Tricolor LED's: how to diffuse colors.

Discussion in 'The Projects Forum' started by jrdoner, Mar 8, 2012.

  1. jrdoner

    Thread Starter New Member

    Feb 21, 2012
    I am working on a project where I want to output data by using colors generated by RGB LED's. So far, I've bought one from RadioShack, and ten more on line.

    The difficulty is that none of them mix their colors well, even though they are in a milky sort of translucent container. That makes it difficult to make yellow (and many other colors) to actually look like a homogeneous yellow color.

    Has anybody found a really good tricolor LED, or some sort of diffusing material to place over such LED's?

    Thanks in advance for any help.

    John Doner
  2. bertus


    Apr 5, 2008

    The main problem is, there are seperate chips for each color.
    You could try to scratch the RGB led with a glass-fiber pen or sand it with some fine sanding paper.
    This way the light output of the led will become more diffuse.

  3. nickelflipper

    Active Member

    Jun 2, 2010
    For color mixing the smd rgb chips do a much better job. The chinese 5050 leds are O.K., while the Cree or Osram rgb's are better yet. They can be soldered to a piece of stripboard, or a smd to dip adaptor, for breadboard work.

    I have some of those narrowly focused, chinese rgb, through hole leds...not good for close up viewing.
  4. jrdoner

    Thread Starter New Member

    Feb 21, 2012
    I have been experimenting since I posted the question. One trick that works pretty well is to encase the LED in heat-shrink tubing that just fits it, then shrink the top part of the tubing over the lens, then sand a hole through the tubing to create a small window into the LED.(about half the diameter of the original LED) When viewed off-center, this pretty well diffuses the colors, or I should say, you don't really see the inhomogeneity of the colors.

    But I'm going to try a few more variations.
  5. atferrari

    AAC Fanatic!

    Jan 6, 2004
    The sanding recommended in previous posts could be replaced (if you deem it practical) by soft paper like the one used to wrap expensive chinaware.

    In fact, depending of the power and physical location you could try different kinds of paper. Even thin opaline (common with good quality visit cards).

    Do not be affraid of experiemting with anything you happen to have around. Well... cardboard won't do...:)

    Tell you more, this trick would help the day you want to make a nice video of anytning with LEDs. Most, if not almos ALL, fail there.
  6. THE_RB

    AAC Fanatic!

    Feb 11, 2008
    The curved lense of the LED body sends the 3 colour beams out at 3 different angles.

    On the last i one I just ground the whole top of the LED flat, then the 3 colours are coming from one very small point. After that it was much easier to diffuse with a couple layers of scarred-up clear acrylic over the top. Light sanding is no good you need to gouge deep grooves in the diffuser like with a metal ruler and metal scriber point.
  7. KJ6EAD

    Senior Member

    Apr 30, 2011
    There is a commercial diffuser film called flexilum or lumiflex, something like that. For maximum diffusion use layers with space between them.
  8. atferrari

    AAC Fanatic!

    Jan 6, 2004
    Part of the trick. Yes.
  9. ErnieM

    AAC Fanatic!

    Apr 24, 2011
    Yeah, anything that diffuses the light will help here. Tissue paper to start. The Ace Hardware near me has some translucent plastic sheets that would probably work the best as it is stable, predictable, and amenableto an over sheet if need be.