| 摘要 |
PURPOSE:To prevent the disturbance of measurement by external noise light by using a light beam subjected to higher harmonic modulation as a signal light beam to be used for measurement and removing the noise components by a filter on the electrical output side of a photodetecting element. CONSTITUTION:This posture detector is disposed with plural pieces of measuring systems around the central axis of a laser beam gun and generates spots ai(i=1-4) on the surface J of a work piece. The irregularly reflected light from the spots ai form the image Aio of the spots ai on Si when the posture of a beam gun has a stipulated value by the photodetecting element. The components corresponding to the noise light are removed by using the bypass filter on the electrical output side of the photodetecting element and the disturbance of the measurement by the noise light is prevented if the signal light beam used for the measurement is previously modulated by a high frequency of about several hundreds kHz. |
