In foreign countries, Sony’s recently launched new product, known as the reduced version of the LED display, is a miniature display with self-luminous features that do not require a backlight. It has the advantages of energy saving, simple structure, small size, and thin profile, and the screen is very delicate. There is no ink color problem, and with such powerful functions, COB packaging technology has to be mentioned. COB packaging is chip on board. The technology uses conductive or non-conductive glue to attach the bare chip to the interconnect substrate, and then performs wire bonding. Realize its electrical connection. The application of COB packaging technology to LED displays will undoubtedly promote the LED display industry.

To borrow a word from industry insiders, COB packaging technology is tailor-made for small pitches. Although tailor-made, it is not perfect. COB has the following challenges: First of all, in terms of technology, COB packaging screen ink color It is not easy to control, that is, when the lamp is not lit, the problem of inconsistent ink color on the surface and the flaws of the COB display package are that the overall appearance is not beautified enough. If these problems are not solved, it will be difficult to get the customer's approval. Secondly, in terms of the market, less than 10 domestic companies have applied COB packaging technology to achieve mass production on different products. The scale is relatively small, the overall market has not yet opened, and the price of traditional technology does not have an advantage. In the case of low output, Only by raising the price can survival be ensured. The third is in terms of capital. When the state cancels equipment subsidies, a large amount of capital is needed to purchase equipment.

COB packaging technology can gain a foothold in the LED display industry, so it has certain advantages.

First, COB packaging technology does not have reflow soldering and pasting lamps in the processing technology. Even if there is a later reflow soldering and pasting IC process, the diode chip has been encapsulated and cured with epoxy resin to protect it, which avoids the high temperature soldering in the soldering machine. As a result, there is a gap between the lamp bead bracket and the epoxy resin, so COB packaging technology products are not prone to dead lights after they leave the factory.

Second, the COB package has no bracket welding. The LED chip is sealed in the lamp position by epoxy resin, so it can be bent arbitrarily. The bending capacity is determined by the size of the module and the thickness of the PCB.

Third, it is anti-collision, waterproof, moisture-proof, dust-proof, oil-proof, anti-oxidation, anti-static, and the surface of the COB module light board no longer uses a mask, so it can be washed directly with water after a period of use and pollution outdoors.

As the saying goes, "Gold always shines." How does the "gold" of COB packaging technology shine?

For example, in the rental screen, the rental screen needs to be repeatedly installed, disassembled and transported. If the damage caused by collision and vibration cannot be effectively prevented, the rental screen will be invincible. COB can help the rental screen by using epoxy resin and chips. , The highly integrated bonding molding of the PCB board can effectively protect the stability of the chip and the electrical connection part of the chip. The compressive strength can reach 8.4kgmm2, and the impact strength can reach 6.8kgcmcm2.

In addition, COB packaging technology uses the advantage of being able to bend arbitrarily, and can easily produce LED curved screens, circular screens, and wave-shaped screens. It is an ideal substrate for personalized screens in bars and nightclubs. The high-density P4 series of modules are cylindrical. The bending capacity can reach 50cm in diameter. It is an ideal substrate for cylindrical media in airports, stations, and shopping malls.

As another emerging technology in the display industry after SMD, COB has attracted widespread attention since its birth. But it's just attention. Only a few companies have been trying and insisting, and most companies are conservative and wait-and-see. Driven by the demand for smaller and smaller pitches, traditional surface mount technology has become increasingly incapable. The CLEDIS technology launched by Sony for ten years and one year has proven to be a very promising solution. It has occupied the technological commanding heights in the field of small-pitch dense packaging. Is the domestic LED display industry following Sony’s pace, or is it to forge ahead with the existing domestic COB integrated packaging technology?