Blue center hotspot in my Arc AAA Premium

I just received my Arc AAA Premium today, and noticed, that it has a distinct blue tinted center hotspot, with a more white light around. Is that to be expected on the premium?

It does happen.

All white 5mm LEDs will have a blue center to them. This is because of the way a "white LED" works. White LEDs are actually blue leds with a green/yellow phosphor. These colors mix together to produce an approximation of white. The balance of tint varies with the thickeness of the phosphor. As a result, the center of the beam is blue and the outside edge of the beam is green/yellow.

With the Premiums, we use the whitest white LEDs we can find. These are the Nichia SB1 bin 5mm type. There will still be some blueish tint to the middle, but compared to a standard LED, the level of blue is noticably less pronounced.

In some designs, the outer circle can be mixed with the center spot to make a whiter beam. This either requires secondary optics or a cluster of 3 or more LEDs. Secondary optics can reduce total output due to losses in the optics but clusters work well. However, clusters have been made obsolete by the new High Dome (lambertian) style LEDs from Lumileds. These LEDs produce a consistant tint across the beam.

But the Lumileds parts are larger and more expensive than a good quality 5mm LED for compact applications. We use both solutions in our line of flashlights.

Peter

Thanx for the explanation.

I just received two ARC AAs, with both having a bluish beam. I was wondering if that was normal since I don't remember anyone here mentioning that the ARC AAs were bluish....

I have a fair number of 5mm LED lights, and it seems like they each have a slightly different tint. Both my ARC AA Premiums have slight bluish tints in the hotspots, with one leaning towards the purple side.

-Mike

it's very common indeed Jan..

once you get a collection of LED lights going, you'll notice the personality traits of them.. some other tints are common too.. perhaps a slight yellow, green, or violet tint will be found on some LEDs you purchase..

my Arc AAA also has a slight blue hotspot.. i think it's one of the better ones i've seen tho.

you may hear a term on CPF that goes "Luck of the draw".. which basically is in relation to the tints of LEDs, and the less tint, the luckier your draw.

My Arc AAA and AAA CPF edition both have blue hotspots, but my Arc AA and Infinity Ultra have purple hotspots. The blue appears slightly brighter than the purple.

[ QUOTE ]
BlindedByTheLite said:
it's very common indeed Jan..

once you get a collection of LED lights going, you'll notice the personality traits of them.. some other tints are common too.. perhaps a slight yellow, green, or violet tint will be found on some LEDs you purchase..

[/ QUOTE ]

And then come the personal preferences, where you start swapping one for a few more to "check for a better tint." /ubbthreads/images/graemlins/grin.gif

-Mike