Vintage displays (Part 2)

  Some  earliest LED displays for military ground equipment and industrial applications:
HDSP-2490, ceramic DIP, year 1989, red LED color:

 20x optical zoom

200x

500x

500x, same picture but with different light position, light shines from above through the lens, silicon die part number 1BU9B with HP logo and photo-lithography alignment squares 

500x

500x LED crystal itself, all crystals connected into 5x7 LED matrix, similar to HDSP-2000

with 2000x we can see purple ceramic crystals and gold coating structure

300x

 HDSP-2451, year 1985, yellow LED color:

200x

500x, silicon die part number 1BU8B, ancestor of HDSP-2450 from 1989

500x, tiny wires connected with dot welding

500x

200x and LED crystal