| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a method of positioning the focus in a laser beam machining device by which the focus is accurately positioned without using special equipment, by easy operation and without personal error even when the position of a lens is difficult to confirm and the focal distance can not be measured. <P>SOLUTION: A recessed part 21 is formed by radiating a laser light 21 through an objective lens 23 from a laser light source to a laser absorber 13 of preferably≥10 mm in thickness placed on a working surface plate 11. When laser output and pulse width are in a proportional relationship with the depth of the recessed part 25, by preliminarily preparing the calibration curve of the depth of the recessed part 25 and focus displacement and subtracting the thickness (a) of the laser absorber from the distance T between the lens 23 and the laser absorber 13, at which the maximum depth of the recessed part 21 is obtained, the focus is made to coincide with the surface of the working surface plate. The laser absorber is an acrylic plate and the laser light source is carbon dioxide gas laser. <P>COPYRIGHT: (C)2007,JPO&INPIT</p> |
