Speckle suppression method with vibrating light pipe

Speckle effect severely affects the laser projection image quality, therefore it needs to be suppressed. A speckle suppression method with a vibrating light pipe is proposed. It is theoretically analyzed, and the effectiveness is verified by simulations and experiments. Experiments are performed with two typical laser sources. The results show that, with the proposed method, no additional reforming lens is necessary for efficient rectangular illumination, which reduces the system size; the vibrating light pipe method can effectively reduce the speckle contrast to less than 6%, which is not recognizable to human eyes; the illumination efficiency of the speckle suppression system is above 90%.