Galileo + 40mW 638nm Sanyo diode

I'm not really sure if this should go in this section. It's more or less a review of the diode, so here it is.

All images are thumbnails. Click for full size.


I chose to install this diode in a spare Galileo host I had. It was a perfect host for this diode. It is compact but has enough mass to keep a diode cool. This red diode does not run hot like the LOC diodes but I figured it is best to keep this diode cool, since the wavelength is shorter with lower temp. The Galileo is constructed of aluminum, so it is very efficient at moving heat and it is lightweight.



I already had this host, driver, and a module ready for a diode, so assembly was quick and easy.
In case you can't tell, the Aixiz module is "trimmed" to 11mm diameter and pressed into a brass slug that threads into the Galileo's "head."

Details of this diode can be found here: http://laserpointerforums.com/f50/40mw-sanyo-635nm-lds-ebay-58430.html

I tested this diode a little bit just in case some others might want to know more about it.
Here is what I recorded for this diode:

42mA - 5mW (not lasing)
60mA - 7mW (threshold)
97mA - 40mW
120mA - 55mW

Test was done with Aixiz acrylic.
It might be worth mentioning that a 650-G-1 gave me only about 5mW more. I am currently using a 650nm Aixiz glass but the power is the same as acrylic.
It's not a lot of data but I didn't think more was necessary.

I played around with the diode at a few different power levels and I can say that there is definitely a small difference in the wavelength when running it at higher current. This is not a diode you want to overdrive. Sure you may get 60-70mW if you push it but the wavelength shifts toward red as it gets hotter or as you increase the current, which defeats the purpose of purchasing a rare wavelength diode.


From left to right: 9mW ~650nm, 9mW ~640nm, 40mW 638nm, 300mW 655nm.
The ~640nm pointer used to be closer to 635nm but I swapped out the diode for a longer wavelength one.


Here it is compared to 11mW 589nm and 40mW 532nm.



At 40mW, the brightness is about half that of 300mW 655nm.
The difference in color is distinct enough. It would be really handy to have a spectrometer, though.
I really like this diode and think it is perfect in the Galileo host.
If you want to see some more of my photos, go here: http://laserpointerforums.com/f48/awesome-laser-pics-40mw-638nm-pics-added-58916.html#post832458

Which driver are you using with it?

Peace,
dave

I knew I was forgetting to mention something.

I am using a driver that used to be part of a 635nm 5mW module. Not sure who made it (possibly Aixiz?). I discovered it can give up to 128mA and is made for case positive diodes. I'm glad I saved it.

RA_pierce said:

I knew I was forgetting to mention something.

I am using a driver that used to be part of a 635nm 5mW module. Not sure who made it (possibly Aixiz?). I discovered it can give up to 128mA and is made for case positive diodes. I'm glad I saved it.

Click to expand...

Sweet!

Peace,
dave

I saw this on the other thread too, Very Very Nice!

Makes me wish I had appreciated 635nm when these came out.

Great looking build.

-Trevor

I'm guessing you used a super long exposure for that last shot, but I must ask anyway. What's the beam like?

RA_pierce said:

I knew I was forgetting to mention something.

I am using a driver that used to be part of a 635nm 5mW module. Not sure who made it (possibly Aixiz?). I discovered it can give up to 128mA and is made for case positive diodes. I'm glad I saved it.

Click to expand...

I had talked with Chuck with Aixiz about this driver
http://aixiz.com/store/product_info.php?products_id=208
and he said it should work with these diodes. Does yours look like that? I had originally asked him what he uses in his 60mW IR modules.

http://aixiz.com/store/product_info.php?products_id=208

DTR said:

I had talked with Chuck with Aixiz about this driver
http://aixiz.com/store/product_info.php?products_id=208
and he said it should work with these diodes. Does yours look like that? I had originally asked him what he uses in his 60mW IR modules.

http://aixiz.com/store/product_info.php?products_id=208

Click to expand...

No. They are small linear drivers and run on 3V. If I remember I will take a picture of it.

Those are the same drivers that are used in the "dildas," are they not?

mfo said:

I'm guessing you used a super long exposure for that last shot, but I must ask anyway. What's the beam like?

Click to expand...

Well, kinda. But only because I was shooting at low ISO to reduce noise.
f8, 20 sec. @ ISO400

The beam is okay. I didn't expect anything spectacular, though. I believe I mentioned it is about half as bright as 300mW of 655nm. That is still pretty bright considering the fact that the 655nm is about 7 times the power of the 635nm. The beam is pretty dim without some humidity.
I just picked it up with my GLP-589. The GLP appears equally bright when it peaks (13mW). 638nm and 589nm are great colors side by side.

RA_pierce said:

No. They are small linear drivers and run on 3V. If I remember I will take a picture of it.

Those are the same drivers that are used in the "dildas," are they not?

Click to expand...

I don't know about the "dildas" but I specifically looking for a driver that would provide the right current and was regulated via the negative side because I want to use an Ehgemus 14650 host with a direct press head in a case positive setup and isolating the diode is not realistic. I actually did not read the thread until I got my diode and I preceded to press it in the head then headed over to the thread to get an idea what current to set it to with my flexdrive and quickly realized this diode was case positive. So I put the build on hold till I found a good driver for it.:undecided: Then I remembered a unit that I had set up that had a IR module from Aixiz and I emailed Chuck to see what driver they were using.

I gotcha.
Well, I think a driver from a 5mW greenie should work if it can be turned down to <120mA. 808nm pumps operate in the same voltage range and are case positive.

That was the line of thinking I had. Anyway the drivers I linked to showed up today and I should be able to test them tonight. I will report back with my findings

op:

Peace,
dave

Great news. And sorry if this is somewhat of a threadjack RA. Finding good drivers for these diodes that can regulate via the negative side so we don't have to worry about isolating the diode is great.

All indications are good. I have the positive from my bench supply hooked up straight to the positive lead on the test load and a wire running back from that connection to the driver positive output and the TTL pad for a always wired on. So basically the positive side is completely bypassing the driver. Then the negative from the bench to the driver negative input and the driver negative output to the test load negative lead. The driver positive input is not used. I turned it on and I got 123mA turned the pot a little and got 143mA.






I think I will stay around 110mA for now. Not a bad option for $3 a driver. Here is the link again. http://aixiz.com/store/product_info.php?products_id=208
Looks like Chuck has come through again.:beer: