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I'm trying to replicate the effect of this LED panel I found at Home Depot with a different set of LEDs and use a differently sized panel. It's basically just a diffused light that mimics a window or skylight.

![light panel

It's 2x2ft and produces 4250 lumens and has selectable color temps (daylight white, bright white, soft white) with a switch-based color temp selector.

Upon inspection, I realize that it uses some type of edge lit material, but I'm not sure what. My goal is to diffuse light through the panel uniformly using an RGBW strip, maybe something like Philips Hue. I'm not sure if the panel should be clear with a backing or frosted.

What are the best materials to use for this?

Edit: I found a teardown of the panel on youtube. No identification of where the material is from exactly, but maybe will aid the answerers.

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  • \$\begingroup\$ "Edge-lit" seems like a strange design choice for something intended to provide that many lumens over a 2x2' area when an array of LEDs behind a decent diffuser typically works well... \$\endgroup\$ – brhans Jul 16 '19 at 21:25
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    \$\begingroup\$ Strange or not, they work really well. Installed two 2x4ft panels in the basement, more than doubled the available light output, and the light is very even across the entire surface. Halph, I'd suggest researching how LCD backlights work; those spread the light evenly across the whole surface but there's more than a little magic to it. \$\endgroup\$ – rdtsc Jul 16 '19 at 21:29
  • \$\begingroup\$ Dumb question: why not buy one of the panels you linked to and use the guts out of it? \$\endgroup\$ – spuck Jul 16 '19 at 22:42
  • \$\begingroup\$ Note that home depot seems to be using some stupid location blocking (it's giving an "Access Denied" response for me). Either way, it would be better to describe the effect you are looking to achieve without relying on external site anyway. That way, the question will continue to be usable even after Home Depot stops selling that product. \$\endgroup\$ – Jasper Jul 17 '19 at 8:53
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    \$\begingroup\$ Related question: electronics.stackexchange.com/q/86781/2028 \$\endgroup\$ – JYelton Jul 17 '19 at 14:48
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What are the best materials to use for this?

These panels are built in the same way as LCD monitors with LED backlight. Well, monitors have a LCD in front of the backlight panel, but you get the idea. Here's a monitor teardown.

The important part is a thick transparent acrylic plate which acts as a light guide via total internal reflection. It is lit through its edges. And... there is a pattern etched on it which breaks the total internal reflection in order to allow the light to get out through the front side. Without this, the light would only get out of the plate through the edges, and that would be useless.

The acrylic plate is the center of a sandwich, with a white reflector on the back, and one or more sheets of diffuser material in front. A LCD monitor will also have polarizers and, of course, a LCD.

All this is not DIY friendly, but you can get the whole kit for free if you find a busted LCD TV or LCD monitor. Thus... try dumpster diving. Get rid of the LCD and polarizer, and keep only the backlight plate and reflector/diffuser films.

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    \$\begingroup\$ These folks are a maker of the material: briteview.com I met their founder many years ago when they were just starting out. \$\endgroup\$ – hacktastical Jul 16 '19 at 23:01
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My company was a market-leader in LED flat panel lighting, the basic construction was similar to @peufeu's description:

  • LED strips on all four edges (metal-core PCB) bonded to the edge aluminium extrusions with thermally-conductive tape.
  • Acrylic block with the front face lightly sandblasted, the edges were just left as the basic sawn finish.
  • White plastic reflector sheet
  • Aluminium backplate, this screwed into the aluminium extrusions and held everything together. The acrylic block was prevented from falling out the front by a small lip on the aluminium extrusions.

The LED drive wires were routed out of the assembly via a small cutout in one of the extrusions, this then went to the driver which was mounted on the back.

Illuminating the edges really is the most effective way of producing a very even light with no spotting. Rear illumination invariably requires heavy diffusing.

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    \$\begingroup\$ ... and diffusion gives absorption reducing light output and efficiency. \$\endgroup\$ – Transistor Jul 17 '19 at 15:27

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