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how do I give an LED a wider beam spread? Answered

I would like to position a 5mm LED approx 3mm - 5mm behind a clear surface with a stencil in front of it. at the moment the LED projects a spot about 5 - 8mm in diameter, I'd like to make that around 20mm without changing the LED's position.
 I can replace the LED's, so if experimentation of the focal lens is required thats OK, but every time I've tried I'm made something with a dark area in the middle ;-)


Scratch a clear piece of plastic with fine sand paper and put that over the led as a diffuser.  Then make a cone of alum. foil, shiny side in, so that all the led light gets projected back to your stencil.  Diffusing the led will cause some light to be lost.

Cover the tip of the led with a spherical blob of hot glue.  Tada - scattered beam :D

Cutting the end of the LED off so it is flat instead of rounded often gives a good effect. Saw it off with a hacksaw then file it down with some medium sandpaper then fine sand paper.

You could find a LED with a wider angle, or use more. But another option would be to diffuse the light by roughening-up the plastic case with coarse sandpaper.



8 years ago

See if you can get a cheap, generic pair of reading glasses. They're usually available at pharmacies. Try one of the lenses in front of the LED, maybe that will do the trick.