3W really is copper slug

I get tired of folks saying this and that, here is my 3W:




All my 1W are definitely Aluminum slugged..

Ahhhhhhhhh...so there is already ONE difference! Any more, Jar?

You da man for taking a file (or what was it?) to your Lux III!

Nice one Jar /ubbthreads/images/graemlins/thumbsup.gif

looks like it was done with a diamond saw /ubbthreads/images/graemlins/grin.gif

All of my 1Ws (all 50 of them) have silver coated copper slugs.



Lumileds has always claimed the slug to be silver coated copper.

http://www.lumileds.com/pdfs/techpaperspres/SPIEJan2001PM.pdf - page 26

[ QUOTE ]
evan9162 said:
All of my 1Ws (all 50 of them) have silver coated copper slugs.

Lumileds has always claimed the slug to be silver coated copper.

http://www.lumileds.com/pdfs/techpaperspres/SPIEJan2001PM.pdf - page 26

[/ QUOTE ]

Agreed, all the 1Ws, 3Ws, & 5Ws I've came across were all copper slugged coated with some silver coating.


R3J:

Now that is interesting. I had always assumed the better thermal properties of the LuxeonIII had been due to the move from an aluminuim slug to a copper part. So where does the improvement come from, if not the slug?

the marketing? /ubbthreads/images/graemlins/grin.gif

Do i detect some cynicism there keissling?? Surely not!

[ QUOTE ]
kakster said:
Now that is interesting. I had always assumed the better thermal properties of the LuxeonIII had been due to the move from an aluminuim slug to a copper part. So where does the improvement come from, if not the slug?

[/ QUOTE ]

Hell, it could be anything. Needless to say, Lumileds is probably keeping that a secret.

Besides, it's only a 2K/W improvement in thermal conductivity.

Theories:

1) Process improvement in the LED structure that slightly improves thermal transfer from the junction. This could be in the form of more pure materials, or an increase in the number/conductivity of solder blobs that attach the die to the silicon substrate

2) Better thermal conductivity of the silicon substrate between the die and slug.

3) Slightly better bonding material between the silicon substrate and slug.

4) No intentional improvement. Natural process improvement that has slightly improved the thermal conductivity.

That just covers the improvement in j-slug thermal resistance. The improved current carrying capability again, could be anything, but again, is likely a guarded secret (it keeps them ahead of the game).

Improved current carrying capabilities could be a result of the improved thermal management, purer materials/different materials mix, improved fabrication process, etc.

Hmmmmm...
/ubbthreads/images/graemlins/popcorn.gif

Let me go get a shot of a 1W purchased six months ago.

bbiab.

Sorry, but these 1W that are six months old *DO* have an *ALUMINUM* slug:

anyone notice [in this thread] if the die size is different?

rob

[ QUOTE ]
Jarhead said:
Sorry, but these 1W that are six months old *DO* have an *ALUMINUM* slug:



[/ QUOTE ]


HMMMMMMMMMM!!!!!?????
/ubbthreads/images/graemlins/popcorn.gif /ubbthreads/images/graemlins/popcorn.gif /ubbthreads/images/graemlins/popcorn.gif
/ubbthreads/images/graemlins/popcorn.gif /ubbthreads/images/graemlins/popcorn.gif /ubbthreads/images/graemlins/popcorn.gif

Must be when they test'em at the factory, those coming out brighter are now categorized as III's...

Very VERY interesting, indeed. Good one, Jar.

nice, when i worked (making non-LED diodes), i used do FMA on failures both customer and production line. sometimes the diffusion process went south..

one method ( there are several ) to check this was to epoxy pot and slice 'em with a diamond blade, grind away for hours then compare the die layers with a high powered microscope. [ wish i had access to some of that equipment now ]…anyhow you could measure layer thickness so it would be interesting to see if there was any difference between a standard and III….next …..there were staining techniques to apply for like copper migration into the die and so on but I digress..

rob

Okay fixed

Ah, guess what I noticed, these 1W they sent me have blobs of phosphor, not the thin "printed" layer. So they are definitely older 1W.

Nobody likes the guts shot?