LW4000 becoming more blue?

My LW4000, wait a minute, actually all my white LED flashlights, seem to be getting more and more blue as time goes by. Is this a bad thing? I seem to remember reading somewhere around here that it means the LEDs are dying a painful death. Is it going to get worse? How much more life does a white nichia LED have once it starts to turn blue?

The LW4000 doesn't significantly overdrive its LEDs, so it shouldn't turn blue on you this quickly.

However, it is true that white LEDs tend to have a shorter lifetime than non-phosphored lamps, because the phosphor does eventually degrade, and in some cases (usually when the lamp is significantly overdriven for an extended period), the epoxy encapsulant may discolor.

Personally, I haven't had any white Nichias discolor noticiably except when driven far beyond recommended ratings. Degradation I've seen is usually in the form of reduced output without substantial color shift.

To me, the LED's of my eternaLights are looking a bit more blue, but I think it's because I've gotten used to the (not excessively pea green) light of my Arc SLS which has seen more usage lately.

Jake,

You didn't say how old your LW 4000 is or how much use it's had. Mine is only a couple of months old with light use and seems fine. I am hoping to use this particular light more and more though. I really love this thing!

Garyo,

My LW4000 is about a year old and gets used maybe 2-4 times a week, mostly quick jobs where it's never on for more than a few minutes. I think sotyakr may have something there. I have been using a newer LS lately and may just be getting used to the warmer color.

I believe you may be right about "getting used to" a certain color tint LED, rather than the LEDs becoming damaged....

My LW 4000 has significantly more blue-ish output than most of my other LED lights. The 3000 and the Trek 300 are quite yellow-ish in comparison, but even they appear very blue against my green-ish Arc AAA LE or my older amber-ish Luxeon Stars. Meanwhile my Eternalight has 1 bluish LED, 2 green-ish LEDs and 1 red-ish LED.

With LEDs there's a lot of variation in what we call "white"...

I wonder if it's possible to overdrive a luxeon and degrade the phosphor until the pea green tint disappears. I noticed that one of of the LS's that I had, it originally came with a green tint, and but after I killed it and after using silvirons techinique of zapping it with 6 volts, it came back life with a nice bluish white color. I've been driving it near spec for a while, and it seems to be fine.

Originally posted by InTheDark:
I wonder if it's possible to overdrive a luxeon and degrade the phosphor until the pea green tint disappears. I noticed that one of of the LS's that I had, it originally came with a green tint, and but after I killed it and after using silvirons techinique of zapping it with 6 volts, it came back life with a nice bluish white color. I've been driving it near spec for a while, and it seems to be fine.

Click to expand...

<font size="2" face="Verdana, Arial">I read Silviron's post(s) about the "zapping back to life method, but I still have one Q:
Will the "zapped" Luxeon then operate properly at the regular (3.3v), or will it always need 6 volts+ to work properly after zapping??

Be aware that it is wickedly difficult to accurately judge color tint (especially changes) without a reference standard. Our eyes play all sorts of fun tricks including something called lateral color adaptation. All this keeps the folks at MacBeth/Munsell in business sorting it out for the graphics/photography industry.

Mr. Glow
after zapping it with 6V, it works like normal again. I'm not sure what's going on, but after I fried the LS, I couldn't even get it to glow dimly with 3.5 V, but after hitting it with 6V a couple of times, it works even better than it did when new.
It is difficult to judge the color variation unless you have something to compare it too. The only reason I noticed is because I compared it to some of the other luxeons I had from the same batch, and I remember they all had the same green corona around them. I just noticed that the one I "fixed" didnt' have the green tint anymore. I guess it's not completely gone, but it a lot less noticable now.

One of the trick that I found was to put a magnifying glass in front of a multi-led light and project the image on the wall. The LED's from StreamLight 3LED light all had different tint. The spare Nichia 3MM LED's that I have also came up with different tint when lighted up in parallel.

To the naked eyes, they seem to have similar tint but when projected, the difference is very visible.

- Vikas