| 摘要 |
PURPOSE:To eliminate irregularities in light condensation due to light condensing optical system and lighting irregularities due to the projection of the element wires of optical fibers and to make it possible to provide uniform arc shaped slit lighting, by providing an optical fiber bundle having an incident end, where the optical fibers are bundled, and an output end, where the fibers are aligned in an ring pattern, and providing a driving system for rotating said optical fiber bundle. CONSTITUTION:The light from a mercury lamp 8, which is a light source, is condensed at an incident end 11 of a rotating optical fiber bundle 10 by way of elliptical reflecting mirror 9, which is an optical condensing system. The light is outputted from an output end 12, which is aligned in a ring shape, through the optical fibers. The light is partially screened with a light screening plate 13. The light becomes an arc shaped slit pattern, and a mask 14 is lighted. At this time, the optical fiber bundle 10 is rotated and driven with a morot 15. Irregularities in light condensation at the incident end 11 and the images of the element wires of the optical fibers are projected. The lighting irregularities caused by the projection are averaged during exposure period. The effect is eliminated as the result of the exposure of a substrate. Thus the uniform arc shaped slit lighting is provided. |
