Modding the Diode

I have bought several LED flashlight modifications, and I like them all, however a question cropped up into my mind.
I know that there are ways to make to make normal diodes emit to the sides by grinding the epoxy in a certain way. This is done to let the LED use the flashlights reflector.
My question is: what is the best method to make LED's emit sideways? Is there anyway somebody at home could make the mod? Is there any way to make 100% of the LED's light go sideways to reflect off the reflector? I would want this so that a very tight beam can be made from a flashlight. Thanks

There are Luxeon side emitters available if you were to be makeing a mod from scratch. I don't know if they follow the same bin codes as the low and high domes.

I have heard of this being done on T1 3/4 5mm white nichia type LED's. I believe the head is made concave by using a drill bit right down the center of it and stopping before you hit the die. The whole thing sounded quite "hit or miss" and never captured my interest enough to ty it..

this can't be done with luxeons.

the aren't totally epoxy (actually, isn't epoxy at all, some other material...), anyway, inside the clear "shell" there is some clear goo, dubbed "farkle" by our very own peter gransee.

furthermore, there is absolutely no way to emit 100% of light sideways. even the luxeon se's seem to do a not-all-that-great job...

A luxeon side emitter is what you want. There is an inverted cone on the top of them that reflects a considerable portion of the light directly out to the side. Some light is still sent forward, but only from the very middle anyway, so it won't make any difference unless you're TRYING to have a m*glight style beam /ubbthreads/images/graemlins/wink.gif

As Rothrandir mentioned you can't file the case on a Luxeon, they are a glass bubble filled with a silicone "goo" for better heat transmission i think, or perhaps thermal expansion issues.

i've seen a couple of folks now do the mod that Slick mentions. Basically you're creating teh inverse cone into a regular LED by drilling into it. As brilliant as this is I don't have the tools necessary to do it properly. If you don't center the cone exactly right the beam is going to be horrible lopsided. Also, it would loose a lot of light if the drill hole cone isn't polished nicely which I also have no idea how to do.

You can flatten out a regular 5mm or 3mm LED to create a much wider beam out of it making it somewhat focusable in a deep reflector. But this is really not that efficient either unless you polish the top nicely.

If you can use a luxeon Side Emitter thats the way to go.

The 'non epoxy' case on the Luxeon is for "light output maintenance" or so their write up of that title says. Seems high light levels eventually darkens epoxy, so they avoid it.

Heat is pulled out the stub I assume?

Doug Owen

luxeons are designed for the heat to go out the slug in the ls's butt. however, a little also goes out the top and the leads.

the "goo" or "farkle" isn't only for better thermal transmission, it also acts as a optical bonding agent, makint the light travel from the die and through the clear "case" more effiecently than plain air.

As far as grinding the domes on LEDs, I think that would be a real trick and I have to say I am as sceptical with the outcomes as Slick. I have pulled a couple of low domes apart and set an acrylic ball right on the farkle locking it behind the ball which has worked well (this was not planned it just worked out that way after the domes came loose and the LEDs turned green).
I was just thinking a guy might be able to take a small stainless steal ball bearing that has been buffed up real shiny and set it into the concaved area of an se to get a total side emitter. Sorry I there I go thinking again. /ubbthreads/images/graemlins/yellowlaugh.gif If a guy got the right size ball bearing and did this with a high or low dome recessed in the dome he might be able to do the same thing as well. /ubbthreads/images/graemlins/twak.gif Okay Okay I'll stop it now!

If you have a lathe you can do it to T1-1/2 leds. Twist the leads together to reduce the chance of frying the led with static charge. Chuck the led with the leads sticking out and trim off the base flange. Reverse the led and chuck it to run as true as you can. Use a 90deg (or 88deg) CNC spotting drill to cut in past the curved end. Polish with a leather point and plexiglas rouge. Should only take a couple of tries on cheap red leds to get the hang of it.

A CNC spotting drill costs as much as a LS so if you want to do only a couple it has to be because you just want to see if you can do it.