I accidentally ruined an old XP-G the other day and I thought the blue color was pretty neat.
If I intentionally were to blue shift another emitter just to use the color, how much (or little!) of the lifespan would it still have? Even if its a 75% reduction, 12,500 hours is still an extrodinarily long time to use a blue flashlight.
Just curious to see if anyone else has fiddled with the idea.
White LEDs are just blue LEDS with a layer of phosphor on top. When the blue light hits the phosphor, some passes through, while some is absorbed by the phosphor which emits red and green. The red, green and blue light all mix to produce white light.
If you want a completely blue LED, dedome a white LED, then scrape the yellow phosphor layer off the top of the emitter. I’m not sure this affects the life of the LED in any significant way.
Yep. Exactly what I was thinking. dedome, scrape.
Why not just buy a blue LED at that rate haha.
Be careful with the raw blue emitter around your monkey
(we know the risk threshold for blue-violet for monkeys. It’s one of those “do you feel lucky” issues for people)
I accidentally lost part of the phosphor on this Nichia LED and checked the spectrum — it looked “blue white” to my unprotected eyes.
Note it’s emitting down to the 382 nm cutoff for the instrument. Those are photons you want to be careful with.
(That’s with the $40 kit spectrometer from Public Lab; links on that page)
That output has a lot of energy in the range where caution is appropriate; lifetime accumulated exposure is the concern there.
’oogle “blue light hazard” for some information and far too much opinion.
(there is still some phosphor on the damaged emitter, and still some light through the usual visible range there)
It’s probably a UV LED in that case driving that one, since the output goes below 400nm; here’s an example from DigiKey of UV and blue based ‘white’ LEDs.
Dale scraped the phosphor of an LED to get a blue one. There’s a photo somewhere, but I don’t have the energy to search for it.
Thanks guys for explaining that. I had forgotten about the LED actually being blue anyway. Just another instance of engage brain before mouth (or text)
Still I’m kinda curious to know what severe overheating does to the lifespan…