Perhaps this: D-c-fix diffusion film
I think it’s terminal.
Yea it looks like a honeycomb TIR or dc fix is the only answer I can find.
Agree with the other comments. The phosphor is chipped off and cannot be repaired, so the only solution is to make the secondary optic more diffusive and hope to blend the beam and even it out.
Just be warned that it can get worse over time when using high output.
This.
From the bluish cast in the beam pattern it is clear the damage involves a bit of phosphor that came off the led. That isn’t repairable.
I’d recommend either living with it or replacing the LED with an intact one.
Didn’t someone once try to “repair” a phosphor-stripped led by making a mix of some phosphor scraped off some LEDs and high temp epoxy and slathering that on the bare chip?
I vaguely remember people doing this. It “works” in the sense that it can make a phosphor-less blue die produce white light again, but the beam quality and output are probably massively compromised, together with power handling. Not to mention the effort and access to the tools–it is more sensible to just get a new LED in this case.
Were this just about any other LED I wouldn’t have even asked this question at all but unfortunately the SFT40 4K is unobtanium and I am willing to go to a lot more lengths (and some cost) to make it not die. It was in a FW21 XL9 and was transferred to an S2 with a honeycomb TIR. It looks more than acceptable in that setup and makes the loss of it worse knowing it will die. So it was worth a shot and if anyone would know it would here.
I see. Best option for the moment is probably to just do nothing and diffuse the secondary optic. It’s a piece of missing phosphor, not a burn spot or anything and should not go into cascading failure. Performing any modification of the phosphor carries a huge risk.
Perhaps you could fill the “hole” with some clear epoxy which is made for the temperature range the LED works at. This could protect the side of the phosphor a bit but it could also make the artefacts worse.
I would caution against doing this until you’ve tried it on a spare LED–the epoxy seeping into the phosphor will change the refractive properties of the phosphor layer and thus the color of the light emitted. There could also be thermal stress issues that could weaken the phosphor.