EDIT [10/14/2017] : Link to the experiences with XPL-HI and TIR lenses
I decided to play with some TIR lenses I have and my Convoy S2+ XML2 U2-1A.
This is not a well structured thread and please do not expect scientific results or measurements, as I don’t have them.
But, maybe this can help some members to go “TIR”d in their flashlights and make some experiences ^:)
And maybe it helps people to not make the same mistakes I did :FACEPALM:
Frosted center, 15º angle (maybe)
This was as lens from a SSteel flashlight I bought and modded. I didn’t liked it in that flashlight, but on the S2+ is not completely bad. It has a narrow beam, hot hotspot and a small spill (compared with a reflector or with other lenses)
Due to its dimmensions and characteristics, it was not necessary to use a holder. It also has a “tube” on its bottom that fits the LED chip inside.
The pebbled (hive) lens, one of my favourites on this light and, on smaller versions, for XPG3 and Nichia (Amutorch AA lights I recently modded). Has a wide homogeneous beam, good to indoor and close range illumination, and maybe good for some headlamps!
A holder (cut in some parts) had to be used to help placing the LED in its place, well centred. The holder, with this lens, does not interfere much in the reflection.
Well, I just noticed later, but this lens was a bit damaged in the bottom, in the LED hole. It can be noticed in the photo.
Despite that, this lens, that does have the adequate measure in diameter, had to be used with the S2+ glass lens. Why? Because it is shorter, so when it was placed there as a gap between the lens and the bezel. On these pictures it had no holder, and that made the centering process a bit difficult.
That, the proximity between the lens and the LED, and the lens characteristics (center with 60º angle) originates the square beam that is seen. Also, with these kind of lenses (“clear” surface, +45º…) small scratches in the lens or in the LED tend to appear in the beam!
Not funny…especially for a messy guy like me that does not treat flashlights well :FACEPALM:
This is the same lens as before (3rd) but with a white holder that doesn’t perfectly fit on the bottom of the lens and the LED. It creates a “zoomed” beam, showing the LED shape, because of the gap between the emitter and the lens.
Yes, I could have cut another holder and adapt it to the lens diameter, but I was a bit busy and just wanted to make some experiences. The good and the bad ones }D
Frosted lens! It is a bit similar to the pebbled one but my impression is that it allows to pass more light, in a wider beam, also with no hotspot. It is also good for indoor illumination as it provides homogeneous light around. It may be used to walk for a short range illumination.
I guess this kind of lens will work better in a XML2 T6-4C or other LEDs with Warm White characteristics.
Similar to the 3rd and 4th experiences, but this has a different angle and different dimensions. I couldn’t use it with the holder, just with the glass lens above it. It has a larger hole for the LED and that allows a slightly better beam (compared with the 3rd and 4th). However, my guess is that if I used a holder, the beam would be more round and less square, because the holder fills the space between the bottom of the lens and the emitter.
This kind of lens (45 or 60º, I can remember), with an appropriate holder can be a good option to replace a SMO reflector, as it creates a defined round hotspot and also has some spill. I forgot to take a photo from above :FACEPALM:
This was, perhaps, the most appropriate lens for this light, aside the 1st, the 2nd and the 5th.
I used it with the holder, but as the holder had to be put before scrweing in the pill, I forced it against the driver’s wires. Conclusion, it started making some, the driver spring shrunk and then…it stopped working. Before that, it made that strange blueish beam!
With a well soldered emitter, where the wires do not touch the plastic holder and the holder does not press the wires, this can be a good lens, as it produces a nice beam (maybe 15º angle).
Also, using the holder may help to disguise some of the lens scratches or imperfections.
In lenses that are not frosted, pebbled or with narrow beam, the wires of the LEDs sometimes are visible in the reflection, at least if they are these kind of CREE Leds.
Pressuring too much a holder against the emitter and the wires :FACEPALM:
And that’s all folks. I had a funny time and this error made me re-solder the emitter. I’m also using a retaining ring in the pill, even with a 8x7135 chips driver Happy not to have to solder it this time!
Hope this helps some going “TIR”d!