206 On the laser marking to aluminum film in the media.

Abstract

In order to attempt the direct laser marking on CD-ROM disk for identification, laser processing was carried out against a thin Al film in the transparent medium of the CD. A disk laser (532 nm wavelength of second harmonic, max 3W) was used as a heat source for the processing. Surface conditions of laser marking area were observed using SEM and a optical microscope, and reflectance of the marking areas was measured by a photo diode installed in the optical microscope. The laser-marking size less than 1μm was obtained using NA=0.8 objective lens system.