LED Reliability is Greatly Affected by Temperature
Time:2018-01-08
Views:198
LED Reliability is Greatly Affected by Temperature
The principle of illumination of the led display is the combination of electron and hole pairs in the forbidden band of the semiconductor. However, in the electrical energy injected into the LED device, only about 15% of the electrons and holes are radiated and combined to emit photons, and about 85% of the electrical energy is converted into the thermal performance of the thermal LED, which directly affects the luminous efficiency, wavelength, and forward direction. Voltage Drop, Reverse Breakdown Current, and Device Lifetime Traditional LED devices have less thermal impact due to less drive current and less heat. In recent years, with the rapid development of power LED devices, the influence of LED thermal performance has become more and more obvious, and it has received widespread attention.
The thermal performance of LEDs mainly refers to junction temperature and thermal resistance. The junction temperature refers to the temperature of the PN junction. The thermal resistance of the LED display generally refers to the thermal resistance between the state junction and the surface of the casing. The junction temperature is a parameter that directly affects the operating characteristics of the LED. The thermal resistance is the thermal dissipation performance of the LED. Good and bad parameters.
The reliability of the LED is greatly affected by the temperature, and the failure rate is also high when the temperature is high. The reason is not the LED chip itself, but the encapsulation resin or the resin cover, and the higher the temperature, the faster the aging.
The led display does not have incandescent lamps or fluorescent lamps. When using LEDs, it should be noted that the temperature should not be too high. In particular, it is necessary to dispose of heat-generating objects such as resistors around the LED chip. If the temperature of the LED exceeds the heat-resistant temperature, not only the light intensity is rapidly lowered, but also the phenomenon that the chip-connected gold wire is broken, the conductive silver paste of the fixed chip is peeled off, and the like may be extinguished. If the LED needs to be used at high temperature, it should be judged according to the actual installation situation and taken seriously.
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