Patent ID: 7599040
Filing Date: 2009-10-06
Classification: G02F

Abstract:
1. A color liquid crystal display device, comprising: a pair of oppositely disposed substrates each of which is provided with an electrode and has been subjected to homeotropic alignment treatment; and a chiral nematic liquid crystal disposed between said pair of oppositely disposed substrates, wherein said chiral nematic liquid crystal is aligned homeotropically with respect to the substrates when a voltage is not applied between the electrodes, and is aligned twistedly in an angle between the substrates effecting birefringence of said chiral nematic liquid crystal when a voltage is applied between the electrodes, and wherein said chiral nematic liquid crystal has a temperature range in which a helical pitch of said chiral nematic liquid crystal is increased while a local refractive index anisotropy of said chiral nematic liquid crystal is decreased with temperature rise, and the angle of twisted alignment is reduced by the increase of the helical pitch to increase an effective refractive anisotropy so as to offset decrease of birefringence caused by the decrease of the local refractive index anisotropy of said chiral nematic liquid crystal with temperature rise.