Focusing SMD led - Convex? Flat? Concave? - no edge lighting wanted.

I have made a PCB with LED indicators, pushbuttons, etc.

What is the optimum shape for the machined cavity above the LED in the underside of the acrylic? Colored stuff below...

I want it to look like a nice indicator light so the shape will determine how the operator sees the indicator. I will make a special tool to machine the shape.

I don't need or want any side lighting in the panel. Just nice looking indicators.
There are single 0805 LEDs and some have 2 0805 LEDs really close together, RED and GREEN.
When off it should just look like a cloudy round 5mm area. When on shows the color with some focusing to improve contrast. There is engraved text adjacent to the indicators. This does not need illuminating. It is just engraved through the black paint.
Viewing angle +/- 45º is OK, then reduced intensity is fine, something like looking at a standard thru-hole 3mm or 5mm LED.

3mm acrylic

top SIDE:
only some through holes

bottom SIDE:black painted, then engraved lettering from behind. Holes for pushbuttons and other plugs.
rear engraved cavity for light from LED, multiple places. WHAT SHAPED ROUND CAVITY? FLAT bottom? Convex? Concave?

middle layer 1.5mm spacer
Has windows for the LEDs and pushbuttons

bottom layer 1.6mm component PCB
All SMD max height 1.5mm. SMD 0805 LEDs


Steel panel. The above 3 layers are stacked and screwed to panel.

I don't know the answer, but suggest you experiment: try a ballnosed endmill, and try a 45 degree Vee & see which looks better.

and post pics for the rest of us :)

Fiddling around the concave seems OK. Must act like a mini Fresnel lens.
Pictures as soon as I have a workable model.

I'm also interested in seeing the outcome.

It's hard for me to wrap my mind around this project. My crystal ball isn't too clear about the description. It seems as though the materials are thin. Which means tricky routing.

Keep us posted.

Joe

Joe,

Thanks for you interest!!
ANYONE ELSE??

Neil