| 摘要 |
<p>PROBLEM TO BE SOLVED: To make it possible to control the height of the projecting parts of laser marks to values of a specific range by irradiating a substantially flat nonmagnetic brittle substrate with a laser beam and forming plural sets of the laser marks having the projecting parts in at least part thereof on the surface of the substrate, then subjecting the parts inclusive of the laser marks to a heat treatment. SOLUTION: The laser marks 3 having the projecting parts in at least part are formed by irradiation with the laser on the part on the side to be formed with the magnetic layer 2 of the nonmagnetic brittle substrate 1 consisting of a glass material, glass ceramic material, ceramic material, etc. The magnetic layer 2 is a ferromagnetic alloy of a Co alloy system having, for example, 50 to 500A thickness and is formed by a sputtering method, etc. After the laser marks 3 are formed, the parts of the substrate 1 inclusive of the laser marks are heat treated. The substrate is heated up, is held at the temp. and is then lowered more gently as compared with the cooling temp. arising in a laser process, by which the height of the laser marks 3 is controlled to 10 to 500A.</p> |
