3.2 Disadvantages of COB LED Screen

COB LED screens are getting a lot of attention, and for good reason, but they’re not without their issues. Like many new technologies, they still have some bugs to fix and details to polish before they can fully take over the market.

1. Low Packaging Yield and High Cost
   COB packaging has a relatively low first-pass yield, meaning defects occur more often during production. This results in higher manufacturing costs, especially at scale.
2. Lower Contrast
   COB screens generally have lower contrast compared to traditional SMD displays, which can affect overall image quality and visual experience.
3. Uneven Color Performance
   Because COB integrates chips closely, its color uniformity is not as good as SMD displays that use separate color chips. This may lead to uneven color display.
4. Wire Bonding Issues
   Current COB technology often uses wire bonding, which can cause problems like broken or weak connections. This increases manufacturing complexity and maintenance efforts.
5. Higher Manufacturing Costs
   Due to lower yields and more complex processes, COB screens cost more to produce than small-pitch SMD displays. For pixel pitches above 1.0mm, SMD remains the more cost-effective and mature option.
6. Not Suitable for Larger Pixel Pitches
   COB technology is mainly designed for ultra-small pixel pitches between 0.5mm and 1.0mm. For larger pixel pitches, SMD technology is still dominant because of its stability and easier maintenance.

4. Applications of COB LED Displays

COB LED displays are becoming popular in many fields thanks to their unique features like high brightness, durability, and excellent image quality.

Their versatility allows them to be used in a variety of settings where clear, reliable visual performance is needed.

• Indoor Advertising: Ideal for shopping malls, retail stores, and showrooms where bright, seamless images attract customers.
• Corporate Displays: Perfect for conference rooms, lobbies, and digital signage, offering sharp visuals with a sleek design.
• Entertainment and Events: Widely used in concerts, exhibitions, and trade shows due to their easy installation and high durability.
• Transportation Hubs: Useful in airports, train stations, and bus terminals for clear information displays that withstand heavy use.
• Public Spaces: Suitable for museums, galleries, and public information boards requiring reliable, high-quality screens.

The combination of durability, smooth visuals, and easy maintenance makes COB LED displays a smart choice across many industries.

5. LED Packaging Technologies: SMD, IMD, GOB, and COB

LED packaging technology is a crucial part of the LED industry chain. Essentially, it refers to the process of integrating LED chips with related components into a protective package, often called “LED encapsulation” in the industry.

From a technical perspective, different packaging methods can greatly affect LED performance. They directly influence key factors like light distribution, color quality, and overall lifespan, making packaging a vital part of LED design and development.

5.1 SMD

SMD (Surface Mounted Device) is one of the most established and widely used LED packaging methods. It involves mounting pre-packaged LED chips directly onto the PCB using SMT and reflow soldering, making it ideal for various pixel pitches.

(1) Advantages of SMD

SMD offers mature technology, low cost, and a complete supply chain. It also provides good heat dissipation and is easy to repair, which makes it a preferred choice for small-pitch LED displays.

(2) Disadvantages of SMD

For high-density needs like Mini LED, SMD becomes less efficient due to the large number of components and longer assembly time. It struggles to meet the compact demands of next-gen high-resolution displays.

5.2 IMD

IMD (Integrated Matrix Device) Packaging uses a 2×2 matrix design, combining four sets of RGB LED chips into a single unit.

It’s essentially an upgraded form of SMD, allowing for smaller pixel pitches, down to P0.4 in lab settings and P0.7 for mass production.

5.3 GOB

(1) Advantages

IMD allows for color binning and sorting, leading to better display consistency and visual quality.

It also offers a stronger push force than single SMD LEDs and supports higher production efficiency for mass manufacturing.

(2) Disadvantages

It may show grid patterns and moiré effects on the screen. Its moisture resistance is lower than COB, and costs remain higher in fine-pitch applications compared to COB.

GOB (Glue On Board) Packaging is a protective process applied to SMD modules by adding a transparent glue layer, like a strong armor. It covers both the PCB and LED units, offering enhanced durability against impact and moisture.

(1) Advantages

• The special transparent glue has high clarity and strong thermal conductivity, improving display quality and heat dissipation.
• GOB provides excellent protection from water, dust, static, salt spray, blue light, vibration, and oxidation—ideal for tough environments.

(2) Disadvantages

• It may face issues like screw stress release, limited heat dissipation, and repair difficulty.
• The adhesive strength of the glue can also be a concern in long-term use, especially under extreme conditions.

5.4 COB

COB (Chip on Board) packaging is an advanced LED packaging technology where LED chips are directly mounted onto the PCB and sealed with epoxy resin.

It includes two main types: flip-chip COB and wire-bonding COB.

(1) Advantages

This packaging method provides high protection against moisture, impact, dust, and static. It allows for smaller pixel pitches, supports wide viewing angles, and helps reduce moiré patterns, making it ideal for studios and film production. COB uses a surface light source, resulting in softer, eye-friendly visuals with high display uniformity. Its durability helps prevent common issues like dead pixels or visible chip defects, especially in fine-pitch and Mini LED displays.

(2) Disadvantages

The manufacturing process is complex, with low production yield and high technical difficulty for mass transfer. Maintenance is challenging, often requiring the module to be sent back to the factory for repairs. Compared to IMD, COB offers stronger protection and better viewing angles, but currently faces higher production barriers.

6. SMD vs IMD vs COB LED, Which is Better?

	COB: Chip on Board	SMD: Surface Mounted Devices	IMD: Integrated Mounted Devices	GOB: Glue on Board
Technical Approach	New process with high technical difficulty, eliminating traditional SMD packaging steps	Mature process	Developed further on SMD; SMD uses one package for a pixel, IMD uses one package for multiple pixels	Protection process where glue is applied to the SMD module to safeguard the device pins
Pitch	≥0.4mm	≥1.0mm	≥0.6mm	≥1.0mm
Impact Resistance	Excellent (>20kg)	Poor (<2kg)	Medium	Excellent
Reliability/ Stability	Excellent	Medium	Fair	Excellent
Maintenance Cost	High	Low	Low	Relatively high
Contrast Ratio	Relatively high	Medium	High	Medium
Heat Dissipation	Excellent	Medium	Medium	Poor
Consistency	Few companies have excellent consistency (most are improving)	Excellent	Excellent	Poor
Process Difficulty	High	Low	Medium	Low
Max Viewing Angle	170°~179°	170°	160°	170°

COB offers excellent impact resistance, reliability, heat dissipation, and wide viewing angles, but comes with high production difficulty and maintenance costs.

SMD is a mature, low-cost process with good consistency and medium heat dissipation, but it has poor impact resistance and a larger minimum pixel pitch.

IMD improves on SMD by packaging multiple pixels together, providing better consistency and impact resistance with moderate production complexity and cost.

GOB focuses on protecting SMD modules with glue, offering excellent impact resistance and reliability but suffers from poor heat dissipation and consistency, with relatively higher maintenance costs.

Each technology has strengths suited for different LED display needs, depending on durability, cost, and pixel density requirements.
 

7. Linsn COB VS. Conventional COB LED Screen

Now, let’s compare Linsn COB with conventional COB LED screens. This will highlight the key differences in performance and quality.

7.1 Black Level Uniformity Comparison

Many conventional COB displays show inconsistent black levels. Modules in the same batch often appear in different shades of black. Some are darker, some lighter, creating a patchy and uneven screen. This affects overall visual quality and uniformity. In extreme cases, 8 modules may display 8 different black tones. Such inconsistency is common in lower-grade COB solutions.

Linsn COB solves this problem with advanced manufacturing. All modules in the same batch maintain uniform black levels. The ink color is consistent, deep, and rich across the screen, ensuring a smooth, premium visual experience. Better uniformity also improves contrast and color accuracy. Linsn COB is ideal for high-end display applications.

7.2 Black Screen Power Consumption Comparison

Power efficiency matters, even when the screen is black. Many COB displays still consume noticeable power in black screen mode. Other COB brands use 24.9W per cabinet and 122.96W per square meter. This results in higher energy costs over time. Linsn COB features an energy-saving design. It only consumes 15.46W per cabinet and 76.35W per square meter.

Black Screen Power Consumption	Other COB Brands	Linsn COB	Result
	24.9W / Cabinet 122.96W / m²	15.46W / Cabinet 76.35W / m²	Linsn COB features an energy-saving design, reducing black screen power consumption by 37.9% compared to other COB brands.

That’s a 37.9% reduction in black screen power usage. Linsn COB helps reduce energy consumption without compromising performance.

Ideal for 24/7 applications, Linsn COB saves power and lowers operational costs. It is also efficient and eco-friendly.

7.3 White Screen Power Consumption Comparison

Power consumption under full brightness is a key performance indicator. At 540CD/m², most COB displays consume significant energy. Other COB brands use 63.8W per cabinet and 315.1W per square meter. This leads to higher electricity usage, especially in large installations.

Parameter	Other COB Brands	Linsn COB	Result
White Screen Power (per Cabinet)	63.8W	33.7W	Linsn COB reduces white screen power by 47.2% compared to others.
White Screen Power (per m²)	315.1W	166.42W	Improved energy efficiency at high brightness (540CD/m²).

Linsn COB adopts a power-saving design. It only consumes 33.7W per cabinet and 166.42W per square meter. That’s a 47.2% reduction in white screen power consumption. This makes Linsn COB more efficient and cost-effective for long-term use.

7.4 White Screen Surface Temperature Comparison

Surface temperature affects both user comfort and safety during close viewing. Many COB screens tend to generate high surface heat under full brightness. Other COB brands use standard designs. These often lead to higher surface temperatures and noticeable heat radiation.

White Screen After 1 Hour, Ambient Temperature @24℃	Other COB Manufacturers	Linsn COB	Result
Surface Temperature	49.1℃	36.6℃	Linsn COB energy-saving design reduces white screen surface temperature by 12.5℃ compared to other COB manufacturers.

Linsn COB uses “cool-touch” technology. The surface temperature stays close to normal body temperature, making it more comfortable for viewers. This temperature control helps reduce thermal discomfort during operation. It’s especially useful for indoor and interactive applications. Lower heat also contributes to overall system stability. Linsn COB delivers both efficiency and a better user experience without excessive heat.

7.5 Work Surface Temperature Comparison

At 24°C ambient temperature, other manufacturers’ COB LED screens reach 38.9°C during video playback. Linsn COB screens run cooler, with a surface temperature of 32.9°C under the same conditions. This means Linsn’s energy-saving design keeps the temperature about 6°C lower than others.

	Other manufacturers COB	Linsn COB	Result
Play video temperature @24℃	38.9℃	32.9℃	Linsn COB energy-saving screen design, the operating temperature is 6℃ lower than other manufacturers’ COB

7.6 Maximum Brightness Comparison

Most conventional COB screens on the market offer a peak white balance brightness of approximately 1000 cd/m². In contrast, Linsn’s advanced energy-saving COB technology reaches up to 1500 cd/m². This represents a significant 50% increase in brightness output.

With higher brightness, Linsn displays remain vivid and clear, even in high ambient light settings. Ideal for environments where strong visibility is essential.

7.7 Wide Viewing Angle Comparison

(1) Splicing Modular Comparison

Many COB displays from other manufacturers reflect more light due to glossier surfaces. Visible gaps between modules can disrupt the visual uniformity. These issues reduce the screen’s clarity, especially when viewed from side angles.

Linsn COB technology reduces surface glare effectively. Its seamless module integration creates a smooth and uniform display appearance. This leads to excellent visibility and image clarity from nearly any direction.

(2) Color Block Contrast

Unlike many other COB screens that suffer from color block seams, Linsn COB offers a much smoother, edge-free visual experience. The uneven color patches seen in some displays interrupt screen harmony.

Linsn solves this with precise calibration and seamless module alignment. From any viewing angle, colors on a Linsn COB screen remain uniform and accurate. This ensures a cleaner look and a better viewing experience overall.

7.8 Close-Up Surface Effect Comparison

White edges between LED panels are prominent in many COB displays from other manufacturers. Such visible borders tend to interrupt the viewing experience and degrade image quality.

In contrast, Linsn COB screens feature barely perceptible white edges between panels. This delicate design ensures smoother visual flow and a cleaner overall look.

7.9 Image Quality Comparison

Other manufacturers’ COB displays often appear with a grayish, hazy layer over the image. This reduces contrast and affects visual clarity. Linsn COB screens deliver clear, vibrant colors with high color accuracy. The result is a more lifelike and immersive viewing experience.

Black backgrounds on many other COB displays often look gray instead of true black. This reduces contrast and makes images look flat. Linsn COB features an ultra-black background that delivers deeper, richer blacks. This improves contrast and makes visuals sharper and more vibrant.

Many other COB displays often show dull colors and lose fine details. This results in a flat and less engaging visual experience. Linsn COB delivers vibrant colors with excellent brightness and contrast. Even the smallest details are visible on screen.

8. COB LED Display Troubleshooting and Maintenance Guide

COB (Chip on Board) LED displays are known for their seamless visuals, high durability, and fine pixel pitch. However, like all LED technologies, they may encounter performance issues over time that require effective diagnosis and repair.

8.1 COB LED Troubleshooting
 

(1) Dead Pixel

Causes: Dead pixels on COB LED displays can result from chip defects during manufacturing, such as bonding issues or internal damage. Environmental factors like high current, heat, moisture, or oxidation can also damage chips or connections, leading to dead spots.

Solutions: If within the warranty period, contact the manufacturer for repair or replacement. For minor defects, visual compensation via software calibration may help, but large-scale issues require disassembly and professional chip/module replacement.

(2) Uneven Brightness

Causes: Uneven brightness is often caused by inconsistent drive currents or performance drift in driver ICs over time. Poor chip binning during production—using LEDs of different brightness levels—can also lead to visible brightness differences.

Solutions: Use a professional brightness calibration system to measure and adjust each area’s brightness in the control software. In severe cases, replace affected modules with ones that offer better brightness uniformity.

(3) Color Distortion or Flickering (Flower Screen Issue)

Causes: Color distortion or flickering—also known as a “flower screen”—often stems from signal transmission failures, poor cable connections, aging wiring, or electromagnetic interference. Software mismatches or control system errors can also contribute.

Solutions: Check all signal connections and cables for tight contact or damage. Replace faulty lines, shield against interference, and ensure the software is correctly configured and up to date. If problems persist, consult the manufacturer for system diagnostics or firmware updates.

8.2 Maintenance Tips for COB LED Displays
 

Environment: Keep displays in dry, temperature-controlled, and dust-free conditions to avoid chip degradation.

Cleaning: Gently clean the surface with soft cloths and alcohol-based solutions. Avoid water and hard tools.

Software Updates: Periodically update firmware and recalibrate the display to maintain performance.

Regular Checks: Conduct visual inspections and light tests monthly to detect early faults and ensure brightness consistency.

9. FAQs

(1) Can brightness inconsistency be fixed?

Yes. Use calibration software to adjust brightness across regions or replace modules with better brightness uniformity.

(2) Is COB LED good for outdoor use?

COB has high protection but is mainly used indoors. For outdoor use, weatherproof SMD models are usually better.

(3) Do COB displays support 4K or 8K resolution?

Absolutely. Thanks to ultra-fine pitch capability, COB is ideal for 4K/8K high-resolution indoor display walls.

(4) How to choose between COB, SMD, and IMD?

Choose COB for high-end, fine-pitch, high-protection needs; SMD for general-purpose and outdoor use; IMD for a balance of both.

10. Conclusion
 

When clarity, stability, and reliability matter, a COB LED display can be a smart investment for everything from retail spaces to control rooms.

Want to upgrade with confidence? Explore LinsnLED’s LED display solutions today, and if you have any questions, feel free to contact us anytime!