Optical modulating element and electronic apparatus using it

摘要

A photomodulation element which uses a color variable filter to obtain the light of a desired wavelength and a liquid crystal element. Light entering the photomodulation element from one side passes through the liquid crystal panel and a second polarizer. The distribution of the transmission light intensity about the wavelength is nearly close to the normal distribution centered on a specific wavelength determined on the basis of the retardation of the liquid crystal panel. Based on the half-value width W necessary in this distribution, the retardation of the panel is determined and the number of the liquid crystal elements is determined so as to obtain a bandwidth which corresponds to the color of the light desired. The retardation of the light crystal is changed by a voltage regulating circuit so that the transmission light intensity distribution at the wavelength of the transmission light of the liquid crystal element is maximized at the desired wavelength lambda o so that the wavelength of the light leaving the photomodulation element may be selected to provide the desired light.