JPS5713401A - Diffusing plate - Google Patents

Abstract

PURPOSE:To improve Moire phenomenon and chromatic phenomenon by configuring micro-lens-shaped curved surfaces having irregularly disposed unevenness on surfaces two-dimensionally, and connecting said surfaces with smooth curved surfaces. CONSTITUTION:A lens 13 is made its peripheral part 14 by a frosted glass. Onto a recording face 10, entering three parallel luminous fluxes, which are converted from spherical waves from three pinholes 81-3 through the lens 13, and a Luminous flux, which are converted from said spherical waves through the part 14 and form a very small and irregular spot pattern, then these fluxes interfere each other, so that a pattern formed by overlapping synchronous structure and random structure each other is recorded on the face 10. Pitch in an interference fringe depends on spacing among three pinholes and a spacing between the pinhole and the lens 13; and an average size of said random structure depends on a disposition of the lens and the recording face, therefore, ratios of these dimensions are prepared into various magnitude of a pitch in said fringe. Further, for the diffusing plate, about 10-several tens mum of size is preferable in order to keep its performance.