~~~(Accidental) pull CREE LED dome off and it change to UV!!!~~~

I just accidental pull the head of CREE module off.

(It usually produce white light in the normal state......)

Then I think it will be junk and throw it away.

2 min. later something tell me to bring it back to my Ultrafire 502B and turn ON

see the picture what I discover!!!

(I am also test this UV light I can read invisible UV ink on the paper!!!)

I don't think that's UV, it's just blue. The phosphor is what makes otherwise blue-colored LED's look white. You pulled the phosphor off.

Of course, if you can read UV ink, I could be wrong. I wonder what the wavelength is.

Valpo Hawkeye said:

I don't think that's UV, it's just blue. The phosphor is what makes otherwise blue-colored LED's look white. You pulled the phosphor off.

Of course, if you can read UV ink, I could be wrong. I wonder what the wavelength is.

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"invisible" ink usually doesn't require real UV wavelengths, just some short wavelength blue.

Cree Cool-White LED's are actually Royal Blue below the yellow phosphor. The peak emission is at 460 nm and drops down to 0% at 400 nm. So it's not quite in the UV range. Check out the PDF Data Sheet link for XLamp XR-E's. There is a graph on page 5 showing light emission in relative radiant power vs wavelength. The sharp spike on the left is the LED's Royal Blue band pass pattern. The gentle slope on the right is light that fluoresces from the phosphor coating. The Cool-White LED (CCT range 5,000°K-10,000°K) has a peak at about 585 nm, which is not so surprisingly yellow.

Well it looks cool anyway.

I wonder how much this will shorten it's life span?

I've done the same thing but the tint color remained unchanged going by memory.

Looks funky.

I knocked the gummy dome off a rebel, and it took the phosphor off one corner of the die so I had a blue streak in my beam.

Jarl said:

I knocked the gummy dome off a rebel, and it took the phosphor off one corner of the die so I had a blue streak in my beam.

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It's a pity this happens as its so easy to do and such a pain to fix.