Laser marking is the use of laser beams on a variety of different material surface marked permanent. The marking effect is through the evaporation of surface material to reveal the deep material, or through the light can cause chemical and physical changes in the surface material and "carved out" traces, or by burning some of the material to show the desired etching Graphics, text.
A typical metallic material is marked with lines that are ablated to depths of several microns or more (widths can range from a few microns to tens of microns). From the surface so that the color of the line and the reflective rate is different from the original, resulting in human visual acuity contrast effect. People can be sensitive to these lines (and lines formed by the shape code, numbers, patterns, trademarks, etc.).
For glass, the ablated lines have a "dull" effect. For plastic, due to photochemical reactions and ablation, visual contrast and clouding effect. If the surface of the material coated with a special colored material for marking processing , the colored material will be fixed (with the material at high-temperature ablation) on the line and make it color.