Patent ID: 6795139
Filing Date: 2004-09-21
Classification: G02B,G02F

Abstract:
A polarizing element capable of separating natural light into reflected light and transmitted light composed of polarized light,wherein a half-reflecting wavelength in each position in a surface of said polarizing element ranges within Â±10 nm relative to a half-reflecting average wavelength, and wherein (i) the half-reflecting wavelength is a wavelength which is located at a long or short wave side of a wavelength exhibiting maximum reflectivity based on a spectrum of reflected light in a predetermined wave range in which the natural light is separated into the reflected light and the transmitted light, and the half-reflecting wavelength exhibits reflectivity of 50% with respect to the maximum reflectivity, and (ii) the half-reflecting average wavelength is an average of half-reflecting wavelengths in a whole surface of said polarizing element, and wherein said polarizing element comprises one of (i) a cholesteric liquid-crystal layer and (ii) a combination of the cholesteric liquid-crystal layer and a quarter-wavelength plate, and said predetermined wave range is from 300 to 1000 nm.