| 摘要 |
PROBLEM TO BE SOLVED: To prevent coating from being burnt with a laser beam by storing with and a condensing lens a glass plate for changing the focal distance of the condensing lens in a housing and thereby eliminating accumulation of dust on the coating of the glass plate. SOLUTION: A laser beam 2 is reflected by a reflecting mirror 51, converged by a condensing lens 52 and passed through a glass plate 53. The glass plate 53 acts to extend the focal distance of the condensing lens 52. The laser beam 2 goes out of the housing 5 through a moving lens 54 and an outgoing beam glass 55, and is emitted to the surface of a work 4. Plural glass plates 53 are fixed on a circular supporting plate 531. Various glass plates 53 may be used by turning the supporting plate 531. Marking is possible quickly without lowering a marking precision to a work 4 with a different marking height. |
