Hey folfs !
I am looking to cool a COB LED. This is a "bicolor" COB (kelvins may vary). See attached file. The COB is composed of a 200w warm white and a 200w cold white. I would like to use these 2 colors up to 150 w each. A total of 300w. I beleived the LED is for a total of 200w, but the seller said me it 200w for each color.
My problem is that the LED is large (diameter 58mm), too large for a CPU heatsink (whose cooling surface may be a square of 40mmx40mm). I wonder if by installing the LED on a heatsink of this type, the edges of the LED which will not be in contact with the heatsink will overheat. If so, I wonder what trick to find. Can I attach a larger copper plate to the heatsink to attach the LED or will this be counterproductive?

 

image shows that 58mm is just the lens diameter, product diameter is 68mm.
i would use copper plate and braze copper coil to it, then use liquid cooling.

 

or something like this
https://www.globalsources.com/Heatsink/Heat-sink-1184838167p.htm

this one is designed for high power LEDs and seem to match your product:

 

Wow, thanks a lot for this answer!
Actually heatsink designed for high power LEDs like you linked me are available on website with a huge minimum order. I can't find for 1 or 2 units on Aliexpress for exemple. I think I will do your idea with copper coil. Thanks a lot!

 

Digikey lists many heatsinks fir COB LEDs. The first one I looked at had models up to 130 mm diameter.