Patent ID: 6654080
Filing Date: 2003-11-25
Classification: G02F

Abstract:
A reflective liquid crystal display device comprising:first chiral nematic liquid crystal material comprising liquid crystal having a pitch length effective to reflect visible light of a first color, second chiral nematic liquid crystal material comprising liquid crystal having a pitch length effective to reflect visible light of a second color, and third chiral nematic liquid crystal material comprising liquid crystal having a pitch length effective to reflect visible light of a third color, the liquid crystal of said first material, said second material and said third material having positive dielectric anisotropy; planar substrates that form therebetween a first region in which said first material is disposed, a second region in which said second material is disposed and a third region in which said third material is disposed, wherein said first region, said second region and said third region are stacked relative to each other and each of said first material, said second material and said third material extends continuously from near one of said substrates to near an adjacent one of said substrates; wherein said substrates cooperate with said first material, said second material and said third material to form in said first region, said second region and said third region, scattering focal conic and reflecting planar textures that are stable in the absence of a field; wherein incident light travels in a direction sequentially through said first region, said second region and said third region, said first region being closest to the viewer, comprising a light absorbing back layer disposed downstream of said third region relative to said direction of incident light; wherein the incident light is reflected by the planar textures of said first region, said second region and said third region such that reflected light leaving the display exhibits a color that is an additive mixing of combinations of said colors which are reflected from said planar textures, and said incident light passing through said first region, said second region and said third region is absorbed by said light absorbing back layer; and addressing means for applying an electric field for transforming at least a portion of the liquid crystal of at least one of said first material, said second material and said third material, to at least one of the scattering focal conic and reflecting planar textures.