Confused about SureFire TIR optics.

I have a later model SF L1 that supposedly has a TIR optic. It looks like a regular reflector in there to me? I remember the older E1L and E2L lights had a weird bubbly lens in the front, was that the TIR? Also what does the TIR do that a regular reflector doesn't (I have read tighter beam, but how?). I will gladly read a thread on this but I searched and couldn't find one. Thanks.

When I 1st looked at my E1B (same optic as L1) I thought the same thing.............it's a reflector! But look at it from a 45' angle and you can see the black inside of the head where a reflector should be. I don't know HOW they do it but optics are supposed to be more efficient, in other words more of the available light from the emitter makes it out onto the target. I think you can get optics in many beam angles but they are pretty much mostly hotspot and little spill compared to reflectors. I think SF did a great job on this latest TIR as it finally has enough spill (even on low) for even close up tasks. :twothumbs

4EN[sic] said:

I have a later model SF L1 that supposedly has a TIR optic. It looks like a regular reflector in there to me? I remember the older E1L and E2L lights had a weird bubbly lens in the front, was that the TIR? Also what does the TIR do that a regular reflector doesn't (I have read tighter beam, but how?). I will gladly read a thread on this but I searched and couldn't find one. Thanks.

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Guys who know more than me will be on soon, but I would reposond by saying that it sounds like you have the newest L1 Cree- assuming that your light isn't older than my luxeon L1 purchased years ago.

This new light has a TIR optic, but it doesn't have the crazy "bubble" appearance of the older models. The TIR focuses the light in a way that the reflector isn't able to with an led. The beam it creates is very tight, (at least in this case- i've heard that there are optics on the wide Malkoff drop ins- but again, this stuff is out of my league-) and on the newer cree model L1, also seems to give very usable sidespill. (Although many folks here, including me, like even more than it produces- but it is still a good trade-off, because the throw is amazing.

The new optic also did away with the square beam of the old model.

OK- I will let the guys who know a lot more than I do give you the details!

Thanks for the insight. It still looks like a reflector although I will take your word for it that it isn't. Oh, it is the newer cree model by the way.

So is it kind of like a projector lens?

4EN[sic] said:

So is it kind of like a projector lens?

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No, a TIR optic bounces light off of its back surface and then out of the light. A normal lens just passes light through itself.

4EN[sic] said:

Thanks for the insight. It still looks like a reflector although I will take your word for it that it isn't. Oh, it is the newer cree model by the way.

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Part of the reason it looks like a reflector is that it is actually shaped more like a reflector. If you see one from a disassembled light, it's kind of cone-shaped with the narrower tip of the cone closest to the emitter, much like a reflector would be.

If you look into the lens and tilt it very slowly in different directions, it will be easier to see the differences in the way it bends light.

http://candlepowerforums.com/vb/showthread.php?t=186771

^^ That thread has some great pictures of the inside of a KX2. The newest KX1, KX2, E1B and E2DL should look identical to that. However, I'm not sure if the optic in the L1 would be the same as that...

To find out how TIR optics work, Google is your friend

It looks like a reflector because it is a reflector and it is reflecting. It is a clear optical element.

A TIR is referencing the optical phenomenon known as Total Internal Reflection. A TIR optic is not totally reflective it just uses the principal. Too detailed to explain all of it here but I'll mention that it uses the envelope of air surrounding the outside of the conical part of the optic. You can see TIR for yourself if you have an aquarium. Angle your view so that you can see objects in the tank reflected on the side walls. Now touch your hand to the outside of the tank where you see reflections. You will see your fingertips instead of the reflection because you have removed the atmosphere from the surface. Here is a simple explanation with more detail.

Here is an example of TIR:


Here is one example of a TIR reflector Al posted a while back:

Photo by Shelby Chan aka CPF member, AluminumOvercast

That "picture is worth a thousand words" saying comes to mind. That pic of the clear TIR helped me out. Thanks for all the answers.

That photo of the TIR optic was taken by Shelby Chan

Thanks, Al. I was thinking it was his and that I needed to give credit. I meant to do an edit but didn't make it back to this thread until just now when I saw it pop on User CP. I'm pretty sure you posted it at my request a long time ago. I always want to do my part in contributing to a pleasant environment for Shelby. It's good of him to post any photos at all on CPF.

My post has been edited.

cool