Recently, LED street lighting business has become a new direction for street light manufactures in China. LED street lights are quite different from traditional street lights: point light sources, high power consumption; Narrow beam output. These require more sophisticated designs for LED street lamps. It is a systematic process. In order to designer LED street lamps with higher performances, designers should make a study of street lighting standards and photo-mixing principles for traditional street lights, taking full advantage of LED street lamps: point light sources, controllable beam angle and long life cold light sources.
Choosing suitable LED light sources is the key to the entire designs, since they will directly impact LEDs’ performances, costs and working lives. Some LED street light manufacturers use single LED moudle with a power consumption of 10W. In fact, this design is unreasonable and has many defects: harder in photo-mixing; more glares; more difficult in heat radiation, etc. Some manufacturers tried to use the combination of several LED modules (with 3W-5W for each). This design also has defects: insufficient lighting effect and heat radiation problems. Above all, high power (10W) LED is more reasonable. With current high power LED technology, 10W LED street lamps have better lighting effect.
There are two main colors in street lighting: yellow light and white light. Basically, high pressure sodium lamps (HPSL) emit yellow rays. HPSL is the mainstream street lighting technique in China, due to its energy-saving property and strong fog- penetrability. However, yellow light has its own defects: low CRI. Under sodium lights, objects will be coated by yellow lights, which is a distortion. White light is closed to natural light, having much better CRI compare with yellow light. Metal halide lamps were used in the early stage of white-ray LED street lighting industry. Metal halide lamps have better CRI, but also very weak fog- penetrability and short service lives. They did not wide spread at that then. Then LED manufacturers concentrated on a newborn lighting technique: LED, and joint into LED street lighting business one after another. The normally used color temperature of LED street lamps is around 3500K (cool white). LED street lamps have higher CRI, better lighting effect, better fog- penetrability, and can work for a long time. It is impossible to prevent LED street lamps to be the mainstream products in street lighting business. Soon, traditional street lamps will be replaced by them completely.