Using the laser cutter, I made holes in the acrylic to fit the LEDs.
The LEDs have the pads on the ends, and are slightly longer (3.5 mm) than the acrylic is thick (3.2 mm).
Because the connector pads of the SMD LEDs stick out of the surface of the acrylic, it is possible to connect them all using one piece of pcb copper on each side.
It turned out quite nice and beautiful.
Step 1: Drawing and cutting it up
I made the holes the exact size of the LEDs, to make the just squeeze in nice and snug.
I cut up the acrylic shapes in the laser.
And the pcb copper parts in the cnc router.
Step 2: Mounting the LEDs
Make sure to mount the LEDs the same way up/down, as they have polarity.
The LEDs have a little notch, showing the plus side.
Step 3: Making the sandwich
I used some old double sided pcb copper sheets.
A 3 mm screw hold it all together.
The sandwich is held together firmly by the screw, wich ensures, that the pcb flex and all the ends of the smd-LEDs are getting connected.
Step 4: Electrical connection
I added a little extra solder just for the looks.
Step 5: Mounting cable
The bottom copper layer is getting connected through the screw, that hold the sandwich together.
Note the circular groove in the copper, that isolates the center (connected to the back) and the front.