@Ross_Malyon you can buy that stuff in 8x4 sheets, but its awful stuff to work with. Its brittle, cracks easily and quite hard to work (cut, shape, bend) with. I used to make those light boxes that DJs had in front of their decks, and we used that stuff .
People will probably think its pretty lame, but White Candle wax (tallow) actually works quite nicely as a diffusion material - it is soft at 50 C and will run when its a bit hotter than that. You can stick it straight to the PCB and it looks ok. Just a little experiment while I was trying to make moulds using a lost-wax technique (I don’t have a 3d printer or scanner). Just for something stupid to do I turned on the LED and it looked ok.
The best way of diffusing something is to have it reflect off a white surface (if you want to blend all the colours). Not sure if this is practical for your needs though.The down side is you lose several stops of illumination . The distance between the light source and the diffuser is important as well.
I know in all the soft boxes I use in my photo studio the main diffuser is white rip-stop nylon.
I do have some of that industrial diffuser lens material (a 2.4m x 1.2 m sheet). It is quite expensive, hard but brittle polycarbonate. Its also extremely ugly when the LED’s are not on.
Hi all,
Thanks for your replies.
I guess I asked the wrong question — what I want is controlled diffusion. I want each pixel to look like a normal LED. Well defined and with the colour nicely mixed.
James
Put a dob of silicone caulk on each LED. It will clear when it sets.