Optic Recommendation

I'm looking into having a custom light made, and I am looking to include a TIR optic. I would like the light to be about an inch in diameter, max, so the internal bore should probably be about 21mm or less. It will be based on an 18mm diameter battery (e.g. 18650), so the TIR need not be smaller than 18mm.

At this point, the dilemma is figuring out which TIR/emitter combo will give me the best color and throw I can achieve in this size light. Because I'm looking to maximize lux, I am currently leaning toward an MC-E with an appropriate TIR optic, but I'm open to other LEDs. As for color, I want a clean, bright white color - no yellow and no blue (5000k?).

If anyone can make specific recommendations for the emitter (bin and all) and/or the TIR (brand, size, etc.) I would really, really appreciate it. I've searched around and I'm having difficulty finding anything specific.

Thank you!

optics wont have much to do with color, or tint. that will depend more on your LED. around 5000k sound good for a crisp white tint. the optic will determine the beam pattern.

if you want to maximize lux, a MC-E might not be a best option. ive played around with a number of 20mm optics, most being "narrow beam" optics, and these optics especially can be very picky when it comes to what LED its used with. some work, and some produce an atrocious beam, and some are a nice surprise. so its not as simple as picking an optic that fits in the head, and your choice of LED. some experimenting will be necessary before hand.

general rule, is that a smaller LED will provide more throw/lux than a larger LED in the same size head. i think the best LED options would be XP-E2 and XP-G2, and if you are planning to push the LED really hard to around 3 amp, a XM-L2 would be a better option than MC-E.

i have a couple of 20mm optics designed to be used with XM-L that i purchased from a chinese dealer, which i cant remember whom right now, but theyre a much smaller dealer when compared to DX. im using a XP-E2 with one, and it produces a beam very similar to surefires with TIR+XR-E LED, such as the LX2, L1, E2L, E2DL and such. that XP-E2 and optic combination is the most lux ive gotten out of a 20mm optic while still having an acceptable beam. the other i have a XM-L2 and it has significant less lux. but this optic is very LED friendly, and works well with many different LEDs. i have a bunch of different carlco 20mm narrow optics as well, and didnt care for the beams it produces, even after trying out a number of different types of Cree and nichias LEDs

I was only mentioning color/tint because I'm looking for an emitter recommendation to go with an optic.

My inclination is to go with an XM-L, but I've read that people often achieve greater throw with MC-E emitters. XP-E and XR-E don't appear to have enough raw lumens to work for me.

The Surefire E2D LED Defender is the model for this pursuit. I basically want a custom version of that light - with more lumens to start. Is my best option really going to be getting an E2D and re-housing it? I just assumed there'd be something better available. I wasn't aware of the need to experiment with TIR optics, though.

The actual rule is that LEDs with higher apparent surface brightness throw farther. It happens that smaller LEDs generally have higher apparent surface brightness, thus the general rule that smaller LEDs throw farther.

The outer boundary of the MC-E dice is about the same as the size of the XM-L die, and the XM-L (especially XM-L2) puts out more light, so the die is brighter.

That's not the end of the story though. The dome appears to magnify the die size, so the apparent die size is bigger than the actual die size. This is why de-doming increases throw - it reduces the apparent die size, increasing the apparent surface brightness.

The dome on the MC-E is bigger than the one on the XM-L. I don't know what that does to the magnification, perhaps someone will chime in on that. Even if the bigger dome results in less magnification, I doubt will be substantial enough to overcome the higher output of the XM-L2.

The E2D must be using an XP-G slightly overdriven, or perhaps an XP-G2 to get 500 lm. To get the same throw, you'd have to drive an XM-L to about 1200 lm. That's based on virtual die size taken from this page: http://lux.yi.org/led/. At that point you'd have the same lux in a bigger hotspot with brighter spill. Oh, and that assumes you have comparable optics, which means about 40% larger diameter for the XM-L. The only way you're going to get MORE throw is to improve the optics, de-dome the LED, or overdrive something pretty hard.

DIWdiver,

Thank you for the thorough reply. I'm looking into an XM-L2 paired with the optic found here, which I believe is a TIR. Could someone confirm?

Will this combination require any experimentation to get right, or will it be fairly plug and play? I can't really fiddle with it, as the LED/driver/housing will be crafted by the custom maker.

Finally, what kind of OTF lumens could be expected with 93% efficiency on an XM-L2 at 3A? I assume this would be a more impressive light than the E2D?

Thanks for the input everyone!

that optic looks like a great choice. its designed for the XM-L2 is chances are the beam wont be atrocious.
XM-L2 pushed to 3 amps should yield close to 1000 OTF lumens.

are you planning on doing anything with the old E2DL driver?