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Thread: Experiments in LED encapsulation

  1. #1

    Default Experiments in LED encapsulation

    This is something I have been wanting to do a while and bought the material quite some time ago do a project using quantum dots but those will have to wait. I have been wanting to encapsulate my own LEDs to do experiments on what the absolute best setup is for my aspheric setup. I have not had time yet to run any tests but I got some pictures today and thought I'd get it started. I am using a high grade optical silicone meant for encapsulating LEDs. This is not Home Depo material here. I removed the domes of both LEDs and scraped off the silicone gel down to the silicone layer that holds the phosphor.


    From left to right we have an XR-E with an acrylic optic applied over the encapsulant, a regular XR-E, and an XR-E with only silicone encapsulant. Notice how you can already see the LED die on the one with the acrylic optic.


    See the change in die size?






    I'll have to get to the tests at a later date.
    Last edited by saabluster; 11-02-2009 at 12:11 AM. Reason: title change to better reflect intent

  2. #2
    Flashaholic*
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    Default Re: DIY LED encapsulation

    Sweet.

  3. #3
    Flashaholic* bshanahan14rulz's Avatar
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    Default Re: DIY LED encapsulation

    why the dome? Why not just a flat layer of silicon encapsulant? That would make your die appear even smaller, right?

    (btw, I'm trying to make a P60 drop-in, just waiting to find a suitable chunk of copper that would put the die in the focal point of the smo reflector. It would be nice to encapsulate the die, only for protection, since my whole reason for doing this was decreasing the die size and putting more light to the reflector. I was just wondering if you've done any lumens testing of LED with and without dome. It is common knowledge that an LED will dim and change colors when you remove the dome and the gel. However, I don't believe it at all, since mine didn't change colors and definitely appears brighter (smaller point). right now, I'm not able to afford to buy any parts, hence the wait for a suitable chunk of metal to show up, but I was mainly curious if you've noticed any degradation of light output or tint. Oh, and I guess I'll close my parenthesis...)

  4. #4

    Default Re: DIY LED encapsulation

    Quote Originally Posted by bshanahan14rulz View Post
    why the dome? Why not just a flat layer of silicon encapsulant? That would make your die appear even smaller, right?

    (btw, I'm trying to make a P60 drop-in, just waiting to find a suitable chunk of copper that would put the die in the focal point of the smo reflector. It would be nice to encapsulate the die, only for protection, since my whole reason for doing this was decreasing the die size and putting more light to the reflector. I was just wondering if you've done any lumens testing of LED with and without dome. It is common knowledge that an LED will dim and change colors when you remove the dome and the gel. However, I don't believe it at all, since mine didn't change colors and definitely appears brighter (smaller point). right now, I'm not able to afford to buy any parts, hence the wait for a suitable chunk of metal to show up, but I was mainly curious if you've noticed any degradation of light output or tint. Oh, and I guess I'll close my parenthesis...)
    I made it the shape of a dome because the LED is going to be aiming at an optic and I wanted the escape surfaces to be as perpendicular as possible to reduce the chance of internal reflection. Don't know if it is a success or not yet as I have not done any testing. BTW removing the dome of an XR-E does cause a loss of lumens of about 30%. The fact that the beam is smaller does not mean it is bright- just small. You may have pulled yours off very cleanly and that helped keep it from changing tint.

    Heres hoping it rains copper near you some time soon.

  5. #5
    Flashaholic* bshanahan14rulz's Avatar
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    Default Re: DIY LED encapsulation

    Quote Originally Posted by saabluster View Post
    I wanted the escape surfaces to be as perpendicular as possible to reduce the chance of internal reflection
    Ahh, makes complete sense! dome ensures light hits the intersection "plane" of gel and air at close to perp for maximum light transmission and minimal internal reflection, so it's all about finding the perfect combo of small source but also high light extraction percentage. Ok, how bout this one: I've heard that the metal ring actually is meant to reflect light forward. Is this like, an afterthought, or a gimmick to increase the final numbers for total emitter lumens? as this light doesn't seem like it's very usable, and usually just makes a different-color ring around the beam. If you encapsulated it w/o the ring, though, you'd have to make the dome more domed, hence larger die image though, right? ok, so you don't have to answer that one after all.

    Quote Originally Posted by saabluster View Post
    BTW removing the dome of an XR-E does cause a loss of lumens of about 30%.
    Ah, dern. Well, 30% of an R2 isn't too bad, I guess. Do you think if I get this LED spaced right, it will throw better than a complete cree LED with the same SMO reflector?

    Quote Originally Posted by saabluster View Post
    Heres hoping it rains copper near you some time soon.
    Thanks! I have found some cheapo server heatsinks, stacked fins, soldered onto 5mm thick copper, might try to find a way to get at that copper. Don't have a torch, so desoldering is out of the question. I sure would like to get my hands on some of those solid, 1pc copper skivved sinks that we replaced these with

    Ever thought about developing a TIR mold and just encapsulating the LED and make the optic at the same time? Although from the sound of it, this encapsulant you're using is top-o-the-line $$$ stuff..
    Last edited by bshanahan14rulz; 10-29-2009 at 11:25 AM.

  6. #6

    Default Re: DIY LED encapsulation

    Quote Originally Posted by bshanahan14rulz View Post
    Ok, how bout this one: I've heard that the metal ring actually is meant to reflect light forward. Is this like, an afterthought, or a gimmick to increase the final numbers for total emitter lumens? as this light doesn't seem like it's very usable, and usually just makes a different-color ring around the beam.
    It's no gimmick. In a fixture that mixes or diffuses the light the ring is a non-issue and the added light is a good thing. They did not have just flashlights in mind when they designed the XR-E.

    Quote Originally Posted by bshanahan14rulz View Post
    If you encapsulated it w/o the ring, though, you'd have to make the dome more domed, hence larger die image though, right? ok, so you don't have to answer that one after all.
    Well you don't have to make it more domed. I personally want the surface as far from the die as possible for the same reason I am shooting for a flatter surface. I would not need to do this if the die was a true point source.

    Quote Originally Posted by bshanahan14rulz View Post
    Ah, dern. Well, 30% of an R2 isn't too bad, I guess. Do you think if I get this LED spaced right, it will throw better than a complete cree LED with the same SMO reflector?
    Quite possibly yes. That is if you are comparing the modified XR-E to a normal XR-E. I would not expect it to throw more than an XP-E though. Only one way to know for sure though.


    Quote Originally Posted by bshanahan14rulz View Post
    Ever thought about developing a TIR mold and just encapsulating the LED and make the optic at the same time? Although from the sound of it, this encapsulant you're using is top-o-the-line $$$ stuff..
    Yes. Many times. This is more of a task than I have time for right now though.

  7. #7

    Default Re: DIY LED encapsulation

    how about eliminating the dome all together and use a TIR optic and index match (well, close) between the dome and the lens?

  8. #8

    Default Re: DIY LED encapsulation

    Quote Originally Posted by Gomer View Post
    how about eliminating the dome all together and use a TIR optic and index match (well, close) between the dome and the lens?
    Because the TIR optic would have to be designed specifically for that. There is no such thing as far as I know.

  9. #9
    Flashaholic* lolzertank's Avatar
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    Default Re: DIY LED encapsulation

    Would TFFC Rebels be better for doing this? After all, they don't have any fragile bond wires to break like the XR-Es. I guess a ring could be added to focus the light.
    Awesome! I just got the Luxoulree Z4 bin XD-Q! Wait... are you saying they released the Z5 bin the day after I bought it?

  10. #10

    Default Re: DIY LED encapsulation

    Quote Originally Posted by lolzertank View Post
    Would TFFC Rebels be better for doing this? After all, they don't have any fragile bond wires to break like the XR-Es. I guess a ring could be added to focus the light.
    No they would not be any better than the XR-E as it is really easy to get all the gel off the XR-E die without damaging the phosphor. Seems like it is fairly easy to pull off the phosphor layer on the rebels. I'm just going by memory from others experience. I don't have any experience destroying rebels. In any case the XR-E can handle more power so it is my preferred platform.

    What do mean a ring could be added?

  11. #11
    Flashaholic* lolzertank's Avatar
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    Default Re: DIY LED encapsulation

    Quote Originally Posted by saabluster View Post
    What do mean a ring could be added?
    I'm talking about the reflective ring on the XR-E, but since you're going to stick with XR-Es, it doesn't really matter.

    Hoping for an XR-G!
    Awesome! I just got the Luxoulree Z4 bin XD-Q! Wait... are you saying they released the Z5 bin the day after I bought it?

  12. #12

    Default Re: DIY LED encapsulation

    Quote Originally Posted by lolzertank View Post
    I'm talking about the reflective ring on the XR-E, but since you're going to stick with XR-Es, it doesn't really matter.
    Oh were you talking about adding a ring to the Rebels?



    Quote Originally Posted by lolzertank View Post
    Hoping for an XR-G!
    Me toooooo. Want to go camp outside Cree together and protest until they release one?

  13. #13

    Default Re: Experiments in LED encapsulation

    I have now taken some tests both empirically and with my lux meter. I installed each one in a DEFT and tested side by side. The LED that had the silicone alone(the one on the star) did horrible enough by eye that I didn't even bother testing with the meter. This does not mean that the encapsulation method is to blame however as it was an old LED of unknown bin or provenance. I think it was a Q5 WC but the output from it was feeble so there may have been some abuse imparted upon it by myself sometime in the past.

    Anyway I took the lights outside and had a normal DEFT as the control. The normal DEFT and the acrylic modified LED were both R2 WHs. I am stunned to say it but the one with the acrylic threw significantly farther. Judging by my eye I guessed the modified XR-E had just slightly less than twice the intensity of the normal XR-E! I swapped the batteries from one to the other to make sure that was not a factor. No change.

    I ran inside and used my light meter to pin down just what the difference was. I did the measurements from about 15' away. The relative throw measurements for them are as follows.

    Unmodified XR-E DEFT- 20
    Acrylic/silicone encapsulated XR-E in DEFT- 34

    This matches exactly what my eyes saw outside. That means I now have a system for an aspheric that beats the lab designed result! Now I need to combine this with the method of reducing the ceramic backer I created and mount it to a heat-pipe. Should be one heck of an LED.

    Now if I can just get those quantum dots from our friend here. You know who you are.

  14. #14

    Default Re: Experiments in LED encapsulation

    Well it just gets better and better folks. I think I have made the best LED you could have. In playing with it more I have found it has some unique qualities that are not found in other LEDs. Some people may be aware of how the tint can change on XR-Es when the dome is removed. We don't know for sure why this is but the tint has also changed on my modified XR-E. The strange and wonderful thing is that it has shifted more to the red side. This is the warmest cool white LED I can ever remember seeing. The CRI seems to have improved as well. I took it outside without the head so that it was full flood and it was a thing to behold. It was the best beam I have ever seen from a bare LED. Better rendering of the reds in the fallen leaves was noticeable. One other thing that changed about the beam is the variance in tint dependent on angle of emitted light. The unmolested XR-E has more blue in the center of the output and gets warmer as the angle increases. Not the modified one. Smooth tint throughout the spacial distribution.

    I created this as an experiment to create a better LED for aspherics but it works just as well with a reflector. The beam is much tighter and more intense with an incredible tint. It is what I call vanilla white. The only down side is the Cree rings have been "enhanced" in the new setup. With a reflector an orange peel should handle that just fine and I figure on the one for the aspherics I can use a flat black paint on the ring to make it disappear.

    I am thoroughly blown away by these results. I didn't expect it to be even half as good as it turned out to be. Now I need to do some more to make sure this wasn't a fluke.

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    Default Re: Experiments in LED encapsulation




    Saab, if you manage to get this process down pat, would it be possible for you to sell some of these modified LEDs? I'm currently building an aspheric, and I'd love to get my hands on a couple of those!
    Finning does help dissipate heat. This is why the fins are removed before cooking fish. Otherwise it will throw off the heat and not reach the proper cooking temperature. --Duglite

  16. #16

    Default Re: Experiments in LED encapsulation

    Quote Originally Posted by Th232 View Post



    Saab, if you manage to get this process down pat, would it be possible for you to sell some of these modified LEDs? I'm currently building an aspheric, and I'd love to get my hands on a couple of those!
    The results are so good I am seriously considering offering some for sale. I need to do some more testing to be sure it is fairly reliable but it did wonderfully at 1500mA for about 35 minutes. More testing is obviously in order though. Next I will try an AR coated glass optic. That may actually allow me to have more output than the stock XR-E as my light meter tests suggested I was only losing about 5-6% in total lumens using the acrylic.

    Can you imagine an R3 bin XR-E with a super tiny die size and great tint. I'm salivating just thinking about it.

  17. #17
    Flashaholic* Gryloc's Avatar
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    Default Re: Experiments in LED encapsulation

    Saabluster,

    Nice work with encapsulating the XR-E emitters. I have been watching this in excitement to see what happens when a flashaholic has control over the emitter dome shape. BTW, how have these mods affected overall lumen output compared to before the mod? I personally lost domes off of two Rebel 0100 emitters and it seems like the phosphor was perfectly intact and the LED operational. The K2, and the Cree products still use bond wires that would be torn after removing the die. Hopefully, regardless of the emitter used, domes will not have to be removed in your experiments. Clean silicone domes of the XP-E, XP-G, and Rebel might disappear when you goop your silicone gel over top of it (so dome removal may be unnecessary).

    So, I was just wondering why the encapsulated XR-E (dome removed) with the acrylic lens did better than the one without. Is it an issue with different indexes of refraction? Is it because the acrylic lens has a smoother surface?

    You may have stumbled on something good for aspheric lens users, but I think before you should start selling these in large quantities, you should do more testing. I think that members would love to see comparisons between 3-4 new XR-E emitters from the same batch. Who knows, maybe your modded emitter without the lens degraded some, and if in better shape, could have perform the best. Having new emitters that perform the same from the start will help produce more conclusive tests in a more scientific fashion. (I understand the preliminary experiments with spare XR-Es). BTW, does the Deft use a high quality current regulator so even big changes in LED forward voltage will not affect output? I was just wondering.

    Between the two modified XR-E emitters, I guess I do not understand why they are so different. Why not remove the ring and then re-encapsulate the emitter? Why not re-encapsulate a Rebel, XP-E or XP-G? I see that the consistency of the optical grade silicone gel causes your "dome" to sag before it cures, but why not let gravity aid you? I do not know its viscosity or its values for surface tension, but maybe when held upside down, a dome might form a geometric shape in your favor (parabolic, spherical, elliptical, or catenary). If you are going for flatness, then why not temporarily fix it to the center flat spot of an old brushless PC cooling fan and let centripetal forces level off the top of the dome some? If the viscosity is high enough and you make the fan spin slow enough, you may get a very flat surface. As you spin it faster it may begin forming a parabolic dip in the center (like what happens with those experimental spinning mercury mirrors). You have a lot of control over the shape of this dome; that is awesome.

    If that acrylic lens is the ultimate solution, then why not take an old Cree XR-E metal ring (or a spacer with the same height) and fix it above a Rebel, XP-E, or even XP-G then fix on the acrylic lens? Maybe a modded XP-G would produce a projected beam (in the Deft) of the same size as an un-modded XR-E from your existing setup (I am being hopeful here).

    I am just asking that you try different setups with other emitters. We all bow to you since you have the optical grade silicone gel and experience. I like the XR-E, but have always been doubtful to the metal ring from the optical standpoint (I understand the mechanical purposes). If you can make a new dome over the tiny Rebel, XP-E, and XP-G, you might be able to shape the dome to do the same thing that the glass dome on the XR-E did, or you may be able to shrink down the apparent die size (flatten the dome) without sacrificing the total lumen output.

    I always found the tint shift interesting. I also worry that the tint shift, while being pleasant to the eyes, may be bad for efficiency or overall longevity. It seems like a major change happens when the tint shift occurs, and it could be a bad change. Does it mean that more blue light is internally reflected back to the phosphor coating to produce reds
    (due to the change in index of refraction), or does it maybe affect how heat is removed from the top of the light which affects the efficiency of the phosphors?

    Again, good job. Thanks for your patience with my numerous questions mixed in my post. Your experiment is intriguing, as many are afraid of working at the emitter level when doing modifications and experiments. If I had the tools and resources, I would have acted on my own emitter mods. For example. You could theoretically can cut rebel emitters down (the ceramic substrate) without affecting the etched traces to position the four dies tightly together so they almost touch (electrically, they could touch if you plan on wiring the dies in parallel). Just re-encapsulate them (or not if you cut cleanly) and this could equate into a quad TFFC die emitter. Its not a practical mod (with the MC-E, P7, and SST-50 out there), but I dream that it could be done.

    Cheers,
    -Tony

  18. #18

    Default Re: Experiments in LED encapsulation

    Quote Originally Posted by Gryloc View Post
    Saabluster,

    Nice work with encapsulating the XR-E emitters. I have been watching this in excitement to see what happens when a flashaholic has control over the emitter dome shape. BTW, how have these mods affected overall lumen output compared to before the mod? I personally lost domes off of two Rebel 0100 emitters and it seems like the phosphor was perfectly intact and the LED operational. The K2, and the Cree products still use bond wires that would be torn after removing the die. Hopefully, regardless of the emitter used, domes will not have to be removed in your experiments. Clean silicone domes of the XP-E, XP-G, and Rebel might disappear when you goop your silicone gel over top of it (so dome removal may be unnecessary).
    As I mentioned in my last post lumens are down about 5-6% but it's hard to be sure since the spacial distribution is much different and I do not have an IS.
    I think you may have misunderstood what I did here. I did remove the dome and removed the gel that sits under the dome in its entirety. I took it all the way down to the phosphor impregnated silicone elastomer(note not the same thing as the gel) that Cree uses to coat the die with. Then I applied my silicone on top. Domes do have to be removed or it will not work. Also I have never had a Cree fail from pulling the dome off. The bond wires are fairly tough. I even picked at one to see how strong it was.

    Quote Originally Posted by Gryloc View Post
    So, I was just wondering why the encapsulated XR-E (dome removed) with the acrylic lens did better than the one without. Is it an issue with different indexes of refraction? Is it because the acrylic lens has a smoother surface?
    As I said I don't know what the condition of that LED(silicone only) was prior to the test. It was just sitting in the drawer missing a dome so I used it. This was just a preliminary test to see what would happen to the shape of the beam and get an idea if my ideas for encapsulation would work. There could be issues with index matching to the atmosphere and there may not be. I will not know until I can try it again with a know good LED. The one with the acrylic was known to be good.

    Quote Originally Posted by Gryloc View Post
    You may have stumbled on something good for aspheric lens users, but I think before you should start selling these in large quantities, you should do more testing. I think that members would love to see comparisons between 3-4 new XR-E emitters from the same batch. Who knows, maybe your modded emitter without the lens degraded some, and if in better shape, could have perform the best. Having new emitters that perform the same from the start will help produce more conclusive tests in a more scientific fashion. (I understand the preliminary experiments with spare XR-Es). BTW, does the Deft use a high quality current regulator so even big changes in LED forward voltage will not affect output? I was just wondering.
    As I said before more testing is definitely in order. This is also not just good for aspherics as the beam was significantly better for a reflector I used with it. The DEFT's output can change based on Vf and I know that so I will find a more accurate means of testing on the next round. This was just a proof of concept.

    Quote Originally Posted by Gryloc View Post
    Between the two modified XR-E emitters, I guess I do not understand why they are so different. Why not remove the ring and then re-encapsulate the emitter? Why not re-encapsulate a Rebel, XP-E or XP-G? I see that the consistency of the optical grade silicone gel causes your "dome" to sag before it cures, but why not let gravity aid you? I do not know its viscosity or its values for surface tension, but maybe when held upside down, a dome might form a geometric shape in your favor (parabolic, spherical, elliptical, or catenary). If you are going for flatness, then why not temporarily fix it to the center flat spot of an old brushless PC cooling fan and let centripetal forces level off the top of the dome some? If the viscosity is high enough and you make the fan spin slow enough, you may get a very flat surface. As you spin it faster it may begin forming a parabolic dip in the center (like what happens with those experimental spinning mercury mirrors). You have a lot of control over the shape of this dome; that is awesome.
    I want the ring there because it performs a function. It holds the lens away from the die and makes sure that it is straight and level. Ideally I'd like it even higher than it is now. That will be in some future tests.
    I can create any shape that I want with this stuff. What I had was what I wanted to have. There is no need to spin it to get a flat surface as you can just use less of the encapsulant and surface tension will draw it tight if you have the right amount. That is not what I am after however.

    Quote Originally Posted by Gryloc View Post
    If that acrylic lens is the ultimate solution, then why not take an old Cree XR-E metal ring (or a spacer with the same height) and fix it above a Rebel, XP-E, or even XP-G then fix on the acrylic lens? Maybe a modded XP-G would produce a projected beam (in the Deft) of the same size as an un-modded XR-E from your existing setup (I am being hopeful here).
    The reason I am not even considering any of those LEDs is because they have neither the surface brightness nor the ability to over-drive that the XR-E does. Keep in mind I am always searching for a way to improve throw and this is the fundamental starting point for that.

    Quote Originally Posted by Gryloc View Post
    I am just asking that you try different setups with other emitters. We all bow to you since you have the optical grade silicone gel and experience. I like the XR-E, but have always been doubtful to the metal ring from the optical standpoint (I understand the mechanical purposes). If you can make a new dome over the tiny Rebel, XP-E, and XP-G, you might be able to shape the dome to do the same thing that the glass dome on the XR-E did, or you may be able to shrink down the apparent die size (flatten the dome) without sacrificing the total lumen output.
    I may try a different emitter some time in the future but for now I am going to stick with the XR-E.

    Quote Originally Posted by Gryloc View Post
    I always found the tint shift interesting. I also worry that the tint shift, while being pleasant to the eyes, may be bad for efficiency or overall longevity. It seems like a major change happens when the tint shift occurs, and it could be a bad change. Does it mean that more blue light is internally reflected back to the phosphor coating to produce reds
    (due to the change in index of refraction), or does it maybe affect how heat is removed from the top of the light which affects the efficiency of the phosphors?
    I highly doubt there are any ill side effects from the tint shift. I am not losing much in total output at all so there cannot be any real effect of heating up the die or phosphor. Any extra heat at the die level created by my encapsulation method would at worst be like dropping a bin in LED efficiency. I don't see Q5s failing because they are less efficient and create more heat than R2s so I'm not worried. It is strange that it shifted more red as whenever I have removed domes from XR-Es in the past(and not re-encapsulated) they turn a piss yellow/green. This is a nice change. It remains to be seen if this happens consistently though. I am sufficiently amazed though as it nows appears as if it is a proper neutral white color. Maybe in 3A territory.
    Quote Originally Posted by Gryloc View Post
    You could theoretically can cut rebel emitters down (the ceramic substrate) without affecting the etched traces to position the four dies tightly together so they almost touch (electrically, they could touch if you plan on wiring the dies in parallel). Just re-encapsulate them (or not if you cut cleanly) and this could equate into a quad TFFC die emitter. Its not a practical mod (with the MC-E, P7, and SST-50 out there), but I dream that it could be done.

    Cheers,
    -Tony
    That reminds me of another idea I had and still want to try out. The rebels would be ideal for it as well. My idea is to take 5 dies and position them so as to form a box. One would be flat as a normal LED. The other 4 are raised up to form the sides of the box with the top open for light to escape. The idea is that the four LEDs will help add some surface brightness to the base one which is the one the lens would be primarily focused on. You should be able to use an efficient cool white LED and have the resulting tint output to be warmer than it would otherwise. The increase in brightness would be minimal I'm sure but I am looking for any way to get ahead. It is just an idea I have had in my head and I have not had a chance to test it out as yet.

  19. #19
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    Default Re: Experiments in LED encapsulation

    Excellent work Saabluster.

    Do you think the phosphor being exposed to the air has changed the tint?
    In your 2nd picture the color of the top left is slightly darker.

    It's a wonder your DEFT customers aren't all over this thread looking for an upgrade! :-)

    Cheers
    Dom
    Last edited by dom; 11-03-2009 at 01:49 AM.

  20. #20

    Default Re: Experiments in LED encapsulation

    Quote Originally Posted by dom View Post
    Excellent work Saabluster.

    Do you think the phosphor being exposed to the air has changed the tint?
    In your 2nd picture the color of the top left is slightly darker.

    It's a wonder your DEFT customers aren't all over this thread looking for an upgrade! :-)

    Cheers
    Dom
    Even if you remove the silicone gel from off the top of the phosphor the phosphor itself is not coming in contact with air. The phosphor is suspended in a silicone elastomer that acts as a binder.

    You may notice that relatively few people come down here to the LED section. It is a place for LED geeks of which group I claim to be a part. Few people here truly understand the magnitude of what's been accomplished here but I'm fine with that. Thanks for noticing.

  21. #21
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    Default Re: Experiments in LED encapsulation

    Just a bit curious, what's the spatial distribution now like? If it's not too much hassle I wouldn't mind seeing some pics of how it's distributed, even if it's just holding up a piece of paper on the axis of the LED or some similar method.
    Finning does help dissipate heat. This is why the fins are removed before cooking fish. Otherwise it will throw off the heat and not reach the proper cooking temperature. --Duglite

  22. #22
    Thread Killer Illum's Avatar
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    Default Re: Experiments in LED encapsulation

    I'm inclined to ask, why the encapsulation of the dome only and not the entire LED?
    I'd figure that if this is a mean to provide protection for the LED the weak link still exists from lateral shear, where impact or trauma from an angle may still take out the LED from the PCB substrate [NOT the star] below.

    I like the dome encapsulation though, definitely one of those things to have for fixed lighting projects, especially if theres some way to create an increase in die projection
    Last edited by Illum; 11-03-2009 at 08:18 AM.

  23. #23

    Default Re: Experiments in LED encapsulation

    Quote Originally Posted by Th232 View Post
    Just a bit curious, what's the spatial distribution now like? If it's not too much hassle I wouldn't mind seeing some pics of how it's distributed, even if it's just holding up a piece of paper on the axis of the LED or some similar method.
    I'll try to get some pictures up for you as soon as I can.

    Quote Originally Posted by Illum View Post
    I'm inclined to ask, why the encapsulation of the dome only and not the entire LED?
    I'd figure that if this is a mean to provide protection for the LED the weak link still exists from lateral shear, where impact or trauma from an angle may still take out the LED from the PCB substrate [NOT the star] below.

    I like the dome encapsulation though, definitely one of those things to have for fixed lighting projects, especially if theres some way to create an increase in die projection
    Because the dome is where the light comes out. Not really sure what you are getting at there.

    This system is no different than the one Cree uses and has the same failure modes. It should should survive high G event just fine. It would be slightly more prone to having the dome pop off if bumped as the lens no longer has the ridge of the ring to help prevent lateral motion. My point in doing this experiment was not to create a more robust package but to create better package optics for our specific application. I think I have done that.

  24. #24
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    Default Re: Experiments in LED encapsulation

    Way to go! I was actually thinking of doing something like this to my Bridgelux since it is such a massive led as far as emitter area. The bridgelux is cheap, easily driven, and has no problem putting out over 3,000 lumens....but all that light is a real trouble to put into a beam without an aspheric condenser right on the dies. Again, great job and congrats.
    Still Tinkering

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    Default Re: Experiments in LED encapsulation

    Quote Originally Posted by saabluster View Post
    This was just a proof of concept.
    And a darn good one

    I'd love to get my hands on a few if you crank some out for sale.

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    Flashaholic* bshanahan14rulz's Avatar
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    Default Re: Experiments in LED encapsulation

    do you think regular norland gel (or whatever it is kids call it these days) that you can buy in the MP will work? I might be getting some for some trits and figure as long as I have it, I could use it to thinly protect my xr-e.

    I'm hoping for crazy throw, even in an OP reflector, since preliminary tests (Me holding emitter on reflector with low current) seemed to show that I could still achieve focus *eventually*

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    Default Re: Experiments in LED encapsulation

    Quote Originally Posted by Inliner View Post
    And a darn good one

    I'd love to get my hands on a few if you crank some out for sale.
    Thanks. We will see. I still have a bit of testing to do.

    Quote Originally Posted by bshanahan14rulz View Post
    do you think regular norland gel (or whatever it is kids call it these days) that you can buy in the MP will work? I might be getting some for some trits and figure as long as I have it, I could use it to thinly protect my xr-e.

    I'm hoping for crazy throw, even in an OP reflector, since preliminary tests (Me holding emitter on reflector with low current) seemed to show that I could still achieve focus *eventually*
    I believe the Norland people use for trits is an epoxy and most definitely will not work.

  28. #28
    Flashaholic* bshanahan14rulz's Avatar
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    Default Re: Experiments in LED encapsulation

    aww, k. Well, there will still be a glass window between the outside world and my LED.

    I've always thought that even though it is said to reduce output, it would be worth it to remove the lens just for the higher amount of light per area of light emission (even if overall light emission is lower)

    Anyways, I'm gonna sit back and watch the show

  29. #29

    Default Re: Experiments in LED encapsulation

    excellent work once again...your dedication to every foot of throw is unbelievable...That must be what makes your lights so perfect.
    Enlightened from birth

  30. #30
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    Default Re: Experiments in LED encapsulation

    Quote Originally Posted by saabluster View Post
    That reminds me of another idea I had and still want to try out. The rebels would be ideal for it as well. My idea is to take 5 dies and position them so as to form a box. One would be flat as a normal LED. The other 4 are raised up to form the sides of the box with the top open for light to escape. The idea is that the four LEDs will help add some surface brightness to the base one which is the one the lens would be primarily focused on. You should be able to use an efficient cool white LED and have the resulting tint output to be warmer than it would otherwise. The increase in brightness would be minimal I'm sure but I am looking for any way to get ahead. It is just an idea I have had in my head and I have not had a chance to test it out as yet.
    I've been following this thread a bit and as I read the above, an idea popped into my head. You have probably though of it before but here it is.

    The yellow parts would be the die of the LED. The blue stuff can be whatever is used to connect the pieces of metal in grey. There will be 5 pieces of metal for the heatsink. The base one would have the LED on a pedestal with the substrate cut away as much as possible. The electricity would be conducted through the bottom of the LED. The other dies would have a LED at the top left corner of a rectangular piece of Al or Cu with the substrates cut aways as much as possible and electricity also conducted through the bottom. Then the rectangle pieces with an LED at a corner will be fit around the base piece with the LED on a pedestal. Does that make sense?

    I don't know how the bottom contacts/thing would work though.

    Great job with the experiment!

    Would this work?

    A highly polished reflector (maybe of Al) with a silicon encapsulate LED or one you modified yourself pointed towards the reflector (like the pelican recoil system), filled up to the brim with the same silicon encapsulate used for the LED to reduce the apparent die size to the actual die and also prevent oxidation of the reflector which should result in more throw. The wires and heatsink bars to the LED will block some light though. The LED can sit at the bottom of the reflector like normal, but that increases the rays of light not hitting the escape surfaces at perpendicular angles. Maybe a well designed lens for use in the silicon encapsulate can be suspended at the right place to redirect the non perpendicular light rays to perpendicular. Am I making any sense?

    Either way, looking forward to more results!
    Last edited by Gunner12; 11-03-2009 at 12:45 PM.

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