Schlieren optical system using liquid crystal phase gratings for large screen projection

Abstract

The use of a schlieren optical system incorporating liquid crystal phase gratings is discussed with particular regard to large screen projection, and in the context of other projection principles that are currently in use or under development. While certain aspects of this approach have been published elsewhere, the objective of this paper is to investigate the idea in a more comprehensive way and to look at the associated difficulties and limitations. Problems concerning the illumination system are discussed; tendencies and limitations.of several parameters are analysed and are demonstrated by examples. The principle of the liquid crystal phase modulator is discussed using a simple (though mathematically incomplete) model to make the basic effect understandable. Measurements on a simple experimental set-up are presented that show the validity of some of the prior calculations and the problems involved with the requisite small liquid structures.