| 摘要 |
<p>PROBLEM TO BE SOLVED: To prevent an optical fiber from being damaged by a reflected light beam from an object to be irradiated, by means of a simple structure. SOLUTION: Near the tip end of an optical fiber 14, a cap 50 having a nearly gimlet-shaped reflection area 51 is arranged in a state of non-contact with the optical fiber 14, thereby a reflected light beam is reflected in a direction different from that of the incident light beam.</p> |
