LASER MARKING IN DYE-POLYMER SYSTEMS

Light‐induced marking in dye–polymer systems based on dye diffusion was investigated. It was demonstrated that when a dye film coated on an appropriate polymer substrate is exposed to a laser beam, marked areas are obtained. In the exposed areas the dye melts and diffuses into the substrate and also flows laterally. The dye, when diffused into the polymer, shows altered spectral characteristics, and significant changes of optical densities can occur in the marked areas. A direct optical marking process based on these phenomena is described. Good spatial resolution and adequate marking sensitivities were demonstrated as submicron marks and energy density requirements below 100 mJ/cm2 were obtained. Copyright © 1979 John Wiley & Sons, Inc.