Reflector efficiency of the device. In addition, the light efficiency detection of LED already includes the efficiency of its own reflector. Road lighting fixtures using LED should make full use of the directional emission characteristics of LED as much as possible, so that each LED in the road lighting fixture directly projects light into each area of the illuminated road surface, and then use the auxiliary light distribution of the lamp reflector to achieve a very reasonable comprehensive light distribution of road lighting fixtures. It should be said that road lighting fixtures must truly meet the illumination and uniformity requirements of CJJ45-2006, CIE31, and CIE115 standards, and the lighting fixtures should include three light distribution functions in order to achieve better results., LED with a reflector and a reasonable beam output angle itself has good primary light distribution function. Within the lighting fixture, the installation position and direction of emission of each LED can be designed according to the height and width of the road lighting fixture to achieve good secondary light distribution function. The reflector in such lamps is only used as an auxiliary third light distribution method to ensure better uniformity of road illumination.

In the actual design of road lighting fixtures, it is possible to fix each LED to the fixture with a spherical universal joint while basically setting the direction of each LED. When the fixture is used at different heights and widths, the spherical universal joint can be adjusted to achieve satisfactory results in the direction of each LED's illumination. When determining the power and beam output angle of each LED, the power that each LED should have at the basic selected beam output angle can be calculated based on E (lx)=I (cd)/D (m) 2 (inverse law of light intensity and illuminance distance square). The expected light output of each LED can be achieved by adjusting the power of each LED and the LED driver circuit to output different power to each LED. These adjustment methods are unique to road lighting fixtures that use LED light sources. By fully utilizing these characteristics, it is possible to reduce the lighting power density while meeting the illumination and uniformity of the road surface, achieving the goal of energy conservation.

2. The power system of LED street lights is also different from traditional light sources. The constant current driving power supply required by LEDs is a major cornerstone to ensure their normal operation. Simple switching power supply solutions often cause damage to LED devices. How to ensure the safety of a tightly compressed set of LEDs is also an indicator for evaluating LED street lights. The requirement of LED driving circuit is to ensure the constant current output characteristic, because the junction voltage relative variation area is very small when LED is working forward, ensuring the constant driving current of LED basically ensures the constant output power of LED. For the current situation of unstable power supply voltage in China, it is necessary for the driving circuit of road lighting LED to have a constant current output characteristic, which can ensure constant light output and prevent LED from operating at excessive power.

If you want the LED driver circuit to exhibit constant current characteristics, looking inward from the output end of the driver circuit, its output internal impedance must be high. During operation, the load current also passes through the internal impedance of this output. If the driving circuit is composed of a step-down, rectified and filtered DC constant current source circuit or a general switching power supply and resistance circuit, it will inevitably consume a lot of active power. Therefore, these two types of driving circuits cannot be high in efficiency while basically meeting the constant current output. The correct design scheme is to use an active electronic switch circuit or use high-frequency current to drive LEDs. Using these two schemes can ensure that the driving circuit maintains good constant current output characteristics while still having high conversion efficiency