LED array is a predetermined pattern of a number of LEDs mounted on a printed circuit board (PCB) or other surfaces, which is capable of producing light when powered. LED array? COB? People often get confused by its inconsistent names. In white light illumination context, LED array and COB often refer to the same thing. However the name “LED array” is more emphasised on the arrangement of chip in which chips are set in matrix to reach higher power in single package unit; and the name “COB” (Chip On Board) is focused on its unique encapsulation technique in which silicon chip is directly planted on the Board (PCB board) without any medium material, this is quite different if you look at other (earlier) LED packages such as Φ3mm, Φ5mm and high power LED, in which the chip is set on a reflective cup instead of being directly connected to the base.
The advantages of Chip on Board LED arrays are:
Compactness due to small size of LED chip. High intensity, particularly at close distance. High uniformity, even at close working distances. Best thermal performance for better lifetime, stability, and reliability.