With the global energy shortage and environmental pollu […]
With the global energy shortage and environmental pollution, LED has a broad application space for its energy-saving and environmental protection characteristics. The application of LED lighting products in the field of lighting is attracting the attention of the world. In general, whether the LED lamp works stably, the quality is good or bad, and the heat dissipation of the lamp body itself is very important. At present, the heat dissipation of the high-brightness LED lamp on the market often uses natural heat dissipation, and the effect is not ideal.
LED night light manufacturers remind: LED light source LED light fixture, composed of LED, heat dissipation structure, driver, lens, so heat is also an important part, if the LED can not heat well, its life will be affected.
1, thermal management is the main 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 energy of the hole, heat is particularly easily generated in the p-type region, and this heat must be dissipated through the entire structure on the heat sink; The heat dissipation path of LED devices is mainly heat conduction and heat convection; the extremely low thermal conductivity of Sapphire substrate materials leads to an increase in thermal resistance of the device, resulting in a serious self-heating effect, which has a devastating effect on the performance and reliability of the device.
2, the impact of heat on high-brightness LED
LED night light: The heat is concentrated in the chip with small size, the temperature of the chip rises, causing the non-uniform distribution of thermal stress, the luminous efficiency of the chip and the lasing efficiency of the fluorescent powder; when the temperature exceeds a certain value, the device failure rate is The index law increases. Statistics show that for every 2 °C rise in component temperature, reliability is reduced by 10%. When multiple LEDs are densely arranged to form a white light illumination system, the heat dissipation problem is more serious. Addressing thermal management issues has become a prerequisite for high-brightness LED applications.
3, the relationship between chip size and heat dissipation
Energy-saving night light lamp manufacturer LED night light: The most direct way to improve the brightness of power LED is to increase the input power, and in order to prevent the saturation of the active layer, the size of the pn junction must be increased accordingly; increasing the input power will inevitably increase the junction temperature. High, which in turn reduces quantum efficiency. The increase in single-tube power depends on the ability of the device to derive heat from the pn junction, and to increase the size of the chip separately, while maintaining the current chip material, structure, packaging process, current density on the chip, and equivalent heat dissipation conditions. The temperature will continue to rise