| 摘要 |
PURPOSE:To make magnifications continuously variable with relatively simple construction by using a projecting lens of a fixed focus without using any zoom lens. CONSTITUTION:A microfilm 3 illuminated by a lamp 1 is projected to a photosensitive drum 9 by a projecting lens 4 of a fixed focus and mirrors 5-8. The mirrors 6, 7 are disposed mutually at right angles, and reflect the optical axes of the projection light incident thereto in such a way as to be reversed in directions in the same direction. The mirrors 6, 7 form an optical system 8 for adjusting optical path length, are held integrally in a mirror holder 9' and are moved by a micromotor 12. Further, the lens 4 is moved on the optical axis of the projection light by a micromotor 14. The lens 4 is made interchangeable with lenses 4' of different fixed focuses. If the machine is constituted in this way, magnifications are varied continuously with the relatively simple construction by using the projecting lens of a fixed focus. |
