| 摘要 |
PROBLEM TO BE SOLVED: To prevent fogging and deterioration of objective lenses by preventing intrusion of steam even if autoclave sterilization is repeatedly performed. SOLUTION: The front end cover frame 14 of a front-end hermetic optical cover member 38 and the frame 20 of a rear-end hermetic optical cover member 39 are hermetically joined, from a longitudinal direction, to an insulating frame 17 which supports a lens frame 16 holding a group of objective lens 15, and thereby the group of objective lenses 15 is sealed. Since the group of objective lenses 15 is sealed, intrusion of moisture is prevented even if autoclave sterilization is repeatedly performed, to thereby prevent fogging and deterioration. |
