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is this one 445nm diode or I received wrong diode?

alx

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Hello all,

Long time did not posted here. Now I'm back with a strange problem.

Yesterday I received few "445nm" diodes.

Start to mount first one in an AIXIZ nut. - done
Preseted current on LM317 driver at 600mA - done
Join togetger diode + driver - done
powered from a bench supply using 7.5-8V as input

After few seconds (3-4seconds) lasing, first 2 diodes died!

Now strange things: current even preseted at 600mA before connecting 445nm diode, will sit at 130mA and diode is lasing! (not so strong, but lasing). Very unexpected behaviour!!! I know that all casio A130 and A140 diodes has treshold current over 200mA! This one start lasing under 200mA which makes me to suspect that I received wrong diodes.

Grab another diode. Same scenario, input voltage 8V. Start lasing.
Preseted current 600mA (max adjustable value 800mA)
- flow trough diode ONLY 130mA, lasing
- start rotating pot and increase curent up to 250-260mA (max I could get and corresponding to 800mA max value position)!!! mesured optical power 70mW!

Replaced driver with other model (CW current regulator too). Now at 7.2V input I am getting 130mW at 430mA using 405G1 glass lens! Still under xj-A130 or xj-A140 specs from other forum members! Trying to increase input voltage increased the current. When reached 500mA/8V diode died instantly!

I want to mention that booth drivers used are CW, and with other diodes are working - red, blue (405nm) and IR - without any problems.

In the afternoon I will try to take some pictures from diodes I received. On the back side it has a stamp. Maybe someone can recognize them and confirm or infirm my doubt: are those diodes A130, or A140 or ARE NOT 445nm diodes and seller sent to me by mistake some 405nm diodes!

Regards,
Alx
 
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Toke

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Odd, I have never heard of any other 445nm diodes than the Casio ones.
That leaves some error in connections/measuring as the only explanation.
(And it is on average a very likely explanation)

Have you asked your supplier if they have heard of other 445nm diodes and if so have them around?
 

alx

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Odd, I have never heard of any other 445nm diodes than the Casio ones.
I suspect that are NOT 445nm diodes! Maybe 405nm! At 430mA I am getting out only 130mW from that diodes which is still very low!
 

Prototype

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There are several 445nm diodes, Osram and Nichia make smaller 3.8mm ones and I believe Nichia also makes a 9mm can one.

Edit:^Toke


Edit2: @alx, what color is the dot? The beam can have a purple-ish hue but the dot should be a brilliant blue color.
 

santanas

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Hi Guys. If you want a bulletproff driver and it sets voltage at threshold every time for RGB diodes and you adjust the curents to what you want. Go to the FlexMod p3 you will like it, I tried to kill it but could not. Never had 8 volts to a 445nm yet but 600ma cool. Have a better day. JH
 

Toke

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I suspect that are NOT 445nm diodes! Maybe 405nm! At 430mA I am getting out only 130mW from that diodes which is still very low!
I see, there are lots of different 405nm diodes.
The 12X can handle 600mA for a while and give out something like 6-800mA max.
130mW out sounds like a 4X, which should run at something like 100mA
(Above figures is "As far as I recall" and you should check the relevant treads for power graphs)

Your best bet would be to contact your supplier for an explanation.
 

alx

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I see, there are lots of different 405nm diodes.
The 12X can handle 600mA for a while and give out something like 6-800mA max.
130mW out sounds like a 4X, which should run at something like 100mA
(Above figures is "As far as I recall" and you should check the relevant treads for power graphs)

Your best bet would be to contact your supplier for an explanation.
The 4th diode is DOA! Connected using another LM317 driver preset at 410mA (all caps discharged before to connect diode). No current flowing through circuit. Increasing/decreasing input voltage (from 6V up to 8V) does not change anything (no current flow through circuit at all). I still own only one diode and really don't want to unseal it. Before I want to take some snapshots. My digital camera not working so will be a delay (few days maybe till will be returned from service). I never encountered such kind of problems. Does A140 diodes have some "special" in comparison with blue or red diodes? I intend to order another driver type and try it with my last diode!
 
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daguin

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I suspect that are NOT 445nm diodes! Maybe 405nm! At 430mA I am getting out only 130mW from that diodes which is still very low!
Get a macro shot of the rear of the diodes (or mail one or more to me). We can at least tell if they are "marked" like a 445nm.

Having so many go bad is MORE than unusual. I suspect that either, as you fear, they are not 445nm diodes OR there is some problem at your end with your procedure, the driver, or power supply.

Peace,
dave
 

alx

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This is what I want to do. To take few macro photos of them. My Canon 450D is not working. I'm angry. Definitely I will post few photos here.

My power source is a PBS so anything related to it is excluded (enough power 5A up to 30V, stabilized voltage). Drivers also tested and work like a charm with blue, red and IR diodes! Something definitely is bad here... must be documented to all lpf members ...

Still only one diode in original bag (I'm suspecting bag to not be antistatic too) ...
 
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alx

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Can you post a pic of the diodes? Was the case pin cut?
Yes, the pins are short! All 3 pins of diode are very short (shorter THAN TO-18 capsule itself), not the same like I saw other 445nm diodes (which are 2 times longer than TO-18 capsule).

Also the shape of the spot is like the one produced by 405nm blue-ray diodes AND NOT LIKE the spot produced by 445nm diodes (long flat square).

I am in doubt that I got the correct one! Why are you asking about pins?
 
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daguin

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Yes, the pins are short! All 3 pins of diode are very short (shorter THAN TO-18 capsule itself), not the same like I saw other 445nm diodes (which are 2 times longer than TO-18 capsule).

Also the shape of the spot is like the one produced by 405nm blue-ray diodes AND NOT LIKE the spot produced by 445nm diodes (long flat square).

I am i doubt that I got the correct one! Why are you asking about pins?
With the 445nm diodes from the Casio projector, the anode and cathode pins are long. The case pin was cut short before being installed into the projector. The pins should NOT be all short.

There is also a "salmon" colored "spacer/spreader" on the pins that may or may not be left on after harvesting. The case pin is cut at the top of that spacer. The other pins were unmolested

If all three pins are shorter than the can, it is either not a 445nm from a Casio or the person had to cut them off that short (not likely). If they cut them off that short, it would be UNDER the solder blob. If they were cut that short, the pins should be without solder showing on them.

Peace,
dave
 
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alx

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With the 445nm diodes from the Casio projector, the anode and cathode pins are long. The case pin was cut short before being installed into the projector. The pins should NOT be all short.

There is also a "salmon" colored "spacer/spreader" on the pins that may or may not be left on after harvesting. The case pin is cut at the top of that spacer. The other pins were unmolested

If all three pins are shorter than the can, it is either not a 445nm from a Casio or the person had to cut them off that short (not likely). If they cut them off that short, it would be UNDER the solder blob. If they were cut that short, the pins should be without solder showing on them.

Peace,
dave
All the pins are the same size short! All has solder on it! All diodes I received has the same size of pins! All 3 pins are shorter than the can!

Finally, I found a solution and take same snapshots!

See photos attached. Zoom inside to see all details you want!

Oh: now i realized that scaling it (to match forum rules, no larger than 800x600), a lot of details has vanished. Dave, Patt, can you PM your private email address in order to sent photos at original resolution (4.2MB/picture). Using actual one you will not be able to zoom in and see details!
 

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DrSid

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You say that you have 7.5V and 250mA on the diode at the same time !? These diodes should have about 4V at 250mA. 7.5V without current limit would kill them.

My guess would be your lab source is the culprit. Maybe it just can't give more current.
 




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