With the rapid advancement of fine-pitch LED technology,COB technology has emerged as a frontrunner. It has gained widespread attention and application globally, especially in the booming micro-pitch market below P1.0.
Within this space, COB technology is leading the charge as a core technology. Among these, flip-chip COB has gained prominence due to its exceptional chip-level gap capabilities. It has redefined the industry, pushing boundaries and attracting significant attention for its outstanding performance.
Micro-pitch LED technology has become a dominant trend in the display industry. In recent years, COB technology has experienced explosive growth, attracting numerous manufacturers. But what is COB technology? What is traditional COB, and what is flip-chip COB? And which one is more popular? Let’s explore.
Introduction to COB Technology
COB (Chip on Board) technology refers to the method of directly mounting LED chips or electronic components onto a circuit board. This technique originated in the 1960s and simplifies the packaging structure, while enhancing the product’s stability. By mounting the bare chip onto the board and covering it with special resin, COB technology improves brightness, contrast, and longevity.
Key Features of COB Technology:
- – Direct mounting of chips to the PCB.
- – Improved brightness and contrast.
- – Increased lifespan and product stability.
Types of COB: Traditional vs. Flip-Chip
COB technology can be divided into two main types, including: traditional COB and flip-chip COB.
Traditional COB:
Traditional COB involves connecting the positive and negative terminals of an LED chip to the PCB using gold wire balls or other methods. This technique is well-established, with a relatively low cost and mature manufacturing process. However, as pixel pitch continues to shrink, traditional COB technology has reached its performance limits in high-end applications.
Key Features of Traditional COB:
- – Reliable and mature manufacturing process.
- – Lower cost compared to flip-chip.
- – Vulnerable to wire bonding issues.
- – Average heat dissipation performance.
Flip-Chip COB:
In contrast, flip-chip COB technology involves flipping the LED chip so that its emitting surface faces the viewer. The chip is directly bonded to the PCB through advanced methods like micro bumps, eliminating the need for wire bonding. Therefore, it can improve LED display stability, better heat dissipation, higher luminous efficiency, and lower power consumption. With continuous advancements in technology, flip-chip COB has emerged as the dominant trend in the micro-pitch LED display market.
Key Features of Flip-Chip COB:
- – Chip faces the viewer directly for optimal light emission.
- – No need for wire bonding, increasing stability.
- – Superior heat dissipation and lower power consumption.
- – Higher luminous efficiency and better contrast.
COB LED Display Manufacturing Process
The COB display manufacturing process involves several critical steps, each requiring precision to ensure high-quality results.
Key Steps in the Manufacturing Process:
1. Crystal Expansion:
The LED chip is carefully placed on a crystal expansion ring. This ring is then placed on the back of a silver paste-coated machine, setting up the foundation for the next steps.
2. Back Glue Application:
The expansion ring is transferred to a glue dispensing machine. A precise amount of silver paste is applied to the PCB to ensure a secure and uniform attachment.
3. Chip Mounting:
The chip is delicately placed on the PCB under a microscope using a needle tool. It can be perfect alignment with the pre-applied silver paste.
4. Curing:
The PCB is then placed in a heat-cycling oven, where it is left at a constant temperature until the silver paste solidifies.
5. Wafer Placement:
After curing, red or black glue is applied at specific locations on the PCB, where the wafer is carefully placed.
6. Film Protection:
A protective film is applied to the display surface to provide extra durability and enhanced performance.
7. Curing Again:
The PCB with the film is placed back into the heat-cycling oven to complete the curing process.
8. Final Testing:
The final step involves comprehensive quality testing, ensuring the display meets the required performance standards.
Comparing Traditional vs. Flip-Chip COB
Traditional COB Advantages:
1. Excellent Brightness: Traditional COB improves brightness by directly attaching the LED chip to the PCB, resulting in a clearer, more vivid display.
2. High Contrast: The packaging enhances the contrast, with deeper blacks and purer whites, producing more vibrant colors.
3. Durability: Thanks to its superior heat dissipation and stability, traditional COB displays last longer, reducing maintenance and replacement costs.
4. Strong Heat Dissipation: By placing the LED chip directly on the PCB, heat is effectively conducted through the copper foil. It can keep the chip at a low operating temperature and extend the display’s lifespan.
5. Scratch Resistance & Easy to Clean: The smooth surface of traditional COB displays is highly resistant to scratches, and cleaning is easy with just water or a cloth.
6. All-Weather Performance: With triple protection for water resistance, anti-corrosion, and anti-UV capabilities, traditional COB displays work efficiently in extreme temperature ranges.
Flip-Chip COB Advantages:
1. Ultra-High Reliability: Flip-chip COB offers a thinner packaging layer, resolving issues like color lines and brightness discrepancies seen in traditional COB. Therefore,Flip-chip COB has deeper blacks, brighter whites, and higher contrast. It supports HDR technology for clearer, more dynamic visuals.
2. Simplified Manufacturing, Better Display: Building on the advantages of traditional COB, flip-chip COB eliminates wire bonding and further simplifies the manufacturing process. Therefore, It can enhance reliability and bring a better visual experience.
3. Large Sizes & Wide View Angles: Flip-chip COB supports 2K, 4K, and 8K resolution. It offers seamless, large-scale displays, perfect for high-end applications. In addition, It provides consistent color and brightness across wide viewing angles, up to 170 degrees.
4. Higher Pixel Density & Smaller Pixel Pitch: As a true chip-level packaging, flip-chip COB has no physical connection limitations, allowing for a smaller pixel pitch. Therefore, it is the preferred choice for P1.0 or lower display.
5. Energy-Efficient and Comfortable Viewing: Flip-chip COB displays consume 45% less power for the same brightness compared to traditional COB. Advanced heat dissipation technology also ensures that the surface temperature remains lower by 10°C. Therefore, it is ideal for close-viewing environments.
Which Technology is More Popular Among Users?
Between traditional and flip-chip COB, flip-chip COB is gaining market dominance. Its ultra-high reliability, superior display quality, and smaller pixel pitch make it the preferred choice in high-end display markets.
- Command centers
- Monitoring rooms
- Data centers.
Due to better contrast, reliability, and resolution, flip-chip COB have driven its increasing popularity.
However, traditional COB still has a strong position in the market. For demand high brightness and have limited budgets, It remains an excellent choice. As the technology continues to evolve, traditional COB may also see improvements in reliability and pixel pitch, allowing it to remain competitive.
The Future of COB Displays
The future of COB displays looks promising. With ongoing technological advancements and a growing market, COB is expected to replace traditional SMD displays and become the mainstream choice for micro-pitch LED displays. Flip-chip COB, as an upgraded version of traditional COB, will continue to capture a larger share of the high-end display market due to its superior performance and stability.
Furthermore, with the rise of 5G, the Internet of Things (IoT), and Artificial Intelligence (AI), COB displays will integrate more closely with these technologies. This will enable intelligent and personalized display effects, such as remote monitoring and maintenance through IoT or AI-driven optimizations. These advancements will create new opportunities and challenges for COB technology.
Challenges and Opportunities
While the future of COB displays is full of promise, there are still challenges to overcome. One of the main challenges is the high cost of production, particularly for flip-chip COB displays. However, as the technology matures and production processes become more efficient, costs are expected to decrease. We believe that COB displays have a wider range of applications.
Additionally, as more industries adopt COB technology, the demand for custom solutions will rise. LED display Manufacturers will need to develop flexible and scalable COB systems to meet the specific needs of different applications.
The Role of Sustainability
Sustainability is another driving force behind the adoption of COB displays. As energy efficiency becomes a higher priority across all industries, COB technology offers significant advantages. Due to its low power consumption and better heat dissipation, COB displays are more energy-efficient than traditional display technologies. This not only reduces operational costs but also contributes to the growing demand for environmentally friendly solutions.
In addition, COB displays’ longer lifespan means fewer replacements, which contributes to less electronic waste.
Conclusion
Both traditional and flip-chip COB technologies are pushing the LED display industry forward. However, flip-chip COB will be the future of LED display technology. Its remarkable performance, coupled with its vast application potential, makes it the star product of the LED display market.
As technology continues to evolve, both types of COB will continue to play crucial roles. Traditional COB will thrive in budget-sensitive applications, while flip-chip COB will dominate high-end markets, setting new standards for LED displays worldwide.
