Is Cree intentionally making green LEDs??

[h=1]I remember the good old days when the XR-E was king. It seems to me that the tint of the LEDs were a lot more white than they are today. I picked up a cheap energizer single AA light from Target and it has a pure white beam. I am not sure what the LED is, I think it is a new Rebel but it got me thinking about why so many of the new Cree LEDs are green.[/h]

Flashlight Dave said:

I remember the good old days when the XR-E was king. It seems to me that the tint of the LEDs were a lot more white than they are today. I picked up a cheap energizer single AA light from Target and it has a pure white beam. I am not sure what the LED is, I think it is a new Rebel but it got me thinking about why so many of the new Cree LEDs are green.

Click to expand...

Cree does not produce Rebel LEDs. Cree goes for efficiency, and at low drive levels, their LEDs green-shift.

Perhaps the tints are compromised in favour of efficiency improvements?

Besides for the limited run of XP-G S2s that we saw from 4Sevens I'm not really sure that I've seen a lot of green CREE LEDs lately.

Many years ago, when Luxeon was still king, there was a thing called the Luxeon lottery where you'd get get one of a variety of LED tints. I remember I had a Inova-made Victorinox light that had a Luxeon K2 LED that was a "pea soup" green color. That's how things were...
I think what you might be seeing is that a lot of cheap flashlight manufacturers will get LEDs from undesirable bins to keep cost down and that's why you've been seeing some funky colors.

I have a few XRE lights, and they all seem to have a purplish tint. While my XPG R5 and XML T6 lights all have green tints, except the Fenix Ld20 R4 which is more like pure white with a slight purple .

So I guess the green tint is related to efficiency.

Also, I find the the Luxeon Rebels in my Maglite XL lights all have a very pure white. Tint is much better than Cree chips.

My first LED lights had either blue or white tint, but not green. A VERY slight greenish is no problem but above such a level it's really bad. A pleasant tint is much more important than maximum efficiency so the LED-development seems to partly go in wrong direction. Just my opinion.

It seems to me that it's a problem they go through with every new generation of emitter. I saw it with the XPG lights I have/had and also with the XML's as well. Seems like it takes them a while to get it all worked out, because it also seems to me that as the manufacturing of each new emitter matures, they have progressively fewer issues with them producing green tinted output. Just my subjective experience.

My new Eagletac D25C XMLU2 Cool White and my new Nitecore EC1 XPGR5 Cool White are both the exact same white color, with just a very slight little hint of pinkish. So 2 different manufacturers with 2 different emitters makes me think that perhaps Cree got some things figured out.

However, my 4Sevens Quark Turbo X and Olight i1 XML I got last year are both greenish.

I have two of the NC D11 V2. Both have the now somewhat dated XP-G R5.
The first light's beam has a blue tint.
The second light's beam has a green tint.

I have swapped reflectors in my Olight M20 and ended up with a green tint to the beam. Then I swaped back to the matched reflector to the emitter and the green went away. Maybe in a rush to bring new emitters to market the reflectors are not properly matched to the emitters and this contributes to the green tint.

Lou Minescence said:

I have swapped reflectors in my Olight M20 and ended up with a green tint to the beam. Then I swaped back to the matched reflector to the emitter and the green went away. Maybe in a rush to bring new emitters to market the reflectors are not properly matched to the emitters and this contributes to the green tint.

Click to expand...

That is interesting....:thinking:

buds224 said:

That is interesting....:thinking:

Click to expand...

There's a tint gradation (From center to edge). You guys must not shine enough bare LEDs at the walls!

Chances are, the matched reflector is just not close enough to the LED to catch the green light. Try shining an optic-less XM-L straight up and put a vertical piece of paper right next to the LED and look at the paper from the side. Or google it. You'll find it looks like this:

SlowPoke808 said:

Click to expand...

Imon said:

Besides for the limited run of XP-G S2s that we saw from 4Sevens I'm not really sure that I've seen a lot of green CREE LEDs lately.

Many years ago, when Luxeon was still king, there was a thing called the Luxeon lottery where you'd get get one of a variety of LED tints. I remember I had a Inova-made Victorinox light that had a Luxeon K2 LED that was a "pea soup" green color. That's how things were...
I think what you might be seeing is that a lot of cheap flashlight manufacturers will get LEDs from undesirable bins to keep cost down and that's why you've been seeing some funky colors.

Click to expand...

Oh, its still that way with the XM-L today. I have gotten lights with XM-L LED's that are all over the tint map! I've gotten T-6's that were everything from very blue to very yellow to greenish. I sold my 2 Eagletac D25 ti's(A and C), because I ordered the so called neutral version, and they were way too yellow for my taste. I like a little warmth, and a slight yellow, but not like that. I also returned a T-6 light that was as blue as the cheap 5mm leds you get from the grocery store!

Recently received a Ti with the wrost coloured tint I've seen in a loooong time! It' even worse than the Nichia GS LED from a Nite Core T0. LOL!

bshanahan14rulz said:

Chances are, the matched reflector is just not close enough to the LED to catch the green light. Try shining an optic-less XM-L straight up and put a vertical piece of paper right next to the LED and look at the paper from the side. Or google it. You'll find it looks like this:

Click to expand...

^^And what causes that, and what can be done about it aside from buying a new LED?

eebowler said:

Recently received a Ti with the wrost coloured tint I've seen in a loooong time! It' even worse than the Nichia GS LED from a Nite Core T0. LOL!

Click to expand...

You mean a Thrunite Ti? I bought 3 of them, the 1st one like 2 months ago, and the second like 3 weeks ago, and the first one has a white hot spot with slight blue corona and spill, but the other 2 are both slightly yellowish in the hot spot, corona and spill. When all 3 are shined against a wall the difference is pretty big.

HighlanderNorth said:

I've gotten T-6's that were everything from very blue to very yellow to greenish.
I also returned a T-6 light that was as blue as the cheap 5mm leds you get from the grocery store!

Click to expand...

T6 has nothing to do with tint. In fact, with Crees, (Letter)(Number) is ALWAYS a brightness bin. (Number)(Letter) is ALWAYS a tint bin. I could conceivably purchase a 1D tint T1 brightness bin LED, but it's important to know that. Your mixup is like calling an 18-speed bike an 18-mile-per-hour bike; the categories don't switch like that.

^^And what causes that, and what can be done about it aside from buying a new LED?

Click to expand...

Buy from suppliers who sort tints, buy from suppliers who account for the reflector changes (My Stanley XM-L lights are creamy white), or slightly shim the reflector from the LED. When the green is in the hot spot you don't notice it; but if it's in the spill then it is far more noticeable.

Yes. Thrunite. The colour brings back lots of Luxeon lottery and "PEA GREEN" memories. (I was sure for a long time that the term was 'pee' green but obviously, that can't be the reference. lol.)I can't wait for new LEDs to change this one!