“The price of PCB substrate used for mini backlight is higher than the current price of TV LED backlight module.” Qiu Yun, deputy director of Technology Planning Department of BOE display and sensor business group, said at the “2020 global Mini & Micro LED display leaders summit” held recently that the 6-layer 2-level and 8-layer 3-level PCB substrates required for mini backlight can not be supplied in batches in China.

Mini LED backlight: Why did PCB substrate lose to glass substrate?

According to the market research of Gaogong new display, miniled backlight has high requirements for the performance of PCB substrate. At present, the products that can meet the requirements basically need to be imported from abroad or Taiwan.

This also leads to the high price of PCB substrate, and this high cost also extends to mini backlight products.

Since the beginning of research and development of miniled backlight, the whole industry has different opinions on whether it adopts PCB substrate or glass substrate. However, both PCB substrate and glass substrate have their own advantages and disadvantages.

“Due to the limitation of heat dissipation of PCB substrate, miniled will have more chip welding per unit area, and the heat density will be higher than the current LED backlight products, and the PCB substrate will have the problem of warpage and deformation.” the technical director of domestic packaging leading enterprises told high tech new display that although the glass substrate has advantages in cost, its hardness, Easy to crack and other disadvantages are also obvious.

However, the information obtained from several packaging plants shows that glass substrate is the general trend in the future, but PCB substrate is undoubtedly the first choice under the current technical conditions.

The above-mentioned technical director believes that the LED packaging factory is undoubtedly more skilled in the technical scheme of PCB substrate and can be introduced into industrialization faster. At the same time, the yield of mini products of PCB substrate is much higher than that of glass substrate at the current stage.

However, BOE and TCL Huaxing, who are more familiar with glass substrate technology, choose to promote glass based miniled backlight products.

On August 30, 2019, TCL Huaxing launched a new large-size Ammini led mled Xingyao screen with glass substrate. According to the senior engineer’s new display, TCL Huaxing began to layout the mini ledotft backplane in 2018. Compared with the mini ledon PCB backplane pushed by the whole machine factory, the display effect is the same and the TFT drive cost is reduced.

“Glass substrate is definitely superior to PCB substrate in flatness and stability, and also has advantages in cost.” a senior person in the industry told Gaogong new display that in the future, whether Mini backlight is to be applied on a large scale in TV market, flat panel, laptop, etc., panel factory must require glass substrate.

At the same time, due to the current gap in stability and accuracy of domestic PCB substrates, it can not meet the performance requirements of miniled for PCB substrates. The PCB substrates required by miniled need to be imported from Japan, South Korea, Taiwan, etc., and the cost remains high.

“In the first half of the year, especially in March and April, the price of imported PCB substrates increased a lot.” the person in charge of a large packaging factory told Gaogong new display that it is OK to choose one domestic PCB substrate for a small trial, but if it is in batch, the packaging factory will still choose imported products for mini products, which is more guaranteed in terms of stability and accuracy.

According to senior engineering new display, domestic packaging leading enterprises, including Guoxing, Jingtai, zhaochi and Dongshan precision, have not given up their efforts in glass substrate technology while starting to supply PCB based Mini products in batches.

Recently, the new generation minicog of Guoxing optoelectronics has been successfully lit.

It is understood that Guoxing photoelectric’s scheme directly pastes the chip on the glass substrate, which has the advantages of good heat dissipation, excellent cost and high brightness. The key is that the process has no damage to the glass, high efficiency and good consistency, which perfectly solves the frequent quality damage problem of minicog in the process.

In terms of Guoxing optoelectronics, the cog scheme adopts super large-size integrated packaging, primary optical small od thin design, curved surface packaging, etc. it has the advantages of thinner, wider color gamut and more energy saving in applications such as high-order E-sports display. In addition, Guoxing minicob scheme can realize the radius of curvature above r1000 and meet the needs of curved screen.

Some senior people in the industry believe that the glass substrate has been relatively mature in equipment and technology, and is more suitable for the requirements of large-size display.

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