Patent ID: 7326451

Claim:
A rotatory polarization plate, capable of extracting a polarized light from an incident polarized light and rotating an azimuth angle of a polarization axis of the incident polarized light, wherein a rotatory polarization angle of the azimuth angle is changed by an incidence angle of the incident polarized light, wherein the azimuth angle of the polarization axis of linearly polarized light is rotated by about 90° when, in the normal direction, the linearly polarized light passes through the rotatory polarization plate, and being rotated by about 0° when, at the incidence angle larger than 30°, the linearly polarized light passes through the rotatory polarization plate, wherein the rotatory polarization plate is formed with a cholesteric liquid crystal layer, and wherein all of a selective reflection wavelength band of the rotatory polarization plate is in a wavelength region longer than 610 nm.