Light emitting diodes date back to the early 1960s. However, for decades LEDs did not have many practical applications due to their manufacturing cost. ... An SMD LED is a surface-mount LED that reduces the size of the light while at the same time adding more colors to a single LED.
One of the most recent developments in LED, COB or “Chip on Board” technology is a step forward more efficient energy use.Like the SMD, COP chips also have multiple diodes on the same surface. But the difference between LED light COB and SMD is that COB LEDs have more diodes. COB chips typically have 9 or more diodes.