2024-04-10 - tech

Micro LED: A "god" of display

Today, display has become one of the primary channels for information transmission, with mobile phones, VR/AR devices, wearable devices, automotive displays, tablet/computer displays, and laser projections being significant application scenarios for new display technologies.

As the largest base for panel production and manufacturing as well as research and development applications, China has become an important engine for the global development of the display industry. Relevant data indicates that over the past decade, the scale of China's new display industry has continued to expand. Between 2017 and 2021, the scale of China's new display industry grew from 275.8 billion yuan to 586.8 billion yuan, with an average annual compound growth rate of 20.77%, and the industry scale is expected to reach 855.9 billion yuan in 2023.

Among these, the development and industrialization of Micro LED technology have been rapid, with increasing market opportunities attracting many enterprises to enter, thus accelerating the restructuring of the industry landscape. This new star seems to shine particularly brightly in 2024.

01

The Advancements of Micro LED

Micro-LED, also known as mLED or μLED, is composed of an array of micrometer-scale semiconductor light-emitting units and is an electroluminescent device that converts electrical energy into light energy. It can be mass-transferred onto a driving circuit substrate, which can be either rigid or flexible. Subsequently, protective layers and external electrodes are prepared on it using methods such as physical vapor deposition, followed by packaging. The LEDs are made from II-VI and III-V group compounds, such as GaAs (gallium arsenide), GaP (gallium phosphide), GaAsP (gallium phosphorus arsenide), GaN (gallium nitride), and other semiconductors, with the core structure being a pn junction formed by p-type and n-type semiconductor materials.

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When a forward voltage is applied to the LED, electrons and holes are injected into the space charge region from the n-type and p-type semiconductors through the electrodes, respectively, and they recombine and emit light in the junction area. Micro-LED display technology is based on the miniaturization and matrixization of miniature light-emitting diodes (LEDs), with each individual light-emitting unit being less than 50 μm in size and densely integrated on the chip.

Micro LED is a display technology that has been miniaturized to the micrometer scale, characterized by two main features: first, the use of a high pixel density two-dimensional Micro LED array; second, each pixel can be addressed, controlled, and independently driven to emit light.

Micro-LED is a comprehensive technology that integrates new display technology with light-emitting diode (LED) technology. It has the advantages of self-luminescence, high efficiency, low power consumption, high integration, high stability, and all-weather operation, and is considered one of the most promising next-generation display and lighting devices. Due to its small size, high flexibility, and ease of disassembly and integration, Micro-LED can be deployed in any display application scenario ranging from the smallest to the largest sizes. In many cases, it will outperform liquid crystal displays (LCDs) and organic light-emitting diodes (OLEDs) with more unique effects. Compared to LCDs and OLEDs:Self-luminous, high efficiency; low power consumption, about 10% of LCD and 50% of OLED; high brightness, 30 times higher than OLED; ultra-high resolution, over 1500 PPI; high color saturation, 120% NTSC; fast response speed, in the nanosecond range; extremely high contrast; wide viewing angle; seamless splicing can achieve display of any size; service life of over 100,000 hours, etc.

The design concept of Micro LED display panels is to use Micro LED chips directly as display pixels, serving as the basic unit for image formation, thereby achieving image display. Compared to LCD, OLED, and QLED, Micro LED displays have significant advantages, such as: brightness that can reach 10^7 cd·cm^-2, far higher than other display solutions; operating temperature range of -50 to 120 degrees Celsius; no size limitations, etc.

02

Leading Domestic Enterprises

Starting in 2024, Tianma's Tianma New Display Technology Research Institute (Xiamen) Co., Ltd. held the first equipment moving-in ceremony for the Micro-LED production line project. This project is the full-process Micro-LED production line from mass transfer to display module, which was built by Shenzhen Tianma in 2022. The first equipment has been moved in according to the planned schedule, marking a milestone step for Shenzhen Tianma in the field of Micro-LED displays.

Tianma began to explore the field of Micro-LED technology as early as 2017, continuously making breakthroughs in technology and winning various awards at home and abroad. In 2021, Shenzhen Tianma, in conjunction with more than 100 upstream and downstream manufacturers, initiated the industry's first Micro-LED ecosystem alliance; in 2022, the company invested in the construction of the first full-process Micro-LED production line in China, creating a leading Micro-LED technology innovation R&D platform, product application development platform, and an open scientific research achievement transformation platform for the entire industry. Xi Ke Rui, the deputy director of the Tianma Micro-LED Research Institute, mentioned earlier that the company plans to light up and start production of the Tianma Micro-LED production line next year. Currently, 70%-80% of the mass production process technology details have been resolved, and it is expected to start production next year, meeting the demand for small batches in the future.

Regarding application scenarios, Qin Feng, the general manager of Tianma Microelectronics R&D Center, Non-display Business Department, and the dean of the Micro-LED Research Institute, previously stated that Micro-LED is a brand-new technology, and all current scenario forms can be attempted, with the potential to expand into new application scenarios in the future.

Tianma is accelerating the development of Micro-LED technology and processes, and has made significant breakthroughs in high PPI, transparency, curved surfaces, narrow borders, and adjustable transparency, with leading industry technology capabilities. It has also started innovative project cooperation with global leading automotive companies, top domestic PID terminal manufacturers, and leading consumer brand customers. In recent years, Tianma has successively showcased the world's highest PPI Micro-LED display, the world's first small pixel pitch Micro-LED display with >70% transparency, the world's first Micro-LED display with a bending radius of 5mm, and the world's first high-resolution medium-sized Micro-LED display at important professional exhibitions such as SID, CITE, and ICDT at home and abroad. In addition, the 1.63-inch 430 PPI active Micro-LED display showcased at Tianma's Global Innovation Conference on November 27, 2023, features high-definition color and high efficiency, and can be widely used in various downstream fields, including automotive and smart wearables.

On February 20, a project for the production of 20 million sets of silicon-based display chips, modules, and Micro LED driver chip design services signed a contract to settle in the Moganshan High-tech Zone of Huzhou, Zhejiang. It is reported that the investor of the project is Digital Optics Core, with a total investment of about 200 million yuan, planning to build a research and development center, project headquarters, and a silicon-based display driver chip production line. After the overall completion of the project, it is expected to achieve an annual output value of about 500 million yuan and an annual tax revenue of about 40 million yuan.

Digital Optics Core, established in 2019, mainly provides integrated circuit wafers for the silicon-based display driver chip industry. This is a silicon-based micro-display (display with a size of less than 1.3 inches) chip, which mainly includes silicon-based Micro LED, silicon-based Micro OLED, and silicon-based liquid crystal LCoS, etc.Digital Optoelectronics completed a hundred million yuan Series A financing in November 2023, with the funds mainly used for the large-scale mass production of high-process domestic silicon-based display driver wafers, as well as team expansion, improvement of the R&D process, and departmental division of labor. In October of the same year, Digital Optoelectronics successfully debugged and lit up China's first Micro LED silicon-based driving automotive pixel headlight chip, with more than 160,000 pixels.

On June 27, 2023, Chengdu Morningstar Optoelectronics Co., Ltd. signed a contract with Chengdu for a Micro-LED display production base project with a total investment of 3 billion yuan, which will build the world's first TFT-based Micro-LED display production line. The project is expected to be completed and put into production by the end of 2024. Previously, Morningstar Optoelectronics had built a Micro-LED pilot line in Chengdu. On February 22 of this year, the world's first TFT-based Micro LED display production line invested by Morningstar Optoelectronics has entered a rapid construction phase. Currently, the company is working with relevant departments to fully promote the construction of the project, striving to complete the project capping by the end of February this year, when the company will enter for the core production area renovation.

In terms of production line construction, Morningstar Optoelectronics has basically completed the order placement for the production line equipment, some of which has been delivered, and the remaining equipment is expected to be delivered by the middle of this year. Focusing on the research and development and industrialization construction of Micro LED display technology, Morningstar Optoelectronics has successfully lit up 4.78-inch, 14.5-inch, 29-inch, 58-inch, 88-inch, and 102-inch TFT-based Micro LED products, and has made breakthroughs in key technologies such as hybrid driving, mass transfer, and repair.

Chongqing Konka has built the first full-process mass transfer pilot line in China; the most advanced, comprehensive, and strongest detection capability MLED testing center in China; and has built an MLED chip mass production line and an MLED direct display mass production line. Currently, the chip production capacity is about 2,400 wafers/month; the commercial display has completed a 1,000 square meter/month production line. As an important display industry base in China, key enterprises in Chongqing continue to strengthen product research and development, and continuously introduce new products. On the basis of the new display industry cluster completing a value of 76.9 billion yuan in 2023, Chongqing will focus on strengthening the chain this year, accelerating the pace of MLED industrialization, promoting key enterprises to improve panel performance from ultra-high frequency, ultra-high definition, and flexibility, expanding the application scenarios of display panels, and helping the electronic information industry cluster to continue to grow rapidly.

In March 2023, according to DIGITIMES, industry insiders revealed that San'an Optoelectronics, China's largest LED epitaxial wafer and chip manufacturer, will invest up to 7.9 billion yuan (1.24 billion US dollars) to establish Mini LED and Micro LED production capacity at its production base in central China. Sources said that the annual production capacity to be established by San'an Optoelectronics includes 1.61 million pieces of gallium nitride-based Mini LED/Micro LED epitaxial wafers, 750,000 pieces of arsenic-based epitaxial wafers, and 84,000 pieces of Mini LED backlight units (BLU) for 4K displays.

San'an Optoelectronics has become a supplier of Mini LED backlight applications for Apple, Samsung Electronics, and TCL. In terms of Micro LED research and development, San'an Optoelectronics has established a joint venture with China's OLED panel manufacturer Visionox Technology, and another company with China's LCD panel manufacturer CSOT. China's EMS supplier Wingtech Technology, with years of experience in manufacturing automotive semiconductor components, has entered the development and production of Mini LED backlight liquid crystal panels and Micro LED panels for automotive displays.

San'an Optoelectronics has increased its investment in the field of the third-generation semiconductor in the past two years, and has formed four major business sectors: LED chips, microwave radio frequency, power electronics, and optoelectronics. A senior industry insider said, looking forward to 2024, there are some rebound opportunities in the LED chip industry. "San'an Optoelectronics mainly invests resources in the semiconductor field, and the investment in LED chips has relatively decreased. In the case of competitors 'hugging the thigh' and increasing investment, it is necessary to balance the LED chip and semiconductor businesses to better consolidate the industry's position."

On January 31, BOE's Huacang Optoelectronics Zhuhai Micro LED wafer manufacturing and packaging testing base project was capped. The project covers an area of about 217 acres, with an investment of about 2 billion yuan. It will light up the first product in September 2024, plan to mass-produce in December this year, and will achieve an annual production of 58,800 sets of Micro LED wafers in the future. According to data from TrendForce Consulting, the shipment of Mini LED backlight application products in 2023 will increase from about 17 million units in 2022 to 21 million units, and the Micro LED chip market scale is expected to grow to about 32 million US dollars. In addition, according to GGII (Gao Gong Industry Research), the global Mini LED market scale will reach 5.3 billion US dollars in 2025, with a compound annual growth rate of over 85%; the global Micro LED market scale will exceed 3.5 billion US dollars by 2025, and is expected to further break through the 10 billion US dollar mark by 2027.