Glossary A–ZLetter C
Chip on board (COB)
Chip on board is a construction method for LED walls in which the light-emitting diodes are placed directly on the circuit board as bare chips and sealed with a continuous protective layer.
There are therefore no individual LED packages. As a result, the surface of a module is smooth and closed.
The method allows very small pixel pitches and suits LED walls that are viewed from a short distance, for example in meeting rooms, control rooms or shops. The closed surface protects the diodes against knocks, dust and moisture. This is an advantage especially at the edges of modules, where individual LEDs break off easily with other designs. The surface is also easier to clean.
With chip on board, individual faulty diodes cannot simply be replaced; usually the whole module is swapped or repaired by the manufacturer. The colour of the sealing layer can vary slightly from batch to batch, so replacement modules may look different when switched off. Operators should therefore order spare modules from the same production run and check uniformity with dark content.