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NEW LOC Laser diode review.

Hemlock_Mike

Hemlock_Mike

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This is a review of the first red diode in a sample of 3 sent to me by Greg at Stonetec. He sent me the 3 samples received and this is the first one taken at random.
The part number is: LPC822 --- It is a new, virgin, diode with long legs, never inserted in a housing. (no comments) --- It was represented to Greg as THE replacement for the LOC diodes we know here.
I pressed it into an Aixiz housing and screwed in a 650-G1 lens. The housing is clamped in a small 4" hobby vice for additional heat sinking.

I have never seen a LD act as this one. You will have to look at my "old school" data provided. I repeated this data 3 times !!!

2909-lpc822-1.jpg



The kink, knee or whatever you call it is a broad curve. If I drop the current, the power comes back up. The curve does not full retrace back. I will push this diode to limit.

2910-lpc822-2.jpg


The assembly starts warming over 500 mA but not excessively. The diode with the G-1 lens also exhibits the "wings" normally found with LOC's .

HMike

R2007 -- thanks for the help!!

More data !! 700 mA --- 135 mW and 750 mA ---88 mW !!! Back down the current and the power output comes back up.


HMike
 
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The results are interesting.
This diode was run at 650mA?
Was/is the power drop permanent damage?
 
Looks unusual, but these don't seem to be a replacement for LOCs especially if someone wants to push them. Is this effect due to heat perhaps? What's the driver? I'm surprised the bonding wires haven't acted like a fuse at that point.

@RA_Pierce, if it has been repeated 3 times with the same diode and the result was the same each time then it isn't permanent damage causing the tailing-off. Either that's the true relationship between current and output, or heat/driver causes this pattern.
 
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If you want to send me some data Mike I can put it in a pretty computer graph for you :D
 
Hemlock_Mike said:
The system has trashed my report. I need to kill much of it and two crap threads created somewhere ... WHY CAN"T I KILL THE CRAP? This isn't the whole report.
HMike
Click to expand...

I posted on those 2 other Threads on how to remove them or
get them removed...
I saw no other info but your 1st post asking how to remove them...
It seems the mods have removed them...

[EDIT]
10 minutes ago.. I saw a graph on your 1st post here... now it's only
data values...:thinking:


Jerry
 
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graph.jpg


graph2.jpg


Someone might want to redo them, its been awhile since I've used Excel!
 
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I just ran the test agaun after a half hour cruze around the lake!!... Almost the same numbers !!! This time I pushed to 700 mA -- 135 mW and 750 mA -- 88 mW !!!
I dropped the current and the power output comes back!! Go Figure. It does get a little warm but not hot in these 30 second tests.
I'm using a power supply with addustable current and voltage. When I set a current, I wait for 10 seconds for my reading. These diodes are not too stable up at high current but they survive!!

HMike
 
Pontiac----

Nice work -- You can add:
700 mA 4.05V 135 mW
750 mA 4.1V 88 mW !!!
Can you believe this??

HMike

I'm going to go toast this POS..........
 
Ok.. WTH is happening to all that power that ISN'T coming out as light??

If its not excessively warm at 500mA, and if Vf continues to increase... then why isn't this thing either putting out, or bursting into flame?

Does anyone know how this works? How goofy...
 
Tyler -- It does start heating quickly over 500 mA --- NS !!!!
I have never seen an LD fold back and/or recover with a couple minutes off. 900 mA and no fuse action by the wires to the die? I swear, I'm gona kill this one.

HMike

Damn --- I cranked it to 1.1 Amps and it was a bright LED. No Lase. Turned it down to zero for 5 seconds and it lives!! As I turned it down quickly, It started to lase again. At 400 mA -- 230 mW which is close to my original data.

This may be the LD for a noob !! It just seems to avoid COD and comes back. This is only the first LD out of the 3 sent to me however. Most unusual..............
 
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That seems incredibly hardy indeed, but what interests me is *how* it's surviving the "fuse" action of the leads, and what would normally cause COD, and allowing it to come back with very minor degradation only. Where's PBD when you need him? :)
 
Could it survive power spikes? That would make for kip-kay style builds :P
 
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