Patent ID: 6188462
Filing Date: 2001-02-13
Classification: G02F

Abstract:
A diffraction grating with an electrical field controlled period comprising a cell with a first cell wall structure and a second cell wall structure, electrodes disposed on facing surfaces of the first and second cell wall structures, a unidirectionally aligned alignment layer disposed on each electrode, and a cholesteric liquid crystal disposed between the first and second cell wall structures, wherein the alignment layer provides an in-plane easy axis of molecular orientation such that the easy axis is one of parallel or tilted with respect to the first and second cell wall structures, and wherein a combination of surface anchoring of the cholesteric liquid crystals on the alignment layer, molecular twist of the cholesteric liquid crystals, and orienting action of the electric field sufficient enough to place the cholesteric liquid crystal in a modulated state with a director orientation modulated in the plane of the cell provides a uniform diffraction grating wherein the period is controlled by voltage of the electric field.