COB LED technology is an emerging LED packaging technology, different from the traditional SMD LED package, it is to integrate light-emitting chips in the PCB board, rather than soldering to the PCB one by one. COB has the advantages of high reliability, low cost, small pitch and wear-resistant and anti-collision, which effectively improves the luminous light color of LED display, reduces risk and reduces costs.
Table of Contents
What are the components of LED display
1. LED unit board
It is one of the core components of LED display, and the quality of the unit board directly affects the effect of the display display. The unit board is composed of LED module, driver chip and PCB.
2. Control card
Using a low-cost strip screen control card, which can control a 256×16 dot two-color screen with 1/16 scan, and can assemble a cost-advantaged LED screen. The control card can be powered off to save information, and the information stored in it can be displayed without connecting to a PC.
3. Connection
It can be divided into data cable, transmission line and power line. The data cable is the cable used to connect the control card and the LED unit board. The transmission cable is used to connect the control card and the computer. The power cord is used to connect the power supply and control card and the LED unit board, and the diameter of the copper core of the power cord connecting the unit board is not less than 1mm.
4. Power supply
The power supply generally uses switching power supply, 220V input, 5V DC output. Besides, because the LED display screen is a precision electronic device, it is necessary to use switching power supply and cannot use a transformer.
What is a LED display packaging
In the production process of LED electronic display, packaging is an indispensable process, what is packaging? It is to package the LED display chip with insulating plastic or ceramic materials to isolate the chip from the outside world to prevent impurities in the air from corroding the chip circuit and causing a decline in electrical performance. And the packaged chip is more convenient for installation and transportation.
Packaging technology is very important, because only packaged products can become terminal products, can be used by users, and the quality of packaging technology directly affects the performance of the LED product itself, good packaging can make LED have better luminous efficiency and heat dissipation environment, and then improve the life of LED, reliable packaging technology is the product to practical and market.
Nowadays, there are three more commonly used LED display packaging methods on the market: DIP, SMD, COB, SIP, three-in-one,…
What is the lifespan of COB LED?
The lifespan of COB (Chip-on-Board) LED is typically quite long, often ranging from 50,000 to 100,000 hours. This extended lifespan is due to the robust design of COB LED, which integrates multiple LED chips onto a single board, improving heat dissipation and overall durability.
Several factors can influence the actual lifespan, including:
1.Operating Conditions: The longevity of COB LED can be affected by the operating environment, such as temperature and humidity. Proper thermal management helps maintain optimal performance and extends lifespan.
2.Power Levels: Running COB LED at or near their maximum power can reduce their lifespan. Operating them at lower power levels or with proper current regulation can help prolong their life.
3.Quality of Components: Higher-quality COB LED typically have longer lifespans due to better materials and manufacturing processes.
COB LED are designed for longevity and can last between 50,000 and 100,000 hours under optimal conditions, making them a durable and reliable lighting solution.
What is a COB package
COB (chip On board) package is to glue the bare chip to the interconnect with conductive or non-conductive glue, and then bond the wire to realize its electrical connection. COB packaging is bracketless technology, without the soldering pin pin of the bracket, every lamp bead and welding wire is tightly encapsulated in the gel by epoxy resin colloid, without any exposed elements.
Compared with SMD-packaged displays, COB LED displays use integrated packaging technology (eliminating the process of packaging and then patching a single LED device), which can effectively solve many problems of SMD-packaged displays, such as increasing process difficulty, low yield and high cost due to the continuous reduction of point spacing.
However, because COB packaging integrates upstream chip technology, midstream packaging technology and downstream display technology, the application of COB packaging in the display industry has not been widely promoted in recent years. In order to realize large-scale application of COB packaging, it needs to be closely coordinated by upstream, midstream, and downstream enterprises.
Why choose COB LED?
Choosing COB (Chip-on-Board) LED offers several advantages, making them a preferred option for many lighting applications:
1.Uniform Light Distribution: COB LED provide a smooth and even light output due to the integration of multiple LED chips on a single board. This minimizes shadows and reduces glare, making them ideal for applications where consistent lighting is crucial.
2.High Brightness: COB technology can achieve high light intensity in a compact form. This efficiency means you can get powerful illumination from a smaller and more integrated light source.
3.Enhanced Heat Management: The design of COB LED allows for better heat dissipation. The LED chips are mounted on a larger, heat-conductive substrate, which helps in maintaining performance and extending the lifespan of the LED.
4.Compact Design: COB LED combine multiple chips into a single module, allowing for a more compact and streamlined lighting fixture. This is beneficial for applications where space is limited or where a sleek appearance is desired.
5.Energy Efficiency: COB LED are known for their energy efficiency, providing high brightness while consuming less power compared to traditional lighting sources. This translates into lower energy bills and a smaller environmental footprint.
6.Durability and Longevity: With improved thermal management and robust construction, COB LED generally have a longer lifespan compared to standard LEDs. This reduces the frequency of replacements and maintenance.
COB LED are chosen for their uniform light output, high brightness, efficient heat management, compact design, energy efficiency, and durability, making them a versatile choice for both commercial and residential lighting applications.
What’s the advantage and disadvantage of COB LED
LED electronic screen is a kind of display device that uses LED light-emitting diodes as display components, which are widely used in various occasions indoors and outdoors, such as advertising, meetings, performances, rentals, etc. LED packaging technology is an important factor affecting its performance and quality, currently there are mainly two ways of package: SMD packaging and COB packaging two ways.
SMD packaging refers to the LED chip packaged in a plastic shell, and then pasted on the printed circuit board by the placement machine to form a single pixel. The advantage of SMD packaging is that the production process is mature, the cost is low, and it is suitable for large-pitch displays. However, SMD packaging also has some disadvantages, such as easy external damage, poor heat dissipation, serious light decay, rough picture, etc.
COB packaging refers to the LED chip directly fixed on the printed circuit board, and then completely sealed with epoxy resin to form a uniform light-emitting surface. The advantages of COB packaging are high stability, good heat dissipation, high light efficiency, delicate picture, suitable for small-pitch displays. Specifically, the COB package LED electronic screen has the following advantages and disadvantages:
Advantages of COB LED
● Anti-collision and wear-resistant: Because the device is not exposed, the COB packaged LED can effectively resist the impact of external impact, friction, vibration and other influences, and is not easy to appear dead lights, dropped lights and other phenomena, improving the reliability and durability of the product.
● Fast heat dissipation: Since the heat is directly dissipated through the printed circuit board, the COB LED has a low thermal resistance value and good heat dissipation performance, which can effectively reduce the working temperature and light decay rate, and extend the life of the product.
● Smaller pitch: Since there is no physical barrier and the shell occupies a lot of space, the COB LED can achieve smaller pixel pitch and higher pixel density, thereby improving the resolution and clarity of the display.
● Higher light efficiency: Since there is no light loss caused by lenses and other parts, the COB LED can achieve higher light output and light efficiency ratio, thereby saving energy consumption and operating costs.
● High quality picture: Due to the use of surface light source luminescence and matte coating technology, the COB LED electronic screen can effectively suppress moiré and glare phenomenon, reduce visual fatigue and glare, and improve viewing comfort.
Disadvantages of COB LED
Although the COB LED electronic screen has many advantages, there are also some disadvantages, mainly as follows:
● High cost: Due to the complex process of COB packaging, large equipment investment and low production efficiency, the cost of COB LED electronic screens is higher and is not suitable for large-scale market promotion.
● Uneven brightness: Since the COB LED electronic screen is composed of multiple units, the brightness of each unit may be different, resulting in uneven brightness of the display screen and affecting the display effect.
● Difficult maintenance: Because the COB packaged LED electronic screen is completely sealed on the printed circuit board, if there is a failure, it is difficult to repair and replace, and the entire module or the entire display screen needs to be replaced, which increases the maintenance cost and difficulty.
● Poor compatibility: Since the COB LED electronic screen is a new type of packaging technology, there is no unified standard and specification at present, and the products of different manufacturers may have compatibility problems, which brings difficulties to system integration and application.
Therefore, the LED electronic screen packaged by COB needs further technical improvement and market development to achieve wider application and development.
Multiple Uses of COB LED
COB (Chip-on-Board) LEDs are highly versatile and suitable for a wide range of applications due to their unique advantages.
1.Commercial Lighting: COB LEDs are ideal for retail and office environments where consistent, bright lighting is needed. Their uniform light distribution reduces shadows and glare, creating an inviting and well-lit space.
2.Residential Lighting: In homes, COB LEDs are used for fixtures like recessed lighting and under-cabinet lights. Their compact design and efficient light output enhance both functionality and aesthetics.
3.Industrial Lighting: For warehouses and manufacturing facilities, COB LEDs provide powerful, focused illumination that improves visibility and safety. Their durability and heat management make them well-suited for harsh environments.
4.Automotive Lighting: COB LEDs are used in vehicle headlights and interior lighting. Their high brightness and compact size allow for innovative designs and improved road visibility.
5.Stage and Studio Lighting: In entertainment and photography, COB LEDs offer precise, even lighting with minimal heat emission. This makes them perfect for stage lighting and studio setups where color accuracy and consistency are crucial.
6.Medical and Scientific Applications: COB LEDs are used in specialized lighting for medical examination lamps and scientific instruments due to their reliable performance and consistent light output.
The adaptability of COB LEDs to various lighting needs—whether for commercial, residential, industrial, automotive, or specialized applications—makes them a valuable choice for providing high-quality, efficient, and reliable illumination.
What’s the process of COB LED display packaging
COB LED display has good look, good picture quality, strong protection, all these characteristics are all attributed to its packaging method COB.
COB LED packaging is to package the light-emitting chip directly on the PCB board, a COB display packaging process flow is as follows: clean PCB — drop adhesive— chip paste — test— Seal and heat to cure — test — storage.
1. Clean PCB board: clean board is to improve the quality of bonding, after cleaning the PCB board still has stains or oxide layer, need to test positioning, with brush or air gun to clean before entering the next process.
2. Drop adhesive: the adhesive usually adopts two ways, one is pressure injection method, and the other is needle transfer;
Pressure injection method: the glue is poured into the container, air pressure is applied, and the caliber of the injection is controlled.
Needle transfer: a rapid dispensing method, using a needle to extract glue from the container and apply it to the PCB board;
The drop adhesive is to prevent the chip from falling off during the bond process.
3. Chip pasting: chip pasting is also called solid crystal, the process requires rigorous, must be “stable and positive”, pay attention to the chip can not have reverse phenomenon;
4. Wire bonding: The purpose is to link electrical and mechanical, and the tensile test done by each company is different, and it can be carried out according to the company’s standards. The wire should be handled lightly, and a special person needs to check its correctness every two hours;
5. Sealing: Check whether there is any dew phenomenon during the sealing process, whether there are pores on the surface, and whether the black glue is cured after that. Packaging has strict requirements for technicians, and the process must be strictly controlled;
6. Test: In the bonding process, there may be undesirable phenomena that are not easy to find, so the chip-level packaging must be tested for performance; There are two ways to detect it: non-contact and contact.
Non-contact detection is mainly visual inspection, and it is also the basic detection technology that must be mastered by COB process personnel, but whether it is non-contact or contact, the relationship between the two should be complementary, not alternative.
What is the difference between ordinary LED and COB LED?
The primary difference between ordinary LEDs and COB (Chip-on-Board) LED lies in their construction and performance characteristics:
1.Construction:
Ordinary LED: These consist of individual LED chips mounted on a small circuit board. Each chip emits light independently, and multiple such LED are often grouped together in a fixture to achieve the desired brightness and coverage.
COB LED: In contrast, COB LED integrate multiple LED chips directly onto a single, large ceramic or metal board. This design creates a compact and uniform light source with a more seamless light output.
2.Light Output:
Ordinary LED: Light is emitted from several discrete points, which can sometimes result in uneven lighting or “hot spots.” To achieve high brightness, multiple ordinary LED are used in a fixture.
COB LED: They produce a uniform light output due to the closely packed LED chips on the same board. This design minimizes glare and provides more even illumination over a larger area.
3.Heat Management:
Ordinary LED: Each LED chip is individually mounted, which can lead to less efficient heat dissipation and potentially shorter lifespans if not properly managed.
COB LED: The design allows for better heat dissipation because the chips are mounted on a larger, heat-sinking substrate. This improves the overall thermal performance and can extend the LED lifespan.
4.Efficiency and Applications:
Ordinary LED: Suitable for a wide range of applications but may require more space and additional components to achieve high brightness.
COB LED: Often used in high-intensity applications where a compact, efficient, and uniform light source is needed, such as in commercial lighting, automotive lighting, and high-end residential lighting.
COB LED offer a more uniform light output, better heat management, and a compact design compared to ordinary LED, making them ideal for applications requiring high brightness and even illumination.
What is the difference between SMD LED and COB LED packaging technology
LED display is packaged into a screen, when it comes to packaging technology, the most commonly used in the LED display industry is SMD technology and COB technology, so what is the difference between these two packaging technologies?
● The meaning is different
SMD packaging technology is to package the light-emitting chip into a lamp bead, solder the lamp bead to the PCB board to form a unit module, and finally spliced into a whole LED screen.
COB packaging technology is to solder the light-emitting chip directly on the PCB board, and then the overall film is coated to form a unit module, and finally spliced into a whole LED screen.
● The image is displayed differently
COB screen is a surface light source, SMD screen is a point light source, so COB screen visual perception is better, and no grain, more suitable for long-term close viewing. COB screen has higher contrast than SMD screen, and the viewing effect of COB screen is closer to LCD screen when viewed frontally, with vivid colors and better details. However, the COB screen cannot sort the similar optical performance of the single lamp beads like the SMD screen, so the COB LED screen is prone to chromatic aberration when squinting.
● Stability, maintainability are different
SMD LED screen, the overall protection is weak, and easy to knock the lamp off, waterproof, moisture-proof, dustproof performance is poor, can not be wiped, but the site maintenance is convenient, conducive to later maintenance.
The COB LED screen has good overall protection, the front protection level can reach IP65, and it can be cleaned with a wet towel, but because the overall lamination site cannot be repaired, it needs to be returned to the factory for repair.
● Power consumption, energy efficiency is different
The luminescent wafer in the lamp bead of the mainstream product SMD screen is mostly a formal installation process, and there are leads above the light source, while the COB screen is mostly a flip process, and the light source is not occluded, so when the same brightness is achieved, the power consumption of the COB screen is lower and has a better economic type. In addition, due to the low permeability of epoxy resin used in SMD lamp bead packaging, the overall film permeability of the COB screen is higher, which further improves the use economy of the COB screen.
● The cost is different
The production process of SMD is relatively complex, but the technical threshold is low, and the vast majority of manufacturers in the country adopt SMD technology, and the technology development is relatively mature. COB production process threshold is high, less than 20 manufacturers in the country have R & D production and manufacturing capabilities. Although the theoretical cost of COB technology is lower than that of SMD screen, the actual cost is not very low at present due to the low product yield.
Conclusion
Since the advent of LED devices for display purposes, it has experienced DIP in-line, dot matrix module, monochrome CHIP type, full-color TOP type, full-color CHIP type, multi-lamp integrated packaging, COB and other packaging types. The emergence of each new packaging form enriches the application types of LED display products. The emergence of COB LED will also bring a large number of new products and applications.
Although the price of the COB package display is not dominant, the COB package LED module is installed with multiple LED chips on the bottom plate, and the use of multiple chips can not only improve the brightness, but also help to achieve the reasonable configuration of the LED chip, reduce the input current of a single LED chip to ensure high efficiency. In the future, COB LED displays may be more widely used.
FAQ about COB LED
COB LED is called COB LED source,COB LED module, meaning that the chip is directly bound to the entire substrate, and all the chips are integrated together for packaging.
COB LED packaging is to package the light-emitting chip directly on the PCB board, a COB display packaging process flow is as follows: clean PCB --- drop adhesive--- chip paste --- test--- Seal and heat to cure --- test --- storage.
Advantages
● Anti-collision and wear-resistant
● Fast heat dissipation
● Smaller pitch
● Higher light efficiency
● High quality picture
Disadvantages
● High cost
● Uneven brightness
● Difficult maintenance
● Poor compatibility
Whether COB (Chip-on-Board) LED is better than traditional LED depends on the specific needs and context of the application.
Uniform Light Quality: COB LED offer superior light uniformity because multiple LED chips are integrated on a single board. This results in even illumination with fewer shadows and less glare compared to traditional LED, which can sometimes produce uneven light.
Brightness: COB LED are generally more efficient at producing high levels of brightness in a compact form. This makes them ideal for applications requiring intense, focused light.
Heat Management: COB LED excel in thermal management due to their design, which promotes effective heat dissipation. This can lead to better longevity and performance under high-power conditions compared to standard LED, where heat management may be less efficient.
Design Flexibility: The compact and integrated design of COB LED allows for more flexible and innovative fixture designs. This can be advantageous for both aesthetic and space-constrained applications.
Energy Efficiency: Both COB LED and traditional LEDs are energy-efficient compared to older lighting technologies. However, COB LED often provide more light per watt, making them slightly more efficient in high-brightness scenarios.
Cost Considerations: COB LED can be more expensive upfront due to their advanced technology and integration. Traditional LED might be more cost-effective for applications where high uniformity and compactness are not as critical.
COB LED generally offer advantages in uniform light quality, brightness, and heat management, making them a better choice for specific high-performance applications. However, traditional LED remain a practical and cost-effective option for many standard lighting needs. The choice between the two should be based on the specific requirements of the application, including light quality, efficiency, design, and budget.
COB (Chip-on-Board) LED offer many advantages, but they do have some disadvantages to consider:
Higher Initial Cost: COB LED typically have a higher upfront cost compared to standard LED. This is due to their advanced technology and integrated design. While they can be more cost-effective in the long run due to their efficiency and longevity, the initial investment is higher.
Thermal Management Challenges: Although COB LED are designed to handle heat effectively, they can still generate substantial heat, especially in high-power applications. This requires robust thermal management solutions to ensure optimal performance and prevent overheating, which can add complexity to the design and installation.
Limited Beam Angle Flexibility: COB LED often have a fixed beam angle due to their design. Unlike traditional LED, which can be paired with various optics to modify the beam angle, COB LED may offer less flexibility in directing light.
Potential for LED Array Failures: In some cases, if a portion of the COB array fails, it can affect the overall light output of the fixture. This is different from individual LED, where failure of one LED might have less impact on the overall performance.
Design Constraints: The compact and integrated nature of COB LED means that they can be more challenging to repair or replace. In some cases, if a COB LED fails, the entire module might need to be replaced rather than just the faulty component.
The lifetime of a COB (Chip-on-Board) LED typically ranges between 50,000 and 100,000 hours. This extended lifespan is due to the efficient thermal management and robust construction of COB LEDs.
Several factors can influence their actual lifespan:
Operating Conditions: COB LEDs perform best and last longer when operated within their recommended temperature range and under stable electrical conditions. Excessive heat or fluctuating power can shorten their lifespan.
Heat Management: Proper heat dissipation is crucial. COB LEDs are designed to handle heat effectively, but inadequate thermal management can impact their longevity.
Usage Patterns: Continuous operation at high brightness levels can also affect the lifespan. Using COB LEDs with appropriate dimming or power control can help extend their life.
Last updated on September 2nd, 2024 at 01:04 am