Packaging Technology:The Difference Between COB and SMD

We know that after the end of the direct plug era, we have entered the 15-year surface-mount SMD packaging era. SMD has good color mixing and is easy to operate. What are the advantages and disadvantages of COB now compared with SMD ?

Packaging Technology Comparison

The COB panel adopts the 2.0 version of the LED display panel manufacturing technology – the tradition of bracket-free integrated packaging panel technology.

The LED display panel adopts the 1.0 version of the LED display panel manufacturing technology–SMT welding panel integration technology after the packaged device with bracket is packaged.

The difference between the two technologies in solving the problem of panel pixel failure is: COB panel is a million-level manufacturing technology, which is equivalent to the concept of LCD. The product made does not need to think about how to repair the lamp when it is dead, because its pixels are invalid. The rate index is much higher than the industry standard, which can erase the bad influence of many dead lights in the LED display industry from the customer’s subconscious. Because the traditional LED display panel is a 10,000-level manufacturing technology, it is not surprising to repair the dead lamp. Therefore, comparing the two panel packaging technologies, there is a difference of two orders of magnitude in technology.

Pixel microcirculation system comparison

After each pixel of the COB panel is packaged, it is a well-sealed microcirculation system, and its electrical function and heat dissipation function are realized by the internal circuit of the colloid. It is a real closed system, and it is impossible to provide opening opportunities for any components.

No matter how well the airtight performance of each lamp bead of the traditional LED display panel is, its electrical function and heat dissipation function require that the LED chip circuit inside the bracket and the pins outside the bracket are correspondingly connected, and the external pins are ultimately To be soldered to the pads of the lamp positions on the PCB board. In fact, it is a truly open system that cannot be closed. After the single lamp device is packaged, the LED chip has a complex problem of secondary transfer, so there are too many uncertain factors that will affect the dead lamp of the panel lamp bead.

Quantized Macro System Comparison

To evaluate the reliability of a macro system, it is necessary to study and compare the number of factors that affect reliability in the system. Under the same other conditions, the fewer the factors, the higher the reliability.

The 1.2K display system COB display panel can reduce at least 8847360 influencing factors than the traditional LED display panel. The 2K display system has 2,211,840 pixels, and the traditional LED display panel has more than 8 million factors that affect reliability. If it is calculated according to the current industry-required pixel failure rate standard of 1/10,000, the allowable failure pixel is only 1/10,000. It can be as high as 221, which is obviously unacceptable to customers. But is there a way to fix it?

We will push back according to this standard. To achieve such a low standard of 1/10,000, we need an ultra-advanced panel manufacturing technology capability of 1-221/8847360)=0.999975. However, it is impossible to achieve with the current level of manufacturing technology in the industry, so there is a paradox between standards and manufacturing capabilities in traditional panel technology, so the questions raised are unsolvable. The same is true for the 4K and 8K systems below. To achieve the current level of COB display panel manufacturing of millions of panels can be said to be a fantasy.

The 2.4K display system COB panel can reduce at least 35,389,440 influencing factors compared to the traditional LED display panel, while the traditional LED display panel has more than 25 million influencing factors.

The 3.8K display system COB panel can reduce at least 141,557,760 influencing factors compared to the traditional LED display panel, while the traditional LED display panel has more than 140 million influencing factors. After doing the math, you can understand why you should buy a COB display panel no matter how much money you spend, because it is the product that really allows you to consume the lowest consumption in the entire product life cycle. If the product life cycle of the COB display panel is eight years, the lowest consumption concept is that the price of the product + the after-sales maintenance cost of the product is the lowest. There is no technology that can eliminate 100% of the reliability factors of the millions, tens of millions or billions of traditional LED display panels. So a system using traditional panel technology, the larger the pixel resolution, the more problems there are.

Systems larger than 8K are very common in the field of LED displays, but people have not considered that factors affecting reliability can be quantified, let alone using traditional processes to make LED displays. The industry’s 1/10000 pixel failure rate standard is an unsolvable technology. Even if I don’t say it, everyone knows what technology products to buy.

Comparison of heat dissipation performance

The quality of heat dissipation directly affects the life of LED products. If you don’t study the technical source of the product, it is a rogue to say that the product has a long life.

The positive and negative poles of the LED chip of the COB display panel are directly connected to the circuit on the PCB . The thermal conduction path is the shortest, there is no intermediate medium, and the thermal resistance value is the smallest. It is the most perfect heat dissipation optimization technology.

The positive and negative poles of the LED chip of the traditional LED display panel are first connected to the bracket pins through the circuit inside the bracket, and then welded to the circuit of the PCB, which is an indirect heat dissipation method. The heat conduction path is long, the intermediate medium is indispensable, and the thermal resistance value is high.

It’s really not a good cooling technique by comparison. However, for this already overwhelmed technology, someone sealed its surface with a layer of glue, naming it a GOB panel or a panel of other technologies. Once the heat and pressure inside are eroded, it expands.

Protection performance comparison

The comparison of protective performance is directly reflected in whether the product can reach the civilian level.Products that can’t stand up to the wind and rain will not become popular. COB display panel is a technology with the best protection level so far, which is mainly reflected in the following two points:

1.The anti-collision ability is an important indicator to measure the positive pressure index and side thrust that a single lamp bead can withstand. So far, no technology can surpass it.

2.All-weather capability COB display panel lamp beads already have IP65 protection capability when the glue is sealed, whether it is indoor or outdoor application.

For outdoor applications, COB display panels only need to do a simple panel protection process. The parameters of traditional LED display panels are rare anti-bump indicators. Even if they can be found, the gap is still an order of magnitude, which cannot be compared with the data of COB display panels. The glue pouring process of its outdoor panel does not have the technology to effectively detect the glue pouring dead zone under the bracket and detect the micro-bubbles generated around the bracket pins. At present, only visual inspection can be relied on, so it is considered a technology that cannot be reliably used outdoors for a long time. In addition to rain and humidity in outdoor applications, the aging impact of environmental temperature and screen temperature changes on the protective colloid, and the erosive effect of chemically polluted air on the glue protective layer of the LED panel. Therefore, it is necessary to have theories, technical process capabilities and process index detection methods that can prove long-term and reliable application.

At this point, it is not difficult for everyone to understand the reason why the traditional LED display panel and COB display panel technology are two orders of magnitude different. What needs to be explained here is that the million level is only the starting level for the COB display panel manufacturing technology. The room for improvement is two million or three million. The optimization technology of traditional LED display panels can also be improved, but its improvement space is limited, only 20,000 or 30,000. This is determined by the genetic thinking and theory of technology.

Differentiating features of COB display panels:

  1. Ultra thin and light
  2. Nearly 180° large viewing angle
  3. Can be greatly bent
  4. The wind-permeable and light-transmitting panel does not need to add glass, and the display screen is 100% free of interference.
  5. No mask

The traditional LED display panel manufacturing technology theory has influenced and dominated the development of the industry for more than 30 years. The COB integrated packaging technology theory is leading and influencing the future development direction of the industry, because it is not a simple generation technology, its innovative Theory will dominate the industry for decades.

If you need a COB led display, then the cob led display from BAITRONICS is recommended because it always stands out for its quality.

BAITRONICS-cob and smd technology

Small pixel cob led screen-BAITRONICS HD

BAITRONICS-cob and smd technology

Micro cob LED screen-BAITRONICS UHD