Patent ID: 8085369
Filing Date: 2011-12-27
Classification: G02F

Abstract:
1. A quasi-homeotropic liquid crystal device including a layer of nematic liquid crystal material, the liquid crystal device operable in response to a drive signal to switch to liquid crystal director field states between ON and OFF liquid crystal director field states and configured to self-compensate for in-plane optical retardation in the OFF director field state, comprising: a first electrode structure on which is placed a first alignment layer having a surface conditioned to define on it a first projected alignment direction and a second electrode structure on which is placed a second alignment layer having a surface conditioned to define on it a second projected alignment direction, the first and second alignment layer surfaces spaced apart from each other and arranged to form a liquid crystal cell that has the first and second projected alignment directions set at an offset angle relative to each other and that operates as characterized by a contrast ratio associated with the ON and OFF director field states; a layer of nematic liquid crystal material captured between the spaced-apart first and second conditioned alignment layer surfaces, the nematic liquid crystal material having alignment layer surface contacting directors and alignment layer surface noncontacting directors and characterized in part by an intrinsic twist property; the alignment surface contacting directors anchored at surface pretilt angles relative to the first and second conditioned alignment layer surfaces and the alignment surface noncontacting directors establishing a cell twist angle determined by the offset angle and the intrinsic twist property of the nematic liquid crystal material; and the surface pretilt angles and cell twist angle set at values that, in combination, contribute to establish a cuspate singularity in the contrast ratio in response to a value of the drive signal switching the liquid crystal device to the OFF director field state providing self-compensation for in-plane optical retardation.