Lighting Design

posted Jul 14, 2012, 12:36 AM by Andrew Stock   [ updated Jul 14, 2012, 12:36 AM ]
So, in the bits of spare time I have had over the course of this week, I have been thinking about some of the functional intricacies of the focus of my case... lighting! One of the primary light features will be the front of the case, which will be backed by frosted acrylic that will be edge lit to give it a soft glowing effect. The light will be provided by some RGB light strip that I purchased a while ago, and controlled by an Arduino... but that is still 'in development'... so to test, I dissected one of those silly LED lit pens that they give away at trade shows. :P

The first test shows, as expected, that light is not diffused in Acrylic very well by default. The edges light up, but that's about it.

So, to help spread the light, I sanded each side of the piece with some 200 grit sandpaper. Enough to scuff it up pretty good. The change is dramatic.

But... still not enough. The color doesn't quite reach the edges, and is a lot brighter at the origination point than anywhere else. I read up a while ago that drilling an inlay hole to embed the light source in would help increase the light absorbed by the acrylic, so I gave that a shot:

Looking better! But still not quite there. What else can I do? Hmm... perhaps backing it with some material to help contain the light? Here's a shot with some simple printer paper held against the back:

Now we're getting somewhere. Just to try it out, I also put some scrap shiny aluminum behind it, to see what that did:

Eh, not that great. A step backward from white paper. I'm not sure that putting white paper behind my acrylic is the right answer either... but it's on the right track. Perhaps painting the back surface? Hmm. 

Anyway, here's a rough preview of how the lit acrylic looks in the case:

And here's how it looks with the LED inlaid in the side of the acrylic:

Keep in mind this is with a singe LED, and it will be lit all the way around with a strip that has LED's every 2 inches. So it should be much brighter/fuller. 

Anyway, on to the thin edge-lit strips that will be featured along the sides of the case! Here was the first shot with the LED embedded into the surface, and no backings:

Not very good. 

Next, I set the thing on a piece of white paper:

A little better... but not much. Next, a sheet of paper on each side:

That made quite a difference! Just to try it out, I also backed one side with aluminum:

Meh. Not great. Not as good as double paper, but close. 

So, right now it looks like paper (or at least a white surface) is the clear winner for getting light to diffuse. One other thing I am interested in trying is a mirrored surface... they make 1/8" acrylic mirror sheets, and i think that might significantly increase the amount of light reflected back into the acrylic. Worth picking up a sheet to find out, anyway! 

Next time... some shots of fabricating the front reservoir housing! See you then!