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View Full Version : OT: can you cut the top off an LED?



Kyle
2006-06-02, 10:37
LEDs look like they're just encased in solid acrylic or something. Can you cut the dome top off as long as you don't get into the wiring part? I want to embed some LEDs for a backlighting project, and I need them to be a little smaller.

Mark Lanctot
2006-06-02, 10:55
Yes, you can cut, shape, sand or file an LED. I've done this several times in model railroading projects.

I believe the plastic material is actually epoxy.

As you note, don't cut into the element or the very fine wires leading to it and it will work fine.

Edit: take a look at this photo of a white LED. You can cut all of the transparent material. Do not cut any of the solid structures. There will be very fine wires leading from the cathode and anode to the element. Don't cut anywhere near here - they are so fine that stress on the nearby material may break them. This white LED pictured has a fluorescent chip in front of this element so you can't see the wires, but they're there and just as fragile.

http://www.btinternet.com/~jg/pics/Led.jpg

pfarrell
2006-06-02, 10:57
Kyle wrote:
> LEDs look like they're just encased in solid acrylic or something. Can
> you cut the dome top off as long as you don't get into the wiring part?
> I want to embed some LEDs for a backlighting project, and I need them
> to be a little smaller.

I would not expect it to work after you do that.

Just go to Digikey or Mouser and
find some smaller LEDs. They have tons them
down to surface mount units that are nearly too small
to see.

depending on your skills and microscope, 0603 is about
as small as most folks can go.



--
Pat
http://www.pfarrell.com/music/slimserver/slimsoftware.html

rudholm
2006-06-02, 17:21
Though you can probably get away with truncating the envelope, bear in mind that the envelope material is part of the LED's thermal management and if you remove some of it, you'll increase the operating temperature of the junction, which will either do nothing, burn it out, or simply shorten its lifespan.

The development of a suitable envelope material with the needed thermal an optical characteristics was one of the hurdles in manufacturing high-power LEDs that could penetrate the lighting market. It wasn't just about the junction chemistry.

But yeah, I'd say it's worth a try at least. As others have said, just be sure to avoid the metal bits.