| 摘要 |
PURPOSE:To protect a human body from a hazard due to a leakage from a damaged fiber by detecting damage caused to an optical fiber quickly to shield an incident laser light. CONSTITUTION:A laser incident light 2 focused with a condenser 1 emitted from a light source is made incident on an incident end 4 of an optical fiber 3, reaching the emission end 5 thereof 5 passing through the fiber 3 and then, most thereof is emitted to an intended object outside the fiber 3 while a part thereof is flashed back and emitted at the incident end 4 thereof. But when any damaged part exists inside 12 the fiber 3, the incident light 2 is released as heat energy from the side wall of the fiber 3 at the damaged part 12, resulting in a noticeable reduction in the quantity of light flashed back. Then, the laser reflected light 9 is received 6 and the output signal 7 is compared 10 with a reference output signal 8; when the signal 7 is below the output of the signal 8, the incident light 2 is shielded with a shutter 11a. Thus, due to the leakage from the damaged fiber, hazard to a human body can be prevented. |
