As the cornerstone of the thin-film display industry, substrate glass is not only widely used in the structure of liquid crystal panels, but also an indispensable base material for OLED. The importance of substrate glass is limited by changes in the display mechanism and is irreplaceable.
The development process of the panel production line towards high generation and high profit margins also determines the same development trend of the substrate glass production line. At present, the international substrate glass giants have long shifted their focus to the construction of large-size, LTPS and OLED substrate glass. However, domestic enterprises have been subject to many restrictions in the process of transformation and development, and have not succeeded in breaking through. Now, this situation has finally changed.
The market is still in a golden development period in the next 5 years
In recent years, terminal display market demand has continued to grow, which has driven the continuous expansion of the flat panel display industry. According to CCID think tank data, global display panel shipment area will reach 266 million square meters this year, with an average annual growth rate of 4%. In particular, the strong growth in demand for large-size panels has driven the global average LCD TV panel size to increase by about 1.3 inches, and the shipment area reached 162 million square meters.
According to data from Qunzhi Consulting, there are currently 16 G8.5+ panel production lines built and under construction in China, of which 14 production lines have been mass-produced. It is expected that in 2021, after all production lines are completed and put into production, G8.5+ high-generation panels will account for more than 80% of the total domestic panel production capacity.
As an essential base material in the industry, the significance of substrate glass to the liquid crystal panel industry is equivalent to that of silicon wafers to the semiconductor industry. Its cost accounts for about 20% of the raw materials of the entire LCD panel. The quality of the substrate glass directly affects the performance and quality of the liquid crystal panel. The light transmittance, thickness, weight, viewing angle and other indicators of the finished panel are closely related to the substrate glass used.
It is reported that as the global display panel shipment area continues to grow, substrate glass, as a key upstream basic material, is expected to grow by 8% in 2020. Among them, the demand for G8.5+ high-generation line substrate glass from China will reach 250 million square meters. Industry experts said that in the next five years, my country's substrate glass market is still in a golden period of development.
"Faced with the booming market, the substrate glass industry is ushering in unprecedented development opportunities. However, compared with display panels, the overall development level of substrate glass in China is relatively lagging. Especially large-size substrate glass and low-temperature polysilicon (LTPS) substrate glass Waiting, has always been a weakness." Dr. Geng Yi from CCID Think Tank Institute of Integrated Circuits told reporters.
Successfully broke through, large-size substrate glass hot end has been mass-produced
The substrate glass industry is a technology-intensive and capital-intensive industry. Although some Chinese manufacturers have mastered the float and overflow process and are able to mass produce substrate glass of G6 and below sizes, in terms of the production of large-size substrate glass of G8.5 and above, domestic companies only have cold-end processing capabilities.
In terms of hot-end furnaces, due to the complex manufacturing process and high technical threshold, the core technology is only mastered by a few countries, and the localized manufacturing capacity is weak. This has always been the weakness of domestic substrate glass manufacturers.
At present, several foreign manufacturers such as Corning of the United States, AGC of Japan, and NEG of Japan have occupied nearly all market shares. Achieving a breakthrough on large-size substrate glass has always been the industry's hope.
A few days ago, Chinese manufacturer HFCH finally broke through the core technology. The first G8.5+ overflow method hot-end substrate glass production line in China has been mass-produced, laying the foundation for the large-scale development of China's large-size substrate glass industry.
Regarding the main difficulties encountered in the R&D and production process, the relevant person in charge of the HFCH LCD Glass Technology Group said in an interview with the reporter of "China Electronics News" that first, the technical difficulties, the products require good chemical stability, low thermal expansion coefficient, High strain point and low defect density, technically require the realization of large flow, low defect, ultra-thin wide plate width and high flatness; the second is the process challenge, in order to ensure the equipment under long-term, high-temperature, multi-phase conditions Reliability and stability pose brand-new challenges to related processes; the third is the lack of materials, and the key materials of the hot end of foreign companies have been tightly sealed.
"The production of large-size substrate glass is indeed very difficult." Xu Zheng, a professor at Beijing Jiaotong University, said in an interview with China Electronics News. Although G8.5 has doubled the area of G6, the number of micro-defects on a single glass The requirements remain unchanged, the defect density requirements are greatly reduced, and the process is more difficult to achieve. In addition, the thickness uniformity and flatness requirements of large-size substrate glass remain unchanged, and the precision of control is more demanding.
Aiming at new areas and speeding up the transition to LTPS/OLED substrate glass
Although large-size liquid crystal substrate glass is ushering in vigorous development, Chinese substrate glass companies have not stopped there. Today, they have begun to focus on the field of OLED panels.
According to HIS Markit's forecast, OLED panel shipments in 2020 will increase by 50% to 4.5 million, and by 2021, shipments will reach 6.7 million. The demand for substrate glass for OLED displays in China will reach 40 million square meters, accounting for about 10% of China's total demand for substrate glass, and it is gradually increasing, and there is a lot of room for demand in the future.
"For Chinese domestic manufacturers, LTPS substrate glass can be used as OLED carrier glass. It is an important breakthrough in line with the development trend of new displays and provides strong upstream material support for the current hot OLED panel manufacturing." Hu Chunming, secretary general of the LCD branch, said Said in an interview with a reporter from China Electronics News.
Like large-size substrate glass, the complete production technology of LTPS substrate glass has long been monopolized by American and Japanese companies. All LTPS substrate glass required by domestic panel companies has been imported.
Recently, the "G6 (G5.5 compatible) LTPS substrate glass development and industrialization project" successfully completed by the Chinese manufacturer DX Glass Technology Group won the first prize of the Anhui Science and Technology Progress Award. At present, the production line of this project has realized the production of quality products and quickly received the first batch of orders.
It is reported that HFCH has also laid out the LTPS/OLED substrate glass industry, and related mass production technologies have been verified online.
"The heat treatment temperature of the crystallization process of LTPS devices is higher than that of TFT-LCD, so the heat shrinkage rate and flatness of the substrate glass are higher." Hu Chunming believes that the performance characteristics of LTPS glass products need to be implemented from the following two aspects Technological breakthroughs: First, joint research and development of key high-temperature resistant equipment and materials; second, optimized design and improvement of LTPS equipment and processes.
"It is expected that rigid OLED substrate glass will be the first to complete industrialization, and flexible OLED substrate glass needs further product certification before it can gradually enter the supply channel." Liu Tun, a senior analyst at CCID Consulting, said in an interview with a reporter from China Electronics News. The main performance requirements of rigid OLED substrate glass are similar to those of TFT-LCD glass substrates. According to the OLED backplane manufacturing process, it needs to be able to meet the normal use in the temperature range of 550°C to 600°C. In addition to being able to work in high-temperature environments, the flexible OLED substrate glass must ensure a high, uniform UV light transmittance within the chip, and meet the needs of separating the flexible substrate from the substrate glass using laser lift-off technology.
“For China’s domestic substrate glass companies, the lack of high-margin high-end products and fierce price competition for low-end products have a greater impact on business operations.” Geng Yi said that in order to improve business conditions and maintain healthy corporate development, domestic Glass substrate companies should further increase investment in technology research and development of new products, and accelerate the pace and speed of transformation and upgrading.
In this regard, Xu Zheng said that at present, the OLED panel production line is mainly based on the 6th generation and below. And the small and medium-sized liquid crystal substrate glass production line of the 6th generation and below can be transformed into an OLED substrate glass or glass cover production line to continue production, which is conducive to the integrated utilization of the production line. Moreover, while saving investment costs, enterprises also shorten the transformation time.