life exectancy of LED phosphor coated bulb??

what is life expectancy of LED phosphor coated bulb? Is there any radiation danger to the user ?

I'm not sure what you're asking.

Yellow phoshpor + blue die LEDs are typically rated at 100,000 hours in 5mm packages - assuming that they're run under laboratory conditions. High-power LEDs such as the Luxeon are usually rated from 50,000 hours (Luxeon I - 350 mA) to 20,000 hours (Luxeon III - 1000mA) to 500 hours (Luxeon V - 700mA, but greater lifespans are common). There's no radiation danger with these LEDs - UV (if any) is present in trace quantities below the detection threshhold of most equipment.

There are a number of other colors that use a blue LED with phosphor - purple and pink come to mind. Those products have yet to mature in the marketplace - lifespans have improved from the dozens of hours of pink that the original samples produced (rapid degradation of the organic phosphor) to lifespans similar to regular white LEDs.

The UV die + white phosphor LED is coming along. I dont' know what its lifespan is, but I know the UV hazard is no greater than with a conventional florescent tube. Unlike blue + yellow white LEDs, the designers do not want UV light to be emitted, so the phosphor is laid down in such a fashion to absorb as much UV as possible. I'm not sure how much UV is actually emitted, but I'm sure that it's minimal.

rated , BAHHH
100,000 hours of still barly putting out light is more like it.
give any of them 20,000 and they might be half bright.

i dont understand it, but phosphors are not permanent magic light outputers, they go away.
and rating any of this stuff for 100,000, in my opinion is a total lie. but then i burn them for Lamps not flashlights.
at any rate it beats the snot out of incadescent, halogen, and even florescent, and cct. but specs on how long, and how bright, should be displayed for how long AT how bright, like they are on regular bulbs we buy, that are supposedly TIME rated, at 50% output.

when SNEAKY flashlight manufactures provide spces, its just wrong, total lies.
they spec the led based on the die still operational.
they spec the output based on the first turn on.
they spec (battery) runtime, based on how long the led is still glowing enough to see over glow paints /ubbthreads/images/graemlins/smile.gif
they overdrive the LED, and dont change the "life" ratings.

and when the phosphors go, so to does the output, there is no reduced current usage when the phosphors are gone, just reduced light output. i think if parts of the gate (which will last basically forever) go, then the consumption might go down with it, depending on the curcuit used.

find me data sheets and specs that are exactally correct, or even speculated acuratly, and i will show you products that dont sell /ubbthreads/images/graemlins/smile.gif we like to be lied too.

try not to use 5mm leds for area lighting, at LEAST use high-powered leds.

Safe? there is tons of radiation comming out /ubbthreads/images/graemlins/smile.gif most of it in a visable spectrum. i think you could tie leds to a rats backside for the life of a rat, and he might just enjoy the light. but if you aimed them in the rats eyes, it would take that rat a bit of time to repair the retnal damage that might be done.
POINT lighting, has the greatest capacity to damage the eyes, because the adjuster thing (IRIS) in front of the light receptors doent adjust for single point source lighting.
so with tiny small filliments and humans staring into them like a fool staring into the sun in the desert, you could cause some damage.
just depends on how bright, and how well your iris is adjusting to it, to keep it at a level of triggering , vrses toasting.
the lack of certian frequencies of light, should make them safer overall.

[ QUOTE ]
VidPro said:
rated , BAHHH
100,000 hours of still barly putting out light is more like it.
give any of them 20,000 and they might be half bright.

i dont understand it, but phosphors are not permanent magic light outputers, they go away.
and rating any of this stuff for 100,000, in my opinion is a total lie. but then i burn them for Lamps not flashlights.
at any rate it beats the snot out of incadescent, halogen, and even florescent, and cct. but specs on how long, and how bright, should be displayed for how long AT how bright, like they are on regular bulbs we buy, that are supposedly TIME rated, at 50% output.

when SNEAKY flashlight manufactures provide spces, its just wrong, total lies.
they spec the led based on the die still operational.
they spec the output based on the first turn on.
they spec (battery) runtime, based on how long the led is still glowing enough to see over glow paints /ubbthreads/images/graemlins/smile.gif
they overdrive the LED, and dont change the "life" ratings.

and when the phosphors go, so to does the output, there is no reduced current usage when the phosphors are gone, just reduced light output. i think if parts of the gate (which will last basically forever) go, then the consumption might go down with it, depending on the curcuit used.

find me data sheets and specs that are exactally correct, or even speculated acuratly, and i will show you products that dont sell /ubbthreads/images/graemlins/smile.gif we like to be lied too.

try not to use 5mm leds for area lighting, at LEAST use high-powered leds.



[/ QUOTE ]

Couldn't agree with you more!

I have a small art piece in my living room that is illuminated by a 5 mm. "white" LED. I can't remember how many times I've had to change that led to maintain a reasonably white light with a good output /ubbthreads/images/graemlins/Christo_pull_hair.gif. The drive current is just below 20 mA, and yet it just gets bluer and bluer by time from the moment it's turned on. Output is decreasing too, but that's more difficult to see.

100,000 hours! - HA! They must be kidding.

Jan

Couple of things affect white LED `lumen maintenance` as it is officially known, how much for how long a source continues to output light.

Phosphors degrade, it happens with fluros as well, fluro tube can continue to emit light way past rated lifespan but the efficiency has gone down the pan, its still pulling power but the light output is way down.

Phosphor degradation can also result in the colour changing subtly, colour shift.

Other mechanism is the epoxy encapsulant used in 5mm LEDs, it by necessity starts water clear, by the mechanisms of heat and short wave light exposure from the LED die it yellows and/or clouds letting less light out.

Lumileds and now others use a differnt encapsulant system in their high power LEDs that should mitigate the effects of epoxy aging.

Most white phosphor LEDs use a blue LED die as the exciter for the phosphor, not any UV present and no radiation risk.

Even UV LEDs output very small amounts of UV that unless you stare into them from short range present minimal risk to the user.

Some useful info at the Lighting Research Centre at RPI, cannae put finger on link at mo , google should find it.

Adam

[ QUOTE ]
VidPro said:
rated , BAHHH
100,000 hours of still barly putting out light is more like it.
give any of them 20,000 and they might be half bright.


[/ QUOTE ]

Like I said - laboratory conditions. In the real world, most 5mm LEDs are terribly overdriven and/or the heat has nowhere to go - the package being crap for heat conduction.

i still disagree agreeably.
they showed us 5mm labratory tests here on the forum, and they were very bad. at spec below spec, over spec, under cooled, and overheated.
although i dont think there was any huge effort to sync the gate area, like in the high powered ones, which might help.

if i find the thread again, i will show it to you, newbie also posted some life specs, and charts.

it kinda turned me off to them, although there is better and worser ones, like the china ones vrses the nichitas, and the tests were OLDer.
but my experience at spec, is good enough to try and stick the high powered in anything i can from now on, even if i have to run them low.

i had always thought something was funkey, and the charts proved what i was seeing.

it doesnt matter much in a flashlight, especially keylights, or low use flashlights, but in the light that your going to use HOURS daily, avoid them like a plauge, untill sombody changes something.

dija ever notice how EVERY NEW 5mm led light whoops the pants off the old one you been using /ubbthreads/images/graemlins/grin.gif

There is *alot* more information on 5mm LEDs in other threads:

http://www.candlepowerforums.com/ubbthreads/showflat.php?Cat=&Board=LED&Number=950756

There are some manufacturers use phosphor to coat their LED light to make it pure white instead of bluish. According to your comments that these LED won't last long at all. why bother to spend that much cash if they onlylast 2 yrs. Is it better to spend of flashlight LED instead of headlight?

the phosphers is 1/2 of what is making them so efficient.
there is nothing wrong (per say) with using phosphors, they are GREAT /ubbthreads/images/graemlins/smile.gif
there is only something wrong with saying they last forever.

in a regular use flashlight, they should be a great assett, and more efficient than RGB combos, which are not so easy to work with.
in a light that your going to have on all the time, well then socket it

Well you can give LEDs a bad name by using that dodgy 100,000 hours figure, courtesy Clive Mitchell, Central Station, Glasgow,Ooops:

http://www.emanator.demon.co.uk/crapleds.jpg

Adam