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NUBM08 decaned by accident,lets do some testing then

RedCowboy

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Perhaps there's a vacuum inside the can.

It's possible although an inert gas could also serve as a heat vehicle, also 1 bar or the weight of our atmosphere at sea lever is around 14 pounds per square inch, so a vacuum would exert force from outside of 14 pounds per inch, but an inert gas fill could be neutral pressure or just a fraction of a pound. It could simply be nitrogen which makes up 78% of the air around us, also I'm pretty sure that all moisture would be removed from the fill.

Facts from my smart brain word box :

By volume, dry air contains 78.09% nitrogen, 20.95% oxygen, 0.93% argon, 0.04% carbon dioxide, and small amounts of other gases. Air also contains a variable amount of water vapor, on average around 1% at sea level, and 0.4% over the entire atmosphere.
 
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paul1598419

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To run an experiment, you would need several diodes as one of each is not a large enough sample. It might solve the question if run correctly with enough samples of each.
 

Benm

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Your probably would.

I think the main reason for having the can and window there is simply to avoid moisture and perhaps dust ingress, as well as some mechanical protection for the die.

The fact that you can run this now canless diode more or less proves that air will not kill it like it would tungsten lamps filament or something like that.

Then again i've never seen datasheets mentioning what is in the can - i could vacuum, it could be something like argon or nitrogen, or it could just be air as you find in those older transistor packages.

I'd say chances are good that it is just (dry) air though: many semiconductors work fine when exposed to that, like chip on board mounted processors and stuff. They ussally put gunk over that to improve handling damage as well as moisture ingress, but sich devices usallly work fine if they forget to do that step.
 

RedCowboy

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To run an experiment, you would need several diodes as one of each is not a large enough sample. It might solve the question if run correctly with enough samples of each.


Sure a larger test batch with several diodes in each condition/group will make it easier to rule out the odd ball freak diode and give a more accurate average test result for each group and a better insight into the difference.

I have noticed a substantial difference in burning ability after the can is removed over the period of weeks to substantially reduced ability vs. the usual period of months of heavy use to reduced ability.

Granted we are not going to get anywhere near 20,000 hours MTTF or mean time to half brightness when we overdrive the diodes in a non temperature controlled device, however how hard we drive the diodes and the length of our duty cycle can have a measurable effect on longevity, but removing the can seems to greatly accelerate the reduction in output, something much less noticed by simply looking at the beam but better seen in burning ability and surly in LPM testing.

I am not interested in conducting a large test, but I have seen enough that I won't remove the cans anymore for my hard use purposes, but others may find it worthwhile and acceptable for torches and pointers.
 
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Some one new to this forum asked me for a link to single element aspheric lenses. I have been unable to find that post, but I do have a link to a BBAR coated lens in a 10 mm long housing for $7.90. I'm going to post it here as this is as good a place as any.

400nm-700nm Laser Lens/MP9x10mm/Laser Collimation Glass lens 1 pcs | eBay
thanks paul,it was me that interested to try this lens,what differences this lens has complared to G2's on power/divergence?

Sure a larger test batch with several diodes in each condition/group will make it easier to rule out the odd ball freak diode and give a more accurate average test result for each group and a better insight into the difference.

I have noticed a substantial difference in burning ability after the can is removed over the period of weeks to substantially reduced ability vs. the usual period of months of heavy use to reduced ability.

Granted we are not going to get anywhere near 20,000 hours MTTF or mean time to half brightness when we overdrive the diodes in a non temperature controlled device, however how hard we drive the diodes and the length of our duty cycle can have a measurable effect on longevity, but removing the can seems to greatly accelerate the reduction in output, something much less noticed by simply looking at the beam but better seen in burning ability and surly in LPM testing.

I am not interested in conducting a large test, but I have seen enough that I won't remove the cans anymore for my hard use purposes, but others may find it worthwhile and acceptable for torches and pointers.
i know how much time and diodes you spent in the past with those can diodes,i have read a lot of posts with your tests.i even remember somewhere you said that you had lost 3 nubm07 diodes after decaned them
 
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paul1598419

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@ Deadshadow

I'm glad you saw that link. I couldn't remember who had asked me and this lens is broad band AR coated for the whole VIS spectrum and NIR. For less than $8.00, it should be a good value. If you get any, let me know how they work out for you. :yh:
 
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@ Deadshadow

I'm glad you saw that link. I couldn't remember who had asked me and this lens is broad band AR coated for the whole VIS spectrum and NIR. For less than $8.00, it should be a good value. If you get any, let me know how they work out for you. :yh:
i have already bought it,when i get it i'll compare it with a G2 and post the results, hope it arrives soon because last 2 parcels that i got from this seller took 2 months to arrive....
 

paul1598419

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Oh, you're in Greece. Takes about 15 days for me to get items from them. At worst, it takes 25 days if there are long Chinese holidays.
 

GSS

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Oh, you're in Greece. Takes about 15 days for me to get items from them. At worst, it takes 25 days if there are long Chinese holidays.
Sorry to derail this thread a bit but Paul, me being Greek i'm curious to what you buy from Greece?:)
 

paul1598419

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I wasn't talking about getting things FROM Greece. Just how long it takes to get things from China as I get them quicker than they apparently do in Greece.
 

paul1598419

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That's a huge problem Peter. In fact I punished you by adding to your rep. Better not do it again. :crackup:
 
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hello everyone today i made a new power test and the results are 100mw down in power after a week,part of it could be a temperature deference and slighly different current from my psu but i do believe that the first signs of degradation started to showing up

 

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deadshadow

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2nd week test:



the diode seems stable compared to the previous test

edit: i'll editing the 1st post with the list of the results for quicker reading,so if someone want to see the tests he will easily read it on the 1st post :)
 

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