In order to improve the imaging quality of the existing projector and simplify the optical path structure of the projection system, this paper involves a new type of optical system of projection system, using three-color LD light source as illumination source of projection system, using tapered light guide tube as the light guide. This article studies the principle of diffusers to suppress speckles, and derives the influence of diffuser number, divergence angle and gap between diffuser on speckle contrast. Using the Tracepro to build a three-dimensional model. The optical path structure was simulated and the results of simulation were analyzed. It shows that the speckle contrast of the projection system is 5% and the spot uniformity is up to 95.8%. Compared with the traditional laser projection light path, reduce the color wheel、Color-combination prism, dichroic mirror, mirrors and other components, simplifies the light path structure.
In this study, a new type of projector light path is designed to eliminate the deficits of existing projection systems, such as complex structure and low collection efficiency. Using a three-color LED array as the lighting source, by means of the special optical properties of a gradient-index lens, the complex structure of the traditional projector is simplified. Traditional components, such as the color wheel, relay lens, and mirror, become unnecessary. In this way, traditional problems, such as low utilization of light energy and loss of light energy, are solved. With the help of Zemax software, the projection lens is optimized. The optimized projection lens, LED, gradient-index lens, and digital micromirror device are imported into Tracepro. The ray tracing results show that both the utilization of light energy and the uniformity are improved significantly.
Currently, the mainstream autostereoscopic displays have a shortcoming: the insufficient brightness. It causes bad influence on the using of autostereoscopic displays. To improve the brightness, a new design method of the backlight module is needed. In this article, one high-brightness light emitting diode (LED) is used, and the light is concentrated to the eyes of observer by using a Fresnel lens and many cylindrical lenses. The brightness is improved significantly. When the user position changes greatly, another LED is lighted up to replace the former. Imitation and experimental results indicate that this method is feasible. Compare with previous backlight modules, this backlight module is brighter and need less electrical energy, and is more suitable for cockpits.