Patent ID: 8403494

Claim:
A projection-type display apparatus comprising: a transmission-type screen configured to display an image projected on a backside thereof; a light source configured to emit a laser beam; an illuminating optical system configured to propagate the laser beam into an optical path; an image displaying device configured to be illuminated in an illuminated area thereof by the laser beam propagating through the illuminating optical system and to form an image in the illuminated area; and a projection optical system configured to magnify the image to obtain a magnified image and to project the magnified image on the backside of the transmission-type screen, wherein the projection optical system is constituted so that a product of an F-number and a projection magnification of the projection optical system is less than 400, wherein the transmission-type screen includes: a Fresnel lens configured to convert an incident laser beam into a substantially parallel light and to output the parallel light; and a lenticular lens configured to convert the parallel light into a diffused light, and wherein: the Fresnel lens has a first light diffusion layer that diffuses the incident laser beam and outputs the diffused light as a first diffused light, the lenticular lens has a second light diffusion layer that further diffuses the first diffused light and outputs the diffused light as a second diffused light, a haze value of the first light diffusion layer is smaller than that of the second light diffusion layer, and the haze value of the first light diffusion layer is at least 72% and the haze value of the second light diffusion layer is at least 80%.