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High Power RGB

Anthony P

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I have completed a RGB project with a combined output of about 3-4W. It uses the Red ml501p73-p1245, Green NDG7475, and Blue PLTB450B. The dichroics used were from a Russian E-bay seller and turned out to be excellent for the project. All 3 drivers are analog controlled Black Bucks. The red required some additional resistance tweeking on the adjustment pot to limit current range to the red to about 900mA. Normally, a Black Buck has a low end adjustment of 1A.
Cooling is acomplished via 2 40mm TEC modules connected to the 1/4" Al mounting plate. They are contolled by 2 digital thermostats and a 10A switching power supply. The temp probes are mounted inside 2 rolls of Cu on the plate secured with Artic Silver. The hot side of the TECs are heatsinked and fan cooled. The cooling system works perfectly.
Assembly was straightforward with only 2 minor glitches. One, the 12mm copper modules were a sloppy fit in the heatsinks. This was resolved with shims made of copper foil. Two, the collimating lenses (G-8) are a bit loose in the modules so alignment goes off when removing lens caps. This is not a big problem because the kinematic optic mounts allow for very easy adjustment... just a few seconds to align.
I have posted pictures to IMAGUR. The camera really does not do it justice. I tried unsuccessfully to photograph the incredible yellows and even purples it can generate.

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Thanks for checking this out.
 
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paul1598419

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Very nice job. My only concern would be with the red Mits diode. It has a much greater diverging axis than the green and blue diodes do. I would expect it to bleed out a bit especially at a distance.
 

Anthony P

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Very nice job. My only concern would be with the red Mits diode. It has a much greater diverging axis than the green and blue diodes do. I would expect it to bleed out a bit especially at a distance.
You are exactly right, Paul, about the Mits. Also, the red ratio is a bit on the low side for power. If you have a suggestion for a better red I would certainly swap it out.
 

paul1598419

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Unfortunately, I don't. There were some 650nm high power diodes around several years ago, but I haven't seen them available in a long time. All the high power reds now seem to have horrible divergence specs. I might try to use a 6X cyl lens pair with it and BEs with the other two, but that would be more work.
 

logsquared

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Sharp GH0637AA2G has a about half the divergence of the P73. It is only good for 750mW so need to knife edge or PBS two. Probably easier to just overdrive the P73 and add correction optics.
 

Cyparagon

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Since the thermal mass of a temperature probe is nearly nothing, the thermal energy flow to/from a temp probe is also nearly nothing. As such, gluing them in a hole (or perhaps taping them on) will offer about the same performance.
 

CDBEAM777

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Nice Build !!!!...or….COOL BUILD !!!

I agree with LS …... Two (2) Sharp GH0637AA2G diodes...combined with a PBS and a Wave Rotator added!!
You might need to add a secondary Ally plate to increase your working platform....looks like NOT enough room to add much atop
your thermal unit….then....you will have some cooling loss thru the Ally plate to Thermal unit interface. Some Artic Silver there !!

Even those Sharp Red's would likely need a set of Cylindrical lenses to really equal the divergence of your Green and 405.

The lack of higher power Red's continues to plague us !! SO.....we must deal with it. I have used the Sharp GH0637AA2G .

With it....Be mindful of spikes !!! It does NOT like them....and will COD....which really stands for "Crapped Out Diode"
Hahahaha !! The Sharp GH0637AA2G knee is also 900 mA.

Anyway....Good Luck....Thanx for the pics !!!! NICE JOB !!

Remember...YOU ASKED how to get more RED Photons !! Also....dump the LD holders....Go with the ones from Lasertrac…..my current favorite.
BUT....IF you have press fit the NDG7475....well...kinda stuck with the standard 12 x 30 unit. Likely get better thermal transfer with the Lasertrac LD mounts....Maybe good to apply to your RGB II unit !! ( And....there WILL be another...I assure you )

My, my....aren't we a helpful bunch !!!

CDB
 
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