Patent ID: 8770763

Claim:
A projection display device which displays an image by projecting the image on a screen, comprising: at least one light source outputting coherent light; a display device forming an image to be displayed on the screen in an area illuminated by a luminous flux from the light source; a first diffusion unit diffusing the luminous flux; a second diffusion unit diffusing the luminous flux, wherein: the first diffusion unit is provided in at least one of a light source conjugate position and the vicinity of the position in an optical path of an optical system including the light source through the screen; the second diffusion unit is provided in at least one of a display device conjugate position and the vicinity of the position in the optical path of the optical system; the optical system including the light source through the screen comprises: an optical system for illumination propagating the luminous flux emitted from the light source into a predetermined optical path and leading the luminous flux toward the screen; and an optical system for projection scaling up and projecting the image formed in the illuminated area of the display device; the display device forms an image to be displayed on the screen in the area illuminated by the luminous flux lead by the optical system for illumination; the first diffusion unit is provided in at least one of the light source conjugate position and the vicinity of the conjugate position in the optical path of the optical system for illumination; and the second diffusion unit is provided in at least one of the display device conjugate position and the vicinity of the conjugate position in the optical path of the optical system for illumination; and a luminous flux intensity leveling unit leveling intensity of a luminous flux, wherein: the luminous flux intensity leveling unit is provided in the optical system for illumination, a luminous flux incident surface of the luminous flux intensity leveling unit has a conjugate relationship with the light source, a luminous flux emission surface of the luminous flux intensity leveling unit has a conjugate relationship with the display device; the first diffusion unit is provided in the position of the luminous flux incident surface or the vicinity of the position; and the second diffusion unit is provided in the position of the luminous flux emission surface or the vicinity of the position.