That’s what I thought…but then I couldn’t find anything but COBs under acrich name.
Thank you thijsco19!
Could be either a clear or matte dome… or a fresnel + reflector setup, that’s where I’d bet my money.
With the central dome being hollow, it can’t be (single-surface) refraction towards the reflector.
Doing some searches I stumbled upon interesting quote:
Any pictures of BD headlamp lenses? 
Aaaah now that makes sense! :person_facepalming: :person_facepalming:
Look what else I found… SORAA has been at this for a while (this is from 2015 or even earlier):
I see the MR16 or GU10 spots (50mm) go for 40€ apiece on Amazon, but on ebay a few pop up for 10-15GBP (+shipping 
)
Is that Yajiamei lens RXI as well?
https://www.aliexpress.com/store/product/COB-LED-lens-diameter-69MM-12-degrees-CREE-CXA-Condenser-lens-Plastic-plating-reflection-lens/209770_32639660451.html
It doesn’t look like RXI but it’s flat and narrow.
Note: there are variants from 50 to 75 mm.
Description says optical grade PC……
RXI is just fine with PC. It’s all about folding optical path. Light goes up and is reflected (by TIR or metalization) down towards the bottom and towards the sides. Then the main reflector directs it forwards.
Refraction as the light enters and leaves the lens is usually used as well.
A while back I remember a camera “lens” that was relatively flat ike Carclo’s catadioptric but used multiple folds…
BTW every time I see that flat 50 mm optics I can’t help by wonder:
BLF Q8 has 4 domed XP-L.
XHP70 has 4 XP-L dies under a single dome.
How would the beam of Q8 compare to XHP70 under a flat optics?
Similar LED config.
Similar size, most XHP70 lights tend to have long heads but this one wouldn’t. Actually it would be shorter.
The flowery spill wouldn’t be there.
Those flat lenses don’t tend to be as narrow as possible. Would they have a donut hole?
Assuming a lens is wide enough to eliminate the donut - what would throw better? Q8 loses some frontal area due to being a quad. Lens needs to compensate for the donut.
Thoughts?
Guangdong Hengzheng hexagon seems nice.
Very low height due to fresnelized TIR. And packaging efficiency is very good. A 7-up would have about 40 mm diameter. 19-up would be about 66 mm.
Too bad there are no throwier versions. It significantly reduces the benefit of packing them tight.
The lenses from Polymer Optics are hexagonal also, allowing for tight packing. They also come in narrow spot (LED dependent).
Weird, just weird.
12-30° from <9mm COBs?
I’d like to see one of these in action… TIR RLT collar ?
That doesn’t look like a collar but rather a pre-collimator.
Ah, I see what you mean. I was distracted by the aperture stem between the two elements.
Still scratching my head a bit…
Thinking more about that lens. It’s interesting.
- cheap way of doing pre-collimation
- the centre of the front lens must have different focal length the the rest - because light goes there through the channel, w/out 2 intermediate reflections
- light that goes right next to the channel gets refracted
- some (not much) will hit the channel side and TIR from it, then enter the second lens at off ang
- some will enter the lens and join the light that passed the channel - but it was refracted and travels at different angle
- you’re going to get a few artifacts with it
- typically frosted aspheric lenses have frosting on the first surface. This has at the last so it can remove those artifacts
- light that goes right next to the channel gets refracted
- would like to see it tried
I wouldn’t expect too much innovation from a brand like Trustfire, but it looks to me that they introduced RXI-style lens to AAA sized lights.
https://www.aliexpress.com/item/4000080687843.html
I’m impressed!
ADDED: it actually may be the same lens as the one they use f.e. in MINI3:
Interesting light. I might get one to put in an E21A with 10mm virence board
There’s something going on with Trustfire MC1 as well.
Fresnelized TIR? Or maybe regular Fresnel?