This is the display i made for my alarm clock project. The first version was a 24x7 LED matrix but later changed the design for a four digits seven segment display. I decided to keep the drawings for the LED matrix and named it model A and Model B for the segment display.
The display is encapsulated in clear casting epoxy and is 5 inches wide by 2 ¼ inches high by 1 inch thick.
I was new to silicon molds and casting epoxy, so there was definitely a learning curve. I was unable to avoid the micro bubbles problem entirely. There are a few, but I can live with it, it’s not that bad. The assembly of each digits PCB, making the segments diffuser, gluing them, etc. takes a very long time. I did not want to start all over because of a few bubbles.