Ultimate Battle: IMD vs COB
What are they?
LED display have a high demand on photochromic consistency, and the demand increased while the watching distance is lesser than 3 meters. Like traditional SMD, we can run fully inspection on IMD-M09T, after sorting and binning we can filter out the electrical defect. The consistency of photoelectricity can achieve the same level of 1010/0606. For COB, the usual way to mitigate color inconformity is die-bonding with fixed chips(this method also applied to IMD-M09T). After illumining engineers are able to repair the defect, but they can not assure the photoelectric parameter of all LED components are in a reasonable range. Also they need to use Point-by-point calibration technique, with limited effect. Therefore, to obtain a same level on color consistency, COB has pay much more cost than IMD. It is like in a battle, the decisive factor is not the muscle, but the weapon.
More information: The cost of sorting in front-procedure and calibration cost in post-procedure is unavoidable for both IMD and COB, but due to the difference of encapsulating techniques, the cost needed is different.
Besides, for now there are around one thousand PCB factories over the country, but only 2-3 of them can make 8 layers and 3 levels with high accuracy. From this fact we can tell how hard it is to control cost and technical practice. The reason why SMD can achieve mass production(also using 8 layers/3 levels) is that , the request on accuracy is not that high, so it lower the threshold a lot and many factories can make it.) Normally the factories who can make HDI board have the ability to make 6 layers PCB board for IMD. Therefore, from the perspective of technical request or cost, 6 layers/2 levels board that IMD needed is lower than 8 layers/3 levels board that COB needed.
But there are a lot more cost than this for display factory. After production cost, let us go on with maintenance cost.
From the perspective of concept and function, although COB has a certain space to improve, we have to admit that it is a good solution. However, we believe that only the most suitable technical path for end-customer can create great value for the whole industry, also win the market share and become the mainstream choice.