Patent ID: 6473217
Filing Date: 2002-10-29
Classification: G03B

Abstract:
A diaphragm device comprising: a shutter having a shutter aperture; a small-diaphragm plate having a diaphragm aperture smaller in diameter than the shutter aperture and movable between a first position at which the diaphragm aperture is positioned within the shutter aperture and a second position at which the diaphragm aperture is not within the shutter aperture; an auxiliary plate cooperating with the small-diaphragm plate to cover the shutter aperture and being movable between a first position at which the auxiliary plate is positioned within the shutter aperture and a second position at which the auxiliary plate is not within the shutter aperture; and a diaphragm actuating member for actuating at least one of the small-diaphragm plate and the auxiliary plate; wherein actuation of the diaphragm actuating member in a first direction causes the small-diaphragm plate and the auxiliary plate to be moved to the first positions to cover the shutter aperture, and actuation of the diaphragm actuating member in a second direction opposite the first direction causes the small-diaphragm plate and the auxiliary plate to be moved to the second positions retracted from the shutter aperture.