| 摘要 |
PROBLEM TO BE SOLVED: To provide a variable diaphragm mechanism constituted such that lubricant applied on the surface of an aperture blade hardly peels off and also the lubricant is not decomposed by light. SOLUTION: The variable diaphragm mechanism is constituted by placing ten aperture blades 1 to overlap each other. Each aperture blade 1 is rotated with a fulcrum 2 as a center, and an oblong hole 3 is formed near the end part opposite to the fulcrum 2. And, a movable pin 4 is fitted into the oblong hole 3, and each aperture blade 1 is rotated around the fulcrum 2 in accordance with the position of the movable pin 4, then, the area of an aperture part 5 is varied. Alloy plating containing at least Ni and P is applied on the surface of each aperture blade 1, thereby the lubricant does not come off by the abrasion arising when the aperture blade 1 slides and the optical system is not soiled by the lubricant.
|
