COB Display

COB Mini/Micro LED display technology development in 2021

With the rapid development of mass transfer technology, coating technology, and full flip-chip packaging technology, COB Mini / Micro LED Display has achieved new breakthroughs in 2021, and some mature products have overcome the problem of color inconsistency.

The LED displays integrated through COB flip-chip technology can have higher contrast, deeper color saturation, and smaller pixel pitch.

Features of COB Mini/Micro LED Display

Mini / Micro COB LED displays mainly consist of four features: The first is the ultra small pixel pitch. The second is full flip-chip technology. The third is common cathode technology, and the fourth is COB technology.

COB & Flip-chip

COB stands for chip-on-board packaging technology that multiple LED chips are directly mounted on a PCB substrate. It directly conducts heat to the PCB.

COB can use two types of structures: wire bonding or flip-chip.

For the conventional wire bonding structure, when the chip is miniaturized, the light-shielding rate and thermal resistance of the electrode of the chip by the gold wire increase. It affects light efficiency and lifespan. In addition, the distance between the chip and the gold wire also limits the micro fine-pitch design.

On the contrary, the flip-chip structure has no shield on the light-emitting surface, and the electrode is flat on the pad, which has a better heat dissipation effect, higher light efficiency, and longer lifetime. This applies to ultra-fine pitch designs.

Both Sony’s crystal screen and Samsung’s The Wall adopt flip-chip COB packaging technology.

Common Cathode Driving Technology

“Common cathode” technology refers to a common cathode power driving method. This type of LED display uses separate voltages for R, G, and B lamps, and accurately distributes the voltage and current to the red, green, and blue lamps.

The current flows through the lamp pin and then to the negative terminal of the IC. Therefore, the forward voltage is reduced, and the internal resistance of conduction becomes smaller.

For a long time, temperature and power consumption are the key factors affecting the life of LED displays.

By adopting precise power control technology, common cathode LED displays can reduce power consumption and heat generation. Therefore, the stability and reliability of the entire display system can be improved, and the service life of the system can be greatly extended.

COB displays have the following advantages:

Ultra-high contrast

The surface of the flip-chip COB display is dark. The black area ratio of a single-pixel of the display screen is as high as 99%, the contrast ratio is as high as 2,000,000:1, and it is less affected by ambient light.

High brightness & Good color consistency

The brightness range is >600CD/㎡, up to 1300cd/㎡. The thickness of the full flip chip is extremely consistent, close to the surface light source effect

Wide viewing angle and color gamut

The viewing angle is up to 170°, and the NTS color gamut is ≥115% NTSC. The display has rich colors, bright visual effects, and ultimate visual experience.

High gray scale and refresh rate

The gray level of the product is 22 Bits, any image details will not be lost, and the light and dark changes are more delicate; the refresh rate is as high as 3840 Hz

Super stable

Ultra-high reliability and stability, the pixel failure rate is less than 10PPM. Compared with traditional SMD technology, the failure rate is reduced by an order of magnitude

Waterproof on the front

Waterproof and wear-resistant, can be scrubbed directly, easy to clean


Anti-collision, no LED falling, anti-collision test value> 10KG

Dust-proof, Moisture-proof and anti-static

COB packaging technology is the only technology that can directly implement touch operations on the LED screen.

Low power consumption

The common cathode solution has the advantages of fast heat dissipation, low power consumption, and long life.

Compared with the traditional SMD technology, the screen temperature is lower than 45°, and the peak power consumption is lower than 400w/㎡

COB displays application areas:

Command center, dispatch center, monitoring center, enterprise exhibition hall, data center, exhibition hall, brand chain store, commercial center, lecture hall, studio center, theater/home theater, conference center, audio-visual center, automobile dealer shop, etc.

Application of Mini LED in the latest 5G+8K technology

The resolution of 8K is 4 times 4K and 16 times 1080p. The 8K contents require ultra-large broadband signal transmission, and the required technology is 5G. In other words, 5G provides a high-speed channel for 8K video real-time transmission, and a display with 8K resolution provides the content presentation platform for 5G ultra-high-speed bandwidth.

Why use Mini LED for 8K display?

LCD: It is the most mature technology and has the lowest cost. However, the display effects such as brightness can no longer be compared with the LED, and there is a physical limit in size.

OLED: Once known as a new trend in the display field, the visual effect is outstanding. However, due to the high cost, it is currently mostly used in electronic products with small size panels.

Mini LED: Although the current cost is relatively high, it can not only achieve super large size and super high resolution, but also has obvious advantages in wide color gamut and HDR display. And its cost will down much every year.

So Mini LED has become one of the most suitable ways to undertake 8K+5G.

Mini LED has two application directions: backlight and direct display.

Mini LED backlight

The LED is used as the backlight layer of the LCD, and the screen can be dynamically dimmed through fine partitions to improve the HDR performance of the LCD display, but it is actually still LCD.

Mini LED direct display

Mini LED direct display means that the LED chip directly emits light. The RGB three-color chip forms a pixel, which can not only achieve pixel-level light control, but also is far better than LCD and OLED in terms of power consumption, brightness, color saturation, life span, and response speed.

Among them, the Full-flip COB Mini LED displays are superior to other direct display products in terms of visual effect and surface protection.

Not only that, the smaller the LED chip, the more flexible it can meet the display requirements for 8K resolution. The full flip-chip Mini COB technology can make the chip and pixel pitch smaller. It is the solution closest to the Micro LED display, and at present, it is also an excellent display platform for 5G+8K.

At present, the application of 5G+8K with full-flip Mini COB has begun to enter the fields of studio entertainment, command center, security monitoring, etc. It can ensure that the viewing is not grainy, the video is smoother, and the visual enjoyment is more comfortable, realizing a true 5G +8K.


3CINNODisplay is a leading custom-solution-based led display manufacturer located in Shenzhen, the developing and manufacturing center of high-end led displays.

We devoted to using new technology to rich the display lines and giving more value to our clients to help them win the market. 3CINNODisplay is finding good reputation COB display modules and making finished COB display products for our customers’ bespoke projects.

If you are interested in getting a high performance COB display for your customer, please don’t hesitate to fill out the form to get our consultation.

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