Liquid-crystal compounds having large negative value of permittivity anisotropy, liquid-crystal composition, and liquid-crystal display element
申请人:Chisso Corporation
公开号:US06348244B1
公开(公告)日:2002-02-19
An object of the present invention is to provide novel liquid crystalline compounds having a negative and extremely large dielectric anisotropy value and a small optical anisotropy value together, to provide liquid crystal compositions comprising the liquid crystalline compound, and to provide liquid crystal display devices fabricated by using the liquid crystal composition; the liquid crystalline compounds have 2,3-difluorophenyl moiety and are expressed by the general formula (1)
wherein Ra and Rb each independently represent a straight chain or branched alkyl group having 1 to 10 carbon atoms in which group any methylene group may be replaced by —O—, —CH═CH—, or —C≡C—, but there is not a case wherein —O— continues; ring A1 represents cyclohexane-1,4-diyl not adjacent any methylene group may be replaced by —O—; ring A2 represents 2,3-difluoro-1,4-phenylene in which phenylene hydrogen atoms at 5-position and 6-position may each independently be replaced by fluorine atoms; Z1 and Z2 each independently represent single bond or —CH2CH2—; Xa, Xb, Xc, and Xd each independently represent hydrogen atom, fluorine atom, or chlorine atom, but at least one of Xa, Xb, Xc, and Xd is fluorine atom or chlorine atom and any atom which constitutes the compound may be replaced by its isotope.
本发明的目的是提供具有负的极差和极小的光学极差值的新型液晶化合物,提供包括该液晶化合物的液晶组合物,并提供使用该液晶组合物制造的液晶显示装置;液晶化合物具有2,3-二氟苯基基团,由一般式(1)表示,其中Ra和Rb各自独立地表示直链或支链烷基,其具有1到10个碳原子,在该基团中任何亚甲基基团可以被替换为—O—、—CH═CH—或—C≡C—,但不存在—O—连续的情况;环A1表示环己烷-1,4-二基基团,不与任何亚甲基基团相邻,可以被替换为—O—;环A2表示2,3-二氟-1,4-苯基基团,其中苯基氢原子在5位和6位上各自独立地可以被氟原子替换;Z1和Z2各自独立地表示单键或—CH2CH2—;Xa、Xb、Xc和Xd各自独立地表示氢原子、氟原子或氯原子,但至少其中之一为氟原子或氯原子,并且构成该化合物的任何原子都可以被其同位素替换。