40mW Sanyo 635nm LDs on Ebay

midias · Mar 7, 2011

anselm said:
Well, the driver from the green, I thought. It's negative side, close to voltage of IR, just need to
turn down the current a little, no?

Yea as long as the case is LD positive and batt+ you should be good to go. I believe it is so I think it will work just fine.

aryntha · Mar 8, 2011

Good luck, guys, and post some pics -- good to see some 635 action.

And, if anyone has any of these diodes they want to sell, please let me know! I just need *one*!

DTR · Mar 8, 2011

Just thought I would throw this out there for those of you that want to run this diode without having to Isolate the module or heatsink. There is a driver that Aixiz sells for $6 for a two pack that regulates via the negative side so you can have the unit in a case positive host without the need for Isolation. It runs a comfortable 100mA. Here is my post that I threw up in RA's build thread. http://laserpointerforums.com/f52/galileo-40mw-638nm-sanyo-diode-61221.html#post868726

I plan on building mine in an Ehgemus 14650 Pen host. And that host is a direct press head so Isolation is not real feasible.

mfo · Mar 8, 2011

aryntha said:
Good luck, guys, and post some pics -- good to see some 635 action.

And, if anyone has any of these diodes they want to sell, please let me know! I just need *one*!

I have a 20mW diode from DJNY's GB I'd be willing to sell. I purchased three of them before I bought the 40mW diode, so I don't need all three anymore.

midias · Mar 8, 2011

Still trying to decide what to do with mine I already have a pen version and I kinda wanna try to push it but it is so rare. Who knows maybe another pen I do have to order some anyway so I can make a 685nm pen.

anselm · Mar 8, 2011

OK I think I got the greenie driver figured out, but I don't have any diode housing at hand.
Would it be a terribly stupid idea to power the naked diode for a short period of time?
Just to see if it lases....

In the worst case, I guess I could dismantle my 445nm labby and use the o-like housing.
But the lens is AR coeated for the wrong color (blue/violet)....

Hey aryntha, would you still be interested to buy it after I soldered leads on it and had my way with it
for a little while?

midias · Mar 8, 2011

anselm said:
OK I think I got the greenie driver figured out, but I don't have any diode housing at hand.
Would it be a terribly stupid idea to power the naked diode for a short period of time?
Just to see if it lases....

In the worst case, I guess I could dismantle my 445nm labby and use the o-like housing.
But the lens is AR coeated for the wrong color (blue/violet)....

Hey aryntha, would you still be interested to buy it after I soldered leads on it and had my way with it
for a little while?

I would not power it without some type of heatsink

midias · Mar 14, 2011

Well playing with mine a little I pumped it to 150 ma it is over 70mw now and does not seem to get warm. I wanted to make a plot but I cannot get my usb to serial converter to work.

mfo · Mar 14, 2011

midias said:
Well playing with mine a little I pumped it to 150 ma it is over 70mw now and does not seem to get warm. I wanted to make a plot but I cannot get my usb to serial converter to work.

Do you own a spectrometer to see if it shifted more into the red?

midias · Mar 14, 2011

mfo said:
Do you own a spectrometer to see if it shifted more into the red?

No I wish I did. Looking at the datasheet it seems temp is the deciding factor so as it does not get warm there may not be much of a shift. To the eye it looked the same and was more orange than my loc. I am gonna experment more soon and post what I learn. Btw 151 ma is about 81 mw

anselm · Mar 18, 2011

midias said:
I am gonna experment more soon and post what I learn.

Bumping for interest.

I've been playing with mine 1st time today, temporarily in an o-like module (they are GREAT
for this purpose), LM317 set at ~105ma.
I like it, it is definitively more 'orangy' than my DX 50mw red pen, side by side.
When focussed to a pinpoint, it even smokes ye ole electric tape!:wave:

Now I'm off to power up the 20mw diode from DJNY.
And then, off inside some host you go.

midias · Mar 18, 2011

anselm said:
Bumping for interest.

I've playing with mine 1st time today, temporarily in an o-like module (they are GREAT
for this purpose), LM317 set at ~105ma.
I like it, it is definitively more 'orangy' than my DX 50mw red pen, side by side.
When focussed to a pinpoint, it even smokes ye ole electric tape!:wave:

Now I'm off to power up the 20mw diode from DJNY.
And then, off inside some host you go.

Still waiting on my new serial to USB converter. I also am going to build another LM317 for higher current because at 150ma it does not even get warm.

RA_pierce · Mar 20, 2011

midias said:
Still waiting on my new serial to USB converter. I also am going to build another LM317 for higher current because at 150ma it does not even get warm.

You are going to kill your diode.
Instead of ruining a rare item, why not just sell it to someone that will make some use of it?

Temperature is not the only concern when you overdrive a diode. For example, if you take a 5mW CD ROM reader diode, it does not get warm at its operating current (~45mA). Hell, even at 200% this, you won't feel any warmth. This does not mean you can push the diode until it gets hot. Eventually the physical structures of the die will give out before you can measure any change in temperature.

Even with a TEC to regulate the temperature, there is a limit to how much energy the tiny semiconductor can handle. The facets of the die will start to degrade and you will end up with a useless "LED."

The wavelength will shift toward red as you increase the current even if you keep it cool. The difference may not be immediately noticeable if you have no other "635nm" for comparison.

Why not appreciate the diode for what it is? If your only concern is power, don't buy a rare diode and destroy it trying to squeeze out every last photon. Trust me, it will only end in premature death.

The value of this diode is NOT that it is ~$30. The value is that the wavelength is 638nm @ 40mW with great beam characteristics.
So what is the point of getting 81mW out of it if it is lasing at 645nm? Why not just buy a 100mW 650nm diode?

midias · Mar 20, 2011

RA_pierce said:
You are going to kill your diode.
Instead of ruining a rare item, why not just sell it to someone that will make some use of it?

Temperature is not the only concern when you overdrive a diode. For example, if you take a 5mW CD ROM reader diode, it does not get warm at its operating current (~45mA). Hell, even at 200% this, you won't feel any warmth. This does not mean you can push the diode until it gets hot. Eventually the physical structures of the die will give out before you can measure any change in temperature.

Even with a TEC to regulate the temperature, there is a limit to how much energy the tiny semiconductor can handle. The facets of the die will start to degrade and you will end up with a useless "LED."

The wavelength will shift toward red as you increase the current even if you keep it cool. The difference may not be immediately noticeable if you have no other "635nm" for comparison.

Why not appreciate the diode for what it is? If your only concern is power, don't buy a rare diode and destroy it trying to squeeze out every last photon. Trust me, it will only end in premature death.

The value of this diode is NOT that it is ~$30. The value is that the wavelength is 638nm @ 40mW with great beam characteristics.
So what is the point of getting 81mW out of it if it is lasing at 645nm? Why not just buy a 100mW 650nm diode?

I understand what you are saying I have 2 and I wanted to play with one and keep the other at a safe range that is what I am doing. I want to map out a mw to ma curve and I plan on doing just that. Yes I am going 20ma over the rated max but that is my choice.

RA_pierce · Mar 20, 2011

midias said:
I understand what you are saying I have 2 and I wanted to play with one and keep the other at a safe range that is what I am doing. I want to map out a mw to ma curve and I plan on doing just that. Yes I am going 20ma over the rated max but that is my choice.

Sure, but I don't see a reason for it.
The power rating is already known and plotting above that rating is... pointless.
IMO.

anselm · Mar 20, 2011

Would the lasing threshold current be any indicator for the particular diode's efficiency
and maximum current?
The specsheet is quite interesting, with all the graphs.
Does anyone know what "differential efficiency (mW/mA)" means?:thinking:

40mW Sanyo 635nm LDs on Ebay

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