Eli5: How do they test projector and other LED’s that claim to last 30,000 or more hours? Are they just taking educated guesses?
In: Technology
Very well educated guesses, yes.
One way to do it is to take a large sample and run them, and measure how long they last. Of course, that would take years to accomplish, since there are 8760 hours in a year.
So instead the process is accelerated. You still take a significant sample and run them. But you make some of the conditions more extreme than the normal operating conditions. Typically, voltage and/or temperature are used to accelerate failure rates.
If you do this a few times at multiple voltages/temperatures, you can calculate how much acceleration you get by increasing them. Then you can apply these “acceleration factors” to your experiment, and run enough devices to failure in a few hundred or a few thousand hours to figure out the expected lifetime of a typical component.
Of course, there are ways to screw this up. You can’t use such extreme voltage/temperature that you introduce new failure modes that wouldn’t normally occur. Your sample has to be reasonably large and reasonably random, so that it represents a “typical” part. You can’t have manufacturing issues later that create new failure hazards. Etc. Etc.
This technique has been used for years on various electronics devices, and it seems to work pretty well when applied correctly.
*Source*: I’m a former semiconductor reliability engineer.
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