| 摘要 |
<p>PROBLEM TO BE SOLVED: To form through holes having less difference of opening diameters by increasing the optical-processing energy density by using the reflected light from the processing object generated in laser abrasion working. SOLUTION: Laser light is used as a light source. The laser light is projected on a material 111 to be processed, by using an optical system through a photo- mask. The material 111 is irradiated with coherent laser light 112 and Laser abrasion process is performed. At this time, a taper angle 113 is formed at the external part of the portion where the material to be processed, is irradiated with light, and a tip-narrowed through hole 120 is formed. At the part where the depth of the through hole 12 exceeds (h), its counter side face is irradiated with laser light 114, which is reflected at the processing surface of the material to be processed, and the laser-energy density is increased. Thus, the through hole 120 is processed to broaden toward ends.</p> |
