My diode isn't round?!?

Hey fellas, I just bought a samsung 20X DVD burner. Ya I know samsung bad choice I wont make the same mistake again but anyways, I got the thing apart and extracted two things that I think might be my laser diodes. I'm wondering if somebody can show me in a pic or even link me to some pics of a flat square laser diode so that I can see if I've got the right part. Thanks.

Yeap, at least some Samsung DVD burners don't use round can diodes, they have wide, rectangular diodes that can't really be used very easily.

I get what you're saying. That sounds exactly like what I found. It like a strip of black plastic with a tiny diamond looking thing in the center on one side and four little prongs on the other. Just to confirm though can anybody please post some pics of what these diodes look like. Thanks for the help fellas.

Well, they look different from each other, depending on how they are mounted into a heatsink. But when i found one in an 18x Samsung, i took a picture and posted it here.

I'll go look for it and attach it here.


But yes, you can be sure you have the right bit. That's what they look like. Were both square or was one round? If one is round, that is the IR.


EDIT: I can't find my picture, but this is a picture of one, that VaThInK posted on CPF
I have several diodes of this type, some from 16x and one from a 18x DVD. They are pretty much the same, but the metal (heatsink) is different.

Also, take a look at this thread, where Phenol took some closeups of the plastic frame and the laser chip inside:
http://www.laserpointerforums.com/forums/YaBB.pl?num=1207306830/0#0

Here are a few pics of a diode taken from a Samsung SH-S202J burner by skram0:







And here are a few more taken by GMH of a Samsung 20x lightscribe burner diode:

My first good diode was round, but it was soldered into a heatsink, and i didn't dare to remove it, so i had to do something similiar to the last pic.

It can still be turned into a laser, but will require much more patience just centering it behind the lens. I would suggest mounting it in a way that provides some heatsinking tho.

Anyone know if these can be pushed further than the regular round ones?

Hey thanks for the pics. REALLY helpful. The diode that I have extracted looks almost exactly like the one in the first pic IgorT posted. Whats all this talk of heatsink. I know that this is like laser 101 but as I have mentioned in my previous posts, I have never done anywork like this before and am trying to learn about lasers so... If somebody could explain the heatsink and how I would begin to attempt to install this into the Aixiz module that I bought that would be fantastic. I'm working to put together the MXDL mod here. > http://www.laserpointerforums.com/forums/YaBB.pl?num=1186966870 So that should give you an idea as to my final goal.

if urs looks like the first one and has 4 prongs, of which only 2 are used, it's probably a Sharp diode rated for 125mW CW . the one i got from a sony nec optiarc drive looks just like it. i ran it at 250mA for awhile and it's still alive.

Thats a bit depressing. I only dished out the extra cash for the 20X burner instead of the 16X because I thought that I would be getting a lot more than 125mw out of it. How is that even possible? Wouldn't I be somewhere around 100mw with the 16X burner? :-/
Also whats qualifies it as a sharp diode?

just_here_2_learn said:

Thats a bit depressing. I only dished out the extra cash for the 20X burner instead of the 16X because I thought that I would be getting a lot more than 125mw out of it. How is that even possible? Wouldn't I be somewhere around 100mw with the 16X burner? :-/

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Just so you know, you can safely get 200mW out of the new diodes from sales.stonetek.org if that will make things easier.

Hey thanks styropyro I just can't afford to buy another part. I would like to buy one and apreciate the heads up I just can't. If 125 mw is all I can get out of the one I have so be it at this point I kinda just have to work with what I've got.

just_here_2_learn said:

Thats a bit depressing. I only dished out the extra cash for the 20X burner instead of the 16X because I thought that I would be getting a lot more than 125mw out of it. How is that even possible? Wouldn't I be somewhere around 100mw with the 16X burner? :-/

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Well, we've been pushing <120mW rated diodes at close to 200mW succesfully. The diodes are made to withstand more, than the rated power. The rated power is just the guaranteed power, at which the diode will reliably last for a very long time in a DVD.

You might want to buy a Sony NEC Optiarc 719x (x=0, 1, 3), but not the 720x, because it has the same flat thing. It's a 20x drive, and you can get them at NewEgg for very cheap, and they have an open can, capable of up to 300mW quite safely, and more with lots of cooling.

Just make sure you ask around and make sure, before you buy the next drive. The one i mentioned above is under $30.

Also whats qualifies it as a sharp diode?

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The fact that it's most likely made by Sharp.

just_here_2_learn said:

Whats all this talk of heatsink.

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The diode heats up from all the power it dissipates. How much depends on the current. That's why it's in that chunk of metal, screwed into the sled, with some thermaly conductive "foil" in between.

When you stick a normal round diode into an AixiZ module, the module will provide some heatsinking, which is usually enough for 16x diodes, but for open cans you need to mount the module onto some more metal, so the heat can spread and flow away from the diode.

As the diode heats up, it's output goes down. It can also damage it, if it heats up too much, or shorten its life.


If you should decide to use this diode, you should find something out of metal, and glue it to that using thermal epoxy, or drill some holes and screw it into that.

You are going to have problems turning this into a laser, so it might be better, to get a proper diode. Make sure you know how to handle it safely first. Open cans can be damaged simply because the chip is exposed, and there are some hair thin golden wires going to it, which can get ripped if you're not careful.

125mW is the official rating, which all diodes will withstand safely, live long under the worst conditions in a dvd writer and keep sharp clean of customer claims. if you dissipate the heat away from the LD effectively, it will probably be able to give in excess of 200-250mw

So basically, what you guys are tellin me is that this diode will not work with this set-up? > http://www.laserpointerforums.com/forums/YaBB.pl?num=1186966870? :'(

Yes it can but you can't use the aixiz module for this kind of diode. You need to find a way to heatsink the LD and another way to collimate it.
That to me is a fun and challenging project, [smiley=evil.gif] but if I was you I would just buy the 20x Sony Nec Optiarc DVD burner from newegg.