Liquid crystal medium

Abstract

To provide a liquid crystalline medium.SOLUTION: The present invention relates to LC media and to LC displays containing these media, especially to displays addressed by an active matrix, and in particular to displays of the IPS, PS-IPS, FFS, PS-FFS, HB-FFS, U-IPS, TN, PS-TN, STN or TN-TFT mode.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to LC (liquid crystal) media and LC displays (LCDs) containing these media, in particular to LCDs addressed in active matrix, and in particular to LCDs in IPS, PS-IPS, FFS, PS-FFS, HB-FFS, U-IPS, TN, PS-TN, STN or TN-TFT modes.

Background Art

[0002] LCDs are used in many fields for displaying information. LCDs are used in both direct-view displays and projection displays. The electro-optical modes used are, for example, the twisted nematic (TN), super twisted nematic (STN), optically compensated bend (OCB), and electrically controlled birefringence (ECB) modes, along with their various modifications, and others. All of these modes utilize an electric field substantially perpendicular to the substrate or the LC layer. In addition to these modes, there are also electro-optical modes that utilize an electric field substantially parallel to the substrate or the LC layer, for example, the in-plane switching (IPS) mode (as disclosed in, for example, German Patent No. 40 00 451 (Patent Document 1) and European Patent No. 0 588 568 (Patent Document 2)) and the fringe-field switching (FFS) mode, etc. In this mode, a strong "fringe field" exists, i.e., a strong electric field exists in the vicinity of the electrode periphery, and an electric field having both a strong vertical component and a strong horizontal component exists across the cell. These latter two electro-optical modes are used particularly in LCDs for modern desktop monitors and displays for television sets and multimedia applications. The liquid crystal according to the present invention is preferably used in this type of display. A dielectrically positive liquid crystal medium having a fairly low value of dielectric anisotropy is generally used in FFS displays, but in some cases, a liquid crystal medium having a dielectric anisotropy of only about 3 or less is also used in IPS displays.

[0003] Further developments are so-called PS (polymer sustained) or PSA (polymer sustained alignment) displays, sometimes also using the term "polymer stabilised". In these, one or more polymerisable compounds (one or more), preferably polymerisable monomer compounds (one or more), in a small amount (e.g. 0.3 wt%, typically less than 1 wt%) are added to the LC medium and after filling the display with the LC medium, while optionally applying a voltage to the electrodes of the display, polymerisation or crosslinking is carried out in situ, usually by UV photopolymerisation. The polymerisation is carried out at a temperature at which the LC medium exhibits the LC phase, usually at room temperature. It has proven particularly appropriate to add a polymerisable mesogen or LC compound, also known as a reactive mesogen or "RM" (reactive mesogen), to the LC mixture.

[0004] These displays require new liquid crystal media with improved properties. In particular, for many types of applications, it is necessary to improve the addressing time. Thus, a liquid crystal medium with a lower viscosity (η), in particular a lower rotational viscosity (γ1), is required. In addition to these viscosity parameters, the medium must have a nematic phase within an appropriate position and range of widths, and the appropriate birefringence (Δn) and dielectric anisotropy (Δε) must be high enough for a moderately low operating voltage.

[0005] The displays according to the invention are preferably addressed by an active matrix (active matrix LCD, abbreviated AMD), preferably by a matrix of thin film transistors (TFT: thin film transistor). However, the liquid crystals according to the invention can also be advantageously used in displays with other known addressing means.

[0006] LC media suitable for LCDs, and especially for IPS displays, are known, for example, from Japanese Patent Application Laid-Open No. 07-181439 (Patent Document 3), European Patent No. 0 667 555 (Patent Document 4), European Patent No. 0 673 986 (Patent Document 5), German Patent No. 195 09 410 (Patent Document 6), German Patent No. 195 28 106 (Patent Document 7), German Patent No. 195 28 107 (Patent Document 8), International Publication No. 96 / 23851 (Patent Document 9) and International Publication No. 96 / 28521 (Patent Document 10). However, these LC media have certain drawbacks. Most of them, among other drawbacks, result in an unfavorably long addressing time, have inappropriate resistance values and / or require an excessively high operating voltage. In addition, there is a need to improve the low-temperature behavior of LCDs. In this case, improvements are required in both operating characteristics and storage life.

[0007] Especially in the case of LC media for use in the expanding markets of public information displays (PIDs) and in-vehicle displays, high reliability and a wide operating range are very important factors. Therefore, for these applications, LC media having a high clearing temperature (Tni), good LTS (Low Temperature Stability) and high reliability are desired.

Prior Art Documents

Patent Documents

[0008]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Patent Document 6

Patent Document 7

Patent Document 8

Patent Document 9

Patent Document 10

Summary of the Invention

Problems to be Solved by the Invention

[0009] In particular, the present invention aims to provide a medium for active matrix displays, especially for this type of FFS, IPS, TN or STN display, especially those of the TFT (thin film transistor) type, which do not exhibit the drawbacks shown above or exhibit them to a lesser extent, preferably showing one or more of a wide operating range, a high clearing temperature, high reliability, a low threshold voltage, a high dielectric anisotropy, good low temperature stability (LTS), a low rotational viscosity, and a fast response time.

[0010] This object has been achieved by providing an LC medium as described and claimed below.

Means for Solving the Problems

[0011] The present invention relates to an LC medium having a positive dielectric anisotropy, characterized by containing one or more compounds of formula I in a concentration of more than 0% and 10% or less.

[0012]

Chemical Formula

[0013] Preferably, the LC medium has a birefringence of less than 0.15, more preferably from 0.8 to 9.15.

[0014] The present invention further relates to the use of an LC medium as described above and below for electro-optical purposes, in particular in shutter glasses, 3D applications, IPS, PS-IPS, FFS, PS-FFS, HB-FFS, U-IPS, TN, PS-TN, STN or TN-TFT displays.

[0015] The present invention further relates to an electro-optical LC display comprising an LC medium as described above and below, in particular an IPS, PS-IPS, FFS, PS-FFS, HB-FFS, U-IPS, TN, PS-TN, STN or TN-TFT display.

[0016] The present invention further relates to a method for preparing an LC medium as described above and below, the method comprising the step of mixing one or more compounds of formula I with one or more further LC compounds and, as optional components, one or more additives.

Embodiments for Carrying Out the Invention

[0017] Also in the present application, all atoms include their isotopes. In particular, one or more hydrogen atoms (H) may be replaced by deuterium (D), which is particularly preferred depending on the embodiment. In particular, in the case of low concentrations, highly deuterating the compound enables or simplifies the analytical determination of the compound.

[0018] R 0When it represents an alkyl group and / or an alkoxy group, this may be linear or branched. Preferably it is linear, has 2, 3, 4, 5, 6 or 7 C atoms and correspondingly preferably represents ethyl, propyl, butyl, pentyl, hexyl, heptyl, ethoxy, propoxy, butoxy, pentoxy, hexyloxy or heptyloxy, furthermore methyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, methoxy, octyloxy, nonyloxy, decyloxy, undecyloxy, dodecyloxy, tridecyloxy or tetradecyloxy. R 0 preferably represents a linear alkyl having 2 to 6 C atoms.

[0019] The oxaalkyl preferably represents linear 2-oxapropyl (=methoxymethyl), 2-(=ethoxymethyl) or 3-oxabutyl (=2-methoxyethyl), 2-, 3- or 4-oxapentyl, 2-, 3-, 4- or 5-oxahexyl, 2-, 3-, 4-, 5- or 6-oxaheptyl, 2-, 3-, 4-, 5-, 6- or 7-oxaoctyl, 2-, 3-, 4-, 5-, 6-, 7- or 8-oxanonyl, 2-, 3-, 4-, 5-, 6-, 7-, 8- or 9-oxadecyl.

[0020] R 0 When R represents an alkyl group in which one CH 2 group is replaced by a -CH=CH- group, this may be linear or branched. Preferably it is linear and has 2 to 10 C atoms. Thus, it particularly represents vinyl, prop-1- or 2-enyl, but-1-, -2- or -3-enyl, pent-1-, -2-, -3- or -4-enyl, hex-1-, -2-, -3-, -4- or -5-enyl, pent-1-, -2-, -3-, -4-, -5- or -6-enyl, oct-1-, -2-, -3-, -4-, -5-, -6- or -7-enyl, non-1-, -2-, -3-, -4-, -5-, -6-, -7- or -8-enyl, dec-1-, -2-, -3-, -4-, -5-, -6-, -7-, -8- or -9-enyl.

[0021] R 0 When representing an alkyl or alkenyl group in which at least monosubstituted by a halogen, this group is preferably linear, and the halogen is preferably F or Cl. In the case of polysubstitution, the halogen is preferably F. Also, the resulting group includes perfluoro groups. In the case of monosubstitution, the fluorine or chlorine substituent may be at any desired position, but is preferably at the ω-position.

[0022] In the above and below formulas, X 0 is preferably F, Cl, or a mono- or polyfluorinated alkyl or alkoxy group having 1, 2 or 3 C atoms, or a mono- or polyfluorinated alkenyl group having 2 or 3 C atoms. X 0 is particularly preferably F, Cl, CF 3 , CHF 2 , OCF 3 , OCHF 2 , OCFHCF 3 , OCFHCHF 2 , OCFHCHF 2 , OCF 2 CH 3 , OCF 2 CHF 2 , OCF 2 CHF 2 , OCF 2 CF 2 CHF 2 , OCF 2 CF 2 CHF 2 , OCFHCF 2 CF 3 , OCFHCF 2 CHF 2 , OCF 2 CF 2 CF 3 , OCF 2 CF 2 CClF 2 , OCClFCF 2 CF 3 , OCH=CF 2 or CH=CF 2 , very particularly preferably F or OCF 3, further CF 3 , OCF = CF 2 , OCHF 2 or OCH = CF 2 .

[0023] X 0 is F or OCF 3 , particularly preferably a compound in which F is preferably represented.

[0024] In the compound of formula I, R 1 and R 2 are preferably selected from ethyl, propyl, butyl and pentyl, all of which are linear.

[0025] Preferred compounds of formula I are selected from the following sub-formulas.

[0026] [Chemical formula]

[0027] Compounds of formula I2 are highly preferred.

[0028] The concentration of the compounds of formula I and its sub-formulas in the LC medium is preferably 0.2 - 10%, more preferably 1.0 - 10%, and very preferably 1.0 - 8%.

[0029] Preferably, the LC medium contains one, two or three compounds of formula I or its sub-formulas.

[0030] Further preferred embodiments of the LC medium according to the present invention are shown below and include any combination thereof.

[0031] · The medium additionally contains one or more compounds selected from the following formulas.

[0032] [Chemical formula] In the formula, each group has the following meanings, which are the same or different in each occurrence, independently of one another.

[0033]

Chem.

Chem.

Chem.

[0034] In the compounds of formula II and III and their sub-formulas, R 0 preferably represents linear alkyl having 1 to 6 C atoms, especially methyl, ethyl or propyl, further alkenyl having 2 to 6 C atoms, especially vinyl, 1E-propenyl, 1E-butenyl, 3-butenyl, 1E-pentenyl, 3E-pentenyl or 4-pentenyl.

[0035] · The LC medium is Y 0is H and preferably contains one or more compounds of Formula II selected from the group consisting of the following sub-formulas.

[0036]

Chemical formula

[0037]

Chemical formula

[0038] Preferred compounds are those of Formula II1, II2 and II3, and very preferably those of Formula II1 and II2.

[0039] In the compounds of Formula II1 to II7, R 0 preferably represents alkyl having 1 to 6 carbon atoms, very preferably ethyl or propyl, and X 0 preferably represents F or OCF 3 , and very preferably represents F.

[0040] · The medium is Y 0 is CH 3 and preferably contains one or more compounds of Formula II selected from the group consisting of the following sub-formulas.

[0041]

Chemical formula

[0042]

Chemical formula

[0043] Preferred compounds are those of Formula IIA1, IIA2 and IIA3, and very preferably those of Formula IIA1 and IIA2.

[0044] In the compounds of formulae IIA1 to IIA7, R 0 preferably represents alkyl having 1 to 6 C atoms, very preferably ethyl or propyl, and X 0 preferably represents F or OCF 3 , very preferably represents F.

[0045] · The medium is Y 0 is H and preferably contains one or more compounds of formula III selected from the group consisting of the following sub-formulae.

[0046]

Chemical formula

[0047]

Chemical formula

[0048]

Chemical formula

[0049]

Chemical formula

[0050]

Chemical formula

[0051] Preferred compounds are those of formulae III1, III4, III6, III16, III19 and III20.

[0052] In the compounds of formulae III1 to III21, R 0 preferably represents alkyl having 1 to 6 C atoms, very preferably ethyl or propyl, and X0 is preferably F or OCF 3 and very preferably represents F, and Y 2 preferably represents F.

[0053] · The medium is Y 0 is CH 3 and preferably contains one or more compounds of formula III selected from the group consisting of the following sub-formulas.

[0054]

Chemical formula

[0055]

Chemical formula

[0056]

Chemical formula

[0057]

Chemical formula

[0058]

Chemical formula

[0059] Preferred compounds are those of formula IIIA1, IIIA4, IIIA6, IIIA16, IIIA19 and IIIA20.

[0060] In the compounds of formulae IIIA1 to IIIA21, R 0 preferably represents alkyl having 1 to 6 C atoms, very preferably ethyl or propyl, and X 0 is preferably F or OCF 3 and very preferably represents F, and Y 2Preferably represents F.

[0061] · The medium contains one or more compounds selected from the following formula.

[0062]

Chemical formula

[0063] · The medium contains one or more compounds of formula IV selected from the following sub-formulas.

[0064]

Chemical formula

[0065] R 0 preferably represents an alkyl having 1 to 6 C atoms. X 0 preferably represents F or OCF 3 , further preferably OCF=CF 2 or Cl.

[0066] · The medium contains one or more compounds of formula IVa selected from the following sub-formulas.

[0067]

Chemical formula

[0068] · The medium contains one or more compounds of formula IVc selected from the following sub-formulas.

[0069]

Chemical formula

[0070] · The medium contains one or more compounds of formula V selected from the following sub-formulas.

[0071]

Chemical formula

[0072]

Chemical formula

[0073] R 0 preferably represents an alkyl having 1 to 6 carbon atoms. X 0 preferably represents F or OCF 3 , more preferably OCHF 2 , CF 3 , OCF=CF 2 and OCH=CF 2 represents.

[0074] · The medium contains one or more compounds of Formula VI selected from the following sub-formulas.

[0075]

Chemical formula

[0076] R 0 preferably represents an alkyl having 1 to 6 carbon atoms. X 0 is preferably F, more preferably OCF 3 , CF 3 , CF=CF 2 , OCHF 2 and OCH=CF 2 represent.

[0077] · The medium contains one or more compounds of Formula VII selected from the following sub-formulas.

[0078]

Chemical formula

[0079] R 0 preferably represents an alkyl having 1 to 6 carbon atoms. X 0 is preferably F, more preferably OCF 3 , OCHF 2 and OCH=CF 2 represent.

[0080] · The medium additionally contains one or more compounds selected from the following formula.

[0081]

Chemical formula

[0082] · The medium contains one or more compounds of formulae IX to XII selected from the following sub-formulae.

[0083] [Chemical formula] In the formula, "alkyl" has the meaning given in formula IX.

[0084] In formulae IX, IXa and IXb, "alkyl" preferably represents C 2 H 5 , n-C 3 H 7 , n-C 4 H 9 or n-C 5 H 11 and particularly preferably n-C 3 H 7 and represents.

[0085] In formulae IXa and IXb, "alkyl" preferably represents CH 3 or C 2 H 5 and particularly preferably CH 3 and represents.

[0086] · The medium contains one or more compounds of formulae IX to XII selected from the following sub-formulae.

[0087] [Chemical formula] Very preferred are the compounds of formulae IXa2, IXb1, XIa1 and XIa2.

[0088] · The medium does not contain any compound of the following formula.

[0089] [Chemical formula] In the formula, L 1 and L 2 each independently represent H or F, R' represents alkyl or alkoxy having 1 to 12 C atoms, identical or different in each occurrence, R” represents alkenyl having 2 to 7 C atoms and containing a terminal vinyl group, identical or different in each occurrence, R''' represents R' or R”.

[0090] · The medium additionally contains one or more compounds selected from the following formula.

[0091] [Chemical formula] In the formula, R 3 and R 4 each independently represent n-alkyl, alkoxy, oxaalkyl, fluoroalkyl or alkenyl having up to 6 C atoms each, preferably alkyl having 1 to 6 C atoms each or alkenyl having 2 to 6 C atoms each, independently of one another.

[0092] · The medium contains one or more compounds of formula XV selected from the following sub-formulae.

[0093] [Chemical formula] In the formula, "alkyl" has the meaning shown above and preferably represents methyl, ethyl or propyl.

[0094] · The medium contains one or more compounds of formula XV selected from the following sub-formulas.

[0095]

Chemical formula

[0096] · The medium contains one or more compounds of formula XVI.

[0097]

Chemical formula

[0098] Particularly preferred compounds of formula XVI are those of the following sub-formulas.

[0099]

Chemical formula

[0100] Particularly preferred are the compounds of formula XVIb, XVIc and XVIg. The compounds of the following formula are very particularly preferred.

[0101]

Chemical formula

[0102]

Chemical formula

[0103] · The medium contains one or more compounds of the following formula.

[0104]

Chemical formula

[0105] · The medium additionally contains one or more compounds selected from the following formula.

[0106]

Chemical formula

[0107] A very preferred mixture according to the invention comprises one or more compounds of formula XXIa.

[0108]

Chemical formula

[0109] More preferably, the mixture according to the invention comprises one or more compounds of formula XXIIIa.

[0110]

Chemical formula

[0111] ·The medium additionally contains one or more compounds of formula XXIV.

[0112]

Chemical formula

Chemical Formula

[0113] In Formula XXIV, X 0 may also represent an alkyl group having 1 to 6 C atoms or an alkoxy group having 1 to 6 C atoms. The alkyl or alkoxy group is preferably linear.

[0114] R 0 preferably represents an alkyl having 1 to 6 C atoms. X 0 preferably represents F.

[0115] · The compound of Formula XXIV is preferably selected from the following formulas.

[0116]

Chemical Formula

[0117]

Chemical Formula

[0118]

Chemical Formula

[0119] · R 0 is a linear alkyl or alkenyl having 2 to 6 C atoms.

[0120] · The medium contains one or more compounds of the following formula.

[0121] [Chemical formula] In the formula, R 3 and X 0 have the meanings shown above. R 3 preferably represents an alkyl having 1 to 6 C atoms. X 0 preferably represents F or Cl. In formula XXIV, X 0 very preferably represents Cl.

[0122] · The medium contains one or more compounds of the following formula.

[0123] [Chemical formula] In the formula, R 3 and X 0 have the meanings shown above. R 3 preferably represents an alkyl having 1 to 6 C atoms. X 0 preferably represents F. The medium according to the present invention particularly preferably contains one or more compounds of formula XXIX in which X 0 preferably represents F. The compound(s) of formulae XXVI to XXIX (one or more) are used in the mixture according to the present invention in an amount of 1 to 20% by weight, particularly preferably 1 to 15% by weight. A particularly preferred mixture contains at least one compound of formula XXIX.

[0124] Very preferably, the mixture according to the present invention contains one or more compounds of formula XXIXa.

[0125] [Chemical formula] In the formula, R 3has the meaning shown above and preferably represents a linear alkyl, especially ethyl, n-propyl, n-butyl and n-pentyl, very preferably n-propyl. The compound(s) of formula XXIXa is / are preferably used in the mixture according to the invention in an amount of 1 to 15% by weight, particularly preferably 2 to 10% by weight.

[0126] · The medium contains one or more compounds of the following formula.

[0127]

Chemical formula

[0128] The preferred compound of formula XXX is of formula XXXa.

[0129]

Chemical formula

[0130] Further preferred LC media include any combination thereof and are selected from the following preferred embodiments.

[0131] · The medium preferably contains one or more compounds of formula II, preferably selected from formulae II1, II2 and II3, very preferably formulae II1 and II2. The individual concentration of each of these compounds is preferably 1 to 15% by weight. The total concentration of these compounds is preferably 5 to 25% by weight.

[0132] · The medium preferably contains one or more compounds of formula III, preferably selected from formula III1, III4, III6, III16, III19 and III20, very preferably from formula III16 and III20. The individual concentration of each of these compounds is preferably 1 to 15% by weight. The total concentration of these compounds is preferably 2 to 25% by weight.

[0133] · The medium preferably contains one or more compounds of formula IV, preferably selected from formula IVa or IVc, very preferably from formula IVa1 or IVc1. The individual concentration of each of these compounds is preferably 1 to 15% by weight. The total concentration of these compounds is preferably 5 to 25% by weight.

[0134] · The medium contains one or more compounds of formula IX, preferably selected from formula IXa and IXb, very preferably from formula IXa2 and Xb1. The individual concentration of each of these compounds is preferably 1 to 15% by weight. The total concentration of these compounds is preferably 5 to 25% by weight.

[0135] · The medium preferably contains one or more compounds of formula XI selected from formula XIa and XIb. The individual concentration of each of these compounds is preferably 1 to 20% by weight. The total concentration of these compounds is preferably 5 to 25% by weight.

[0136] · The medium contains one or more compounds of formula XII, preferably of formula XIIa. The total concentration of these compounds is preferably 3 to 20% by weight.

[0137] · The medium contains one or more compounds of formula XV, preferably selected from formula XVd and XVe, very preferably from formula XVd1 and XVe1. The individual concentration of each of these compounds is preferably 1 to 10% by weight. The total concentration of these compounds is preferably 2 to 15% by weight.

[0138] · The medium contains one or more compounds of formula XVIc, preferably formula XVIc2. The concentration of these compounds is preferably 1 to 15% by weight.

[0139] · The medium contains one or more compounds of formula XVIg, preferably formula XVIg1 and / or XVIg2. The concentration of these compounds is preferably 5 to 25% by weight.

[0140] · The medium contains one or more compounds of formula XVIIa or XVIIb. The concentration of these compounds is preferably 0.5 to 5% by weight.

[0141] · The medium contains one or more compounds of formula XXI, preferably formula XXIa. The concentration of these compounds is preferably 0.5 to 8% by weight.

[0142] · The medium contains one or more compounds of formula XXIII, preferably formula XXIIIa. The concentration of these compounds is preferably 0.5 to 5% by weight.

[0143] · The medium contains one or more compounds of formula XXIX, preferably formula XXIXa. The concentration of these compounds is preferably 2 to 10% by weight.

[0144] · The medium contains one or more compounds of formula XXX, preferably formula XXXa. The concentration of these compounds is preferably 2 to 10% by weight.

[0145] · The medium contains one or more compounds of formula I and one or more compounds selected from the group consisting of formulas II, III, IV, IX, XI, XII, XV, XVI, XXI, XXIX, and XXX.

[0146] · The medium contains a compound of formula I and one or more compounds selected from the group consisting of formulas II1, II2, II3, III1, III4, III6, III16, III19, III20, IVa, IVc, IXa, IXb, XIa, XIb, XIIa, XVd, XVe, XVIc, XXIa, XXIXa, and XXXa.

[0147] · The proportion in the whole mixture of the compounds of Formulas II, III, IV, IX, XI, XII, XV, XVI, XXI, XXIX and XXX is 90 to 99% by weight.

[0148] · The proportion in the whole mixture of the compounds of Formulas II1, II2, II3, III1, III4, III6, III16, III19, III20, IVa, IVc, IXa, IXb, XIa, XIb, XIIa, XVd, XVe, XVIc, XXIa, XXIXa and XXXa is 90 to 99% by weight.

[0149] In this application, the term "alkyl" or "alkyl" * (alkyl * ) includes linear and branched alkyl groups having 1 to 6 carbon atoms, particularly the linear groups methyl, ethyl, propyl, butyl, pentyl and hexyl. Groups having 2 to 5 carbon atoms are generally preferred.

[0150] The term "alkenyl" or "alkenyl" * (alkenyl * ) includes linear and branched alkenyl groups having 2 to 6 carbon atoms, particularly linear groups. Preferred alkenyl groups are C 2 ~C 7 -1E-alkenyl, C 4 ~C 6 -3E-alkenyl, particularly C 2 ~C 6 -1E-alkenyl. Examples of particularly preferred alkenyl groups are vinyl, 1E-propenyl, 1E-butenyl, 1E-pentenyl, 1E-hexenyl, 3-butenyl, 3E-pentenyl, 3E-hexenyl, 4-pentenyl, 4Z-hexenyl, 4E-hexenyl and 5-hexenyl. Groups having up to 5 carbon atoms, particularly CH 2 =CH, CH 3 CH=CH are generally preferred.

[0151] The term "fluoroalkyl" preferably encompasses linear groups having a terminal fluorine, i.e., fluoromethyl, 2-fluoroethyl, 3-fluoropropyl, 4-fluorobutyl, 5-fluoropentyl, 6-fluorohexyl and 7-fluoroheptyl. However, other positions of fluorine are not excluded.

[0152] The term "oxaalkyl" or "alkoxy" preferably encompasses linear groups of the formula C n H 2n+1 -O-(CH 2 ) m wherein n and m each independently represent 1 to 6. Also, m may represent 0. Preferably, n = 1 and m = 1 to 6 or m = 0 and n = 1 to 3.

[0153] R 0 and X 0 By appropriate selection of the meanings of, the addressing time, threshold voltage, steepness of the transmission characteristic line, etc. can be changed in a desired manner. For example, 1E-alkenyl groups, 3E-alkenyl groups, 2E-alkenyloxy groups, etc. generally result in a shorter addressing time, improved nematic tendency, elastic constant k 33 (bend) and a higher ratio between k 11 (splay) compared to alkyl and alkoxy groups. 4-alkenyl groups, 3-alkenyl groups, etc. generally give a lower threshold voltage and a lower value of k 33 / k 11 compared to alkyl and alkoxy groups. The mixtures according to the invention are distinguished in particular by a high value of Δε and thus have a significantly faster response time than mixtures from the prior art.

[0154] The optimal mixing ratio of the compounds of the above formula substantially depends on the desired properties, the selection of the components of the above formula and the selection of any further components that may be present.

[0155] The appropriate mixing ratio within the ranges indicated above can be readily determined on a case-by-case basis.

[0156] The total amount of the compounds of the above formula in the LC medium according to the invention is not critical. Thus, the mixture may contain one or more further components for the purpose of optimizing various properties. However, the observed effect on the desired improvement of the properties of the medium is generally greater the higher the total concentration of the compounds of the above formula.

[0157] In a particularly preferred embodiment, the LC medium according to the invention is such that X 0 is F, OCF 3 , OCHF 2 , OCH=CF 2 , OCF=CF 2 or OCF 2 -CF 2 H and contains compounds of formulas IV to VIII (preferably IV and V). The preferred synergistic action with the compounds of formulas IA, IIA, IB and IIB results in particularly advantageous properties. In particular, mixtures containing compounds of formulas IA or IIA and IB or IIB are distinguished by their low threshold voltages.

[0158] The individual compounds of the above formulas and their sub-formulas that can be used in the LC medium according to the invention are known or can be prepared analogously to known compounds.

[0159] In another preferred embodiment of the invention, the LC medium additionally contains one or more polymerizable compounds. The polymerizable compounds are preferably selected from formula M.

[0160]

Chemical formula

[0161] Particularly preferred compounds of formula I are those in which B 1 and B 2 are each independently of the other 1,4-phenylene, 1,3-phenylene, naphthalene-1,4-diyl, naphthalene-2,6-diyl, phenanthrene-2,7-diyl, 9,10-dihydro-phenanthrene-2,7-diyl, anthracene-2,7-diyl, fluorene-2,7-diyl, coumarin, flavone (however, one or more CH groups in these groups may optionally be replaced by N. ), cyclohexane-1,4-diyl (however, one or more non-adjacent CH 2 groups may optionally be replaced by O and / or S. ), 1,4-cyclohexenylene, bicyclo[1.1.1]pentane-1,3-diyl, 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, indane-2,5-diyl or octahydro-4,7-methanoindane-2,5-diyl, provided that all of these groups may be unsubstituted or mono- or polysubstituted by L as defined above.

[0162] Particularly preferred compounds of formula M are those in which B 1 and B 2 each independently of the other represent 1,4-phenylene, 1,3-phenylene, naphthalene-1,4-diyl, naphthalene-2,6-diyl.

[0163] Very preferred compounds of formula M are selected from the following formulas.

[0164]

Chem.

[0165]

Chem.

[0166]

Chem.

[0167]

Chem.

[0168]

Chem.

[0169]

Chem.

[0170] Compounds of formula M2 and M13 are particularly preferred.

[0171] Trifunctional compounds M15 to M31, especially M17, M18, M19, M22, M23, M24, M25, M30, M31 and M32 are more preferred.

[0172] In the compounds of formula M1 to M32, the group

[0173] [Chemical formula] In the formula, L has, in each occurrence, the same or different meaning, one of the meanings given above or below, and preferably F, Cl, CN, NO 2 , CH 3 , C 2 H 5 , C(CH 3 ) 3 , CH(CH 3 ) 2 , CH 2 CH(CH 3 )C 2 H 5 , OCH 3 , OC 2 H 5 , COCH 3 , COC 2 H 5 , COOCH 3 , COOC 2 H 5 , CF 3 , OCF 3 , OCHF 2 , OC 2 F 5 or P-Sp-, very preferably F, Cl, CN, CH 3 , C 2 H 5 , OCH 3 , COCH 3 , OCF 3 or P-Sp-, more preferably F, Cl, CH 3 , OCH 3 , COCH 3 or OCF 3 , particularly F or CH 3 is.

[0174] Preferred compounds of formulas M1 to M32 are those in which P 1 , P 2 and P 3 represent acrylate, methacrylate, oxetane, or epoxy groups, very preferably acrylate or methacrylate groups.

[0175] Even more preferred compounds of formulas M1 to M32 are those in which Sp1 and Sp 2 and Sp 3 is a compound in which the bond is a single bond.

[0176] More preferred compounds of Formulas M1 - M32 are those in which, in the formula, Sp 1 and Sp 2 and Sp 3 one of them is a single bond, and Sp 1 and Sp 2 and Sp 3 the other one of them is a compound different from a single bond.

[0177] More preferred compounds of Formulas M1 - M32 are those in which, in the formula, these groups Sp different from a single bond 1 and Sp 2 and Sp 3 are -(CH 2 ) s1 -X”-(where s1 is an integer from 1 to 6, preferably 2, 3, 4 or 5, X” is a linkage to a benzene ring, and is -O-, -O-CO-, -CO-O, -O-CO-O- or a single bond). It is a compound represented by.

[0178] More preferred compounds of Formulas M1 - M32 are those selected from Table D below.

[0179] An LC medium containing one, two or three polymerizable compounds selected from Formula M, preferably Formulas M1 - M32, is particularly preferred.

[0180] Preferably, the proportion of the polymerizable compounds including those of Formula M and its sub - formulas in the LC medium is 0.01 - 5%, very preferably 0.05 - 1%, and most preferably 0.1 - 0.5%.

[0181] It has been observed that by adding one or more polymerizable compounds of formula M to an LC medium, advantageous properties such as fast response times can be obtained. Such LC media are particularly suitable for use in PSA displays exhibiting low image sticking, rapid and complete polymerization, rapid generation of a stable low pretilt angle after UV exposure, high reliability, high VHR values after UV exposure, and high birefringence. By appropriate selection of the polymerizable compound, it is possible to increase the absorption of the LC medium at longer UV wavelengths, so that such longer UV wavelengths can be used for polymerization, which is advantageous for the manufacturing process of the display.

[0182] The polymerizable group P is, for example, suitable for polymerization reactions such as free radical or ionic chain polymerization, polyaddition or polycondensation, or for polymer-analogous reactions such as addition or condensation onto the main chain. Groups suitable for chain polymerization, in particular those containing a C=C double bond or a -C≡C- triple bond, and groups suitable for ring-opening polymerization such as, for example, oxetane or epoxide groups, are particularly preferred.

[0183] Preferred group P is CH 2 =CW 1 -CO-O-, CH 2 =CW 1 -CO-,

[0184]

Chemical formula

[0185] A highly preferred group P is CH 2 =CW 1 -CO-O-, CH 2 =CW 1 -CO-,

[0186]

Chemical formula

[0187] A very particularly preferred group P is CH 2 =CW 1 -CO-O-, in particular CH 2 =CH-CO-O-, CH 2 =C(CH 3 )-CO-O- and CH 2 =CF-CO-O-, furthermore CH 2 =CH-O-, (CH 2 =CH) 2 CH-O-CO-, (CH 2 =CH) 2 CH-O-,

[0188]

Chemical formula

[0189] An even more preferred polymerizable group P is selected from the group consisting of vinyloxy, acrylate, methacrylate, fluoroacrylate, chloroacrylate, oxetane and epoxide, and most preferably selected from acrylate and methacrylate.

[0190] If Sp is different from a single bond, it is preferably of the formula Sp”-X”, and as a result each group P-Sp- corresponds to the formula P-Sp”-X”-, in which Sp” represents an alkylene having 1 to 20, preferably 1 to 12 C atoms, and the group may optionally be mono- or polysubstituted by F, Cl, Br, I or CN, provided that in addition, one or more non-adjacent CH 2 groups, independently of one another, are each replaced by -O-, -S-, -NH-, -N(R 0 )-, -Si(R 0 R 00 )-, -CO-, -CO-O-, -O-CO-, -O-CO-O-, -S-CO-, -CO-S-, -N(R 00 )-CO-O-, -O-CO-N(R 0 )-, -N(R 0 )-CO-N(R 00 )-, -CH=CH- or -C≡C- so that O and / or S atoms are not directly linked to each other, 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 )-, -OCH 2 -, -CH 2 O-, -SCH 2 -, -CH 2 S-, -CF 2 O-, -OCF 2 -, -CF 2 S-, -SCF 2 -, -CF 2 CH 2 -, -CH 2 CF 2 -, -CF 2 CF 2 -, -CH=N-, -N=CH-, -N=N-, -CH=CR 0 -, -CY 2 =CY 3 -, -C≡C-, -CH=CH-CO-O-, -O-CO-CH=CH- or a single bond, R 0and R 00 each independently represents H or an alkyl having 1 to 20 C atoms, Y 2 and Y 3 each independently represents H, F, Cl or CN.

[0191] 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.

[0192] Typical spacer groups Sp and -Sp”-X”- are, for example, -(CH 2 ) p1 -, -(CH 2 CH 2 O) q1 -CH 2 CH 2 -, -CH 2 CH 2 -S-CH 2 CH 2 -, -CH 2 CH 2 -NH-CH 2 CH 2 - or -(SiR 0 R 00 -O) p1 -, where p1 is an integer from 1 to 12 and q1 is an integer from 1 to 3, and R 0 and R 00 have the meanings shown above.

[0193] Particularly preferred groups Sp and -Sp”-X”- are -(CH 2 ) p1 -, -(CH 2 ) p1 -O-, -(CH 2 ) p1 -O-CO-, -(CH 2 ) p1 -CO-O-, -(CH 2 ) p1-O-CO-O-, where p1 and q1 have the meanings given above.

[0194] Particularly preferred groups Sp” are, in each case, linear ethylene, propylene, butylene, pentylene, hexylene, heptylene, octylene, nonylene, decylene, undecylene, dodecylene, octadecylene, ethyleneoxyethylene, methylenoxybutylene, ethylenethioethylene, ethylene-N-methyliminoethylene, 1-methylalkylene, ethenylene, propenylene and butenylene.

[0195] For the production of a PSA display, the polymerizable compound contained in the LC medium is polymerized or (when one compound contains two or more polymerizable groups) crosslinked in situ in the LC medium between the substrates of the LC display, optionally while applying a voltage to the electrodes.

[0196] The structure of the PSA display according to the present invention corresponds to the normal configuration of a PSA display as described in the prior art cited at the beginning. A configuration without protrusions is preferred, and in particular, further, it is preferred that the electrode on the color filter side is not structured and only the electrode on the TFT side has slots. An electrode structure particularly suitable and preferred for a PS-VA display is described, for example, in US Patent Application Publication No. 2006 / 0066793.

[0197] By combining the compounds of the above preferred embodiments with the above polymerizable compounds, in the LC medium according to the present invention, a high clearing point and a high VHR value are always obtained simultaneously with a low threshold voltage, a low rotational viscosity and very good low temperature stability.

[0198] By using an LC medium containing a polymerizable compound, a particularly low pretilt angle is rapidly established in a PSA display. In particular, the LC medium also shows that the response time in a PSA display, particularly the response time of intermediate gradations, is significantly shortened compared to media from the prior art.

[0199] An LC medium having a nematic liquid crystal phase and preferably not having a chiral liquid crystal phase is generally preferred.

[0200] The present invention also relates to the use of an LC medium according to the invention as described above and below for electro-optical purposes, in particular for use in shutter glass, and for 3D applications in IPS, PS-IPS, FFS, PS-FFS, HB-FFS, U-IPS, TN, PS-TN, STN or TN-TFT displays, and to electro-optical displays, in particular those of the types mentioned above, comprising an LC medium according to the invention as described above and below, in particular IPS, PS-IPS, FFS, PS-FFS, HB-FFS, U-IPS, TN, PS-TN, STN or TN-TFT displays.

[0201] The present invention also relates to electro-optical displays, such as STN or MLC displays, having two flat parallel outer plates that form a cell together with a frame, integrated non-linear elements for switching individual pixels on the outer plates, and a nematic LC mixture disposed in the cell and having positive dielectric anisotropy and high resistivity, provided that the nematic LC mixture is an LC medium according to the invention as described above and below.

[0202] The LC medium according to the invention enables a significant expansion of the range of available parameters. The achievable combination of clearing point, viscosity at low temperatures, thermal and UV stability and high optical anisotropy is far superior to prior art precursor materials.

[0203] The LC medium according to the invention is suitable for portable applications such as mobile phones and PDAs and TFT applications. Furthermore, the LC medium according to the invention is particularly suitable for use in FFS and IPS displays.

[0204] The LC medium according to the invention preferably retains the nematic phase up to -20 °C, very preferably up to -30 °C and most preferably up to -40 °C. The LC medium according to the invention has a clearing point of preferably 85 °C or higher, very preferably 95 °C or higher and most preferably 105 °C or higher.

[0205] The LC medium according to the present invention preferably has a rotational viscosity γ of 130 mPa·s or less, more preferably 115 mPa·s or less, 1 and an excellent MLC display with a fast response time can be achieved. The rotational viscosity is determined at 20°C.

[0206] In a preferred embodiment, the dielectric anisotropy at 20°C of the LC medium according to the present invention is preferably +4 or more, more preferably +6 or more, and most preferably +8 or more.

[0207] The birefringence Δn at 20°C of the LC medium according to the present invention is preferably in the range of 0.080 to 0.150, more preferably 0.090 to 0.140, and particularly preferably 0.100 to 0.130.

[0208] The range of the nematic phase of the LC medium according to the present invention preferably has a width of at least 100°, more preferably at least 110°C, and particularly preferably at least 130°. This range preferably extends from at least -25°C to +105°C.

[0209] Needless to say, by appropriate selection of the components of the LC mixture according to the present invention, it is also possible to achieve a higher clearing point (e.g., exceeding 100 °C) at a higher threshold voltage or a lower clearing point at a lower threshold voltage while retaining other advantageous properties. Correspondingly, it is likewise possible to obtain a mixture having a higher Δε and thus a lower threshold with only a slightly increased viscosity. The MLC display according to the present invention preferably operates at the first transmission minimum of Gooch and Tarry [C.H. Gooch and H.A. Tarry, Electron. Lett. Vol. 10, pp. 2 - 4, 1974; C.H. Gooch and H.A. Tarry, Appl. Phys. Vol. 8, pp. 1575 - 1584, 1975], in which case, in addition to particularly favorable electro - optical properties such as a high steepness of the characteristic curve and a low angular dependence of the contrast (German Patent No. 30 22 818), a lower dielectric anisotropy is sufficient to obtain the same threshold voltage as a similar display at the second minimum. For this reason, by using the mixture according to the present invention at the first minimum, it is possible to achieve a significantly higher resistivity value than when the mixture contains a cyano compound. Through appropriate selection of the individual components and their weight ratios, one skilled in the art can set the birefringence required for a pre - specified layer thickness of the MLC display using simple conventional methods.

[0210] Measurement of the voltage holding ratio (HR) [S. Matsumoto et al., Liquid Crystals, Vol. 5, p. 1320 (1989); K. Niwa et al., Proc. SID Conference, San Francisco, June 1984, p. 304 (1984); G. Weber et al., Liquid Crystals, Vol. 5, p. 1381 (1989)] is carried out according to the following formula

[0211]

Chemical formula

[0212]

Chemical formula

[0213] The LC media according to the invention have very good light and UV stability, i.e., they show a significantly small decrease in HR upon exposure to light, heat or UV.

[0214] The construction of the MLC display according to the invention from a polarizing plate, an electrode substrate and a surface-treated electrode corresponds to the normal design of this type of display. In this specification, the term normal design is meant in a broad sense and encompasses all derivatives and modifications of MLC displays, in particular also matrix display elements based on polycrystalline silicon TFTs or MIMs.

[0215] However, a major difference between the display according to the invention and the hitherto conventional displays based on twisted nematic cells lies in the selection of the liquid crystal parameters of the liquid crystal layer.

[0216] The LC media which can be used according to the invention are prepared in a conventional manner per se, for example by mixing one or more compounds of claim 1 with one or more compounds of the formulae IV to XXX and / or with further liquid crystal compounds and / or additives. Generally, the desired amounts of the components used in smaller amounts are advantageously dissolved in the components constituting the main composition by heating. It is also possible to mix solutions of the components in an organic solvent, for example acetone, chloroform or methanol, and after complete mixing, to remove the solvent again, for example by distillation.

[0217] The LC medium may also contain further additives known to those skilled in the art and described in the literature, such as, for example, polymerization initiators, inhibitors, surfactants, light stabilizers, antioxidants such as BHT, TEMPOL, fine particles, free radical scavengers, nanoparticles, etc. For example, 0 to 15% of a dichroic dye or a chiral dopant or an initiator such as Irgacure651® or Irgacure907® can be added. Suitable stabilizers and dopants are described in Tables C and D below.

[0218] In a preferred embodiment, the LC medium preferably contains one or more chiral dopants at a concentration of 0.01 to 1% by weight, very preferably 0.05 to 0.5% by weight. The chiral dopant is preferably selected from the group consisting of compounds from Table B below, very preferably from the group consisting of R- or S-1011, R- or S-2011, R- or S-3011, R- or S-4011, and R- or S-5011.

[0219] In another preferred embodiment, the LC medium contains a racemate of one or more chiral dopants, preferably selected from the chiral dopants described in the previous paragraph.

[0220] In another preferred embodiment of the present invention, the LC medium contains one or more further stabilizers, preferably selected from the group consisting of the following formulas.

[0221]

Chemical formula

[0222]

Chemical formula

[0223] The preferred stabilizers of formula S3 are selected from formula S3A.

[0224]

Chemical formula

[0225] Highly preferred stabilizers are selected from the group consisting of the following formulas.

[0226]

Chemical formula

[0227]

Chemical formula

[0228]

Chemical formula

[0229]

Chemical formula

[0230] In a preferred embodiment, the LC medium comprises one or more stabilizers selected from the group consisting of formulas S1-1, S2-1, S3-1, S3-1 and S3-3.

[0231] In a preferred embodiment, the LC medium comprises one or more stabilizers selected from Table D.

[0232] Preferably, the proportion of the stabilizer in the LC medium, such as those of Formulas S1 - S3, is 10 - 500 ppm, and very preferably 20 - 100 ppm.

[0233] In another preferred embodiment, the LC medium according to the present invention preferably contains a self-aligning (SA) additive at a concentration of 0.1 - 2.5%.

[0234] The preferred SA additive for use in this preferred embodiment is selected from compounds containing 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.

[0235] More preferably, the SA additive contains one or more polymerizable groups optionally linked to the mesogenic group via a spacer group. These polymerizable SA additives can be polymerized in the LC medium under the same conditions as applied to the RM in the PSA process.

[0236] Suitable SA additives are disclosed, for example, in US Patent Application Publication Nos. 2013 / 0182202, 2014 / 0838581, 2015 / 0166890, and 2015 / 0252265.

[0237] In another preferred embodiment, the LC medium or polymer-stabilized display according to the present invention contains one or more self-aligning additives selected from Table E below.

[0238] In a preferred embodiment, the display according to the present invention does not include an alignment layer.

[0239] Furthermore, for example, 0 to 15% by weight of a dichroic dye, furthermore, nanoparticles, a conductive salt for improving conductivity, preferably ethyl dimethyldodecylammonium 4-hexyloxybenzoate, tetrabutylammonium tetraphenylborate or a complex salt of crown ether (see, for example, Haller et al., Mol. Cryst. Liq. Cryst. Vol. 24, pp. 249-258 (1973)), or a substance for modifying the dielectric anisotropy, viscosity and / or orientation of the nematic phase can also be added to the LC medium. Substances of this type are described, for example, in German Patent Application Publication No. 22 09 127, German Patent Application Publication No. 22 40 864, German Patent Application Publication No. 23 21 632, German Patent Application Publication No. 23 38 281, German Patent Application Publication No. 24 50 088, German Patent Application Publication No. 26 37 430 and German Patent Application Publication No. 28 53 728.

[0240] In the present application and the following examples, the structure of the LC compound is indicated by an acronym and converted into a chemical formula according to Table A. All groups C n H 2n+1 and C m H 2m+1 are linear alkyl groups having n and m carbon atoms, respectively; n, m and k are integers, preferably representing 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12. The codes in Table B are self-explanatory. In Table A, only the acronyms of the parent structures are shown. In individual cases, the codes for the substituents R 1* 、R 2* 、L 1* and L 2* follow separated by dashes.

[0241]

Table 1

[0242] Preferred mixture components are shown in Tables A and B.

[0243]

Table 2

[0244]

Table 3

[0245]

Table 4

[0246]

Table 5

[0247]

Table 6

[0248]

Table 7

[0249]

Table 8

[0250]

Table 9

[0251]

Table 10

[0252]

Table 11

[0253]

Table 12

[0254] In addition to the compound of Formula I, an LC medium containing at least one, two, three, four or more compounds from Table B is particularly preferred.

[0255] [Table 13]

[0256] [Table 14]

[0257] [Table 15]

[0258] [Table 16]

[0259] [Table 17]

[0260] [Table 18]

[0261] [Table 19]

[0262] [Table 20]

[0263] [Table 21]

[0264]

Table 22

[0265]

Table 23

[0266]

Table 24

[0267]

Table 25

[0268]

Table 26

[0269]

Table 27

[0270]

Table 28

[0271]

Table 29

[0272]

Table 30

[0273]

Table 31

[0274]

Table 32

[0275]

Table 33

[0276]

Table 34

[0277]

Table 35

[0278]

Table 36

[0279]

Table 37

[0280]

Table 38

[0281]

Table 39

[0282]

Table 40

[0283]

Table 41

[0284]

Table 42

[0285] In a preferred embodiment, the LC medium according to the present invention preferably contains one or more polymerizable compounds selected from the polymerizable compounds of Formulas RM-1 to RM-143. Among these, compounds RM-1, RM-4, RM-8, RM-17, RM-19, RM-35, RM-37, RM-39, RM-40, RM-41, RM-48, RM-52, RM-54, RM-57, RM-64, RM-74, RM-76, RM-88, RM-102, RM-103, RM-109, RM-117, RM-120, RM-121 and RM-122 are particularly preferred.

[0286] [Table 43]

[0287] [Table 44]

[0288] [Table 45]

[0289] [Table 46]

[0290] [Table 47]

[0291] [Table 48]

[0292] [Table 49]

[0293]

Table 50

[0294]

Table 51

[0295]

Table 52

[0296]

Table 53

[0297]

Table 54

[0298]

Table 55

[0299] In a preferred embodiment, the LC medium and the display according to the present invention comprise one or more SA additives selected from Formulas SA-1 to SA-48, preferably Formulas SA-14 to SA-48, very preferably Formulas SA-20 to SA-34 and SA-48, preferably in combination with one or more RM of Formula M.

[0300] The following examples are intended to illustrate the present invention without limiting it.

[0301] Unless otherwise explicitly stated above and below, all percentage data represent weight percentages and relate to the corresponding mixture as a whole, including all solid or liquid components but excluding the solvent. Unless otherwise explicitly stated, all temperatures are given in degrees Celsius (°C). m.p. represents the melting point and cl.p. represents the clearing point. Further, C represents the crystalline state, N represents the nematic phase, S represents the smectic phase, and I represents the isotropic phase. Data between these symbols represent transition temperatures.

[0302] In addition, the following abbreviations and symbols are used: V 0 Voltage threshold at 20 °C [V] n e Anomalous refractive index at 20 °C and 589 nm n 0 Ordinary refractive index at 20 °C and 589 nm Δn Optical anisotropy at 20 °C and 589 nm ε ⊥ Dielectric permittivity perpendicular to the director at 20 °C and 1 kHz ε ∥ Dielectric permittivity parallel to the director at 20 °C and 1 kHz Δε Dielectric anisotropy at 20 °C and 1 kHz cl.p., T ni Clearing point [°C] γ 1 Rotational viscosity at 20 °C [mPa·s] K 1 Elastic constant for "splay" deformation at 20 °C [pN] K 2 Elastic constant for "twist" deformation at 20 °C [pN] K 3 Elastic constant for "bend" deformation at 20 °C [pN]

[0303] All physical properties are determined in accordance with "Merck Liquid Crystals, Physical Properties of Liquid Crystals", November 1997, Merck KGaA, Germany, and a temperature of 20 °C applies in each case unless otherwise explicitly indicated.

[0304] For the present invention, unless otherwise explicitly indicated, the term "threshold voltage" refers to the capacitance threshold (V 0 ), also known as the Frederiks threshold. Also, in examples, although generally normal, the optical threshold for 10% relative contrast (V 10 ) may also be shown.

Example

[0305] <Comparative Example 1> Prepare LC mixture C1 as follows.

[0306]

Table 56

[0307] Add 0.05% of stabilizer S2-1 to 99.95% of mixture C1.

[0308]

Chemical formula

[0309] Add 0.05% of stabilizer S2-1 and 0.1% of stabilizer S3-1 to 99.85% of the obtained LC mixture to give mixture C11.

[0310]

Chemical formula

[0311] <Example 1> Prepare LC mixture N1 as follows.

[0312]

Table 57

[0313] The mixture contains 1.0% of the compound CPGP-5-2 of formula I.

[0314] Add 0.1% of stabilizer S3-1 to 99.9% of mixture N1 to give mixture N11.

[0315] <Example 2> Prepare the LC mixture N2 as follows.

[0316]

Table 58

[0317] The mixture contains 1.0% of the compound CPGP-5-2 of formula I.

[0318] Add 0.1% of stabilizer S3-1 to 99.9% of mixture N2 to give mixture N22.

[0319] <VHR value> Measure the VHR values of mixtures C11, N11 and N22 in a VHR test cell at 100 °C, 3 Hz and 1 V before and after light exposure using an LED lamp.

[0320] The results are shown in Table 1.

[0321]

Table 59

[0322] <Comparative Example 2> Prepare the LC mixture C2 as follows.

[0323]

Table 60

[0324] The mixture does not show satisfactory LTS.

[0325] <Example 3> Prepare the LC mixture N3 as follows.

[0326]

Table 61

[0327] The mixture contains 0.5% of the compound CPGP-5-2 of formula I.

[0328] <Example 4> Prepare the LC mixture N4 as follows.

[0329]

Table 62

[0330] The mixture contains 1.0% of the compound CPGP-5-2 of formula I and shows good LTS at -20°C.

[0331] <Example 5> Prepare the LC mixture N5 as follows.

[0332]

Table 63

[0333] The mixture contains 2.0% of the compound CPGP-5-2 of formula I and shows good LTS at -20°C.

[0334] <Example 6> Prepare the LC mixture N6 as follows.

[0335]

Table 64

[0336] The mixture contains 4.0% of the compound CPGP-5-2 of formula I and shows good LTS at -20°C and -30°C.

[0337] <Example 7> Prepare the LC mixture N7 as follows.

[0338]

Table 65

[0339] The mixture contains 6.0% of the compound CPGP-5-2 of formula I and exhibits good LTS at -20 °C, -30 °C and -40 °C.

[0340] <VHR value> Measure the VHR values of mixtures C2, N4, N5, N6 and N7 in a cell for VHR testing at 60 °C, 60 Hz / 3 Hz and 1 V before and after light exposure using various LED lamps.

[0341] The results are shown in Tables 2 and 3.

[0342]

Table 66

[0343]

Table 67

[0344] It can be seen from Tables 2 and 3 that the mixtures N4 to N7 according to the invention containing the compound of formula I exhibit higher VHR values than mixture C2 after backlight loading.

[0345] <Example 8> Add 0.05% of stabilizer S1-1 to 99.95% of the LC mixture of Example 7.

[0346]

Chemical formula

[0347] <Example 9> Add 0.05% of stabilizer S1-1 and 0.3% of monomer RM-1 to 99.65% of the LC mixture of Example 7.

[0348]

Chem.

[0349] <Example 10> To 99.7% of the LC mixture of Example 7, 0.3% of monomer RM-35 is added.

[0350]

Chem.

[0351] <Example 11> To 99.65% of the LC mixture of Example 7, 0.05% of stabilizer S2-1 and 0.3% of monomer RM-64 are added.

[0352]

Chem.

[0353] <Example 12> To 99.7% of the LC mixture of Example 6, 0.3% of monomer RM-120 is added.

[0354]

Chem.

[0355] <Example 13> To 99.699% of the LC mixture of Example 5, 0.3% of monomer RM-19 and 0.001% of Irgacure651 (registered trademark) are added.

[0356]

Chem.

[0357] <Example 14> To 99.7% of the LC mixture of Example 4, 0.3% of monomer RM-121 is added.

[0358]

Chem.

[0359] <Example 15> To 99.7% of the LC mixture of Example 6, 0.3% of monomer RM-122 is added.

[0360]

Chem.

[0361] <Example 16> To 99.7% of the LC mixture of Example 7, 0.3% of monomer RM-91 is added.

[0362]

Chem.

[0363] <Example 17> To 99.98% of the LC mixture of Example 7, 0.02% of stabilizer S1-1 is added.

[0364] <Example 18> To 99.99% of the LC mixture of Example 7, 0.01% of stabilizer S2-1 is added.

[0365]

Chem.

[0366] <Example 19> To 99.98% of the LC mixture of Example 3, 0.02% of stabilizer 3-1 is added.

[0367]

Chem.

[0368] <Example 20> Add 0.05% of stabilizer S3-2 to 99.95% of the LC mixture of Example 6.

[0369]

Chem.

[0370] <Example 21> Add 0.02% of stabilizer S3-3 to 99.98% of the LC mixture of Example 7.

[0371]

Chem.

[0372] <Example 22> Add 0.3% of monomer RM-39 to 99.7% of the LC mixture of Example 4.

[0373]

Chem.

Claims

1. An LC medium having positive dielectric anisotropy, comprising more than 0% and 10% or less of one or more compounds of formula I, one or more compounds of formula XII, and no compounds of formulae XIIIa, XIIIb and XIV. 【Chemical 1】 (In the formula, R １ and R ２ each independently represents an alkyl having 1 to 6 carbon atoms.) 【Chemical 2】 (In the formula, X0 represents F, Cl, CN, SF5, SCN, NCS, a halogenated alkyl group having up to 6 C atoms, a halogenated alkenyl group, a halogenated alkoxy group or a halogenated alkenyloxy group, "alkenyl" represents C2-6-alkenyl, L represents H or F.) [Chemical Formula 3] (In the formula, L1 and L2 each independently represent H or F, R' represents alkyl or alkoxy having 1 to 12 C atoms, which may be the same or different in each occurrence, R" represents alkenyl having 2 to 7 C atoms and including a terminal vinyl group, which may be the same or different in each occurrence, R''' represents R' or R".)

2. The LC medium according to claim 1, characterized by having a birefringence of less than 0.

15.

3. The LC medium according to claim 1 or 2, characterized by comprising one or more compounds of formula I selected from the following sub-formulae. 【Chemical Formula 4】

4. The LC medium according to any one of claims 1 to 3, characterized in that the concentration of the compound of formula I or its sub-formula in the LC medium is 1.0 to 10%.

5. The LC medium according to any one of claims 1 to 4, characterized by comprising a compound of sub-formula XIIa as the compound of formula XII. [Chemical Formula 5]

6. The LC medium according to any one of claims 1 to 5, characterized by additionally comprising one or more compounds selected from the following formulae. 【Chemical Formula 6】 (In the formula, the individual groups may each independently be replaced by -O-, -CO-O- or -O-CO- in each occurrence, 【Chemical Formula 7】 R ０ An unsubstituted or halogenated alkyl or alkoxy group having 1 to 15 carbon atoms, provided that in addition, one or more CH ２ groups, each independently of one another, are such that O atoms are not directly linked to one another, and are -C≡C-, -CF ２ O-, -CH=CH-, [Chemical Formula 8] or represents, 【Chemical Formula 9】 X ０ F, Cl, CN, SF ５ , SCN, NCS, a halogenated alkyl group having up to 6 C atoms, a halogenated alkenyl group, a halogenated alkoxy group or a halogenated alkenyloxy group, Y ０ H or CH ３ , Y １～６ H or F.)

7. The LC medium according to any one of claims 1 to 6, characterized by comprising one or more compounds selected from the group consisting of the following sub-formulae. 【Chemical 10】 【Chemical 11】 (In the formula, R ０ and X ０ have the meaning given in claim 6.)

8. The LC medium according to any one of claims 1 to 7, characterized by comprising one or more compounds selected from the group consisting of the following sub-formulae. 【Chemical Formula 12】 【Chemical 13】 【Chemical Formula 14】 【Chemical Formula 15】 【Chemical 16】 (In the formula, R ０ and X ０ have the meaning given in claim 6.)

9. The LC medium according to any one of claims 1 to 8, further comprising one or more compounds selected from the group consisting of the following formulas. 【Chemical 17】 【Chemical 18】 (In the formula, R ０ , X ０ and Y １～４ have the meaning given in claim 6, Z ０ is -C ２ H ４ -, -(CH ２ ) ４ -, -CH=CH-, -CF=CF-, -C ２ F ４ -, --CH ２ CF ２ -, -CF ２ CH ２ -, -CH ２ O-, -OCH ２ -, -COO- or -OCF ２ -, and in Formulas V and VI also a single bond, and in Formulas V and VIII also -CF ２ O- also represents, r represents 0 or 1, s represents 0 or 1.)

10. The LC medium according to any one of claims 1 to 9, comprising one or more compounds selected from the group consisting of the following formulas. 【Chemical 19】 【Chemical 20】 (In the formula, R ０ has the meaning given in claim 6.)

11. The LC medium according to any one of claims 1 to 10, further comprising one or more compounds selected from the following formulas. 【Chemical 21】 (In the formula, "alkyl" represents C １～６ -alkyl, "alkenyl" represents C ２～６ -alkenyl, "R” is C １～６ -alkyl, C １～６ -alkoxy or C ２～６ -alkenyl, and represents R ａ１ 、R ｂ１ each independently represents CH ３ or C ２ H ５ and i and k are each independently 0, 1, 2, or 3.)

12. The LC medium according to any one of claims 1 to 11, comprising one or more compounds selected from the following sub-formulas. 【Chemical 22】 (In the formula, "alkyl" has the meaning given in claim 11.)

13. The LC medium according to any one of claims 1 to 12, comprising one or more compounds of formula XXX. 【Chemical 23】 (In the formula, R3 and R4 each independently represent n-alkyl, alkoxy, oxaalkyl, fluoroalkyl, or alkenyl having up to 6 carbon atoms.)

14. The LC medium according to any one of claims 1 to 13, further comprising one or more compounds selected from the following formulas. 【Chemical 24】 (In the formula, R ３ and R ４ each independently represents an n-alkyl, alkoxy, oxaalkyl, fluoroalkyl or alkenyl having up to 6 carbon atoms each.

15. The LC medium according to any one of claims 1 to 14, further comprising one or more compounds selected from the following sub-formulas. 【Chemical 25】 (In the formula, "alkyl" has the meaning given in claim 11.)

16. The LC medium according to any one of claims 1 to 15, comprising one or more compounds of formula XVI. 【Chemical 26】 (In the formula, R ３ and R ４ have the meaning given in claim 13, L represents H or F.)

17. The LC medium according to any one of claims 1 to 16, comprising one or more compounds of formula XVIc2. 【Chemical 27】

18. The LC medium according to any one of claims 1 to 17, comprising one or more compounds of formula IA1. 【Chemical Formula 28】 (In the formula, R ０ is ethyl or propyl, and X ０ is F.)

19. The LC medium according to any one of claims 1 to 18, comprising one or more compounds selected from the group consisting of the compounds of the following formula. 【Chemical 29】 【Chemical Formula 30】 (In the formula, R ０ , X ０ and Y １～４ each independently has one of the meanings given in claim 6.)

20. The LC medium according to any one of claims 1 to 19, comprising one or more compounds of formula XXIa. 【Chemical 31】 (In the formula, R ０ represents ethyl, n-propyl, n-butyl, and n-pentyl.)

21. The LC medium according to any one of claims 1 to 20, characterized by containing one or more compounds selected from the group of compounds of the following formula. 【Chemical Formula 32】 (In the formula, R ３ has the meaning shown in claim 13, X ０ has the meaning shown in claim 6.)

22. The LC medium according to any one of claims 1 to 21, characterized by containing one or more compounds of formula XXIXa. 【Chemical 33】 (In the formula, R ３ represents ethyl, n-propyl, n-butyl, and n-pentyl.)

23. A method for preparing the LC medium according to any one of claims 1 to 22, comprising one or more compounds of formula I or its sub-formulas as defined in claim 1 or 3, and one or more compounds of formula XII as defined in claim 1 or sub-formula XIIa as defined in claim 5, and one or more compounds or further LC compounds as defined in any one of claims 4 to 22, characterized by mixing them.

24. Use of the LC medium according to any one of claims 1 to 22 for electro-optical purposes.

25. Use according to claim 24, for 3D applications in shutter glasses or in IPS, PS-IPS, FFS, PS-FFS, HB-FFS, U-IPS, TN, PS-TN, STN or TN-TFT displays.

26. An LC display comprising the LC medium according to any one of claims 1 to 22.

27. The LC display according to claim 26, which is an IPS, PS-IPS, FFS, PS-FFS, HB-FFS, U-IPS, TN, PS-TN, STN or TN-TFT display.

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