Advantage of COB LED 4K LED Video Wall 3840Hz

SMD full-color: This product has high raw material costs and complex production and processing techniques, resulting in high investment and cost.
COB full-color: COB eliminates the concept of brackets, without electroplating, reflow soldering, or surface mounting, reducing the number of processes by 1/3. In terms of solidification and wire bonding processes, the efficiency of COB packaging is comparable to SMD, but in terms of dispensing, separation, spectroscopy, and packaging, the efficiency of COB packaging is much higher. The labor and manufacturing costs of traditional SMD packaging account for about 15% of material costs, while COB only accounts for 10%, and the cost is at least 5% higher than SMD full-color packaging.
Optical electrical properties
COB full-color has good color consistency, large viewing angle, uniform light spot, high brightness, and good color mixing effect, which are the characteristics and advantages that SMD full-color and dot matrix full-color cannot surpass.
Large viewing angle and high brightness, COB adopts heat sink technology, which can ensure that the LED has an industry-leading heat flux maintenance rate (95%). The following are comparison pictures of the appearance and angle light shape of adhesive and SMD
COB full-color appearance diagram SMD full-color appearance diagram
COB has better visual consistency. From the appearance alone, it can be seen that there are hundreds of light-emitting points on the dot matrix board that are all on the same PCB board, that is, on the same horizontal plane. Therefore, the light-emitting points are all on the same reference point, resulting in a more uniform light spot. However, SMD is attached to the PCB board one by one, which will definitely have high and low spots, resulting in uneven light spots and a visual effect worse than that of COB packaging.
COB has better light quality. As can be seen from the following figure:
The traditional packaging form of SMD in the right figure is to mount multiple discrete devices on a PCB board to form LED applications. This approach has issues with point light, glare, and ghosting, as is evident from the diagram; COB is an integrated package and a surface light source, which not only has the advantage of a large viewing angle, but also reduces the loss of light refraction.
COB has a larger perspective. From the following light diagram, it can be seen that the viewing angle of the Oreda COB full-color is much larger than that of the SMD full-color. The SMD full-color viewing angle is about 110 degrees, while the COB full-color viewing angle can reach 140-170 degrees without reducing brightness, and the vertical angle also has a wide viewing angle of 140-170 degrees. These characteristics are particularly advantageous in some application scenarios. Here is a comparison of the two light diagrams:
COB angle light pattern SMD angle light pattern
From the actual luminous effect diagram, it can be seen as follows:
Glue dispensing luminous effect diagram SMD luminous effect diagram
From the above comparison, both in terms of viewing angle size and luminous effect image, the visual effect of COB full-color is superior to SMD full-color.
Solid crystal placement
COB fixed crystal placement method: RGB chips are placed in a straight line, and the lens above the chip is a smooth curved surface. The lens has a good refraction effect on light. When the three colored light passes through the lens, refraction occurs, making the three colored light mix more evenly, resulting in good color mixing effect and uniform spot, giving a better visual effect and more realistic display effect. However, SMD full-color does not have this characteristic because the SMD top is a flat surface, so the refraction effect is average, so the color matching effect is worse than COB. The following is a comparison of the two light distribution curves, which can more clearly see the advantages of COB full-color:
COB full-color R/G/B light distribution curve SMD full-color R/G/B light distribution curve
From the light distribution curve graph, it can be seen that the COB full-color curve has good consistency among the three, while the SMD full-color curve has poor consistency. The red light curve has a significant separation from the blue/green light curve, so the effect is worse than that of COB full-color.
reliability
Low thermal resistance
The system thermal resistance of traditional SMD packaging applications is: chip die bond solder joint solder paste copper foil insulation layer aluminum, while the system thermal resistance of COB packaging is: chip die bond aluminum. Obviously, the system thermal resistance of COB packaging is much lower than that of traditional SMD packaging, which greatly improves the life of LED.
In addition, the Oreda COB adhesive chip is directly fixed on the PCB board, so the heat dissipation area is large, which makes it difficult for the chip junction temperature to rise, resulting in good light attenuation and stable product quality; SMD chips are fixed in the bowl and cup, not in direct contact with the PCB board, resulting in a small heat dissipation area and poor heat dissipation performance, which can lead to an increase in chip junction temperature and significant light attenuation. And these reasons are precisely the bottlenecks in the development of SMD full-color technology.
Waterproof, moisture-proof, and UV resistant
COB, due to its packaging method of using glue on the board to form lenses, performs well in terms of waterproofing, moisture resistance, and UV protection when applied outdoors, while SMD generally uses PPA material brackets, which are poor in waterproofing, moisture resistance, and UV protection. If the problems of waterproofing and moisture resistance are not solved well, it is easy to encounter quality problems such as failure, dullness, and rapid decay.