The Back Light Unit is the provider of the liquid crystal display (LCD) light source. The LCD itself does not emit light. The performance of the backlight module light source determines the visual sense of the display. With the improvement of the manufacturing technology of liquid crystal displays, the trend of large size and low price, the backlight module is considering the market demand of lightweight, thin, low power consumption, high brightness and low cost, in order to maintain competitiveness in the future market, The development and design of new backlight modules and new production technologies for light guide plate molding are the future direction and important issues.