Why TIR's in Surefire lights?

I just looked at a Kroma yesterday and was very much not happy with yet another TIR optic on an otherwise awesome light. My HDS EDC60GT with its stock GT Lux III and stock reflector is AMAZING!!! Why can't Surefire do that? Why do they have to use some Total Internal Reflector optic that robs lumens and makes a square thrower with cruddy spill? I just don't get it... If the Kroma had a great reflector, it would be perfect. If Surefire is so great(and I LOVE Surefire Lights and I believe they are), why do they insist on optics when it has been proven by others that a great reflector works much better for most, if not all, applications?

In fact the TIR optic is better able to produce a beam using more of the lumens produced by an LED compared to similar dimension reflector.

What we are experiencing is SureFire's development of the TIR optics into ever better designs. They have come a long way but are not there yet in my opinion.

The K2 Kroma's beam is one of the best I've seen from a TIR.

I believe one of the goals is to produce a "P60" type beam profile from a bezel no larger than the 6P's bezel that includes the electronics and is able to handle the heat.

I believe that SureFire and SAIC are positioning themselves to use their optics technology to take advantage of the increasing variety of LEDs coming to market. In the future I believe optics will be able to deliver beams from shorter, slimmer diameter bezels compared to using reflectors.

Al

Solid State.

It won't collect dust, tarnish, and is held solidly in place so that when dropped the force continues on through to the rest of the light

In my view any kind of optic is about making a light solid state

Size15's said:

In fact the TIR optic is better able to produce a beam using more of the lumens produced by an LED compared to similar dimension reflector.

What we are experiencing is SureFire's development of the TIR optics into ever better designs. They have come a long way but are not there yet in my opinion.

The K2 Kroma's beam is one of the best I've seen from a TIR.

I believe one of the goals is to produce a "P60" type beam profile from a bezel no larger than the 6P's bezel that includes the electronics and is able to handle the heat.

I believe that SureFire and SAIC are positioning themselves to use their optics technology to take advantage of the increasing variety of LEDs coming to market. In the future I believe optics will be able to deliver beams from shorter, slimmer diameter bezels compared to using reflectors.

Al

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Ok, I understand that. The TIR optic technology is still evolving. I just haven't seen much spill from any TIR yet, although I will admit the Kroma does have a reasonable amount of sidespill. Al, you hit the nail right on the head (as usual.) I hope you are right about the P60 type beam theory and your other beliefs as well. I guess I am spoiled on the Surefire beams from their incans and I have to understand and be patient. Sorry if I came across as rude, I just need to have faith in progress and R&D.

I figured it was because they were cheaper to produce.

Josh

IMHO, i think TIR or not is very much a personal preference. The only TIR light I have is the E1L and boy do I love it! I do admit that sometimes it is a little lacking in side spill but the throw factor is awesome when used in the woods (forest here in Singapore).

Don't get me wrong by my answer, I have a KL1 head that I got a while back after someone tried in vain to mod it and destroyed the original board. I got it as a project, custom anodized it and replaced the driver with a BBNG500, planning to sell it. Turned out really nice - brighter than my EDC U60. It didn't sell, and went on the shelf for a while. I recently got it out after playing with a lot of other high-tech ones such as flupics and my EDC U60, and have been using it more and more as a highly efficent pocket rocket with a McR 2 stage cap - it's one of my friends favorate lights that I own.

It really is a personal preference, and the more I use it, the more it grows on me.

Josh

chesterqw said:

TIR optics CAN have 100% efficiency but not all TIR optics can do that.

however neither can reflectors have 100% efficiency most only have around 97%.
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How is this possible? Are you talking very specialty glass with sophisticated A/R coating? Even so, i'd be surprised if you could get above 99%. Most polycarbonate (read: affordable) lenses are in the 85%-95% efficiency, of which *all* the light passes through. A reflector based solution will have maybe 30% of the light hitting the reflector, then passing through the glass, while the other 70% passes only through the glass. Those numbers depend on a lot of design aspects, though.

If you are a volume manufacturer, a custom TIR lens will cost you maybe $0.25 (after you pay for tooling), while a simple high transmissivity glass window with A/R for a reflector can cost you a couple dollars (not to mention the reflective coating you want). If you cheap out on reflector components, your efficiencies are in the low 80%.

From my research, when cost is a definite consideration, the TIR lens wins in efficiency. For a bit more money, a quality reflector design can be more efficient than a budget TIR design. With even more money... well, i haven't had that luxury.

At the end of the day, though, we are only talking about 5-10% efficiency differences, which pretty much nobody will be able to distinguish the brightness between. Cost, packaging, and other issues become much more important.

Can you explain more about your 100% efficiency claim?

Forgive my ignorance... What is a TIR?

Total
Internal
Reflectance

Basically, all the light bounces around inside the TIR thingy until you want it to come out. In the case of a lens, it bounces along the sides of the lens until it hits the front, at which point it theoretically shoots straight out.

I used to work for a company that made hundred foot long tubes using this principle... kind of cool, really.

LMI said:

Total
Internal
Reflectance

Basically, all the light bounces around inside the TIR thingy until you want it to come out. In the case of a lens, it bounces along the sides of the lens until it hits the front, at which point it theoretically shoots straight out.

I used to work for a company that made hundred foot long tubes using this principle... kind of cool, really.

Click to expand...

Thanks.

chesterqw said:

TIR optics CAN have 100% efficiency but not all TIR optics can do that.

however neither can reflectors have 100% efficiency most only have around 97%.
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How is it possible to get 100% efficiency? Even 97% seems excessive.

TIR is also the principle by which light "stays" in a fiber optic.

JnC said:

TIR is also the principle by which light "stays" in a fiber optic.

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It's also the same system of the optics used in lighthouses. No wonder TIR lights are throwers...

SureFire uses cyclo-olefin-copolymer optics behind multi-layed AR coated tempered Pyrex windows. This is not the cheapest way to do it by any stretch. I understand the difference is that the reasonable quantity of light coming straight out of the LED without reflecting off the reflector is not being used as efficiently as when the same light is passing through the optic and being formed into the beam.

I love the collimation of the TIR heads personally. I'm not an optics engineer but with the point source emitters in play the TIR lens makes more sense than using a reflector designed to bounce light from behind a filament. Then again, when I need light on the job it's uppercase LIGHT so I might be biased.

Kroma with a reflector = U2.

And we all know how heavy the U2 is....

So I am all for TIR.

add on, the 97% for reflector is ONLY for the coating itself and not the whole thing.

and even so, the 97% coating is DAMN expensive compared to normal coating for reflectors.