Formal VS Full Flip COB: Who will dominate the future LED display market?

With the rapid development of small-pitch LED technology, COB (Chip on Board) technology, as one of the best, has received widespread attention and application worldwide in recent years. In the booming P1.0 and below micro-pitch display market, COB technology stands out from the crowd and becomes the core of the core. Among them, flip-chip COB stands out with its unique chip-level gap realization capability, leading the new technology trend. It not only opens up a broad imagination space, but also attracts the attention and pursuit of the industry for its excellent performance!

The development of micro-pitch LED display has become a major mainstream trend in the display field. In recent years, COB display technology has ushered in a period of rapid development, attracting many manufacturers to join in. What is COB? What is formal COB? What is full flip COB? Formal VS flip COB, which one is more popular with users?

Introduction to COB technology

COB (Chip on Board) technology, that is, the technology of directly mounting chips on circuit boards, originated in the 1960s. It simplifies the packaging structure and improves the stability of the product by directly soldering the exposed chip or electronic components on the circuit board and covering it with special resin. This technology not only significantly improves the brightness and contrast of the LED display, but also greatly extends its service life.

1. COB classification

COB display screens can also be distinguished according to different packaging technologies, mainly including positive COB and full flip COB:

⑴ Positive COB:

Positive COB refers to connecting the positive and negative electrodes of the LED chip to the pads on the PCB board through gold wire ball welding and other methods to achieve electrical connection. Positive COB technology has the advantages of mature process and low cost, but it has disadvantages such as easy breakage of welding wires and general heat dissipation performance. With the continuous reduction of dot pitch, positive COB technology has reached its performance limit in some high-end application scenarios.

⑵ Full flip COB:

Full flip COB refers to directly facing the light-emitting surface of the LED chip to the audience, and connecting it to the pads on the PCB board through advanced processes such as micro-bumps. This packaging method does not require welding wires, reduces physical connection points, and thus improves the stability and reliability of the product. At the same time, the full flip-chip COB technology also has the advantages of better heat dissipation performance, higher luminous efficiency and lower power consumption. With the continuous advancement of technology, the full flip-chip COB technology has become the mainstream trend in the micro-pitch LED display market.

2. Detailed explanation of the COB display packaging process:

⑴ Crystal expansion: First, carefully place the precision LED chip on the crystal expansion ring, and then place the crystal expansion ring securely on the working surface of the back glue machine that has been pre-coated with a silver paste layer to perform the crystal expansion operation, laying a solid foundation for subsequent steps.

⑵ Back glue treatment: Then, transfer the crystal expansion ring that has completed the crystal expansion to the back glue machine, and use the glue dispenser to accurately apply an appropriate amount of silver paste on the PCB printed circuit board to ensure that the paste is firm and uniform.

⑶ Fine crystal piercing: Then, place the crystal expansion ring with silver paste in the crystal piercing frame. With the assistance of a microscope, the operator carefully pierces the LED chip into the designated position of the PCB printed circuit board with a crystal piercing pen.

⑷ Baking and curing: Place the PCB printed circuit board with completed crystal embroidery into a thermal cycle oven and leave it at a constant temperature for a period of time until the silver paste is completely cured. Take it out after ensuring the connection is stable.

⑸ Wafer placement: Next, use a glue dispenser to accurately apply red glue or black glue on the wafer position of the PCB printed circuit board, and then use anti-static equipment to accurately place the wafer on the glue point.

⑹ Lamination protection: Use a professional lamination device to closely fit the pre-prepared film material to the surface of the display screen to provide it with comprehensive protection and performance enhancement.

⑺ Re-curing: Place the PCB printed circuit board with glue sealed into the thermal cycle oven again, set the constant temperature and stand time according to specific needs to ensure that the glue is completely cured.

⑻ Final inspection: Finally, a comprehensive inspection process is carried out to strictly control the quality of the COB display screen to ensure that its various performance indicators meet high standards.

In the entire packaging process, each step requires precise control and strict inspection to ensure the quality of the final product. At the same time, with the continuous improvement and perfection of production technology, the packaging efficiency and product quality of COB display screens are also constantly improving.

Formal VS Full Flip

In the packaging methods of COB technology, formal and full flip are the two main packaging forms. Formal COB technology is to connect the positive and negative poles of the LED chip to the circuit board through gold wire ball welding and other methods, while full flip COB is to directly face the light-emitting surface of the LED chip to the audience and connect it to the circuit board through advanced processes such as micro-bumps.

1. Significant advantages of formal COB:

⑴ Excellent brightness: The formal COB packaging technology cleverly attaches the LED chip directly to the PCB board, which significantly improves the brightness of the display screen and presents a clearer and more vivid visual effect.

⑵ High contrast performance: Through the formal COB packaging process, the contrast of the LED display is effectively enhanced, the black is deeper, the white is purer, and the colors are fuller and brighter, bringing a shocking visual experience to the audience.

⑶ Durable: With its excellent heat dissipation performance and stability, the formal COB packaging process significantly extends the service life of the LED display, reduces maintenance costs and replacement frequency, and brings long-term economic benefits to users.

⑷ Powerful heat dissipation capacity: The formal COB product directly encapsulates the LED light-emitting chip (wafer) on the PCB board, and uses the copper foil on the PCB board to quickly conduct heat to ensure that the wick maintains low temperature operation. At the same time, strict process requirements and immersion gold treatment further reduce light attenuation, greatly extending the life of the display.

⑸ Wear-resistant and easy to clean: The surface of the light point of the formal COB display is flat and smooth, hard and wear-resistant, and can remain intact even if it is hit. If a bad point occurs, it can be repaired point by point, which is convenient and quick. In addition, the mask-free design makes cleaning easier, and dust can be easily removed with water or cloth.

⑹ All-weather application: The formal COB display has undergone triple protection treatment and has excellent waterproof, moisture-proof, anti-corrosion, dust-proof, anti-static, anti-oxidation and anti-ultraviolet capabilities, meeting all-weather working conditions. Even in a temperature difference environment of -20 degrees to 60 degrees, it can still maintain normal and stable operation.

2. Advantages of full flip-chip COB

⑴ Ultra-high reliability: The thickness of the packaging layer of the full flip-chip COB is further reduced, which completely solves the problem of color lines and bright and dark lines between the regular COB modules. This makes the black field of the full flip-chip COB darker, brighter, and higher in contrast, supporting HDR digital image technology, presenting a fine and perfect effect of static and high dynamic picture quality.

⑵ Simplified process, better display: As an upgraded product of the regular COB, the full flip-chip COB further improves reliability and simplifies the production process while maintaining the advantages of the regular COB's ultra-small dot pitch, high reliability, and non-glare surface light source. This makes the display effect of the full flip-chip COB better, the near-screen experience is perfect, and the chip-level spacing in the true sense is realized.

⑶ Large size, wide field of view: The full flip-chip COB supports unlimited size free splicing of 2K/4K/8K resolution, which is suitable for large scene display. It has good viewing angle and side display uniformity, no color cast at a wide viewing angle, and can achieve a viewing effect of 170 degrees, bringing a more shocking visual experience to the audience.

⑷Ultra-high density, smaller dot pitch: The full flip-chip COB is a true chip-level package that does not require wire bonding. Its physical space size is determined only by the size of the light-emitting chip. This enables full flip-chip COB to break through the dot pitch limit of the front-mounted chip and become the first choice for products with a dot pitch of less than 1.0.

⑸Energy-saving and comfortable, good near-screen experience: The full flip-chip light-emitting chip reduces power consumption by 45% under the same brightness conditions. At the same time, the unique heat dissipation technology makes the surface temperature of the screen body 10°C lower than that of the conventional front-mounted chip LED display at the same brightness, which is more suitable for the application scenario of the near-screen experience, bringing a more comfortable and energy-saving viewing experience to the audience.

Formal VS full flip: Who is more popular with users?

In the competition between formal and full flip COB, full flip COB has gradually won the favor of the market with its ultra-high reliability, simplified process, better display effect and smaller dot pitch. Especially in the high-end display market, such as command centers, monitoring centers, data centers and other places, full flip COB has become the first choice due to its excellent performance and stability.

However, the full-mount COB is not without a market. In scenarios with high brightness requirements and limited cost budgets, full-mount COB still has a greater competitive advantage. In addition, with the continuous advancement of technology and the reduction of costs, full-mount COB is also expected to develop in the direction of smaller dot pitch and higher reliability.

The development prospects of COB display

The development prospects of COB display in the future are very broad. With the continuous advancement of technology and the continuous expansion of the market, COB display will gradually replace traditional SMD display and become the mainstream of the micro-pitch display market. At the same time, full flip COB, as an upgraded product of full-mount COB, will occupy a larger share in the high-end display market with its excellent performance and stability.

In addition, with the continuous development of technologies such as 5G, Internet of Things, and artificial intelligence, COB display will also be deeply integrated with these technologies to achieve more intelligent and personalized display effects. For example, remote monitoring and maintenance can be achieved through Internet of Things technology; intelligent adjustment and optimization of display effects can be achieved through artificial intelligence technology. These will bring new opportunities and challenges to the development of COB display.

In summary, both the front-mounted and full-flip COB technologies are constantly driving the development and progress of the LED display industry. As the leader among them, full-flip COB has become a star product in the future LED display market with its excellent performance and broad application prospects.

Shenzhen Shinerave is a leading domestic supplier of LED displays.