Patent ID: 8511836

Claim:
A diaphragm apparatus for projectors comprising: a base plate arranged on a lateral position of a light path of light from a light source with one surface facing toward the light path; a main shaft vertically arranged on one of the surfaces of the base plate; a sub shaft vertically arranged on the plane in which the main shaft is vertically arranged at a position off an imaginary line which passes through the vertically arranged position of the main shaft and parallel to the center line of the light path; a main operation member rotatably installed to the main shaft; a main divided blade integrated with the main operation member, the main divided blade moving along a circular track centered at the main shaft, and reciprocally moving in the light path; a sub operation member rotatably installed to the sub shaft; a sub divided blade integrated with the sub operation member, the sub divided blade moving along a circular track centered at the sub shaft, and reciprocally moving in the light path; and a link member, a first end of which is rotatably installed to the main operation member and a second end of which is rotatably installed to the sub operation member, the distance from the sub shaft to the second end of the link member being longer than the distance from the main shaft to the first end of the link member; wherein the main operation member and the sub operation member are configured to be rotated in the same direction by an electromagnetic actuator such that the superposed area of the main divided blade and the sub divided blade varies.