CREE says XR-C can throw light farther than XR-E, discuss?

[VanIsleDSM]

In their portable lighting PDF, http://www.cree.com/products/pdf/XLampApp_Portable.pdf

"with narrow angle TIR optics, XLamp XR-C LEDs can put out around 50% more peak light intensity with XLamp XR-E for maximum LED light throw"

Is this common knowledge? I'm not a big flashlight buff, mostly into fixed and automotive LED lighting.. but I do have a lathe now so I think I must build my own torch soon.

So first off, what is a TIR optic? the only acronym I can think of that has to do with optics is total internal refraction, but that doesn't really make sense to me because that would mean no light would escape the optic?

Now why is it that the XR-C can produce more light intensity? I wonder if they mean 350mA to 350mA? or if the XR-C @ 500mA max could still be 50% more intense than an XR-E @ 1000mA max? What is this increase in intensity attributed to? something to do with a differently sized die from which you can collect the light into a smaller angle? ..both emitters have a 90 degree radiation pattern.

Interesting anyway..

 

[TigerhawkT3]

Yeah, that's what TIR stands for. I must admit that I never considered what it should mean... that gave me a laugh and a half.

Looking at that PDF (3MB for two pages - beware), the XR-E is more efficient and rated at higher current levels. At 350mA, the XR-C is 60L, while the XR-E is 80L, and the XR-C's max is 0.5A while the XR-E's is 1A. The datasheets for each one list very similar radiation patterns, so I don't know how the XR-C can provide higher "intensity." Perhaps the answer is as you guessed, a smaller die. I'm not sure, though.

 

[IMSabbel]

Wellll...
Depends on the size of the XR-C led die.

One way to make lights more efficient can be lower current densities, resulting in lower surface brightness.

So relatively, a (hypothetical) 0.5*0.5mm XR-C with 100 lumens could throw 41% further than a 1*1mm XR-E with 200 lumens.

 

[clg0159]

Total internal "reflection"

 

[Lightingguy321]

Cree makes a Total Internal Reflection optic type device for focusing the beam of an LED, if you remember Luxeons you probably remember the NX-05 which was Lumiled's version of a Total Internal Reflection optic. Basically it channels all of the light into a fairly even spread beam. The only down side is some optics lack side spill and tend to mirror image the LED die in the beam (that mean carrying artifacts along), other wise a good optic shouldn't have this problem. There are ups and downs to using TIRs just like when you are using reflectors to focus LEDs.