Patent ID: 6900865
Filing Date: 2005-05-31
Classification: G02F

Abstract:
1. A liquid crystal device comprising: a layer of twisted liquid crystal having a first surface director orientation oriented in a first direction at a first surface of the layer and a second surface director orientation oriented in a second direction at a second surface of the layer, the first direction being different from and non-perpendicular to the second direction; an achromatic combination retarder arranged to compensate for a residual retardation of the layer with a first finite applied field across the layer, the achromatic combination retarder comprising a half waveplate and a retarder whose retardation is equal to x·(λ/4), where x is a parameter whose value is preselected and x≠1, the achromatic combination retarder having an optic axis which is substantially parallel or perpendicular to the bisectrix of the first and second directions; and a reflector for reflecting light transmitted through the layer.