If this is even remotely true, it should be easy enough to test. Without the dome of maybe RI ~1.5, the output should drop in half, which is hard to believe given the results here.
Also the RI = 3.7 is of the semi material itself (transparent to the emitted wavelengths), not phosphor layer.
The focus of the dome is evident enough from its shape and >1 RI, and comparison between CREE app note and COS curve as already noted.
Well, de-domed a XML headlamp ( ~38mm reflector), while it still goes I removed a fair bit of phosphor from two of the corners… the pictures can explain better then I can:
Before:
After:
Left to right: P60 XPG at 1A, OP reflector, XML at 800mA in 38mm SMO reflector and Trustfire X9 at 2.4A ( batteries needs recharging)
Smaller hotspot and marginally more intense, still good for all flood as the colour is even (if slightly blue) without the reflector.
I pressed the LED dome lightly against a hotplate for about 10 seconds before pushing it upwards with a knife blade…. I don’t think I let it get hot enough or perhaps I should have heated it from the underside? Going to replace the LED anyway now.
Don’t want too much from this little light. Other lights have a (much) larger reflector in this topic where has been measured 120-180-200kcd. So, it’s not fair to compare with them. With an original xm-l it can 45kcd maximum, and this increased to 85kcd, it’s not so bad.
Not so bad??? It’s an outstanding value from such a little light.
85kcd is really really good result for a single battery light. Not to mention the $15 pricetag (without emitter swap yet of course).
Anyone doing this on Small Sun T13? Nice big reflector there, standard T6 XM-L ready to peel, and with the resistor mod it should really give good result.
I plan to do T13, but mine has not arrived yet. And even if it did, I don't have a way to measure lux anyway to publish result.
Nice beamshot viffer750. Amazing the warm (er yellow) shift on these de-domed. Mine too. I est from 3C 5000K to 3500K (er yellow). IF I do another, I’ll start with a U2 1A and hope to end up at 5000K. Craig at Illumination Supply has some U2 1A on 16mm boards on sale for $6.50……
You're absolutely right, Viffer. That little A0 clone is so small I forget that the reflector isn't as big as it's output makes you think it is. That is an amazing difference!
They cost me >$15US each and include aluminum reflectors, glass lenses and an overall very good fit and finish considering the price.
Three of the five have quite cold tints so I decided one of those needed de-doming. I used the Dremel method this time: ground the LED dome down to <1mm and stuck the felt wheel in before finishing with a optics cloth.
So far it looks very promising: When at 2.5A (battery at 3.8V) it throws as well as a X9 at 2A (3.6V) however the hotspot is 1/2 the size…. just recharging the batteries to put them both on a even footing… photos to follow.
Had to a have another play around with the C8s…. and here is what i got:
The partial de-domed I mentioned in the post a few above is on the left and a complete de-dome on the right, both were the same tint before any mods.
To do this I used the method of running the LED until it got very hot (took pill out of C8 body and attached it to a battery, took all of 1 min to get hot enough) and then I just peeled it off… piece of cake and left a perfect finish.