| 摘要 |
PURPOSE:To improve abnormality detecting capability, by providing photosensors to the laser beam input side of a laser beam condensing means and between a laser oscillator and laser transmitting means and detecting a light transmitting condition in accordance with mutual comparison of their detecting values. CONSTITUTION:Laser beam coming out from a laser oscillator 1 is converged by means of a light condensing device 4 after passing through a lens 2 and transmission system 3 and irradiated upon a steel sheet 7. In this case, the 1st photosensor 10 is installed to the laser input side of the condensing device 4 and a mirror and the 2nd photosensor 9 are provided on the input side of the transmission system 3, so as to detect part of the laser beam. Reflecting beam detected by the sensor 10 is amplified by an amplifier 12 and the incident beam of the sensor 9 is amplified by another amplifier 11, and then, both are compared with each other. By making this comparison, abnormality detection of each element of the laser beam transmitting system can accurately be carried out. Therefore, the abnormality detecting capability is improved. |
