Taking off the (acrylic?) dome from a luxeon....

Mags

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I am not positively sure if this was done, so I am asking about it. Ive seen it a lot of times, and there was just the bare bare, not just bare emitter. The part of the luxeon, that little green thingy that emits all the light was actually BARE. I most recently saw it in this thread.

Solitaire mod LUX III

So if it can be done easily, can someone explain how to do it?
 

jaids

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my advice is to avoid removing it if you can. It is there for a reason, to protect the die and its little gold wires.

That said, if you cut into the black plastic about halfway up, all the way around you can get thedome off. use a new(read never used less than a week since bought) x-acto knife.
 

mike101

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I didn't take it off purposely. I drove the LUX in about 0.3A in that little Solitaire and left the light just lying on a table without further heat sink. I guess the LUX was over heated so the acrylic dome pop off. But the glue (epoxy) to joint the dome and base was soft. Is it normal?
 

WildRice

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I have done it a few times, albiet, not intentionally. I have done it to a LUX I white (broke wires), LUX I cyan, and a Cree hi-out white (turned blue, phos not on die). Most recientally was the cyan. There is a gel surrounding the LED (under the plastic part),

FOLLOW AT YOUR OWN RISK!!!

carefully and SLOWLY lift the dome off with an exacto knife, the gel should come with the top and remove itself from around the wires. I then used the knife to get the extra 'bits' off the die.

http://www.candlepowerforums.com/ubbthreads/showflat.php?Cat=&Board=UBB14&Number=965039&fpart=&PHPSESSID=

here is the cyan one I just did.

Jeff
 

IsaacHayes

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Re: Taking off the (acrylic?) dome from a luxeon..

youre just asking for a broke led either when you remove it or later... what is the reason you want to do this??
 

ViReN

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Re: Taking off the (acrylic?) dome from a luxeon..

I have done it too /ubbthreads/images/graemlins/tongue.gif ... wanna see it ?
have a look ...
DSC00093a.jpg


DSC00127a.jpg


DSC00093b.jpg

... well i damaged it ...

Actually I tried to pick up the emitter from QIII's Star to replace it with a TWOK and in the process while pulling the LED with Pliers after desoldering the terminals it looked like the LED came out easily but the black plastic came off with the acrylic dome i thought that that was easy and when i tried to fix a new Emitter over the star... DANG... there was still something sticking over thats when i realized that i had damaged the old emitter !!!...

and hence the result the emitter also shelved phosper and the LED used to work even after all this untill just after the photographs the emitter dropped off from the table.. and the top end was damaged...

also interesting to note that the slug is of Silver.. i never realized this before

and point is... there is no point actually... why do you wanna fiddle with the fraggile thing ?..... if you still want to do.. be prepared to loose 10 - 30 bucks (depending on the emitter you want to undo)
 

mike101

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Re: Taking off the (acrylic?) dome from a luxeon..

[ QUOTE ]
ViReN say, "also interesting to note that the slug is of Silver.. i never realized this before"

[/ QUOTE ]

How do you know it is of Silver? My another damaged LUX I looked like aluminum.
 

IsaacHayes

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Re: Taking off the (acrylic?) dome from a luxeon..

ViRen: Have you tried to solder or touch wires to the sides of the die to see if it will light?

The slug is Copper, that has been silver plated. Older luxeons I beleive were different I think they were aluminum center, or all aluminum. They do this to avoid corrosion.
 

ViReN

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Re: Taking off the (acrylic?) dome from a luxeon..

IsaacHayes .. yep it used to light before.. i wanted to take a picture... it looked soooo amazing... one of the most beautiful things that ever light up ... i did it using a CR2032 battery and some very thing strands of copper wire...

Mike .. i know because after days of atmospheric exposure... the slug was corroded just like silver ... gets black..

now that IsaacHayes has said... the slug is of Copper and plated with silver /ubbthreads/images/graemlins/smile.gif
 

greenLED

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Re: Taking off the (acrylic?) dome from a luxeon..

[ QUOTE ]
WildRice said:
I have done it a few times, albiet, not intentionally.

[/ QUOTE ]

/ubbthreads/images/graemlins/yellowlaugh.gif You took the words out of my mouth. T'was a nice TWOJ too /ubbthreads/images/graemlins/frown.gif It obviously doesn't work, but I think I still have it somewhere in my "broken" container.
 

Mags

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Re: Taking off the (acrylic?) dome from a luxeon..

Thank you for the replies everyone. I wanted to just test out the results. Someone sent me a box full of stuff to experiment with /ubbthreads/images/graemlins/wink.gif and thats exactly what I am doing. I was wondering what the beam pattern would be and thought that raw unaffected brightness might be fun to deal with. Does anyone know if it will be any brighter or better? I think the little dome focuses the light of the emitter, so light might be lost, but Im not sure. Anyway, the box came with many Q binned emitters that I can do anything with. So I have the worst tinted one right now in front of me. This also brings up another question. The die of the LED is green right? So if the dome focuses on that green little thing with the light coming out of it, wouldnt the beam be green for that reason? So is it possible that no focusing would mean white light? Just a theory or though here...
 

IsaacHayes

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Re: Taking off the (acrylic?) dome from a luxeon..

White leds have a blue led with yellow phosphur. not green led. I don't think you'll gain much light at all, not noticeable. The dome doesn't focs any, it's lambertain.

If it's green then it means too much yellow phosphur was applied over the blue led from the factor. Too little would make it look blueish.
 

WildRice

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Re: Taking off the (acrylic?) dome from a luxeon..

If you do this to a white, it is most likely that most if not all of the phosphor will stay on the die itself, it can be picked off with a sharp pin and a good eye loupe. I used my cyan in conjunction with a small spherical optic rightup against it. almost no light lost and good throw.
Jeff
 

Mags

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Re: Taking off the (acrylic?) dome from a luxeon..

I did it /ubbthreads/images/graemlins/smile.gif I cant really notice any difference in terms of brightness, but I cant really test out that much because it is a bare emitter, not a star and coiling, or trying to coil the wires of the micropuck around the positive and negative leads was a pain plus I had to hold the input wires against the positive and negative sides of the battery. So picking off some of the yellow stuff will make it slightly un-greener correct?

This whole thing is a great helper to small mods or solitaire mods hehehe Im starting to get ideas now.
 

mike101

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Re: Taking off the (acrylic?) dome from a luxeon..

Do you guys mean that the LED still makes same light without the phosphor (yellow stuff)?

I was always thinking it was the phosphor to produce light.
 

McGizmo

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Re: Taking off the (acrylic?) dome from a luxeon..

[ QUOTE ]

.... I don't think you'll gain much light at all, not noticeable. The dome doesn't focs any, it's lambertain.

[/ QUOTE ]

On this, I beg to differ! I too was of this impression but a fellow mentioned to me on the phone that the dome from a HD will fit over a Cree dome and provide some tightening of the beam?!?!? I assumed it was due to the dome shape itself but for the heck of it, I took a dome off and removed the silicone goop and low and behold, there is a baby plano-convex lens at the top! Now I am wondering if these LED's wouldnpt put more light into the reflector if they did have the lens removed as it is in fact a lens! /ubbthreads/images/graemlins/icon15.gif

On top of that, once the dome is gone, you can see how the die is up on a pedestal and I suspect that portions of the plastic case could be removed and some good thermal material or bog might be allowed to contact the die base and aid in thermal relief?!?

Certainly a before and after beam shot and lux measurement would shed some light on this but the lambertian distribution is being aided by a primary lens!
 

Mags

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Re: Taking off the (acrylic?) dome from a luxeon..

AHA! thanks Don for proving my theory.
 

IsaacHayes

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Re: Taking off the (acrylic?) dome from a luxeon..

Mags, If you remove the phosphur it will emit blue light!! Not white.
Mike101: yes, the yellow on top of the blue led gets excited and together they combine to make white light.

Mags, make sure you protect the led now with the dome off, a small sneeze and the wires will be blown off!!
 

McGizmo

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Re: Taking off the (acrylic?) dome from a luxeon..

Mags,
In retrospect, I chose a poor host for testing but I took an Aleph 3 with DB917 and measured max lux of 5040 with the stock Luxeon. I then removed the lens and got a max reading of 5250.

I suspect that any real advantage of lens removal would be seen when a shallow reflector was used and more of the light that normally would head out as spill would then be available off axis in the absense of the lens. /ubbthreads/images/graemlins/icon3.gif If I am right, I should have done the experiment with an Aleph 1 and its shallower 27 mm reflector. Oh well. /ubbthreads/images/graemlins/smile.gif Having the sink pedestal open for contact with some type of thermal contact also seems to have advantage for those wanting to push the limit.
 
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