4‐1: Invited Paper: Effective Speckle Reduction in Laser Projection Systems Using a Low Cost Screen with Multilayer Structure

Abstract

Speckle is undesirable and inevitable in laser projection systems. Current methods to reduce the speckle, such as multiple wavelength laser, moving diffuser, etc., required additional part, which increase the systems cost. Herein, we reported a low cost and simple technique to reduce the speckle in laser projection system by using a screen with multilayer structure (we named it as speckle reduction screen). In our case, this screen is composed of a high reflection layer, a high transparent layer and a particle arrays layer of microspheres. A diffuse mechanism can be provided by the particle arrays layer of microspheres in this method to reduce speckle. The introduction of a particle array layer can effectively enhance the speckle homogenization by increasing the speckle amount, thereby reducing speckle contrast and resulting in a more blurred speckle pattern. Compared to the standard white projection screen, the speckle contrast ratio of the speckle reduction screen dramatically decreases about 60% under the illumination of RGB laser.