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COB Vs. IMD LED Display:What is Difference?

by | Mar 25, 2024 | Blogs | 0 comments

In the field of small-pitch LED screens, Mini LED packaging mainly includes two solutions: COB (Chip on Board) technology and IMD (Integrated Mounted Devices) integrated packaging technology. But do you know their differences? Today DOITVISION will introduce their differences.

What is COB LED Packaging?

COB LED Packaging

Imagine a scenario where tiny LED chips are directly placed and adhered onto a circuit board. That’s essentially what COB LED packaging is all about. COB is a multi-lamp bead integrated bracket-less packaging technology that directly packages the LED light-emitting chip on the PCB board, eliminating the cumbersome surface mounting process. Without the soldering pins of the bracket, each pixel’s LED chip and welding wire are tightly encapsulated in the epoxy resin colloid without any exposed elements.

You can lean More Flip-Chip COB LED Display

COB LED Packaging Features:

  • High Uniformity: Because the LEDs are closely packed, the light output is extremely uniform, providing a consistent brightness and color across the display.
  • Enhanced Durability: With fewer components and a solid board base, COB LEDs are quite durable and resistant to issues like vibration and impact.
  • Better Heat Dissipation: The structure of COB LEDs allows for efficient heat distribution, ensuring the LEDs stay cooler and thus last longer.
  • Compact Size: The integration of multiple LEDs into a single module allows for a more compact and streamlined design.
  • Excellent Color Rendering: COB LEDs often have superior color rendering, making colors appear vibrant and true-to-life.

Advantages of COB LED Display 

COB LED display screen can easily achieve pixel pitch below 1.0mm;

  • Stronger protection capability: the device is not exposed, and the product will not lose lights due to shaking or excessive force during transportation, installation, and disassembly. The collision resistance and load-bearing capacity are 5 times that of the SMD packaging structure;
  • Ultra-thin, lighter Cabinet: It is easier to install, disassemble and transport;
  • Better outdoor environment endurance: It can normally display in water mist, cold and humidity, thunderstorms, oxidative corrosion, etc environment.
  • Good heat dissipation capacity: The heat is dissipated directly through the PCB board, the thermal resistance value is small, and the heat does not accumulate, therefore, the screen life is longer;
  • Better light perception: the surface light source emits light, effectively suppresses moiré patterns, and does not hurt the eyes when viewed at close range.

You can learn more Why Choose COB LED Displays

What is IMD LED packaging?

IMD LED display

Now, let’s shift our focus to IMD LED packaging. Imagine a technology that integrates LEDs, drivers, and ICs (Integrated Circuits) all into a single module. This is what IMD offers. MD (Integrated Matrix Devices) matrix integrated packaging solution (also known as “N-in-1” or “all-in-one”) integrates two, four or six groups of RGB lamp beads into a small unit. Currently, The typical method is in the form of 2*2, that is, 4 in 1, integrating and packaging 12 RGB three-color LED chips.

IMD LED Packaging Features:

  • Flexibility: The LEDs can be mounted on flexible substrates, opening up a myriad of design possibilities.
  • Integrated Design: By combining LEDs, drivers, and ICs into a single module, IMD packaging simplifies the assembly process and reduces the overall size of the LED display.
  • High Resolution: Thanks to the ability to place LEDs very closely, IMD technology can achieve high-resolution displays with excellent clarity and detail.
  • Energy Efficiency: IMD packaging is designed to be energy-efficient, reducing power consumption without compromising on brightness or quality.
  • Durability: Although lightweight, IMD LED displays are durable and resistant to environmental factors like moisture and dust.

Comparison between COB LED Packaging and IMD Packaging

DOIT VISION COB LED Display 02
DOIT VISION COB LED Display 02

When choosing between COB and IMD LED packaging, it is really based on what your specific needs are. Here’s a comparative tip:

Display effect:

Ink color consistency

The color difference of COB LED modules is more obvious, and early IMDs will also have large-angle pitting, but these have been well resolved at present. In addition, the cost of COB screen is much higher than that of N-in-one package IMD devices. 

Color consistency

Because the optical difference between COB is large, and the smaller the LED module, the more obvious it is. However, COB packaging is a mixed chip material, which cannot be tested and sorted. The consistency of color difference cannot be guaranteed. Point-by-point correction can only meet the front face. The color difference is larger at left and right viewing angles. 

IMD can import full test sorting to eliminate defects to the greatest extent, and the brightness ratio can be 1:1.5~1:1.3.

Yield (PCB yield + process yield + rework efficiency/yield)

PCB yield: For COB LED display below P0.7, the smaller the pad spacing of the carrier board, the more difficult the multilayer board process is, and the lower the yield; IMD, P0.5-P0.9, It can be easier at 2-layer boards, and the difficulty of PCB board manufacturing process is greatly reduced.

Packaging process yield: For the COB LED display, the denser the lamp beads are, the lower the pass rate is. To ensure that there are no dead pixels before packaging, laser repair equipment must be used to improve the total yield, and the repair efficiency is low; IMD, the process is mature, and defective products can be directly Eliminated during testing

Reliability

In terms of anti-collision capability, the IMD (P0.9) welding thrust value reaches 2-3kg, which can meet the needs of the rental market.

Maintenance difficulty: The failure rate of IMD (P0.9) and COB-P0.9 is < 10 ppm. However, IMD can be repaired on site and the corresponding bad pixels can be directly replaced with good products. The maintenance cost is low. However, COB LED display is difficult to repair and needs to be replaced the module. 

Comprehensive cost:

Color consistency cost

COB (resolution 16*16=256), theoretical concentration =0.98^256=0.56%. Far lower than IMD 92.13%.

Because the more chips there are in COB integrated packaging, the higher the requirements for the chip segment. A narrower distribution of chip feed must be used to ensure better consistency. The correction technology can only ensure the consistency of the front, and there will still be chromatic aberration at large angles. Therefore, the color consistency cost of COB LED display is higher than that of IMD LED display.

Manufacturing cost

Taking the P0.9 LED display as an example, the manufacturing cost ratio is about 25-30% for COB and about 10-15% for IMD.

Comparing the comprehensive display effect and cost, for the Below P0.9 LED display, IMD LED display has comprehensive advantages in technology, cost, and rapid industrialization; 

For P0.4-P0.7 LED display, if LED display manufacturers can improve the yield rate, and reduce production cost, then the COB LED display will still have great advantages.

Here’s a quick comparison of SMD/IMD, MiP, and COB technologies:

Feature/TechnologySMD/IMDMiP (Micro LED Integration into Panel)COB (Chip on Board)
Dependency on Industry EcosystemMostly relies on existing industrial ecosystem; minimal additional R&D and fixed asset investments required.Utilizes smaller Micro LED chips for potential material cost savings; can use existing assembly lines but requires higher precision equipment for encapsulation or module production.Requires significant investments in high-precision manufacturing and testing equipment, including die bonders, printers, and AOI (Automated Optical Inspection) equipment.
Initial InvestmentLow; leverages existing infrastructure with little need for new investments.Lower than COB; necessitates additional investment in higher precision production and testing equipment, but can utilize existing SMD/IMD lines.High; demands substantial investment in specialized fixed assets for precision manufacturing and testing.
Cost Curve Relation to Industry ScaleAverage cost curve relatively stable; little to no change with industry scale due to low dependency on additional investments.Average cost decreases with scale, but at a slower rate than COB; initial investments less than COB but higher than SMD/IMD.Average cost significantly decreases with increased scale; requires large sales volume to amortize the high fixed costs, offering a clear cost advantage at scale beyond a certain point (q*).
Cost Advantage at ScaleLimited; cost advantages do not significantly improve as the industry scale increases.Moderate; benefits from scale but to a lesser extent compared to COB, due to the initial investment in precision equipment.Significant; achieves clear cost advantages at a larger scale, necessitating a substantial market size to offset the initial high fixed costs.

More:

MIP Vs. COB Small Pixel Pitch LED Display: Which is Better?

However, as more top LED display manufacturers like DOITVISION join COB LED display research and development. COB LED displays have not only gradually broken through technical limitations, become more mature and stable, but also reduced production costs, thus further broadening the prospects of COB LED displays.

cob led displays
doitvision cob led displays

Current Market Size of COB Panels:

  • The COB LED panel market was valued at $408 million in 2022, growing to $511 million in 2023, as per TrendForce’s analysis.
  • With an average price of $3000 per square meter in 2022 and $2000 in 2023, the sales area for COB panels was about 13,600 and 25,550 square meters per month, respectively.

Potential Market Size Considering COB LED Technology:

  • The entire LED display market, valued at $7.56 billion and representing about 5 million square meters per year (2023 estimate), is seen as the potential target market for COB technology.
  • However, this includes market segments not suitable for COB technology, like outdoor LED displays and indoor LED screens with pixel pitches above P2.5, suggesting that the actual replaceable market is significantly smaller.

Expansion Potential with Virtual Pixel Technology:

  • The introduction of LED virtual pixel technology, which significantly reduces costs, can potentially make COB LED panels more competitive and increase their market appeal in the consumer sector.
  • If all display needs were converted to 4K screens, the market size would be equivalent to about 110,000 screens, with a much smaller segment for fine-pitch displays.
  • With an assumption that a small percentage of the monitor and TV markets could switch to LED direct displays, the growth potential for COB panels in consumer markets is substantial, potentially expanding the market size several times over the current demand.

In Conclusion

Both COB and IMD LED packaging technologies have their unique advantages. As you consider investing in fine-pitch LED display, please choose them based on your project requirements. 

With the advancement of technology, COB LED displays are becoming more and more popular, and you can look for a reliable partner, such as DOITVISION. Our COB LED display has obvious advantages in terms of durability, uniform light, and flexible design. When you choose a DOITVISION COB LED display, you are investing in reliable and cutting-edge display technology.

About the Author

Kris Liang

Kris Liang

Founder/LED display expert

Kiris Liang is the founder of Doitvision. 12 + years in LED visual industry. Full passion of LED, product designer & chief salesman. Looking for teammate of technical/ marketing / sales.

Connecting people relative with LED displays.

Email: kris@doitvision.net