someone save a SBT-70 for me! lol been wanting to build a thrower with one for a while
To the OP; LinusHofmann,
I hope you don’t mind the side-discussions going on in here. I have undoubtedly introduced other topics being discussed, which I initially found to be relative to projects like this, but more so when tweaking a design for “optimums” are being considered. So, I don’t mean to dump info here, which may be useful in its own thread. What do you think? If at any time you’d rather I do that, I can start a thread on the various principles of LED emission as to not discuss such things, next to your project. Anyone who feels that would be better suited discussion on these topics, please make mention or PM me.
Anyways.
What Cajampa just mentioned is a very interesting configuration which I myself have pondered.
So one thing which can be found in experiment is that in fact yes, if the dome can be sliced-off effectively leaving a thin gel layer, a reduced-die-size image will thus be presented to the focusing optic, as is the case in a complete de-dome scenario. The reduced-sized image is beneficial in one clear way in either type of de-dome method, lux is boosted as the natural die size is not virtually expanded. Many consider the boosted intensity-per-area the best benefit from a de-dome; a complete de-dome that is most often. But the second thing we have come to expect, is the loss of total lumens after a de-dome. This negative seems to be traded equally by most minds for the additional gain of a lower kelvin tint, which some view as a benefit to higher final CRI. But the final CRI values are not often known as well as they are when the LED has a specified, or specific manufacturer recorded bin. That bin value thus becomes lost. We don’t really know the final bin, and if it is productive towards actual CRI. My guess like many would be that it is beneficial to CRI even if now unknown, as we generally see warmer tints represent higher CRI values. Unfortunately, little data actually confirms the final benefit beyond our eye-sight. So if we achieve what is considered a good color tint after a de-dome, and we further change that tint-shift using a reflective aperture, the next question would be, now what is the tint bin? Have we gone too far? And etc. It might be assumed that the gel used by the manufacturers over the LED surface is their optimum choice for boosting lumens, and if it is a perfected technique they use to in fact boost lumens, should we remove all of its benefits when we merely seek the smaller die image only? These are questions which could only be solved by an integrating sphere. If we can attain higher lumens, and a smaller die image by slicing the dome, we have just increased the potential light density attainable which previously is not being met in a complete “solution de-dome” method. If we can then lower its kelvin temperature a desirable amount, while still increasing surface intensity using a reflective aperture, might we be able to yield the most energy-dense configuration attainable for an LED?
I think these are good questions to ask, because while many thought they found an “easier” de-dome method, it seems true they did not consider all variables with the solution or “dissolve” method. It seems like this could have easily been overlooked by the hundreds if not thousands of people now currently using this method. Is it really the proper way to gain maximum effectiveness and benefit?
Someone should definitely want to consider what I have stumbled across here, and tests could be performed to verify, or prove a null-concept, by one with access to an integrating sphere. Of course the multitude of configurations would play into effects. How clean is the slice? Is a reflective aperture then used? Each variable has an outcome to the method’s final benefit. But these are clear options right there all along, and no one has really documented any of this. We go on a wing-and-a-prayer that it is just done the way it is done properly, without ever really knowing. Substantial lumens are lost in a complete de-dome. That seems to me like there could be a substantial benefit to keeping those lumens there, while achieving the original goal of a reduced image size. Intensity should seemingly only go UP^. 
The second problem, to me, is the reflective aperture. Some surfaces are not suitable mirrors, regardless to how well you polish them. Certain metals will still collect photons of certain wavelengths, even though they may appear shiny and reflective of all colors to the eye, some light is still lost/scattered in the reflection. This would bring the mirror process of the aperture into question. A mirror coating with proper reflective index would be used, on top of a properly machined hemisphere surface. A guy from a club I belong to claims that he can machine hemispheres to very-high tolerances such as required in optics. Unfortunately he won’t do this for free or I would have many by now. He has a very high-end CNC machine at his shop, which I do not. What he has told me is that the apertures would come out with a near polish—just due to the machining accuracy. So if some of these could be made, then coated by a mirroring process that is efficient with LED light colors directly (unlike uncoated metals, such as stainless steel), a “super-combination” could potentially exist, within arms reach. Don’t mean to sound too overwhelmingly certain this would be the solution to maximum attainable LED surface-intensity, but the logic put behind thinking about it does make sense, all things considered. We aren’t currently using coated apertures, nor precision ones, in an optical sort of context. While going about such a design through a professional optics route would undoubtedly cost some $$$, going about it the “custom way” via a machine shop with a good CNC, and then coating, is what would put such a design within arms reach when I say it.
Just things to consider. Maybe more would be interested in pursuing a group project, or a design intended to be mounted on a specific light pill. One design applied to the optimum host, in other words.
I personally don’t see a problem with OT discussions in any thread, that the OP hasn’t explicitly asked for it to be no OT, BUT i am a serial OT poster myself here at BLF 
And i of course will follow whatever the OP Linus wants
The very lenient attitude to let discussions weave in & out of various thread here at BLF, i feel is a big reason for the collective high level of intuition that constantly pushes the boundary’s of what is possible here.
And back to the slightly OT, output optimization discussion thats always my favorite in all its forms
Interesting if such a high quality reflective aperture could be produced for a group buy, i would say of the big lens lights the UF-1405/1504 looks to be the one gathering the most interest here at BLF, and i would think most of us who want that kind of light is after the potential high kcd it can produce. An RA as short for an reflective aperture designed to fit that platform i think has the biggest chance to gather enough interest for a GB.
Maybe the same places that can do AR coating on uncoated lenses can do various mirror finishes on metals also.
The coldest XP-G2 in the highest flux bin available, i believe is the S3 1C cutter sells them also.
This should be the best starting point for maximum lux when combined with light recycling, like an reflective aperture or an sliced dome or even possible an uncoated small lens.
To bad there is always the led lottery, i read that some are buying several & tests all of them & chose the one with the lowest Vf, to get higher on the top flux bin variation scale.
I wonder if a slice left will up the lumens more than an tiny uncoated lens will, but it is very easy to damage the dedomed emitter so i don’t really believe this to be a usable option. If not such a combination would show to be worth the extra risk by raising the performance to make it worth it, much like the normal dedome is.
By all means, discuss whatever. It’s all interesting stuff and I don’t have any progress to post on the light at the moment so carry on.
I don’t have much to add on the dome slice approach but I’ve done it in the past and foudn it fairly fiddly. Crucial is polishing the surface and I never really got a good result so I was rather pleased when someone came up with the gasoline/solvent dedome method.
CerealKiller illustrates his method for dedoming an MT-G2 here.
Is it really crucial to polish the sliced dome? when i gas dedome i always slice first with a new Feather Hi-Stainless Platinum Double Edge Razor Blade & the slice look pretty clear after i sliced it, it is the sharpest razor blade i have found yet & the same blades i use in my safety razor.
To my knowledge the “dome” is one material, dome “filler” is a second material, and lastly the glue would be the third material. Typical gasoline de-dome methods actually only remove the bottom glue layer around the ceramic surface; they don’t actually dissolve the filler or dome, but both are softened somewhat by the polymer saturation of the fuel it will absorb. (A two-phase de-dome is capable of dissolving the glue followed by the entire visible dome filler into a liquid.) Anyways, polishing a gel seems pretty awkward sounding if you ask me. lol. But indeed, it might be practical to “clean up” a non-flat dome slice if it happens, since any edge or surface anomaly will carry light forward and out at an odd angle like a bent fiber-optic cable.
Take a gift card or old credit card, drill a hole, ream hole snug on the dome base for the taper, lay it on, then slide razor across dome. Bond wires sit under a mm height, so that much plastic+blade will clear them with a thin layer left. Do not disturb the dome base with excess force! You can create a separation bubble at the die surface, under the gel. It won’t be seen until viewed under magnification, so, light pressure when slicing.
Whenever you do this, set your camera to manual, with lowest ISO you can get by with, and auto-white=OFF. Focus the die image on a piece of cardboard with some grid shown or drawn before and after slice. Be sure to document your tint results, cameras help tremendously (especially if you have an option to save data in “RAW” image format for Adobe software, like Nikon’s do). Some people use white backer boards which is OK, but I find flat-black foam-center craft cardboard stock at WM to be very good for rendering the colors from an LED, for photo-program analysis.
The lens coating company has my sample arriving Thursday through UPS. I am going to speak to them about mirror processes later on. They should deal with this sort of thing I would believe.
Oh, LINUSHOFMANN, you can start this test for us with an XHP-70 PLEASE! That should be an easy one. Hehe
I did not seen this thread before. Well done guys :)
I tried shaving and polishing dome with dremmel but not as good as gasoline de doming.
Hi luminarium iaculator good to see you here
Was there any noticeable tint shift when you sliced the dome & used it?
And did you test one of the things we are discussing here, the sliced dome to retain an colder more energetic source for reflective aperture light recycling? I think i remember you experimenting with collars before.
@MEM, i don’t have an host yet so it will take some time before i have an reason to test but, i realized some days ago that i have an colorimeter, the X-Rite ColorMunki Display, that i use for calibrating my monitor/HDTV with dispcalGUI, that is a GUI for Argyll CMS. This should when i figure out what program to use & how, be able to accurately test LED’s for color output & quality EDIT or maybe not.
EDIT
I removed some wrong here information, sorry.
Argyll CMS is command prompt only, if i want to use it for anything other than display calibration and a little daunting to get a handle on.
You could use part of an old projection tv screen. It’s a flat fresnel lens. Cut out a square to set the meter on, with LED aiming at the screen section. I have the screens in my shop if it was actually useful. But i know what you speak of. I had one that hung by the cord over the monitor, triangle shape, and then basically “looked” at different screen sections where the software would place boxes. But a quality camera with images fed into Photoshop should be another crude method to see amounts of colors. A method could be devised to look at the LED light portion only. Then baseline made from starting bin. The harder part to achieve is intensity which is for a lux meter anyway, but color spectrum should be fairly straightforward to plot.
The ColorMunki Display have 2 different modes, one is the Ambient Light Meter mode.
And the spot mode, the normal screen calibration mode when you hang it on the screen you want calibrated.
I don’t have access to any fancy cameras at all, the best i have is an old point & shot camera with very little set up capability. i have tried to take pictures of beamshots with it and utterly failed. So the colorimeter is my best chance.
Your triangular colorimeter is probably a version Datacolour Spyder & those are supported by argyll cms.
EDIT
Hmm i have tested with argyll cms spotread, and read up on other tools, and it looks like most only work best with a proper spetrocolorimeter :(, i had planned to get one to profile my colorimeter sooner or later so i guess this moves it up on the wishlist.
So far i have been able to take lux & colour temp measurement & i get cordinates on the CIE chart.
I got a bit blurred projection because I could not get ultra clear polishing, and maybe small tint shift if I remember right... I did this year ago, and than I toss that in a gass for clear dedome. It won't give better results under aspheric lens for sure.
I am not really sure if polished silicone (XP-G2) can act as more energetic source than clear dome and if it can there will be less output from emitter than with clear de-dome anyway. So if less light comes to wavien there will also be less intense reflection on polished dome.
I am pretty sure that Saabluster(OMG Lumens Deft X) tried that and he decided to leave clear dome on DEFT X.
We should make emitter surface more reflective like thin film of transparent mirror particles spray 
Edit 1000 000 kcd DEFT X here:
Interesting, so you say that the Deft X is with the XP-G2 dome still on?
What does it do with a dedomed XP-G2 then?
And how large is the aspheric in it?, is there only the xp-g2, collar, and a big fat aspheric in the deft x.
And you forgot to remove the k in kcd
I don’t think so, certainly in that picture it looks like the emitter is dedomed.
I suspect he means “full dedome”, eg. the solvent/gasoline when he says “clear dome”. Is that right luminarium iaculator?
Out of curiosity, what diameter is the aspheric lens used in the deft-x?
I agree that it look like it is dedomed in the picture.
As an extension of the thin dome sliver approach and how it affects the balance between apparent die size and emission characteristics of the light.
I wonder what effect a full dedome followed by a layer of led seal has on the equation.
Essentially you are adding back on a very thin rather flat “dome”, so I would expect that to have some effect. Purely in terms of altering the phosphor layer interface from Phosphor/Air back to Phosphor/Substance.
I realize the refractive index of the led seal would be different to the silicone dome. However it should make a perfect/gapless interface with the die phosphor and by my understanding that should have a somewhat similar effect in terms of emission.
I’ve never applied the sealer myself but maybe someone here could share their experiences with it, does it affect the tint after a dedome at all? Is the Deft-X led sealed?
Your first statement is correct, but knocks the should out of your second statement. If you do not know their reflective indexes are similar, there is no should. Hehe. I have a couple LEDs with seal on them, I do not use it personally. Problem is I don’t know what tint they started at.
Man, Wavien really can’t get their process done right. An optical aperture edge should not look like that, IMO. But hey it worked. Looks like a 20-25mm aperture hole.
I too am curious about the lens. Diameter, and BFL. Or, the clear aperture size that is exposed, even (between bezel edges). The reflective aperture creates a system which is F# limited. What do I mean by that? No matter what lens you use, it is limited by the “F#” created by the reflective aperture. You can change that by opening the hole. As you open the hole, less spill light is reflected back upon the LED, changing the surface intensity. A point exists where optimum reflection exists with any set of a few proper lenses. Of course, closing the hole down to a pinpoint will recycle a lot of light back, but that makes it a high-F#, becoming undesirable/unusable for aspheric lenses with lower F#s.
My wild guess though, is that the lens is around 60mm clear aperture size.
Hi!
I love the aspherical beams ! I have a lot of mod with them, the better is a dedomed xpg2 at 5.5A, wavien collar and 78mm aspheric lens, I am above 1300 kcds the secret is in the focus of the collar, was many hours working on it :_( as they are very very fine adjustments (tenths of millimeters) to achieve the maximum performance…
Yes when I said clean dome(which is wrong expression) I thought on full dedome version, nice and clean with solvent/gass method. We all know that dedomed emitter out throws domed one so no freaking chance he could done that.
Deft X is de-domed like in picture. Lens diameter is 70mm I think.
Probably he did not want to try bigger ones because XP-G2 would have really small die projection...
Do you have this light or you sold it? Please show us this beast because you break record in 78mm size. 1300kcd!
+1
1300kcd is impressive, please do a built thread.