And that last lens is indeed interesting. Though it sacrifices some frontal area. And need a windown in the front to get waterproofing (which reduces efficiency by enother 1% or so). Too bad the paper doesn’t describe it better….
Wow, thanks for the link.
I remember seeing LL datasheets before but never got interested in their lenses. But they seem to have many ultra-compact lenses available:
https://www.ledlink-optics.com/wp-content/uploads/2018/05/2018-Commercial-Lighting.pdf
For example:
LL01CR-CTKxxL02-P is 49.5 x 7.8 mm designed to produce narrow (10 degree) beam with 3535 LEDs. Can’t find a datasheet for it though.
21700 thrower with 52 mm head and 100 mm length?
Or V-Cut LL01CR-DAWxxL52, smooth beam thrower lens (how does it compare to OP?), 45 x 10.85 mm.
Looking for a source for lens type optics for large COBs (over 22mm dia. LES). Aside from reflectors, everything I see is for 19mm and under.
@Agro
You have to replace “xx” in the part number with the angle, in this case 10, then you (or google) will find it —> https://www.ledlink-optics.com/upload/product2led_light/23_120180531033432.pdf
You can have a look at the LPI patents if you want the gory details. Or this, it’s a bit easier to read. I have also found their book “Nonimaging Optics”, very interesting but so complex that I can’t even scratch the surface.
Looks like these things were a bit of a byproduct of researching solar concentrators for multi-junction cells.
I’ve always been partial to Ledil lenses since they had numerous choices for 35mm optics for single or multiple LEDs. The Cute-3 S and GT4-XP-S paired nicely with 32mm triple and quad mcocb’s.
Or soda can thrower with 52 mm head and 90 mm length? 
I tried that but failed to find anything. Thanks!
Key takeaways:
- LED opening is 7.54 mm so basically any LED, even XHP70.2 should fit (XHP70.2 diagonal is larger but only the dome enters the lens cavity).
- The bottom is patterned, so it’s not a pure throw design, they do some beam mixing as well
- That’s a Fresnel TIR at a portion of the bottom
- Flat round front, nothing that would make mounting harder
- They list it as high efficiency but fail to provide any efficiency numbers (except for the raw plastic that they use (polycarbonate))
- Performance is specified only for some COB so I won’t predict how well it collimates.
- Beam shape: spot with barely any spill. Looks very good to me.
I’ve seen that pdf before. But not the book. $20 for a pdf. With such non-recommendation I’ll skip it for now but maybe one day….
LedLink:
LL01ED-ASAxxL06-P, LL01CT-APGxxL06-M2 are up to 26.5
LL01ED-ABXxxL06, LL01CR-BAYxxL06 are up to 24.2
I intended to write about Fresnelized TIRs for a while…
A simple TIR lens guides light on 2 paths:
The light emitted forward is refracted as it enters the lens and again as it leaves it.
The light emitted sideways is refracted, TIR-reflected and refracted again.
It is possible to fold one or more surfaces to reduce height. Some call this TIR-R, some Fresnel-TIRs.
Here’s a one-time folded Kingbrite KB-H43-3-XP
Four-time folded Ilenstech ILENS508-COB90-10-H
You don’t have to fold the sides, you can fold the front instead like Ilenstech ILENS576-COB69-12-H
Or you can fold the back like Darkoo DK4304-XP-G
Here’s a good paper that generalizes the concept:
https://www.orafol.com/tl_files/EnergyUSA/papers/LED-Source-Modeling-for-Optical-Design-workbook_Davis_2004.pdf
And some more papers / articles:
Note that Ledil makes Fresnel TIRs too:
https://www.ledil.com/product-landing/single-lenses/OLIVIA/
I think I’ve seen some Led Lenser that had the outer front folded though I can’t find it now.
Thanks… that’ll work for one, though still liking for something for over 30mm dia. COB…
This one is up to 30 mm:
Yes, great… though I don’t have a need for 200 (MOQ)… trying to find a distributor stateside, hopefully…
You can contact them. Maybe they’ll sell fewer.
Louie, not sure if that’s interesting for you but there’s also Ledil Stella - a silicone lens family for 30 mm LES. Over 30 mm I also see only reflectors.
I dis find a seller on Alibaba that has 30mm glass COB TIRs and aluminum housing… Will check out those LEDIL lenses too…
Interesting diffuser in a small Verbatim bulb. This sits on a small Cree CXA COB. Old & inefficient (65lm/W), but it was only 1.40 so I bought it.
I’ll have to take pictures but it’s a very nice and even “beam”. Now if there’s a way to fit something like this on top of a 1” flashlight…
This is one of the biggest TIRs, 75mm
It’s only been tested with COBs up to 23mm but the LED opening seems much bigger than that.
Only problem is that when using a TIR with a large LES LED then the angle of incidence varies a lot, which may cause light leakage since total internal reflection only works at large incidence angles.
Auer makes a 110mm hybrid reflector but only takes max 9mm dia. COB.
I found a manufacturer on Alibaba that makes 100mm TIRs for COBs up to 30mm in 10, 15, and 30 deg. FWHM.
Khatod Cosmo is another family of lenses that employs Fresnel TIRs.
There’s one zoomie construction that I haven’t seen on a flashlight yet but found 3 lens makers that do it:
Moving lenslet array based.
Near the LED there’s a fixed TIR. The TIR has a lenslet array at the front face.
In front of the TIR there’s another lens. Its back is the exact negative of the TIR’s lenslet array; the front may be flat or refract the light in other ways.
When both lenses are very close (pretty much touching each other) - the lenslet array doesn’t do much, it’s almost like a regular TIR.
When they move out - the beam gets wider.
Pros:
- fair efficiency, TIR capctures all the LED light
- no need to put LED on a pole
- easy to do fair waterproofing: seal at the TIR. Beam will be bad under water but submersion won’t cause damage.
- short zooming movement
Cons:
- current implementations don’t have AR coating which hurts efficiency
- lenses need to be well aligned
- can throw OK but never as well as a single TIR
Makers: