Micro LED large-sized displays will move towards the home theater and high-end commercial display markets and the revenue of Micro LED large-sized display chips is estimated to reach US$54 million in 2022, according to TrendForce’s latest research. By 2026, revenue is expected to grow to US$4.5 billion with a compound annual growth rate of 204%. In addition, technical obstacles will be conquered one by one over time. The development of Micro LED large-sized displays will peak from 2026 to 2030 and the one year revenue of Micro LED chips has the opportunity to reach tens of billions of dollars.

In recent years, major global brands in various regions have released Micro/Mini LED self-emissive large-sized display products. Samsung, the world’s leading TV manufacturer, released a 146-inch TV, “The Wall,” in 2018 and continues to release 75-inch, 89-inch, 101-inch, 110-inch, 219-inch, and 292-inch large tiled wall displays at CES every year. Due to the evolution of different application scenarios and technologies, the future development trend of Micro LED large-sized displays will be in home theaters, corporate headquarters, and boutique stores. Commercial indoor and outdoor large-sized displays are mainly based on Mini LED self-emissive large-sized displays. In order to satisfy the requirements of close indoor viewing, Micro LED large-sized displays require a theater-level experience, seamless tiled display splicing, pursuit of zero borders, thin design, and competitive pricing. Thus, active matrix (AM) would be the first choice for display design.

TrendForce states, current Micro LED large-sized displays still face the dual challenges of technology and cost including Micro LED chip cost, and the three key technologies of backplane technology, driving technology, and the mass transfer process. In terms of Micro LED chip cost, due to the enormous number of chips used and the need for consistent wavelength uniformity to achieve perfect display quality, the clean room level requirements for epitaxial and chip processes, control of process conditions, and inspection and maintenance during processes are very strict, greatly increasing relative process defect rate and overall cost. In terms of mass transfer, the current mass transfer technologies used in Micro LED large-sized displays include pick-and-place technology and laser transfer technology, each with its own advantages and disadvantages. TrendForce believes that, although current Micro LED mass transfer technology is still in the product development and adjustment stage, there have been no real quantitative achievements. However, in terms of pick-and-place mass transfer equipment capacity, using 10cm2 transfer stamps to transfer 34*58µm Micro LED chips, production capacity (UPH; Unit per Hour) is approximately 7 million units. If the laser mask opening of laser mass transfer technology is 8 square millimeters, production capacity is approximately 12 million units. No matter which kind of transfer technology, the mass transfer capacity of Micro LED large-sized displays needs to reach at least a 20 million unit level of efficiency and 99.999% yield in the future to meet the conditions for mass commercialization.

Active matrix design will abet the development of Micro LED technology

In terms of backplane and drive technology, passive matrix (PM) drive design is based on a PCB backplane with a passive drive circuit structure, using MOSFET as the current switching element. Therefore, overall structure is more complex and requires a wider placement area for circuit components. In addition, when dot pitch is reduced to less than P0.625, the PCB backplane will encounter the challenges of line width and line space mass production limitations and rising cost. Thus, the current technological state of the passive matrix (PM) drive design is more suited to large-sized display applications utilizing dot pitches greater than P0.625 and equipped with a Mini LED. However, for consumer Micro LED TVs employing a dot pitch less than P0.625, active matrix (AM) drive design will become the new direction of display design. Since a TFT glass backplane with LTPS switching technology is considered mature technology by panel manufacturers, it is necessary to adjust certain portions of the manufacturing process and parameters to precisely control and drive Micro LED current.

In addition, in order to achieve seamless tiled display splicing technology, glass metallization and side wire electrode glass will become further technical challenges. As resolution moves higher and the dot pitch is reduced, the front circuit of TFT glass must be guided to the back along the side or by using through-holes. At this time, glass metallization technology becomes key. Since current glass metallization technology is still afflicted with technical bottlenecks resulting in high cost due to low yield, when these bottlenecks are resolved with future technology, the launch of mass production glass metallization will become the advantage of active matrix backplanes. Future active matrix (AM) drive design with Micro LED chips and seamless splicing technology have the opportunity to become the mainstream technology of Micro LED TV development and the key to unlocking a new wave of Micro LED large-sized display cost optimization.

Annual revenue of Micro LED chips for TV is expected to reach US$3.4 billion in 2025 at a 250% CAGR across the 2021-2025 period, according to TrendForce’s latest report titled 2021 Mini / Micro LED Self-Emissive Display Trends and Analysis on Suppliers’ Strategies. This growth can mostly attributed to the early planning by display manufacturers to adopt Micro LED technology for large-sized displays; although the prohibitive cost of this technology is unlikely to be overcome in the short run, TrendForce still forecasts the aforementioned revenue in light of several factors: First, Micro LED technology enables the production of gapless, large-sized modular displays; second, displays featuring Micro LED technology are able to meet the standards of cinema-grade displays or high-end TVs; finally, Korean TV brands have been aggressively investing in Micro LED TV development.

After TV market leader Samsung released its 146-inch TV wall, aptly named “The Wall”, in 2018, the company has continued to announce large-sized modular video walls and Micro LED TVs (which come in such sizes as 75-inch, 110-inch, 219-inch, and 292-inch) at each subsequent CES. TrendForce indicates that, prior to the widespread commercialization of Micro LED TVs, TV manufacturers will continue to face challenges in terms of both technological barriers and costs. In particular, breakthroughs in three areas remain the most noteworthy: Micro LED chips, backplanes/drivers, and mass transfer.

With regards to cost, Micro LED chips comprise the highest share of Micro LED TV manufacturing costs, and their persistently high prices can be attributed to three factors. The first of these factors is the enormous number of chips used in TV manufacturing. For instance, a 4K resolution TV requires 24.88 million Micro LED chips. Second of all, due to the diminutive size of Micro LED chips, their manufacturing process involves extremely stringent requirements regarding wavelength uniformity and clean room particle count. Finally, as Micro LED chips are smaller than 75μm­, the current PL (photoluminescence) technologies are unable to fully detect defects in Micro LED chips, in turn increasing the difficulties in the mass transfer process of chips to backplanes.

With regards to backplane and driver technology, PCB backplanes paired with passive matrix (PM) are a relatively mature solution that has become the predominant choice for P > 0.625mm pixel pitch displays. However, for Micro LED TVs, which are relatively smaller in size but maintain the same resolution, once their pixel pitch shrinks below 0.625mm, challenges begin to arise with PCB backplane development, such as line width and line space, both of which can pose limits on mass production and increase manufacturing costs. Conversely, TFT glass backplanes paired with LTPS arrays are able to accurately control and drive the electrical circuits in Micro LED displays. This type of active matrix (AM)-equipped backplanes is therefore expected to become the mainstream technology of Micro LED TVs going forward.

Another technological challenge in backplane development is glass metallization. As displays approach increasingly high resolutions, they require correspondingly smaller gaps between modules. Now that traditional COF (chip on film) designs are no longer viable, manufacturers are instead routing the wirings on the surface of the TFT glass either from the side or through TGV (through glass via) processes. In order to achieve this routing, manufacturers need to make use of glass metallization technology. However, as many technological bottlenecks still remain with regards to glass metallization, such as low yield rate and high cost, manufacturers must work to overcome these barriers as the industry moves forward.

In terms of manufacturing process, the main hurdles in Micro LED development are twofold: mass transfer and testing/repairing. The 24.88 million Micro LED chips used in each Micro LED TV pose an enormous demand in terms of mass transfer yield rate, manufacturing time, and testing/repairing processes. At the moment, the industry’s predominant mass transfer technologies consist of pick and place, laser transfer, fluidic assembly, magnetic mass transfer, roll-based transfer, and wafer bonding.

The adoption of each respective mass transfer technology depends on the resolution of the display products as well as the size of Micro LED chips to be transferred, and each of these technologies comes with its own impact on production capacity, yield rate, and manufacturing equipment costs. That is why Micro LED production lines involve such a high degree of complexity. TrendForce believes that the mass transfer process in Micro LED TV manufacturing needs to reach a rate of at least 20 million UPH (units per hour) and a 99.999% yield for Micro LED TVs to be viable for wide commercial release.

For more information on reports and market data from TrendForce’s Department of Optoelectronics Research, please click here, or email Ms. Grace Li from the Sales Department at graceli@trendforce.com