Laser engraving is a process of surface treatment by optical principles , similar to pad printing , both printed or patterned on the product. Most used in cell phones and electronic dictionaries on the keystroke. The high intensity focused laser beam emitted by the laser is used at the focal point, which causes the material to be oxidized and thus processed. The light energy of the laser beam can cause the chemical and physical changes of the surface layer substance to be carved out , or the part of the substance can be burnt out by the light , so that the pattern and the character of the required etching are displayed. Materials used for laser engraving include stone, bamboo and wood products, glass, metal plate, leather, plastic, crystal, paper, double color boards, alumina, epoxy resin, polyester resin and so on.