What have I done to this diode?

GVLLD M981 · Oct 28, 2011

Well, I know what I did, I gave it too much juice on my LM317 test jig, is what I did. But more specificly, it still works, and makes as much light as ever, but it no longer has that "cluster" pattern, that it did, it looks blurred, now, and doesn't focus correctly. The glass window on the diode case is still intact. Quite frankly, I'm stunned that the the thing actually still works, asside from a few that darkened out, most of the diodes I have trashed just blinked out, and that was that. These things are tough as nails, aren't they? I can't wait to get a couple more of them. But I can'r for the life of me imagine what this one did that messed up the dot without any loss of power, that's just weird. Can you melt a cavity?

Eudaimonium · Oct 28, 2011

Hm, this is something new, can you take a picture of the diode's output without lens?

We have had a few 405nm diodes go zombie and produce weird patterns, but no 445nm diodes did that as far as I know.

Please take picz!

Blord · Oct 28, 2011

Looks like the laser diode turns into LED. You can't correct this kind of damage.

Things · Oct 28, 2011

^ You didn't read the post did you? There was no loss of (apparent) power, so obviously the cavity is still intact. The fact you can't focus it is odd, since if it's still producing considerable output, it means the cavity is still resonating ...

Pics would be nice.

GVLLD M981 · Oct 28, 2011

As requested, lens removed completely.

GVLLD M981 · Oct 28, 2011

And for a referance (for me, mostly) here is a shot of my other laser, the one that works. No lens, of course.

It's wierd what this one did, you know? They are completely different, now. They were identical, or close enough to it, before. Damn strange.
And when I ask, "is this even possible to do??" someone should chime in with
"Appearantly, it is now." At least I have a shot at being the premeire expert on blowing up diodes. Pioneering new ground, here.........

daguin · Oct 28, 2011

Eudaimonium said:
Hm, this is something new, can you take a picture of the diode's output without lens?

We have had a few 405nm diodes go zombie and produce weird patterns, but no 445nm diodes did that as far as I know.

Please take picz!

We have seen 445nm zombies.
These usually produce a lower output (e.g. 300mW) with full current and heat.
I sent one to pullbangdead.
He examined it under extreme magnification
Part of the wire-to-die contact was burned/blasted away
IIRC only one of the wire contacts was intact

The output pattern is effected as well with these zombies
However, as I said, they usually have low output with full current

If this one is still putting out high output, it would appear that this is a different phenomenon.

Has this diode (and your others) actually been measured with an LPM?
Unfortunately, "apparent brightness" is pretty much useless for this kind of measurement

Peace,
dave

DTR · Oct 28, 2011

Looks familiar. I have only had that happen once and it was during an experiment trying to run the microboosts in parallel with the negative side continuous. This was before I knew the negative input and the negative output had to be isolated on that driver. I had assumed that the cavity diode had become damaged but not to the extent to stop the diode from working. It was like the diode was melting when it happened as I saw it go from a perfect state to this without a lens on. Actually was pretty cool to see. Psychedelic man.

Maybe the cavity actually melted deforming it.:thinking:

I originally thought the window had something on it but I decanned the diode and it was the same.

daguin said:
Has this diode (and your others) actually been measured with an LPM?
Unfortunately, "apparent brightness" is pretty much useless for this kind of measurement

Peace,
dave

The one I had was still putting out 80%+ of its original output.

daguin · Oct 28, 2011

DTR said:
Looks familiar. I have only had that happen once and it was during an experiment trying to run the microboosts in parallel with the negative side continuous. This was before I knew the negative input and the negative output had to be isolated on that driver. I had assumed that the cavity diode had become damaged but not to the extent to stop the diode from working. It was like the diode was melting when it happened as I saw it go from a perfect state to this without a lens on. Actually was pretty cool to see. Psychedelic man. Maybe the cavity actually melted deforming it.:thinking:

I originally thought the window had something on it but I decanned the diode and it was the same.

The one I had was still putting out 80%+ of its original output.

Did you look at the wire-to-die contact under magnification?
I wonder if maybe only one contact burned/broke

Peace,
dave

**EDIT** -- I found the thread. The damage was more extensive than I remembered:eg:
http://laserpointerforums.com/f65/dave-mean-his-diodes-445-macros-image-heavy-54033.html

DTR · Oct 28, 2011

daguin said:
Did you look at the wire-to-die contact under magnification?
I wonder if maybe only one contact burned/broke

Peace,
dave

**EDIT** -- I found the thread. The damage was more extensive than I remembered:eg:
http://laserpointerforums.com/f65/dave-mean-his-diodes-445-macros-image-heavy-54033.html

No I did not. This was early on with the 445's. I ended up doing some torture testing with this diode and it died a few weeks later after being constantly abused and run up past 2A just to see where the unit shuts down. I was very surprised that it lasted as long as it did. They are really tough diodes.

Also if just one of the wires broke off would it have not gone from perfect to this state immediately when it went. It took 5+ seconds to go from that perfect state to this deformed looking state. That was the cool part. Like I said it was like the output was melting.

BShanahan14rulz · Oct 28, 2011

If it's not the lens melting, and assuming the same phenomena as DTR's photo of his decanned raw output, then it has to be that the OC melted or got damaged. Too much optical power through a small area. known as COD here. Probably only in the center because that is generally where a laser has the highest power density.

Dave, i think that one just got blasted with a bit (or a lot) too much current. While I'm willing to bet that it also would be exhibiting this type of output, if not worse, I think additional increase in input power is what eventually contributed to the electrode ablation.

*hums "What Is Love"*

GVLLD M981 · Oct 28, 2011

Actually, I might have gone as much as 15-20% over the max that my micro flex can make, just to see what would happen. Well, I know what happens, that's for sure. I rebuilt my test jig so that it can't do as much, now, but it'll still go a bit over the flex. I have a limiter switch on it, now, so in regular mode, it makes about 30% less than the flex. "Kill Diode" switch, just to have it. But I was the kind of guy that back when I was playing bass in a metal band, I liked killing garbage speakers with my bass head, just for giggles. "Flesh Fair"....

GVLLD M981 · Oct 28, 2011

Now I don't expect anyone to believe this, I sure wouldn't, but I'm going to put it out, anyway. I went to work trying to extract this diode back out of the module head I put it in. I don't have the proper diode tool, instead I have the end of an antenna, the diameter of which is the perfect size to just fit through the diode hole, so it goes around the can, and I basicly either use a 12mm socket, to press them in my vise, or I use a hammer. For whatever reason, this sucker refuses to budge, even the hammer wouldn't do it. I abused it as much as I could bear to, but no luck. Well I wanted to show my friend what it had done, that is if it would even come back on, after I used it like a framing nail trying to extract it. You won't believe this, but It works again!!! It not only still lights up, it got the original pattern back. Now THIS is really blowing my mind... hammering it with a hammer fixed it???? DAMN, these diodes ARE TOUGH AS NAILS, LITERALLY! Believe what you want to, that's what happened.

daguin · Oct 28, 2011

Maybe the window was damaged and the hammering broke the window out.

Maybe there was some foreign matter knocked loose and then knocked back out of the light path by the hammer

Maybe some foreign matter got cooked to the outside of the window

Peace,
dave

fixitiwill · Oct 28, 2011

These diodes, in my experience, can take a couple amps for a bit of time without being destroyed. From the diffraction pattern, (looks kinda like a fresnel lens), my best guess would be some sort of optic damage, whether it be on the die, window, or lens. Just my 2 cents. (conversion rate means it's probably only worth .85 cents, but hey...)

GVLLD M981 · Oct 29, 2011

fixitiwill said:
These diodes, in my experience, can take a couple amps for a bit of time without being destroyed. From the diffraction pattern, (looks kinda like a fresnel lens), my best guess would be some sort of optic damage, whether it be on the die, window, or lens. Just my 2 cents. (conversion rate means it's probably only worth .85 cents, but hey...)

Don't forget the 40% opinion tax on that, somehow they always add it up so that you owe them, and if you are ignorant enough to want that good credit score, you'll pay it.
I have no idea what happened to this diode, and if I hadn't done it to it personally, I wouldn't believe it was possible. I checked the glass on the can before, after, and between every hammer strike, assuming that at some point, I was going to break something, sooner or later. The funny thing is that one I'd tweaked it, and just wanted my heatsink back, and went to town, it refused to budge, this is the only diode I have ever failed to extract, at least that wasn't already dead, anyway. It was determined enough not to come out to start working again, this is too much, too wierd. Screw it, then, it can have the damn heatsink.

What have I done to this diode?

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