Product
COB (Chip on Board) technology has significant advantages in the field of LED display. Its core lies in directly packaging LED chips on the substrate. This process not only eliminates the single packaging and patching required by traditional SMD (Surface-Mounted Device), but also greatly reduces the risk caused by solder joint failure, thereby improving the overall reliability and stability of the product. Due to its compact structure, COB has better vibration resistance and moisture resistance, which is very suitable for scenarios with extremely high reliability requirements, such as large outdoor display screens and industrial automation control systems. In addition, COB can achieve extremely small pixel pitch, such as a pitch value of less than 0.5 mm, which makes it unique in meeting the needs of high-density displays such as Micro LED. It is widely used in high-end display in conference rooms, virtual reality shooting, and near-eye display systems of augmented reality/virtual reality devices.
Better heat dissipation performance is also a major feature of COB, because the chip is in direct contact with the substrate, forming a shorter heat conduction path, which is particularly important for high-brightness and long-term continuous operation application scenarios. At the same time, the surface of COB is covered with a layer of encapsulation colloid, which can not only effectively prevent dust intrusion, but also reduce damage caused by accidental collisions, thereby reducing the cost and frequency of later maintenance.
Although COB technology has shown many advantages, SMD, as a mature LED packaging method, still maintains its competitiveness in many aspects. First, after years of development, the SMD industry chain has become very mature, and the equipment is highly versatile, which effectively controls the cost of large-scale production, especially in the mid- and low-end markets, such as conventional indoor and outdoor advertising screens or TV backlights. Secondly, another significant advantage of SMD is that it is easy to repair. A single damaged lamp bead can be easily replaced without replacing the entire module, which greatly reduces maintenance costs. In addition, SMD technology supports LED chips of various sizes, such as the common 2835 and 1010 models. This flexibility enables it to better adapt to the needs of different resolutions and brightness.
(1) In the short term: complementary coexistence, not complete replacement
In the high-end market, especially in the Mini/Micro LED field, as consumers' requirements for ultra-small pitch display effects and high reliability increase, COB will become more and more popular with its unique technical characteristics, and is expected to gradually replace traditional SMD and become the mainstream choice in the next few years. However, in the mid- and low-end markets, SMD will maintain its leading position due to its high cost sensitivity, especially for products with a pitch of 1.2 mm or more.
(2) In the long run: COB technological breakthroughs may accelerate substitution
If COB can achieve significant cost reductions through technological innovation in the future, such as improving packaging materials and optimizing mass transfer technology (such as using laser transfer), it will have the opportunity to further penetrate into a wider range of market levels. In addition, with the rapid development of in-vehicle displays and personal wearable devices (such as AR glasses based on Micro LED technology), COB has shown great potential in these emerging fields and may drive the entire industry to transform towards higher efficiency.
Although the prospects are bright, COB still faces some industrialization bottlenecks. The current yield rate is relatively low, repair is difficult, and it is difficult to ensure consistency between each unit. These require manufacturers to invest more resources in the development of more sophisticated equipment and technologies to optimize the production process. At the same time, the existing SMD industry chain is large and deeply rooted, with both huge existing production capacity and fixed customer group habits (including maintenance service models). These factors may slow down the speed of COB's comprehensive replacement of SMD to a certain extent.
Conclusion
In summary, COB technology is gradually establishing its position in the high-end market that pursues ultra-small pitch and high reliability, and is likely to lead the future development trend of Micro LED; but in the mid- and low-end market that focuses on cost-effectiveness, SMD will continue to play an important role due to its low price and easy maintenance. Therefore, the two technologies are most likely to form a complementary pattern of "high-end COB + mid- and low-end SMD" rather than a simple mutual replacement relationship. Which technology will eventually become the dominant force in the market depends on factors such as whether COB can quickly reduce costs, achieve key technological breakthroughs, and whether the new application scenarios are strong enough.