Patent ID: 8061855
Filing Date: 2011-11-22
Classification: G02B,G03B

Abstract:
1. A projection apparatus, comprising: an image display element for modulating illumination light; an illumination optical system for irradiating the image display element with the illumination light; a projection optical system for projecting the illumination light modulated by the image display element onto a projection surface, the projection optical system including: an optical system changing section for changing the illumination optical system based on the aperture diameter of the projection variable-aperture diaphragm, wherein the optical system changing section changes the illumination optical system when the aperture of the projection variable-aperture diaphragm changes from a first size to a second size smaller than the first size, so that an amount of light which pass through an area corresponding to the aperture of the second size is greater than before changing the illumination optical system.