1.The main function：
LED garden light development into the 21st century, has been widely used in urban slow lane, narrow lane, residential areas, scenic spots, parks, squares, private garden, garden corridor and other public places used for road lighting one or two volumes, the way of improving the security of people travel at night to increase people's outdoor activities, improve the life and property safety. It can also change people's mood, improve people's mood, and can change people's concept, creating a palette of light and dark night. During the day, courtyard lights can adorn the urban landscape; Night, courtyard lamps and lanterns can provide the necessary lighting and living convenience, increase the sense of security of residents, and highlight the city highlights, interpretation of beautiful style, so that in use until now, has developed into a mature industrial chain.
（1）. An LED is a semiconductor diode that has a very long life. When the flux is reduced to 80%, the lifetime reaches 50,000 hours. The metal
The service life of halide lamp is 6000~12000 hours. The service life of high pressure sodium lamp is 12000 hours.
（2）. The basic structure of LED is a piece of electroluminescent semiconductor material, which is placed on a shelf with lead wires and sealed with epoxy resin around it to protect the inner core wires. Therefore, LED has good seismic performance.
（3）. The light color of white LED is better than that of high pressure sodium lamp. At the intermediate visual level, it is easier for the human eye to distinguish things in a high colour temperature environment than in a low one. The color rendering performance of white LED is much better than that of high pressure sodium lamp. The color rendering index of high pressure sodium lamp is only 20 right and left, while white LED can reach 65~80. its
（4）. LED can achieve perfect dimming function. Due to the large working range of LED, its light output is proportional to the working current, so it can reduce the current method to dimming. In addition, due to the frequent switching of LED does not cause much damage to it, the dimming of LED can also be obtained by adjusting pulse width. By adjusting the duty ratio of voltage and working frequency, the luminous intensity of LED can be effectively adjusted.
（5）. In the optical system of the lamp, the LED light source has the smallest luminous flux loss. Different from traditional light source, LED is the light source of half space. High pressure sodium lamp or metal halide lamp is the light source of full-space luminescence. It needs to change the outward light of half space 180° to the other half space. When we rely on the reflector to complete, reflector absorption of light and the source of its own light blocking is inevitable. But using LED as light source, there will be no such loss, and the utilization rate of light is higher than traditional light source. Finally, LED light sources contain no harmful metal mercury, unlike high-pressure sodium or metal halide lamps
Hazardous to the environment when scrapped.
Although the LED courtyard lamp is still three times more expensive than the high-pressure sodium lamp, under the factors of comprehensive power consumption and maintenance cost, after two years of use, the total cost of LED courtyard lamp is almost equal to the high-pressure sodium lamp. Therefore, in the long run, the use cost of LED garden lights will be better than high pressure sodium lamps. Compared with the 6-meter LED courtyard lamp and the high-pressure sodium lamp, the power consumption of the high-pressure sodium lamp is about 250 watts, and the LED only needs 60 watts. In the service life, the high-pressure sodium lamp averages about 4,000 hours, but the LED can be as long as 50,000 hours. As the price of LED courtyard lights continues to drop, its competitive advantage will become more and more obvious.
4.The efficient use of：
LED has high luminous efficiency. The light efficiency of procureable LED has reached 100lm/W, which is much higher than that of energy-saving lamp, metal halide lamp and infinite lamp, and 10% higher than the high pressure sodium lamp commonly used in street lighting. Therefore, LED has become one of the most efficient light sources. It is only a matter of time before leds replace incandescent, fluorescent, metal halide and high pressure sodium light sources.