Patent ID: 7798959

Claim:
An endoscope light source unit for making illumination light from a light source incident on an incident end face of a light guide connected thereto, said endoscope light source unit comprising: an aperture device having a plurality of aperture openings of different opening ratios, for selectively positioning one of said aperture openings between said incident end face of said light guide and said light source; a reading device for reading information on an illumination light quantity limit from a memory provided in a scope which is connected to said endoscope light source unit; and a controller for selecting an opening ratio of said aperture device in accordance with said information on said illumination light quantity limit read by said reading device, wherein said controller controls said aperture device so as not to position any of said aperture openings, which have an opening ratio higher than said selected opening ratio, between said incident end face of said light guide and said light source; wherein said aperture device comprises a disc and drive device for rotatably driving said disc, said aperture openings of different aperture ratios being formed in said disc at equi-angular intervals thereon about a center of rotation thereof; and wherein said disc further comprises an aperture position hole for detecting an initial position of rotation of said disc.