Laser Speckle Suppression in Augmented Reality Displays Based on Static and Low-Loss Polymer-Stabilized Liquid Crystal Screens

Abstract

Laser speckle caused by high coherence severely affects the image quality. The traditional optical approaches cannot effectively suppress speckles without compromising the coherence of the laser in the optical path. In this study, we develop a method in which a novel polymer-stabilized liquid crystal screen (PSLCS) was used to display images for efficient speckle suppression while preserving the coherence and high brightness of lasers. The scattering-induced fluctuations in the intensity of the light reflected from the PSLCS are evaluated to reveal decorrelation variation. The optimal parameters for suppressing speckles and obtaining a clear and high-resolution image via both laser projection and AR imaging are identified by adjusting the driving parameters. A speckle suppression efficiency of 67.34%, which exceeds that achieved by other similar methods, was achieved without using any additional optical elements. An experiment was implemented for verifying the performance of multi-plane AR imaging by a PSLCS, which, to our knowledge, is the first study to investigate the image quality and speckle suppression effect in AR imaging. The proposed cost-effective laser speckle suppression method enables high quality imaging, offering new possibilities for the application of LC-based optical materials and devices in display technology.