| 摘要 |
#CMT# #/CMT# Liquid crystal medium comprises difluorobenzene derivatives (I). #CMT# : #/CMT# Liquid crystal medium comprises difluorobenzene derivatives of formula (I). R 0>-A1-A2-A3-A4-X 0> (I) A1 : trans-1,4-cyclohexylene; A2 : 1,4-phenylene; A3 : 3-fluoro-1,4-phenylene; A4 : 3,5-difluoro-1,4-phenylene; R 0> : 1-15C alkyl or alkoxy, optionally halogenated and optionally with CH 2 groups replaced by ethynylene, CF 2O, CH=CH, 1,3-cyclobutylene, 2,5-spiro[3.3]heptylene, O, COO or OCO; X 0> : F, Cl, CN, SF 5, SCN, NCS or 1-6C haloalkyl, haloalkenyl, haloalkoxy or haloalkenyloxy. #CMT#USE : #/CMT# The liquid crystal medium is useful for electroptic purposes (claimed), especially in liquid crystal displays. #CMT#ADVANTAGE : #/CMT# The liquid crystal medium has a rapid switching time, low rotational viscosity, high birefringence, high clearing point, high dielectric anisotropy and low threshold voltage. #CMT#ORGANIC CHEMISTRY : #/CMT# Preferred Medium: This comprises 1-25 wt.% (I), 25-80 wt.% alkenyl derivatives of formula (II) and/or (III) and 5-40 wt.% terphenyl derivatives of formula (XII). R 3>-A1-A-(A2) a-R 0> (II) R 3>-A2-A2-R 0> (III) R 1>-A2-A'-A2-R 2> (XII) A : A1 or A2; A' : A2 or A3; a : 0 or 1; R 1>, R 2> : 1-9C n-alkyl, alkoxy, oxaalkyl, fluoroalkyl or alkenyl; R 3> : 2-9C alkenyl. |
