Accelarated Life Test

This all depends on what feature of the LED life you are interested in.

There are tables for environmental exposure like salt spray, vibration, chemical, thermal cycling and such. See the SAE standards for examples.

The testing of LED life on a sample of 20 is probably an insufficient sample quantity to get any meaningful information since the MTBF is so high.

I was involved in LED assemblies for some years and managed a durability test lab at teh same site. We had one LED set on test for nearly 15 years without failure. (The specific model that it related to was obsolete before the testing was completed.)

Most significant in LED durability is the soldering process used to assemble them rather than the component itslef.

Probably the only way to accelerate life "time" exposure would be to operate at increased voltage/current (depending on your circuit design) to increase the component stress.

good luck in your venture.

HI JAE , thanks for ur input, Actually what i need is to do accerated life testing to would be equivalent to 24k hours use. I think thats what the below specifications is asking.

ALT (Accelerated Life Testing)

a. A Sample size of 20 units for ALT equivalent to 24000 hours.

If the device is expected to have a life of 24000 hours where 10% of that is in operation, then you could discuss that 10% of 24000 (100 days instead of 1000) would replicate the portion of life that would be spent "on".

So you need to understand the expected duty cycle of the LED in use and then compress than into 100% duty in your test. Discuss thoroughly with your customer.