A hybrid temporal and spatial speckle-suppression method for laser displays.

We propose a system that reduces laser display speckles by vibrating the light pipe. A small displacement of the light pipe appears to allow the total reflection of the laser, thereby resulting in a homogenized speckle field that changes with time. In this case, the speckle interference generated by the pattern projected by the laser through the light pipe destroys the spatial homogenization of the laser beams when the light pipe is vibrated. Moreover, when the light pipe begins the sequential vibration, the phases and paths of the beams are changed after the beams traverse the light pipe. Consequently, temporal speckle wavefront superposition can homogenize the luminous intensity distribution of the speckle pattern. This process reduces the speckle contrast to less than 4% while maintaining a luminous intensity of greater than 70%.