LED light decay refers to the LED after a period of light, the light intensity will be lower than the original light, and low this part is LED light decay.
LED Light Failure Reason:
At this stage of the LED product light decay degree are different, high-power led also have light decay, inhibit light decay helps to reduce the cost of unit luminous flux. All led manufacturers are committed to suppressing the phenomenon of optical decay technology, but did not disclose the cause of the phenomenon of light decay and the details of the suppression method. However, some manufacturers have disclosed that the chip heating and current concentration and other parameters related to the phenomenon of light decay.
For example, when you enter larger power, the amount of light in the chip increases and the heat is increased. This heat causes the internal quantum efficiency of the chip to deteriorate, resulting in light decay phenomenon. Therefore, some manufacturers believe that, in order to inhibit the phenomenon of light decay, the use of high heat dissipation packaging structure, even if the input of large power chip temperature will not increase the improvement will be effective in suppressing the phenomenon of light decay. In addition, there is a point of view, if the LED chip in the current density of larger, it is easy to cause light decay phenomenon.
Cree Company LED's junction mild light decay life test results
The University of California's Santa Barbara Institute says they have found the underlying cause of the underground use of LED technology for general lighting. They conclude that the light decay (LED droop) is caused by the auger compound (Auger recombination). Auger recombination is a phenomenon that occurs in semiconductors in which three charged particles react to each other without releasing photons. The researchers also found that the indirect auger effect, which included scattering mechanisms, was significant. This finding makes it possible to explain the discrepancy between the LED optical decay and the actual measurement results by direct auger process in previous theoretical studies. The researchers believe that because the auger effect is a mechanism of formation, the phenomenon of light decay is not eliminated, but can be minimized.
At present, regarding the LED product light fades the stipulation, applies the most widespread standard for American Energy Star's lm-80-08 and the GB gb/t24824-2009.
