Patent ID: 7419450

Claim:
A light source apparatus for an electronic endoscope comprising: a light source; a rotary shutter for intercepting or emitting light emitted from said light source toward a light guide, said rotary shutter including a pair of aperture controlling rotary plates having axes coaxial with each other and extending parallel with an optical axis of said light source, which are selectively rotatable one of relative to and together with each other and each includes light interception portions and opening portions alternately arranged in a rotation direction, wherein a combined opening angle of said opening portions of said rotary shutter is varied by a relative rotation of said pair of aperture controlling rotary plates, wherein the amount of said light emitted from said light source is controlled by varying said combined opening angle, and wherein said controlled amount of said light is emitted through said rotary shutter by integral rotation of said pair of aperture controlling rotary plates; and a mechanical stop device, positioned between said pair of aperture controlling rotary plates, for limiting the range of relative rotation angle between said pair of aperture controlling rotary plates to a predetermined range from a maximum opening angle to a minimum opening angle.