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The Study And Implementation Of Reducing Laser Speckle And Three-LCOS Laser Projection Display

Posted on:2013-02-24Degree:DoctorType:Dissertation
Country:ChinaCandidate:H LiuFull Text:PDF
GTID:1118330374494189Subject:Communication and Information System
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In recent years, due to the huge demand of the digital TV and broadband network applications etc., the display technology and market is in sharp change and rapid development period. In many of the continuous development of the display technology, the laser display is representing the future development trend and main direction of the display technology, which is the focus of competition. Based on the laser has unique characteristic:high power and low astigmatism. The laser projection can meet the business application and requirements of household for its high display quality, which overcomes the lamp light source's shortcoming. It will replace market share of the original business applications. So, the laser display is a new generation of laser home theater and will become a high-end product of the big screen TV's. Its products have high additional values, and laser projection is one of the important development directions of the display technology. In addition, laser display technology will also be used to public information screen, astronomical observation, water curtain imaging performance and other application of civilian market, etc. which has broad market.This article does a lot of research works on the laser projection, such as the high power laser output, laser radiation, beam shaping, laser cooling, and white balance correction and reducing laser speckles. Finally based on software simulation optimization, we presented the design scheme of the three LCOS laser optical engine, and test the performance of the second prototype.In this paper, the major research results are as follows:Firstly, we introduce the LCOS technology, and its display principle. We tested the performance of the LCOS chip, which will be used in the projection. And we designed the white balance module of the system.Secondly, in the process of frequency doubling, and according to the temperature distribution of PPLN, we have calculated thermal effect in the process of frequency doubling. This work laid a theoretical foundation on laser frequency doubling. We put forward the new coupling scheme.Through a single fiber laser to multiple laser unit, we realize the high power output. And we calculated the coupling efficiency of blue laser and green laser. Thirdly, we discussed the cooling problems of the high power laser. Firstly, we must know the laser module array. And the cooling scheme of light source and discussed several common cooling forms of laser module. We determined the laser cooling method by joining the controller, driving the fan and copper heat conduction.Fourthly, in order to solve the problem of laser speckles, which is an important research topic in the laser display, we have established the laser speckle model, and also simulated the laser speckle by Gaussian rand on surface.This paper gives a certain laser speckle measurement standard through the CCD camera and image processing system by analyzing and quantifying the laser speckle pattern. The measurement standard is the only standard on speckle measurement of laser display. This project summarized reducing speckle methods at home and abroad, and three new schemes of suppressing the speckle noise in images display are proposed.Fifthly, using RGB lasers as the light sources, we designed optical engine of the three LCOS-laser projector. And we designed the LSR module by software solidwork. We processed the first projector and found its shortage. So we optimized and designed the second projector.Sixthly, combined with measurement method of display system, the second prototype was tested. The paper designed and manufactured the diffusers with different diffraction angles, such as5°,10°nd20°. The experiments indicate the diffuser with10°can best performance of reducing the laser speckles. The speckle contrast of the high-power projection system is reduced to4.2%, which is less than5%and achieve the human acceptable range. After test and professional inspection department verified the second prototype, which performance index is high, and the main indexes all reached the requirements of the projector.In conclusion, the above research results in this paper solve key technology problems of the1000lumen level laser projector, which lay the foundation to realize the industrialization of laser projection display. And through the project application, it will drive the fast development of relevant industries. It has important reference value for the research and application promotion of high power laser projector.
Keywords/Search Tags:three primary colors, laser, high power, frequency doubled crystal, thermal effect, laser speckle, optical engine, polarization beam spliter(PBS), fly-eyelens, etendue, LCOS, optical fiber coupling, ferroelectric liquid crystals, CCD camera, LSR
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