Process for forming silicon lc pixel cell having planar alignment layers of uniform thickness

Abstract

A pixel cell array for a reflective silicon light valve features a planar surface alignment layer of uniform thickness over the active pixel electrodes. The surface alignment layer is formed by flowing and curing multiple quantities of alignment material. A first quantity of low viscosity alignment material is spun over the surface and settles into trenches between the raised active pixel electrodes. Curing of the first quantity of alignment material forms a lower alignment layer in the trenches, reducing topography offered by the array surface. A second, larger quantity of higher viscosity alignment material is then spun over active pixel electrodes and the lower alignment layer. The second quantity of alignment material is then cured to form a surface alignment layer. Because of reduction in topography of the array surface by the lower alignment layer, the surface alignment layer is both substantially planar and of uniform thickness across the surface of the active pixel electrode. Each of these properties improve the resolution of the pixel cell by reducing misalignment of the LC attributable to topography offered by the surface alignment layer.