An overview of the matrix.
A close-up of the soldered connections. The cathodes of LEDs in a single row are soldered together, on the component-side of the board. The anodes of LEDs in a single column are soldered together at the backside of the board.
This photo makes it look much larger than it is: it is as if the board stretches all the way to the horizon... You can make out some of the soldered leads on the underside as well.
This photo shows the die inside of the LED. The small part (on the left) is the anode, the large part on the right is the cathode. Normally, the opaqueness of the plastic around the die obscures this detail.
klik thought the LEDs looked like candies...
LEDs all the way to the horizon...
klik made these photos, by the way. Thanks!