With the rapid development of display technology, COB packaging products have become a hot new favorite in the mid-to-high-end display market recently, and are likely to become the trend of future displays. So what is COB?
At present, there are two main packaging technologies for full-color LED small-pitch displays, one is SMD surface mount component technology, and the other is COB integrated packaging technology. Surface mount components were introduced about two decades ago, ranging from passive components to active components and integrated circuits, which eventually became surface mount devices (SMDs) and can be assembled by pick and place equipment. And COB is a brand-new packaging technology that has been applied to full-color LED screens on a large scale in recent years.
SMD is the abbreviation of Surface Mounted Devices, which means: Surface Mounted Devices, which is one of the SMT (Surface Mount Technology) components. At present, indoor full-color LED screens mainly use surface mount three-in-one SMD, which refers to the packaging technology of packaging SMT lamps with three different colors of RGB LED chips in the same colloid according to a certain spacing to form a display module. .
The main process is to encapsulate the LED light-emitting chip in a bracket to form lamp beads (SMD surface mount parts), and the lamp beads are then attached to the PCB board through soldering. Then put the surface mount parts and the PCB board into a high temperature oven for sintering and solidification (reflow soldering), then wire the LEDs by pressure welding technology, and finally use epoxy resin to dispense and encapsulate the bracket, and finally form a display module. The modules are then spliced into units.
COB is short for Chip On Board. It means: chip-on-board packaging technology; a semiconductor packaging process in which the chip is adhered to the interconnect substrate with conductive or non-conductive glue, and then wire-bonded to achieve its electrical connection. Simply put, it is to mount the light-emitting chip directly on the PCB without brackets and solder pins. Compared with the traditional SMD method, the COB package omits the two major processes of making LED chips into lamp beads and reflow soldering. The chip is directly assembled to the PCB. Basically, there is no restriction on the size of the packaged device, and a smaller dot pitch arrangement can be achieved. Currently, Micro LEDs all use COB technology.
