Currently, the majority of LED roadway lighting applications face with serious light attenuation. This problem can only be fundamentally solved through the improvement of LED cooling technology. According to recent statistics, China has the highest growth rate in LED roadway lighting applications. It is predict that this dominating will be continued in 2013 in the global market. In 2012, the Chinese Ministry of Science and Technology issued a LED-lighting-related project: “Ten thousand lights in ten cities”. Although this implementation is a economic model that create the market demand via central government policies, but the response is not as good as expected.
Lacking of unified LED standard is not the only reason for the huge gap between the market and policies, serious light attenuation of LED roadway lighting applications is another potential problem for this issue. The former unified standard will be possible programmed in the near future, while light attenuation problem still need to be solved via the improvement of cooling technology.
Temperature is the major element to accelerate the light attenuation. As a type of high-powered LED lighting applications, LED roadway lamps usually work in high temperatures. LED street lights have relatively high working temperatures than ordinary residential lamps. Thus LED manufacturers paid a large amount of energy and money on the development and design of heat dissipation substrates, sinks and other cooling models. After package, makers need to take painting process to keep cooling models away from climate erosion. Unexpectedly, the external protection seal back the heat generated by LED lamps, speeding up the light attenuation of them.
The heat generated by LED chips / LED light sources are a type of small ranged concentrated thermal energy. For high-powered LED roadway lighting applications, the high input power and the high interface temperature are also heat sources with lamp bodies. Working in high temperatures for a long time, if cooling models cannot effectively conduct all heat outwards, not only the service life and performances of LED lights will be affected, but also the light attenuation will be more serious. LED street lights are normally used outdoors, taken into account of the climate factor, most of manufacturers added anodized shell protections or spray paint on the surface of lamp bodies, which is definitely block the heat dissipation.