Custom Build Advice (UV LED with Plastic Host)

[QReciprocity42 (efficacy ≠ efficiency)]

@BudgetSteve

is power handling the efficiency or something else? Is it an issue at 700mA or below? or is it more relevant if you want to overdrive?

I have an air vent which moves a small amount of air across the mcpcb and reflector to the outside of the device.

Are you aware of any tests on this forum comparing aluminium to copper? I read that copper reduces hotspots on the board itself when compared to aluminium but that’s all I’ve found so far.

My apologies for being unclear with terminology! By power handling I mean how much power it can take before output levels out and falls. Larger emitters (larger emitting surface and larger footprint) have better power handling, and emitters with better power handling are also more efficient given the same drive power.

Better power handling certainly benefits overdrive, and one should consider running the LED at the rated power without adequate heatsinking a form of overdrive.

There are some old Al vs Cu MCPCB tests here. Since UV emitters are less robust than white, the difference is likely to be more pronounced.

@BudgetSteve

I will look into it but my budget is limited, so I may not be able to afford an emitter that costs more than the Seoul. (buying in bulk, 1000+ units)

Understood! I somehow missed that you are getting emitters in bulk, in which case even small cost differences matter.

@BudgetSteve

at the moment no, but if I were to have the mcpcb customised I could leave some metal exposed on the front of the board and maybe use thermal paste between the board and the reflector?

I still see 2 potential issues:

1. Exposed metal might lead to the + and - terminals of the LED shorting on the reflector.

2. Thermal paste is a liquid that becomes less viscous at higher temperatures. It is likely to flow into the reflector and destroy its surface during operation.

I would still suggest implementing a metal thermal path from the MCPCB to the exterior of the device.