Lcd Projector Lighting System

Projection display technology is by far the best way to implement large-screen display, which projects the images information on the micro-displays onto the screen with optical systems to form magnified images. The advantages of projection display are large screen (from 40 to several hundreds inches), high brightness (even more than ten thousands lumen), high contrast and high resolution. Currently, the application of projection display covers from the high-end military command, large conference, to business, education, scientific research, entertainment and other areas. This paper is mostly concentrated on the liquid crystal projection display system.First of all, the background of the projection display, its category and enormous market potential are introduced. TFT-LCD, DLP and LCoS are three main micro-display projection display technologies. Their principles and technical pros and cons are analyzed and compared. In addition, the principles and optical technologies in the optical engine are introduced respectively.Second, the principles of critical illumination, Kholer illumination and fly-eye Kholer illumination are introduced. By analyzing the principles of these three illumination methods, we get the conclusion that fly-eye illumination system could achieve the best uniformity. The point source is used to calculate the uniformity of the Kholer illumination and fly-eye illumination. In this paper, it is discussed that how the number of fly-eyes influence uniformity in the projection system. And how the different arrangements of fly-eyes result in different uniformity is also analyzed. Meanwhile, we also discussed the influence of decentering fly-eyes on the light efficiency. Three decentered fly-eyes architectures are introduced in this paper, which could all increase the light efficiency greatly. This paper also presents a new method for improving the performance of wide screen projection display illumination systems, which introduces cylinder lenses. Results of simulation show that a total increment of about 5% to 10% of the output lumens is available with this improved fly-eye system.Also, the theoretical design method of the light-pipe system is presented. Issues that have to be considered in the procedure of a real light-pipe illumination system are analyzed. The detailed analysis shows that a balance between the section size of the light-pipe and the F/# of the light beam that could be utilized by the following optical system after light-pipe should be reached to acquire best performance.In this paper, we also do some researches in the liquid crystal projection display system design. The system design principle "and procedure are introduced clearly. The simulation results are proved to be true by our prototype projector. After the thorough tests of the prototype projector, we analyze the influence of each optical components in the projection display system, and therefore put forward the ways to improve the performance of the whole system. As for the color parameters analysis,the color temperature combined with minimum perceptible color difference is used to evaluate the white color of a projector, which is much more reasonable.At the end of this paper, the whole work is summarized and the latest trend of projection display is discussed briefly, especially the LED projector.