However, in the past 202 1 year, more and more people in the industry have realized that the pronoun that will completely change the LED display industry pattern may not be mini-led or micro-LED, but COG technology and TFT glass substrate behind COG technology.
What is COG technology
The application of COG technology in LED display can be simply summarized as: LED display unit packaging technology in which LED luminescent crystal is directly packaged on TFT glass substrate. This technology has three main characteristics: 1. Direct packaging of LED dies is a huge operation at sub-wafer level. 2. The backplane circuit adopts new products such as TFT glass substrate to replace the traditional PCB circuit board; 3. The working mode of 3.LED die is AM active driving, not traditional PM passive driving.
From the development history of LED display products, it has experienced direct insertion technology, SMD surface mount technology and COB technology. Among them, the difference between COB and traditional SMD surface mount package is that COB technology directly integrates LED chips of light-emitting chips into PCB board. That is to say, direct operation of LED dies and batch operation. Compared with COG technology, the further difference is 1. COG uses glass substrate and AM driver to replace traditional PCB substrate; 2. The 2.LED die consists of 2. COG technology tends to be both bigger and smaller.
The core reason for the development of COG technology is that the smoothness of glass substrate is more suitable for the synchronous operation of a large number of LED chips with huge transfer technology. The upper limit of mass transfer technology is greatly improved, and the difficulty of mass transfer and process error factors are reduced.
In fact, the core difference from in-line technology, SMD surface mount technology, COB technology to COG technology is that "the pixel spacing of LED display screen is getting smaller and smaller, and the integration scale of LED die per unit display area is getting higher and higher." -This is also the main direction of small-pitch LED display, micro-pitch LED display and mini-led to micro-LED technology.
Therefore, many enterprises in the industry believe that if mini-led or micro-LED display technology is further upgraded to products with higher pixels per inch, COG technology or large-scale transfer technology on glass substrates will be necessary "basic technology". However, the change and revolution of COG in LED display industry is far less than that in the external supply chain of LED display industry.
Changes from PCB to TFT glass substrate
An LED display company hopes to develop LED display products based on COG technology. The core technology and component support mainly include: 1.mini-led or micro-led LED LED die, 2. Driving IC suitable for COG, 3. Its own huge transfer technology, and 4. Suitable batch supply chain for TFT glass substrates.
Among them, the core technologies of LED display terminal enterprises mainly focus on massive transfer and terminal module packaging; The other three aspects all need "external procurement". However, the upstream market of LED die and driving IC is very different from TFT glass substrate, and TFT glass substrate is also very different from traditional LED display screen using PCB substrate.
That is to say, the PCB substrate, COG and LED chips used in the traditional LED display screen are not "monopoly markets". However, the supply of TFT glass substrates is in a "relative monopoly state". In particular, the production capacity of large-size TFT glass substrates above the eighth generation line has three characteristics: capital-intensive, technology-intensive and capacity-intensive. The global core suppliers are not only few in number, but also giant enterprises.
In other words, at present, the large-scale enterprises involved in the processing of large-size TFT glass substrates are giants with investment scale of hundreds of billions, such as Samsung, LG, Innolux, AUO, BOE, Huaxing Optoelectronics, Hui Ke and Shentianma.
Therefore, in the COG era, TFT glass substrate, as an upstream industrial chain, has an unprecedented "decisive position" in the history of LED display in terms of industry control and pricing power of related LED display products. For example, at the TCL Huaxing Ecological Conference in June 5438+065438+ 10, the display products of mini-led and micro-led based on COG technology at least involved the LED display industry, including "upstream and downstream partners" such as Sanan Optoelectronics, Liard and Jufei Optoelectronics, covering a huge product line from 1. X-inch micro display to 125-inch giant display.
Compared with the number and supply universality of traditional LED wafers and dies, high-precision PCB boards, IC, LED particle packaging and terminal enterprises in the LED display industry, COG technology's TFT glass substrate may have fewer suppliers, stronger monopoly and larger volume: often a TFT glass substrate giant will correspond to multiple LED wafer and die manufacturers and multiple LED downstream terminal enterprises. This pattern is likely to make TFT glass substrate enterprises become the middle connection point of the dumbbell structure of the whole industrial chain on COG products.
Whether COG will change LED display from traditional grid supply chain competition to dumbbell supply chain competition in the future is the most concerned issue in the industry! According to industry insiders, the emergence of the latter may become something that fundamentally changes the competition law of the LED display industry.
TFT glass substrate enterprises show the new leading position of LED display screen.
At the TCL Huaxing DTC202 1 Global Display Ecology Conference held on June 6th 165438, the LED display products displayed by Huaxing Optoelectronics include: 125 inch transparent MiniLED direct display, 75 inch P0.6 oxide AM direct display MiniLED TV, and 1 integrated In-cell touch technology. 7. 1 inch flexible MicroLED screen; And many differentiated products such as 6.24-inch high-brightness MicroLED screen.
Coincidentally, since 2020, companies such as Shentianma and BOE have also exhibited various mini-led, micro-led display products and LED splicing display products based on glass substrates for many times. Samsung and Innolux also demonstrated mini-led and micro-LED glass substrate direct display products based on new colorization technologies such as color conversion films.
Glass substrate+massive transfer +miniled and microLED are new innovative display directions that are equivalent to the technology of organic light-emitting diodes or even exceed the potential of organic light-emitting diodes in the eyes of display panel giants. In these innovations, LED display products for color TV and splicing large screen completely coincide with the "main technology and market attack direction" of traditional small-pitch LED enterprises, and become the leader of LED display frontier technology innovation in recent years.
In the industry's view, no other enterprise in the small and medium-sized display market has the ability to compete with the traditional panel giants in the micro-LED direct display innovation of COG technology. However, in the market of large size, color TV and engineering large screen, in the era of COG LED display, the "market position struggle" between panel enterprises and traditional small-pitch LED display enterprises and LED packaging enterprises has begun. Deepening the upstream cooperation with TFT glass substrate suppliers and panel enterprises is the key for small-pitch LED enterprises to continue to become market C in the future COG era.
From the perspective of traditional LCD and OLED display industries, panel enterprises have mastered both TFT glass substrate products and the structured process flow of functional materials on the substrate-the core workload of display terminals of downstream terminal enterprises is very small, and more is the integration of the whole machine. However, in the traditional small-pitch LED display industry, especially the products using COB technology, small-pitch LED terminal enterprises have mastered the initiative of most industrial links except LED wafers, including the huge transfer process of LED crystal operation. -The latter is equivalent to the "structured process flow of functional materials on the substrate" in the traditional panel industry.
That is, panel enterprises and small-spacing LED enterprises, who master the core process of huge transfer, will have an absolute "final role" in the value status of different enterprises in the future COG era, LED display industry. In other words, if panel companies insist on intervening in huge transfer packaging, the "technical content" industry discourse power of LED display terminal companies may drop to a very low level in COG products.
This possibility shows the "initiative" of panel enterprises and the "passive state of small-spacing LED enterprises" in the COG era. This is also the biggest concern of the LED display industry for COG technology besides "cost and market demand".
To sum up, the impact of COG technology on LED display industry is far greater than any previous technological progress, not only surface mount and COB can not be compared with it, but also the huge transfer technology, miniled and microLED is only a part of the COG framework. The application of COG technology in LED display industry and the launch of TFT glass substrate giants have LED to the possible development of LED display industry pattern to "display panel". These changes require enterprises in the LED display industry not only to attach great importance to technology and product innovation, but also to establish their own cooperation system in the industrial chain ecology as soon as possible.