Study Of Scattering Problem In Semiconductor Laser Display

With the constant development of the research on laser,the advantages of laser display are gradually reflected.The monochromaticity and narrow spectral line width make the laser has higher imaging color saturation,more colors,wider color gamut and is brighter than the traditional light source.However,the development of laser display also faces some difficulties.Caused by the high coherence of the laser beam,laser scattering may reduce the image quality and hinder the development of laser display.Therefore,the study of laser scatter and scatter suppression are widely researched in this field.In this thesis,a projection lighting system are designed for laser projection display.The optical components used in the system are simple and small,which can be well used in the projector and maintain great light efficiency.In this system,a compound speckle suppression scheme is designed for the cause of laser speckle,including diffusion wheel,diffusion plate and mixed light source.The system can reduce the speckle contrast of white field from 0.132 to 0.035,which is below the recognition limit of human eyes.The researches in this thesis are as follows:1.The thesis introduces the development of laser display in display technology and explains the advantages and the potential of future development of laser.The thesis further introduces the projector system from the classification of display chip and light source,and introduces the speckle problem caused by laser as light source.2.The thesis introduces the concept of the laser speckle and the forming cause of laser speckle and the previous researches on speckle are summarized from the two ways of speckle suppression.The statistical characteristics and superposition principle of speckle are further analyzed mathematically to provide theoretical basis for the method of speckle dissipation.3.A lighting system with diffuser,diffuser and mixed light source is designed.The system can combine light path and projection lens well in Lighttools and ensure efficiency on DMD(Digtial Micromirror Devices)and uniformity on the screen.The optimization of light intensity distribution by this method is simulated,and the feasibility of speckle suppression was verified.An experimental platform is built for further testing.The speckle contrast of diffuser with different angles is measured by speckle measurement method at different positions,and the illuminance uniformity and brightness of the screen under corresponding conditions are also measured.