COB LED screen is a highly integrated LED display screen that uses “chip on board” technology. The LED chip is directly attached to the substrate, which has high reliability, excellent heat dissipation performance and strong protection capabilities. Compared with traditional SMD technology, COB screen supports higher pixel density, delicate display effect, suitable for small-pitch ultra-high-definition display, and is widely used in conference rooms, command centers, outdoor advertising and immersive experience scenes. It is one of the mainstream directions of future LED display technology.
COB LED, or chip on board light-emitting diode is the latest innovation in the field of LED technology. It provides numerous improvements and has already made waves in a few key areas, including lighting and LED display devices. Although greater reliability, energy efficiency, and image quality define most prominent advantages, many customers are still unfamiliar with COB LED display technology and the way it actually works.
In this article, we will explore what chip on board LED technology means, how it’s relevant to display devices and how it differs from other established LED packaging technologies. We’ll also discuss in detail the above-mentioned primary benefits of the COB approach.
What is COB LED Technology
Chip on board (COB) technology is a method of directly mounting red, green, and blue chips onto a printed circuit board (PCB). Packaging the bare chips directly onto the PCB enables a much higher chip density while creating a flat uniform LED surface. The combination of three-color values allows the chips to achieve a higher color gamut and replicate true-to-life imagery.
In other words, with COB LED technology, the number of LEDs that can be placed in any given area of a display is way higher than with other LED packaging approaches, such as Surface Mounted Diode (SMD) and Dual in-line Package (DIP).
Occupying less space on the board without any bonding wires allows for a tighter pixel pitch. The tighter the pixel pitch, on the other hand, the higher resolution. This is one of the reasons behind COB’s breakthrough in the LED packaging world. The potential of improving image quality, reliability, and energy efficiency of a display is huge and will be only further explored in various future applications.
SMD vs. COB Packaging Technology
Before the emergence of the latest COB LED technology, display devices using LEDs relied on other LED packaging processes. The two most common types were SMD and DIP. As the SMD offered superior density and array power, it quickly emerged to be the most popular choice for LED displays.
SMD technology works by using bonding wires to mount the components on the surface of the PCB. This is done using a soldering machine that applies heat and pressure to the joints to create a permanent connection. While this initially represented a major improvement over other techniques, if the soldering is not controlled accurately properly, there’s a bigger risk of weak points in that connection. They may be too weak or too strong, leading to failure.
Besides, SMD components are more susceptible to damage from external factors such as heat and humidity or collision. Since the components are mounted on the surface of the circuit board, they are exposed to the environment and can be easily damaged by external factors.
In contrast, COB technology involves bonding the components to the circuit board using an adhesive, which can provide a more robust and reliable connection. This makes COB technology less susceptible to failure due to external factors and soldering issues. Not needing the bonding wires is also what enables a finer pixel pitch.
Finally, SMD technology is generally limited to components that are larger than 0.5 mm, while COB technology can be used with much smaller components, down to a few micrometers in size.
Benefits of COB LED Technology
With an understanding of what chip on board technology is and how COB LED technology differs from competing technologies, let’s explore what it can do.
1. Superior Pixel Pitch
Essentially, pixel pitch is a measurement of the density of pixels and refers to the distance between the center of one pixel and the center of an adjacent pixel. One of the biggest benefits associated with COB LED technology for display devices, including wall displays and other large-format displays, is precisely the improvements to the pixel pitch. The smaller the pixel pitch, the higher the pixel density thus the higher resolution. The COB LED displays can deliver the tightest pixel pitch which translates to a resolution of up to 4K.
The praised improvements to pixel pitch provided by COB technology are most noticeable when using a display up close because a smaller pixel pitch and higher pixel density will reduce the viewing distance. This means that viewers will be able to stand close to a display and still view it comfortably without noticing the individual pixels.
2. Improved Reliability
When compared to LCD, any LED display will be less impacted by issues like the surrounding environment and various lighting conditions. Once the screen has been set up, it can be used in differently lit situations, without the need to recalibrate the screen.
Among LED displays, the major benefit of COB LED technology specifically, is its improved reliability including water-proof, dust-proof and anti-collision capabilities. The previously mentioned reduction in soldering sites minimizes the possible points of failure. This translates overall to better thermal performance, facilitated maintenance, and, ultimately, peace of mind. Additionally, mounting the LEDs directly on the board also improves moisture- and dust resistance as the surface is protected by a durable clear epoxy resin.
According to the Ingress Protection (IP) rating that defines the level of protection against the ingress of solid objects, dust, and water, COB technology scores IP54 which is a high score for LED displays (by comparison, SMD scores only IP20 or IP30).
3. Great Energy Efficiency
In general, LED technology is more energy efficient than its alternatives, including LCD displays. By the same token, LED technology helps to make display devices much less expensive to operate on a day-to-day basis.
COB LED technology delivers higher energy efficiency than SMD. This is important when it comes to the total cost of operation for large format displays that are going to be used all day, every day for months and years to come.
4. Enhanced Viewing Experience
Finally, COB LED technology has the potential to provide a better all-around viewing experience. While the process of connecting LED chips directly to the printed circuit board allows a COB LED display to deliver a higher contrast ratio, the adoption of flip chips provides wider viewing angles (170 degrees).
COB Technology also drives 4K resolution. This is of paramount importance for large-format displays used in places that need detailed and intricate visuals such as research institutions, engineering facilities, schools of architecture, or fine arts.
When compared to SMD technology, COB LED displays deliver a higher contrast ratio, smoother surface, and better reliability. COB LED technology can result in much-improved brightness and deeper blacks which is great for use indoors where plenty of natural light is present like car exhibition centers, architectural studios, hospitals, and other places that need images of high resolution.
Final Thoughts
Chip on board or COB LED technology is the latest breakthrough in LED packaging technology and delivers especially great results when used in display devices. It tightens pixel pitch, boosts brightness, and improves viewing angles and viewing distances while providing greater long-term reliability and anti-collision, energy efficiency as well as better dust and moisture resistance.
