| 摘要 |
PURPOSE:To perform focusing with a high magnification by dividing the objective lens to two lens groups and moving one of them integrally with a fiber handle. CONSTITUTION:The objective lens is divided to a front group L1 and a rear group L2. The rear group L2 is moved integrally with an optical fiber handle 1 while its spacing d0 is being held constant to change the spacing between the front group L1 and the rear group L2, whereby focusing is accomplished, and at the same time if the focal length of the front group L1 is let to be f1 and the focal length of the entire system to be (f), the following conditions, f<f1<2<1/2>f are satisfied. Then, if focusing to a proximate object is performed by moving the rear group L2 and optical fiber handle 1 integrally in the direction going away from the front group L1, then the main rays enter the optical fiber handle 1 at a small angle and the rate of magnification to the proximate object becomes larger. |
