A mirror is an object with smooth surface and the ability to reflect light. At first, the ancients used polished bronze as a mirror. There are two types of flat mirrors and curved mirrors. Flat mirrors are often used by people to tidy up their appearance. Curved mirrors can be divided into concave mirrors and convex mirrors. They are mainly used as makeup mirrors, furniture accessories, architectural decorative pieces, optical instrument parts, as well as solar ovens, reflectors for lamps and searchlights, reflective telescopes, automobile rear-view mirrors, etc.