Glass marking is a proven application for CO2 lasers and mirrored glass is no exception. The silver surface is ablated and the underlying glass substrate is fractured in a controlled manner, as in a normal glass mark. With this process, text and bar codes marked on the mirror's back-side are easily visible from the front.
This sheet of mirror glass was marked with an ECC200 Data Matrix code using a Synrad Firestar v40 laser, FH Series marking head and WinMark Pro laser marking software. The marking head was equipped with a 125 mm focusing lens that provides a 180-micron (0.007") spot size and a 3 mm (0.118") depth of focus over the extents of the mark field.
Cycle time to mark the 15-character code was 1.09 seconds and the resulting mark was read on both glass and silvered sides using scanners from Microscan (Quadrus EZ) and RVSI (CM4000 vision system).