Fabrication of light-shaping diffusion screens

Abstract

This study presents the fabrication of alight-shaping diffuser, made by recording the far field laser speckles projected from a ground glass on photoresist plate. Elliptical speckles are created by illuminating the ground glass with a line shape He-Cd laser beam. The recorded elliptical speckles can diffuse incident light into different spread angles in vertical and horizontal directions. The speckles are inscribed with the appropriate density and depth on the surface, to diffuse incident light uniformly without a hot spot, by controlling the separation and duration of exposures. A nickel master is then electro-formed from the speckled plate for embossing the pattern on plastic plate for mass production. The diffuser is used in front and rear projection screens with high gain, the displays of ATMs, LED display illumination shapers, LCD backlight and laser beam shaping homogenizers as well as other applications. (C) 2002 Elsevier Science B.V. All rights reserved.