Study on speckle problem in semiconductor laser display

Abstract

As a new generation of display technology, Laser displays a wide range of color gamut, high brightness, and other characteristics. However, as a highly coherent light source, laser speckle will be generated by the interference phenomenon of the reflected light or transmitted light of different surface elements after the incident on the surface of the object, which will seriously reduce the quality of the display image. Therefore, the suppression of laser speckle and the reduction of speckle contrast are always important problems in laser display technology. Here, we presented a speckle suppression scheme suitable for projector optical systems. Speckle suppression by spectral broadening and speckle suppression by superposition of multiple independent and unrelated speckle patterns are included in the scheme. Then, the feasibility of the scheme was verified by simulation. On this basis, the projector system was built. The speckle suppression scheme was added, and the effect of the scheme on speckle contrast was verified by actual measurement, and the speckle contrast was successfully reduced from 0.129 to 0.041, which was difficult for human eyes to distinguish.