​Analysis on the current situation and problems of LED street lamp technology in China

    All countries actively promote the implementation of energy conservation and emission reduction projects, especially China"s LED street lamps are valued by LED street lamp manufacturers due to the huge business opportunities. Street lamp is an important part of urban lighting. Traditional street lamp often uses high-pressure sodium lamp. The low light efficiency of high-pressure sodium lamp results in a huge waste of energy. Therefore, the development of new efficient, energy-saving, long life, high color rendering index and environmental protection street lamp is of great significance to urban lighting energy conservation.

Today"s LED street light features:

    High power LED street lamp is different from conventional high-pressure sodium lamp. The light source of high-power LED street lamp is a high-efficiency white light diode (light emitting diode) powered by low-voltage DC and synthesized by GaN based power blue LED and yellow phosphor, LED) is an efficient solid-state light source based on semiconductor pn junction, which can emit light with weak electric energy. Under a certain positive bias voltage and injection current, the holes injected into the p region and the electrons injected into the N region diffuse to the active region and emit photons after radiation recombination, which directly converts the electric energy into light energy.
As the light source of street lamp, LED has many advantages compared with traditional street lamp.

    1. LED street lamp itself has light directivity, no light diffusion, to ensure light efficiency;

    2. LED street lamp has a unique secondary optical design, which irradiates the light of LED street lamp to the required lighting area, that is, the road surface, further improves the lighting efficiency and achieves the purpose of energy saving;
    3. At present, the light source efficiency of LED has reached 100lm / W, and there is still much room for development. The theoretical value can reach 250lm / W. however, the luminous efficiency of high-pressure sodium lamp increases with the increase of power, so the overall luminous efficiency of LED street lamp is stronger than that of high-pressure sodium lamp;
    4. The light color rendering of LED street lamp is higher than that of high-pressure sodium lamp, and the color rendering index of high-pressure sodium lamp is only about 23, while the color rendering index of LED street lamp can reach more than 75. Considering from the perspective of visual psychology, the light intensity of LED street lamp can be reduced by more than 20% on average compared with that of high-pressure sodium lamp (refer to the British road lighting standard); moreover, at the intermediate visual level, the human eye is in a high color temperature environment Compared with low color temperature environment, it is easier to distinguish things and avoid some dangerous states;
    5. LED street lamp has a small light attenuation, less than 3% in one year, and still meets the requirements of road use illumination after 10 years of use. Therefore, the design of LED street lamp in use power can be lower than that of high-pressure sodium lamp;
    6. LED street light can be automatically dimming, which can meet the lighting requirements in different periods, reduce the power as much as possible, and save power;
    7. LED is a low-voltage DC device. The voltage driving a single LED is a safe voltage, so it is a safer power supply than using high-voltage power supply, especially suitable for public places. The characteristics of DC make led especially suitable for combination with solar energy and wind power;
    8. Each unit of LED crystal has a very small volume, so it can be prepared into various shapes of devices, and it is suitable for the environment that is easy to change and shake;
    9. Long service life: the theoretical service life can be more than 50000 hours;
    10. LED can switch frequently without worrying about its damage;
    11. Simple installation: directly install the LED street lamp holder on the lamp pole to replace the original sodium lamp holder