| 其他摘要 | With the rapid development of display technology, large-screen display technology is becoming more maturity and perfect，LCD TV, PDP TV and projection display has become a mainstream. Among them，the projection display occupies the absolute superiority in terms of cost and technology，it has a pivotal position in the field of large-screen display. The requirement of projection display products transforms to personalization, specialization and diversification due to the market developments of display technology, conventional projection display products have been unable to fully meet a series of requirements proposed by consumers, such as big-screen, low-cost, portability, short-focal length, large field of view, ultra-thin, large relative aperture and high-resolution, it is very necessary to design a new large-screen and ultra-thin projection optical system, broaden the application market of the projector which has been almost saturated, open a new chapter in the application of projection display.The specific technical difficulties of large-screen and ultra-thin projection display is: in order to achieve the size of about 100 inch projection screen, projection lens of conventional display device is placed above a distance of 3 meters. It is difficult to keep a large screen meanwhile to further shorten the projection distance objectively. In this paper, a novel catadioptric design only with a piece of aspheric mirrors is proposed to solve the problem of a relatively large throw ration, breaking through the limitations of any space in use of the projector with unlimited business opportunities and development potential.In this program, using a digital micromirror device (DMD) produced by TI Inc. as spatial light modulator, employing hybrid light with laser and LED as a high brightness projector light, the light source is coupled and projected uniformly in the spatial light modulator through the illumination optical system, and an image is enlarged via a special imaging optical system. Based on this program, it needs to fully understand the various components of projection display system, as well as discussing the theoretical basis of geometrical optics on projection lens design and technical indicators used to evaluate the image quality of the projected image.In the design of the imaging optical system, to solve the problem of short projection distance to achieve a large-screen and high-brightness image, we discuss three kinds of structure respectively, such as transmissive projection lens, reflective optical system and catadioptric system in the aspect of aberration correction, the difficulty of processing and testing and application prospects. Finally, using a catadioptric imaging optical system for designing the ultra-thin structure, the system is rotational symmetry but off-axis imaging, an aspheric mirror is employed not only simplifying the system configuration greatly, but also improving the performance of imaging system. Software of Light Tools is used for tracing rays and analyzing the uniformity on the imaging plane, simulation results show that illumination uniformity is very good on the focal plane.In order to further verify the performance of catadioptric projection lens with ultra-short projection distance, the processing and alignment of projection imaging lens were completed taking into account the manufacturing costs and the test level of aspheric surface in this paper, and a experimental prototype was set up matching the existing DLP light source, the size of the image is 65.2 " on the screen at the distance of 102mm. At the same time, the main indicators such as the distortion, brightness contrast, illumination uniformity, etc. were tested with the test instrument, the actual measurements were very close to the simulation results, both meeting the design requirements, the prototype made contributions on the development of "zero distance" and large-screen projection production on a large scale. |
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