Views: 1 Author: Site Editor Publish Time: 2024-08-08 Origin: Site
From a macro perspective of the industry, Micro LED's large-scale commercialization is currently facing a series of challenges such as precision, yield, efficiency, and cost. In order to achieve high-performance Micro LED displays, unprecedented manufacturing precision is required, which makes traditional manufacturing techniques no longer applicable. With the continuous development of new technologies, the iterative upgrading of processes has become inevitable, but this has also brought about problems in yield and efficiency, further increasing the cost of various production links, thereby restricting the large-scale industrialization of Micro LED technology. Specifically, the three most critical technical challenges currently include large-scale transfer, TFT backplane manufacturing, and driving technology. Whether these issues can be resolved will directly affect the commercialization and market popularization of Micro LED technology.
Difficulty 1: Large scale transfer
Mass transfer refers to a technology that rapidly and accurately transfers Micro LED chips grown on epitaxial substrates to target substrates, which is a key constraint on the mass production of Micro LEDs. Therefore, whoever can master this key technology first has the opportunity to quickly seize the future display market.
Taking a 4K resolution Micro LED display panel as an example, there are approximately 8.3 million pixels on it, each consisting of three LED chips representing red, green, and blue (RGB) colors. This means that there must be nearly 25 million Micro LED chips on a 4K display panel, which requires LED chip transfer equipment to meet both high efficiency and high yield standards in order to meet the needs of mass production.
The current mainstream methods of large-scale transfer are seal transfer technology, laser transfer technology, or a combination of these two technologies.
Difficulty 2: TFT Backboard Manufacturing
From the perspective of the core integration process and large-scale transfer technology of Micro LED, the TFT backplane using flat panel display technology not only has the advantage of surface flatness over traditional PCB circuit boards, but also can better undertake large-scale transfer processes; However, this technology still faces many challenges and problems in practical applications and production processes.
Firstly, in terms of manufacturing costs, manufacturing TFT backplates requires high-precision equipment and processes, which typically include but are not limited to photolithography machines, chemical vapor deposition (CVD) systems, physical vapor deposition (PVD) systems, etching machines, and cleaning and testing equipment. These advanced devices require high procurement and maintenance costs, which to some extent leads to higher initial investment and production costs.
Next is the practical application of technology. When TFT backplates are used for splicing into large display screens, the technical challenges they face are particularly significant. Especially the implementation of sidewall routing technology and thick copper connection technology are key to ensuring the performance and reliability of large screen displays. During the design phase and manufacturing process, engineers must cleverly arrange the circuit layout and connection methods on the TFT backplane, while ensuring that the overall flatness and stability of the glass substrate are not affected. To achieve this goal, a series of precise engineering techniques and materials science knowledge are involved. For example, sidewall routing technology requires circuit lines to smoothly bend at the edge of the substrate while maintaining signal integrity and low resistance. The thick copper technology involves depositing a thicker copper layer on the substrate to provide better conductivity and thermal management, but this may also affect the flatness of the substrate. These technical challenges have raised higher requirements for production yield and cost control.
Challenge 3: Driver Architecture
Due to the different emission characteristics of LED chips compared to LCD and OLED, existing driving architectures cannot be directly used to achieve Micro LED display. Due to the current emission characteristics of small-sized LED chips, analog driving methods may cause problems such as inability to expand grayscale and high power consumption. In contrast, digital drivers can use a fixed large driving current to adjust the display brightness through different display durations. Only by combining the two can a driving architecture suitable for Micro LED displays be developed.
In addition, the driving circuit in Micro LED displays needs to adjust brightness and color levels through duty cycle. At low gray levels, the driving current is very small, which may lead to unstable brightness and chromaticity. So it is necessary to optimize the design of Micro LED to improve the accuracy of low current driving and display consistency under low grayscale.
In the future, if Micro LED screens want to achieve cost optimization and accelerate penetration into the commercial and consumer electronics markets, the above problems urgently need to be solved.
