LC media according to the invention may also comprise further additives selected without limitation from the following list: antioxidants, free radical scavengers, surfactants, antifoaming agents, wetting agents, lubricants, dispersants, hydrophobizing agents, adhesives, flow improvers, degassing agents, diluents, reactive diluents, adjuvants, colorants, dyes, pigments and nanoparticles.

[0449] The individual components of the above-listed preferred embodiments of the LC media according to the invention are known or based on standard methods described in the literature, so that the preparation methods thereof can be easily derived by those skilled in the art from the prior art.Compounds corresponding to formula CY are described, for example, in EP-A-0 364 538.Compounds corresponding to formula ZK are described, for example, in DE-A-26 36 684 and DE-A-33 21 373.

[0450] The LC media that can be used according to the present invention are prepared in a manner conventional per se, for example by mixing one or more of the compounds described above with one or more polymerizable compounds as defined above, and optionally with further liquid crystal compounds and / or additives.In general, the desired amount of the component that is used in a smaller amount is dissolved in the component that constitutes the main component, advantageously at high temperature.It is also possible to mix solutions of the components in an organic solvent, for example acetone, chloroform or methanol, and, after thorough mixing, remove the solvent again, for example by distillation.The present invention further relates to a method for producing the LC media according to the present invention.

[0451] It will be appreciated by those skilled in the art that the LC media according to the invention may also comprise compounds in which, for example, H, N, O, Cl, F are replaced by the corresponding isotopes, such as deuterium.

[0452] Above and below, [ka] represents a trans-1,4-cyclohexylene ring, [ka] represents a 1,4-phenylene ring.

[0453] Above and below, "organic group" represents a carbon or hydrocarbon group.

[0454] The term "carbon group" refers to a monovalent or polyvalent organic group containing at least one carbon atom, provided that it either does not contain any additional type of atom (e.g., -C≡C-, etc.) or it may contain one or more additional types of atoms, such as, for example, N, O, S, B, P, Si, Se, As, Te, or Ge (e.g., carbonyl, etc.). The term "hydrocarbon group" refers to a carbon group that additionally contains one or more H atoms and may contain one or more heteroatoms, such as, for example, N, O, S, B, P, Si, Se, As, Te, or Ge.

[0455] "Halogen" represents F, Cl, Br or I.

[0456] -CO-, -C(=O)- and -C(O)- are carbonyl groups, i.e. [ka] Represents.

[0457] The carbon or hydrocarbon group may be saturated or unsaturated. The unsaturated group may be, for example, an aryl, alkenyl or alkynyl group. The carbon or hydrocarbon group having more than three C atoms may be linear, branched and / or cyclic, and may contain spiro-linked or fused rings.

[0458] The terms "alkyl," "aryl," "heteroaryl," etc. also include polyvalent radicals, such as alkylene, arylene, heteroarylene, etc.

[0459] The term "aryl" refers to an aromatic carbon group or a group derived therefrom. The term "heteroaryl" refers to an "aryl" as defined above containing one or more heteroatoms, preferably selected from N, O, S, Se, Te, Si and Ge.

[0460] Preferred carbon and hydrocarbon groups are optionally substituted and linear, branched or cyclic alkyl, alkenyl, alkynyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy and alkoxycarbonyloxy having 1 to 40, preferably 1 to 20 and very preferably 1 to 12 C atoms, aryl or aryloxy, optionally substituted and having 5 to 30, preferably 6 to 25 C atoms, or alkylaryl, arylalkyl, alkylaryloxy, arylalkyloxy, arylcarbonyl, aryloxycarbonyl, arylcarbonyloxy and aryloxycarbonyloxy, optionally substituted and having 5 to 30, preferably 6 to 25 C atoms, whereby one or more C atoms may be replaced by a heteroatom, preferably selected from N, O, S, Se, Te, Si and Ge.

[0461] More preferred carbon and hydrocarbon groups are C1-C 20 Alkyl, C2-C 20 Alkenyl, C2-C 20 Alkynyl, C3-C 20 Allyl, C4~C 20Alkyldienyl, C4-C 20 Polyenyl, C6-C 20 Cycloalkyl, C4-C 15 Cycloalkenyl, C6-C 30 Aryl, C6-C 30 Alkylaryl, C6-C 30 Aryl alkyl, C6-C 30 Alkylaryloxy, C6-C 30 Arylalkyloxy, C2-C 30 Heteroaryl, C2-C 30 It is heteroaryloxy.

[0462] C1~C 12 Alkyl, C2-C 12 Alkenyl, C2-C 12 Alkynyl, C6-C 25 Aryl and C2-C 25 Heteroaryl is especially preferred.

[0463] Further preferred carbon and hydrocarbon groups are alkyl, linear, branched or cyclic, having 1 to 20, preferably 1 to 12, C atoms, which are unsubstituted or mono- or polysubstituted by F, Cl, Br, I or CN, with the proviso that one or more non-adjacent CH groups are each independently of one another -C(R x )=C(R x )-, -C≡C-, -N(R x ) -, -O-, -S-, -CO-, -CO-O-, -O-CO-, or -O-CO-O-.

[0464] R xpreferably represents H, F, Cl, CN, a linear, branched or cyclic alkyl chain having 1 to 25 C atoms (with the proviso that in addition, one or more non-adjacent C atoms may be replaced by -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O-, with the proviso that one or more H atoms may be replaced by F or Cl), or an optionally substituted aryl or aryloxy group having 6 to 30 C atoms, or an optionally substituted heteroaryl or heteroaryloxy group having 2 to 30 C atoms.

[0465] Preferred alkyl groups are, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, s-butyl, t-butyl, 2-methylbutyl, n-pentyl, s-pentyl, cyclopentyl, n-hexyl, cyclohexyl, 2-ethylhexyl, n-heptyl, cycloheptyl, n-octyl, cyclooctyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, dodecanyl, trifluoromethyl, perfluoro-n-butyl, 2,2,2-trifluoroethyl, perfluorooctyl, perfluorohexyl, and the like.

[0466] Preferred alkenyl groups are, for example, ethenyl, propenyl, butenyl, pentenyl, cyclopentenyl, hexenyl, cyclohexenyl, heptenyl, cycloheptenyl, octenyl, cyclooctenyl, and the like.

[0467] Preferred alkynyl groups are, for example, ethynyl, propynyl, butynyl, pentynyl, hexynyl, octynyl and the like.

[0468] Preferred alkoxy groups are, for example, methoxy, ethoxy, 2-methoxyethoxy, n-propoxy, i-propoxy, n-butoxy, i-butoxy, s-butoxy, t-butoxy, 2-methylbutoxy, n-pentoxy, n-hexoxy, n-heptoxy, n-octoxy, n-nonoxy, n-decoxy, n-undecoxy, n-dodecoxy, and the like.

[0469] Preferred amino groups are, for example, dimethylamino, methylamino, methylphenylamino, phenylamino, and the like.

[0470] Aryl and heteroaryl groups may be monocyclic or polycyclic, i.e., they may contain one ring (such as phenyl) or two or more rings, and the groups may be fused (such as naphthyl) or covalently linked (such as biphenyl) or may contain a combination of fused and linked rings. Heteroaryl groups preferably contain one or more heteroatoms selected from O, N, S and Se.

[0471] Particularly preferred are monocyclic, bicyclic or tricyclic aryl groups having 6 to 25 C atoms and monocyclic, bicyclic or tricyclic heteroaryl groups having 5 to 25 ring atoms, which may contain fused rings and may be substituted.Furthermore, 5-, 6- or 7-membered aryl and heteroaryl groups are preferred, provided that in addition, one or more CH groups may be replaced by N, S or O, in such a way that the O and / or S atoms are not directly linked to one another.

[0472] Preferred aryl groups are, for example, phenyl, biphenyl, terphenyl, [1,1':3',1"]terphenyl-2'-yl, naphthyl, anthracene, binaphthyl, phenanthrene, 9,10-dihydrophenanthrene, pyrene, dihydropyrene, chrysene, perylene, tetracene, pentacene, benzopyrene, fluorene, indene, indenofluorene, spirobifluorene, and the like.

[0473] Preferred heteroaryl groups are, for example, 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- Five-membered rings such as thiadiazole, 1,2,5-thiadiazole, and 1,3,4-thiadiazole; six-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, and 1,2,3,5-tetrazine; or indole, isoindole, indolizine, indazole, benzimidazole, benzotriazole, pristine, , naphthaimidazole, phenanthroimidazole, pyridaimidazole, pyrazineimidazole, quinoxalineimidazole, benzoxazole, naphthoxazole, anthroxazole, phenanthroxazole, isoxazole, benzothiazole, benzofuran, isobenzofuran, dibenzofuran, quinoline, isoquinoline, pteridine, benzo-5,6-quinoline, benzo-6,7-quinoline, benzo-7,8-quinoline, benzoi These include fused groups such as isoquinoline, acridine, phenothiazine, phenoxazine, benzopyridazine, benzopyrimidine, quinoxaline, phenazine, naphthyridine, azacarbazole, benzocarboline, phenanthridine, phenanthroline, thieno[2,3b]thiophene, thieno[3,2b]thiophene, dithienothiophene, isobenzothiophene, dibenzothiophene, benzothiadiazothiophene, or combinations of these groups.

[0474] The aryl and heteroaryl groups mentioned above and below may also be substituted with alkyl, alkoxy, thioalkyl, fluorine, fluoroalkyl or further aryl or heteroaryl groups.

[0475] (Non-aromatic) alicyclic and heterocyclic groups include both saturated rings, i.e. those containing exclusively single bonds, and also partially unsaturated rings, i.e. those which may also contain multiple bonds. Heterocyclic rings preferably contain one or more heteroatoms selected from Si, O, N, S and Se.

[0476] (Non-aromatic) alicyclic and heterocyclic groups may be monocyclic, i.e. containing only one ring (e.g. cyclohexane) or polycyclic, i.e. containing several rings (e.g. decahydronaphthalene or bicyclooctane). Saturated groups are particularly preferred. Furthermore, monocyclic, bicyclic or tricyclic groups having 5 to 25 ring atoms are preferred, which may contain fused rings and may be substituted. Furthermore, 5-, 6-, 7- or 8-membered carbocyclic groups are preferred, provided that 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 CH2 groups may be replaced by -O- and / or -S-.

[0477] Preferred alicyclic and heterocyclic groups are, for example, 5-membered groups such as cyclopentane, tetrahydrofuran, tetrahydrothiofuran, pyrrolidine, 6-membered groups such as cyclohexane, silinane, cyclohexene, tetrahydropyran, tetrahydrothiopyran, 1,3-dioxane, 1,3-dithiane, piperidine, 7-membered groups such as cycloheptane, and fused groups such as tetrahydronaphthalene, decahydronaphthalene, indane, bicyclo[1.1.1]pentane-1,3-diyl, bicyclo[2.2.2]octane-1,4-diyl, spiro[3.3]heptane-2,6-diyl, octahydro-4,7-methanoindan-2,5-diyl.

[0478] Preferred substituents are solubility-promoting groups such as, for example, alkyl or alkoxy, electron-withdrawing groups such as fluorine, nitro or nitrile, or substituents for increasing the glass transition temperature (Tg) in the polymer, especially bulky groups such as, for example, t-butyl or optionally substituted aryl groups.

[0479] Preferred substituents, hereinafter also referred to as "L", are F, Cl, Br, I, -CN, -NO2, -NCO, -NCS, -OCN, -SCN, -C(=O)N(R x )2, -C(=O)Y 1 , -C(=O)R x , -N(R x )2, linear or branched alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy each having 1 to 25 C atoms (wherein one or more H atoms may be replaced by F or Cl), optionally substituted silyl having 1 to 20 Si atoms, or optionally substituted aryl having 6 to 25, preferably 6 to 15, C atoms.

[0480] In the formula, R x represents H, F, Cl, CN, a linear, branched or cyclic alkyl chain having 1 to 25 C atoms, with the proviso that one or more non-adjacent CH2 groups may be 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 linked to one another, with the proviso that one or more H atoms may be replaced by F, Cl, P- or P-Sp-, respectively, and

[0481] Y 1 represents a halogen.

[0482] The "substituted silyl or aryl" is preferably a halogen, -CN, R 0 , -OR 0 , -CO-R 0 , -CO-OR 0 , -O-CO-R 0 OR-O-CO-OR0 where R 0 represents H or alkyl having 1 to 20 C atoms.

[0483] Particularly preferred substituents L are, for example, F, Cl, CN, NO2, CH3, C2H5, OCH3, OC2H5, COCH3, COC2H5, COOCH3, COOC2H5, CF3, OCF3, OCHF2, OC2F5, and also phenyl.

[0484] [ka] In the formula, L has one of the meanings given above.

[0485] The polymerizable group P is a group suitable for polymerization reactions, such as, for example, free-radical or ionic chain polymerization, polyaddition or polycondensation, or for polymer-analogous reactions, such as, for example, addition or condensation onto a polymer backbone. Groups for chain polymerization, especially those containing a C=C double bond or a C≡C triple bond, and also groups suitable for ring-opening polymerization, such as, for example, oxetane or epoxide groups, are particularly preferred.

[0486] The preferred group P is CH2=CW 1 -CO-O-, CH2=CW 1 -CO-, [ka] CH2=CW 2 -(O) k3 -, C.W. 1 =CH-CO-(O) k3 -, C.W. 1 =CH-CO-NH-, CH2=CW 1 -CO-NH-, CH3-CH=CH-O-, (CH2=CH)2CH-OCO-, (CH2=CH-CH2)2CH-OCO-, (CH2=CH)2CH-O-, (CH2=CH-CH2)2N-, (CH2=CH-CH2)2N-CO-, HO-CW 2 W 3 -, HS-CW 2 W3 -, H.W. 2 N-, HO-CW 2 W 3 -NH-, CH2=CW 1 -CO-NH-, CH2=CH-(COO) k1 -Phe-(O) k2 -, CH2=CH-(CO) k1 -Phe-(O) k2 -, Phe-CH=CH-, HOOC-, OCN- and W 4 W 5 W 6 Si-, wherein W 1 stands for H, F, Cl, CN, CF3, phenyl or alkyl having 1 to 5 C atoms, in particular H, F, Cl or CH3, W 2 and W 3 each independently of one another denotes H or alkyl having 1 to 5 C atoms, in particular H, methyl, ethyl or n-propyl, W 4 , W 5 and W 6 each independently represents Cl, oxaalkyl or oxacarbonylalkyl having 1 to 5 C atoms, W 7 and W 8 each independently of one another represents H, Cl or an alkyl having 1 to 5 C atoms, Phe represents 1,4-phenylene which may be substituted with one or more groups L as defined above other than P-Sp-, k1, k2 and k3 each independently of one another represent 0 or 1, k3 preferably represents 1 and k4 represents an integer from 1 to 10.

[0487] Highly preferred groups P are CH2=CW 1 -CO-O-, CH2=CW 1 -CO-, [ka] CH2=CW 2 -O-, CH2=CW 2 -, C.W. 1 =CH-CO-(O) k3 -, C.W. 1=CH-CO-NH-, CH2=CW 1 -CO-NH-, (CH2=CH)2CH-OCO-, (CH2=CH-CH2)2CH-OCO-, (CH2=CH)2CH-O-, (CH2=CH-CH2)2N-, (CH2=CH-CH2)2N-CO-, CH2=CW 1 -CO-NH-, CH2=CH-(COO) k1 -Phe-(O) k2 -, CH2=CH-(CO) k1 -Phe-(O) k2 -, Phe-CH=CH- and W 4 W 5 W 6 Si-, wherein W 1 stands for H, F, Cl, CN, CF3, phenyl or alkyl having 1 to 5 C atoms, in particular H, F, Cl or CH3, W 2 and W 3 each independently of one another denotes H or alkyl having 1 to 5 C atoms, in particular H, methyl, ethyl or n-propyl, W 4 , W 5 and W 6 each independently represents Cl, oxaalkyl or oxacarbonylalkyl having 1 to 5 C atoms, W 7 and W 8 each independently represents H, Cl or an alkyl having 1 to 5 C atoms; Phe represents 1,4-phenylene; k1, k2 and k3 each independently represent 0 or 1, k3 preferably represents 1, and k4 represents an integer of 1 to 10.

[0488] Very particularly preferred groups P are CH2=CW 1 -CO-O-, in particular CH2=CH-CO-O-, CH2=C(CH3)-CO-O- and CH2=CF-CO-O-, further CH2=CH-O-, (CH2=CH)2CH-O-CO-, (CH2=CH)2CH-O-, [ka] is selected from the group consisting of:

[0489] More preferably the polymerizable group P is selected from the group consisting of vinyloxy, acrylate, methacrylate, fluoroacrylate, chloroacrylate, oxetane and epoxide groups, most preferably from acrylate and methacrylate.

[0490] When Sp is different from a single bond, it is preferably of the formula Sp″-X″, such that each group P-Sp- corresponds to the formula R-Sp″-X″-, with the proviso that

[0491] Sp" represents an alkylene having 1 to 20, preferably 1 to 12, C atoms, which may be mono- or polysubstituted by F, Cl, Br, I or CN, provided that in addition, one or more non-adjacent CH groups are each independently -O-, -S-, -NH-, -N(R 0 )-, -Si(R 0 R 00 )-, -CO-, -CO-O-, -O-CO-, -O-CO-O-, -S-CO-, -CO-S-, -N(R 00 )-CO-O-, -O-CO-N(R 0 )-, -N(R 0 )-CO-N(R 00 )-, -CH=CH- or -C≡C-, “X” is -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O-, -CO-N(R 0 )-, -N(R 0 )-CO-, -N(R 0 )-CO-N(R 00 )-, -OCH2-, -CH2O-, -SCH2-, -CH2S-, -CF2O-, -OCF2-, -CF2S-, -SCF2-, -CF2CH2-, -CH2CF2-, -CF2CF2-, -CH=N-, -N=CH-, -N=N-, -CH=CR 0 -, -CY 2 =CY 3 represents -, -C≡C-, -CH=CH-CO-O-, -O-CO-CH=CH- or a single bond; R0 and R 00 each independently represent H or alkyl having 1 to 20 C atoms, Y 2 and Y 3 each independently represents H, F, Cl or CN.

[0492] X″ is preferably —O—, —S—, —CO—, —COO—, —OCO—, —O—COO—, —CO—NR 0 -, -NR 0 -CO-, -NR 0 -CO-NR 00 - or a single bond.

[0493] Exemplary spacer groups Sp and -Sp"-X"- include, for example, -(CH2) p1 -, -(CH2CH2O) q1 -CH2CH2-, -CH2CH2-S-CH2CH2-, -CH2CH2-NH-CH2CH2- or -(SiR 0 R 00 -O) p1 In the formula, p1 is an integer from 1 to 12, q1 is an integer from 1 to 3, and R 0 and R 00 has the meaning given above.

[0494] Particularly preferred spacer groups Sp and -Sp"-X"- are -(CH2) p1 -, -(CH2) p1 -O-, -(CH2) p1 -O-CO-, -(CH2) p1 -CO-O-, -(CH2) p1 -O-CO-O-, in which p1 and q1 have the meanings given above.

[0495] Particularly preferred radicals Sp″ are, in each case linear, ethylene, propylene, butylene, pentylene, hexylene, heptylene, octylene, nonylene, decylene, undecylene, dodecylene, octadecylene, ethyleneoxyethylene, methyleneoxybutylene, ethylenethioethylene, ethylene-N-methyliminoethylene, 1-methylalkylene, ethenylene, propenylene and butenylene.

[0496] The following examples illustrate the invention without limiting it. However, they show the skilled artisan the preferred mixing ideas, together with the compounds preferably used, their respective concentrations and their combinations with each other. In addition, the examples illustrate what properties and property combinations are available.

[0497] Preferred mixture components are shown in Table A below.

[0498] In Table A, 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; (O)C m H 2m+1 is C m H 2m+1 or O.C. m H 2m+1 means.

[0499] [Table 1]

[0500] [Table 2]

[0501] [Table 3]

[0502] [Table 4]

[0503]

Table 5

[0504]

Table 6

[0505]

Table 7

[0506]

Table 8

[0507]

Table 9

[0508]

Table 10

[0509]

Table 11

[0510]

Table 12

[0511]

Table 13

[0512]

Table 14

[0513] [Table 15]

[0514] [Table 16]

[0515] [Table 17]

[0516] [Table 18]

[0517] [Table 19]

[0518] [Table 20]

[0519] In a preferred embodiment of the invention, the LC medium according to the invention comprises one or more compounds selected from the group consisting of the compounds from Table A.

[0520] Table B shows possible chiral dopants which can be added to the LC media according to the invention.

[0521] [Table 21]

[0522] [Table 22]

[0523] The LC medium preferably comprises 0 to 10% by weight, in particular 0.01 to 5% by weight, particularly preferably 0.1 to 3% by weight, of a dopant. The LC medium preferably comprises one or more dopants selected from the group consisting of the compounds from table B.

[0524] Table C shows possible stabilizers which can be added to the LC media according to the invention, where n represents an integer from 1 to 12, preferably 1, 2, 3, 4, 5, 6, 7 or 8, and no terminal methyl group is shown.

[0525] [Table 23]

[0526] [Table 24]

[0527] [Table 25]

[0528] [Table 26]

[0529] [Table 27]

[0530] [Table 28]

[0531] [Table 29]

[0532] [Table 30]

[0533] The LC medium preferably comprises 0-10% by weight, in particular 1 ppm-5% by weight, particularly preferably 1 ppm-1% by weight, of a stabilizer. The LC medium preferably comprises one or more stabilizers selected from the group consisting of the compounds from table C.

[0534] Table D shows exemplary reactive mesogenic compounds which can be used in the LC medium according to the present invention.

[0535] [Table 31]

[0536] [Table 32]

[0537] [Table 33]

[0538] [Table 34]

[0539] [Table 35]

[0540] [Table 36]

[0541] [Table 37]

[0542] [Table 38]

[0543]

Table 39

[0544]

Table 40

[0545]

Table 41

[0546]

Table 42

[0547]

Table 43

[0548]

Table 44

[0549]

Table 45

[0550]

Table 46

[0551]

Table 47

[0552]

Table 48

[0553] [Table 49]

[0554] [Table 50]

[0555] [Table 51]

[0556] In a preferred embodiment, the mixture according to the invention comprises one or more polymerizable compounds, preferably selected from the polymerizable compounds of the formulae RM-1 to RM-178. Of these, 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, RM-122, R-139, RM-142, RM-143, RM-148 to RM-158, RM-164, RM-165 and RM-166 to RM-178 are particularly preferred.

[0557] Table E shows self-alignment additives for homeotropic alignment which can be used in the LC medium for SA-VA and SA-FFS displays according to the invention together with the polymerizable compounds of formula M.

[0558] [Table 52]

[0559] [Table 53]

[0560] [Table 54]

[0561]

Table 55

[0562]

Table 56

[0563]

Table 57

[0564]

Table 58

[0565]

Table 59

[0566]

Table 60

[0567]

Table 61

[0568]

Table 62

[0569]

Table 63

[0570]

Table 64

[0571] In a preferred embodiment the LC media, SA-VA and SA-FFS displays according to the invention comprise one or more SA additives selected from 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, in combination with one or more RM of formula M. EXAMPLES

[0572] The following examples illustrate the invention without limiting it. However, they show the skilled artisan the preferred mixing ideas, together with the compounds preferably used, their respective concentrations and their combinations with each other. In addition, the examples illustrate what properties and property combinations are available.

[0573] In addition, the following abbreviations and symbols are used: V0 is the capacitance threshold voltage [V] at 20°C, n e is the extraordinary refractive index at 20°C and 589 nm, n0 is the ordinary refractive index at 20° C. and 589 nm, Δn is the optical anisotropy at 20 °C and 589 nm, ε ⊥ is the dielectric constant perpendicular to the director at 20 °C and 1 kHz, ε ∥ is the dielectric constant parallel to the director at 20 °C and 1 kHz, Δε is the dielectric anisotropy at 20 °C and 1 kHz, cl.p., T(N,I) is the clearing point [℃], γ1 is the rotational viscosity at 20°C [mPa s], K1 is the elastic constant for "splay" deformation at 20°C [pN], K2 is the elastic constant for "twist" deformation at 20°C [pN], K3 is the elastic constant for "bend" deformation [pN] at 20°C.

[0574] Unless otherwise stated, all concentrations in this application are given in weight percent and refer to the corresponding total mixture, including any solid or liquid crystal components, and excluding solvent.

[0575] Unless otherwise stated, all temperature values ​​given in this application, such as the melting point T(C,N), the transition from smectic (S) to nematic (N) phase T(S,N) and the clearing point T(N,I), are given in degrees Celsius (°C). mp denotes the melting point and cl.p. the clearing point. Furthermore, C is the crystalline state, N is the nematic phase, S is the smectic phase and I is the isotropic phase. The data between these symbols represent the transition temperatures.

[0576] All physical properties are determined or have been determined in accordance with "Merck Liquid Crystals, Physical Properties of Liquid Crystals", November 1997, Merck, Germany, and unless otherwise stated in each case, a temperature of 20° C. applies, Δn is determined at 589 nm and Δε is determined at 1 kHz.

[0577] For the present invention, the term "threshold voltage" refers to the capacitive threshold (V0), also known as the Freedericks threshold, unless otherwise specified. Also, in the examples, and as is generally customary, the threshold voltage is generally referred to as the 10% relative contrast (V 10 ) may also be indicated.

[0578] Unless otherwise stated, the process of polymerizing the polymerizable compounds in the PSA display, as described above and below, is carried out at a temperature at which the LC medium exhibits a liquid crystal phase, preferably a nematic phase, and most preferably at room temperature.

[0579] Unless otherwise stated, the methods for preparing the test cells and measuring their electro-optical and other properties are as described hereinafter or similarly thereto.

[0580] The polymerizable compound is typically polymerized in the display or test cell by exposure to UV light of a defined intensity for a defined time while simultaneously applying a voltage to the display (typically 10V-30V AC, 1kHz).

[0581] The intensity is measured using a standard meter (Hoenle UV meter high end with UV sensor).

[0582] Tilt angles are typically determined using a Mueller matrix polarimeter "AxoScan" manufactured by Axometrics, Inc. Herein, lower values ​​(i.e., larger deviations from a 90° angle) correspond to larger tilts.

[0583] Unless otherwise stated, the term "tilt angle" refers to the angle between the LC director and the substrate, and "LC director" refers to the preferred orientation direction of the principal optical axes of the LC molecules in a layer of uniformly aligned LC molecules; in the case of calamitic, i.e., uniaxial, positively birefringent LC molecules, the "LC director" corresponds to the long molecular axis of the LC molecules.

[0584] <Example 1> The nematic LC host mixture N1 is formulated as follows:

[0585] [Table 65]

[0586] The polymerizable LC mixture C1 is prepared by adding 0.3% of the monomer RM-35 to the LC host mixture N1.

[0587] Chiral polymerizable LC mixture M1 is prepared by adding 0.91% of chiral dopant S-4011 and 0.3% of monomer RM-35 to LC host mixture N1.

[0588] [ka]

[0589] <Comparative Example 1> A C-PSVA display with a conventional design (ie, without a third electrode) as shown in FIG. 6a is assembled as follows.

[0590] The display consists of two parallel flat glass substrates separated by a spacer at a distance of 3.3 μm (cell gap). The top substrate is equipped with a first ITO electrode (50 nm thick) that is a continuous (i.e. unpatterned) electrode and a polyimide alignment layer (100 nm thick). The bottom substrate is equipped with a second ITO electrode (50 nm thick) with a fishbone pattern as shown in Figure 1(a) and an unrubbed polyimide alignment layer (100 nm thick).

[0591] The polymerizable LC mixture C1 is filled into the display by vacuum injection and the display is sealed. The LC layer has a retardation of 340 nm at a wavelength λ of 589 nm.

[0592] The patterned bottom electrode provides specific electric fields to orient the LC molecules in different azimuthal directions upon application of a voltage, also known as multi-domain alignment.

[0593] The PSA process is then carried out as illustrated in Figure 6(a-d): the display is exposed to UV light while a voltage is applied to the electrodes, causing photopolymerization of the monomer, thereby fixing the alignment direction of the LC molecules at the surface and generating a tilt angle.

[0594] When the display is driven (ie, a voltage is applied to selected pixels) after UV exposure, the tilt angle and multi-domain alignment will force the LC molecules into fixed directions as they are reoriented into a planar alignment.

[0595] The UV photopolymerization is carried out in two steps, the first step (UV1) to generate the tilt angle and the second step (UV2) to polymerize all the residual monomers that were not polymerized in the first step. In the UV1 step, a voltage (30 V ppSquare wave, 60Hz). No voltage is applied in UV2 step. Other conditions are as follows: UV1 (C-type lamp): 4.5mW / cm 2 30 to 200 seconds at room temperature UV2 (B-type lamp): 2.5mW / cm 2 120 minutes at room temperature.

[0596] After the above UV1 step, a tilt angle could be generated in the test cell and confirmed by measurement using an Otsuka TRETS-10 system.

[0597] <Comparative Example 2> A C-PSVA display with a conventional design (ie, without a third electrode) is constructed as described in Comparative Example 1.

[0598] The chiral polymerizable LC medium M1 is filled into the display by vacuum infusion and the display is sealed. The LC layer has a retardation of 450 nm at a wavelength λ of 589 nm and a helical pitch of about 13 μm.

[0599] The display then undergoes a PSA process that includes exposure to UV light in a two step process to generate a tilt angle and polymerize residual monomers under conditions as described in Comparative Example 1.

[0600] After the UV1 step, a tilt angle could be generated in the test cell and confirmed by measurement using an Otsuka TRETS-10 system.

[0601] <Example 1> A C-PSVA display according to the present invention with an additional third electrode is constructed as follows.

[0602] The display consists of two parallel flat glass substrates separated by a spacer at a distance of 3.5 μm (cell gap). The top substrate is equipped with a continuous (i.e. unpatterned) first ITO electrode (50 nm thick) and an unrubbed polyimide alignment layer (100 nm thick). The bottom substrate is equipped with an additional continuous third ITO electrode (50 nm thick), followed by an insulating layer of SiNx (300 nm thick), a second ITO electrode (50 nm thick) with a fishbone pattern as shown in Figure 1(a) and an unrubbed polyimide alignment layer (100 nm thick).

[0603] The chiral polymerizable LC medium M1 is filled into the display by vacuum infusion and the display is sealed. The LC layer has a retardation of 450 nm at a wavelength λ of 589 nm and a helical pitch of about 13 μm.

[0604] The PSA process is then carried out as illustrated in Fig. 7(a-e). First (Fig. 7b), an additional third electrode is grounded and a 30 V pp A square wave, 60 Hz voltage is applied to the first (upper) and second (lower) electrodes for 40 seconds.

[0605] The potential of the third electrode is then switched from ground potential to the same potential as the second electrode (Figure 7c).

[0606] The result is improved and more uniform alignment of the LC molecules.

[0607] Then, UV photopolymerization is carried out in two steps UV1 and UV2 to generate the tilt angle and polymerize the residual monomer as described in Comparative Example 1 (FIG. 7d), except that in step UV1, voltage is applied to the first, second and third electrodes as described above, and in step UV2, no voltage is applied. The other conditions are as follows: UV1 (C-type lamp): 4.5mW / cm 2 30 to 200 seconds at room temperature UV2 (B-type lamp): 2.5mW / cm2 120 minutes at room temperature.

[0608] After the UV1 step, a tilt angle could be generated in the test cell and confirmed by measurement using an Otsuka TRETS-10 system.

[0609] During operation of the display, the second and third electrodes will be set to the same potential to drive the display.

[0610] By using the third electrode and PSA process as described above, the uniform linear electric field generated at the third electrode increases the transmittance of the display in both the trunk dark line and edge dark line regions as well as throughout the pixel area.

[0611] These advantageous effects are also illustrated in FIGS.

[0612] 2(a) shows a microscope image of a display according to Comparative Example 1 with a conventional electrode design and no chiral dopant in the LC medium. When the display is driven, the appearance of dark trunk lines and dark edge lines between the individual pixels can be clearly observed.

[0613] Figure 2(b) shows a microscope image of a display according to Comparative Example 2 with a chiral dopant in the LC medium with a conventional electrode design. When the display is driven, it can be seen that the appearance of the dark trunk lines is suppressed, however, the dark edge lines are still visible.

[0614] 2(c) shows a microscope image of a display according to the display example 1 of the present invention with an additional third electrode and with a chiral dopant in the LC medium. It can be seen that when the display is driven, the appearance of both the dark trunk lines and the dark edge lines is suppressed and the transmittance is higher.

[0615] FIG. 8 shows the relative transmittance (%) versus lateral pixel dimension for a display according to Comparative Example 1 (graph a) and for a display according to Example 1 (graph b).

[0616] It can be seen that the display according to Example 1 has a significantly higher transmittance. The full area transmittance after integrating the graph for the display according to Example 1 is about 10% higher compared to the display according to Comparative Example 1.

Claims

1. A chiral polymer-stabilized alignment (C-PSA) mode LC display, comprising: a) a first substrate comprising a first electrode and optionally a first alignment layer, said first electrode optionally having a pattern and optionally divided into a plurality of pixels; b) a layer comprising a nematic LC medium having negative dielectric anisotropy, comprising a chiral additive and further comprising a polymer formed from one or more polymerizable compounds; c) a second substrate comprising a second electrode and optionally a second alignment layer, said second electrode having a pattern and divided into a plurality of pixels; d) optionally including a color filter disposed adjacent the second electrode; with the proviso that the optional first and second alignment layers, if present, are arranged so that they are in contact with the LC medium; The second substrate further comprises a third electrode and an electrical insulating layer between the second and third electrodes, and the third electrode may have a pattern and may be divided into a plurality of pixels; with the proviso that the display further comprises a non-linear element for electronically addressing individual pixels, said non-linear element contacting the second electrode and / or the third electrode or contacting the first electrode; and wherein said one or more polymerizable compounds in the LC medium are polymerized in situ after the LC medium has been dispensed between two substrates while applying a voltage to at least the first and second electrodes.

2. 2. The display of claim 1, wherein the second electrode has a fishbone pattern.

3. 2. The display of claim 1, wherein the first and third electrodes are unpatterned.

4. 2. A display as claimed in claim 1, wherein the third electrode is patterned and the first electrode is unpatterned.

5. 2. A display according to claim 1, characterised in that the first substrate is the top substrate and the non-linear means for electronically addressing individual pixels are in contact with the second and optionally third electrodes.

6. 2. A display according to claim 1, wherein the second substrate is the top substrate and the non-linear means for electronically addressing the individual pixels is in contact with the first electrode.

7. LC display according to claim 1, characterized in that the LC medium additionally comprises one or more additives selected from the group consisting of stabilizers, polymerization initiators and self-aligning additives.

8. 10. The display of claim 1, wherein the polymer is formed by UV photopolymerization of the one or more polymerizable compounds.

9. 2. A display according to claim 1, characterized in that it is a C-PSVA mode display.

10. 10. The display of claim 1, further comprising first and second compensation films selected from biaxial compensation films, sandwiching the display.

11. 10. A method for manufacturing the display of claim 1, comprising the steps of: a) providing a first substrate and a second substrate, the first substrate being provided with a first electrode and optionally a first alignment layer, and the second substrate being provided with a second electrode, optionally a second alignment layer, a third electrode, an electrical insulating layer between the second and third electrodes, and optionally a color filter; However, the first and / or second substrate is provided with a fixing means for fixing the first and second substrates at a fixed distance from each other and with their planes parallel to each other; with the proviso that the second electrode has a pattern and is divided into a plurality of pixels, and the first and / or third electrode optionally has a pattern and optionally is divided into a plurality of pixels; with the proviso that the display further comprises a non-linear element for electronically addressing individual pixels, said non-linear element either in contact with the second electrode and / or the third electrode or in contact with the first electrode; b) distributing a nematic LC medium between first and second substrates such that the LC medium is in contact with the first and second alignment layers, if present, However, the LC medium has a negative dielectric anisotropy, A) a liquid crystal component A comprising mesogenic or liquid crystal molecules (hereinafter also referred to as "LC host mixture"); B) a polymerizable component B containing one or more polymerizable compounds; C) one or more chiral additives; D) optionally containing one or more further additives; c) applying a voltage to the first and second electrodes; d) polymerizing the polymerizable compounds of the polymerizable component B of the LC medium between the first and second substrates by exposure to UV radiation while applying a voltage; e) optionally subjecting the LC medium to a second polymerization step by exposure to UV radiation without applying a voltage to the first, second or third electrode, thereby polymerizing all polymerizable compounds that have not reacted in step d).

12. 10. Use of the LC display according to claim 1 as an energy-saving display.

Images