LED street lights in the open after the use of a long period of time, and gradually make the internal temperature of the LED street light continue to rise, if not timely will produce heat out, will have a great impact on the life of street lamps, serious Will make the LED street lights and street lamp lamp damage.
LED street light source As with traditional light sources, semiconductor light-emitting diodes (LEDs) also generate heat during operation, depending on the overall luminous efficiency. Under the action of external energy, electron and hole radiation recombination occurs electroluminescence, in the PN junction near the radiation from the chip itself through the semiconductor medium and packaging media to reach the outside (air). Integrated current injection efficiency, radiation quantum efficiency, chip external light extraction efficiency, etc., and ultimately only about 30-40% of the input power into light energy, the remaining 60-70% of the energy mainly non-radiation composite lattice vibration Form of heat transfer.
LED street lights work is stable, good quality, and the lamp itself is essential to heat, the market's high-brightness LED street lights cooling, often using natural heat, the effect is not ideal.
The main structure of the LED street light source with LED street light source is composed of LED, heat dissipation structure, driver, lens and so on. So heat is also an important part, if the LED can not be a good heat, its life will be affected. Thermal management is a major problem in high brightness LED applications. Since the p-type doping of the group III nitride is limited by the solubility of the Mg acceptor and the higher starting energies of the holes, the heat is particularly susceptible to the p-type region, which must pass through the entire structure to dissipate on the heat sink; LED devices are mainly heat conduction and thermal convection; substrate material very low thermal conductivity led to increased device thermal resistance, resulting in a serious self-heating effect on the device performance and reliability of a devastating impact. The effect of heat on high brightness LEDs. The heat concentration is concentrated in the chip with very small size, the temperature of the chip is increased, the non-uniform distribution of the thermal stress is caused, the efficiency of the chip and the lasing efficiency of the lasers decrease. When the temperature exceeds a certain value, the device failure rate increases exponentially.
According to a study data statistics: component temperature for each rise 2 ℃, reliability decreased by 10%. When a number of LED string, parallel arrangement of the composition of the LED street lighting system, the heat elimination problem is the industry has been concerned about the problem. Solve the problem of heat management has become the primary factor in high-brightness LED applications.