| 摘要 |
PURPOSE:To irradiate a laser beam with an even spot diameter and over a wide range, by adding a laser beam viewfield stop-down mechanism consisting of a aperture and an optical element to a scan optical system of a laser scanner. CONSTITUTION:The laser beam radiated from a laser device 1 enters a beam expander 3 via a reflector 2 to be magnified and reaches a reflector 5 via a reflector 4. The beam passed through these reflectors reaches an objective lens 7 via a reflector 6 which limits the beam diameter with a slit 10 and is magnified by a concave lens 11. In this case, a reduced image of the slit 10 is formed by the lens 11, and an image is formed on the surface 12 of a workpiece by an objective lens 7 which uses the above-mentioned reduced image as a light source. In this case, the distance is constant between the slit 10 and the lens 7 if X and Y tables 8 and 9 move. Therefore both a slit image 10' and the lens 7 have no change. |
