Does this A140 look fractured?

[Gadget]

I took these macros with my Droid Ultra. My wife got me a set of lenses from the dollar store for 5 bucks. I was impressed, to say the least.

The face of this emitter appears to be fractured, and it's output has dimmed significantly. Could this happen from a freezing cold start? The fracture appears to be right in line with where the conductors attach.

Any ideas? Anyone seen anything like this before?

 

[BobMc]

Re: Does this M140 look fractured?

Wow, for 5 dollars I'm really impressed! Those lens work really well. Sorry but I can't see the fracture, so I can't comment on that. :can: But I can't get over how well those lens work. :drool:

 

[Lifetime17]

Re: Does this M140 look fractured?

Hi Gadget,
Sorry but thats a A140 diode not an M140 diode ,if your showing that this is your diode it has three bond wires it's an A140 , An M140 has four bond wires, don't know about the fracture ..

Rich

 

[Gadget]

Re: Does this M140 look fractured?

Oh...sorry Lifetime, you are correct, it is an A140. I had forgotten what I had in that particular host and didn't even pay any attention to the bond wires.

BobMc, I couldn't believe how well the macro lens worked, either. The fish-eye and wide-angle...not so much, but the macro alone was worth every penny of the $5.

 

[Crazlaser]

I got a phone photography kit last year, the kind with a selfie stick, crappy tripod and such along with a fish eye and macro lens and they work just like that. Surprised it's so clear for so cheap.

 

[Benm]

I does look like a fracture in the front face, but at an unusual position. The light emitting area should be 90 degrees rotated to the visible fracture, so i doubt it was caused by optical breakdown.

Perhaps due to thermal or mechanical shock, but very hard to tell unless you have pictures of an intact identical diode made with the same setup... it could also be some manufacturing artefact that actually is normal but normally not noticable (magnification on those pics is very good!).

 

[Gadget]

Thanks for the input, Ben. I was thinking thermal damage, too. As in a start in freezing temps. That's the only thing I can think of that may have caused it. Especially the way the fracture propagates straight back from the conductor junctions.

I'd try to get a pic of an undamaged A140, but that's the only decanned one I have access to.

Thanks again for the input.

 

[Benm]

It's possible it has just been caused by thermal expansion, those bond wires actually get quite hot during high current operation.

The spec sheets for these diodes usually don't mention a maximum rise time for the current, but most also assume temperatures to be 25 degrees and give some figures for performance derating for warmer environments.

I've used some slow starts or portable lasers in the past, mostly 405 and 650 nm single mode laser diodes that i found to fail only at powerup (and when driving them over spec).

These ramp the current to the diode from zero to max in a couple of seconds, but pose a big risk to users unaware of them: When you just click the laser on only a faint fuzzy dot appears (current below treshold), which could tempt the average idiot to look down the barrel, and 2-3 seconds later 200+ mW of coherent light comes blasting out