The glass inside the projector is called glass+resin lens, or it may be all-glass lens, which has the characteristics of high hardness, strong wear resistance and long service life. Projector, also known as projector, is a kind of equipment that can project images or videos onto the screen. It can be connected with computers, VCD, DVD, BD, game consoles and DV through different interfaces to play corresponding video signals. Projectors are widely used in homes, offices, schools and entertainment places. According to different working methods, there are different types such as CRT, LCD, DLP and 3LCD. The light sources used in projectors include traditional high-intensity gas discharge light sources (such as ultra-high pressure mercury lamps, short-arc xenon lamps and metal halogen lamps) and new solid light sources represented by LED light sources and laser light sources.