# Has anyone read any new LED in research?



## CalgaryGuy (Jan 15, 2009)

Has anyone read any new LED in research? Cree and Rebel has been out for over 2 years now and their efficiency seem to have been push to the limit. Latest cr123 light from Fenix doesn't have much improvement as they used to be. Luxeon LED was the king for about 3 years and taken over by the other two. If anyone read any new Led, please point me to the right direction. Thanks.


----------



## xpea (Jan 15, 2009)

interested too to get some fresh news here. It's so boring to see these "new" Q5 and R2 lights...

So when is the next jump in efficiency ? 




PS: I don't consider MC-E and P7 new stuff, same efficiency as 2 years old parts...


----------



## Glenn7 (Jan 15, 2009)

This is a quote from sunlites website:

Technology

We make the LED head starting from LED chip level. It has better thermo management than Cree, Lumileds 
and Seoul LEDs. The thermal conductivity of our LED is 8 times higher than Cree’s Q5 LED

The output light beam of Eagle 8W is more parallel and can reach further than any of the LED flashlights 
using same size reflector but with Cree Q5, K2 TFFC or Seoul P4 LEDs. Our LED chip is 1.5 X 1.5 mm, larger 
than the LED chip (1 X 1 mm) used for Cree Q5, K2 TFFC or Seoul P4 LEDs, so it can be driven at much 
higher current.

Our LED chip is not packaged in the 5mm dome as other power LEDs. The reflector of our flashlight sees the 
1.5 X 1.5 mm LED chip, instead of a light source enlarged by the 5 X 5 mm dome. Our flashlight therefore 
can throw the light further than other flashlights.

and here is a thread for in CPF of some of us that have bought one https://www.candlepowerforums.com/threads/217294 :thumbsup:


----------



## Tirodani (Jan 15, 2009)

There's been discussion very recently about exciting experimental results from Cree. Should be easy to search out.


----------



## Kestrel (Jan 15, 2009)

I've been wondering about this exact topic as well and have been tempted to start a thread like this myself over the last few days. Even though I'd like to see some brighter emitters on the market (wouldn't everyone), all I _*really want*_ is for someone with the inside scoop to say that company xxx expects LED's with yy% higher output to be released for the the consumer market approximately z months from now.


> experimental results


I'm involved with research where I work and I know that anybody can write about good results in the laboratory. I've seen promotional brochures from our organization that say our work is getting all these fantastic results, and I'm thinking, Do they even work here? Our lab results were nowhere _near_ that promising.:thinking::hairpull:


----------



## Glenn7 (Jan 15, 2009)

Kestrel said:


> I've been wondering about this exact topic as well and have been tempted to start a thread like this myself over the last few days. Even though I'd like to see some brighter emitters on the market (wouldn't everyone), all I _*really want*_ is for someone with the inside scoop to say that company xxx expects LED's with yy% higher output to be released for the the consumer market approximately z months from now.
> 
> I'm involved with research where I work and I know that anybody can write about good results in the laboratory. I've seen promotional brochures from our organization that say our work is getting all these fantastic results, and I'm thinking, Do they even work here? Our lab results were nowhere _near_ that promising.:thinking::hairpull:



did you go to the forum i posted? - you will see an LED that is new and out shines the others - i only ask because the question was asked - then i showed you were a brighter led was - then you said where is a brighter LED? :thinking:

and BTW sunlite is bringing out a 16W LED in a single die that will put out more than 500 lumens - that will kill the P7/MC-E - not to mention their 8w one they have now that produces 300+ lumens


----------



## Kestrel (Jan 16, 2009)

Sorry to miss it, I could've sworn that your post wasn't there when I posted, but most of my brain cells are working on a big thread I'm running at the moment. Will check back tomorrow or over the weekend. Thanks,
K


----------



## sol-leks (Jan 16, 2009)

I know this may sound like heresy to say, but I wonder if research has slowed down a little simply because LED's are already so bright. I mean of course we are talking about efficiency even more than brightness, but led's are already quite efficient. It seems to me that the biggest area for led research is perfect tint and creating a feasible led for home lighting use.
I guess I just remember not too many years ago when we were all carrying around enormous maglites that put out a pretty feeble beam, and being happy with it while now I have a lod with a 10440 that can put it those old mags to shame.


----------



## Glenn7 (Jan 16, 2009)

Thats ok buddy - just trying to help


----------



## mejesster (Jan 16, 2009)

http://www.engadget.com/2009/01/14/researchers-develop-higher-efficiency-leds/
Is that of interest?


----------



## CalgaryGuy (Jan 16, 2009)

Thanks guys for your input. I agree with Kestrel that unless they can actually produce the lumen that they claim, there is no point on claiming "experimental result" and unable to archive what they claim. I sure hope that Surefire UB2 Invictus is still in progress, 400 lumen on 2 x 123.


----------



## DM51 (Jan 16, 2009)

This thread belongs in LED rather than LED Flashlights, so I'm mving it now.


----------



## was.lost.but.now.found (Jan 16, 2009)

Glenn7 said:


> and BTW sunlite is bringing out a 16W LED in a single die that will put out more than 500 lumens - that will kill the P7/MC-E - not to mention their 8w one they have now that produces 300+ lumens


 
I could be mistaken but while this may be a gain for light output from a single die, is it not a horrible loss in efficiency compared to other leds on the market today (31lm/watt compared to nearly (or over) 100lm/watt for many cree and seoul leds)?



Glenn7 said:


> We make the LED head starting from LED chip level. It has better thermo management than Cree, Lumileds
> and Seoul LEDs. The thermal conductivity of our LED is 8 times higher than Cree’s Q5 LED


 
Isn't the main issue with heat syncing not necessarily getting the heat off the physical led, but rather getting it through a network of epoxy and metal to the surrounding flashlight body? Again I could be wrong; this is just by observations from CPF posts and readings over the last few months.


----------



## Stefans (Jan 16, 2009)

161Lumens/Watt seems to be Cree:s latest proved result:
http://flashlightnews.org/story1825.shtml

If that could have 130-140 Lumens/Watt driven att 3W then that would be sweet.


----------



## 2xTrinity (Jan 16, 2009)

> The output light beam of Eagle 8W is more parallel and can reach further than any of the LED flashlights
> using same size reflector but with Cree Q5, K2 TFFC or Seoul P4 LEDs. Our LED chip is 1.5 X 1.5 mm, larger
> than the LED chip (1 X 1 mm) used for Cree Q5, K2 TFFC or Seoul P4 LEDs, so it can be driven at much
> higher current.


I understand how larger die area can accomodate more current, and have lower thermal resistance than a small die.. but how does could that possibly be MORE collimated in the same sized reflector than a light with a smaller, more point-like die? 



> I could be mistaken but while this may be a gain for light output from a single die, is it not a horrible loss in efficiency compared to other leds on the market today (31lm/watt compared to nearly (or over) 100lm/watt for many cree and seoul leds)?


So much so that you could overdrive a Cree R2 to mayble 1.3 Amps, and get 300 lumens. Compare that to 300 lumens at 8 watts. Even despite the better thermal conducitivity, 8 watts is so much that it would more than offset the improved thermal conductivity and STILL be running hotter than the "overdriven" Cree R2 pulling just about 4...


----------



## glenda17 (Jan 16, 2009)

I don't think any of these LED's are being developed for flashlights. If flashlights are .1% of their business I would be surprised. There is no way the flashlight market could be supporting the R&D costs.


----------



## jashhash (Jan 17, 2009)

Sunlite claims that removing the dome of an LED increases throw. Is there any way to remove the dome of a Cree?


----------



## Ryanrpm (Jan 17, 2009)

jashhash said:


> Sunlite claims that removing the dome of an LED increases throw. Is there any way to remove the dome of a Cree?



I don't know that they claim removing that dome will increase throw. They claim rather that by not having a dome just gives you a smaller light source which makes a tighter beam. Sunlite LED's are not designed to be used with a dome.

You could remove the dome of a Cree, but you would then have to adjust the height of the emitter to get the correct focus. That dome helps position the light source inside the reflector. 

Also, correct me if I'm wrong, but if you remove the dome from a Cree, the emitter now sits inside a small 'bowl' and might not have all of its light reach the reflector.


----------



## saabluster (Jan 17, 2009)

jashhash said:


> Sunlite claims that removing the dome of an LED increases throw. Is there any way to remove the dome of a Cree?


Yes. It happens all the time with Crees without even trying. The glass dome is very easy to knock off. The result is an LED with a reduced apparent die size which does help with throw but along with it comes a tint shift and reduction in lumen output somewhere in the 25-30% range.


----------



## saabluster (Jan 17, 2009)

Ryanrpm said:


> I don't know that they claim removing that dome will increase throw. They claim rather that by not having a dome just gives you a smaller light source which makes a tighter beam. Sunlite LED's are not designed to be used with a dome.
> 
> You could remove the dome of a Cree, but you would then have to adjust the height of the emitter to get the correct focus. That dome helps position the light source inside the reflector.
> 
> Also, correct me if I'm wrong, but if you remove the dome from a Cree, the emitter now sits inside a small 'bowl' and might not have all of its light reach the reflector.


Yes Ryan it does increase throw and that is essentially what they are saying. The "tighter" beam is refering to the more collimated beam because of it being closer to a point source light. That means the light rays are more parallel to one another and will go farther before they spread apart to the point where the intensity of the beam is decreased and you cannot see a target. 
Also the dome is never used to "center" the LED in a reflector as it has a very weak bond to the underlying metal ring. The metal ring is what is used to center with. If you remove just the dome then yes the die would rest in what might be described as a bowl but you can also remove that "bowl" or ring that surrounds the die. The die actually sits right on top of the ceramic so that if the ring was removed the light from the die would be able to go a full 180 degrees.


----------



## Ryanrpm (Jan 17, 2009)

Why would there be a decrease in about 30% of the lumens if the dome were removed? Whether the dome is there or not it still emits the same amount of light, right?


----------



## jashhash (Jan 17, 2009)

I think the light output becomes less as a result because the silver ring consumes a lot of the light. But if the silver ring were removed then we run into problems of thermal management.

I read an article regarding fully immersed PC's last week. Apparently some guys found that they could put all the components of their computer (except the hard drive) and immerse it in silicon oil and it would still work because the oil is non conductive and at the same time the oil would provide cooling for the components. I'm wondering if the same thing could be done in a flashlight. If you could somehow glue a cree (with the dome removed of course) to the base of a reflector and then fill the space between the reflector and lense with clear silicone oil. That should provide an improvement in heat dissipation and at the same time give a tighter beam. The downside to this is that everything will have to be thoroughly sealed and frozen in place. The flashlight bezel would have to be sealed with epoxy & the hole in the reflector would need the same treatment.


----------



## Glenn7 (Jan 17, 2009)

well i just held the aspheric lens from the DEFT in front of the 8W and WOW! i recon you could burn ants @ 5 meters :naughty: 
it might be something that you want to look at saabluster


----------



## saabluster (Jan 17, 2009)

Ryanrpm said:


> Why would there be a decrease in about 30% of the lumens if the dome were removed? Whether the dome is there or not it still emits the same amount of light, right?


There is more than one reason. When you remove the dome of a Cree you expose the gel underneath. The gel is not left with a perfect surface and more often than not has tears that run through it which cause the light to diffuse and reflect in many different directions. One other thing to consider and what is not readily apparent is the lengths the manufacturers go to in index matching. The die has a coating on it thats aids in light extraction. This has its own index of refraction. Then it has phosphor over that. Next you have the optical gel that goes in between the phosphor and the glass dome(on the XR-E). After that you have the glass . And finally they have to take into consideration the index of refraction of air. They do their best to make the transition "gentle" when going from one material to the next by carefully choosing the material (among others)by its index of refraction. If the difference from one material to the next is too great it can cause excessive internal reflection and not allow the light to escape. By removing the dome you are undoing all the hard work of the researchers to maximize the output of the LED package. 




jashhash said:


> I think the light output becomes less as a result because the silver ring consumes a lot of the light. But if the silver ring were removed then we run into problems of thermal management.


The ring while not 100% efficient is a reflector and is designed to boost the output of the LED package so it would be wrong to say that it consumes a lot of light. More like it redirects a lot of light. Also the ring plays absolutely *no* roll in thermal management. 



jashhash said:


> I'm wondering if the same thing could be done in a flashlight. If you could somehow glue a cree (with the dome removed of course) to the base of a reflector and then fill the space between the reflector and lense with clear silicone oil. That should provide an improvement in heat dissipation and at the same time give a tighter beam. The downside to this is that everything will have to be thoroughly sealed and frozen in place. The flashlight bezel would have to be sealed with epoxy & the hole in the reflector would need the same treatment.


There is probably a way to make something _like_ this work but the materials would have to be chosen very carefully and I doubt that particular oil would work very well. For many reasons.


----------



## saabluster (Jan 17, 2009)

Glenn7 said:


> well i just held the aspheric lens from the DEFT in front of the 8W and WOW! i recon you could burn ants @ 5 meters :naughty:
> it might be something that you want to look at saabluster


Since I know of no other way to get those LEDs than to buy the entire light(since they apparently make the LED themselves) that would make for some some very expensive LEDs. I would like to know more about them though. I am very doubtful that they have managed to beat Cree in surface brightness yet. Take the head off the DEFT and just use your hand to focus the DEFT's lens. It is setup to project the beam at close to infinite but try focusing it where the die is visable a few meters in front of you. I am guessing this is what you did with the 8W and is why it seems so intense.


----------



## comozo (Jan 17, 2009)

jashhash said:


> I think the light output becomes less as a result because the silver ring consumes a lot of the light. But if the silver ring were removed then we run into problems of thermal management.
> 
> I read an article regarding fully immersed PC's last week. Apparently some guys found that they could put all the components of their computer (except the hard drive) and immerse it in silicon oil and it would still work because the oil is non conductive and at the same time the oil would provide cooling for the components. I'm wondering if the same thing could be done in a flashlight. If you could somehow glue a cree (with the dome removed of course) to the base of a reflector and then fill the space between the reflector and lense with clear silicone oil. That should provide an improvement in heat dissipation and at the same time give a tighter beam. The downside to this is that everything will have to be thoroughly sealed and frozen in place. The flashlight bezel would have to be sealed with epoxy & the hole in the reflector would need the same treatment.


 Here's what you could use Fluorinert. 
http://products3.3m.com/catalog/us/...oilgas_3_0/command_AbcPageHandler/output_html

Some years ago when Techtv was around the ScreenSaver shows Joshua "Yoshi" DeHerrera constructed a pc with components submerged in this fluid http://en.wikipedia.org/wiki/Yoshi_DeHerrera
Screen Savers Techtv history A great show that I miss http://en.wikipedia.org/wiki/The_Screen_Savers


----------



## jashhash (Jan 18, 2009)

yes I've been looking into Fluorinert but the problem with that stuff is it cost around $700.00 per gallon. Also I'm not sure of the optical clarity of Fluorinert. I was considering using Deionized water which is not electrically conductive, & because Aluminum wont cause the water to re-ionize it might work. 

So I've decided against removing the dome since that will cause more problems than it solves. Actually it may be totally unnecessary to remove the led dome in order to remove that magnification effect. It appears that simply immersing the whole LED in water will reverse the magnification effect caused by the dome. I took a couple of comparison shots to verify my hypothesis. I took out a glass and balanced my camera around the rim of the glass to take these shots. One shot was taken dry, the other was taken with just enough water to cover up the dome. It appears that simply immersing the LED causes the die to shrink significantly reducing it's surface area to less than half of the non submersed. 






This picture was taken before





this picture was taken after immersion





This picture compares both side by side


----------



## saabluster (Jan 18, 2009)

jashhash said:


> So I've decided against removing the dome since that will cause more problems than it solves. Actually it may be totally unnecessary to remove the led dome in order to remove that magnification effect. It appears that simply immersing the whole LED in water will reverse the magnification effect caused by the dome. I took a couple of comparison shots to verify my hypothesis. I took out a glass and balanced my camera around the rim of the glass to take these shots. One shot was taken dry, the other was taken with just enough water to cover up the dome. It appears that simply immersing the LED causes the die to shrink significantly reducing it's surface area to less than half of the non submersed.


Excellent work! I would like to point out however that it may just be easier to encase it in a clear epoxy so it can still be used in a light. It would achieve the same thing, that is apparent die size reduction. That is unless your goal was to provide the additional cooling by running a liquid over it. In that case you would want to remove the dome and ring so that the liquid could run directly over the surface of the die. Otherwise the cooling provided by the liquid would hardly make any difference in the output of the LED because the glass and gel around the die would not transmit the heat fast enough to matter. Also if you are trying to run the LED real hard the water may boil when in contact with the hot die. It would depend on how hard you were trying to push it though. I really don't have a clue when this would come into play as there are several things to consider. Temp of water. Current to the LED. Temperature rise in the water after it has been running awhile. I'm sure there is more I just don't feel like thinking about it in that much depth at the moment. Anyhow. Great work with submerging the LED. I think that is the first time I have seen that here.


----------



## Glenn7 (Jan 18, 2009)

saabluster said:


> Since I know of no other way to get those LEDs than to buy the entire light(since they apparently make the LED themselves) that would make for some some very expensive LEDs. I would like to know more about them though. I am very doubtful that they have managed to beat Cree in surface brightness yet. Take the head off the DEFT and just use your hand to focus the DEFT's lens. It is setup to project the beam at close to infinite but try focusing it where the die is visable a few meters in front of you. I am guessing this is what you did with the 8W and is why it seems so intense.



yes i used the DEFT aspheric 

the die in the 8W wouldn't be quite twice the size of a osram GD - but it is tiny and real hard to photograph

also the 8W die is mounted on a little round pedestal about 5mm high - the little round thing next to the die is a hole of which the tiny gold wires from the die go through - you can see this in the photos that i took - and may i say took a guts effort and time to take (think i will patent it ) nah! well it took two hands a spare light a magnifier a zoom lens my teeth and almost had to use my butt cheeks to take the shots 

the photos are full size so you can play with them ie: zoom up to see the wires - enjoy http://picasaweb.google.com.au/glennkath/Eagle8WLED?authkey=4lonB_iH4qw#


----------



## jashhash (Jan 18, 2009)

If this immersion theory is true that means one could theoretically double the throwing power of any maglight mod. I just ordered an aspheric lense and a UCL & now I'm going to try to make the farthest throwing LED light on CPF :naughty:.


----------



## Glenn7 (Jan 18, 2009)

wouldn't H2O boil make steam an expand and burst the UCL lens? (you need antifreez/antiboil)


----------



## saabluster (Jan 18, 2009)

jashhash said:


> I'm going to try to make the farthest throwing LED light on CPF :naughty:.


Good luck trying to beat the DEFT.:nana:


----------



## Ryanrpm (Jan 18, 2009)

saabluster said:


> Good luck trying to beat the DEFT.:nana:



It would be easier to invent transparent liquid tungsten, right?


----------



## jashhash (Jan 18, 2009)

Nah probably wont be able to beat DEFT But maybe come close. Do you think it would be possible to increase the throw of DEFT just by casting a layer of clear epoxy around the LED dome.


----------



## saabluster (Jan 18, 2009)

Ryanrpm said:


> It would be easier to invent transparent liquid tungsten, right?


Uhhh:thinking:.... I don't know if I'd go _that_ far. But close.


----------



## saabluster (Jan 18, 2009)

jashhash said:


> Nah probably wont be able to beat DEFT But maybe come close. Do you think it would be possible to increase the throw of DEFT just by casting a layer of clear epoxy around the LED dome.


I think its possible. I am going to do some tests though to find out. I already have something that I will be doing on my "Art Light" version of the DEFT that will increase the throw and output. So with this new method of "potting" the LED it will be something to see for sure. I can't wait to do some tests now.


----------



## 2xTrinity (Jan 18, 2009)

> I'm wondering if the same thing could be done in a flashlight. If you could somehow glue a cree (with the dome removed of course) to the base of a reflector and then fill the space between the reflector and lense with clear silicone oil. That should provide an improvement in heat dissipation and at the same time give a tighter beam. The downside to this is that everything will have to be thoroughly sealed and frozen in place. The flashlight bezel would have to be sealed with epoxy & the hole in the reflector would need the same treatment.


An easier approach than trying to fill an aluminum reflector with oil, would be to get a total internal reflecting optic, and bond it to the LED (with dome intact) using an index matching fluid. That fluid should ideally have an index of refraction that is in between (specifically, the geometric mean) the index of refraction of the LED glass dome, and the glass or plastic used to make the optic. 

The best thrower you could probably make would be a TIR optic cast into the shape of an ellipsoidal reflector + aspheric lens, all in one piece, simialr to this:






Where the LED in question was actually index-matched to the optic (eg, no air in between the LED dome, and an optic) You'd get the smaller apparent die size, the collimation power of an aspheric lens, and the system would gather light emited into ALL angles -- not just the ones directly forward (as is the case in the current DEFT).

If this index matching were done correctly, the dome would basically "disappear." It is the index-difference between the glass dome and the air around it, which causes the refraction that results in the larger apparent die size. Removing the dome if you plan to flood the device with fluid would be counter-producitve.

Finally, a TIR optic will be more efficeint than the aluminum reflector coatings used in most light as well. However, simply doing this to a TIR optic designed to be used "dry" might not work well -- more than likely, an entirely new TIR optic, explicitly designed to be index-matched to your LED, would need to be used.Also, trying to fill an entire light with oil (rather than just a small vacancy between the dome of an LED and the TIR optic) would be difficult to do without trapping bubbles, or dust particles inside -- which would destroy the optical transmittance of the light.


----------



## saabluster (Jan 18, 2009)

2xTrinity said:


> Removing the dome if you plan to flood the device with fluid would be counter-producitve.


You are right that a properly designed TIR would be best but nobody here has the capability to make one and you cannot buy one with the features you are talking about. Removing the dome is counter-productive if being run at lower current levels which is why I suggested just potting with clear epoxy to reduce apparent die size. However, if you are trying to push the die to within an inch of its life, which is the only reason to use the fluid as was talked about, you most certainly want the dome off so the die can be cooled by the liquid running over it.


----------



## Bimmerboy (Jan 20, 2009)

saabluster said:


> You are right that a properly designed TIR would be best but nobody here has the capability to make one and you cannot buy one with the features you are talking about.


Actually, one guy here machined his own high quality glass optic which was quite a slick little piece of DIY engineering. I don't remember who it was, but he may have worked in some optical field (ha... get it?... optical field. A little opthamological humor there) for a living, and/or had access to the proper equipment.

If the thread can be dug up, it's possible there's a way to contact him. If there's enough money in it, there's usually always someone willing to do a run of whatever custom item.


----------



## DM51 (Jan 20, 2009)

Bimmerboy said:


> Actually, one guy here machined his own high quality glass optic which was quite a slick little piece of DIY engineering. I don't remember who it was...
> 
> If the thread can be dug up, it's possible there's a way to contact him...


Maybe you mean this thread by Ra?


----------



## Grumpy (Jan 20, 2009)

Could you just carefully sand and or polish the led dome flat or is it not thick enough?


----------



## spencer (Jan 20, 2009)

While sanding it flat you are very likely to knock the dome off.


----------



## Bimmerboy (Jan 20, 2009)

DM51 said:


> Maybe you mean this thread by Ra?



That's the one, DM! Good memory. That saved me a little time as well since I was going to do a search for it.

It would require someone such as Ra actually being able to produce the desired product as described by 2xTrinity (this one sounds a bit complicated), then convincing him it'd be worth his while to do a run. A custom TIR optic for the purposes mentioned here would NOT be cheap! Then again, there are a number of people here who are able, and possibly willing to pay for the _new_ world's longest throwing single LED torch (so, the Databank70 doesn't count... lol).

Yes, this brings the thread even further OT, but man, I'd love to see an optic like that born of the ideas and abilities of those here on CPF.


----------



## saabluster (Jan 20, 2009)

Bimmerboy said:


> Actually, one guy here machined his own high quality glass optic which was quite a slick little piece of DIY engineering. I don't remember who it was, but he may have worked in some optical field (ha... get it?... optical field. A little opthamological humor there) for a living, and/or had access to the proper equipment.
> 
> If the thread can be dug up, it's possible there's a way to contact him. If there's enough money in it, there's usually always someone willing to do a run of whatever custom item.



Yeah I remember that one. Just because he can do a normal optic does not mean he can or wants to do this new optic. I may be wrong but this seems to be a much more difficult task than normal TIR optics. Those optics like the one he made have a hole that goes up the middle and is used to redirect light so that it can be collimated properly. If you fill that in with optical gel or similar it will not work right. So basically it is a no-go on that design as far as I'm concerned.


----------



## Oznog (Jan 20, 2009)

Actually machining cast acrylic into an optic is not all that difficult with a CNC mill and/or lathe.


----------



## saabluster (Jan 20, 2009)

Oznog said:


> Actually machining cast acrylic into an optic is not all that difficult with a CNC mill and/or lathe.


Yes but figuring out exactly what shape it should be is.


----------



## R33E8 (Jan 20, 2009)

I don't think that would be too hard with a bit of experience, math, and some ray tracing software..


----------



## blasterman (Jan 20, 2009)

> This thread belongs in LED rather than LED Flashlights, so I'm mving it now.


 
Considering all I'm seeing is a discussion about flashlight optics, why did you bother? rant/off

For a second I though the topic was about improved LED technology for practical uses - fooled again. I'm also guessing the new LED technology talked about here is just more obnoxious, cold white emitters with a CRI lower than my golf score.


----------



## jashhash (Jan 20, 2009)

Ok I was doing a little more research into this and again did the same experiment only this time using oil. Why oil? Because the refraction index of corn oil is 1.47 which is extremely close to the refraction index of the glass (1.50). Immersing the LED in oil causes the surface area to shrink by an aditional 10%. In all what this means is the apparent surface area of the die is 34% as large as when compared to the non-immersed LED. Basically What I'm saying is that by immersing the LED in oil the light becomes 3x more concentrated. 











By photographing the LED submerged in corn oil, it suddenly becomes clear the shape of the cree ring around die. The oil completely undid the light distortion effect caused by the glass dome. 

I'm wondering what would happen if an LED were immersed in a substance with a refraction index greater than glass. Do you think it would cause the light emmited to become even more focussed than the 1mm die?


----------



## DM51 (Jan 20, 2009)

blasterman said:


> Considering all I'm seeing is a discussion about flashlight optics, why did you bother? rant/off
> 
> For a second I though the topic was about improved LED technology for practical uses - fooled again. I'm also guessing the new LED technology talked about here is just more obnoxious, cold white emitters with a CRI lower than my golf score.


Aside from gratuitous rudeness, what exactly was the purpose of that intervention? If you can't remain civil, stay out of the discussion. If I see another post from you similar in tone to that one, your activities will be suspended.


----------



## SemiMan (Jan 20, 2009)

jashhash said:


> I'm wondering what would happen if an LED were immersed in a substance with a refraction index greater than glass. Do you think it would cause the light emmited to become even more focussed than the 1mm die?



Unfortunately, can't get more focused than the 1mm die at least not effectively as it would violate Etendue http://en.wikipedia.org/wiki/Etendue

Semiman


----------



## 2xTrinity (Jan 21, 2009)

jashhash said:


> Ok I was doing a little more research into this and again did the same experiment only this time using oil. Why oil? Because the refraction index of corn oil is 1.47 which is extremely close to the refraction index of the glass (1.50). Immersing the LED in oil causes the surface area to shrink by an aditional 10%. In all what this means is the apparent surface area of the die is 34% as large as when compared to the non-immersed LED. Basically What I'm saying is that by immersing the LED in oil the light becomes 3x more concentrated.
> 
> By photographing the LED submerged in corn oil, it suddenly becomes clear the shape of the cree ring around die. The oil completely undid the light distortion effect caused by the glass dome.
> 
> I'm wondering what would happen if an LED were immersed in a substance with a refraction index greater than glass. Do you think it would cause the light emmited to become even more focussed than the 1mm die?


The effective die size increases because of the way the light is refracted from the dome. Refraction takes place whenever there is a transition between media of different indices of refraction. 

Whether that is from a high index medium down to a low index medium, or the other way around (eg, glass immersed in some higher index medium) -- the amount of refraction (and also, unwanted reflections from these interfaces) will still be more the greater the index mismatch, in either direction.

The corn oil/glass match there is as good as you can possibly get. 



> Yeah I remember that one. Just because he can do a normal optic does not mean he can or wants to do this new optic. I may be wrong but this seems to be a much more difficult task than normal TIR optics. Those optics like the one he made have a hole that goes up the middle and is used to redirect light so that it can be collimated properly. If you fill that in with optical gel or similar it will not work right. So basically it is a no-go on that design as far as I'm concerned.


In order for the index-matched type of TIR optic to work right, it will necessarily need to be deeper, and have a convex outer surface. This is because the way that RA designed his optic, there is actaully an aspheric lens INSIDE the cylinder where the LED resides.

It is the cutting of this very surface (a convex lens INSIDE a deep cavity) that is probably the most difficult aspect of his build by far. Instead, the collimating lens would need to be on the outside surface -- so that it would be convex on the "window" side where light exits, rather than flat. The idea of this build would to combine the light concentrating power of a large aspheric lens with a much smaller die image. You could probably get throw comparable to one of the mag aspherics, but in a much smaller, more manageable host. 

A lens the size of the DEFT with a TIR system like this would be downright insane -- comparable to good HIDs for apparent throw -- but would also be insanely difficult to pull off...


----------



## saabluster (Jan 21, 2009)

2xTrinity said:


> The corn oil/glass match there is as good as you can possibly get.


Well not quite. The clear plastic that I use for the DEFT lenses has a refractive index of 1.49. Of course this is assuming the glass is 1.50 which it may not. Just depends on what kind of glass they used.



2xTrinity said:


> would also be insanely difficult to pull off...


Thats putting it mildly. I don't think some people realize how hard a task this really is.


----------



## thegeek (Jan 21, 2009)

Edit: I need to start reading the entire thread before jumping in!


Some nice out of the box thinking! I hope something materializes from it.


----------



## Oznog (Jan 21, 2009)

jashhash said:


> Nah probably wont be able to beat DEFT But maybe come close. Do you think it would be possible to increase the throw of DEFT just by casting a layer of clear epoxy around the LED dome.



There will be a mechanical stress issue and the dome may be broken off. 

Also the aluminum surface around it presents problems. As it heats up, it expands differently than the epoxy and may separate. Epoxy and aluminum doesn't make extremely powerful bonds in most cases.


----------



## jashhash (Jan 21, 2009)

> Yes. It happens all the time with Crees without even trying. The glass dome is very easy to knock off. The result is an LED with a reduced apparent die size which does help with throw but along with it comes a tint shift and reduction in lumen output somewhere in the 25-30% range.



You know I was just thinking about that and a thought occurred to me. The dome of a cree LED tends to spread light out coming from the emitter. This is great for a flashlight using a reflector because that means a greater volume of light strikes the surface of the reflector. So when the dome is removed its easy to automatically assume that the flashlight is producing less light using the lux meter for comparison. I'm willing to bet that the amount of light produced is actually the same. Lux is a measure of beam throw and not of total light volume. The only way to verify if this is indeed true is by using an integrating sphere. 

I'm not sure what the tint changes though. Perhaps its like passing white light through a prism and the result is a seperation of colors. Remember that when the dome is taken off all that's left is a layer of silicone with a jaggedy irregular shape. (update) from reading this post: https://www.candlepowerforums.com/threads/144141 it appears that the color tint, and output loss was a result of cleaning the silicone off the die and not by the removal of the dome. I'm guessing that through the washing process he may have damaged part of the die, removed a layer of phosphor, or changed the phosphors surface structure.


----------



## comozo (Jan 21, 2009)

Flourinert is clear


----------



## saabluster (Jan 21, 2009)

Oznog said:


> There will be a mechanical stress issue and the dome may be broken off.
> 
> Also the aluminum surface around it presents problems. As it heats up, it expands differently than the epoxy and may separate. Epoxy and aluminum doesn't make extremely powerful bonds in most cases.



Yes there is a CTE mismatch but I don't think it matters in this case. For one it does not matter if the epoxy has a perfect grip on the aluminum. Even if it separates slightly it is not in the beam and will not affect light output. It really is a non-issue with my lights as the pills I make for the DEFT are already covered in epoxy and the clear can adhere to the white epoxy I use.
Also I am not in the least bit concerned about the dome popping off because the flexibility of the gel can absorb any stress caused by the CTE issues. We will find out though. I am making myself a pill that is encased in clear to test with tommorow.


----------



## Gryloc (Jan 22, 2009)

I just wanted to chime in and mention that the 25-30% loss of light when the dome is removed was measured using devices very similar to an integrating sphere. Saabluster tested his using a ceiling bounce test, and I did similar tests using an integrating "box" that I made. Even though these devices may not be accurate when finding the exact lumen output, they are excellent when making comparative tests (before and after tests) since they do not vary any between tests.

Actually, I just did another unfortunate test on an LED that has a large beam angle: the MC-E. It was a pleasant neutral white emitter I had in a flashlight. I measured the lux when it was healthy, but after some "messing around" with different reflectors, I accidentally got the glass dome wedged into the opening on a plastic reflector, so when I pulled away the reflector, I took the dome with it. I tested the LED soon after because I was worried about losing total light output, and sure enough, I did lose about 30% of the total light. Now the neutral MC-E has about the same efficiency as the older cool white Luxeon K2 emitters. 

So, I do not recommend removing the die unless you are really striving for throw. Even then, you may only see a 30% increase in trow when using a reflector (brighter, tighter spot), but then you find that the hotspot brightness is no brighter than the hotspot of an un-modified emitter (which is maybe slightly larger). So, all you see is a decrease in hotspot size and an overall decrease in total lumens.

I am interested in seeing how the large TIR optic would work. Didn't Inova use a very long, deep TIR optic in one of their lights? What if you start by mating that optic with the R2 XR-E or Sunlite emitter with oil? Just dont forget what saabluster said earlier: you are messing with the hard work of the researchers. You will have to put quite a lot of time into research to find the perfect materials, optical design, and mechanical design to seal this potentially slimy mess! Luckily, lots of flashlights come as being somewhat waterproof, so keeping the fluids in might be simple after all. Now keeping the fluid away from the battery may be a different story!

I wish there could be more info on the "Sunlite 8W" LED emitter. I am wondering about the efficiency of the emitter compared to an overdriven XR-E. Dont forget the Cree XP-E (R2), the Lumileds TFFC Rebel (0100) and TFFC K2 (0200), and the Seoul P4 (U2) emitters are available for some decent over-driving. These emitters have the desirable lambertian beam pattern so you do not have to deal with the tricky optic and metal ring found on the XR-E. The domes on these emitters do magnify the die some, but they could be a better way to start. Actually, the dome on the Rebel can be removed (no bond wires -yay) so you can access the die directly (dry, no silicone goo found here!). Good luck all! Could this be continued in a more dedicated thread? Just curious...

Cheers,
-Tony


----------



## jashhash (Jan 22, 2009)

Thanks for the helpful insight, I wasn't aware that the light measurement was taken from a ceiling bounce. Now it's clear that the output is diminished but I'm still confused as to what's causing the efficiency loss.


----------



## 2xTrinity (Jan 22, 2009)

jashhash said:


> Thanks for the helpful insight, I wasn't aware that the light measurement was taken from a ceiling bounce. Now it's clear that the output is diminished but I'm still confused as to what's causing the efficiency loss.


In the case of the XR-E, notice how when the dome is intact, the only real part that is visible is the die itself, which is magnified, followed by the "cree ring" at very oblique angles. With the dome removed (and especially so when NOT immersed in an index matching fluid) the cree rings, and all sorts of other device features are now visible. Now instead of almost all the lumens from the die making it out, light will actually reflect off the interface between the gel and the air. Reflections at interfaces are minimized when the light striking the surface is at normal incidence. With a dome -- ALL THE light from the LED is striking the glass-air interface head-on, so basically almost all of it makes it back out. This is the real reason for the dome, magnification of the die is an unwanted side effect. With a flat interface, the vast majority of the light will strike the dome at a very oblique angle, and a much of it will reflect back into the device, rather than making it out. This means more light will end up bouncing off the cree ring, or bouncing onto the phosphor for a second time (causing the purplish/brownish "tint shift") Increased reflection or scattering losses of 20%+ does not sound unreasonable.

However, with an index matching gel -- my thought is that there will not be any reflection between the gel-air interface, because there will BE no interface anymore. The difficult part would be coupling the LED to an optic that will actually reflect the light at the correct angles. Note this is not an easy problem at all. An easier approach would be to filling an aluminum reflector with a gel (rather than try to make a TIR optic with the right critical angles) actually would be an easier way to pull this off. It wouldn't be AS efficient as an ideal TIR optic, but that would be almost impossible to home-brew.

The whole thing that actually got me started on this train of thought was shearing the domes off of some MC-Es uninentionally. I though of the gel idea as a way to possibly salvage them.


----------



## jtr1962 (Jan 22, 2009)

Gryloc said:


> I just wanted to chime in and mention that the 25-30% loss of light when the dome is removed was measured using devices very similar to an integrating sphere. Saabluster tested his using a ceiling bounce test, and I did similar tests using an integrating "box" that I made. Even though these devices may not be accurate when finding the exact lumen output, they are excellent when making comparative tests (before and after tests) since they do not vary any between tests.


I tested this also. See here. Results were 24% less light with the dome removed, about the same as the results you and saabluster got.


----------



## saabluster (Jan 22, 2009)

jtr1962 said:


> I tested this also. See here. Results were 24% less light with the dome removed, about the same as the results you and saabluster got.


I had not seen that test before. Nice to see that our "crude" testing methods matched up fairly well with your tests. Thanks


----------



## jashhash (Jan 22, 2009)

Do you think that covering the dome with epoxy would have the same effect as taking it off. Do you suppose that the total output would be reduced by 25%


----------



## 2xTrinity (Jan 22, 2009)

jashhash said:


> Do you think that covering the dome with epoxy would have the same effect as taking it off. Do you suppose that the total output would be reduced by 25%


Not necessarily. I beleve the big problem is having a flat gel-air interface directly above the die -- most of the light in that case will strike it at an oblique angle, causing a lot of reflection losses. This reflected light will strike the substrate around the LED, which is not a particularly good reflector -- hence lumen losses. Not only that, the fact that the dome must be forcibly removed means the surface is very uneven, which makes things worse.

If you were to use something like an aluminum reflector, and filled it completely with an oil or epoxy uniformly such that it covered the dome -- you wodln't have an abrupt interface causing reflection losses. and you wouldn't have a refractive surface magnifying the dome. Keep in mind the effective focal point will change to the LED's actual location, not to where the die-image _appears_ to be. This is a very diffcult proposition to actually pull off.

Also, if the interface between your epoxy that you're filling in with, and the air is no so close to the LED, the light won't be striking it at as shallow of an angle, and much of the "back reflected" light will strike a reflector surface (rather than a random useless cavity or aluminum ring) and eventually make it out of teh flashlight. There may still be some lumen loss, but it should be a lot less than shearing the dome off.


----------



## xpea (Jan 24, 2009)

3 pages of interesting discussion, mainly about optics, but still no news about emitter efficiency increase...

So what expect after Cree R2 in 2009 ? status quo or some new jump ? anyone with roadmap information from SSC, Limiled, Osram or Cree ?


----------



## saabluster (Jan 24, 2009)

xpea said:


> 3 pages of interesting discussion, mainly about optics, but still no news about emitter efficiency increase...
> 
> So what expect after Cree R2 in 2009 ? status quo or some new jump ? anyone with roadmap information from SSC, Limiled, Osram or Cree ?


I would expect Cree to be releasing their new single die 1000lm LED this year. R3 bin Crees seem to be just around the corner as well.


----------



## HarryN (Jan 24, 2009)

deleted


----------



## Ryanrpm (Jan 24, 2009)

saabluster said:


> I would expect Cree to be releasing their new single die 1000lm LED this year. R3 bin Crees seem to be just around the corner as well.



Here is the quote from Cree's website: "A single-die LED, driven at four amps, produced 1,050 lumens in cool white and 760 lumens in a warm-white version. Efficacy of the cool-white LED was 72 lumens per watt and 52 lumens per watt from the warm-white device."

So to achieve this 1000 lumens, the chip has to be driven at 4 amps. Is this possible with todays drivers and batteries? I wouldn't know, but I think you would know saabluster........since you are creating a 1000 lumen Black Tie.

What kind of battery configuration would be needed to produce 4 amps?


----------



## baterija (Jan 24, 2009)

Ryanrpm said:


> So to achieve this 1000 lumens, the chip has to be driven at 4 amps. Is this possible with todays drivers and batteries? I wouldn't know, but I think you would know saabluster........since you are creating a 1000 lumen Black Tie.
> 
> What kind of battery configuration would be needed to produce 4 amps?



Single IMR 18650
Any of the P7 driver/battery combinations should also give you similar brightness to a P7/MC-E in a single die even though it's not driven to max spec.


----------



## Gryloc (Jan 24, 2009)

Do not forget that the P7 and MC-E uses 4 dies, not one. A single die emitter would be like your XR-E, Seoul P4, or Luxeon emitter (not LuxV). The single die would mean a small light source (hopefully) with no gaps that would cause artifacts (like the P7 and MC-E). This single die 1000 lumen monster sounds nice. How sure are you that it will be released this year? Where did you hear this? Thanks!

-Tony


----------



## saabluster (Jan 24, 2009)

Ryanrpm said:


> Is this possible with todays drivers and batteries?
> 
> What kind of battery configuration would be needed to produce 4 amps?


This is no problem for drivers that a readily available to anyone here. Running 4 amps can be accomplished by several different battery chemistries. The new IMRs come to mind as the lastest but NiMHs are also very capable of producing this amount of current. Its all how you set them up. In short there are too many ways to accomplish supplying 4 amps than I have time or desire to type.


----------



## saabluster (Jan 24, 2009)

Gryloc said:


> How sure are you that it will be released this year? Where did you hear this? Thanks!
> 
> -Tony


I don't have any insider info or anything. Just going by Cree's own word. This is what Cree said when they released the press release for that LED back in Sept. 07. "Cree says that historically its R&D demonstrations generally have been commercialized within 12 to 24 months." Cree is very good about doing what they say they will. It will be 2yrs since that announcement this Sept. So I'm just adding two and two.


----------



## 2xTrinity (Jan 24, 2009)

1000lm from a single die sounds almost unbelievable if the die is the same 1x1mm size as in the XR-E. Does anyone know if it is in fact a larger die? That said, even if it is a larger die, that is still a more elegant solution to produce throw than trying to image four closely packed dice, and somehow "blur out" the gap between the dice.

If this actually does enable 4x the surface brightness of the current XR-Es, that means that even relatively small lights (eg 1x18650 size) can have awesome throw. Also, unlike incan throwers, an LED thrower could have an otpion to run at more like 1 amp continuously, with a "burst" mode of 4 amps. A small light drawing that kind of power won't hvae a long runtime, but unlike say incan hotwires (which it looks like LEDs are increasingly beginning to challenge for throwing capability) the LED can be dimmed without losing any efficiency.

If that much power does come out in a single emitter, I will definitely buy, or possibly build myself, an EDC light with the following features:


Single 18650 or 18500 battery-powered light, where the light is not much larger than the battery itself. Similar to most current AA EDC lights but slightly fatter. Then run the high current LiMn chemistry
Interface like the LF3XT -- click-and-hold to ramp up or ramp down brightness continuously anywhere from 0.1 to 1000 [emitter] lumens (absolutely MUST use a logarithmic taper with this kind of range...)
Optic or reflector that produces broad but intense hotspot, with gradual transition to spill, and narrow spill angle. Not a super thrower, or total flood, but something that can be usable up close, or at a reasonable distance
A 1x18500 light could be built today with an MC-E, but it would only be suitable for a pure flood application. A 1000 lumen light with the same beam profile as a XR-E on the other hand would be a lot nicer.


----------



## saabluster (Jan 24, 2009)

2xTrinity said:


> 1000lm from a single die sounds almost unbelievable if the die is the same 1x1mm size as in the XR-E. Does anyone know if it is in fact a larger die?


Yes it is larger than the XR-E's die. Off the top of my head it was like 1.5- 1.7mm square. Don't have time at the moment to dig up the quote.


----------



## rushnrockt (Jan 26, 2009)

I feel almost like this is off-topic here, but some interesting products from truly multi-die field

http://www.edison-opto.com.tw/products_detail.asp?category=1&cno=225

Here we have a 5W, 10W, 15W, 20W, 50W and even 100W monstrosities with up to ~6500 lumen output, which is pretty impressive as far as efficiency goes for a multi-die setup. Now all I would like to figure out is where to get the samples


----------



## mejesster (Jan 28, 2009)

Another quick little item:
http://blogs.zdnet.com/green/?p=1632
Cree LEDs to be installed in the Pentagon


----------



## Nereus (Jan 29, 2009)

Ryanrpm said:


> Here is the quote from Cree's website: "A single-die LED, driven at four amps, produced 1,050 lumens in cool white and 760 lumens in a warm-white version. Efficacy of the cool-white LED was 72 lumens per watt and 52 lumens per watt from the warm-white device."


 
Let's add some straightforward maths here: 1050 lumens and 72 lm/W -> that is 14,6 W. Four amps and 14,6 W -> that is 3,65 V forward voltage. That's _very_ low value for such a high current. I would have expected something like 4,5 volts forward voltage.

- N


----------



## kongfuchicken (Jan 29, 2009)

Read this on /. this morning.
It's not much at this moment still and like much of the vaporware (or in this case, vapor-process technology?), it might not see the light of day for years but here's some hope:
breakthrough

Summary:
New manufacturing method is invented that solves a problem related to thermal stress during the making of InGa dies and will result (eventually) in prices orders of magnitude cheaper than currently.


----------



## HarryN (Jan 31, 2009)

I had the opportunity this past week to see some presentations at the Photonics West Conference in San Jose, CA. I did not attend all of them of course, but one slide really caught my eye in a Lumiled's presentation.

Now of course, this is research lab work, so not an LED you can buy yet, but they were showing Vf's below 3 volts at 1,000 ma in a 1 x 1 die, and (I think) Vfs below 3.5 V at 2,000ma - not exactly certain. There was much more of course, more or less similar to the work and goals of others in terms of efficiency, but the very low Vf quite impressed me.


----------



## 2xTrinity (Jan 31, 2009)

HarryN said:


> I had the opportunity this past week to see some presentations at the Photonics West Conference in San Jose, CA. I did not attend all of them of course, but one slide really caught my eye in a Lumiled's presentation.
> 
> Now of course, this is research lab work, so not an LED you can buy yet, but they were showing Vf's below 3 volts at 1,000 ma in a 1 x 1 die, and (I think) Vfs below 3.5 V at 2,000ma - not exactly certain. There was much more of course, more or less similar to the work and goals of others in terms of efficiency, but the very low Vf quite impressed me.


At the wavelength used in the typical white LEDs (350nm) optimum Vf will be 2.8V, corresponding to the 2.8eV energy of a photon at that wavelength. Any higher Vf than that will necessarily represent power inefficiency.

Even most of the latest XR-Es I've been able to get my hands on recently have been ~3.3V @ 1A. Whereas a year and a half ago, Cree LEDs were more like 3.8V at that current. And they produced fewer lumens at that current.

Invariable some photons will be emitted at longer wavelength, and some at a shorter wavelength -- this is why an LED can be "turned on" at below 2.8V, but it is less efficient to do so (this is the explanation for the efficiency "peak" at 20mA current for a Cree XR-E, for example -- this correspond to feeding the LED _just_ enough voltage that it might emit at its optimum wavelength). 

Below 3V at 1000mA is excellent, almost as low as it can possibly get. Very intersting indeed.


----------



## lyyyghtmaster (Feb 3, 2009)

I assume you meant 450nm, not 350nm for a Cree, right?  

Luminous Devices' Phlatlight ( http://www.luminus.com/content1462 ) comes to mind as a recent development. Though obviously not good for throw, "The CBT-90 is capable of delivering over 1,750 lumens _from a single 9mm2 monolithic chip._" (italics mine). That (and their 4-chip CBM-360) would make some excellent flood monsters methinks! (I don't have any ties to this company, just found their products interesting!) Unfortunately these products seem to cost about as much per mm2 as any other HBLED. :shrug:


----------



## octobersky (Jul 31, 2011)

2xTrinity said:


> The best thrower you could probably make would be a TIR optic cast into the shape of an ellipsoidal reflector + aspheric lens, all in one piece, simialr to this:



Who makes this optic and where can I get more information about it? Thank you.


----------



## Curt R (Aug 1, 2011)

That optic was used in a light and was discontinued about four
or five years ago. It made the light tooooo long as compared to
the competition. I think it was an Inova LED light, not sure thou.
However Emisive Energy sold the LED flashlight line to Nite-ize and
all Inova lights are made in China now. Since that optic was an 
in-house design and discontinued, it becomes a dead end.

Curt


----------



## arpy (Aug 2, 2011)

Concerning TIR Optics: Surefire still use them in some premium lights, because they shape the beam in a better way than a reflector of the same size could. The upcoming Surefire Invictus will have a TIR lens, if you believe the previews. My Surefire Kroma has one too, but it's not a very bright light, so it's a little in vain


----------

