Image source: Hongli Zhihui
According to reports, the P0.4 Micro LED direct display screen using COG technology has high ink color consistency, can achieve higher contrast and better image quality, and performs particularly well in low grayscale. The product uses AM+TFT active drive to achieve high pixel density display, uniform picture transition, and no flicker.
Thanks to the glass substrate material, its flatness, splicability, expansion and contraction are significantly optimized, while its power consumption is lower, and its lifespan, heat resistance, moisture resistance and other characteristics are better.
According to the project leader of the School of Materials Science and Engineering of South China University of Technology, Micro LED currently mainly uses silicon-based materials as the driving backplane, which is costly and difficult to achieve large size, which is not conducive to the promotion of Micro LED. Based on the research foundation in the field of oxide TFT in the early stage, South China University of Technology explored oxide TFT driver arrays suitable for Micro LED, and COG glass-based + TFT driver is recognized by the industry as a better key technology route for realizing Micro LED display.
Compared with the current mainstream PCB substrates, the flatness, stability and high temperature resistance of glass substrates make it easier to achieve mass transfer. COG (Chip on Glass) is a process technology based on glass substrate. It is the best process for producing low-cost, high-pixel density, and large-size LED displays in the future. As the active layer of TFT, oxide materials have the advantages of high mobility, low process temperature, and easy production of LED display screens.
Glass-based + TFT driver uses semiconductor, photolithography and advanced copper processes to achieve an ultra-fine TFT driver structure on a large-area glass substrate. By using COG-packaged row driver chips, it greatly reduces the number of display driver chips used and meets the production needs of large-size Micro LED displays.
In addition, the number of Micro LED display chips is large and the spacing is small. There are two difficulties in achieving mass production. One is whether it can achieve large-scale transfer; the other is the driving method. In addition, glass-based TFT driven Micro LED is a fusion of many technologies, such as COG technology, TFT glass substrate, AM drive and mass transfer, etc., which requires high production and manufacturing links and complex process technology. Therefore, how to overcome key manufacturing processes and improve the possibility of mass production of Micro LED has become an urgent problem for the industry to be solved.
Hongli Zhihui established a joint laboratory with the School of Materials Science and Engineering of South China University of Technology as early as 2020 to focus on the technical difficulties of the Mini/Micro LED process and jointly improve mass transfer technology.
Relying on the R&D technology and manufacturing experience accumulated in the Mini/Micro LED field, Hongli Display completed the key core links such as the die-solidification (mass transfer) process and packaging process for the P0.4 Micro LED display product, and successfully completed a series of trial production processes such as bonding, packaging, and lighting. It overcame the process difficulties of COG transfer technology and Micro LED packaging technology, increased the upper limit of the simultaneous transfer speed of a large number of LED chips, reduced the difficulty of mass transfer, and improved the possibility of Micro LED mass production.
According to the person in charge of the Hongli Display project, P0.4 Micro LED display products have important application prospects in automotive, home theater, virtual shooting, Yuan Universe, 8K ultra-high-definition video and other fields. Based on glass-based TFT drivers, it can meet the production needs of large-size Micro LED displays and will better promote the application of Micro LED displays in large-size panels. (Source: Hongli Intelligence)
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