POLARIZED LIGHT ILLUMINATOR

摘要

PROBLEM TO BE SOLVED: To provide a polarized light illuminator by which each part is uniformaized even with respect to the light of a white color. SOLUTION: The diffracting direction of diffraction optical devices 15 and 16 composed of an optical medium including liquid crystal and a polymer is symmetrical with respect to the optical axis, and the diffraction angle in the vicinity of the optical axis is made larger than that of a peripheral part. The wavelength dependency of the diffraction angle is compensated by the two devices 15 and 16. Thus, the adverse effect of the wavelength dependency of the diffraction angle is eliminated and also light utilization efficiency is improved. When the deflection illuminator is used as the back light of a light crystal display device, its size and other optical devices are further modified.