| 摘要 |
PURPOSE:To prevent lens strain due to variation in ambient temperature resulting from the interposition of an elastic member between a lens body and a lens frame or pressure ring by providing a step part to the internal diameter of the edge part of the lens part and fitting this in a collared fitting part provided to the lens frame. CONSTITUTION:A lens storage room 10 formed in the lens frame 1 is a space part larger than the external diameter of the lens body 5, and the fitting part 8 with a frame collar for positioning which engages a lens internal-diameter step part 7 is formed at the inside part. Therefore, the lens internal-diameter step part 7 of the lens body 5 engages the fitting part 8 to position the lens body, which is then fixed to the lens frame with a bayonet type pressure ring 2 through an O ring 9. The bayonet type pressure ring 2 is used, so the lens is held with invariably constant pressure. This constitution prevents lens strain due to variation in ambient temperature and improve the performance of a lens system. |
