Liquid-crystalline medium

Abstract

The invention relates to a liquid-crystalline medium and to the use thereof for an active-matrix display, in particular based on the VA, PSA, PS-VA, PM-VA, SS-VA, PALC, IPS, PS-IPS, FFS or PS-FFS effect.

1 . A liquid-crystalline medium comprising:
 a compound of the formula I1 and/or a compound of the formula I2   
       
         
           
           
               
               
           
         
         one or more compounds of formula EY 
       
       
         
           
           
               
               
           
         
         
           in which the individual radicals each, independently of one another, and identically or differently on each occurrence, have one of the following meanings: 
           R 1  and R 1*  denote H, an alkyl or alkenyl radical having up to 15 C atoms which is unsubstituted, monosubstituted by CN or CF 3  or at least monosubstituted by halogen, where, in addition, one or more CH 2  groups in these radicals may each be replaced by —O—, —S—, 
         
       
       
         
           
           
               
               
           
         
         
            —C≡C—, —CF 2 O—, —OCF 2 —, —OC—O— or —O—CO— in such a way that O atoms are not linked directly to one another, or a cycloalkyl ring having 3 to 6 C atoms, 
           L 1  and L 2  denote F, Cl, CF 3  or CHF 2 , 
           with the proviso that the liquid-crystalline medium does not comprise a compound of the formula I3, 
         
       
       
         
           
           
               
               
           
         
       
       and
 one or more compounds selected from the group of the compounds of formulae BC, CR, PH-1, PH-2, BF-1, BF-2, BS-1 and BS-2 
 
       
         
           
           
               
               
           
         
         in which
 R B1 , R B2 , R CR1 , R CR2 , R 1 , and R 2  each, independently of one another, denote H, an alkyl or alkenyl radical having up to 15 C atoms which is unsubstituted, monosubstituted by CN or CF 3  or at least monosubstituted by halogen, where, in addition, one or more CH 2  groups in these radicals may each be replaced by —O—, —S—, 
 
       
       
         
           
           
               
               
           
         
         
            —C≡C—, —CF 2 O—, —OCF 2 —, —OC—O— or —O—CO— in such a way that O atoms are not linked directly to one another, 
           c denotes 0, 1 or 2, and 
           d denotes 1 or 2. 
         
       
     
     
         2 . A liquid-crystalline medium according to  claim 1 , wherein said one or more compounds of formula EY are selected from the group of compounds of the following formulae: 
       
         
           
           
               
               
           
         
         
           
           
               
               
           
         
         
           
           
               
               
           
         
       
     
     
         3 . A liquid-crystalline medium according to  claim 1 , further comprising one or more compounds selected from the group of compounds of formulae IIA, IIB and IIC, 
       
         
           
           
               
               
           
         
         in which 
         R 2A , R 2B  and R 2C  each, independently of one another, denote H, an alkyl or alkenyl radical having up to 15 C atoms which is unsubstituted, monosubstituted by CN or CF 3  or at least monosubstituted by halogen, where, in addition, one or more CH 2  groups in these radicals may each be replaced by —O—, —S—, 
       
       
         
           
           
               
               
           
         
          —C≡C—, —CF 2 O—, OCF 2 , —OC—O— or —O—CO— in such a way that O atoms are not linked directly to one another, 
         L 1-4  each, independently of one another, denote F or Cl, 
         Z 2  and Z 2′  each, independently of one another, denote a single bond, —CH 2 CH 2 —, —CH═CH—, —CF 2 O—, —OCF 2 —, —CH 2 O—, —OCH 2 —, —COO—, —OCO—, —C 2 F 4 , —CF═CF—, or —CH═CHCH 2 O—, 
         p denotes 1 or 2, 
         q denotes 0 or 1, and 
         v denotes an integer from 1 to 6. 
       
     
     
         4 . A liquid-crystalline medium according to  claim 1 , wherein said medium additionally comprises one or more compounds of formula III, 
       
         
           
           
               
               
           
         
       
       in which
 R 31  and R 32  each, independently of one another, denote a straight-chain alkyl, alkoxyalkyl or alkoxy radical having up to 12 C atoms, 
 
       
         
           
           
               
               
           
         
         denotes 
       
       
         
           
           
               
               
           
         
       
       and
 Z 3  denotes a single bond, —CH 2 CH 2 —, —CH═CH—, —CF 2 O—, —OCF 2 —, —CH 2 O—, —OCH 2 —, —COO—, —OCO—, —C 2 F 4 —, —C 4 H 9 —, or —CF═CF—. 
 
     
     
         5 . A liquid-crystalline medium according to  claim 1 , wherein said medium additionally comprises one or more terphenyls of formulae T-1 to T-21, 
       
         
           
           
               
               
           
         
         
           
           
               
               
           
         
         
           
           
               
               
           
         
         in which 
         R denotes a straight-chain alkyl or alkoxy radical having 1-7 C atoms or a straight-chain alkenyl radical having 2-7 C atoms, 
         m denotes 0, 1, 2, 3, 4, 5 or 6, 
         n denotes 0, 1, 2, 3 or 4, and 
         (O) denotes an oxygen atom or a single bond. 
       
     
     
         6 . A liquid-crystalline medium according to  claim 1 , wherein said medium additionally comprises one or more compounds of formulae O-1 to O-17, 
       
         
           
           
               
               
           
         
         
           
           
               
               
           
         
         in which
 R 1  and R 2  each, independently of one another, denote H, an alkyl or alkenyl radical having up to 15 C atoms which is unsubstituted, monosubstituted by CN or CF 3  or at least monosubstituted by halogen, where, in addition, one or more CH 2  groups in these radicals may each be replaced by —O—, —S—, 
 
       
       
         
           
           
               
               
           
         
          —C≡C—, —CF 2 O—, —OCF 2 —, —OC—O— or —O—CO— in such a way that O atoms are not linked directly to one another, and 
         the compounds of the formula O-17 are not identical with the compounds of the formulae I1 and I2. 
       
     
     
         7 . A liquid-crystalline medium according  claim 1 , wherein said medium additionally comprises one or more indane compounds of formula In, 
       
         
           
           
               
               
           
         
         in which
 R 11 , R 12 , R 13  denote a straight-chain alkyl, alkoxy, alkoxyalkyl or alkenyl radical having 1-6 or 2-6 C atoms respectively, 
 R 12  and R 13  additionally may also denote halogen, 
 
       
       
         
           
           
               
               
           
         
       
       denotes 
       
         
           
           
               
               
           
         
         
           i denotes 0, 1 or 2. 
         
       
     
     
         8 . A liquid-crystalline medium according to  claim 1 , wherein said medium additionally comprises one or more biphenyls selected from formulae B-1a, B-2a, B-2b, and B-2c: 
       
         
           
           
               
               
           
         
         in which alkyl* denotes an alkyl radical having 1-6 C atoms. 
       
     
     
         9 . A liquid-crystalline medium according to  claim 1 , wherein said medium additionally comprises one or more compounds selected from the group of the following compounds: 
       
         
           
           
               
               
           
         
       
     
     
         10 . A liquid-crystalline medium according to  claim 1 , wherein said medium additionally comprises one or more compounds selected from the group of the following compounds: 
       
         
           
           
               
               
           
         
       
     
     
         11 . A liquid-crystalline medium according to  claim 1 , wherein said medium comprises one or more compounds selected from the group of the compounds of formulae BF-1, BF-2, BS-1 and BS-2, 
       
         
           
           
               
               
           
         
         in which
 R 1 , and R 2  each, independently of one another, denote H, an alkyl or alkenyl radical having up to 15 C atoms which is unsubstituted, monosubstituted by CN or CH 3  or at least monosubstituted by halogen, where, in addition, one or more CH 2  groups in these radicals may each be replaced by —O—, —S—, 
 
       
       
         
           
           
               
               
           
         
         
            —C≡C—, —CF 2 O—, —OCF 2 —, —OC—O— or —O—CO— in such a way that O atoms are not linked directly to one another, 
           c denotes 0, 1 or 2, and 
           d denotes 1 or 2. 
         
       
     
     
         12 . A liquid-crystalline medium according to  claim 1 , wherein the proportion of compounds of the formulae I1 and I2 in the mixture as a whole is 5-30% by weight. 
     
     
         13 . A liquid-crystalline medium according to  claim 1 , wherein the proportion of compounds of the formulae I1 and 12 in the mixture is ≥3% by weight. 
     
     
         14 . A liquid-crystalline medium according to  claim 1 , wherein the proportion of compounds of the formula EY in the mixture as a whole is 3-20% by weight. 
     
     
         15 . A liquid-crystalline medium according to  claim 1 , wherein the proportion of compounds of the formula EY in the mixture is ≥2% by weight. 
     
     
         16 . A liquid-crystalline medium according to  claim 1 , wherein the proportion of compounds of the formulae I1, I2 and EY in the mixture as a whole is 10-35% by weight. 
     
     
         17 . A liquid-crystalline medium according to  claim 1 , wherein said medium further comprises at least one polymerizable compound. 
     
     
         18 . A liquid-crystalline medium according to  claim 1 , wherein said medium further comprises one or more additives selected from the group consisting of free-radical scavengers, antioxidants and UV stabilizers. 
     
     
         19 . A process for the preparation of a liquid-crystalline medium according  claim 1 , said process comprising:
 mixing a compound of the formulae I1 and I2 with at least one compound of the formula EY and one or more compounds of formulae BC, CR, PH-1, PH-2, BF-1, BF-2, BS-1 and BS-2, and optionally adding one or more additives and optionally at least one polymerizable compound.   
     
     
         20 . (canceled) 
     
     
         21 . An electro-optical display having active-matrix addressing, wherein said display contains, as dielectric, a liquid-crystalline medium according to  claim 1 . 
     
     
         22 . An electro-optical display according to  claim 21 , wherein said display is a VA, PSA, PS-VA, PM-VA, SS-VA, PALC, IPS, PS-IPS, FFS or PS-FFS display. 
     
     
         23 . A liquid-crystalline medium according to  claim 3 , wherein said medium contains one or more compounds of formula IIB. 
     
     
         24 . A liquid-crystalline medium according to  claim 1 , wherein R 1  and R 2  each, independently of one another, denote alkyl, alkoxy, alkenyl or alkenyloxy having 1 to 6 or 2 to 6 C atoms respectively. 
     
     
         25 . A liquid-crystalline medium according to  claim 11 , wherein R 1  and R 2  each, independently of one another, denote alkyl, alkoxy, alkenyl or alkenyloxy having 1 to 6 or 2 to 6 C atoms respectively.