In recent years, with the rapid development of small space LED display market, LED display manufacturers have developed new packaging modes, mini led, cob and micro led. These new packaging modes are better than traditional SMD packaging in terms of display performance and stability. So what are the advantages, disadvantages and development bottlenecks of cob small spacing LED display? The following is a brief introduction of the mini photoelectric LED display manufacturers.
COB package is an integrated package of LED display module, the surface of the module is led beads, that is, pixels. At the bottom are IC driving elements, and then these cob display modules are spliced into LED displays of different sizes.
Advantages of cob small space LED display packaging
Cob does not have the diameter of a single lamp body, which is smaller than the chip size of traditional SMD package. Therefore, the LED display with smaller spacing can be packaged, and the spacing can be less than 1.0 mm. The traditional SMD package can only achieve 1.25 mm.
Technically, compared with SMD, cob has no bracket, so it can reduce the cost, simplify the manufacturing process, reduce the chip thermal resistance and achieve high-density packaging. And cob is directly embedded in the PCB board, so it will not be welded on the PCB board like the traditional SMD, the lamp beads are easy to be knocked off, and the false soldering rate and dead lamp rate are high. Because cob does not need welding, it can reduce the welding cost, and its stability is higher, the lamp bead is not easy to be knocked off, and the dead lamp and false welding rate are also lower.
Cob small spacing LED display can select different thickness PCB board according to customer demand, and its thickness is 0.4-1.2mm. Compared with the traditional SMD packaging module, it is lighter and thinner, which can reduce the installation structure, transportation and engineering costs. It is suitable for many ultra-thin LED display applications, or wall display.
The packaging method is that the LED chip is directly packaged in the concave lamp position of the PCB board, and then cured with epoxy resin glue. The surface of the lamp point is convex into a spherical surface, which is smooth and hard, impact resistant and wear-resistant. Its viewing angle can reach 175-180 degrees, and it has better optical diffuse haze effect.
Because cob encapsulates the lamp beads on the PCB board, the heat of the lamp wick can be quickly transferred out through the copper foil on the PCB board, and the thickness of the copper foil on the PCB board has strict process requirements. In addition, the gold deposition process can greatly reduce the light attenuation. To a certain extent, it can extend the service life of LED display, and its dead light rate is also greatly reduced.
Although the surface of the mask can be cleaned without water or dust. Combined with triple protection technology, cob small spacing LED display has the effect of waterproof, dust-proof, moisture-proof, anti-corrosion, anti-oxidation, anti ultraviolet and anti-static. It can be used in the environment of minus 30 degrees to above 80 degrees, and meet all day working conditions.
Cob small space LED display development bottleneck
Once the cob lamp is repaired, the cost of replacing the lamp is relatively high due to the phenomenon of solder bead. Moreover, the one-time pass rate of the package is not high, the contrast is low, and the color uniformity of the display is not as good as that of the SMD packaged LED display.
Most of the existing cob packages still use front mount chips, which need wire bonding process and solid crystal. However, there are many problems in wire bonding, and the process difficulty is inversely proportional to the pad area. In addition, compared with SMD, its raw material cost is higher. Therefore, the manufacturing cost is relatively high.
Although cob small spacing LED display packaging technology has been developed to a certain extent, due to the high cost and other factors, the products are not widely used in the market. SMD is the main packaging for the small spacing LED display screen with point spacing less than 1.0 mm. Relatively speaking, SMD packaging of small spacing LED display has lower cost, higher contrast and more uniform display color.