Diffuser for WS2812b style LEDs for use as panel indicators - Page 1
Forum section: electronics / general

author: e100
author_rank: Frequent Contributor
timestamp: March 29, 2024, 04:47:30 am
content: I'm trying to use these as individual panel indicators instead of their intended purpose as room & entertainment lights.There are mm sized gaps between the red, green and blue emitters and the built in lens makes no attempt to diffuse the light, the assumption being that these will viewed from a distance behind a silicone rubber or plastic diffuser.In my application as panel indicators they will be at desk level and run at a low brightness level. When using individual R G B emitters it looks OK, however when mixing colors you can clearly see the individual emitters instead of an even color mix.I need a separate diffuser for each one so that light from one device doesn't bleed through to adjacent devicesHas anyone seen anything that could so the job?I sort of imagine it being like a cylinder of translucent silicone rubber that you glue onto the top of the device.

author: Kean
author_rank: Unknown
timestamp: March 29, 2024, 05:09:45 am
content: Maybe some short but wide light pipes? They will diffuse the light, but longer will likely be better.Look for a part like Bivar PLP5. These can be found on Digikey, but also cheaper copies on AliExpress.e.g.https://www.aliexpress.com/item/32962156618.htmlI've used some 19mm long 3mm diameter light pipes from this seller, and mount them in a 3D printed holder to help alignment and reduce bleed.I also 3D printed a jig for drilling the front panel holes in the plastic enclosure. Marking and center punching alone lead to noticeably poor alignment, and I was too lazy to build a jig for the CNC.

author: Claude
author_rank: Newbie
timestamp: March 30, 2024, 04:06:14 pm
content: you need some pmma milky color, (3 to 5mm thick), distance from LED to diffuser must be something in the 10mm range if you want all 3 LEDs to mix with good result. You shall make some test. (this can be shortened using specific diffuser, like the one used to distribute the backlight on LCD display)Another way to shorten this distance is to use smaller WS2812, WS2812 exist in 2020 or even 1313 package, this help a lot to get a nice continuous tone.

author: Kasper
author_rank: Frequent Contributor
timestamp: April 02, 2024, 12:58:27 am
content: Parchment paper works. Best to have some distance between paper and LED. Not sure how long it lasts though. Probably better to use an opaque plastic. FacFox aka FF3DM made custom ones for me years ago.

author: Kean
author_rank: Unknown
timestamp: April 05, 2024, 12:48:26 pm
content: Quote from: Claude on March 30, 2024, 04:06:14 pmThe problem with diffusing the light like this is that you'll get bleed between the LEDs. The OP wants to diffuse the light but keep each indicator colour separate.One option is to laser cut cylinders from such "opal" semi-transparent PMMA and mount them with some kind of separator like a black 3D printed housing.

author: tooki
author_rank: Super Contributor
timestamp: April 06, 2024, 12:44:26 pm
content: Just get light pipes (I’ve used the round ones that just press into a hole) that have a matte finish, press them in, and then put black tubing onto them to prevent bleed from adjacent LEDs. For this application you wouldn’t want them too thin.You can also use tubing without a light pipe (in which case opaque white is ideal) to act as a light guide and baffle. Then you need some kind of diffuser on the panel. One thing I experimented with was to drill small holes in an aluminum front panel, then use a heat gun to heat the aluminum. Then I pressed a hot melt glue stick into the back of the panel, causing it to melt into the holes. After cooling, I used a scalpel to trim the excess from the front. Then I hit the front with hot air again, just for a second, to smooth the cut surface again. The end result is fantastic, using standard milky hot melt glue. This combined with a 3D-printed baffle produces superb results with RGB LEDs.