Luxeon hat swap (changing emitter domes)

[evan9162]

You too can change a high-dome into a side-emitter!

I changed a 1W high-dome star into a side-emitting star

here's how:

Find a victim side-emitter, with poor green color. Carefully pry the lens from the emitter by prying up with a sharp knife or needle all around the lens.

Find your good, white, bright high dome emitter that you would like to make into an SE. Even more carefully, pry the high dome lens from the target emitter. make sure to not put any pressure on the sides of the lens where the two "ears" are - those are the places where the bond wires attach to the emitter body - no need to break those off /ubbthreads/images/graemlins/wink.gif

Here's the target emitter (left), the freed high dome lens (middle), and the new SE lens (right, with a slight chip in the cone portion)

A close up of the lenses reveals that the interior space is identical, and thus, they are interchangable

The SE lens on the emitter

Success! The luxeon is still alive!

Not sure what I'm going to do with this - but hey! It was a neat experiment!

 

[koala]

So what happen to the greenie?


Vince.

 

[Rothrandir]

very nice!

i assume this wouldn't work with ld's due to the different structure?

 

[yclo]

It should work with a LD too, but only with a 1W. If you attempt to make a 5W LD, you'll end up with this:

http://www.candlepowerforums.com/ubbthreads/showflat.php?Cat=&Board=UBB6&Number=241490

-YC

 

[evan9162]

Actually, Roth is right. 1W HDs and SEs have the emitter die sitting on top of a pedistal. The LD is sitting inside a small cup. They are incompatible for this swap.

I managed to ruin the greenie - I applied too much pressure where the "ears" of the lens were, and popped a bond wire loose from the emitter housing (still attached to the die). That's where that piece of advice about not pressing on the lens ears came from /ubbthreads/images/graemlins/tongue.gif

 

[InTheDark]

You might want to try clearing out the gel in the emitter cap with a swab to prevent crushing the die or breaking the bond wires. You should have enough room to put a low dome on top of a 5 watt. You can replace the gel with some UV index matching epoxy like the ones they use to repair winshield cracks.

 

[evan9162]

I did clean out some of the gel in the emitter cap beforehand (forgot to note this). The bond wires aren't super strong, but they won't break just from breathing.

A low dome lens isn't actually a hollow dome shape inside (like the HD and SE are). The lense element directly over the emitter die extends down into the cup to nearly touch the die. The die in a 1W HD, SE, and 5W sit well above where the 1W LD die sits.

 

[InTheDark]

Hmm...I'm pretty sure I had put a low dome on a 5W green before, but maybe the greens were different or maybe I didn't press it down all the way. Or possibly my memory just sucks. I just remember having a problem where I kept breaking the bond wires because of all the excess gel. Have you noticed a reduced output after all of this modifying? For some reason, a lot of the ones I played around with would slowly degrade in output after a while, but I dunno why. It could be the epoxy, but it's happend even without it.

 

[evan9162]

You might not have pressed it down all the way. The portion of the LD lens that extends down stops even with the bottom of the lens rim.

As far as degrading output, there may be a reaction with air and the phosphor or LED substrate its self. Considering that, for the most part, the (potential) air underneath the dome is displaced by the silicon encapsulent...but I'm just guessing at this.

I'm sure there is some reduced output, since there are some air bubbles under the SE lens, which means more reflective/refractive interfaces for the light to pass through. In addition, the SE lens loses some light compared to the HD anyways, due to its optical design.