| 摘要 |
PURPOSE:To measure the focal length of a work lens by off machine by providing the work lens for laser and photodetecting means on the optical path of the visible laser light shaped in a cylindrical light and reading a focus position based on the annular pattern of a transmitting light. CONSTITUTION:The visible laser light 2 by an He-Ne laser device 1 is shaped by the optical mechanism 8 consisting of mirrors 3, 4 and a lens 6 in a cylindrical light 7. The cylindrical light 7 is then made incident on the work lens 9 for laser held on a work lens holder 10 to project a transmitting light 12 on the photodetecting face 14 of a photodetecting means 13. At this time the annular pattern of the transmitting light 12 on the photodetecting face 14 is observed at both positions A, C in the vertical direction of a focus position B to read the distance DB of the focus position B based on the distances DA, DC from the reference position of each position A, C. The difference in the visible light and the laser light for working is corrected further at the read focus position of the lens 9. The focal length of the work lens can thus be adjusted in an off machine state for a laser machine. |
