| abstract |
An optical modulation device such as an electrical switchable prism, which may be used as a light deflector, or an electrically switchable lens, comprises a volume of liquid crystal material, means for applying electric or magnetic bias fields across the material and means for switching the bias fields to provide a controlled refractive index gradient in the liquid crystal material. The liquid crystal material may be contained between substrates having a set of four or eight electrodes (collectively) on their inner surfaces. |