Pioneer 8X Blu-Ray-- BDR-203

[jayrob]

There's not a whole lot else going on with it.  I'm waiting on info to decide on which driver/host combo to use.

Peace,
dave

Ok Dave, it's a done deal...

I am ordering this pot now:
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=3339H-101-ND

And I will build a DDL driver with it and mount it into a 3405 host with a version 1 heatsink and have lead wires on there for you.

This driver will adjust from 12.5mA's to 400mA's. It is a 4 turn pot and will go over 400mA's so watch out for that. It is just recommended for no more that 400mA's in this circuit because it is a 1/2 watt pot.

I will set it at 125mA's, and you can adjust it from there with your test load.

So using 3 X 10440 batteries, you will have plenty of voltage to drive your awesome 8X diode up to 400mA's with this circuit!
Jay

Edit: I'll send the 405-G-1 glass lens mod with the package!
Lens mod - http://www.laserpointerforums.com/forums/YaBB.pl?num=1236386077/0

 

[Spyderz20x6]

[quote author=Spyderz20x6 link=1236464366/80#94 date=1236883428]
So, it is single mode, right?

In practical application, Yes. (see pullbangdead's post above)

Peace,
dave
[/quote]
Well, we are obviously talking about practical application...

 

[daguin]

Well, we are obviously talking about practical application...

Fortunately for us, we have a nice mix of laymen AND scientists in the forum

Peace,
dave

 

[charliebruce]

Just to mention, I contacted one of the main Chinese suppliers to see if they can source any of these sleds for us. I will post back on here when I get any more information.

 

[climbak]

So, it is single mode, right?

I think you are mistaking what type of modes I am talking about. For all intents and purposes this diode is most certainly single TRANSVERSE mode. This is the one you care about with laser pointers. I need single LONGITUDINAL mode for the work I do with the diodes. Diodes are very multi-longitudinal-mode in general. This means it is lasing at a lot of closely spaced wavelengths and the total light output is spread out over roughly a half nanometer. I need lasers that run with one particular wavelength which then has a spread of about 10 picometers or so. I could explain it in more detail, but I don't want to jack the thread more than I already have haha.

Anyway, back to the topic at hand. Build a pointer! We need comparison shots with other BRs!

 

[daguin]

Laymen AND scientists . . . .

Thanks, Climbak

Peace,
dave

 

[drlava]

Wow, just saw this thread through your PM. If this diode does in fact require 7V that would be quite surprising! Typically, no matter what the power, all of the diodes of a given wavelength will have the same operating voltage. The FlexDrive V4 has a maximum output voltage of 6V, so if this diode really takes 7 then it's not going to work. That said, another thing we have noticed in diodes is that their operating voltage increases the more they are overdriven. It's possible that your test diode has a rated operating voltage around 5V but you've managed to overdrive it so much that the drop has increased to 7V. Again, I'd be very suprised if this was the case and it lived! get a multimeter on that sucker. I'd love to do a V-I-P plot with that thing.
Good find, thanks for testing for us Dave.

 

[daguin]

Wow, just saw this thread through your PM.  If this diode does in fact require 7V that would be quite surprising!  Typically, no matter what the power, all of the diodes of a given wavelength will have the same operating voltage.  The FlexDrive V4 has a maximum output voltage of 6V, so if this diode really takes 7 then it's not going to work.  That said, another thing we have noticed in diodes is that their operating voltage increases the more they are overdriven.  It's possible that your test diode has a rated operating voltage around 5V but you've managed to overdrive it so much that the drop has increased to 7V.  Again, I'd be very suprised if this was the case and it lived!  get a multimeter on that sucker.  I'd love to do a V-I-P plot with that thing.  
Good find, thanks for testing for us Dave.

Thanks for the response, drlava. All of those are possible. We are blind with these from the beginning. The voltage requirement estimate is simply intuitively derived from the Rkcstr's drop out of regulation at 330mA with 9V supplied. The Rkcstr needs 2.5V. To me that said that the diode must be drawing over 6.5V. It went well over 330mA with 12V supplied, but we have seen "artificial" toughness before from these violet diodes. I'll set one up and see if it lives :-/

Peace,
dave

 

[drlava]

Were you using a 9V battery?  I assume not
It's best to measure the diode voltage directly, please try that and we'll know for sure.

Edit: I see you used a bench PSU at 9V

 

[Hemlock_Mike]

We have seen in the past that Vld is not linear with the current. It is amazing how a diode can draw much more current with a tiny increase in voltage.
For the noobs here --- This is one of the reasons why we drive laser diodes with current sources.

Mike

 

[daguin]

Were you using a 9V battery?  I assume not
It's best to measure the diode voltage directly, please try that and we'll know for sure.

I was using my 2A bench PSU. I originally set it at 9V, because that had always been enough and because the Rkcstr is a linear driver, I try to limit any excess voltage.

Peace,
dave

 

[drlava]

please send me a PM when you are able to do a direct diode voltage recording.

 

[daguin]

please send me a PM when you are able to do a direct diode voltage recording.

Remember -- I'm a speech teacher -- How would I do that?

Peace,
dave

 

[pullbangdead]

Wow, just saw this thread through your PM.  If this diode does in fact require 7V that would be quite surprising!  Typically, no matter what the power, all of the diodes of a given wavelength will have the same operating voltage.  The FlexDrive V4 has a maximum output voltage of 6V, so if this diode really takes 7 then it's not going to work.  That said, another thing we have noticed in diodes is that their operating voltage increases the more they are overdriven.  It's possible that your test diode has a rated operating voltage around 5V but you've managed to overdrive it so much that the drop has increased to 7V.  Again, I'd be very suprised if this was the case and it lived!  get a multimeter on that sucker.  I'd love to do a V-I-P plot with that thing.  
Good find, thanks for testing for us Dave.

If the diodes are well made and built consistently, they'll all be the same, and that will correspond to the light coming out. But high voltage is certainly a common thing with diodes. Especially with new diodes or research efforts, I would not surprised at all if the forward voltage were higher. Once a working diode is made, a lot of work goes into getting threshold down, and getting Vf down. But if they can make it work, make it reliable and long-lived even with voltage a little too high, it'll still work just fine.

For 405nm light, you're looking at a minimum voltage of only around 3 volts, since 405nm corresponds to a photon energy of ~3.06 eV. So you can see, all these diodes have extra voltage built in above and beyond the bare minimum for what light is coming out By contrast, a 650nm photon has an energy of ~1.91 eV. If I remember right, that gives you only about 1 extra volt of built-in voltage in the diode for the red diodes, where you can have more than 2 volts "extra" for violet if the diode takes 5 V total. Improvements in making the diodes will bring the voltage down, but it's not surprising that newer diodes of a different "model" or different stack may have higher built-in voltage.

These things are finicky at every level, it can even be quite difficult just to make the contacts to GaN, especially the p-GaN. Contacts on production diodes should be very good, low resistance, and most likely ohmic. But if the contacts are even just a little off, it's not hard at all to get some extra voltage built into the contacts with a Schottky barrier. The same is true everywhere else in the diode stack, it's not unusual at all to have an extra volt or 2 showing up.

 

[drlava]

[quote author=drlava link=1236464366/96#107 date=1236979291]please send me a PM when you are able to do a direct diode voltage recording.

Remember -- I'm a speech teacher -- How would I do that?

Peace,
dave[/quote]

connect a multimeter in voltage mode across the diode while you are driving it with 300mA

 

[daguin]

connect a multimeter in voltage mode across the diode while you are driving it with 300mA

It's the simple things . . . .

Peace,
dave