The first generation of Witness Plates used a black marking that allowed the PDM to recognize the plate. However, this marking had a drawback: with use, the material degraded, making it difficult for the PDM to recognize the Witness Plate over time. In the next version, the marking was replaced with laser engraving, which is permanent and does not degrade. However, the engraving created sharp edges that, with unsuitable cleaning methods, could generate particles—undesirable in cleanroom environments.

Our latest WP solves this problem! By embedding the engraving within the glass rather than on the surface, the surface remains completely smooth. Our customers now benefit from a WP that never degrades and cannot generate particles, no matter the cleaning method. The new Witness Plates will soon be available!