COB packaging has gradually become the new favorite of small-pitch LEDs
In recent years, with the rapid growth of small-pitch LED display products, small-pitch LED display technology is also making continuous progress. Recently, a new type of packaging form, COB (chip-on-board) packaging products, has gradually become a hot packaging situation due to its unique process and product characteristics…
COB (Chip On Board), that is, the RGB chip packaged on the circuit board, is a new full-color LED technology developed based on the planar technology of solid die and precise dispensing technology. In the COB product process, the PCB board is first patched with IC, and then the chip is fixedly placed on the surface of the substrate, and then an electrical connection is established between the chip and the substrate by wire bonding, and after passing the inspection, glue is dispensed and sealed to become a A LED full color module. It has the following advantages:
Compared with the traditional surface mount LED display, the COB technology display is more stable and simpler.
During the reflow soldering process of the traditional surface mount LED display, due to the different expansion coefficients of the SMD lamp bead bracket and epoxy resin under high temperature, it is very easy to cause the bracket and the epoxy resin encapsulation shell to fall off, and gaps appear. The phenomenon of dead lights is prone to occur, resulting in a high defect rate. The COB technology display is more stable, because the processing technology does not need to go through reflow soldering to paste the lamp, which avoids the problem of gaps between the lamp bead bracket and the epoxy resin caused by high temperature soldering in the welding machine, so COB products are not easy after leaving the factory. There is a dead light phenomenon. In addition, the unique packaging method of COB also effectively protects the light-emitting diode and enhances its resistance.
COB products encapsulate the lights on the PCB board, so the heat dissipation is directly through the PCB board, the heat is easily dissipated, and it will hardly cause serious light attenuation, so there are few dead lights, which greatly prolongs the life of the display. The traditional surface mount LED product chip is fixed in the bowl, not in direct contact with the PCB board. It mainly dissipates heat through the colloid and four pads. The heat dissipation area is small, and the heat will be concentrated in the chip, which will cause serious light attenuation for a long time. Even the dead light phenomenon reduces the service life and quality of the display screen.
The COB process small-pitch LED display has the properties of anti-collision, waterproof and moisture-proof, dust-proof, oil-proof, anti-oxidation and anti-static, so it has the characteristics of wear resistance and easy cleaning. The surface of the lamp point is raised into a spherical surface, which is smooth and hard, and is resistant to impact and wear; if there is a dead point, it can be repaired point by point. Since there is no mask, the surface is smooth and smooth, and the surface stains can be cleaned with water or cloth.
The COB display adopts large-chip light-emitting diodes, which can effectively improve the brightness, and the heat dissipation is even, the brightness attenuation coefficient is small, and it can maintain a good consistency after long-term use. The technicians use a 480*480mm cabinet, and when the brightness is 1000nit, the energy consumption of COB-P2.5 and SMD-P2.5 is compared. The COB power consumption is 80.57W and the SMD power consumption is 165.7W. It can be concluded that the same brightness is emitted. , COB heat dissipation is smaller, more energy saving.
COB packaging technology has significant advantages in stability, luminous effect, durability, power consumption, etc., and has emerged in the LED display market, especially in the field of outdoor small-pitch LED packaging. The excellent effect of COB has been recognized by the market one after another.