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The Outlook: LED Street Lamps to Replace Conventional Ones in Future︱ LED Outdoor lighting II


2009-12-16 Optical Semiconductors editor

Generally speaking, those who believe that there is no possibility of a large scale replacement with LED street lamps mainly take two factors into account: the quality and cost of LED street lamps. The quality problem exists in all aspects: luminous flux, luminous efficacy, luminous decay, thermal dissipation, color temperature, luminance distribution, stability, homogeneity, power supply and lifespan of other components. On the other hand, the cost of street lamps is several even dozens times higher than conventional street lamps. The LED street lamp, however, has its own strength in energy-saving, theoretically long service life and environmental-friendliness. As green environmental protection becomes a global theme today, it has won extensive support from governments and industries.

 
Breaking the Bottleneck is Only a Matter of Time
Governments around the world have increased funding for LED industry input and aids, take China for example, in the first half of the year, the investment into the LED industry amounts to 20 billion RMB. A high input into LED research and production from governments and enterprises will effectively enhance the quality of LED products and reduce the cost. In December 2009, Cree’s white LED achieved 186lm/W lab efficacy. With continuous enhancement of LED chip efficiency, the energy saving advantage of LED products will become more remarkable. In the future, as new materials and technologies are adopted in the LED street lamp, its overall quality problems including luminous efficacy, lumen depreciation, heat dissipation, color temperature, luminance distribution, homogeneity, stability and power supply will have better solutions. Technological advancements and mass production will not only effectively lower the cost but also gradually resolve the existing bottlenecks of the LED street lamp.
 
Customization Becomes Possible
Customization is to produce the best and most suitable products to meet different needs. Since street lamps are used in different environments, needs vary widely depending on time, place and weather. When the LED street lamp industry reaches the mature stage, manufacturers are fully capable of providing LED street lamps according to various needs, and even further, to offer the best solution based on information provided by the customer. Major countries and districts, including China, America, Japan, Taiwan, and Korea are developing industry standards for LED street lamps, whose implementation will give better benchmarks and guarantees for LED street lamp development and production.
 
New Research Topics on Street Lamp Needs are Proposed
A systematic research needs to be conducted to determine the most suitable street light in different environments. Due to the specialty of the light source, theoretically, LED street lamp can present any color. There is still no authoritative theory about the most suitable color and brightness under different road conditions. It is reported that the road looked darker than before, after LED street lamps had been installed in Foshan City. It is because LED street lamps perform better color reduction that the black road surface looks darker. Another report says that 99% of car owners found LED street lamps fixed on some roads better than high pressure sodium lamps. As sharp performance discrepancies exist in various road conditions, the government or industry can organize experts to conduct a systematic research on the needs of light in different road conditions (including altitude, area, climate, time, and user) in order to discover best solutions. For instance, different surroundings require the light color to be white, yellow, even red, green or blue; other requirements include luminous flux or luminance distribution and so on. When those research results form a comprehensive database, LED street lamp makers will be able to offer street lamps meeting specific needs. It is even possible for an LED street lamp with automatic adjustment system to give off different colors according to varying needs.
 
Intelligent Control System is Another Advantage over Traditional Street Lamps
Unlike conventional light sources, in terms of some features, LED is an electronic component which can be intelligent-controlled via IC. Current LED intelligent control system can perform stepless control of LED brightness based on road conditions so as to extend the service life of the LED street lamp and save energy. For example, the LED street lamp intelligent control system invented by Institute of Computing Technology, Chinese Academy of Science, is composed of following intelligent control devices: motion image sensor components to detect moving objects on the road and transmit the result to the microprocessor, which receives the detection result, generate control orders of programmed lighting time and transmit them to the switch control, which keeps the specified LED lamp on for programmed time length. The intelligent control devices also include communication components like a sender and a receiver. Moreover, the motion image sensor components can detect the moving direction of a moving object, which in turn is sent to the microprocessor to light up the LED street lamp right in the direction in advance.
 
In future, the ultimate development of the intelligent control system may realize not only the automatic adaption of the brightness, color and angle of the LED street lamp based on different environments, but also the real-time monitoring of the lamp use in order to achieve optimization under intelligent control.  
 
Conventional Street Lamps will be Replaced with LED ones
The LED street lamp has many advantages, in particular, it offers unmatched energy-saving and environmental friendliness compared to traditional street lamps. When its technology becomes mature, its strength in eco-friendliness will be more salient. Nowadays, the LED industry is one of the most promising industries, where the speed of technological advancement has gone beyond imagination and industry standards are being established. When the LED street lamp has a stable quality, long lifetime, and intelligent control, its cost will then lower to an acceptable range, and LED street lamps will ultimately replace the conventional ones.

 

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