Broadly speaking, high-power LED means that the power of a single LED light source is greater than 0.35W (including 0.35W). Basically, we focus on 1W.
Although many companies in our country develop and produce LED urban lighting street lights, many of them use low-power LED arrays as luminous bodies. The heat dissipation problem is solved. The number of LEDs used is large. Low-power LEDs have strong luminous decay and high installation costs; urban lighting LEDs The use of high-power LEDs in street lamps is a development trend. The few street lamp products that use high-power LEDs as luminous bodies do not solve the problem of heat dissipation of LEDs when the power reaches a certain amount; LED astigmatism and concentration control problems; street lamps are on the road The illuminance range, type, and illuminance balance of the illuminated surface; photoelectric conversion efficiency is too low, there are only a few lumens per watt and other problems. Therefore, the product performance is still not satisfactory; the price of high-performance products remains high and it is difficult to popularize. Heat dissipation and reliability are the main factors affecting LED applications
There are two approaches to LED light sources. One is to use traditional low-power LEDs as a combination, usually as many as hundreds or even hundreds, and the power supply design is complicated. The other is to use a high-power tube as a light source, which is more expensive. Both methods inevitably take heat dissipation design and working reliability as the main design considerations. Domestically, they are mostly used in government demonstration projects, and there are few projects that are truly market-oriented. There are many examples of applications in this area abroad, but they The biggest shortcomings are still reliability, luminous lumens and price. Many projects do not show the advantages of long life due to the poor quality of LEDs. In addition, from the perspective of cost and market, whether LED is used as a lighting source in combination with solar energy requires a different route in design, and it cannot be developed as a light source alone.
When LED device products are applied to street lamps, the special technical requirements are mainly to combine the LED light intensity and light-emitting angle to design. In addition, due to the combination of multiple LEDs, the light output design must take into account the irradiation area, and the lighting needs to focus on the effective heat dissipation.
The comparative advantages of LED street lights and ordinary street lights: energy saving, environmental protection, easy to adapt to low voltage, and can also be directly matched with solar systems, without additional inverter and conversion processes, and can achieve maximum energy utilization.
Disadvantages: the illumination angle is small and uneven, the color rendering index is low, and the optical and heat dissipation design is complicated.
Technical shortcomings: The luminous flux under current technology is not enough, the luminous efficiency is too low, and the quality is difficult to guarantee.
Solution: The application of LED products to street lights requires special design and special standards (using traditional light source test data to evaluate LED light sources is often not objective).
LEDs used in street lights have inherent advantages and disadvantages. The advantages are: first, as a point light source, if the design is reasonable, LED can directly solve the problem of secondary light extraction and light loss that traditional spherical light sources must rely on light emission to solve; second, the uniform light irradiation surface Controllable, theoretically it can be completely uniform in the target area, which can also avoid the waste of light in the phenomenon of "lighting under the lamp" of traditional light sources; third, the color temperature is optional, so that it can also be improved in different applications An important way of efficiency and cost reduction; fourth, there is still a lot of room for technological progress.
Disadvantages (factors affecting the promotion and application of street lamps): The current price is too high and the luminous flux is low. The current price of LED light sources with the same illuminance design is about 4 times that of traditional light sources (but in street light products, the light source part does not account for the total cost , So the cost increase ratio in engineering installation will not be too high, and the application space is still relatively large), which is unbearable in civilian use. The current design and manufacturing standards are rather chaotic, and the country has not issued hard standards. The LED street lights produced by some manufacturers have a high damage rate, which affects the public's understanding of the LED life advantage.
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