Street lamps in cities not only illuminate roads, but also bring a lot of light pollution and energy waste. According to the physicist's network, a group of researchers from Taiwan and Mexico, China, have developed a new type of lighting system that ensures that street lights only illuminate where light needs light, without producing unnecessary light, by using the LED. The related research is published in optical journal, , sponsored by the Optical Society of America. 2 details are on roads that are illuminated by ordinary street lamps, especially on narrow roads. What we often see is that the bright and dark areas of the road are zigzag. This traditional lighting way is not only inefficient, but also causes serious light pollution. It is found that over 1/5 of the power of traditional street lamps is wasted by horizontal and upward light. "One of the unique functions of this new LED system is that it can adapt to the layout of street lights in different streets and provide efficient lighting for various streets and roads," said Professor Sun Qingcheng, the Department of photoelectricity and engineering at the National Central University, China. This new street lamp system consists of three parts. The first part contains a string of light-emitting diodes, each equipped with a device called the TIR, which works to gather light, accurately control the direction of the beam, and make the light beam out in parallel without crossing each other. These lenses are installed in a reflector cavity that is used to recover light and to ensure that they are more used to illuminate the target, which is the second part of the system.