In addition to good heat dissipation and low cost, the COB light source can also be customized. However, in terms of technology, COB packaging still has shortcomings such as light decay, short life, and poor reliability. If it can be solved, it will be one of the leading directions for future packaging development.

COB packaging technology is to directly weld the light-emitting chip on the PCB board, and then cover the whole to form a unit module, and finally splice it into a whole LED screen. The COB screen is a surface light source, so the visual perception of the COB screen is better, without graininess, and it is more suitable for long-term close viewing. When viewed from the front, the viewing effect of the COB screen is closer to that of an LCD screen, with brighter colors and better details.

COB not only solves the physical limit problem of traditional SMD (the dot pitch can be lowered to less than 0.9, which meets the needs of new display Mini / Micro LED), but also enhances product stability and reliability, especially in the field of Micro LED applications. Dominant position, the prospect is very broad.

COB products are mainly used in the commercial lighting market. With the improvement of technology, the performance of high-power COB products tends to be stable. Recently, they have been gradually used in outdoor lighting, including LED high bay lights, street lights and other markets. Because high-power LEDs and COB LEDs have product design advantages and high light intensity that medium-power LEDs do not have, they will enhance their competitive advantages in the high-end lighting market.

First of all, in the high-end commercial lighting market, lighting is used in exhibition spaces such as museums and art galleries, mainly downlights, projection lights and reflector lights. In addition, vehicle COB is also one of the application fields of COB. However, because the COB market itself is a niche market with a small volume, and automotive COB is one of the branches of this niche market, the industry pays less attention to it. However, as many COB manufacturers began to enter the automotive COB market on a large scale, automotive COB quickly became the main battlefield of the price war.

In addition, industrial lighting brings new opportunities to small and medium-sized COB companies. According to research data, LED industrial lighting will grow rapidly in the next few years. At the same time, since most industrial lighting uses invisible engineering channels, price wars and scale wars can be avoided.

COB packaging saves the process of light separation, color separation, drying, etc. The most critical difference is to remove the soldering process. During the soldering process of SMD, it is extremely difficult to control the temperature. If the temperature is too high, it will cause damage to the lamp. Low, the solder is not completely melted. It is easy to cause false welding, false welding and other phenomena, which is a big challenge for the stability of the lamp bead. And COB does not have this process, so the stability will be greatly improved. The processing technology of the traditional LED display screen is relatively various, especially in the process of reflow soldering, the expansion coefficient of the SMD lamp bead bracket and the epoxy resin are not the same under the high temperature state, which can easily cause the bracket and the epoxy resin package to fall off, appearing There are gaps, and the phenomenon of dead lights gradually appears in the later use, resulting in a high defect rate. The reason why the COB display is more stable is that there is no reflow soldering lamp in the processing technology. Even if there is a later reflow soldering IC process, the diode chip has been cured and protected with epoxy resin glue, which avoids soldering. There is a gap between the lamp bead bracket and the epoxy resin caused by high temperature soldering in the machine. Therefore, this is also one of the keys that COB will be well applied.

At present, Mini LED display products with COB packaging technology are gradually increasing. In recent years, indoor small and micro-pitch projects have been widely used, and medium and large-sized standardized display devices such as LED all-in-one machines and LED TVs have a strong growth momentum. Another new display technology product of COB packaging technology, Micro LED, is about to enter the mass production stage. After the global economy recovers, the market for COB-relate

d technology products may usher in greater opportunities for development.

Due to the high threshold of COB packaging production process, it has not been widely used in the whole country, so the future market prospect is still promising, but if manufacturers want to seize this opportunity, they still have to continuously improve their technical level.

Compared with traditional packaging technology, the advantages of COB technology include:

1. High Packaging Efficiency and Cost Saving

The COB packaging process is not much different from the SMD production process, but the packaging efficiency of COB packaging in dispensing, separation, light splitting and packaging is much higher. Compared with traditional SMD, it can save 5% of any and material costs.

2. Advantages of Low Thermal Resistance

The system thermal resistance structure of traditional SMD packaging is: chip-die bonding adhesive-solder joint-solder paste-copper foil-insulation layer-aluminum material. The system thermal resistance of the COB package is: chip-die-bonding glue-aluminum. The system thermal resistance of COB packaging is much lower than that of traditional SMD packaging, so the service life of LED lamps in COB packaging is greatly improved.

3. Light Quality Advantage

The traditional SMD package pastes multiple discrete devices on the PCB board to form the light source component of the LED application in the form of patches. This method has the problems of point light, glare and ghosting. The COB package is an integrated package and a surface light source, with a large viewing angle and easy adjustment, reducing the loss of light refraction.

The traditional SMD packaging method is to paste multiple different devices on the PCB board to form LED light source components. The light source made by this packaging process generally has the problems of electro-optic, ghosting and glare. The COB light source does not have the above problems. It is a surface light source with a large viewing angle and easy adjustment of the angle, which reduces the loss of light due to refraction.

4. Application Advantages

The application of COB light source is very convenient, and it can be directly applied to lamps without other processes. However, the traditional SMD package light source needs to be patched first, and then fixed on the PCB board by reflow soldering. It is not as convenient as COB in application.