Evaluation and configuration of light sources with suppressing speckle and maintaining color gamut in laser displays

Light sources are crucial in laser displays, directly influencing color gamut performance and speckle characteristics. Besides broadening the laser spectral width for speckle suppression, alternative blending schemes for light sources have been proposed to address the challenges associated with spectral broadening. Although these light source configurations enhance speckle suppression, they negatively impact the monochromaticity of the primary colors. By comprehensively considering the speckle suppression effect and color gamut performance, the evaluation factor F has been proposed to determine the optimal configurations of light sources. The optimal spectral bandwidth and blending ratio were obtained by utilizing the evaluation factor. Furthermore, considering the luminance limitations, the scenario with a significant luminance difference between lasers and LEDs was discussed. In the laser-LED blending scheme constrained by luminance limitations, the optimal blending ratios of red and blue primary colors were determined, while green LED was not advisable. Moreover, the speckle suppression effect of laser-LED blending scheme was experimentally validated and found to be influenced by screen scattering. These findings can provide theoretical guidance for the evaluation and configuration of light sources in laser displays.