Anyone know the power of DVD Reader LDs?

Gazoo said:

Three things I will never forget:

My first DIY red.

My first greenie.

And my first blu-ray.

The beams from all of these is unique...simply awesome.

Congratulations..and have fun, but please be careful with your eyes... You will need goggles if you plan on burning anything.

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Well, i know how you felt.. It's how i feel right now.. And i still have one strong(er?) LD left. Untill i get more of course..


BTW: How strong is your greenie? Where did you get it and how much did it cost?

What about the blue one? I'm getting the blue one from the Sony PS3 - 10mW. How strong is yours?

Benm said:

A very promising result if you ask me!

I'm sure this laser diode is capable of burning something or lighting a match - that's just a matter of getting the focus right. Make sure that all of the light goes into the lens. If you set it up to have a focal point on the other side not too far from the laser (perhaps a foot or so), it should work fine.

280 mA sounds a bit on the high side for initial experiments to me. I don't know this diode, but it's a lot of current for a dvd writer diode in general.

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i started at 20mA and slowly worked up from there..

I mounted it on a large heatsink and monitored the temperature with an IR non contact thermometer.. It was around 33 celsius. So i'm not worried.. Actually i think it can do a lot more. Besides i still have one stronger one left... In case this one dies i'll know what to be carefull about next time.


BTW: Many people are driving them at 300mA with no more heatsinking than an AixiZ module. Some are even putting 400 or in extreeme cases 600mA through them when mounted to a huge heat sink..

And i still have a Peltier element ready for additonall cooling if needed...


So you're saying 280mA is more than is needed for burning?

Unfortunatelly I don't have a very good collimator lense yet.. Waiting for the AixiZ modules to arrive.... I think a lot of my light is getting lost as it is right now..


EDIT:
I read about someone using a lense from a disposable camera... Is that possible? I have a couple of those laying around...

It is not just heat that kills these diodes, its also the ouput light itself that can break down things... With the DVD 16x diodes from the group buy, you can light a match at 150 mA, no problem.

For the lens, one from a disposable 35mm camera might be difficult... remember that you have to put the LD roughly at the focal point, and it must then be large enough to capture all the light from the diode. The light comes out in a beam tens of degrees wide, so you're looking for a lens that is about as large as its focal point (for example 1 cm diameter at 100d or 2 cm at 50d).

Benm said:

It is not just heat that kills these diodes, its also the ouput light itself that can break down things... With the DVD 16x diodes from the group buy, you can light a match at 150 mA, no problem.

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150mA? That's interesting.. What voltage? Did anyone measure the output power at 150mA?

Benm said:

For the lens, one from a disposable 35mm camera might be difficult... remember that you have to put the LD roughly at the focal point, and it must then be large enough to capture all the light from the diode. The light comes out in a beam tens of degrees wide, so you're looking for a lens that is about as large as its focal point (for example 1 cm diameter at 100d or 2 cm at 50d).

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I'm worried the collimator lense from the cheap laser pointer is too small for this.. I have to do some more experiments..

Can you please elaborate on this a little bit more: "for example 1 cm diameter at 100d or 2 cm at 50d"
What does 100d or 50d mean? I'm new to lasers..


Otherwise, thanks for the info. I really apreciate it!


Igor


EDIT: And another question.. What diameter lense is in those AixiZ modules? Thanks!

i wondered the same thing and took apart an old DVD ROM drive that didn't work very well anymore and the diode worked pretty well, and it was a bit brighter than my <5mw 650nm keychain red so i thought it was a success, put the diode in a housing i got from a laser printer

MarioMaster said:

i wondered the same thing and took apart an old DVD ROM drive that didn't work very well anymore and the diode worked pretty well, and it was a bit brighter than my <5mw 650nm keychain red so i thought it was a success, put the diode in a housing i got from a laser printer

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Hehe, allmost everything we discussed here was off topic, since i started playing with my burner LD..

Finally a response i was waiting for.. Since i believe i allready killed one of these DVD reader diodes, i was wondering..

- How are you driving yours?
- What voltage? Current?

I tested mine with 3V and set the current to 13 mA and slowly worked up from there.. But i think i broke or damaged one of the legs inside during unsoldering, cos it acted weirdly.. I had to squeeze it for it to start..

I have another one, and will try it out, once i finish the burner one.. I believe it should at least make a nice laser pointer... Better than <1mW anyhow...


EDIT: What i should do is less talking and more laser building / testing..

it was running at about 60ma from i think 3 volts or so, i would run at like 50ma for better diode life though since any higher than 60ma made it mode hop, and i was running it from my home built power supply which uses 4 LM317 regulators in parallel

MarioMaster said:

it was running at about 60ma from i think 3 volts or so, i would run at like 50ma for better diode life though since any higher than 60ma made it mode hop, and i was running it from my home built power supply which uses 4 LM317 regulators in parallel

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Thanks for the info!

What kind of housing is that in your pic and where did you get that "heatsink" block?
Are you using four LM317 in parallel cos they are the small ones (100mA max) or are they the bigger version?


BTW: What is "mode hop"?

IgorT said:

Well, i know how you felt.. It's how i feel right now.. And i still have one strong(er?) LD left. Untill i get more of course..


BTW: How strong is your greenie? Where did you get it and how much did it cost?

What about the blue one? I'm getting the blue one from the Sony PS3 - 10mW. How strong is yours?

Click to expand...

I bought the X105 package from Nova lasers..it is highly recommended and we get a 5% forum discount.

http://www.novalasers.com/NOVAstore/pc/viewPrd.asp?idcategory=3&idproduct=16

The blue is actually a violet color...but is amazing. You will love it. Mine came from the GB sleds. I am guessing I am putting out around 7mw's. I really do not want to drive it very hard until I can fine tune the adjustment with my trim pots which have not yet arrived.

IgorT said:

As promised, i took another pic...

I took apart the Samsung TS-H552D v. B (16x DVD+R/12x DVD-R). I decided to use this one first, since i only have one version U (16x DVD+R/16x DVD-R) left and don't want to kill it again...

It could even be they both use the same LD.. But i decided on this one, just in case..

In the pic you can see how it's soldered onto one nickel plated brass plate, that is then soldered to another one, which is then screwed into the optical assembly.. All this probbably works as a heat sink for the LD..

I made a driver circuit to protect it, and will also use a Peltier TEC this time and a lot of heatsinks.. I hope this one makes it.. Wish me luck!

Click to expand...

My first diy red was one exactly like this, and believe it or not i managed to get it out of the heatsink intact.
I can't recall the order of these steps, but after sucking as much solder off as possible, bending the shit out of the heatsink with two pairs of pliers, and wedging a scalpel between the two while heating each joint alternately, it was finaly free.
After that the solder remnants on the diode made it an equaly difficult affair getting it into the aixiz module. lets just say a hammer was involved.
Now as it was my first go i hooked it straight up to two AA alkalines.
It was a fantastic burner for about a week upon which time it became an LED.
Quite amazing really that the heat and shock never bothered it, only being taken out eventually by COD.
Very tough diode.

Scog said:

My first diy red was one exactly like this, and believe it or not i managed to get it out of the heatsink intact.
I can't recall the order of these steps, but after sucking as much solder off as possible, bending the shit out of the heatsink with two pairs of pliers, and wedging a scalpel between the two while heating each joint alternately, it was finaly free.

Click to expand...

After my first one died, i also finished unsoldering it, since i didn't have to worry about it anymore.. Sucking the solder away as much as possible helped a lot, but a little always remains..

In the end, i heated the solder again and pushed it down on the table and it popped out..

But i'm worried about doing the same to the working one as well. I'd rather remove as much solder as possible with a small dremel tool...

Scog said:

After that the solder remnants on the diode made it an equaly difficult affair getting it into the aixiz module. lets just say a hammer was involved.
Now as it was my first go i hooked it straight up to two AA alkalines.
It was a fantastic burner for about a week upon which time it became an LED.
Quite amazing really that the heat and shock never bothered it, only being taken out eventually by COD.
Very tough diode.

Click to expand...

After all you did to it, are you sure it was just the COD that killed it? All the heating up to the solder melting point and then even hammering it into the AixiZ module might have weakened it a little, and allow the COD to happen sooner..

With my first one, i also tried unsoldering it at first, but then gave up. Then it died after only five attempts of turning it on.

There was that static shock as well, but since only the negative lead was attached to the PSU i believe the static went to the PSU. I'd prefer being wrong about this, cos shortly afterwards it died at only 100mA, while i drived the second one at 280 with no problems...

Now i allways ground myself, BEFORE touching anything (did that before as well, but forgot that one time..) so i really hope this one makes it..

My biggest problem right now is the correct positioning of the collimator lense, to get as much efficiency as possible (untill i get the aixiz modules that is)

BTW: Did yours come out of a Samsung TS-H552 as well? Did you measure the current going through it, being directly attached to the batteries?


Thanks!


Igor

I can't recall if it was the exact same model number, though it does look familliar. Not to mention the bent up heatsink i have in front of me is (was) identical to the one in your photo.

As for the death of the diode, i experienced a drop in power shortly before becoming just a dim led. still focused as a dot on the wall though.
From what i hear, its pretty rare for a diode to work for any real length of time just hooked up to batteries, so i don't think it was damaged by the soldering iron before that.
Unfortunately i did not take any current readings with that diode.

So with your diode did you actually feel a spark? cause thats what it sounds like, and if so i think you can rest assured that that is what killed it. Most esd damage is done by much smaller shocks that can't be felt.

Scog said:

So with your diode did you actually feel a spark? cause thats what it sounds like, and if so i think you can rest assured that that is what killed it. Most esd damage is done by much smaller shocks that can't be felt.

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Yes, i was sliding across the room on my chair, so i got pretty charged up..

Then i touched the negative lead of the PSU (that was connected to the LD) and felt a shock.. Since the positive lead of the LD was not connected anywhere, i was sure (well hoping actually ) the static electricity went to the PSU and not the LD..

But it is possible it went mostly to the PSU and a little to the LD. The shock was very strong..

After that i connected it (with the current limited to 100mA) and it worked perfectly for a while.. Then as i tried to put the collimator in front of it, the power suddenly dropped and it became a "LED"...

As i said, i am hoping it really was the shock that killed it. This way i have a better chance of the other two surviving..


Hmm, now that i think about it again, it could have been a reflection going back into the LD (as i was positioning it in front of the lense assembly) that helped killing it..

Wish me luck! I don't want to kill any more LDs...

Yeah by the sounds of that shock i think thats what did it, you should be good for your spare as long as you are carefull.
If all else fails just do what i did and buy a couple of diodes from senkat. I bought 3 killed one and now have had the second one running for weeks with one spare. http://sales.stonetek.org/

Anyway good luck, hope you can burn your name into your belongings soon.

IgorT said:

[quote author=Benm link=1193387877/15#18 date=1193493981]
For the lens, one from a disposable 35mm camera might be difficult... remember that you have to put the LD roughly at the focal point, and it must then be large enough to capture all the light from the diode. The light comes out in a beam tens of degrees wide, so you're looking for a lens that is about as large as its focal point (for example 1 cm diameter at 100d or 2 cm at 50d).

Click to expand...

I'm worried the collimator lense from the cheap laser pointer is too small for this.. I have to do some more experiments..

Can you please elaborate on this a little bit more: "for example 1 cm diameter at 100d or 2 cm at 50d"
What does 100d or 50d mean? I'm new to lasers..

EDIT: And another question.. What diameter lense is in those AixiZ modules? Thanks!
[/quote]

The 'strength' of a lens is indicated in dioptries, which are basically 100 divided by the focal point in centimeters. So a lens with a focal point of 3 cm would have a 'stength' of 33d. This focal point is for an incoming paralel beam, for example when you use a magnifying glass on aints using sunlight.

When making laser beams, you use it the other way around: Essentially the laser diode is a tiny light source that you position in the focal point, resulting in a paralel beam from the lens.

For easy calculation, lets assume that all the light comes out of the diode within 1 radian, or a beam 57 degrees wide. In that case, if the lens 1 cm away, the beam will be 1 cm wide, or 2 cm wide at 2 cm away etc. The lens must be large enough to capture the entire beam from the diode, hence this relationship.

For the aixiz module, i'd say the focal point is roughly 1 cm (100d), and the diameter of the lens is 6 mm or so. Most laser diodes have a beam less than a radian wide (usually more like 30 degrees or so), so it works out okay.

Scog said:

Yeah by the sounds of that shock i think thats what did it, you should be good for your spare as long as you are carefull.
If all else fails just do what i did and buy a couple of diodes from senkat. I bought 3 killed one and now have had the second one running for weeks with one spare.

Anyway good luck, hope you can burn your name into your belongings soon.

Click to expand...

Thanks!

I thought SenKat was through doing group buys... Bad experience or something.. I also looked at his site and the LDs are not available...

But i don't need to buy my red LDs.. I made an arrangement with my father's computer company's repair shop, to give me ALL the broken DVD writers that are out of warranty, since they would be throwing them away otherwise.. (I told them i need the stepper motors for building a rapid prototyper )

Just imagine, how many powerfull LDs are burried in landfills, while we could be using them for laser-engraving our names into stuff instead...

Anyway, this is how i got my three TS-H552 ones..

I am in a group buy for a replacement Sony PS3 blue laser diode assembly (10mW)... I hope i have my aixiz housings by the time i get it...