| 摘要 |
PURPOSE:To permit collimation from infinity up to close distances by providing a convex lens between an objective lens and a focusless lens and allowing luminous fluxes to focus at a focal plate by the fixed focusless lens. CONSTITUTION:The rays from a close distance point are made into parallel rays by way of an objective lens 8, and these parallel rays pass through a focusing lens 9 and a focusless lens 10, and image on a focal plate 4 via an automatic correcting mechanism 3. This image is visible through an eyepiece lens 5. In the case of infinity, on the other hand, the parallel rays enter the lens 8, and as the lens 9 moves, they pass through the lens 10 and the mechanism 3 and are imaged on the plate 4. With the length of the lens barrel assumed to be the same as that in the conventional process, the short collimatable distance which has been 1.5m in the conventional process is now possible up to 0.3m. |
