how does a dedomed XM-L functionally relate to a XP-G, idem for dedomed XP-G -> XP-E

[djozz]

Did a small search, but did not yet find the answers:

If you dedome a XML (T6), will the virtual die size in a flashlight be similar to that of an intact XP-G (R5)? And will the efficiency be similar to a intact XP-G (R5) ?

the other question:

If you dedome a XP-G (R5), will the virtual die size in a flashlight be similar to that of an intact XP-E (R2)? And will the efficiency be similar to a intact XP-E (R2) ?

Please don't do the research for me, I should do that myself, but please answer these questions if you happen to know the answers (because you may have asked the same question yourself sometime?)

[dthrckt]

did you see Dr. Jones thread on luminance, de-doming, throw, etc?

I’d have to re-read that thread to answer on “virtual” die size, and I think what you mean really mean is luminance? and my vague recollection is that de-doming doesn’t change that (die size is what it is, only the angle of the light that gets emitted changes)

and, as far as efficiency - that is obviously decreased, and my guess, based on the overall output I’ve seen in a few posts (pre and post de-doming), the difference (loss) is greater than the efficiency gain from xml/xpg/xpe to xml2/xpg2/xpe2

but, i’m no expert, and could be entirely wrong!

[djozz]

@dthrckt

did you see Dr. Jones thread on luminance, de-doming, throw, etc? I’d have to re-read that thread to answer on “virtual” die size, and I think what you mean really mean is luminance? and my vague recollection is that de-doming doesn’t change that (die size is what it is, only the angle of the light that gets emitted changes) and, as far as efficiency - that is obviously decreased, and my guess, based on the overall output I’ve seen in a few posts (pre and post de-doming), the difference (loss) is greater than the efficiency gain from xml/xpg/xpe to xml2/xpg2/xpe2 but, i’m no expert, and could be entirely wrong!

I did see Dr. Jones' article, it gives a good insight in what is happening upon dedoming, but it does not provide the empirical numbers that answer my practical questions (one of them is: am I going to use a dedomed XP-G2-3C in a light or will I wait untill a XP-E2-3C becomes available through accessible distributors).

[Slim_Pickens]

@djozz

@dthrckt

did you see Dr. Jones thread on luminance, de-doming, throw, etc? I’d have to re-read that thread to answer on “virtual” die size, and I think what you mean really mean is luminance? and my vague recollection is that de-doming doesn’t change that (die size is what it is, only the angle of the light that gets emitted changes) and, as far as efficiency - that is obviously decreased, and my guess, based on the overall output I’ve seen in a few posts (pre and post de-doming), the difference (loss) is greater than the efficiency gain from xml/xpg/xpe to xml2/xpg2/xpe2 but, i’m no expert, and could be entirely wrong!

I did see Dr. Jones’ article, it gives a good insight in what is happening upon dedoming, but it does not provide the empirical numbers that answer my practical questions (one of them is: am I going to use a dedomed XP-G2-3C in a light or will I wait untill a XP-E2-3C becomes available through accessible distributors).

The tint of an emitter becomes warmer after being dedomed. E.g., XP-G2 3C will no longer be ‘3C’. If tint is an imperative (which it seems to be) you may want to wait for a 5000k XP-E2.

[dthrckt]

I think the only way you’ll get a quantitative answer, is if you test it, and I for one will be very interested in the results if you do

[djozz]

@dthrckt

I think the only way you’ll get a quantitative answer, is if you test it, and I for one will be very interested in the results if you do

sounds like a small project :-)

[dthrckt]

yes, but beyond the numbers, how practical/suitable you find the end result is likely subjective, and dependent on the reflector/lens combination, and your uses…so if you do it, at least you’ll be confident in your final setup

i for one would always wonder if I didn’t, which is why I have as many projects in the works as I have finished lights lol

[djozz]

@dthrckt

yes, but beyond the numbers, how practical/suitable you find the end result is likely subjective, and dependent on the reflector/lens combination, and your uses…so if you do it, at least you’ll be confident in your final setup i for one would always wonder if I didn’t, which is why I have as many projects in the works as I have finished lights lol

That sounds familiar .

Now, for that small project, an answer to the first part of the question (about the 'virtual' die-sizes):

I put some leds together for fun, even roughly dedomed (and destroyed ) an old XM-L for it.

The answer is yes, the die size of a dedomed XM-L and a XP-G that is 'seen' by a smooth reflector or aspheric looks indeed similar (ddXM-L just a bit larger), and the die size of a dedomed XP-G and a XP-E that is 'seen' by a smooth reflector or aspheric looks also similar (this time the ddXP-G is a bit smaller). So in both cases you can expect similiar hotspot sizes.

The second part of my question (about efficiency loss of dedoming) I can not answer myself, have to look that up sometime.

Just because I was making pictures of leds I made a picture of some leds taken from the side in a row so that you can see what the shape of the different domes are. There are some clear variations as you can see, e.g note that the XP-G2 dome is significantly larger than XP-G :

From left to right: Nichia219 XP-G2 XP-G XM-L XM-L2 XP-E

[Slim_Pickens]

Those are some cool shots and interesting observations.

[dthrckt]

if you let that de-domed xr-e sit in acetone for awhile, then give it a few squirts, it will clean off the silicone so that it can be used

i use one of these with a more narrow tip for squirting Vape Store Online | e-cigarettes, e-liquids, vape kits & pens | myvaporstore.com

[Tecmo]

@djozz

The answer is yes, the die size of a dedomed XM-L and a XP-G that is ‘seen’ by a smooth reflector or aspheric looks indeed similar (ddXM-L just a bit larger), and the die size of a dedomed XP-G and a XP-E that is ‘seen’ by a smooth reflector or aspheric looks also similar (this time the ddXP-G is a bit smaller). So in both cases you can expect similiar hotspot sizes.

Which is why xml dd throws better than xpg. Same apparent size with more lumens. Same with the dd xpg2, same die more lumens.

[dthrckt]

dedomed = less lumens, but higher luminance

[djozz]

@Slim Pickens

The tint of an emitter becomes warmer after being dedomed. E.g., XP-G2 3C will no longer be ‘3C’. If tint is an imperative (which it seems to be) you may want to wait for a 5000k XP-E2.

Yes, of course, you are right. I may have to use a dedomed 2A-tint xpg2 to get the 3C-tint. I hope that Illumination Supply will have the xpe2 in different tints soon, Cutter is too expensive for just a few leds (and just has a 5700K xpe2), and so are Mouser and Digikey.