| 摘要 |
The lens system for an infra red camera has a light passage (16) between the entry iris (36) and an image plane (18), with a series of lenses (26,28,30,32,34) in groups. The first lens group (26,32) is of zinc sulfide (ZnS) and the second lens group (28,30,34) is of zinc selenide (ZnSe). |
