Former Southeast University professor Yang Zhengming
On April 25th, 2009, Aladdin Lighting Network invited domestic authoritative experts to hold a rational call for the 2009 LED application product achievements and trends behind Shenzhen, to share high-level with LED lighting companies, designers and terminal owners. The wisdom of the results.
Former professor of Southeast University, Guangdong Xuelaite Optoelectronics Technology Co., Ltd., senior consultant and chief scientist Yang Zhengming made a theme report on "High Power White LED Road Lighting Discussion". (Click here to download the full text of Yang Zhengming's speech: High Power White LED Road Lighting Discussion (PPT))
Interpretation of LED illuminating process: carrier composite illuminating
Mr. Yang Zhengming interprets several concepts in the LED luminescence process, including: internal quantum efficiency and quantum extraction rate. At the same time, he gave an example of the quantum efficiency and light output estimation of white LEDs.
In the street lighting, high pressure sodium lamp and high power white LED
Mr. Yang Zhengming first introduced the advantages and disadvantages of high pressure sodium lamps as a source of road illumination. Then, Mr. Yang Zhengming introduced the reason for the rapid development of high-power white LEDs in road lighting: one LED is directional radiation, the light utilization rate is much higher than that of high-pressure sodium lamps; two entrepreneurs and experts claim that LED light efficiency is as high as 90~160lm /W; three LEDs have long life (50,000 to 100,000 hours), low maintenance cost for street lamps; four LEDs are the latest best light source, dark vision high pressure sodium lamps are good, is the best choice for road lighting; five government energy saving Tasks, directively established a number of model road lighting projects, and intend to actively promote. Sixty-nine cities and millions of semiconductor lighting applications introduced promotion and publicity played a big role, everyone wants to share a piece of cake.
However, Mr. Yang Zhengming believes that the conditions of LED road lighting are not yet mature, and should exert its strengths and cannot be touched. The reasons are as follows: 1. The performance of the LED itself is difficult to meet the requirements; 2. The optical system of the LED is not yet mature; 3. The reliability of the supporting control circuit of the LED is too low; 4. The cooling system of the LED is too expensive and the efficiency is not high; The cost of the entire LED lighting system is too high to be promoted; 6. There is no uniform standard, each product is different and has no interchangeability, and the maintenance is difficult and the cost is high. Therefore, these problems make it difficult to promote LEDs.
Then, Mr. Yang Zhengming believes that it is necessary to evaluate the white LEDs: 1. LED is a promising light source; 2. Monochromatic LEDs and low-power white LEDs have been used in display lighting, decorative lighting, and low-power local lighting. It shows its superiority and will play a stronger role, but many aspects still need to be improved. 3. Exaggerated publicity of high-power white LEDs should be cautious.
Views on LED road lighting
Mr. Yang Zhengming affirmed his views on LED road lighting: 1. There are too many models of LED road lighting, and the loss is too great to continue. 2, spend another 5-10 years, when its light effect really reaches 80lm / W or more, single-grain power 5-10W, the cost per lumen is reduced to 3 cents, maintenance-free basic one year, then you can road Lighting entered. 3, many entrepreneurs have been lamenting the blood. The money of these entrepreneurs has been cast, but there is no market. Anything without a market must not be done.
Finally, Mr. Yang Zhengming made a serious appeal: experts and professors, suspend your own call for not spending money, focus on the light efficiency and reliable improvement of road lighting systems, and reduce costs, and do something for LEDs. R&D work.
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