US Patent 7742230 Projection display-use screen and projection display system optical system

To realize a diffusion film in which arbitrary control of the diffuse light intensity distribution characteristics, and an angular range of diffusion does not change with respect to an incoming light from a specific angular range and a light-outgoing direction converting element that is high in efficiency of conversion of the outgoing direction, and has no limit in the angle of conversion of the outgoing direction, and to provide a thin-model high-quality projection display using the same as a screen.