Anything out ther brighter at a distance than our flashlight?

[saabluster]

I'm think you could retrofit our collar on your flash light, saabluster

I should say I think the figures for my sample could have been slightly higher but there are fingerprints all over the reflector.

As far as working as well with domed LEDs we shall see. I have my doubts it will work quite as well with the domed LEDs where the apparent die placement moves depending on the angle of viewing. Maybe a reflector with the profile tweaked to account for this would work though. Secondly I see this being far more difficult to tune with smaller die LEDs. I will only know with more testing though. Thanks for bringing this technology to our attention.

 

[psychbeat]

KOOL STUFF!!

its be neat to see this implemented in the future
for sure!

 

[bshanahan14rulz]

Saabluster, I think perhaps you should focus (forgive me my pun) on using the XP series. XR already tightens the beam some, and would not make full use of the reflecting collar unless it were inside the metal "Cree Ring."

I must say, I'm surprised that it took 3 pages for people to understand what the OP was talking about. At least we got over that language barrier

 

[JB]

OK so I finally received my evaluation sample at the cost of $100. I am happy to report that it works quite well. I measure the surface brightness increase at 58%. It also changes from a cool white to neutral white when the collar is on. Although not quite the "doubling" mentioned by the OP a 58% increase is still a phenomenal achievement. I give this a big thumbs up.:thumbsup:

Excellent news. Any pictures to show?

 

[get-lit]

Although you're getting 58% more surface brightness, that doesn't hold a candle to the ability of a standard reflector or lens to collimate the light to a distant target. Yes you've now gained 58% more source intensity, but you've done so by utilizing the light that could have been directed directly toward the target through collimation. A collimated light with a source intensity of 1x would kill a non-collimated light with a virtual source intensity of 1.58x any day. It's an interesting concept, but I'm absolutely confident that standard reflector and lens collimation methods will prove to outperform it.

Also, regarding the DPR technology; although it is able to capture and collimate that additional light which is emitted forward from the source, the technology has a distinct disadvantage to already adopted methods of collimating that additional light. For instance, the Epson E-Torl lamps do the same, but without having to create a secondary virtual source. Physics can not be cheated - it is impossible to create a virtual mirror of the primary source that is more concentrated than that primary source; in fact it's even impossible to perfectly duplicate it. Virtual sources of that primary source will be less concentrated due to imperfect reflection angles and also due to reflection losses, and the E-Torl lamps already capture that additional light in a simpler method without a secondary virtual source. That method has been used in high power search lights for decades before Epson adopted it for projectors.

edit- on the other hand, if the E-Torl lamps are elliptical, then they also create a virtual source. In that case, the DPR method may have a slight advantage in that it may utilize a bit more of the light than the E-Torl, due to the fact that the convex mirror of the E-Torl blocks some of the light that is emitted from the back side of the light source from being collimated.

 

[Th232]

Although you're getting 58% more surface brightness, that doesn't hold a candle to the ability of a standard reflector or lens to collimate the light to a distant target. Yes you've now gained 58% more source intensity, but you've done so by utilizing the light that could have been directed directly toward the target through collimation. A collimated light with a source intensity of 1x would kill a non-collimated light with a virtual source intensity of 1.58x any day. It's an interesting concept, but I'm absolutely confident that standard reflector and lens collimation methods will prove to outperform it.

I think the point is that you can use additional methods of collimation, e.g. lenses on top of the collar.

 

[get-lit]

I think the point is that you can use additional methods of collimation, e.g. lenses on top of the collar.

In their method, the light that would benefit from collimation to the target is instead already utilized to boost the source intensity. The trade off will not be beneficial over direct collimation toward the target. It's like running on a treadmil with a generator to produce energy to get somewhere, when you could have just run there to begin with. We can kick around that light all we want, but it's not going to be more efficient than directing it straight toward the target from the get go. I wish I saw it differently because it would be a fun new avenue for sure.

 

[saabluster]

Although you're getting 58% more surface brightness, that doesn't hold a candle to the ability of a standard reflector or lens to collimate the light to a distant target. Yes you've now gained 58% more source intensity, but you've done so by utilizing the light that could have been directed directly toward the target through collimation. A collimated light with a source intensity of 1x would kill a non-collimated light with a virtual source intensity of 1.58x any day. It's an interesting concept, but I'm absolutely confident that standard reflector and lens collimation methods will prove to outperform it.

This is not a technology intended for use with a standard reflector. A reflector as is doesn't hold a candle to the ability of a lens to collimate the light to a distant target. With their "light collar" in place this means the aspheric light can throw 58% more than before when it was trouncing the reflector. You seem to have your facts mixed up or just don't understand what's going on here.
Even if you are referring to pure collimization such as is used in the DEFT where I capture some of the light emitted to the sides I can assure you this light collar does more to increase throw. It has to be designed to match the lens it is being used with however.

 

[TorchBoy]

I cannot believe how badly this thread started and how (understandably) slow people were to realise what the two advertisers were badly trying to explain.

 

[DM51]

enginyr... please read Rule 3.

 

[kito109654]

I'm pretty lost with all of this, but is this what they are possibly claiming to be doing? With an aspheric set up you are basically projecting an image of the emitter, so the brighter the emitter is, the brighter it will be projected, giving a higher lux value, more throw, etc. Now, if they are able to take some of the light and reflect it back onto the LED emitter, would they be able to increase the surface brightness of the emitter, and as a result the projected image of the emitter would be brighter?

Oh wow, all this convoluted junk and poor word choice and you just made it all make sense. That "clicked" immediately. Two thumbs up for you!

Fair enough. Throughput is what I mean. I don't want to mislead. We are using an integrating sphere to measure total lumens through the flashlight lens. With this flashlight, using this lens, the reading we get with the retro-reflector in place is almost double the reading we get without it. But just to be clear, the LED is not emitting more photons. We are just getting more through the aperture.

This is much better than what you were saying before. This makes sense. Before, with the poor word choice, you were claiming that the total lumen output somehow increased (from a bare emitter to a collimated one). A before and after of the light output through the lens designed for your reflector makes sense because the lens obviously wouldn't be very efficient without the reflector/recycler.

OK so I finally received my evaluation sample at the cost of $100. I am happy to report that it works quite well. I measure the surface brightness increase at 58%. It also changes from a cool white to neutral white when the collar is on. Although not quite the "doubling" mentioned by the OP a 58% increase is still a phenomenal achievement. I give this a big thumbs up.:thumbsup:

You get to keep it, I hope? That is truly amazing! 58% is great, no one was expecting doubling. My favorite part is how the light temerature (CCT) is lowered by sending some of the ugly blue light back through the phosphor! That is genius and very, very useful! I don't really care much for the handheld flashlight application (I have no practical use for such a light) but both your DEFT and this combined is an amazing jump in technology for the practical use of an LED spotlight. I picture this thing being used from a search and rescue helicoptor or something similar. Unless I'm not understanding it correctly, wouldn't this keep the cost (and size) of a larger version down by removing the necessity for a huge expensive lens? Speaking of a larger helicopter mounted version (obviously not bound by batteries), imagine several (say, 7) of these units be combined and aimed such that the beams overlapped slightly, making a larger, more useful spotlight. Or they could be dynamically controllable (re-aimable, if you will) to all point in the same spot for even more throw potential. Wow.

 

[Chauncey Gardner]

[Inappropriate post deleted - DM51]

What is wrong with you?

Did you confuse the forum you were on?

 

[Th232]

In their method, the light that would benefit from collimation to the target is instead already utilized to boost the source intensity. The trade off will not be beneficial over direct collimation toward the target. It's like running on a treadmil with a generator to produce energy to get somewhere, when you could have just run there to begin with. We can kick around that light all we want, but it's not going to be more efficient than directing it straight toward the target from the get go. I wish I saw it differently because it would be a fun new avenue for sure.

I would disagree with that. First of all, note that with any collimation method, reflector, TIR or lens, the light won't go "straight" at the target as you say, it'll go slightly off to one side, more so for a reflector than with a lens, hence why when someone wants extreme throw with an LED at a certain size, they go for an aspheric and not a reflector. Have a look through the datasheets that various manufacturers put out, then compare with the figures for aspherics that people here have gained from experimental data. Perfect collimation of all light gathered (whether from a reflector or an aspheric) can only come from a point source. Failing that, Aspheric > TIR > reflector, even when the latter two are optimised for throw.

So let's take an LED with an aspheric. The aspheric captures all light emitted up to, say, +/- 30 deg off axis. Assume we have 300 lumens coming out of the LED, 150 hit the aspheric, while the other 150 miss it and are completely wasted. Assume transmission losses to be 10%, that gives us 135 lumens OTF.

With this collar, it captures some of the wasted 150 lumens and redirects it back at the LED &c. as described earlier, giving the 58% increase in surface brightness. Apart from the obvious decrease in total output due to inefficiencies in the collar, the main tradeoff is that the viewing angle has now been greatly reduced, eyeballing the image on their site, I'd call it from 180 deg down to 60 deg.

If we were using a reflector based system, this would throw a lot worse, but see my previous note about throw and reflectors vs aspherics. Our example aspheric, however, doesn't use any of the light past +/- 30 deg, so we have a gain in overall throw due to the greater surface brightness. Note that if the aspheric only captured light between, say, +/- 20 deg, then there will still be a large amount of light lost, hence Saab's comment about matching the lens.

So with the LED, aspheric and everything else being the same, therefore we get 150 * 1.58 = 237 lumens hitting the aspheric, while only 63 lumens is lost. Taking transmission losses into account, that's 213 lumens OTF.

Short version: Viewing angle down, surface brightness up.

Will OTF lumens be lower when compared to a reflector or TIR (especially the TIR)? Gut feeling is that it will be, but I can't say for sure. But will throw increase? I believe yes for a tuned setup, for the reasoning given above.

Enginyr and thezug, my opinion is probably worth as much as a black reflector, but I'd like to second what bshanahan14rulz said, if you come up with something like this for Cree's XP series, I'd buy one without hesitation.

 

[DM51]

Did you confuse the forum you were on?

Thanks for drawing my attention to that post - I've deleted it. I can't think how I missed it before.

 

[get-lit]

Th232, I thoroughly understand the poor etendue relation of a large emitter source coupled with the small reflectors we're talking about here, and that only an impossible infinite etendue can produce perfect collimation etc. That relation applies to standard reflector and lens collimation methods, as well as the reversed reflector of this new method, so we can compare the relative performance of this method to illuminate a distant target by using the all the same emitters with the same size reflectors and lenses.

All that is happening with this method is that the light is being reflected back to the source to make it brighter. It's inherently less efficient than directing it toward the target to make the target brighter instead. With equivalent sized source and optic reflective components when comparing both methods, the effects of etendue relation can be about eliminated for a fairer comparison. That's why the DEFT is not a fair comparison to the prototype they have available. Keep the etendue relations comparable with the same emitters and the same relative sized optics and then we can really compare apple to apples The reflector diameter in their prototype seems about just over 7 times the average emitter size, so we should be comparing with a DEFT type lens that size on that emitter, and you'll get a lot more than 58% more illuminance upon the target. Throw a collimating lens on the prototype and it should come closer, but it still couldn't quite match a DEFT type lens of equivalent size of the prototype reflector.

When comparing the two methods of target illumination under equivalent etendue, one in which light is typically reflected toward that target, and another in which the light is being reflected back toward the source, the method which reflects light back toward the source is adding two additional loss components; the reflectance of the emitter and an additional minor angular accuracy loss.

I'm still keeping an open mind and my hopes up however. A fair comparison is needed for me to really know if there's some magic to it that I'm not seeing.

 

[saabluster]

Th232, I thoroughly understand the poor etendue relation of a large emitter source coupled with the small reflectors we're talking about here, and that only an impossible infinite etendue can produce perfect collimation etc. That relation applies to standard reflector and lens collimation methods, as well as the reversed reflector of this new method, so we can compare the relative performance of this method to illuminate a distant target by using the all the same emitters with the same size reflectors and lenses.

All that is happening with this method is that the light is being reflected back to the source to make it brighter. It's inherently less efficient than directing it toward the target to make the target brighter instead. With equivalent sized source and optic reflective components when comparing both methods, the effects of etendue relation can be about eliminated for a fairer comparison. That's why the DEFT is not a fair comparison to the prototype they have available. Keep the etendue relations comparable with the same emitters and the same relative sized optics and then we can really compare apple to apples The reflector diameter in their prototype seems about just over 7 times the average emitter size, so we should be comparing with a DEFT type lens that size on that emitter, and you'll get a lot more than 58% more illuminance upon the target. Throw a collimating lens on the prototype and it should come closer, but it still couldn't quite match a DEFT type lens of equivalent size of the prototype reflector.

When comparing the two methods of target illumination under equivalent etendue, one in which light is typically reflected toward that target, and another in which the light is being reflected back toward the source, the method which reflects light back toward the source is adding two additional loss components; the reflectance of the emitter and an additional minor angular accuracy loss.

I'm still keeping an open mind and my hopes up however. A fair comparison is needed for me to really know if there's some magic to it that I'm not seeing.

Your obviously not getting it. This light collar is not intended to replace any means of collimation. All it is is a hemispherical reflector with the top lopped off to allow some light to escape. You still have to collimate the light that comes out.

It is true that this light collar reduces the optical efficiency of the system vs a system like the DEFT's but the benefits of the light collar out-way the negatives when the goal is throw.

I would propose my own design here. Since their design is all but impossible to use with a reflector I thought of a new design for use with a reflector. It would be a hemispherical reflector that hovers over-.top the led but allows the light to escape from the sides where it can hit the reflector. This will give a beam with out the spill but that does have a hotspot and corona. It will not be as intense as a lens but the beam will be broader.

 

[get-lit]

..You still have to collimate the light that comes out..

Oh I get it all right; what I'm saying is that if you were to instead utilize a lens that is the size of that reflector/collar they are using, it is inherently more efficient at directing the light to the target than a smaller lens on top of that reflector/collar. The utilization of that outer light by directing it at the target is a more efficient method than directing that side light back to the source because when directing that side light back to the source rather than to the target there are at least two additional losses. Pretty simple.

 

[saabluster]

Oh I get it all right; what I'm saying is that if you were to instead utilize a lens that is the size of that reflector/collar they are using, it is inherently more efficient at directing the light to the target than a smaller lens on top of that reflector/collar. The utilization of that outer light by directing it at the target is a more efficient method than directing that light back to the source because when directing that side light back to the source rather than the target there are at least two additional losses. Pretty simple.

Ok I'm going to repeat myself word for word.

It is true that this light collar reduces the optical efficiency of the system vs a system like the DEFT's but the benefits of the light collar out-way the negatives when the goal is throw.

Lenses alone cannot, let me repeat, cannot match the light collar's ability to increase surface brightness and therefore throw.If you want better throw from an aspheric design the collar is far superior. You do understand I am the designer and maker of the DEFT right? I am telling you that their system is superior to mine.
Let's say we had two lights with the same outer dimensions and with the same diameter main lens. One has a pre-collimator just over the LED to redirect the otherwise wasted light and the other has the collar.

The one with the collar will have a more intense beam and higher lux readings but a smaller beam size. You are right that there is more loss with the collar and this is reflected(no pun intended) in the fact that the size of the beam is smaller.

The one with the lens to redirect will indeed have more throughput and a larger beam size but less intensity.

It should also be noted again the huge benefit the collar offers of warming the output of the LED. Everyone loves neutral white LEDs and with this system in place you get an aspheric light with the efficiency of a cool white but the color of a neutral white. That's right neutral white without the efficiency hit!

 

[kito109654]

Get-lit, I'm sure you're already aware of these three points but I'm gonna restate the obvious just in case.

1. Maximum throw is the goal.
2. Higher surface brightness equals greater throw.
3. At the expense of overall efficiency, the collor increases surface brightness.

That's all.

 

[Th232]

It should also be noted again the huge benefit the collar offers of warming the output of the LED. Everyone loves neutral white LEDs and with this system in place you get an aspheric light with the efficiency of a cool white but the color of a neutral white. That's right neutral white without the efficiency hit!

Just curious, what do you think the drop in output is if you compare a bare LED to one with the collar? Personally I'd have to say that the collar gives us that efficiency hit, but I obviously haven't played with it yet so I don't know how large that drop is.