| 摘要 |
PROBLEM TO BE SOLVED: To provide a rigid endoscope facilitating embedding of interval rings into a relay lens frame by forming the interval rings into such shapes that the interval between both leses sandwiching the interval rings are not changed, when the interval rings are inversely arranged in the front/rear direction. SOLUTION: Two interval rings 22, 23 sandwiched between a convex lens face and a concave lens face are formed into ring shapes and internally fitted in a relay lens frame 8, and when they are cut by planes including the axes, the sectional shapes are formed into projecting shapes so as to become symmetric (bisymmetrical shape in the Figure) in the side facing to the convex lens face and the side facing to the concave lens face. The interval rings 22, 23 have no front/rear directivity so that, when the direction of the front/rear of the interval rings 22, 23 is inverted on the way to be inserted into the relay lens frame 8, the interval between both lenses which are adjoined to each other across the interval rings sandwiching them are not changed so that they can be assembled at prescribed intervals. The interval rings 22, 23 can be thus inserted into the relay lens frame 8 and assembled without paying any attention on the front/rear direction and inversion on the way to be inserted therein. |
