In this invention, animation effects have been obtained in a device containing a light source illuminating a linear polarizer producing plane polarized light which is rotated in an electro-optical cell/cells such as a Liquid Crystal or PLZT cell. The angle of the plane is changed at the required speed...http://www.google.com/patents/US5020882?utm_source=gb-gplus-sharePatent US5020882 - Electro-optic animated displays and indicators
