Dlp Projectors Based On Led Lighting System

LED source instead of the traditional source was used in the DLP projector. Miniature and long lifetime is the development trend of the projection display. In the recent years, the development of the LED technology makes the possibility to develop longer lifetime and miniature projection display. Compared to the traditional sources, the LED has many advantages, but at the same time, it has disadvantage too. The optical power per unit of Etendue (luminance) of an LED is significantly lower than that of e.g. an UHP-lamp. So how to improve the light transmission efficiency becomes a problem to deal with. And the LED are different form the traditional sources that the conventional illumination systems are not suitable for the LED. So it is necessary to develop new illumination systems. In this paper, the theory of non-imaging optics is introduced into the design of projection system.Chapter 1 gives a brief introduction of the projection display technology, and three typical kinds of the projection system: CRT, DLP and LCoS projection display are introduced. And the standard to weigh the projection is mentioned. 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 compare the LED source with the traditional source and present the recent development of the LED projection display.Chapter 2 studied non-imaging optical systems. It introduced origins of the non-imaging optical theories and it difference to the imaging optical theory. It discussed maximum concentration ratio and Etendue.Chapter 3 introduced the optical and electrical characteristic of the LED used in this paper and made a brief introduction of the color wheel. Finally design drive circuit of LED.Chapter 4 discussed two illumination method that is rectangle light pipes and tapered light pipes. The software LightTools is used to make simulation. The relationship between the length and the uniformity are discussed. Finally the tapered light pipes are designed to be up to the mustard. Chapter 5 introduced the CPC design basing the edge-ray theory, and according to the LED source used in this paper, the improved method is proposed.Chapter 6 introduced the DLP projection display system, and discussed and operation principle of DMD. The two Optical System Architectures are introduced, that is Telecentric Optical-System and Nontelecentric Optical-System. Made the simulation of the whole system.Chapter 7, gives a brief conclusion to this thesis and predicts room to improve the design.