Just finished up a run of experiments: mixed results to be fair. Hoping to improve with time though, going to try drilling out a series of 1mm holes in the shape of a letter next time instead of just using a hand router as I did with all but one digit here.
Brightness is a problem - can't see the digits if there's strong light (fair enough, I expected that
- I was going to mount the acrylic platter against a black background anyway)
I've encountered several problems - and came up with several good practices:
-Good viewing angle (up to 60-70 degrees I reckon)
-Low visibility in bright light (to be expected really
- you
can see it, but particularly with the overhead halogen bulb it just gets drowned out by all the white light - going to try putting against a reflective or black background to see if that helps any)
-Unable to see digits near back of the platter (see photo).
-Etching gives decent brightness
-Drilling a series of 1mm holes (spaced between 0.5 and 2mm apart (from the center of the drill) gives better brightness than etching (need to be careful not to distort the acrylic plate if you're doing this! Drill against a hard material and make sure it's clamped down!
-Going to try using thinner Acrylic - acrylic must be thin (I'm using 1mm: even less, ideally 0.5mm would give a good combination of fidelity and visibility.
-Care needs to be taken when cutting and sanding edges; if the acrylic isn't cut cleanly it doesn't let a lot of light through the edges (which is where our lights are coming from!)
-Probably going to need to light it from the top as well as the bottom: or use angled lights to ensure good lighting near the top of the plate.
-Putting 30V through an LED because you had the wrong preset on your bench supply breaks the LED. Who'd have thought.
Note all pictures are taken under medium lighting conditions (1x cold cathode overhead work lamp + 1x fluorescent at other end of desk - the white balance is all over the place as well because of the visible LED at the bottom (I just used a single LED with a 1mm hole drilled in the end and some tape to try and occlude some of the ambient light)
2: drilled - 5 plates (no background)
3: etched - 5 plates (no background)
7: etched: 10 plates (black background: not light isn't focused on that plate properly, 8 is also slightly visible (can be avoided by better LED placement)
9: etched: 10 plates (seen behind 8 plates) - thickness of the plates is causing problems. Problem may be improved with drilled numbering instead of etching (as light from rear plates may travel along holes in front of it: we shall see!)
2: etched (before I tried drilling it): 10 plates (black background): note 3 is also partly visible due to bad LED Placement
3: etched: 10 plates (black background):note 2 is also partly visible due to bad LED Placement