Three major problems of large scale commercial technology cost standard of LED street lamp

LED (light emitting diode) applications can be said everywhere. As a kind of semiconductor light emitting material, compared with other luminescent materials, LED has the advantage of being green, efficient, reliable and durable. With the continuous reduction of the cost of high power LED, it is possible to gradually replace the traditional lamps. The application of LED light source in the road lighting has become a hot spot in the semiconductor lighting industry in recent years. What are the special requirements for the application of LED devices to the street lamps? What are the advantages of LED street lamp compared with the ordinary street lamp? What are the problems? How to solve? Industry experts from different sides are described.

National standard is a powerful means of popularization

Director Chinese Semiconductor Institute Li Jinmin

LED as the main street has the following advantages and characteristics: high luminous efficiency, light reflection loss is low, energy saving 70%; with the digital brightness control function, more power; without high pressure, high safety; with the software by the remote automatic control brightness; lighting accident, foggy and rainy weather and other special circumstances ultra high brightness and high color; easy installation and maintenance; module installation, no extra wiring; will not cause light pollution or waste; long life means not always need to be replaced, thereby reducing the potential traffic disruption, reduced pay maintenance costs. It was calculated that the use of LED street lamps in addition to the cost of a single lamp and the initial installation cost is higher than the high pressure sodium lamp, the cost of laying, power consumption and life expectancy are much better than high pressure sodium lamp.

The main technical problems of LED lamp: design output power and luminous flux, two optical design, thermal design and | power regulator system. The improvement of output power and luminous flux also needs to be further improved from the basic level of high power white LED epitaxy, chip technology and so on. In the two optical design, the radiation of the LED is Lambertian type, side jet type, bat airfoil and spotlight type. In the field of road lighting, according to the design experience of the Lambert type and the more suitable for the application of the bat, through the two optical design, making the LED light range, the curve of light in line with the needs of road lighting. Heat is one of the key problems to be solved in LED street, LED street lamp brightness due to high demand, a large amount of heat, and the use of harsh outdoor environment, if the heat is not good LED will directly lead to rapid aging, reduce the stability, in addition to the power LED itself with good heat dissipation, the lamp has the characteristics of outdoor use at night. The radiating surface located on the side of above is conducive to air natural convection. The power supply system of LED street lamp is also different from the traditional LED light source, low energy consumption and low voltage and low power output of solar cell components, low output voltage between the match is very appropriate, how to make an index tightly compressed together a group of LED safe and reliable work is a study of LED Street lamp.

Based on the above analysis on market prospect and technical problems of the LED lamp can be seen, the influence factors of its application for:

First, LED street high cost, is not conducive to the promotion and popularization. Although the initial solution to the problem of LED street lamp heat dissipation, but the high price and the weight of the lamp cap will hinder the popularity of LED street lamp.

Second, the reliability of LED lamp module still need to be strengthened, because of failure of driving circuit will cause the LED street lamp.

Third, either single point or multi-point source LED lamps have the problem of heat dissipation. A lamp with 250W high pressure sodium lamp, because the technology is more mature, the heat is well controlled, even 5000 hours of work, life is still small, the luminous efficiency can also reach more than 70%. With current technology, under the same conditions of high power LED street lamp, because the heat problem is not easy to solve, light is large, luminous efficiency will drop to 30%. If you want to increase the voltage and current methods to improve light efficiency, it is easy to cause the phenomenon of LED chip damage.

Fourth LED street, range is short, so LED Street still need further study how to strengthen the work in the higher altitude. In addition, the development of national LED road lighting standards are also popular to promote LED street lamp is a very powerful means.

Heat dissipation and reliability is the main factor affecting the application

Deputy general manager of Jiangsu Wenrun photoelectric Co Ltd Chen Hesheng

LED light source have two kinds of ways, one is to use the traditional small power LED combination, generally up to hundreds of or even hundreds of stars, the complex power supply design. Another is the use of high-power tube as light source, the price is more expensive. Two methods are inevitably to the thermal design and reliability as the main design considerations, many applied to government demonstration project, the real market operation of the project is very few, this aspect of foreign application more, but its biggest drawback is still reliable, light lumens and prices, because many engineering LED poor quality, not very good to show the advantages of long service life. Also, consider the cost, from the angle of the market, LED as a light source, and the combination of whether the use of solar energy in the design, it needs to take a different route, and not as a single light source development can be done.

LED devices applied to street lights, special requirements on technology mainly is to combine LED light intensity and light angle to design, also due to multiple combinations of LED optical design to take into account the irradiation area, lighting needs to focus on the effectiveness of radiation.