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| LED display with SMD and cob technology for led video wall | ||||
| There are three packaging methods for LED display screen: dip, SMD and cob. Dip is mainly a monochrome screen, which is not widely used now, and is mainly full-color. At present, there are two packaging technology forms for full-color LED small spacing display screen, one is SMD surface mount component technology, the other is cob integrated packaging technology, and cob is a brand-new packaging technology that has been widely used in full-color LED screen in recent years. LED display screen SMD and cob, the difference between SMD and cob Let's take a look at the differences between SMD led display and cob packaging of LED display: SMD packaging technology SMD: it is the abbreviation of surface mounted devices, which means surface mounted devices. It is one of SMT (surface mount technology) components. At present, the indoor full-color LED screen mainly adopts the surface paste three in one SMD. The main process flow is to package the LED light-emitting chip in the bracket to form a lamp bead (SMD surface paste), and the lamp bead is pasted on the PCB board through solder. Then the surface mount and PCB board are put into a high-temperature oven for sintering and solidification (reflow soldering), and then the LED leads are welded by pressure welding technology. Finally, the bracket is coated with epoxy resin to form a display module. The module is then spliced into a unit, that is, the packaging process is: solid crystal - welding wire - dispensing - spectroscopic tape - patch - aging - correction. Core materials of SMD process: Support: conductive, supporting and radiating. It is mostly formed by electroplating of support material. It is composed of five layers of material, copper, nickel, copper and silver from the inside to the outside. LED chip: the chip is the main component material of LED lamp, which is a luminous semiconductor material. Conducting wire: connect the wafer pad (welding pad) to the support and make it conductive. Epoxy resin: protect the internal structure of the lamp bead, and slightly change the luminous color, brightness and angle of the lamp bead; Cob packaging technology Cob: abbreviation for chip on board. On board chip packaging technology; That is, a semiconductor packaging process in which a chip is adhered to an interconnect substrate with conductive or non-conductive adhesive, and then wire bonding is performed to realize its electrical connection. To put it simply, the light-emitting chip is directly mounted on the PCB board without the need for a bracket and solder pins. Compared with the traditional SMD method, cob packaging omits the two major processes of LED chip manufacturing into lamp beads and reflow soldering. The chip is directly assembled to the PCB. Basically, there is no limitation on the size of packaged devices, and smaller dot spacing arrangement can be realized. Currently, micro LEDs use cob technology. The cob packaging process is: solid crystal - bonding wire - sealant - aging - correction. To sum up, there are two packaging methods for LED display: SMD and cob. Cob has become a trend. It does not need brackets and soldering wires without reflow soldering, which enhances product reliability and reduces packaging processes and materials. In addition, cob packaging can reduce the dot spacing of LED display. In pursuit of ultra-high definition display in the future, cob is the mainstream. |
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