In recent years, Mini LED has ushered in the large-scale development of commercialization. At present, Mini LED has achieved certain results in the four major fields of TV, automobile, terminal display and VR. Statistics show that in 2021, the global Mini LED backlight TV shipment scale will be 1.8 million units, and it is expected to reach 9 million units in 2025, with a market penetration rate of 4%. It can be found not only in the high-end TV market, but also in the low-end TV market.
Thanks to the active deployment of industrial chain manufacturers such as DSBJ, Nationstar and other manufacturers, the Mini LED backlight has gradually entered the market, giving LCD displays a second soaring development. However, the focus of this article is not the Mini LED backlight technology, but another main track for the development of Mini LED – Mini LED direct display technology.
Overview of Mini LED direct display
Mini LED direct display uses Mini LED chips directly as display pixels to provide the basic unit of imaging to realize image display. Mini LED direct display is still RGB display. The difference is that the size of the LED chip is 50-200 microns, so Mini LED direct display can achieve better RGB three primary colors, bringing a significant improvement in pixel density and resolvable limit distance.
To sum up, compared with the current LED direct display, Mini LED direct display has two obvious performance advantages. One is that Mini LED can be seamlessly spliced in any size, which enriches the usage scenarios of large-size screen display; the other is that Mini LED display has ultra-high-density pixel elements, which can enhance the HDR performance of LED display and greatly improve the display performance including contrast, color depth, and color detail.
From the perspective of the industry development cycle, since Mini LED direct display is to miniaturize and depackage the LED manufacturing process, it is actually consistent with the realization path of Micro LED technology. This makes Mini LED direct display more difficult than Mini LED backlight technology. If you want to make an 85-inch 4K TV, you need a large number of LED chips such as about 24 million, and the cost is very high.
Although the technical difficulty is higher, the current Mini LED direct display industry chain is still making progress, and the industry has entered the initial stage of mass production. For the industry chain distribution, the main difference between Mini LED direct display and Mini LED backlight industry chains is that there are no module manufacturers. The industry chain is divided into three links: upstream raw materials, midstream manufacturing and downstream applications.
Upstream industry of Mini LED direct display
The raw materials of Mini LED direct display include RGB Mini LED lamp beads, glass substrates, chips, printed circuit boards, elastic hard films, phosphors, quantum dots, optical films and protective films. In the cost of Mini LED displays, chips cover the largest investment with accounting for up to 65%. The reason is that a Mini LED direct display requires too many Mini LED chips.
Judging from the distribution of manufacturers, manufacturers currently providing Mini LED backlight beads and LED chips are basically deploying Mini LED direct display technology. For example, Sanan Optoelectronics, HC semitek, etc.
Midstream industry of Mini LED direct display
At present, the manufacturing process of Mini LED chips has also entered the early stage of small batches. The middle reaches of the industry are gradually capable of mass production.
Similar to LED chips, the main manufacturing steps of Mini LED chips are epitaxial material growth, epitaxial wafer inspection, mesa etching, transparent electrode production, metal electrode production, wire bonding plate formation, photoelectric parameter testing, substrate thinning, scribing, etc.
However, due to the smaller size of Mini LED chips, there are certain challenges in the line width accuracy of the production line and chip miniaturization. Although it has a mass production line, the yield rate of mass production is still hard to guarantee, which further increases the cost of Mini LED displays.
In addition, in the midstream of the Mini LED direct display technology industry, packaging and testing manufacturers are also included. Mini LED packaging includes ordinary packaging and mass transfers. In fact, mass transfer is already a Micro LED packaging technology. So this technology is only a transition in the Mini LED stage, mainly to verify the maturity of the technology.
In the middle reaches of the industry, the biggest manufacturing process difference between Mini LED and Micro LED is actually whether the sapphire substrate is retained or not. In the Micro LED manufacturing process, the sapphire substrate has been replaced with a silicon substrate.
In terms of packaging technology, currently available packaging technologies for Mini LED direct display include COB/COG packaging and IMD packaging.
Among them, COB/COG packaging has the advantages of high efficiency, low thermal resistance, better viewing effect, high reliability of anti-collision and pressure resistance. IMD packaging is a compromise solution of COB, because COB packaging has advantages in terms of consistency, yield and maintenance, etc.
Therefore, IMD packaging overcomes the problems of SMD packaging by means of structural integration. Mini LED direct display can also be packaged in MIP, but this packaging method mainly cooperates with mass transfer technology.
Downstream industry of Mini LED direct display
In the downstream of the industry, Mini LED direct display technology mainly has three application scenarios: one is commercial large-screen display of more than 100 inches; the second is VR/AR and other special-sized screens; Screen size has a lot of demand.
At present, in mainstream consumer electronics markets such as TVs, terminal displays and computers, Mini LED backlight technology is more inclined to choose.
From the market size, the three major terminal markets that Mini LED displays are oriented to have a certain scale. According to statistics, China’s commercial large-screen display market shipments reached 9.53 million units in 2022 with an increase of 11.4% year-on-year, and the giant-screen TV and splicing screen markets increased by 4.5% and 11.6% respectively.
Although the VR and AR shipments declined in 2022, TrendForce forecast data shows that global VR/AR shipments are expected to reach 43.2 million units in 2025, more than three times the current shipments.
The global automotive display market scale exceed 10 billion USD in 2022 and is expected to continue to grow in the next few years.
Conclusion
From the perspective of industry development, the Mini LED direct display lags behind Mini LED backlight. Many analysts predict that Mini LED direct display will have fast development in 2024. In the current stage, the industry is mainly limited by chip manufacturing yield and cost issues.
However, based on the industry development trajectory, Mini LED direct display is a transitional product. The ultimate goal of the industry is Micro LED direct display. The key point for Mini LED direct display technology is how to break through the bottleneck like mass transfer or other technologies. How to select a LED PCB supplier is also important. We have collected the top 15 global LED PCB suppliers in 2022 for you to refer.
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