Finally, Diode Caps For Those Pesky "G-Ball" Diodes!

[Z80 Lasers]

At last, I've procured replacement diode caps that will hopefully work to replace the "G-Ball" lenses on certain diodes. I'm hoping they will just press on snugly after removing the old lenses and won't require anything to keep it attached. I will probably have to modify one of my diode presses so I can align and evenly press the diode cap on and not shatter the window or bend the cap.

I know the blue diodes should have an inert gas inside but I'm also thinking that wouldn't the diode just burn off the oxygen and drive out the moisture the first time it's fired? I eventually plan on creating some sort of tent or box I can fill with CO2 or Argon to assemble them in but for the time being I will just try it without and see how it goes. My biggest concern is keeping dust out of the diode while working on it and I think I have a pretty good idea how to do that.

I will update as I figure things out. Please feel free to share your thoughts.

 

[Unown (WILD)]

Are you thinking about making an air filtered enclosure to put the caps on? This would be awesome if you succeed in this. I've been wanting to buy a high power laser diode. I'll pick up one from you when you make these.

 

[farbe2]

Why do you not just buy the diodes directly from Lasertree already backfilled and with a hermetically welded cap already on there? Instead of buying the caps from them?

 

[Z80 Lasers]

Why do you not just buy the diodes directly from Lasertechnik already backfilled and with a hermetically welded cap already on there? Instead of buying the caps from them?

Because I probably have hundreds of g-ball diodes in stock already

 

[farbe2]

Hm I see.
I wish you luck but I would be surprised if that will work.
These diodes will die (as you know) when the facet gets exposed to oxygen. With your plan to just press the caps on without actually sealing them, I would guess that still enough Oxygen and water vapor makes it to the die to destroy it long term.

I had green diodes with removed caps die on me with just minutes of runtime on them but months of storage time. So it’s not just “when it’s on”.

 

[RedCowboy]

The 1W greens seem to do well de-canned but not the multi watt blues, for the multi watt blues you could do the work inside a dry nitrogen filled Plexiglas glove box.

Are the window cans attached via melted indium or with a low outgas adhesive ?
If melted indium then a little inductive loop could be used to seal each window can to the backing plate once you place an indium gasket and the window can on the backing plate...... maybe in a little clamping jig or gravity may be enough when you melt the indium gasket.

 

[Z80 Lasers]

I think using one of these dust boxes would do the trick. For the blues I could just seal the holes and purge it with Nitrogen or CO2. With summer being over the relative humidity in the air is getting pretty low so that will be less of a concern. Running an air conditioner or dehumidifier would further reduce any moisture in the air as well.

Amazon.com

 

[RedCowboy]

Yes you could seal the gaps and make the lid seal against some strips of weatherstripping, don't be afraid to use plastic bag plastic and duct tape to seal in the hinged edge so it remains flexible for opening/closing and purge with ......... dry nitrogen I expect would work.

 

[wolfram]

isnt argon a good choice as well? Z, you can always reach out to Lazerer if he still communicates. He Is an engineering genius!

 

[WizardG]

Has anyone determined, definitively, what causes the degradation of the blues when de-canned? The last thing I had read is that it's breakdown of CO2 by the intense light at the facet that dooms them. A little carbon reduced on the face of the facet would certainly be bad. But I hear about the diodes degrading when de-canned even when they're not used. Are the damage mechanisms different for used vs unused diodes? I read that gallium nitride is not very friendly with water vapor but I'd like to better understand why these diodes die.

 

[Z80 Lasers]

I created a jig to center align everything and I successfully re-capped a NUBM08 for testing purposes. I used a water-tight / air-tight cement because unfortunately they can't be simply pressed on like I had hoped. I'll have to see how well it stays adhered after running it for a while and getting it hot. The original G-Ball lenses appear to be laser welded on as far as I can tell. The diode is all scratched up from me attempting to push a cap on but that didn't go so well. The diode is running fine and no apparent dust particles in the un-collimated beam image.

 

[RedCowboy]

Has anyone determined, definitively, what causes the degradation of the blues when de-canned? The last thing I had read is that it's breakdown of CO2 by the intense light at the facet that dooms them. A little carbon reduced on the face of the facet would certainly be bad. But I hear about the diodes degrading when de-canned even when they're not used. Are the damage mechanisms different for used vs unused diodes? I read that gallium nitride is not very friendly with water vapor but I'd like to better understand why these diodes die.

From my reading the way I understood it, the blue lasers substrate stack is hygroscopic so after they polish the facet they apply a coating, however tiny particulates in the air will burn onto the facet at the p/n junction and cause damage to the coating which in turn lets moisture from the air in and causes fractures. The solution was the window-can cap and inert backfill.

I expect once the coating is damaged during lasing, that moisture from the air enters during off time.

 

[Unown (WILD)]

So as long as your quick enough in filling it with inert gas and capping it should be ok?

 

[RedCowboy]

I would do all the work inside the glovebox flooded with dry nitrogen or argon if possible.

In industry these diodes are made in clean rooms with carefully filtered air and everyone wearing moon suits.

 

[wolfram]

Good job Z !

 

[Darktron]

The original G-Ball lenses appear to be laser welded on as far as I can tell.

I don't believe this is the case some gball are easier to take off than others. Would think that if they are welded they would be so much harder to take off. It has to be a glue or solder like @RedCowboy mentioned.