| 摘要 |
<p>PURPOSE:To obtain the objective lens usable in the ultraviolet ranges and far ultraviolet range at low cost by arraying 1st - 3rd specific lenses at specific air intervals from the object side to the image side in this order. CONSTITUTION:The 1st - 3rd lenses are arrayed at the specific air intervals from the object side to the image side in this order. The 1st lens 11 is a positive-power meniscus lens which is made of quartz or fluorite and has a concave surface 11a on the object side, the 2nd lens 12 is made of quartz and has negative power, and the 3rd lens 13 is made of fluorite and has positive power. Consequently, light in the ultraviolet range or far ultraviolet range can be transmitted through the objective, which is usable in the ultraviolet range and far ultraviolet range. Further, the 1st - 3rd lenses are isolated mutually across the specific air intervals, so the need for optical contact is eliminated and the objective lens can be obtained at low cost.</p> |
