Theoretical Research Of Surface Slope Based Optimization And The Corresponding Design Of LED Powered CF-LCoS Optical Engine

With the coming of the age of information, a critical and meaningful research is that people could share their information to anyother one by mobile devices anytime and anywhere. Nowadays, the birth of the embedded pico-optical engine makes efficient information transfer and share possible. In the future, pico-projector market will depend on both the effect and the cost. Undoubtedly, CF-LCoS will be the most potential technology. CF-LCoS pico-projector has the advantages of high-speed response, low-power and low-cost. Unique color reproduction of CF-LCoS technology requires only a single white LED chip as the light source, which has no more need of the complicated color separation or color mix system. CF-LCoS technology could not only minimize the volume of the optical engine, but also reduce the cost. Therefore, it has practical significance that a systematic design theory of the LED based CF-LCoS optical engine can be presented and used to guide the fabrication.The popularity of the LED subverts the design methods of the traditional lighting source. This research focuses on the basis design theory and the application of the LED based CF-LCoS pico-projector, in which surface slope based optimization is presented and considered as a basic method. We present a novel and complete systematic design theory of CF-LCoS pico-projector, which includes multiple freeform surfaces and the non-rotationally symmetric structure based illumination system. The method could not only realize effective and efficient design of CF-LCoS illumination system, but also have universal significance for other LED lighting applications. The contents of the research mainly include the following four parts.Firstly, based on the fundamental theory of single-surface slope based optimization, we present a design method which combines the initialized partial differential equations of the freeform surface and slope based optimization. Based on the method, we realize the plano-convex freeform lens based CF-LCoS pico-projection system. The design theory could laid the theoretical foundation for further study.Secondly, based on the algorithm of predetermined surface deflection angle, we further propose multiple-surface slopes based optimization and realize the synchronized optimization of rotationally symmetric multiple freeform surfaces in the design of CF-LCoS pico-projectior. At the same time, it means that the design method has universal significance for other rotationally symmetric illumination systems.Thirdly, surface slope based optimization method is applied to an illumination system with non-rotationally symmetrical structure. We realize both the designs of elliptic-spot-illumination and rectangular-spot-illumination system in LED based CF-LCoS pico-projectors. Based on the etendue calculation and the edge ray principle, a design theory for elliptic-spot-illumination system in LED based CF-LCoS pico-projectors is presented. We further propose a design method for high-efficiency rectangular-spot-illumination system for CF-LCoS projectors, in which freeform surface design method in three-dimensional space is included.Fourthly, based on the proposed design theory, an embedded CF-LCoS pico-projector is designed and fabricated. We also measure and analyze the performance of the pprojector. The experiment results prove the effectiveness and practicality of the proposed design theory.