8X Diode Murder fund

[sportcoupe]

Maybe 8x > 12x.

The 8x seems very hardy, mine is set high to 400ma and gives 508mw. Slipstreams was set very high and died, I think he half expected that.

I have mixed feelings about the 12x.

 

[ossumguywill]

We'll have to wait for 20X and see how they do- they could either be like 8Xs and be CRAZY PWNAGE POWERFUL or like 12Xs and be a step up, but not really worth it because they can't be overdriven well and cost alot.

wll

 

[Flaminpyro]

This thread is busting 20,000 views WOW ! :beer:

 

[IgorT]

Murder Candidate #2 70 hour PI plot:

Ith = 34mA
Slope Efficiency = 1.297mW per mA
Absolute Efficiency = 20.34%
Po @ 348mA = 409mW = 90.19%


This time the line is the bottom one, only still slightly overlapping an earlier plot. But the diode is holding up very well. Again, barelly any noticable power drop, almost makes me want to spread out the re-plotting intervals to 20 hours.




Murder Candidate #1 210 hour PI plot:

Ith = 37mA
Slope Efficiency = 1.192mW / mA
Absolute Efficiency = 17.62%
Po @ 300mA = 311.5mW = 87.50% of initial


Here it is again the bottom most line, there is some more spacing between them, the other diode, while obviously degrading faster, almost seems more stable in power with all the plots so closelly bundled together. Could actually be slightly tougher.



Some pictures i took after plotting...

Beamshots:

The diodes are doing great and the cycling continues. I may spread out re-plotting to 20 hour intervals for the second diode, to speed up the process, if the 80 hour plot shows this little difference again...

 

[IgorT]

Here's another way to look at what's happening with diodes.

I made two plots showing power changing over time with the data collected so far.


The first one shows percentage of initial power over time for both diodes:

The second just power dropping over time, with the 90% point marked for both diodes with the red and orange line:

Keep in mind, 8x #3 is the first murder candidate, 8x #1 is the second.


These two graphs will have to keep expanding as more data is added, until the end of the experiment.



In both cases the diodes dropped somewhat rapidly to around 90% of their initial power, where they then spend the majority of the time as degradation slows down.


You can see how the first diode degraded much slower at first, but crossed the 90% line at 110 hours, while the second is still holding above that line, and nearing the same amount of time...

It's actually possible, that the two curves will cross in the first graph, if the second diode keeps it up a little longer - that's why i said it feels like it's tougher, after seeing the tightly packed together plots.

But since degradation is changing speed, it's impossible to predict for sure.



Anyway, this should provide an idea of where to set a diode, if you want it to stay above a certain power over the majority of it's time.

It also makes better use of all those numbers i've been posting.



P.S. The diodes are nearing 220 and 80 hours.

 

[Shogoki]

woo.. i'm coming back from the dead to say this is awesomely great news.

did you ever get my email btw igort? well.. i'm ready to get my laser from ya whenever you're free

 

[IgorT]

The diodes are 80 cycles away from 90 and 230 hours.

I took down the 80 hour data yesterday but will post a double report today, due to time constraints.

 

[IgorT]

Here is the 80 and 90 hour data.

Basically little new to see here, the diode is holding up quite well, the 80 and 90h plots are the two pale bottom lines.

Absolute Efficiency dropped to 20.21%.
Po @ 348mA is 405.3mW or 89.37% of initial power..



The behavior can better be seen in these Po over time graphs:

Or in percentage of initial power:

The diode is very likelly gonna exceed 100 hours, which is incredible! I can't believe how tough they can be, and i thought i picked out the weakest ones...


I guess it's "safe" enough to set 8x's to 450mW or perhaps even 500mW+ for hobby pointer purposes afterall.

 

[Svensson]

That's great! Now let's hope the new 12× will perform significantly better than this...

 

[sportcoupe]

I guess it's "safe" enough to set 8x's to 450mW or perhaps even 500mW+ for hobby pointer purposes afterall.

That is the best news from a most reliable source I've heard in a long time. :bowdown:

 

[Canuke]

The number 3 plot looks like a copy of the #1 plot, scaled out in time 5x... unless it's just a coincidence of measurement error, it looks as though the #1 diode is degrading at 5x the speed, but the same pattern.

 

[ossumguywill]

The number 3 plot looks like a copy of the #1 plot, scaled out in time 5x... unless it's just a coincidence of measurement error, it looks as though the #1 diode is degrading at 5x the speed, but the same pattern.

That's what I thought, they have a similar shape just scaled differently. I imagine this is simply the break-in function of this kind of diode.

will

 

[IgorT]

The diodes are 150 cycles away from 250 and 110 hours, but i'm spreading out the re-testing intervals to 20 hours for the second murder candidate, to speed up the cycling, so next test will be at 120h.


In the meanwhile, here is the data from last night at 240 and 100h:

Murder Candidate #1 (LG 8x #3) 240h data:
Absolute Efficiency = 17.24%
Slope Efficiency = 1.171mW / mA
Po @ 300mA = 305.5mW = 85.81% of initial

Murder Candidate #2 (LG 8x #1) 100h data:
Absolute Efficiency = 20.06%
Slope Efficiency = 1.278mW / mA
Po @ 348mA = 402,3mW = 88.71% of initial


In the second graph i removed some of the plots and left only those at 20h intervals to make it less crowded. I left the 10h plot in it, since that's when the largest drop happened.



In terms of power vs. time, this is where we're at:

I added all of the intermediary data in these (i left some out before by mistake), and it shows that the largest drop for 8x #3 happened during the first 6 hours after which degradation already slowed down a lot.


Both diodes have noticably dropped below the 90% point by now, which is more visible here:

I also attempted to make a Lifetime Guesstimation plot that would show approximate lifetimes for these diodes set from 125 to 600mW, IF both tested diodes were to die at 240 and 100 hours.

But until i have the final numbers it's quite useless, as it doesn't have the correct shape yet, so it'll have to wait.

 

[IgorT]

The diodes passed 120 and 260 hours today! :yh:


Here is a re-plot of Murder Candidate #2:

Po @348mA = 401.3mW = 88.49% of initial power

Interestingly, this is one of the smallest drops overall. Only 1mW less than 20 hours ago! That's why the latest plot is overlapping the previous one again.



In the more interesting graphs, it looks like this:

Or in percentage of initial power:

At 70 hours, i said it's possible the second diode's curve will cross the curve of the first diode in this graph. Now it looks even more likelly!

If that happens, or even if it just gets (and remains) very close, i would guess that the second diode is slightly tougher than the first.

Up until now it degraded faster, set to a higher power that was only to be expected, but it held above 90% for very long, and it's degradation seems to have slowed down more after the initial rapid drop in power.



One other possible degradation byproduct i am noticing is an increase in spontaneous emissions. In this case in the form of a "yellow halo".

I noticed this "yellow halo" when plotting PHRs and GGWs in widelly varying intensities. At first i thought it was a sign of damage, but barelly any diode was completelly without it - it was spread completelly at random (i used to write it down next to each test to see if there would be an increase in deaths among those diodes, but there was no correlation).

It could simply be an indication of trace amounts of certain impurities in the die, but without any impact on diode "toughness".


I have no idea if it means anything at all, but in this case it seems to be growing in intensity, because i only started noticing it a few re-plots ago....

I will observe it more carefully in the following tests.

This yellow halo is most visible at low powers, or when looking at the spot through a filter that blocks 405nm partially or completelly, and appears as two different size blobs on either side of the slow axis.




Murder candidate #1 on the other hand (or rather 8x's set to 360mW) can pretty much be declared "immortal" at this point. Even if the diode dies soon, 260 hours is gonna be hard for anyone to reach in a handheld pointer!

But while that test is running at 300mA, this might not mean that all diodes will survive this current aproximatelly as long. A very high efficiency diode that produces 450mW at 300mA could degrade as fast as the second murder candidate does at 348mA.


That's the feeling i'm getting observing these diodes - as if the power they produce matters more than current for their lifetime....

 

[RA_pierce]

The diodes passed 120 and 260 hours today! :yh:


Here is a re-plot of Murder Candidate #2:

Po @348mA = 401.3mW = 88.49% of initial power

Interestingly, this is one of the smallest drops overall. Only 1mW less than 20 hours ago! That's why the latest plot is overlapping the previous one again.



In the more interesting graphs, it looks like this:

Or in percentage of initial power:

At 70 hours, i said it's possible the second diode's curve will cross the curve of the first diode in this graph. Now it looks even more likelly!

If that happens, or even if it just gets (and remains) very close, i would guess that the second diode is slightly tougher than the first.

Up until now it degraded faster, set to a higher power that was only to be expected, but it held above 90% for very long, and it's degradation seems to have slowed down more after the initial rapid drop in power.



One other possible degradation byproduct i am noticing is an increase in spontaneous emissions. In this case in the form of a "yellow halo".

I noticed this "yellow halo" when plotting PHRs and GGWs in widelly varying intensities. At first i thought it was a sign of damage, but barelly any diode was completelly without it - it was spread completelly at random (i used to write it down next to each test to see if there would be an increase in deaths among those diodes, but there was no correlation).

It could simply be an indication of trace amounts of certain impurities in the die, but without any impact on diode "toughness".


I have no idea if it means anything at all, but in this case it seems to be growing in intensity, because i only started noticing it a few re-plots ago....

I will observe it more carefully in the following tests.

This yellow halo is most visible at low powers, or when looking at the spot through a filter that blocks 405nm partially or completelly, and appears as two different size blobs on either side of the slow axis.




Murder candidate #1 on the other hand (or rather 8x's set to 360mW) can pretty much be declared "immortal" at this point. Even if the diode dies soon, 260 hours is gonna be hard for anyone to reach in a handheld pointer!

But while that test is running at 300mA, this might not mean that all diodes will survive this current aproximatelly as long. A very high efficiency diode that produces 450mW at 300mA could degrade as fast as the second murder candidate does at 348mA.


That's the feeling i'm getting observing these diodes - as if the power they produce matters more than current for their lifetime....

A bit off topic...
I recently built a pointer for someone with an SF-AW diode. At 155mA, the yellow halo was very noticeable. I have never seen this with PHRs or GGWs, so I was a bit intrigued. I thought it may be fluorescence from something in the module, but I could not find any possible source other than the die.
I didn't notice it with an Aixiz 405 lens but it was clearly visible with the 405-G-1. Maybe I just wasn't looking hard enough?
Hopefully the yellow halo is not a "bad" thing.

 

[IgorT]

woo.. i'm coming back from the dead to say this is awesomely great news.

did you ever get my email btw igort? well.. i'm ready to get my laser from ya whenever you're free

Hey Shogoki! You chose a good time to come back from the dead! :yh:

It IS great news! I am amazed more and more every day, when i wake up and see the diodes still alive!

Right now i'm waiting up for them to reach 140 and 280 hours and re-plot them. Don't want to have to pause the Torture Chamber and lose a night of cycling.


I got your email, and i wrote you yesterday, just waiting for your final answer.