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445nm Heat Sink Requirements

LarryDFW

LarryDFW

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These high-power 445nm laser diodes require substantial heat sinks to operate @ 500 ma and higher.

This is the heat sink design on my new 445nm build:
finhx.jpg

The top cap tightens down on the aluminum disc and finned heat sink.
It has 2.5 oz. of finned aluminum in good thermal contact with the diode.
I think it can handle the full output of this diode.

It must dissipate about 1.5 watts of power @ 500ma,
and about 3 watts of heat @ 1 amp.

I plan on doing some temperature measurements with my IR thermometer at various power levels to verify the temperature rise of the diode.

I think this host has a nice appearance.

The power is provided by a 2600mah Samsung Li-Ion with a single resistor direct-drive.

LarryDFW
 
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how are you calculating the heat dissipation? Have you made the heatsink yet? That looks pretty nice too.
 
designedfor1;

The power input @ 1 amp is 4.2 Volts * 1 amp = 4.2 Watts.

The laser power output is ~ 1.1 Watt.

That leaves ~3 Watts of heat to dissipate to keep the diode at a reasonable temperature.

LarryDFW
 
I'm running an old 18650 driver on my portable. I'm only getting about 300 mW using that simple driver circuit because of switch and connection losses.
OH, I added more aluminum mass to my heat sink ass'y today. They do get really warm at 1 Amp.
HMike
 
@Larry
How do you know your heatsink is going to dissipate that amount of heat? Just a guesstimate or actual test?
 
With DX "temporarily sold out" mean they ain't coming back.

Backordered mean they will get some in.
 
Damn...The Silver, Gold, And black models are gone then :( They seem so nice! The only ones with heatsinks on the actual head :( Besides the $111 one posted at top...
 
jbtm;

The contact between the diode and the outer body is usually poor.

I've had to wrap stranded copper on some of them just to make contact.

designedfor1,

I've built a few hundred UV flashlights with 3 watt and 5 watt LED's for practice.

It has 2.5 oz. of finned aluminum in good thermal contact with the diode.
Click to expand...

LarryDFW
 
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I made a portable with a cheap c-cell flashlight, and screwed the axiz module head into a disk of aluminum and then to the flashlight, it gets warm after running for a few minutes but not hot. The power is 600mw at the diode.

The diodes need VERY substantial heat sinking if running at a full watt, as in a 3x2x7 aluminum project box gets quite warm after 15 minutes of use. The bright side is these diodes were meant to run hot in the projector so a little heat isn't an issue.

The bottom line is the axiz module or even the nicer black modules are NOWHERE CLOSE to enough heat sinking by itself!
 
Howdy Larry Here is my first 445 I picked a host that would let me get two 18650 end to end so 8.40 volts with plenty of current.
I built my own linear driver for this diode and strapped the regulator to the back of the heatsink ;) I am feeding it 630ma and with a LarryDFW lens it's putting out 547mW :)
With this HS I could take it all the way though :D I think this would be good to offer in a kit :)
28i3sci.jpg
 
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