| 摘要 |
PURPOSE:To facilitate precise fitting by fixing a lens to a lens holder made of a hard-to-work hard material through an annular lens receive made of an easy-to-work soft material. CONSTITUTION:The lens is held in a lens barrel 1 formed of the hard-to-work hard material, e.g. super invar, stone, glass, etc., by using the lens receiver 2, a lens presser ring holder 3, a lens presser ring 4. The lens receiver 2 and lens presser ring holder 3 are fitted as independent parts to the lens barrel 1 while a gap is left so that the influence of the coefficient of expansion of auxiliary metal is reduced. Then, auxiliary metallic fixtures 2 and 3 used, for example, brass which has a larger coefficient of expansion than the lens barrel 1 and are worked to external diameters which are several mum larger than the internal diameter of the lens barrel 1. Then, the lens barrel 1 is heated and the auxiliary metallic fixtures 2 and 3 are cooled and pressed in; and the lens 5 is inserted and the presser ring 4 is engaged threadably with the lens presser ring holder 3 to fix the lens 5 in the lens barrel 1. |
