| 摘要 |
PURPOSE:To perform precise alignment by increasing the frictional angle of a lens by the linear contact of the edge part of a presser ring with the taper surface of the lens. CONSTITUTION:A step part 3 which holds and forms effective luminous flux from a lens 2 and also mounts it fixedly is formed at one terminal of the internal diameter of a lens frame 1. Further, a thread-cut part 5 which engages threadably the presser ring 4 pressing the lens 2 fixedly is formed at the inner circumference of the other terminal of the lens frame 1. The external diameter of one surface (upper part in figure) of the lens 2 forms the taper surface in the pressing direction of the pressure ring 4, i.e. from the external diameter of the lens 2 to the optical axis (l) so as to attain alighment, and the tape part 6 is inserted upward to abut on the step part 3 at one terminal of the lens frame 1. Further, the taper part 6 of the threadable lens 2 is pressed fixedly at its tip outer circumferential end 7 to the internal diameter thread part 5 of the other terminal of the lens frame 1 while the internal diameter is set to the effective luminous flux diameter of the lens 2 and a thread part is formed at the external diameter part. |
