Light source apparatus for electronic endoscope and electronic endoscope

A light source apparatus for an electronic endoscope comprising:

• a light source;
• a rotary shutter having a rotation axis extending parallel with the optical axis of said light source, for one of intercepting and emitting illumination light emitted from said light source toward a light guide, said rotary shutter being provided with a pair of aperture controlling rotary plates, coaxial with each other, which are selectively capable of rotating one of relative to and together with each other, and which are each provided with light interception portions and opening portions alternately arranged in the rotation direction, wherein the combined opening angle of the opening portions of the rotary shutter is varied by a relative rotation of said pair of aperture controlling rotary plates, and wherein the amount of said light emitted is controlled by integral rotation of said pair of aperture controlling rotary plates;
• a first planetary gear mechanism including a first internal tooth gear which is provided coaxial with the rotation axis of said rotary shutter, a first sun gear coaxial with an axis of said first internal tooth gear, and a first planet gear which simultaneously engages with the first internal tooth gear and the first sun gear;
• a second planetary gear mechanism including a second internal tooth gear identical to said first internal tooth gear and coaxial with said rotation axis of said rotary shutter, a second sun gear identical to said first sun gear and coaxial with an axis of said second internal tooth gear, and a second planet gear identical to said first planet gear and which simultaneously engages with said second internal tooth gear and said second sun gear;
• and
• a carrier mechanism which holds said first and second planet gears in a same phase position, with respect to said first and second internal tooth gears, and supports said first and second planet gears so as to relatively rotate;
• wherein one of the first sun gear and the first internal tooth gear of the first planetary gear mechanism is non-rotatably fixed, and the other of said first sun gear and said first internal tooth gear is rotated together with one of said aperture controlling rotary plates by a motor, and one of the second sun gear and the second internal tooth gear of the second planetary gear mechanism is driven together with the other of said aperture controlling rotary plates by a phase difference motor.