LED 101 / Hardware
COB LED
Chip-on-board mounts bare LED dies under a resin skin. It is the durable fine-pitch option for close viewing, not a substitute for a mid-pitch gym wall.
COB (chip-on-board) places the LED chips directly on the substrate and covers the array with a protective resin. There is no individual SMD package with wire bonds sticking up at each pixel. The face is smoother, sealed against dust and casual contact, and better suited to pitches often under about 1.5 mm.
Compared with open fine-pitch SMD, COB takes a brush, a wipe, and light bumps with less risk of dead pixels. Contrast can be high when the surface is dark and matte. Power draw is often lower for a given brightness class. Those traits suit lobbies, boardrooms, control rooms, studios, and retail walls where people stand close.
COB is not the usual answer for a school gym scoreboard. Gym walls are typically mid-pitch SMD with an impact mask and a module lock built for balls. Mixing the two problems leads to the wrong pitch, the wrong cost, or the wrong durability story. For gym impact design see Impact-resistant LED for gymnasiums. For how DIP, SMD, and COB sit next to each other see DIP, SMD, and COB.
LUXVISION ECOLUX HD X is an example of fine-pitch COB product in pitches such as P0.7, P0.9, P1.2, and P1.5, in thin cabinets meant to sit close to the wall. HD XR adds dual redundant power and receive cards for rooms that cannot go dark on a single failure. That redundancy topic is covered under Power and data redundancy.