Analysis of characteristics and advantages of COB small pitch LED screen

For the small-pitch LED screen of COB technology, there are many "misunderstandings" on the market. On the one hand, many people think that this is an "expensive" technology; on the other hand, many people think that surface-mount technology is "enough", and new technology may not have much future. However, since 2016, the development of COB small spacing, especially in the high-end market, has shown that “technical innovation has no limits”!

Domestic LED packaging and testing enterprises have entered a large-scale expansion cycle since the second half of 2015. A considerable part of the new capacity is arranged in the COB packaging technology. This is not only because of the accelerated development of COB LED display applications, including lighting applications and backlight applications for televisions, but also into the era of COB chip-level packaging. At the level of basic LED wafer manufacturers, the development of small-particle high-brightness crystals is also becoming more and more abundant. Taiwanese companies pay special attention to the market potential of the latter, and believe that MIN-LED technology will be one of the main directions of the short-term LED application incremental market.

It can be said that the rise of COB technology is not a single person's single fight, but the resonance of the entire industry chain. From upstream wafers, packaging to downstream applications, and equipment and materials manufacturers, they are supporting the development of COB products.

The comprehensive optimism of the industrial chain will inevitably mean that COB technology has its own unique advantages - these advantages are also the key to the large-screen market, COB products can quickly land.

First of all, the large screen of COB technology is better in stability. On the one hand, the COB technology is a chip-scale package, and the LED crystal particles directly contact the PCB board (whether in formal or flip-chip), which increases the available heat conduction area of ​​the LED crystal and improves the heat dissipation capability. At the same time, this chip-level packaging method is “completely covered”, which puts a 100% protective armor on the LED crystal, which is good for moisture and bump prevention.

On the other hand, COB packaging technology does not require a reflow process for surface-mount LED display products. The reflow process is a higher temperature soldering process. LED crystals are temperature sensitive. The reflow process is actually the biggest factor in the LED lamp product dead Light and lamp life reduction. COB is precisely because the reflow process is not required, so its dead light rate is only one tenth of the surface mount process, and the stability is greatly improved.

"For LED large-screen applications, especially command and dispatch centers, stability and reliability are the core requirements." WeChuang believes that this is precisely the point that COB technology has absolute say in the high-end small-pitch LED application market.

Second, for audiovisual engineering, visual experience is also an important "selection point." The COB small pitch technology features chip-scale packaging and full coverage of optical resins. Compared with the traditional surface-mounted lamp beads, this structure has great differences in image quality.

The high brightness of the LED screen is an advantage, but it is also a disadvantage of indoor applications. High-brightness glare, high-frequency refreshing vertigo, and the grainy feel of the lamp bead surface make the LED screen face the application of “high distance and long viewing time” in the high-end command and dispatch center, which is especially “easy to visual fatigue”. The latter is a drawback that many customers cannot accept. The COB small pitch technology can well eliminate the "visual experience disadvantage" of these traditional LED screens.

The COB package achieves better video optical performance through chip-level packaging. The picture quality is more comfortable and soft, and there is no significant pixel graininess. It is more suitable for “closer distance”, “indoor ambient light” and “longer time”. Long-term viewing" applications under conditions. For this advantage, Lian Shuo described it as “contrast with COB”, which fully illustrates the market experience advantage of COB products.

"Higher stability, reliability", "better look and feel" is the "reality" support point for COB small pitch to become the next generation product standard. However, this is not the full advantage of COB technology.