Design Of Micro LED Projector Based On Color Sequential LCoS

Performance of projector got a lot of progress in the past several years, which can better satisfy market demand of personal consumption. Projection display has arrested more and more attention. Especially, micro-display-chips-based projection displays are emerging as a powerful contender in the consumer projection market.The optical engines of projection display are the main part of the whole projection system, which have directly affect on performance of the system. Design of projection display optical engines includes illumination systems and imaging projection lens. In which the illumination system design is more critical, it determines the quality of the image on screen, including the brightness and uniformity. The shape of micro-display chip is rectangular, so it is the key to obtain a rectangular uniform zone.In this paper the main tasks are as follows:Three typical projection display systems which adopt diffident micro display panels are introduced with the optical structure and the principle. Illuminating system of the projector and the application of LED in illuminating fields were depicted, in addition, the design principle of the illumination system which is based on the non-imaging optics is also studied. Then, several illumination source of projection system are compared, and the features of LED are analyzed in detail. We choose RGB LEDs in this paper, the optical paths of the three color R,B and G both using the same illumination module.Dichroscope is used as co-color components. The R,B and G colors light incidence into the color dichroscope, and is combined into full white light. In order to get the required white light from the R, G, B LEDs, the color matching method by using the actual measurement chromaticity coordinate is also given. Then one illumination method based on the light pipe and magnification lens is adopted. We get suitable parameter through theoretical calculation combining with simulation results.In this letter, we demonstrate a simple and impact illuminating system for the first time which based on the LCoS and LED. According to the principle of the Kohler illumination, we use the simplified front structure of the Kohler illumination system, and use two aspherical lens to collect light from LED. By setting the stop on proper position and optimize them, we got uniform lighting zone on the pupil plane of the optical system. Thus this system is a suitable candidate to be used in the micro-projector's engine because of its outstanding uniform illuminating.