Classifications

• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
  • C09K19/00—Liquid crystal materials
  • C09K19/04—Liquid crystal materials characterised by the chemical structure of the liquid crystal components, e.g. by a specific unit
  • C09K19/06—Non-steroidal liquid crystal compounds
  • C09K19/34—Non-steroidal liquid crystal compounds containing at least one heterocyclic ring
  • C09K19/3402—Non-steroidal liquid crystal compounds containing at least one heterocyclic ring having oxygen as hetero atom
  • C09K19/3405—Non-steroidal liquid crystal compounds containing at least one heterocyclic ring having oxygen as hetero atom the heterocyclic ring being a five-membered ring
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
  • C09K19/00—Liquid crystal materials
  • C09K19/04—Liquid crystal materials characterised by the chemical structure of the liquid crystal components, e.g. by a specific unit
  • C09K19/06—Non-steroidal liquid crystal compounds
  • C09K19/34—Non-steroidal liquid crystal compounds containing at least one heterocyclic ring
  • C09K19/3491—Non-steroidal liquid crystal compounds containing at least one heterocyclic ring having sulfur as hetero atom
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
  • C09K19/00—Liquid crystal materials
  • C09K19/04—Liquid crystal materials characterised by the chemical structure of the liquid crystal components, e.g. by a specific unit
  • C09K19/06—Non-steroidal liquid crystal compounds
  • C09K19/34—Non-steroidal liquid crystal compounds containing at least one heterocyclic ring
  • C09K19/3402—Non-steroidal liquid crystal compounds containing at least one heterocyclic ring having oxygen as hetero atom
  • C09K19/3405—Non-steroidal liquid crystal compounds containing at least one heterocyclic ring having oxygen as hetero atom the heterocyclic ring being a five-membered ring
  • C09K2019/3408—Five-membered ring with oxygen(s) in fused, bridged or spiro ring systems

Definitions

• the present invention relates to novel liquid crystalline media, in particular for use in liquid-crystal displays, and to these liquid-crystal displays, particularly to liquid-crystal displays which use the IPS (in-Djane switching) or, preferably, the FFS (fringe field switching) effect using dielectncally positive liquid crystals.
• the last one is also called SG-FFS (super grip FFS) effect occasionally.
• dielectncally positive liquid crystals are used, which comprise one or more compounds having at the same time a high dielectric constant parallel to the molecular director and perpendicular to the molecular director, leading to a large average dielectric constant and a high dielectric ratio.
• the liquid crystalline media optionally additionally comprise dielectncally negative, dielectncally neutral compounds or both.
• the liquid crystalline media are used in a
• liquid-crystal media according to the invention have a positive dielectric anisotropy and comprise compounds having at the same time large dielectric constants parallel and perpendicular to the molecular director.
• the media are distinguished by a particularly high transmission and reduced response time in respective displays, which is brought about by their unique combination of physical properties, especially by their dielectric properties and in particular by their high ratio of ( ⁇ / s av .) respectively of the high values of their dielectric ratio ( ⁇ / ⁇ ). This also leads to their excellent performance in the displays according to the invention.
• IPS and FFS displays using dielectncally positive liquid crystals are well known in the field and have been widely adopted for various types of displays like e.g. desk top monitors and TV sets, but also for mobile applications.
• IPS and in particular FFS displays using dielectncally negative liquid crystals are widely adopted.
• the latter ones are sometimes also called or UB-FFS (ultra bright FFS).
• UB-FFS ultra bright FFS
• Such displays are disclosed e.g. in US 2013/0207038 A1 . These displays are characterized by a markedly increased transmission compared to the previously used IPS- and FFS displays, which have been dielectrically positive liquid crystals.
• These displays using conventional, dielectrically negative liquid crystals however, have the severe disadvantage of requiring a higher operation voltage than the respective displays using dielectrically positive liquid crystals.
• Liquid crystalline media used for UB-FFS have a dielectric anisotropy of -0.5 or less and preferably of -1 .5 or less.
• Liquid crystalline media used for HB-FFS have a dielectric anisotropy of 0.5 or more and preferably of 1 .5 or more.
• Liquid crystalline media used for HB-FFS comprising both dielectrically negative and dielectrically positive liquid crystalline compounds, respectively mesogenic compounds are disclosed e.g. in US 2013/0207038 A1 . These media feature rather large values of ⁇ and of s av . already, however, their ratio of ( ⁇ / ⁇ ) is relatively small.
• the IPS or the FFS effect with dielectrically positive liquid crystalline media in a homogeneous alignment are preferred.
• LC phases which can be used industrially are required to have a liquid-crystalline mesophase in a suitable temperature range and low viscosity.
• TFTs comprising compound semiconductors, such as, for example, CdSe, or metal oxides like ZnO or TFTs based on polycrystalline and, inter alia, amorphous silicon.
• CdSe compound semiconductors
• metal oxides like ZnO metal oxides like ZnO
• TFTs based on polycrystalline and, inter alia, amorphous silicon The latter technology currently has the greatest commercial importance worldwide.
• the TFT matrix is applied to the inside of one glass plate of the display, while the other glass plate carries the transparent counter electrode on its inside. Compared with the size of the pixel electrode, the TFT is very small and has virtually no adverse effect on the image.
• This technology can also be extended to fully colour-capable displays, in which a mosaic of red, green and blue filters is arranged in such a way that a filter element is located opposite each switchable pixel.
• the TFT displays most used hitherto usually operate with crossed polaris- ers in transmission and are backlit.
• ECB or VAN cells or FFS cells
• monitors usually use IPS cells or TN (twisted nematic) cells
• notebooks, laptops and mobile applications usually use TN, VA or FFS cells.
• MLC displays of this type are particularly suitable for TV applications, monitors and notebooks or for displays with a high information density, for example in automobile manufacture or aircraft construction.
• problems regarding the angle dependence of the contrast and the response times difficulties also arise in MLC displays due to insufficiently high specific resistance of the liquid-crystal mixtures [TOGASHI, S., SEKIGUCHI, K., TANABE, H., YAMAMOTO, E., SORIMACHI, K., TAJIMA, E., WATA- NABE, H., SHIMIZU, H., Proc. Eurodisplay 84, Sept. 1984: A 210-288 Matrix LCD Controlled by Double Stage Diode Rings, pp.
• VAN vertical aligned nematic
• IPS displays for example: Yeo, S.D., Paper 15.3: "An LC Display for the TV Application", SID 2004 International Symposium, Digest of Technical Papers, XXXV, Book II, pp. 758 and 759
• TN displays as one of the three more recent types of liquid-crystal display that are currently the most important, in particular for television applications.
• MVA multi-domain vertical alignment, for example: Yoshide, H. et al., Paper 3.1 : "MVA LCD for Notebook or Mobile PCs SID 2004 International Symposium,
• ECB displays like ASV displays, use liquid-crystalline media having negative dielectric anisotropy ( ⁇ ), whereas TN and to date all conventional IPS displays use liquid-crystalline media having positive dielectric anisotropy.
• IPS and FFS displays utilizing dielectrically negative liquid crystalline media.
• liquid crystals are used as dielectrics, whose optical properties change reversibly on application of an elec- trical voltage.
• liquid-crystal media which are generally predominantly com- posed of liquid-crystal compounds, all of which have the same sign of the dielectric anisotropy and have the highest possible value of the dielectric anisotropy.
• at most relatively small proportions of neutral compounds and if possible no compounds having a sign of the dielectric anisotropy which is opposite to that of the medium are employed.
• liquid-crystal media having negative dielectric anisotropy e.g. for ECB or UB-FFS displays
• predominantly compounds having negative dielectric anisotropy are thus employed.
• the respective liquid-crystalline media employed generally consist predominantly and usually even essentially of liquid-crystal compounds having negative dielectric anisotropy.
• CN 104232105 A, WO 2014/192390 and WO 2015/007131 disclose liquid crystalline media with a positive dielectric anisotropy, some of which have a rather high dielectric constant perpendicular to the director.
• the phase range of the liquid-crystal mixture must be sufficiently broad for the intended application of the display.
• the response times of the liquid-crystal media in the displays also have to be improved, i.e. reduced. This is particularly important for displays for television or multimedia applications.
• optimise the rota- tional viscosity of the liquid-crystal media ( ⁇ ) i.e. to achieve media having the lowest possible rotational viscosity.
• the results achieved here are inadequate for many applications and therefore make it appear desirable to find further optimisation approaches.
• US 2016-0298033 (A) discloses, amongst others, the following
• Adequate stability of the media to extreme loads, in particular to UV exposure and heating, is very particularly important. In particular in the case of applications in displays in mobile equipment, such as, for example, mobile telephones, this may be crucial.
• the MLC displays disclosed hitherto have further disadvantages. These are e.g. their comparatively low contrast, their relatively high viewing-angle dependence and the difficulty in the reproduction of grey scales in these displays, especially when observed from an oblique viewing angle, as well as their inadequate VHR and their inadequate lifetime.
• the desired improvements of the transmission of the displays and of their response times are required in order to improve their energy efficiency, respectively their capacity to render rapidly moving pictures.
• MLC displays having very high specific resistance at the same time as a large working-temperature range, short response times and a low threshold voltage, with the aid of which various grey shades can be produced and which have, in particular, a good and stable VHR.
• the invention has the object of providing MLC displays, not only for monitor and TV applications, but also for mobile applications such as e.g.
• liquid-crystal displays which have, in particular in IPS and FFS displays, a low threshold voltage with short response times, a sufficiently broad nematic phase, favourable birefringence ( ⁇ ) and, at the same time, a high transmission, good stability to decomposition by heating and by UV exposure, and a stable, high VHR if use is made in these display elements of nematic liquid-crystal mixtures which comprise at least one compound, preferably two or more compounds of formula B, preferably selected from the group of the compounds of the sub-formulae B-1 and B-2, particularly preferably the sub-formula B-1 and/or B-2, more preferably both of formula B-1 and of formula B-2, and preferably additionally one or more compounds of formula I, preferably selected from the group of the compounds of the sub- formulae 1-1 and I-2, particularly preferably the sub-formula 1-1 and/or I-2, most preferably of formula I-2 and most preferably both of formula 1
• Media of this type can be used, in particular, for electro-optical displays having active-matrix addressing for IPS - or FFS displays.
• the invention thus relates to a liquid-crystalline medium on a mixture of polar compounds comprising one or more compounds having
• the ratio of the dielectric constant perpendicular to the director to the dielectric anisotropy ( ⁇ / ⁇ ) of 1 .0 or more corresponds to the ratio of the dielectric constant parallel ( ⁇ ) to the director to dielectric constant perpendicular ( ⁇ ) to the director, i.e. to the ratio of ( ⁇ / ⁇ ) of 2.0 or less.
• the media according to the present invention preferably additionally comprise a one or more compounds selected from the group of compounds of formulae II and III, preferably one or more compounds of formula II, more preferably in addition one or more compounds of formula III and, most preferably, additionally one or more compounds selected from the group of the compounds of formulae IV and V and, again preferably, one or more compounds selected from the group of compounds of formulae VI to IX (all formulae as defined below).
• the mixtures according to the invention exhibit very broad nematic phase ranges with clearing points > 70°C, very favourable values for the capaci- tive threshold, relatively high values for the holding ratio and at the same time good low-temperature stabilities at -20°C and -30°C, as well as very low rotational viscosities.
• the mixtures according to the invention are fur- thermore distinguished by a good ratio of clearing point and rotational viscosity and by a relatively high positive dielectric anisotropy.
• LCs of the FFS type using liquid crystals with positive dielectric anisotropy may be realised using specially selected liquid crystalline media. These media are characterised by a particular combination of physical properties. Most decisive amongst these are their dielectric properties and here a high average dielectric constant ( ⁇ av ), a high dielectric constant perpendicular to the director of the liquid crystal molecules ( ⁇ ) and, in particular, the relatively high ratio of these latter two values: ( ⁇ / ⁇ ).
• the liquid-crystalline media according to the present invention on the one hand, have a value of the dielectric anisotropy of 1 .5 or more, preferably of 3.5 or more preferably of 4.5 or more. At the other hand, they preferably have a dielectric anisotropy of 26 or less.
• liquid-crystalline media according to the present invention on the one hand, have a value of the dielectric constant perpendicular to the director of 2 or more, more preferably of 6 or more and, on the other hand preferably of 20 or less.
• the liquid crystalline media according to the present invention preferably have a dielectric ratio ( ⁇ / ⁇ ) of 2.0 or less, more preferably of 1 .5 or less and, most preferably, of 1 .0 or less.
• the liquid crystalline media according to the present invention in a preferred embodiment have a positive dielectric anisotropy, preferably in the range from 1 .5 or more to 20.0 or less, more preferably in the range from 3.0 or more to 8.0 or less and, most preferably in the range from 4.0 or more to 7.0. or less.
• the liquid crystalline media according to the present invention in a preferred embodiment, which may be the same as the preferred embodiment mentioned above, have a dielectric constant perpendicular to the director of the liquid crystal molecules ( ⁇ ) of 5.0 or more, more preferably of 6.0 or more, more preferably of 7.0 or more, more preferably of 8.0 or more, more preferably of 9 or more and, most preferably, of 10.0 or more.
• the liquid crystalline medium of the present invention has a dielectric anisotropy of 0.5 or more preferably of 1 .5 or more and a dielectric ratio ( ⁇ / ⁇ ) of 2.0 or less and comprises a) one or more compounds of formula B, preferably selected from the group of compounds of formulae B-1 and B-2, preferably in a concentration in the range from 1 % to 60 %, more preferably in the range from 5 % to 40 %, particularly preferably in the range from 8 % to 35 %,
• L 21 and L 22 denote H or F, preferably L 21 denotes F,
• H or F independently of one another, denote H or F, preferably L 31 denotes F, denotes halogen, halogenated alkyl or alkoxy having 1 to 3 C atoms or halogenated alkenyl or alkenyloxy having 2 or 3 C atoms, F, CI, -OCF 3 , -OCHF 2 ,
• R 41 and R 42 independently of one another, have the meaning indicated above for R 2 under formula II, preferably R 41 denotes alkyl and R 42 denotes alkyl or alkoxy or R 41 denotes alkenyl and R 42 denotes alkyl,
• R 51 and R 52 independently of one another, have one of the meanings given for R 41 and R 42 and preferably denote 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, alkoxyalkyi, alkenyl or alkenyloxy having 2 to 7 C atoms, preferably having 2 to 4 C atoms, preferably alkenyloxy,
• Z 51 to Z 53 each, independently of one another, denote -CH2-CH2-
• -CH2-O-, -CH CH-, -C ⁇ C-, -COO- or a single bond, preferably -CH2-CH2-, -CH2-O- or a single bond and particu- larly preferably a single bond, i and j each, independently of one another, denote 0 or 1 ,
• (i + j) preferably denotes 0, 1 or 2, more preferably 0 or 1 and, most preferably, 1 . again optionally, either alternatively or additionally, one or more dielectrically negative compounds selected from the group of formulae VI to IX:
• an unsubstituted alkyl radical having 1 to 7 C atoms preferably a straight-chain alkyl radical, more preferably an n-alkyl radical, most preferably propyl or pentyl
• an unsubstituted alkenyl radical having 2 to 7 C atoms preferably a straight-chain alkenyl radical, particularly preferably having 2 to 5 C atoms
• an unsubstituted alkoxy radical having 1 to 6 C atoms or an unsubstituted alkenyloxy radical having 2 to 6 C atoms denotes an unsubstituted alkyl radical having 1 to 7 C atoms, an unsubstituted alkoxy radical having 1 to 6 C atoms or an unsubstituted alkenyloxy radical having 2 to 6 C atoms
• denotes 0 or 1 denotes an unsubstituted alkyl radical having 1 to 7 C atoms, preferably a straight-chain alkyl radical, more preferably
• an unsubstituted alkyl radical having 1 to 7 C atoms preferably a straight-chain alkyl radical, more preferably an n-alkyl radical, most preferably propyl or pentyl, or an unsubstituted alkenyl radical having 2 to 7 C atoms, preferably a straight-chain alkenyl radical, particularly preferably having 2 to 5 C atoms, denotes an unsubstituted alkyl radical having 1 to 7 C atoms, preferably having 2 to 5 C atoms, an unsubstituted alkoxy radical having 1 to 6 C atoms, preferably having 1 ,
• R 91 and R 92 independently of one another have the meaning given for R 72 above,
• R 91 preferably denotes an alkyl radical having 2 to 5 C atoms, preferably having 3 to 5 C atoms,
• R 92 preferably denotes an alkyl or alkoxy radical having 2 to 5 C atoms, more preferably an alkoxy radical having 2 to 4 C atoms, or an alkenyloxy radical having 2 to 4 C atoms.
• p and q independently of each other denote 0 or 1
• alkyi denotes 0 or 1 , independently of each other denote alkyi, alkoxy, fluorinated alkyi or fluorinated alkoxy, preferably having 1 to 7 C atoms, alkenyl, alkenyloxy, alkoxyalkyl or
• alkenyl having 2 to 7 C atoms and preferably alkyi, alkoxy, alkenyl or alkenyloxy, most preferably alkyl, alkoxy or alkenyloxy, and R 11 alternatively
• R 1 and R 12 alternatively denotes X 1 ,
• R 1 denotes alkyl, alkoxy, fluorinated alkyl or fluorinated
• alkoxy preferably having 1 to 7 C atoms, alkenyl, alkenyloxy, alkoxyalkyl or fluorinated alkenyl, preferably having 2 to 7 C atoms and preferably alkyl or alkenyl, and
• X 1 denotes F, CI, fluorinated alkyl, fluorinated alkenyl,
• fluorinated alkoxy or fluorinated alkenyoxy the latter four groups preferably having 1 to 4 C atoms, more preferably F, CI, CF 3 or OCF 3 , from which the compounds of formula B are excluded.
• the liquid-crystalline media in accordance with the present application preferably have a nematic phase.
• R 1 alkyl means an alkyl group, which may be straight-chain or branched. Each of these radicals is preferably straight-chain and preferably has 1 , 2, 3, 4, 5, 6, 7 or 8 C atoms and is accordingly preferably methyl, ethyl, n-propyl, n- butyl, n-pentyl, n-hexyl or n-heptyl.
• Respective branched groups, especially for R 1 , which lead to chiral compounds are also called chiral groups in this application.
• Particularly preferred chiral groups are 2-alkyl, 2-alkoxy, 2-methylalkyl, 2-methylalkoxy, 2- fluoroalkyi, 2-fluoroalkoxy, 2-(2-ethin)-alkyl, 2-(2-ethin)-alkoxy, 1 ,1 ,1 -trifluoro-2- alkyl and 1 ,1 ,1 -trifluoro-2-alkoxy.
• the compounds of formula B are selected from the group of compounds of formulae B-1 and B-2:
• alkyl, alkoxy, fluorinated alkyl or fluorinated alkoxy preferably having 1 to 7 C atoms, alkenyl, alkenyloxy, alkoxyalkyi or fluorinated alkenyl having 2 to 7 C atoms and preferably alkyl or alkenyl
• the compounds of formula I are selected from the group of compounds of formulae 1-1 and I-2:
• alkyl, alkoxy, fluorinated alkyl or fluorinated alkoxy preferably having 1 to 7 C atoms, alkenyl, alkenyloxy, alkoxyalkyi or fluorinated alkenyl having 2 to 7 C atoms and preferably alkyl, alkoxy, alkenyl or alkenyloxy, most preferably alkoxy or alkenyloxy, denotes alkyl, alkoxy, fluorinated alkyl or fluorinated alkoxy, preferably having 1 to 7 C atoms, alkenyl, alkenyloxy, alkoxyalkyi or fluorinated alkenyl having 2 to 7 C atoms and preferably alkyl or alkenyl, and X 1 denotes F, CI, CN, NCS, fluohnated alkyl, fluorinated alkenyl, fluorinated alkoxy or fluorinated alkenlyoxy, the latter four groups preferably having 1 to 7 C atoms, al
• the stereomers of B-1 are separated by usual means, such as flash chromatography and or re-recystallization, either with or without use of seed crystals, which may be applied as single, sole steps or repeatedly and/or in combination with each other.
• the process and the subsequent work-up of the reaction mixture can basically be carried out as batch reaction or in a continuous reaction manner.
• the continuous reaction manner comprises, for example, the reaction in a continuous stirred-tank reactor, a stirred-reactor cascade, a loop or cross-flow reactor, a flow tube or in a micro-reactor.
• reaction mixtures are optionally worked up, as required, by filtration via solid phases, chromatography, separation between immiscible phases (for example extraction), adsorption on solid supports, distilling-off of solvents and/or azeotropic mixtures, selective distillation, sublimation, crystallization, co-crystallization or by nanofiltration on membranes.
• the compounds of formula I-2 are preferably prepared e.g. according to the following scheme.
• the invention furthermore relates to the use of liquid-crystal mixtures and liquid-crystalline media according to the invention in IPS and FFS displays, in particular the use in SG-FFS displays containing a liquid-crystalline medium, for improving the response times and/or the transmission.
• the invention furthermore relates to a liquid-crystal display containing a liquid-crystalline medium according to the invention, in particular an IPS or FFS display, particularly preferably a FFS or SG-FFS display.
• the invention furthermore relates to a liquid-crystal display of the IPS or FFS type comprising a liquid-crystal cell consisting of two substrates, where at least one substrate is transparent to light and at least one substrate has an electrode layer, and a layer, located between the substrates, of a liquid-crystalline medium comprising a polymerised component and a low-molecular-weight component, where the polymerised component is obtainable by polymerisation of one or more polymerisable compounds in the liquid-crystalline medium between the substrates of the liquid-crystal cell, preferably with application of an electrical voltage and where the low- molecular-weight component is a liquid-crystal mixture according to the invention as described above and below.
• the displays in accordance with the present invention are preferably addressed by an active matrix (active matrix LCDs, AMDs for short), preferably by a matrix of thin-film transistors (TFTs).
• active matrix LCDs active matrix LCDs, AMDs for short
• TFTs thin-film transistors
• the liquid crystals according to the invention can also be used in an advantageous manner in displays having other known addressing means.
• the invention furthermore relates to a process for the preparation of a liquid-crystalline medium according to the invention by mixing one or more compounds of formula B, preferably selected from the group of
• FFS FFFS
• mesogenic group is known to the person skilled in the art and is described in the literature, and denotes a group which, due to the ani- sotropy of its attracting and repelling interactions, essentially contributes to causing a liquid-crystalline (LC) phase in low-molecular-weight or polymeric substances.
• Compounds containing mesogenic groups do not necessarily have to have a liquid-crystalline phase themselves. It is also possible for mesogenic compounds to exhibit liquid- crystalline phase behaviour only after mixing with other compounds and/or after polymerisation. Typical mesogenic groups are, for example, rigid rod- or disc-shaped units.
• spacer group or "spacer” for short, also referred to as "Sp” above and below, is known to the person skilled in the art and is described in the literature, see, for example, Pure Appl. Chem. 73(5), 888 (2001 ) and C. Tschierske, G. Pelzl, S. Diele, Angew. Chem. 2004, 1 16, 6340-6368.
• spacer group or "spacer” for short, also referred to as "Sp” above and below, is known to the person skilled in the art and is described in the literature, see, for example, Pure Appl. Chem. 73(5), 888 (2001 ) and C. Tschierske, G. Pelzl, S. Diele, Angew. Chem. 2004, 1 16, 6340-6368.
• spacer group or “spacer” above and below denotes a flexible group which connects the mesogenic group and the polymerisable group(s) to one another in a polymerisable mesogenic compound.
• liquid-crystalline medium is intended to denote a medium which comprises a liquid-crystal mixture and one or more polymerisable compounds (such as, for example, reactive mesogens).
• liquid-crystal mixture (or “host mixture”) is intended to denote a liquid-crystalline mixture which consists exclusively of unpoly- merisable, low-molecular-weight compounds, preferably of two or more liquid-crystalline compounds and optionally further additives, such as, for example, chiral dopants or stabilisers.
• liquid-crystal mixtures and liquid-crystal- line media which have a nematic phase, in particular at room temperature.
• the liquid-crystal medium comprises one or more dielectrically positive compounds having a dielectric anisotropy of greater than 3, selected from the group of the com- pounds of the formulae 11-1 and II-2:
• n which the parameters have the respective meanings indicated above under formula II, and L 23 and L 24 , independently of one another, denote H or F, preferably L 23 denotes F, and
• X 2 preferably denotes F or OCF3, particularly preferably F, and, in the case of formula II-2,
• the media in accordance with the present invention may comprise, alternatively or in addition to the compounds of the formulae 111-1 and/or III-2, one or more compounds of the formula III-3
• the liquid-crystal medium preferably comprises compounds selected from the group of the compounds of the formulae 11-1 and II-2 in which L 21 and L 22 and/or L 23 and L 24 both denote F.
• the liquid-crystal medium comprises compounds selected from the group of the compounds of the formulae 11-1 and II-2 in which L 21 , L 22 , L 23 and L 24 all denote F.
• the liquid-crystal medium preferably comprises one or more compounds of the formula 11-1 .
• the compounds of the formula 11-1 are preferably selected from the group of the compounds of the formulae 11-1 a to 11-1 e, preferably one or more compounds of formulaell-1 a and/or 11-1 b and/or II- 1 d, preferably of formula 11-1 a and/or 11-1 d or 11-1 b and/or 11-1 d, most preferably of formula ll-1d:
• L 21 and L 22 both denote F and/or L 23 and L 24 both denote F, and in formula 11-1 e,
• L 21 , L 22 and L 23 denote F.
• the liquid-crystal medium preferably comprises one or more compounds of the formula II-2, which are preferably selected from the group of the compounds of the formulae ll-2a to ll-2k, preferably one or more compounds each of formulae ll-2a and/or ll-2h and/or ll-2j:
• the liquid-crystal medium preferably comprises compounds selected from the group of the compounds of the formulae ll-2a to ll-2k in which L 21 and L 22 both denote F and/or L 23 and L 24 both denote F.
• the liquid-crystal medium comprises compounds selected from the group of the compounds of the formulae ll-2a to ll-2k in which L 21 , L 22 , L 23 and L 24 all denote F.
• Especially preferred compounds of the formula II-2 are the compounds of the following formulae, particularly preferred of formulae ll-2a-1 and/or II- 2h-1 and/or ll-2k-2:
• the liquid-crystal medium preferably comprises one or more compounds of the formula 111-1 .
• the compounds of the formula 111-1 are preferably selected from the group of the compounds of the formulae lll-1 a to lll-1j, preferably from formulae lll-1 c, lll-1f, lll-1 g and lll-1j:
• the parameters L 33 and L 34 independently of one another and of the other parameters, denote H or F and the parameters L 35 and L 36 , independently of one another and of the other parameters, denote H or F.
• the liquid-crystal medium preferably comprises one or more compounds of the formula lll-1 c, which are preferably selected from the group of the compounds of the formulae lll-1 c-1 to lll-1 c-5, preferably of formulae III- 1 c-1 and/or lll-1 c-2, most preferably of formula 111 - 1 c- 1 :
• the liquid-crystal medium preferably comprises one or more compounds of the formula lll-1f, which are preferably selected from the group of the compounds of the formulae lll-1f-1 to lll-1f-6, preferably of formulae III-1M and/or lll-1f-2 and/or lll-1f-3 and /or IIMf-6, more preferably of formula lll-1f-3 and/or lll-1f-6, more preferably of formula lll-1f-6:
• the liquid-crystal medium preferably comprises one or more compounds of the formula lll-1g, which are preferably selected from the group of the compounds of the formulae lll-1 g-1 to lll-1g-5, preferably of formula lll-1 g-3:
• the liquid-crystal medium preferably comprises one or more compounds of the formula lll-1 h, which are preferably selected from the group of the compounds of the formulae lll-1 h-1 to lll-1 h-3, preferably of the formula lll-1 h-3:
• X 3 preferably denotes F.
• the liquid-crystal medium preferably comprises one or more compounds of the formula lll-1 i, which are preferably selected from the group of the compounds of the formulae lll-1 i-1 and lll-1 i-2, preferably of the formula ⁇ -1 i-2:
• the liquid-crystal medium preferably comprises one or more compounds of the formula lll-1j, which are preferably selected from the group of the compounds of the formulae lll-1j-1 and lll-1j-2, preferably of the formula lll-1j-1 :
• the liquid-crystal medium preferably comprises one or more compounds of the formula III-2.
• the compounds of the formula III-2 are preferably selected from the group of the compounds of the formulae lll-2a and lll-2b, preferably of formula lll-2b:
• the liquid-crystal medium preferably comprises one or more compounds of the formula lll-2a, which are preferably selected from the group of the compounds of the formulae lll-2a-1 to lll-2a-6:
• the liquid-crystal medium preferably comprises one or more compounds of the formula lll-2b, which are preferably selected from the group of the compounds of the formulae lll-2b-1 to lll-2b-4, preferably lll-2b-4:
• the media in accordance with the present invention may comprise one or more compounds of the formula III-3
• These compounds are preferably selected from the group of the formulae lll-3a and lll-3b:
• the liquid-crystalline media in accordance with the present invention preferably comprise one or more dielectrically neutral compounds having a dielectric anisotropy in the range from -1 .5 to 3, preferably selected from the group of the compounds of the formulae VI, VII, VIII and IX.
• the elements all include their respective isotopes.
• one or more H in the compounds may be replaced by D, and this is also particularly preferred in some embodiments.
• a correspondingly high degree of deuteration of the corresponding compounds enables, for example, detection and recognition of the compounds. This is very helpful in some cases, in particular in the case of the compounds of formula I.
• the media according to the invention in each case comprise one or more compounds of formula VI selected from the group of the compounds of the formulae VI-1 and VI- 2, preferably one or more compounds each of formulae VI-1 and one or more compounds of formula VI-2,
• R 61 and R 62 independently of each other denote methoxy, ethoxy, propoxy, butoxy (also or pentoxy, preferably ethoxy, butoxy or pentoxy, more preferably ethoxy or butoxy and, most preferably butoxy. in formula VI-2
• R 61 preferably denotes vinyl, 1 -E-propenyl, but-4-en-1 -yl, pent-
• R 62 denotes an unsubstituted alkyl radical having 1 to 7 C
• atoms preferably having 2 to 5 C atoms, or, preferably, an unsubstituted alkoxy radical having 1 to 6 C atoms, particularly preferably having 2 or 4 C atoms and, most preferably, ethoxy, and
• the media according to the invention in each case comprise one or more compounds of formula VII selected from the group of the compounds of the formulae VII-1 to VII- 3, preferably one or more compounds each of the formulae VII-1 and one or more compounds of formula VII-2,
• R 71 denotes vinyl, 1 -E-propenyl, but-4-en-1 -yl, pent-1 -en-1 -yl or pent-3-en-1 -yl, n-propyl or n-pentyl and
• R 72 denotes an unsubstituted alkyl radical having 1 to 7 C atoms, preferably having 2 to 5 C atoms, or, preferably, an unsubstituted alkoxy radical having 1 to 6 C atoms, particularly preferably having 2 or 4 C atoms and, most preferably, ethoxy.
• the media according to the invention in each case comprise one or more compounds of formula VI-1 selected from the group of the following compounds:
• the media according to the invention in each case comprise one or more compounds of formula VI-2 selected from the group of the following compounds:
• the media according to the invention in each case comprise one or more compounds of formula V II-1 selected from the group of the following compounds:
• the media according to the invention in each case comprise one or more compounds of formula VII-2 selected from the group of the following compounds:
• the media in accordance with the present invention preferably comprise one or more dielectrically negative compounds selected from the group of compounds of the formulae VI and VII preferably in a total concentration in the range from 5% or more to 90% or less, preferably from 10% or more to 80% or less, particularly preferably from 20% or more to 70% or less.
• the media according to the invention in each case comprise one or more compounds of formula VIII selected from the group of the compounds of the formulae VIII-1 to VIII-3, preferably one or more compounds each of the formulae VIII-1 and/or one or more compounds of formula VIII-3,
• R 81 denotes vinyl, 1 -E-propenyl, but-4-en-1 -yl, pent-1 -en-1 -yl or pent-3-en-1 -yl, ethyl, n-propyl or n-pentyl, alkyl, preferably ethyl, n-propyl or n-pentyl and
• R 82 denotes an unsubstituted alkyl radical having 1 to 7 C atoms, preferably having 1 to 5 C atoms or an
• R 82 denotes preferably akioxy having 2 or 4 C atoms and, most preferably, ethoxy and in formula VIII-3 it denotes preferably alky, preferably methyl, ethyl or n-propyl, most preferably methyl.
• the medium comprises one or more compounds of formula IV, preferably of formula IVa in which
• R 41 denotes an unsubstituted alkyl radical having 1 to 7 C atoms or an unsubstituted alkenyl radical having 2 to 7 C atoms, preferably an n-alkyl radical, particularly preferably having 2, 3, 4 or 5 C atoms, and denotes an unsubstituted alkyl radical having 1 to 7 C atoms, an unsubstituted alkenyl radical having 2 to 7 C atoms, or an unsubstituted alkoxy radical having 1 to 6 C atoms, both preferably having 2 to 5 C atoms, an unsubstituted alkenyl radical preferably having 2, 3 or 4 C atoms, more preferably a vinyl radical or 1 -propenyl radical and in particular a vinyl radical.
• the medium comprises one or more compounds of formula IV selected from the group of the compounds of the formulae IV-1 to IV-4, preferably of formula IV-1 ,
• the media according to the invention comprise one or more compounds of formula IV-1 and/or one or more compounds of formula IV-2.
• the medium comprises one or more compounds of formula V.
• the media according to the invention preferably comprise the following compounds in the total concentrations indicated:
• the media in accordance with the present invention in addition to the compounds of formula B or the preferred sub-formulae thereof, and to the compounds of formulae VI and/or VII and/or VIII and/or IX and/or I preferably comprise one or more dielectrically neutral compounds selected from the group of compounds of formulae IV and V preferably in a total concentration in the range from 5 % or more to 90 % or less, preferably from 10 % or more to 80 % or less, particularly preferably from 20 % or more to 70 % or less.
• the medium according to the invention in a particularly preferred embodiment comprises one or more compounds of formula B in a total concentration in the range from 3 % or more to 50 % or less, preferably in the range from 5 % or more to 30 % or less, and one or more compounds of formula I in a total concentration in the range from 3 % or more to 50 % or less, preferably in the range from 5 % or more to 30 % or less, and/or one or more compounds of formula II in a total concentration in the range from 5 % or more to 50 % or less, preferably in the range from 10 % or more to 40 % or less, and/or one or more compounds of formula VII-1 in a total concentration in the range from 5 % or more to 30 % or less, and/or one or more compounds of formula VII-2 in a total concentration in the range from 3 % or more to 30 % or less.
• the concentration of the compounds of formula B in the media according to the invention is in the range from 1 % or more to 60 % or less, more preferably from 5 % or more to 40 % or less, most preferably from 8 % or more to 35 % or less.
• the concentration of the compounds of formula I in the media according to the invention is in the range from 1 % or more to 60 % or less, more preferably from 5 % or more to 40 % or less, most preferably from 8 % or more to 35 % or less
• the concentration of the compounds of formula II in the media is in the range from 3 % or more to 60 % or less, more preferably from 5 % or more to 55 % or less, more preferably from 10 % or more to 50 % or less and, most preferably, from 15 % or more to 45 % or less.
• the concentration of the compounds of formula VII in the media is in the range from 2 % or more to 50 % or less, more preferably from 5 % or more to 40 % or less, more preferably from 10 % or more to 35 % or less and, most preferably, from 15 % or more to 30 % or less.
• the concentration of the compounds of formula VII-1 in the media is in the range from 1 % or more to 40 % or less, more preferably either from 2 % or more to 35 % or less, or, alternatively, from 15 % or more to 25 % or less.
• the concentration of the compounds of formula VII-2 in the media is in the range from 1 % or more to 40 % or less, more preferably from 5 % or more to 35 % or less and, most preferably, from 10 % or more to 30 % or less.
• the present invention also relates to electro-optical displays or electro- optical components which contain liquid-crystalline media according to the invention. Preference is given to electro-optical displays which are based on the VA, ECB, IPS or FFS effect, preferably on the VA, IPS or FFS effect, and in particular those which are addressed by means of an active- matrix addressing device.
• the present invention likewise relates to the use of a liquid- crystalline medium according to the invention in an electro-optical display or in an electro-optical component, and to a process for the preparation of the liquid-crystalline media according to the invention, characterised in that one or more compounds of formula B are mixed with one or more compounds of formula I, preferably with one or more compounds of the sub- formulae 1-1 and/or I-2, preferably of formula I-2 and/or one or more com- pounds of formula II, preferably with one or more compounds of the sub- formulae 11-1 and/or II-2 with one or more compounds of formula VII, preferably with one or more compounds of the sub-formulae VII-1 and/or VII-2, particularly preferably one or more compounds from two or more, preferably from three or more, different formulae thereof and very particularly preferably from all four of these formulae 11-1 , II-2, VII-1 and VII-2 and one or more further compounds, preferably selected from the group of the compounds of the formulae IV and V, more preferably with one or more compounds both
• alkyl and alkyi independently of one another, denote alkyl having 1 to 7 C atoms, preferably having 2 to 5 C atoms, alkoxy denotes alkoxy having 1 to 5 C atoms, preferably having 2 to 4 C atoms.
• the medium comprises one or more compounds of formula V selected from the group of the compounds of the formulae V-1 and V-2, preferably of formulae V-1 ,
• R 51 denotes alkyl having 1 to 7 C atoms or alkenyl having 2 to
• R 52 denotes alkyl having 1 to 7 C atoms, alkenyl having 2 to 7
• the medium comprises one or more compounds of formula V-1 selected from the group of the compounds of the formulae V-1 a and V-1 b,
• alkyl and alkyl' independently of one another, denote alkyl having 1 to 7 C atoms, preferably having 2 to 5 C atoms, and alkenyl denotes alkenyl having 2 to 7 C atoms, preferably having
• the present invention relates to a method for the reduction of the wavelength dispersion of the birefringence of a liquid-crystalline medium which comprises one or more compounds of formula II, optionally one or more compounds selected from the group of the compounds of the formulae VII-1 and VII-2 and/or one or more compounds of formula IV and/or one or more compounds of formula V, characterised in that one or more compounds of formula B are used in the medium.
• the media according to the invention may optionally also comprise a di- electrically positive component, whose total concentration is preferably 20 % or less, more preferably 10 % or less, based on the entire medium.
• liquid-crystal media according to the invention comprise in total, based on the mixture as a whole,
• the liquid-crystal media in accordance with the present invention may comprise one or more chiral compounds. Particularly preferred embodiments of the present invention meet one or more of the following conditions, where the acronyms (abbreviations) are explained in Tables A to C and illustrated by examples in Table D.
• the media according to the present invention fulfil one or more of the following conditions.
• the liquid-crystalline medium has a birefringence of 0.060 or more, particularly preferably 0.070 or more.
• the liquid-crystalline medium has a birefringence of 0.200 or less, particularly preferably 0.180 or less.
• the liquid-crystalline medium has a birefringence in the range from 0.090 or more to 0.160 or less.
• the liquid-crystalline medium comprises one or more particularly preferred compounds of formula Bl, preferably selected from the (sub-) formulae B-1 and B-2, most preferably of (sub-)formula B-2.
• the liquid-crystalline medium comprises one or more particularly preferred compounds of formula I, preferably selected from the (sub-) formulae 1-1 and I-2, most preferably of (sub-)formula I-2.
• the total concentration of the compounds of formula II in the mixture as a whole is 25 % or more, preferably 30 % or more, and is preferably in the range from 25 % or more to 49 % or less, particularly preferably in the range from 29 % or more to 47 % or less, and very particularly preferably in the range from 37 % or more to 44 % or less.
• the liquid-crystalline medium comprises one or more compounds of formula IV selected from the group of the compounds of the following formulae: CC-n-V and/or CC-n-Vm and/or CC-V-V and/or CC-V-Vn and/or CC-nV-Vn, particularly preferably CC-3-V, preferably in a concentration of up to 60 % or less, particularly preferably up to 50 % or less, and optionally additionally CC-3-V1 , preferably in a
• the media comprise the compound of formula CC-n-V, preferably CC-3-V, preferably in a concentration of 1 % or more to 60 % or less, more preferably in a concentration of 3 % or more to 35 % or less.
• the total concentration of the compounds of formula CC-3-V in the mixture as a whole preferably either is 15 % or less, preferably 10 % or less or 20 % or more, preferably 25 % or more.
• the total concentration of the compounds of formula Y-nO-Om in the mixture as a whole is 2 % or more to 30 % or less, preferably 5 % or more to 15 % or less.
• the total concentration of the compounds of formula CY-n-Om in the mixture as a whole is 5 % or more to 60 % or less, preferably 15% or more to 45 % or less.
• the total concentration of the compounds of formula CCY-n-Om and/ or CCY-n-m, preferably of CCY-n-Om, in the mixture as a whole is 5 % or more to 40 % or less, preferably 1 % or more to 25 % or less.
• the total concentration of the compounds of formula CLY-n-Om in the mixture as a whole is 5 % or more to 40 % or less, preferably 10 % or more to 30 % or less.
• the liquid-crystalline medium comprises one or more compounds of formula IV, preferably of the formulae IV-1 and/or IV-2, preferably in a total concentration of 1 % or more, in particular 2 % or more, and very particularly preferably 3 % or more to 50 % or less, preferably
• the liquid-crystalline medium comprises one or more compounds of formula V, preferably of the formulae V-1 and/or V-2, preferably in a total concentration of 1 % or more, in particular 2 % or more, and very particularly preferably 15 % or more to 35 %or less, preferably to 30 % or less.
• the total concentration of the compounds of formula CCP-V2-n, preferably CCP-V2-1 , in the mixture as a whole preferably is 1 % or more to 15 % or less, preferably 2 % or more to 10 % or less.
• the invention furthermore relates to an electro-optical display having active-matrix addressing based on the VA, ECB, IPS, FFS or UB-FFS effect, characterised in that it contains, as dielectric, a liquid-crystalline medium in accordance with the present invention.
• the liquid-crystal mixture preferably has a nematic phase range having a width of at least 70 degrees.
• the rotational viscosity ⁇ 1 is preferably 350 mPa s or less, preferably 250 mPa s or less and, in particular, 150 mPa s or less.
• the mixtures according to the invention are suitable for all IPS and FFS- TFT applications using dielectrically positive liquid crystalline media, such as, e.g. SG-FFS.
• liquid-crystalline media according to the invention preferably virtually completely consist of 4 to 15, in particular 5 to 12, and particularly
• the liquid-crystalline media according to the invention may optionally also comprise more than 18 compounds. In this case, they preferably comprise 18 to 25 compounds. In a preferred embodiment, the liquid-crystal media according to the invention predominantly comprise, preferably essentially consist of and, most preferably, virtually completely consist of compounds, which do not comprise a cyano group. In a preferred embodiment, the liquid-crystal media according to the invention comprise compounds selected from the group of the compounds of the formulae I, II, and II, IV and V and VI to IX, preferably selected from the group of the compounds of the formulae 1-1 , I-2, 11-1 , II-2, 111-1 , III-2, IV, V, VII-1 , VII-2, VIII and IX; they preferably consist predominantly,
• the liquid-crystal media according to the invention preferably have a nematic phase from in each case at least -10°C or less to 70°C or more, particularly preferably from -20°C or less to 80°C or more, very particularly preferably from -30°C or less to 85°C or more and most preferably from -40°C or less to 90°C or more.
• the expression "have a nematic phase” here means on the one hand that no smectic phase and no crystallisation are observed at low temperatures at the corresponding temperature and on the other hand that no clearing occurs on heating out of the nematic phase.
• the investigation at low temperatures is carried out in a flow viscometer at the corresponding temperature and checked by storage in test cells having a cell thickness corresponding to the electro-optical application for at least 100 hours. If the storage stability at a temperature of -20°C in a corresponding test cell is 1000 h or more, the medium is regarded as stable at this temperature. At temperatures of -30°C and -40°C, the corresponding times are 500 h and 250 h respectively. At high temperatures, the clearing point is measured in capillaries by conventional methods.
• the liquid-crystal media according to the invention are characterised by optical anisotropy values in the moderate to low range.
• the birefringence values are preferably in the range from 0.075 or more to 0.130 or less, particularly preferably in the range from 0.085 or more to 0.120 or less and very particularly preferably in the range from 0.090 or more to 0.1 15 or less.
• the liquid-crystal media according to the invention have a positive dielectric anisotropy and relatively high absolute values of the dielectric anisotropy ⁇ , which preferably is in the range from 2.0 or more to 20 or less, more preferably to 15 or less, more preferably from 3.0 or more to 10 or less, particularly preferably from 4.0 or more to 9.0 or less and very particularly preferably from 4.5 or more to 8.0 or less.
• the liquid-crystal media according to the invention preferably have relatively low values for the threshold voltage (Vo) in the range from 1 .0 V or more to 5.0 V or less, preferably to 2.5 V or less, preferably from 1 .2 V or more to 2.2 V or less, particularly preferably from 1 .3 V or more to 2.0 V or less.
• Vo threshold voltage
• the liquid-crystal media according to the invention preferably have relatively high values of the average dielectric constant ( ⁇ av . ⁇ ( ⁇
• + 2 ⁇ )/3 are preferably in the range from 8.0 or more to 25.0 or less, preferably from 8.5 or more to 20.0 or less, still more preferably from 9.0 or more to 19.0 or less, particularly preferably from 10.0 or more to 18.0 or less and very particularly
• liquid-crystal media according to the invention have high values for the VHR in liquid-crystal cells.
• the values of the VHR of these media are greater than or equal to 95 %, preferably greater than or equal to 97%, particularly preferably greater than or equal to 98 % and very particularly preferably greater than or equal to 99 %, and after 5 minutes in the oven at 100°C in the cells, these are greater than or equal to 90 %, preferably greater than or equal to 93 %, particularly preferably greater than or equal to 96 % and very particularly preferably greater than or equal to 98 %.
• liquid-crystal media having a low addressing voltage or threshold voltage here have a lower VHR than those having a higher addressing voltage or threshold voltage, and vice versa.
• the term "compounds”, also written as "com- pound(s)" means both one and also a plurality of compounds, unless explicitly indicated otherwise.
• the liquid-crystalline media according to the invention comprise one or more compounds of formula B, preferably selected from the group of formulae CB-n-F, CB-n-OT, CB-n-T, LB-n-F, LB-n-OT and LB-n-T, more preferably selected from the group of formulae CB-n-OT, CB-n-T, LB-n-OT and LB-n-T, preferably selected from the group of formulae CB-n-OT, CB- n-T, and one or more compounds of formula I, preferably selected from the group of the formulae B-nO-Om, B(S)-nO-Om, B-nO-OT, B-nO-T, B-n-OT and B-n- F, more preferably selected from the group of formulae B-
• the media according to the invention comprise one or more compounds of formula IX selected from one or more formulae of the group of the compounds of the formulae IX-1 to IX-4, very particularly preferably of the formulae IX-1 to IX-3,
• the medium comprises one or more compounds of formula IX-3, preferably of formula IX-3-a,
• alkyl and alkyl' independently of one another, denote alkyl having 1 to 7 C atoms, preferably having 2 to 5 C atoms.
• the compounds of formula IX are used in the liquid crystalline media according to the present application, they are preferably present in a concentration of 20 % or less, more preferably of 10 % or less and, most preferably, of 5 % or less and for the individual i.e. (homologous) compounds preferably in a concentration of 10 % or less and, more preferably, of 5 % or less.
• the concentration of the constituents in question in the composition is preferably 5% or more, particularly preferably 10% or more, very particularly preferably 20% or more,
• the concentration of the constituents in question in the composition is preferably 50% or more, particularly preferably 55% or more and very particularly preferably 60% or more,
• composition preferably 80% or more, particularly preferably 90% or more and very particularly preferably 95% or more, and
• the concentration of the constituents in question in the composition is preferably 98% or more, particularly preferably 99% or more and very particularly preferably 100.0%.
• the concentration of the compound in question is preferably 1 % or more, particularly preferably 2% or more, very particularly preferably 4% or more.
• ⁇ means less than or equal to, preferably less than, and ">” means greater than or equal to, preferably greater than.
• trans-1,4-cyclohexylene denotes a mixture of both cis- and trans-1 , 4-cyclohexylene, and denote 1 ,4-phenylene.
• dielectrically positive compounds means compounds having a ⁇ of > 1 .5
• dielectrically neutral compounds means those where -1 .5 ⁇ ⁇ 1 .5
• dielectrically negative compounds means those where
• the dielectric anisotropy of the compounds is determined here by dissolving 10% of the compounds in a liquid-crystalline host and determining the capacitance of the resultant mixture in each case in at least one test cell having a cell thickness of 20 ⁇ with homeotropic and with homogeneous surface alignment at 1 kHz.
• the measurement voltage is typically 0.5 V to 1 .0 V, but is always lower than the capacitive threshold of the respective liquid-crystal mixture investigated.
• the host mixture used for dielectrically positive and dielectrically neutral compounds is ZLI-4792 and that used for dielectrically negative compounds is ZLI-2857, both from Merck KGaA, Germany.
• the values for the respective compounds to be investigated are obtained from the change in the dielectric constant of the host mixture after addition of the compound to be investigated and extrapolation to 100% of the compound employed.
• the compound to be investigated is dissolved in the host mixture in an amount of 10%. If the solubility of the substance is too low for this purpose, the concentration is halved in steps until the investigation can be carried out at the desired temperature.
• the liquid-crystal media according to the invention may, if necessary, also comprise further additives, such as, for example, stabilisers and/or pleo- chroitic, e.g. dichroitic, dyes and/or chiral dopants in the usual amounts.
• the amount of these additives employed is preferably in total 0 % or more to 10 % or less, based on the amount of the entire mixture, particularly preferably 0.1 % or more to 6 % or less.
• the concentration of the individual compounds employed is preferably 0.1 % or more to 3 % or less. The concentration of these and similar additives is generally not taken into account when specifying the concentrations and concentration ranges of the liquid-crystal compounds in the liquid-crystal media.
• the liquid-crystal media according to the invention comprise a polymer precursor which comprises one or more reactive compounds, preferably reactive mesogens, and, if necessary, also further additives, such as, for example, polymerisation initiators and/or polymerisation moderators, in the usual amounts.
• the amount of these additives employed is in total 0 % or more to 10 % or less, based on the amount of the entire mixture, preferably 0.1 % or more to 2 % or less.
• concentration of these and similar additives is not taken into account when specify- ing the concentrations and concentration ranges of the liquid-crystal compounds in the liquid-crystal media.
• compositions consist of a plurality of compounds, preferably 3 or more to 30 or fewer, particularly preferably 6 or more to 20 or fewer and very particularly preferably 10 or more to 16 or fewer compounds, which are mixed in a conventional manner.
• the desired amount of the components used in lesser amount is dissolved in the components making up the principal constituent of the mixture. This is advantageously carried out at elevated temperature. If the selected temperature is above the clearing point of the principal constituent, completion of the dissolution operation is particularly easy to observe.
• the mixtures according to the invention exhibit very broad nematic phase ranges having clearing points of 65°C or more, very favourable values for the capacitive threshold, relatively high values for the holding ratio and at the same time very good low-temperature stabilities at -30°C and -40°C. Furthermore, the mixtures according to the invention are distinguished by low rotational viscosities ⁇ .
• the media according to the invention for use in VA, IPS, FFS or PALC displays may also comprise compounds in which, for example, H, N, O, CI, F have been replaced by the corresponding isotopes.
• the structure of the liquid-crystal displays according to the invention corresponds to the usual geometry, as described, for example, in
• liquid-crystal phases according to the invention can be modified by means of suitable additives in such a way that they can be employed in any type of, for example, IPS and FFS LCD display that has been disclosed to date.
• Table E below indicates possible dopants which can be added to the mixtures according to the invention. If the mixtures comprise one or more dopants, it is (they are) employed in amounts of 0.01 % to 4 %, preferably 0.1 % to 1 .0 %.
• Stabilisers which can be added, for example, to the mixtures according to the invention, preferably in amounts of 0.01 % to 6 %, in particular 0.1 % to 3 %, are shown below in Table F.
• threshold voltage relates to the capa- citive threshold (Vo), also known as the Freedericks threshold, unless explicitly indicated otherwise.
• the measurement cells have soda- lime glass substrates and are constructed in an ECB or VA configuration with polyimide alignment layers (SE-121 1 with diluent ** 26 (mixing ratio 1 :1 ), both from Nissan Chemicals, Japan), which have been rubbed perpendicularly to one another and effect homeotropic alignment of the liquid crystals.
• the surface area of the transparent, virtually square ITO electrodes is 1 cm 2 .
• a chiral dopant is not added to the liquid- crystal mixtures used, but the latter are also particularly suitable for applications in which doping of this type is necessary.
• the rotational viscosity is determined using the rotating permanent magnet method and the flow viscosity in a modified Ubbelohde
• the dispersion of the materials may for practical purposes be conveniently characterized in the following way, which is used throughout this
• birefringence are determined at a temperature of 20°C at several fixed wavelengths using a modified Abbe refractometer with homeotropically aligning surfaces on the sides of the prisms in contact with the material.
• the birefringence values are determined at the specific wavelength values of 436 nm (respective selected spectral line of a low pressure mercury lamp), 589 nm (sodium "D" line) and 633 nm (wavelength of a HE-Ne laser (used in combination with an attenuator/diffusor in order to prevent damage to the eyes of the observers.
• ⁇ ( ⁇ ) optical anisotropy measured at 20°C and wavelength ⁇ , ⁇ ( ⁇ ) change in optical anisotropy defined as:
• Table A shows the codes for the ring elements of the nuclei of the compound
• Table B lists the bridging units
• Table C lists the meanings of the symbols for the left- and right-hand end groups of the molecules.
• the acronyms are composed of the codes for the ring elements with optional linking groups, followed by a first hyphen and the codes for the left-hand end group, and a second hyphen and the codes for the right-hand end group.
• Table D shows illustrative structures of compounds together with their respective abbreviations.
• the mixtures according to the invention preferably comprise one or more compounds of the compounds mentioned below.
• n, m, k and I are, independently of one another, each an integer, preferably 1 to 9 preferably 1 to 7, k and I possibly may be also 0 and preferably are 0 to 4, more preferably 0 or 2 and most preferably 2, n preferably is 1 , 2, 3, 4 or 5, in the combination "-nO-" it preferably is 1 , 2, 3 or 4, preferably 2 or 4, m preferably is 1 , 2, 3, 4 or 5, in the combination "- Om” it preferably is 1 , 2, 3 or 4, more preferably 2 or 4.
• the combination "- IVm” preferably is "2V1 ".)
• Table E shows chiral dopants which are preferably employed in the mixtures according to the invention.
• the media according to the invention comprise one or more compounds selected from the group of the compounds from Table E.
• Table F shows stabilisers which can preferably be employed in the mixtures according to the invention in addition to the compounds of formula B.
• the parameter n here denotes an integer in the range from 1 to 12.
• the phenol derivatives shown can be employed as additional stabilisers since they act as antioxidants.
• the media according to the invention comprise one or more compounds selected from the group of the compounds from Table F, in particular one or more compounds selected from the group of the compounds of the following two formulae
• Exemplary compounds of formula B (having a high dielectric constant perpendicular to the director (s ⁇ ))are synthesized.
• Step 1 .1 3,2',3'-Trifluoro-4-trifluoromethoxy-biphenyl-2-ol
• room temperature and ambient temperature are used synonymously and signify a temperature of about 20°C, typically (20 ⁇ 1 )°C.
• the aqueous phase is separated and extracted with MTB ether.
• the combined organic phases are washed with distilled water and brine, dried (sodium sulphate) and concentrated in vacuo.
• the residue is purified by silica gel
• Step 1 .2 4,6-Difluoro-3-trifluoromethoxy-dibenzofuran
• Step 1 .3 1 -(4,6-Difluoro-7-trifluoromethoxy-dibenzofuran-3-yl)-4-propyl- cyclohexanol
• n-Butyllithium (27 mL, 15% in hexane, 43 mmol) is added to a solution of 4,6-difluoro-3-trifluoromethoxy-dibenzofuran (4) (10.3 g, 34 mmol) in THF (100 mL) at -70°C under nitrogen atmosphere.
• a solution of 4- propylcyclohexanone (6.0 g, 43 mmol) in THF (100 mL) is added after 1 h, and the reaction mixture is stirred for 2 h at -70°C. Then it is allowed to warm to room temperature and is stirred for additional 72 h.
• reaction is quenched with distilled water and hydrochloric acid (2 N) at 0°C and diluted with MTB ether.
• aqueous phase is separated and extracted with MTB ether.
• the combined organic phases are washed with distilled water and brine, dried (sodium sulphate) and concentrated in vacuo.
• the residue is purified by silica gel chromatography (solvent 1 -chlorobutane) to give 1 -(4,6-difluoro-7-trifluoromethoxy-dibenzofuran-3-yl)-4-propyl- cyclohexanol (5) as yellow crystals.
• Step 1 .4 4,6-Difluoro-3-(4-propyl-cyclohex-1 -enyl)-7-trifluoromethoxy- dibenzofuran
• Step 2.1 4,6-Difluoro-3-(4-propyl-cyclohexyl)-7-trifluoromethoxy- dibenzofuran
• B-2-B 4,6-Difluoro-3-(4-propyl-cyclohex-1 -enyl)-7-trifluoromethyl-dibenzofuran
• B-2-A 4,6-Difluoro-3-(4-propyl-cyclohex-1 - enyl)-7-trifluoronnethoxy-dibenzofuran (B-2-A), starting from 6-bromo-2- fluoro-3-trifluoromethylphenol and 2,3-difluoro-4-phenylboronic acid (1 ).
• Exemplary compounds having a high dielectric constant perpendicular to the director ( ⁇ ) and a high average dielectric constant (s av .) are provided.
• Compound examples B1 .1 to B1 .3 Compounds of formula B-1 are e.g.
• This compound (CB-3-OT) has a glass transition temperature (T g ) of -49°C, a melting point of 69°C, an extrapolated clearing point (5 % in ZLI- 4792 ) of 102°C, a phase sequence of T g -49°C K 69°C S A 86°C N 98 C I, a ⁇ of 1 .7 and an ⁇ of 10.5.
• This compound (LB-3-OT) has a melting point of 62°C, an extrapolated clearing point (5 % in ZLI-4792) of 97°C, a phase sequence of K 62°C S A 121 °C I, a ⁇ of 2.5 and an ⁇ of 10.5.
• This compound (LB-3-T) has a melting point of 89°C, a phase sequence of K 89°C S A 108°C I, an extrapolated clearing point (10 % in ZLI-4792) of 83°C, a ⁇ of 3.5 and an ⁇ of 12.5.
• This compound (B-2O-O5) has a melting point of 57°C, a ⁇ of -13.7 and an ⁇ av. of even 17.9.
• This compound (B-4O-O5) has similar preferably properties.
• This compound (B-5O-OT) has a melting point of 68°C, a ⁇ of only -3.7 and an ⁇ av. of even 18.6.
• This compound (B-6O-OT) has a melting point of 72°C.
• This compound (B-4-4) has a melting point of 38°C.
• This compound (B-5-2V) has a melting point of 35°C.
• This compound (B-V2-2V) has a melting point of 60°C
• This compound (B-2-O2) has a melting point of 60°C.
• This compound (B-3-O3) has a melting point of 54°C.
• This compound (B-3-O2V) has a melting point of 50°C.
• This compound (B-3-F) has a melting point of 76°C.
• This compound (B-5-F) has a melting point of 42°C.
• This compound (B-5-T) has a melting point of 46°C.
• This compound (B-5-OT) has a melting point of 46°C.
• This compound (B-2O-F) has a melting point of 1 14°C.
• This compound (B-5O-F) has a melting point of 65°C.
• This compound (B-5O-CI) has a melting point of 51 °C.
• This compound (B-4O-T) has a melting point of 81 °C
• This compound (B-5O-T) has a melting point of 74°C.
• This compound (B-6O-T) has a melting point of 76°C.
• This compound (B-V2O-OT) has a melting point of 87°C.
• This compound (CB-3-O4) has a phase range of K 76°C N 145.6°C I.
• This compound (PB-3-O4) has a phase range of K 122°C N (121 .6°C) I.
• This compound (GB-4-O2) has a phase range of K 69°C N (34.5°C) I.
• mixtures A-1 to A-6 have good dielectric ratios ( ⁇ / ⁇ ), good ratios of ( ⁇ /kn) and are characterized by very good transmissions in an FFS display and show very short response time. Moreover, they show excellent deep temperature stability at least up to a temperature of -20°C. Table 1 (continued)
• mixtures B-1 to B-6 have good dielectric ratios ( ⁇ / ⁇ ), good ratios of ( ⁇ /kn) and are characterized by very good transmissions in an FFS display and show very short response time. Moreover, they show excellent deep temperature stability at least up to a temperature of -20°C. Comparative Example C
• This mixture, mixture M-3 has a dielectric ratio ( ⁇ / ⁇ ) of 0.87, a ratio of (y 1 /k 11 ) of 4.28 mPa s / pN and is characterized by a very good transmission in an FFS display, shows a very short response time, and has a very good low temperature stability.
• Example 4
• This mixture, mixture M-4 has a dielectric ratio ( ⁇ / ⁇ ) of 1 .02, a ratio of (yi/kn) of 4.48 mPa s / pN and is characterized by a very good transmission in an FFS display, shows a very short response time, and has a very good low temperature stability.
• Example 5
• This mixture, mixture M-5 has a dielectric ratio ( ⁇ / ⁇ ) of 0.73, a ratio of (yi/kn) of 4.44 mPa s / pN and is characterized by a very good transmission in an FFS display, shows a very short response time, and has a very good low temperature stability.
• Example 6
• This mixture, mixture M-7 has a dielectric ratio ( ⁇ / ⁇ ) of 0.80, a ratio of (yi/kn) of 4.32 mPa s / pN and is characterized by a very good transmission in an FFS display, shows a very short response time, and has a very good low temperature stability.
• Example 8
• This mixture, mixture M-10 has a dielectric ratio ( ⁇ / ⁇ ) of 0.86, a ratio of (yi/kn) of 4.1 1 mPa s / pN and is characterized by a very good
• This mixture, mixture M-1 1 has a dielectric ratio ( ⁇ / ⁇ ) of 0.77, a ratio of (yi/kn) of 4.17 mPa-s / pN and is characterized by a very good
• This mixture, mixture M-12 has a dielectric ratio ( ⁇ / ⁇ ) of 1 .26, a ratio of (yi/kn) of 4.97 mPa-s / pN and is characterized by a very good
• This mixture, mixture M-13 has a dielectric ratio ( ⁇ / ⁇ ) of 1 .09, a ratio of (yi/kn) of 5.0 mPa s / pN and is characterized by a very good transmission in an FFS display, shows a very short response time, and has a very good low temperature stability.
• Example 14
• This mixture, mixture M-16 has a good dielectric ratio ( ⁇ / ⁇ ), a good ratio of (yi/kn) and is characterized by a very good transmission in an FFS display, shows a very short response time, and has a very good low temperature stability.
• ⁇ / ⁇ dielectric ratio
• yi/kn good ratio of (yi/kn)
• This mixture, mixture M-15 has a dielectric ratio ( ⁇ / ⁇ ) of 0.89, a ratio of (yi/kn) of 4.31 mPa s / pN and is characterized by a very good
• This mixture, mixture M-16 has has a dielectric ratio ( ⁇ / ⁇ ) of 0.93, a ratio of (yi/kn) of 4.36 mPa s / pN and is characterized by a very good transmission in an FFS display, shows a very short response time, and has a very good low temperature stability.
• Example 17
• This mixture, mixture M-28, is characterized by a very good transm in an FFS display and has a good low temperature stability.
• This mixture, mixture M-29, is characterized by a very good transm in an FFS display and has a good low temperature stability.
• This mixture, mixture M-33, is characterized by a very good transm in an FFS display and has a good low temperature stability.
• Example 34 The following mixture (M-34) is prepared and investigated.
• This mixture, mixture M-49, is characterized by a very good transm in an FFS display and has a good low temperature stability.
• This mixture, mixture M-64, is characterized by a very good transm in an FFS display and has a good low temperature stability.
• This mixture, mixture M-77, is characterized by a very good transm in an FFS display and has a good low temperature stability.
• This mixture, mixture M-81 is characterized by a very good transm in an FFS display and has a good low temperature stability.
• This mixture, mixture M-86 is characterized by a very good transm in an FFS display and has a good low temperature stability.

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