Patent ID: 8274736

Claim:
A transmission-type screen for displaying an image onto which image light from a light emitter is radiated from a rear-surface side thereof, which is an opposite side to an image display side, the transmission-type screen comprising: a Fresnel optical element that inflects the image light from the light emitter toward the display side using a prism formed on a rear-surface side thereof, which is a light-entering-surface side of the image light; a first substrate that holds the Fresnel optical element; a first light diffusing unit that is provided on the display side with respect to the Fresnel optical element and diffuses the image light from the Fresnel optical element; a second light diffusing unit that is provided on the display side with respect to the first light diffusing unit, diffuses the image light from the first light diffusing unit, causes the diffused image light to exit toward the display side, and is configured to change a relative position thereof to the first light diffusing unit, the relative position being changed such that a moving light diffusing unit of the first light diffusing unit and the second light diffusing unit is moved in a circular path with respect to a stationary light diffusing unit of the first light diffusing unit and the second light diffusing unit, the circular path being parallel to a plane of a surface of the moving light diffusing unit, and a degree of haze of the moving light diffusing unit is less than a degree of haze of the stationary light diffusing unit; and a second substrate that is provided on the display side with respect to the second light diffusing unit and holds the second light diffusing unit.