| 摘要 |
<p>PROBLEM TO BE SOLVED: To make a marking of good visibility on an optical material, without generating a crack by using a laser oscillator which outputs a pulse laser beam having an infrared wave length and a width of given range. The beam is deflected by a scan optical system and irradiates a processing area of the optical material. SOLUTION: The pulse laser beam emitted from the laser oscillator 11 has an infrared wave length and a width of 30-100μsec and, is to be transmitted to a polygon mirror 16 via a beam warping optical system 12, a mirror 13 and a total reflection mirror 15. The polygon mirror 16 deflects the pulse laser beam in the linear direction in a processing area of the glass substrate 18 to make a dotted scanning in one axial direction. A concaved portion is thus formed on the surface of the glass substrate 18 by an abrasion and a marking of desired letters or symbols and the like are performed. When the pulse width is shorter than the low limit, a dot size gets smaller and the visibility gets worse. On the other hand, if it exceeds the upper limit, a crack occurs.</p> |
