| dc.description.abstract | Nowadays, the advance of communication systems and portable devices such as the personal digital assistants (PDAs) and mobile-phones enrich our daily life. These communication systems make the transference of video information possible; miniaturization of portable devices lets us watch live programs online anytime, anywhere. lthough the improvement in size of the mobile devices has made much progress, the size of projector devices are still needed significant miniaturizations. Beside their overly large size, the current projectors still have several other disadvantages such as high power onsumption, noisy fans and delay when switching on and off. improvements need to be made in order to match other portable devices. In this thesis, a compact LED light source is used in place of conventional lamps, which makes for power conservation and faster on-off delay time. After combining this light source with a novel TIR prism, projection lens and illumination system , a reduction in the size of the whole system became possible. Moreover, the advantages of LED light source projection systems mean that primary colors can be created by the LED instead of being laboriously filtered from a white light source. The typical color gamut can be as much as above 120% over the sRGB standard [1-3]. In this thesis, we propose a pocket-size projector system with compact size of 75mm × 67 mm × 42 mm. For the LED light source, there are three discrete red, green, and blue (RGB) color LED sources. The size of the light source module is 30mm × 30 mm × 20 mm. The volume of the light source is only 18cm3, meaning a
reduction in the size of the entire light source system of 60% that of a traditional light source module. Beside the volume issue, the collimating lens lets the collecting
efficiency reach to 95 % at the divergence angle of 12.5 degree. For the illumination system, we use the micro lens array as intensity homogenizer. It can not only reduce the total track of illumination system but also reach high
uniformity degree with 93%. For the light separator, we use a novel TIR prism design to replace the tradition TIR prism. The prism is consist of two triangle prisms .The
novel prism can not only reduce the size of light separator but also increase the contrast ratio to 3700: 1 for whole system. For the projecting lens, a compact telecentric lens with a total track of 42mm is also developed. The MTF value of the lens can reach 0.5 at the spatial frequency of 36lp/mm. It will offer a sharpness image quality. The RMS spot size was controlled under 13.6 um2 for all fields. The fale phenomenon can’t be seen for the projected image. The optical distortion and TV distortion were controlled under 0.5%. The distortion phenomenon can’t visible by humen eye. The optical performance of this telecentric lens are better than that of the traditional designs. Moreover, the projection lens and the illumination system are designed independently via telecentric conditions. This thesis supports a detail description about LED projector with the projection lens, LED light source system with collimation parts, novel TIR prism and homogenizer. The efficiency and color performance are also discussed. | en_US |