Why do Luxeon lights use textured reflectors?

Why do we need a textured reflector when using a Luxeon based light? It is a well known fact that a smooth reflector projects "all" the light from the source, and that a textured one does not. I use as an analogy a light reflected off a clean mirror, and one that is reflected off a smudgy one. Some light is absorbed by the smudgy mirror. With incandescent light sources, a textured reflector is needed since it helps smooth out the projection of the filament and the other imperfections in the lamp's output. From what I know, a Luxeon based light has no such imperfections, otherwise known as artifacts. If I am missing some hidden reason why all lights I have seen use a textured reflector, I would like to know.

As a means of comparing a light's output to it's reflector's surface, I mention my two lights using IMS's SO17XA smooth reflector. One is a Longbow Micra with a Luxeon I. The other is a modified L1 bezel with a Luxeon III. Both lights project a beautiful, pure, and "artifact-free" pattern with the small 17mm reflector. If the Micra and L1 can look so nice, why can't other lights look the same with smooth reflectors?

In the case of Don's PR-T and Aleph3 bezels, wouldn't there be much greater output and throw if a smooth reflector of the same size was used?

Luxlover

I think that texturizing is used as a way to reduce beam imperfections and is somehow related to making it easier to use the beam for reading. Essentially, each spot of light coming from the front of the flashlight is an integrated average of several reflections.

As LED output has become more uniform in color and intensity, this has become less of an issue. I have retail flashlights with polished reflectors - nice throw, but I can hardly use them at short range.

More spill. /ubbthreads/images/graemlins/smile.gif

I have same thoughts. Reflectors need to be very reflective, smooth to get lumens out of leds, which in small led lights are minimal at best. I get more light output with my Fraen in VIP, than the BH head, using the orange peel reflector. Fraen, of course, is not a reflector, but shows how light is lost in BH. Not lux, but overall light output. I tried this at the recent Bay Area Get Together. Gadget Lover tested my light with fresh rechargeables, using first, the BH, then the Fraen. It was the VIP, with 2AA body, at the "high" output position. and 2000mAh GP's. The BH (Bulk Head) registered 35 (lumens), on Gadget Lover's litter container lumen tester, and the Fraen registered 43 (lumens). Gadget Lover's testing device uses a plastic cat litter container, you buy the litter in, with added attached parts, including a light meter. The devise is very accurate. My SureFire 6R measured 51 (lumens). It is advertised by SureFire at 50 lumens. Other lights were measured that night, all within advertised lumens. The point here is that the output of the Fraen was more than the textured BH. Now I need a smooth BH reflector to test at home. My crude setup at home using a LM631 to measure light output, also shows disparity between BH and Fraen.

Bill
Bill

Why do Luxeon lights use textured reflectors? Because for some of us, a blotchy beam is much worse than a light that can't throw too far. In some cases you will need throw and in those cases, you bring out the light without the untextured reflector.

Not all Luxeon lights use textured reflectors. Heliotek`s HTE-1 has a deep, mirror-smooth reflector that produces the narrowest beam I have ever seen in an LED light. It is not ringy or blotchy either. I suspect if the reflector surface were textured the hotspot would be wider, even if the overall lumen output might be the same.


/ubbthreads/images/graemlins/grin.gif

[ QUOTE ]
From what I know, a Luxeon based light has no such imperfections, otherwise known as artifacts. If I am missing some hidden reason why all lights I have seen use a textured reflector, I would like to know.

[/ QUOTE ]

In theory, you might be right. In practice, this doesn't hold true (except for one exception--the Arc 4+). Almost every single Luxeon flashlight I have that uses a smooth reflector has some artifacts. The XM3s have minor artifacts in the outer part of the hotspot, the Streamlight 3AA Lux's has moderate artifacts--mostly rings-- and the corona does not smoothly blend with the hotspot.

Side emitters such as the Terralux Ministar are LOADED with artifacts.


Back to the exception. The Arc 4 has a relatively smooth reflector (in a certain light, it looks like there could be an extra fine texture applied to it, but for now I'll assume it is smooth), and it has no artifacts. So, you are right in that it is possible, but you need a high quality reflector that is focused properly and also matches the luxeon in the light.


My luxeon lights with textured reflector all have perfect beams with zero artifacts--this includes the Surefire L4, L2s, and Pelican M6 LEDs.

[ QUOTE ]
eebowler said:
Because for some of us, a blotchy beam is much worse than a light that can't throw too far.

[/ QUOTE ]

Agreed! Count me in that crowd. I'll take top notch beam quality over throw ANY DAY.

[ QUOTE ]
luxlover said:
I use as an analogy a light reflected off a clean mirror, and one that is reflected off a smudgy one. Some light is absorbed by the smudgy mirror.

[/ QUOTE ]

there's a difference between a textured reflector, and a frosted one, which would be analogous to a smudgy mirror. frosted reflectors would absorb some light, but textured reflectors would merely scatter the light emitted more than a smooth reflector would.

Surely if you did not have reflector texture you would see a really dark, and obvious void in the centre of the beam unless the LED was specifically defocused?

Al,
Much more so with the LuxV but there is a chance to see it with a LuxIII to some extent.

The Luxeons do have some artifacts as has been stated and there is also unevenness in color manifest in many. The orange peal reflector has areas of reflective surface with angles off from the parabolic and reflected light will not be added to the collumation in the beam. This light will for the most part still exit the light.

It all does boil down to personal preferences and needs. I am more than willing to sacrifice the ultimate distance at which I can illuminate in echange for a more uniform dispersion of light at ranges I can illuminate. As mentioned above, this becomes even more significant as the target gets closer and you are more concerned with illumination of elements within the target such as words, components, or what have you.

How does IMS get such a nice beam out of their SO17XA smooth reflectors? I always thought you had to texture it.

[ QUOTE ]
McGizmo said:

It all does boil down to personal preferences and needs. I am more than willing to sacrifice the ultimate distance at which I can illuminate in echange for a more uniform dispersion of light at ranges I can illuminate. As mentioned above, this becomes even more significant as the target gets closer and you are more concerned with illumination of elements within the target such as words, components, or what have you.

[/ QUOTE ]

Amen, Pastor McGizmo, Amen!!

Let's get the beam quality PERFECT first, no matter what it takes. We can push the distance factor later with more power and a deeper, more focused reflector as Surefire demonstrates with the L6. As soon as they boost the power output, we can shallow the reflector back out again to regain the spill ala the L4 or L5.

Can I get an Amen!?