LS optics

[r2]

Nichia white LEDs are great for small lights like the Arc AAA and the Photons, and one of the things that makes them so useful is the beam pattern. A reflector can capture a little bit of spilled light, but it doesn't make a big difference.

Why is the LS different? LS based lights require external optics to get a useable beam. Is there a technical reason that they are different, or is it just a design decision by Lumileds? The bare emitter is pretty small. I would love to have an Infinity with a LS instead of a Nichia 5mm with the brightness of an Arc LS 1AA. Even if the 1AA tube on the Arc LS was thinner (instead of being the same diameter as the 123 tube) the head would still have to be fat to accomodate the optics.

What is the beam like on a bare LS emitter? I don't recall seeing that discussed much. Is it completely unusable? Does it have to be that way, or are we just hostage to Lumiled's packaging decisions? I haven't heard much recently about Nichia's upcoming LS competitor; is there any chance it will have the optics it needs in the emitter packaging?

- Russ

 

[McGizmo]

R2,
The emitter beam itself is a very nice but wide angle beam. If you look at how much clear epoxy is above the die in a 5mm LED and then look at how short the distance is from the die to the top of the lens on the Luxeon emitter, I think you will understand the difference. The 5 mm LED's can have their heads shaved off and will also give a wider beam angle.

All Nichia LED's use the same die. The difference in their beam angles is a function of the length of the LED body.

If the Luxeon emittter had a taller head (lens further from die) it would have a narrower beam angle. I suspect that the Luxeon series was designed primarily for more general lighting where a narrow beam or spot is not desired. There may also be structural issues as the LE is not a solid cast part as the 5 mm LED's are.

 

[rlhess]

If you look at the Luxeon Web Site somewhere there you'll find the tech data. The two Lambda lights I have (Ill and Ill Pill) have the batwing dispersion which has less light straight on, so the optics are needed. The batwing pattern looks like it might work well with conventional reflectors (like a Mag) but I haven't seen that.

The TechAss PR2s are batwingish and work well with the generic 2C flashlight reflectors providing a VERY tight spot.

Cheers,

Richard

 

[**DONOTDELETE**]

Why not a bare LS emitter at the base of a MagLite reflector, positioned right about where the incandescent filament would normally be? Wouldn't the focusing ability really come into play then?

 

[txwest]

Mr. B.,
Didn't I buy the lambda LS 2D/3C Mag conversion with no optics from you??
This is exactly the light you're talking about. TX

 

[Lux Luthor]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by MR Bulk™:
Why not a bare LS emitter at the base of a MagLite reflector, positioned right about where the incandescent filament would normally be? Wouldn't the focusing ability really come into play then?<HR></BLOCKQUOTE>

I've made a number of attempts to use emitter/reflector combinations. They work alright, but you don't get as good of a spot at the center. The reflectors are mostly designed for bulbs that radiate in all directions. The emitters only radiate forwards.