Cholesteric liquid crystal composition, circularly-polarized light separating sheet and methods for production thereof

摘要

A cholesteric liquid crystal composition homogenously having a desired pitch length and pitch gradient and capable of giving a layer having a broad selective reflection bandwidth; a circularly-polarized light separating sheet having the broad selective reflection bandwidth and capable of being produced simply and homogenously; and a method for producing such a sheet. A cholesteric liquid crystal composition which contains a nematic liquid crystal compound having a reactive group, contains a chiral agent, has a &Dgr;n value of 0.18 or more and has an absolute value of a temperature dependency parameter δλ represented by δλ={(2(λb−λa)/(λb+λa)}×{100/(b−a)} (a and b represent the temperature (° C.), λa represents a selective reflection center wavelength at a ° C. and λb represents the selective reflection center wavelength at b ° C.) of 0.50 or less at a=25 and b=100; the circularly-polarized light separating sheet having a cured layer of the composition and the selective reflection bandwidth of 300 nm or more; and a method for producing the sheet using said composition.