LED Streetlights Has a Significant Impact on LED Industries

Published:2011/4/20 2:13:00 Author:LiuQiaoyan From:SeekIC

Cross-strait development of LED streetlights is booming as Mainland China and Taiwan all initiated LED streetlight demonstration projects which spur the growth momentum of LED industry effectively.

The progress is so obvious that in 2008 the luminous efficiency of LED lamps was 45 Lm/W and just one year later the number became 80 Lm/W, almost doubled. Whether the quality of the 80 Lm/W LED will pass the criteria that announced at the end of 2008 or not can not change the fact that the Research and Development sources will increase and the luminous efficacy of LED will improve. LED streetlight seems to replace high-pressure sodium lamps in existence soon.

The existing thermal discharge of LED streetlights can be divided into three types, that are heat-pipe, pin fin heat sink, and aluminum alloy heat sink. Products with high wattage adopt either heat-pipe or pin fin heat sink for heat dissipation. Most of the aluminum alloy type have heat sink that is exposed outside, this design is low cost specially in module development. As a matter of fact, weight is an important factor in the research and development of high-wattage products since there are certain limitations to the pressure the light poles can withstand in the public regulations.

Besides heat sink, another vital element in LED streetlights is the power supply. At present the most popular LED products are driven by direct current, so manufacturers should find ways to customize power supply for each type of LED street and adjust the drive LED drive circuit to meet the requirement of each country’s product safety standards. According to practical experience, most of the breakdown of LED streetlights are because of the power supply problem. The stability of power supply will have impact on the luminous quality of LED streetlights directly.

A fatal weakness of LED streetlight is the optical design capability. Good optical property in the lighting fixture allows LED streetlights to be illuminated on the road surface uniformly. According to the NS15233 criteria in Taiwan, the glare for streetlights should be less than 30 at a 80-degree angle, and 10 at 90-degree angle. What’s more, there are specific brightness specifications at an angle of 65 to 95 degrees. A streetlight with good optical design can improve its lighting quality effectively. When choosing the products, if they are equal in both quality and reliability, what matters is the lighting performance.

The development of LED industry can not dispense with government’s support. Early in 2008, Taiwan has announced its national LED streetlight criteria officially. Mainland China’s streetlight standards will be established by each provinces respectively, and product performance tests also vary accordingly. For westerners, like Europe and the United States, these standards also specify criteria for the lighting angle, quality, light decay, etc. The related integrated circuit is LM2002AT.

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