COB display package: the door to the outdoor small-pitch application

The COB display has been the focus of the industry since its inception, but consistency issues are a key factor constraining its promotion. From what I have learned before, the COB package saves a lot of packaging links, which saves time and process to a certain extent, and also saves costs to a certain extent.

One of the biggest advantages of COB is that it can easily achieve high density. At present, the industry generally advocates small spacing, whether indoors or outdoors, it has set off a small gap. In the face of such industry trends, COB packaging can be easily faced.

It is understood that the COB package, ie, the chip-on-board package, is developed based on the planar technology of the glue-based solid crystal + SMD precision dispensing technology. The COB full-color product process first covers the silicon wafer mounting point with a thermally conductive epoxy resin (usually an epoxy resin with silver-doped particles) on the surface of the substrate, and then directly places the silicon wafer on the surface of the substrate, and heat-treats until the silicon wafer is firmly fixed. At the substrate, an electrical connection is then established directly between the silicon wafer and the substrate by wire bonding. This process is more simplified than the dot matrix module full color and SMD full color, so it is easy to mass production. In addition, the COB lamp bead is located at the groove on the PCB board, so it is not restricted by the size of the lamp bead, and it is easier to achieve high density.

For the miniaturization of LED display by COB, there is no bracket for COB package, and the indoor COB small pitch can break through P1.0 in the future. There is no direct size limit, as long as SMD can do it, the COB may be smaller than the surface mount.

For the most widely used 1010 lamp bead devices on the market, if mass production is available, the P1.9 and P1.8 levels can be achieved. However, if P1.2 is to be realized, there is a certain difficulty, because the smaller the dot pitch is, the higher the reliability requirement is, and it is difficult to continue to break through in miniaturization.

Faced with the technical bottlenecks and price difficulties encountered by the small outdoor gaps, there is full confidence in the outdoor small-pitch application of COB products. Because the COB packaging process first eliminates the bracketing process of the traditional packaging process, there is no longer the reflow soldering process of the lamp surface, and there is no thermal expansion of the reflow soldering furnace to break the chip wire and the chip itself. The high temperature heat shattering fails. Secondly, because the process of reflow soldering the surface-mounted lamp is omitted, the system control of the four soldering legs of the bracket is reduced. According to the reliability principle, the fewer control points of the system, the higher the reliability. Calculated per square meter, P5.0 level COB will save 160,000 solder joints, P2.0 level can save 1 million solder joints, P1.0 level can save 4 million solder joints. For the SMD packaging process, how to solve so many solder joints firstly does not appear to be a huge challenge in the case of virtual soldering, false soldering, and soldering. How to ensure that so many solder joints will not oxidize or fail in outdoor applications. Face another huge challenge. So the revolutionary step in COB packaging is because the brackets are eliminated. It can also be said that almost all the advantages of the COB packaging process are derived from this. We can move forward without such a big bag. At present, COB packaging technology can make the module-level dead light rate index reach less than five hundred thousandths, which is much higher than the industry standard of three ten thousandths.

One of the characteristics of COB packaging is that it can solve the problem of outdoor protection. Wei Qiaoshun adopted a strategy of 'rural encircling the city'. We intend to develop outdoor small spacing first. For COB, even to P3, P2.5. , P1.8, are very easy to walk, so Wei Qiaoshun intends to seize the time, seize the opportunity, first break through the outdoor small spacing, take advantage of the high reliability to return to the small penetration of the indoor penetration of the road.

The application of COB package in outdoor small spacing is mainly due to its many advantages. The most important one is all-weather excellent features: triple protection, waterproof, moisture, rot, dust, static electricity, oxidation, ultraviolet effect, and all-weather Working conditions, the temperature difference between minus 30 degrees and zero to 80 degrees can still be used normally.

As we all know, LED displays used in outdoor applications must not only have high requirements for waterproofing and moisture resistance, but also adapt to extreme weather conditions. The harsh outdoor environment puts forward higher requirements for the stability of the LED display.

In addition, the COB packaging process saves costs, mainly in terms of provincial support, provincial braiding, provincial welding, provincial freight, and simplified process saving. The higher the density, the more obvious the cost advantage.

COB can be said to be unimpeded on the road with small distance outdoors. However, in the future, can COB displays break through in outdoor small-pitch applications? The final decision on this issue is still in the market and in the hands of consumers.

Whether it is COB or SMD, the most important thing is to maintain stability when applied to outdoor LED displays! Product quality is the ultimate guarantee by the market!