Color separation element and image display device using same

Abstract

A color image display device has a light source which emits an approximately parallel beam of light, a color separation element for separating this parallel beam into beams of light of different colors, a liquid crystal display panel having picture elements and a lens array for focusing the separated beams at corresponding ones of these picture elements. The color separation element is formed with a prism array having two diffraction gratings on both sides of it such that a beam of white light passing through it will be separated into beams of different colors and the angles between the optical axes of these beams of different colors will be greater as they leave the separation element than if this beam of white light passed through only one of these diffraction gratings. Either one or both of these diffraction gratings may be integrally formed respectively on one or both of the surfaces of the prism array.

Dependencies are inferred from the claim text.