| 摘要 |
PROBLEM TO BE SOLVED: To provide a plastic housing whose actuation failure due to temperature difference is eliminated without making the sliding diameter of a diaphragm plate have a clearance obtained by expecting the contraction of a housing. SOLUTION: The housing 1 has the sliding diameter 1a of the diaphragm plate and the press-fit diameter 1b of an aperture plate. A diaphragm blade 3 has projections 3a on the front side and projections 3b on the back side, and the projections 3a are inserted in nine holes 4a formed on the plate 4 in a rotatable state, and the projections 3b are inserted in a state where they can slide in the cam grooves 2a of the plate 2. When the plate 2 is rotated centering around an optical axis in the housing 1, the diaphragm blade is interlocked with the rotation through a cam, so that the blade is opened/closed and the diaphragm diameter is changed. By setting the plate 4 and 1b of the housing 1 to be press-fit or transition-fit, the contraction of the housing 1 at low temperature is prevented and the actuation clearance of the plate 2 is secured.
|
