| 摘要 |
PURPOSE:To subject the circumferential part of a material to be treated to a uniform and defectless surface treatment by forming laser light to a luminous flux of an annular section having a prescribed axial line by an optical system and moving the same along the common axial line of the optical system and the circumferential part of the material to be treated. CONSTITUTION:The laser light 2 is made incident on a circular conical mirror 1 from above to below. The laser light 2 is reflected by a reflection surface 1a and is emitted in the annular sectional shape having the axial line 2a. The emitted light is focused onto the circumference centering at the axial center of an inside peripheral surface. The focused light is positioned to the circumferential part 4a at the top end edge of the surface 4 and the laser light 2 is irradiated into the circumference in the circumferential part 4a. The surface of the circumferential part 4a is subjected to the surface treatment such as build-up welding and alloying treatment by such laser light 2. The radius of the circumference of the laser light to be irradiated to the material 5 to be treated increases if the circular conical mirror 1 is moved upward along the axial center of the surface 4, i.e., the axial center of the circumferential part 4a. The plane between the circumferential parts 4a and 4b is thus beautifully surface-treated. |
