The Study Of The Ilumination System In LED Project Display

Miniature and longer lifetime is the development trend of the micro-display projection system. In the recent years, the production of the high brightness LED provides possibility to develop longer lifetime and miniature micro-projection display. Compared to the traditional sources, the LED has the irreplaceable advantages of high efficiency, no infrared irradiation, small size, low power consumption and long lifetime. But the layout and the luminance distribution of the LED are so different from the traditional sources that the conventional illumination systems are not suitable for the LED especially for the miniature style. So, it is meaningful and necessary to develop new illumination systems for the mini-type LED projectors.In the beginning of the dissertation, three typical kinds of the projection system: TFT-LCD, DLP and LCoS projection display are introduced including the background, category and the optical structures. In addition, the principles and optical technologies in the traditional illumination system are introduced such like the light pipe system and the refractive fly-eye system. Finally the recent development of the LED projection display and the disadvantages are presented.In the second chapter, the principle of the non-image theory, which consists of the etendu principle, the principle of the energy efficiency of the illumination system is introduced, and then the principles of critical illumination, Kholer illumination are illustrated detailed.The third chapter introduces the basic theory of the high brightness LED and their structure characteristics. Design the thermal method and measure the luminance distribution of the LED produced by the Lumileds and the Osram in order to make model in the further illumination system design.In the forth chapter, the design of the reflective fly-eye is proposed. The theory, the design method, the simulation of the ASAP and the analysis result are brought forward. Because of reflection, the structure has smaller volume, free of the chromatic aberration and refractive loss. In addition, the uniformity and the efficiency are both satisfied.The fifth chap puts forward the light pipe and the condenser design, it focus on the influence to the efficiency of the system, such as the arrangement, quantity of the LEDs, the F/# of the condenser, the aperture of the light pipe and so on. This system is suitable for the multiple LEDs, and 1 OOnit brightness is got on the screen finally.The sixth chap introduces the CPC design basing the edge-ray theory. Through the simulation, the calculation, and analysis to the angle of the rays, the improved method is proposed.In the final chap, the paper compares the three methods. The conclusion and future research direction are given.