Patent ID: 7950808

Claim:
A projection display apparatus that performs an image display by projecting an image onto a screen, the projection display apparatus comprising: at least one light source that emits a coherent light flux; an illuminating optical system that propagates the light flux from the light source into a predetermined optical path to guide the light flux to the screen; a reflection-type light modulating unit that forms an image to be displayed on the screen on an illumination area illuminated with the light flux that is guided by the illuminating optical system; and a projecting optical unit that projects the image that is formed on the illumination area onto the screen in a magnifying manner, wherein the illuminating optical system includes a diffusing unit that diffuses the light flux from the light source, the diffusing unit being located at or near a position that is optically conjugate with an incident aperture of the projecting optical unit, a light-intensity equalizing element that equalizes an intensity distribution of the light flux from the light source, and a relay lens group that leads the light flux from the light-intensity equalizing element to the reflection-type light modulating unit, the position is near the relay lens group, and the relay lens group includes the diffusing unit.