White Cree(WG/WC) turned warm white

[rizky_p]

I was soldering a driver into flashlight pill, my solder doesnt have enough heat to heat up the pill to have the solder flow nice and clean. To make things simple i use a small gas torch to heat the pill where the solder need to flow. Unfortunately i forgot that the LED is still attached and get heated up as you can see by looking at the dome there are some kine of crack or gas bubble inside, i thought this LED is toast :candle: but i try it anyway. Holy smoke it turned into Warm white Cree(was probably WG/WC), as warm as Rebel 100 tint in my L2D-RB100 which i really like. Thanks god it doesnt turn green, purple or blue

Forgive the messy flux around the dome

Thanks.

 

[Jarl]

Interesting. I suspect with use a dark brown spot will appear on the die and output will drop, as that's what happened to a severely under-heatsinked KD light I had.

 

[TexLite]

What your seeing is the silicone interface being disturbed between the dome an die substrate,(IE:separation).

The silicone interface is used to cut down reflection/loss between the die and Cree lens,a disturbance of that degree will cut down on luminous flux,but probably not enough to be detected with the human eye.

The ring of the Cree is more robust compared to the dome,improper heat during soldering/reflow,excessive movement,or being stored in an environment with too high humidity prior to being soldered/placed into service will cause this to happen under the dome.

I'm careful with the ring,but I avoid that dome like the plague.

I am unsure why this would cause tint shift alone,perhaps the high heat caused the separation and a browning/distress of the phospher,shifting the tint.I would think these together would have a high probability of having that result.

Thanks,
Michael

 

[Nake]

I had that happen to me when reflow soldering. The output showed about a 20% decrease using a lightbox to measure, no color shift though.