Service life – how temperature development affects the service life
The service life or also the light degeneration of an LED refers to the period after which the illuminating power sinks to half of its original value. The functional capability of an LED depends on several factors. The semiconductor material used is as important as the operating conditions or the degeneration of the silicon crystal.
The actual value of the service life cannot be generally determined, though. While standard LEDs may last up to 100,000 hours, high-power LEDs can be used for only about a quarter to a maximum of half of that time (25,000-50,000 hours). If both diodes were to be used non-stop, they could be used continually for eleven and more than two years, respectively.
The service life greatly depends on the location and the provided current density. The higher the current flow, the more the diode heats up. This shortens the service life. The ambient temperature is also relevant for the service life, as the diode fails sooner the warmer it is in general. Basically, the intensity of the light radiation in LEDs continually decreases over time. This is an advantage, as unlike traditional lamps (incandescent bulb, halogen), an LED doesn't suddenly leave you standing in the dark. Even if the illuminating power is reduced, it normally does not suddenly fail. The plastic normally used in the lenses of LEDs gradually becomes hazy, which also affects the luminous efficiency negatively.
Main factors affecting the service life
- Current density
- Degeneration of the silicon crystal