Agreed, hence my skepticism about that particular patent, I don’t see how much light recycling can be achieved with this arrangement, nevermind precisely bouncing it back to individual different coloured LEDs in a multiple array.
But perhaps there is also some secret technique not revealed in the patent itself, which wouldn’t be unusual.
It would be nice if you could show us a ray-trace for the spherical collar, it might help those who have ordered this one and demonstrate your point even more clearly. If you could simulate the light source being a small LED in the middle of the reflector (Lambertian), even better.
PS: I tracked down DrJone’s paper that I remembered, at Flashlight Optics - Dome, Dedoming and Throw
It’s from 2013
(Edit: 2012)
so I daresay there have been plenty of developments since, particularly in phosphor design, domes, and the latest back-illuminated LEDs, but still gives plenty of insight today.
I’m still skeptical about light recycling in general, particularly in modern LEDs where I hope a high proportion of the LED light is absorbed in the phosphor with little wasted, but agree that the collar is still a clever way of scooping up more of the off-axis light and re-directing it in the desired direction.
I’ll be watching this thread with interest, having no experience myself.