Heated 445 diodes

[dnar]

Just curious, how hot have you guys run your 445 diodes?

Last night I setup a test with 2 x 445nm modules running 500mW (half power). Module 1 was tec cooled to 10c, the other tec maintained at 40c. The wavelength difference was noticeable with the 40c module appearing much brighter and a nicer blue hue.

I know these diodes are rated for 30c operating temperature, but at 500mW I am wondering how long they will last at 40c? In fact, I wonder how hot the actual die is when the mount is 40c?

I am contemplating running the 445nm hot (warm) in my RGB build to obtain a longer wavelength.

Brain fodder.

[danielbriggs]

They run much hotter than 40deg in the projectors.

[dnar]

They run much hotter than 40deg in the projectors.

I thought so, but they are not CW or are they?

I have a spare diode, I wonder if I should do a little torture test....

[danielbriggs]

Could be talking out of my arse here:
I seem to have the figures, 70% duty cycle, 1.4A in the corner of my head...

[dnar]

Could be talking out of my arse here:
I seem to have the figures, 70% duty cycle, 1.4A in the corner of my head...

Hmmm. Sounds promising. Has anyone actually measured the normal running temps of these diodes in a projector?

I feel much safer pushing the temps at 500mW CW now. More info will provide more confidence to raise the temps.

Cheers mate.

[edison]

I have a quad blue doing 4 watt. But that,s only for 20 sec Then power drops because of the heat. I could push them harder but that will produce more heat. I have ordered 40x40 peltiers of 68 watts too keep it at 23 degrees. I will do a test to keep them stable at 40 degrees. I think they could do 800mw but i think that,s about it

[dnar]

I have a quad blue doing 4 watt. But that,s only for 20 sec Then power drops because of the heat. I could push them harder but that will produce more heat. I have ordered 40x40 peltiers of 68 watts too keep it at 23 degrees. I will do a test to keep them stable at 40 degrees. I think they could do 800mw but i think that,s about it

Cool, I mean warm.

For me I have power to burn, as I am not running anywhere near 1W, so for me it's about wavelength shift.

Keen to see your results.

[hobbybob]

Is it possible for someone to measure the wavelength shift per degree ?
I know for reds it's 0,3nm per degree celsius you make it cooler.
If this is the same and you "heat" or stabilize the cooling at for instance 40 or 50 degrees instead of running it 25 degrees that you get like 25x0,3nm shift upwards, so from 445 to 452 nm ? That would be ... eh... cool !

I thought i also read somewhere if you heat electronic components 10 degrees celsius it's lifespan is halved. If a diode normally does 10.000 hours then it does 5000. Still nice.

[logsquared]

I have a quad blue doing 4 watt. But that,s only for 20 sec Then power drops because of the heat. I could push them harder but that will produce more heat. I have ordered 40x40 peltiers of 68 watts too keep it at 23 degrees. I will do a test to keep them stable at 40 degrees. I think they could do 800mw but i think that,s about it

Sounds like you may not be removing enough heat from the diode can. I had this problem with the o-like modules. It's real easy to check. Using a large ballast resistor and voltage source set the current at 1amp or so per diode. Measure the current. If it starts to drop rapidly you may not have high enough thermal conductivity between the diode can and the mount.

[edison]

Thanks losquared. I will check that. I didn,t have the problem with the red diodes tho and when i used 3 peltiers of 20x20 in series that wasn,t enough either. With 4 open cans and 2 20x20 peltiers running them at 1.5 amps that was enough. I will check but also will try a 40x40 peltier on my die4chill. I have also a 30x30 at 8.5v doing 38 watts so i hope that,s the one that can cool the 4 watt. Its so great to see when you have a setup of 950mw and is rock stable!!!!!