semi OT- removing plastic lens from LED

Can't you buy a flat-end LED?

One problem with the lens-end ones is that the chip placement isn't usually very good, so the major light axis can shoot all over the place. Data sheets generally lie about that, showing beautiful on-axis intensity patterns. Flat-end LEDs radiate pretty uniformly.

This may be folklore.

I often work with high-temperature stuff, and the wisdom is that you can't use conventional LEDs at 180C because the lenses melt. I've never needed to and haven't tried, but just maybe they'll soften sufficiently to aid removal.

Some of the small SM ones seem to have Silicone lenses which it might be possible to remove carefully under a microscope. Silicone oil will soften Silicone rubber a little.

Cheers

Try hot (~85'C) red fuming nitric acid. You said a chemical would be nice, but that is not a nice chemical.

Johne Wayne would have put the LED on a fence post, step back 30ft, draw and pull the trigger.

When looking at the 5mm through-hole LEDs I have here they are all fully encapsulated, "immersed in plastic". And as John said, with the placement precision all over the map. Not sure what you are trying to design but you may be better off buying bare die. I don't know them, just as an example:

standard' 5mm through hole LED? I've used a file to get ~90% down to the e lement, but I'm afradi if I go further I'll wreck it.

hopefully *not* methylene chloride.

Well, I'm using this red led as a light sensor. I was taking some data on response vs light intensity. (using a yellow led as a light source) And t hen I tried a green led (as a source) And though there were more photons I got a lot smaller signal. WTF I thought to myself, well maybe the red pal stice lens is absorbing all the green light. So I filed it down and increa sed the signal by a factor of 5 or so... Now if I could just get more of it off...

When hitting this with a file I'm afraid I'll 'take out' the little bonding wire and that will be the end of it.

George H.

Hmm OK maybe I can 'dig' around a bit with a soldering iron tip. Thanks,

george H.

"Arghhhh... Run Away!!" I've never heard of red fuming nitric acid but it sound like methyelene chloride would be safer.

George H.

You can get red LEDs in untinted packages.

Cheers

Phil Hobbs

"I'd never shoot an LED in the back."

I guess I'm just going to have to settle for a bit of filing... I tried digging a bit out with the soldering iron and broke one.

George H.

Could you not simply buy a red-emitter LED with a water-clear plastic lens? They're common and not at all expensive. Seems like a lot less trouble than trying to grind down or dissolve red plastic (safely).

Run, don't walk, to your nearest library that keeps old books, and get a copy of "Some Birds Don't Fly" for a fuller appreciation of RFNA (and quite a few chuckles.)

Last time I went to Home Depot I didn't see any consumer grade methylene chloride.. has it been outlawed or something?

Red plastic does absorb green light!

Umm, why not use a silicon photodiode? You'd get approximately

Why not a flat-lens surface-mount LED? Or a proper photodiode?

Yup. Or better yet, buy them with flat lenses:

Even whole tail light assemblies. But then you also need a lowering kit and a major tchk tchk *BOOM* stereo.

Acetone? Lacquer thinner?

Best regards, Spehro Pefhany

IPA will do that to many kinds of acrylic.

Cheers

Phil Hobbs