Terminal demand and policies drive the rapid development of the Micro LED industry

Micro LED is display technology hexagonal warrior. More than 80% of human information is obtained through the eyes, and human's higher requirements for display image quality and shape drive the continuous development and iteration of display technology. Color display technology has experienced transition technologies such as CRT since its development, and is currently dominated by LCD and OLED technology. In terms of performance, Micro LED as the next generation display technology, compared with the large-scale production of LCD technology (liquid crystal display) and OLED technology (organic light-emitting diode display), Micro LED has a very superior performance advantage in almost every technical dimension: Long life, high contrast, can achieve high resolution, fast response, wider viewing Angle effect, rich color, is regarded as the ultimate solution of display technology.

First, cost and performance drive the Micro LED industry continues to develop

Micro LED is a new LED miniaturization and matrix technology, which refers to the integration of a high-density micro-size LED array on a chip. The technology achieves single-point drive self-lighting by miniaturizing the LED unit to a level of less than 50 microns, which is ~ 100 times smaller than traditional leds and reduces the pixel pitch from millimeter to micron. Therefore, the Micro LED is essentially a micron-level LED, and the LED light-emitting diode is a solid-state semiconductor device that can convert electrical energy into visible light.

In terms of cost, a 4-inch sapphire epitaxial sheet, cut into ordinary LED chips about 60,000, cut into Mini LED chips about 600,000, cut Micro LED chips in more than 2.4 million. The same wafer, the number of Micro LED has been significantly increased, and the cost of a single chip is lower, which is also one of the reasons for the development potential of Micro LED from the cost point of view.

In terms of performance, compared with LCD technology and OLED technology that have been mass-produced, Micro LED has very superior performance advantages in almost every technical dimension, such as long life, high contrast, high resolution, fast response, wider viewing Angle effect, rich color, ultra-high brightness and lower power consumption. Among them, (1) thin and light: the size of the Micro LED is about 1/100 of the traditional LED, or about 1/10 of the width of a human hair; (2) Low power consumption: Micro LED uses three primary color sub-pixel self-luminous structure, LCD display process needs to use backlight to polarizer and then to color filter, the display process has a lot of energy loss, compared with the two, in the display application of Micro LED power consumption is about 10% of the LCD power consumption. Micro LED uses inorganic materials to emit light, which has higher luminous efficiency, and OLED uses organic materials to emit light, and the luminous power consumption of both is lower than that of OLED. Therefore, in the display of the same picture, the power consumption of Micro LED is lower than OLED, and much lower than LCD; (3) High brightness: the Micro LED uses gallium nitride (GaN) inorganic material in the luminous part, and its brightness can theoretically reach 105cd/m2, much higher than the 3,000cd/m2 of LCD and 1,500cd/m2 of OLED, and the service life of inorganic materials is longer; (4) High resolution: under the Micro LED display technology, each Micro LED is a pixel that can self-light, and a single Micro LED is at the micron level, so it can achieve very high resolution. The pixel density of the Micro LED display can be more than 1,500PPI, while the LCD and OLED screen PPI is about 800PPI and 400PPI.

In summary, cost and performance will promote the continuous development of the Micro LED industry.

Second, Micro LED application scenarios

Micro LED is the ultimate display technology of the future. If you do not consider the cost and process maturity, only look at the performance and indicator data of the display, Micro LED is undoubtedly the ultimate display technology, Micro LED all performance indicators are better than other display technologies. In terms of application scenarios, Micro LED is suitable for all sizes of product applications. From the perspective of technical feasibility and economic feasibility, Micro LED will be the first to be applied to small size displays below 3 inches and large size displays above 100 inches.
In terms of small display sizes below 3 inches, Micro LED will erode the OLED market. Small size display because the viewing distance is very close, the display effect requirements are high, and small size display is common in mobile terminals, and it also has high requirements for power consumption. Therefore, OLED has become the mainstream technology for small-size display with its advantages of low power consumption and good display effect, but the market share of OLED in this field will be eroded by Micro LED in the future. On the one hand, Micro LED is superior to OLED in all display performance indicators such as display effect and power consumption; On the other hand, due to the small screen size and the small total number of pixels, the cost of Micro LED is also relatively controllable. From the current technology point of view, Micro LED has been able to achieve chip miniaturization, but there are still some bottlenecks in the huge transfer, the yield is relatively limited, at present, various companies are exploring technical improvement solutions on the basis of controllable costs.

In terms of 3-99 inch display, Micro LED is difficult to erode the market share of LCD and OLED in a short time. Due to the close viewing distance, the display has higher requirements for chip size and pitch, while the screen size becomes larger and the total number of pixels also becomes more, so the Micro LED applied to the 3-99 inch display has significantly increased the technical difficulty and cost of the process, and the Micro LED technology maturity in this range needs to be improved. And the most critical is that this size area, whether small size OLED and large size LCD, its cost advantages are firmly unshakable. In the future, with the continuous reduction of the cost of Micro LED and the continuous improvement of technology, the gap between the cost and process difficulty of Micro LED and LCD and OLED will be further narrowed.

In terms of large displays of more than 100 inches, Micro LED has the advantage. In the display market of more than 100 inches, LCD will be limited by the production yield and cutting efficiency of large-size panels, and OLED is also difficult to achieve a reduction in cost due to the evaporation process after large-size, lower yield, so in the past, the display effect is more general projectors and LCD splicing screens occupy a dominant position in the display market of more than 100 inches. However, with the significant decline in the cost of Micro LED, it will accelerate the replacement of traditional display products such as projectors and LCD splicing with many advantages such as full-screen splicing, rich color and high brightness.

Three Micro LED industry market size

At present, Micro LED chips have been productized in display scenes such as glasses and TVS, but most products are still in the concept stage due to price restrictions and have not yet achieved large-scale market promotion. In the future, with the breakthrough and gradual maturity of the key technology of Micro LED, the commercialization and industrialization cost is greatly reduced, and the chip yield is further improved, Micro LED is expected to take the lead in the application of large size and small size display scenarios. From the shipment point of view, according to Omdia forecast data, affected by smart watches and high-end TV market demand, the global Micro LED display shipments will soar from the negligible level in 2020 to more than 16 million pieces in 2027, and the market demand potential is large. From the market size, according to Jibang Consulting forecast, in the micro-display application scenario, it is expected that in 2026, the output value of Micro LED AR glasses display chip is as high as 41 million US dollars; In the large-size display scenario, the output value of Micro LED large display chips will reach $54 million in 2022, and is expected to rise to $4.5 billion in 2026, with a compound annual growth rate of 204%, and there is a lot of room for market growth.

Fourth, terminal demand and policy drive the rapid development of the industry

(1) Changes in terminal demand are the main factors driving the development of the industry

Since 2009, the LED chip industry has experienced three cycles, all driven by new demand for LED products. The first stage is before 2013, flat panel TV and mobile phone backlight as the main demand for LED to drive the development of LED industry, the second stage is 2013 to 2014, 2013, the European Union completely banned white woven lights, the demand for LED professional lighting and landscape lighting rise, coastal LED exports rise to drive the development of LED industry; The third stage is from 2015 to 2020, the rapid development of small-pitch LED, a large number of replacement LCD and DLP, widely used in government command centers, security, disease control, business, night travel and other fields, thereby driving the development of the industry; The fourth stage is that after 2020, the LED display industry's demand for high-definition display and low power consumption has gradually increased the penetration rate of Micro LED. As the ultimate display technology, with cost reduction and technological progress, Micro LED will speed up the industrialization process of Micro LED with superior performance such as long life, high contrast, high resolution, rich color, ultra-high brightness and lower power consumption, and is expected to drive the industry to enter the rising cycle again.

(2) Strong support from national policies will drive the development of the industry

As the next generation of new display technology, Micro LED has attracted much attention. In recent years, the state has promulgated a number of supportive policies, such as the "14th Five-Year Plan" in 2021, which clearly states that the third-generation semiconductor is an important content, and the project covers key technologies such as new energy vehicles, big data applications, 5G communications, and Micro LED display. The Ministry of Industry and Information Technology and other five departments issued the "Virtual reality and industry application Integration Development Action Plan (2022-2026)", which will focus on promoting Micro LED and other micro display technology upgrades; The Ministry of Industry and the Ministry of Finance issued the "Electronic Information Manufacturing Industry 2023-2024 stable growth action Plan" proposed to vigorously develop Mini LED, Micro LED and other technologies; The Ministry of Industry and Information Technology and other seven departments jointly issued the "Implementation Opinions on Promoting Future Industrial Innovation and Development", which proposed to break through Micro LED, laser, printing and other display technologies and achieve large-scale application. The release and implementation of the above policies and regulations shows the positive attitude and firm determination of the Chinese government to develop the Micro LED industry, which provides a better development environment for the development of the Micro LED industry. Micro LED is expected to benefit from the policy support of the state and usher in rapid development.

Five, the development of the Micro LED industry

(1) Industry development status

The Micro LED manufacturing process is similar to the conventional technical steps, mainly including LED epitaxial wafer growth, Micro LED chip production, driver backplane (TFT driver or Micro IC driver) production, large transfer of four parts. First of all, the LED structure design is thin film, Micro, array, and then the Micro LED is transferred to the circuit board using a large amount of technology, the substrate can be hard, soft transparent, opaque substrate; By using the physical deposition process to complete the protective layer and the upper electrode, the upper substrate can be packaged and a simple Micro LED display can be completed. However, due to the miniaturization of the chip, Micro LED manufacturing technology has put forward new technical indicators and requirements for each link of the existing industrial chain, including the research and development needs of key technologies in various fields such as materials, processes, and equipment, and the technology of each industrial link can not be independently developed, it is a very complex technical system. It is necessary to closely cooperate with the upstream and downstream of the industrial chain such as panels, chips, massive transfers and driver ics. At present, the four key technologies of epitaxy & chip manufacturing, massive transfer, full-color display, and display drive still need to be broken through.

(2) Overview of global technological innovation

From the perspective of the development history of Micro LED, two professors at Texas Tech University took the lead in proposing the concept of Micro LED in 2000, and it has now entered a high period of global technological innovation. Since 2017, the innovation activity of Micro LED technology has increased significantly, and it is currently in a period of explosive growth. At present, Micro LED has a global patent reserve of more than 40,000, of which more than 13,000 are valid patents, and the sum of the examination and validity ratio is close to 80%, indicating that the potential patent barriers in this field are high; From the perspective of the more active area of Micro LED technology innovation, the more active area of technology innovation is in China, the United States and South Korea, and the region of patent layout shows that the more active market is in China and the United States. From the perspective of the major innovation entities in the world and China, the global leading innovation entities in China, South Korea and the United States have more advantages, mainly in the display panel and photoelectric enterprises. Among the world's top 15 enterprises, Chinese enterprises accounted for more than half, BOE, Huaxing Optoelectronics ranked in the world's top 5; In addition to China's leading enterprises, South Korea's Samsung and LG patent layout ranks at the forefront of the world. From the distribution results of the number of patents by the type of R&D institutions, start-ups are the highest, reaching 29%. From the perspective of patent types, the number of patents is distributed around the four key technologies of epitaxy and chip structure, massive transfer, full-color display, and display driver.

(3) The development of four key technologies

Epitaxy and chip manufacturing: The Micro LED manufacturing process from wafer to chip needs to go through steps such as epitaxy - step etching - conductive layer preparation - electrode preparation. In the direction of epitaxy & chip structure technology, for smaller Micro LED, the current industry is mainly concerned about wavelength uniformity, low epitaxy defect and quantum efficiency issues: (1) After the chip is miniaturized, there are high requirements for epitaxy wavelength consistency and low defect rate, traditional LED requires 6-12nm, Micro LED chip is required to be reduced to 2nm; (2) The chip size is getting smaller and smaller, and the cutting fragment yield is decreasing; (3) The efficiency of Micro LED will increase with the increase of current density, and decrease with the increase of current density after reaching the peak value. As the size of the Micro LED decreases, the peak efficiency moves to the direction of high current density, and the peak efficiency continues to decrease.

Large transfer: Due to the difference in the growth process of the Micro LED luminous layer and the driver substrate, it is difficult to integrate the display array and the driver device through the growth process, so it is necessary to transfer the made Micro LED grains to the drive circuit board, which is a large transfer process. Taking a 4K TV as an example, the grains that need to be transferred are as high as 24 million (calculated in 4,000 x 2,000 x RGB three colors), even if a transfer of 10,000, it needs to be repeated 2,400 times, so the huge transfer faces three major problems: (1) transfer accuracy: The accuracy of moving the Micro LED to the drive circuit board must be controlled within ±0.5μm, and the transfer device must have high alignment accuracy and drop point accuracy. (2) Transfer efficiency: traditional LED 2 pieces/second, Micro LED requires 20,000 pieces/second; (3) Transfer yield: Display products for pixel error tolerance is very low, if you want to create less than 5 pixels of the full color 1920*1080 display, transfer yield must reach 99.9999%.

Large transfer technology mainly includes molecular force (seal transfer), electrostatic, magnetic transfer, laser transfer, self-assembly (fluid assembly technology) and so on. Laser large transfer can control the size of the relatively small, fast response, high transfer efficiency, and has a high degree of selectivity, laser transfer or will become the mainstream technology of large transfer. At present, the domestic large transfer technology and equipment progress, manufacturers of large laser (002008), leading intelligence (300450), Haimu star laser and other large transfer equipment has been successfully shipped, delivered to customers, but domestic laser equipment from large-scale mass production is still a long way away.

Full color display: Micro LED to achieve monochrome is relatively simple, but to achieve full color is relatively complex, RGB three colors need to transfer red, green and blue three color grains. As the key technical index of Micro LED technology, the research of Micro LED full color technology has become a research hotspot and difficulty in the development of Micro LED technology. The realization methods of Micro LED colorization mainly include RGB three-color LED method, UV blue LED+ luminescent medium method and lens synthesis method, all of which have corresponding shortcomings. In comparison, in terms of process flow and materials, the UV blue LED+ light-emitting medium method is simpler than other schemes, mainly using blue LED to replace the backlight plate, using quantum dot film or phosphor as the light-emitting medium to replace RGB filters, to complete the full-color display.

Display driver: The active driver design scheme represented by CMOS and TFT has become the mainstream of Micro LED technology development. Micro LED is a current driven light-emitting device, and its driving mode is generally divided into PM(Passive Matrix) passive drive and AM(Active Matrix) active drive. Because of the passive drive: (1) is not conducive to large-area production, can not meet the requirements of large-screen drive; (2) Column scanning drive characteristics, easy to produce column pixel light uneven, resulting in display image and resolution limited; (3) The pixel pitch is gradually shrinking, the passive drive mode of the traditional PCB board can not meet the drive demand, and has many disadvantages in the application of Micro LED, therefore, the active drive design scheme represented by CMOS and TFT will become a good companion for the development of Micro LED technology. For example, in CMOS driver technology, in order to break through transfer bonding technology, the current industry focuses on exploring the bonding technology of Micro LED and CMOS driver circuit.