Abstract: A light-transmission viewing screen for displaying an optical image from a beam of light projected thereon along a predetermined path of light provided rearwardly of the screen, the viewing screen having a virtual center axis extending toward a viewer's viewing position, the light-transmission viewing screen comprising a transparent or translucent transmission screen plate through which to transmit the beam of light, and a transmission grating located on at least a portion of one of the surfaces of the transmission screen plate for diffracting the beam of light toward a location substantially aligned with the virtual center axis of the viewing screen when the beam of light is transmitted through the transmission grating.