Speckle suppression by a hybrid dual solid-state light source in laser projection

Laser projection has become a new trend in display technology. However, speckle noise due to laser coherence poses a notable hurdle in achieving high image quality. We propose a new, to the best of our knowledge, architecture of a hybrid dual solid-state light source (HDSSL), which consists of RGB lasers and RGB light-emitting diodes (LEDs). Theoretical analysis and experimental results confirm that the HDSSL can effectively suppress speckle noise. Speckle contrast below 4% on a 70 in. projection image at a distance of 1.5 m has been demonstrated, resulting in a lower speckle contrast than the human speckle perception threshold. Furthermore, the research indicates that increasing the proportion of LEDs in the light source reduces speckle noise.