Is glass substrate the future of Mini/Micro LED
At present, PCB substrate is the mainstream, and glass substrate represents the future, especially when it comes to Micro LED!
Judging whether an industry has prospects, which stage it is in, and the investment and financing situation in the capital market are undoubtedly good indicator. Because of this, the prosperity of the Mini LED industry chain in recent years is an excellent evidence.
According to incomplete statistics, the new investment in Mini/Micro LED and other fields in 2022 will exceed 70 billion RMB . Among them, non-LED industry chain enterprises accounted for more than 40% of the investment. Supporting industrial chains such as equipment and materials have also become one of the key points of investment this year.
Among them, investment in Mini LED substrates is one of the key points this year. Whether it is the current mainstream PCB substrate or the future glass substrate field, there is an investment of more than 1 billion to increase production and expand production.
This momentum will continue until 2023.
Previously, on January 4, Bomin Electronics, a major PCB manufacturer, issued an announcement stating that the company plans to sign an “Investment Agreement” with the Hefei Economic Development Zone Management Committee, and intends to invest in Bomin ceramic liners and IC packaging substrate industries in the Economic Development Zone. The base project, with a total investment of about 5 billion RMB, invests in the construction of a production base for IGBT ceramic liners and IC packaging substrates.
The latest news shows that Lenovo’s P32 pz-30 high-end display released at CES2023 uses BOE’s leading glass-based AM-driven Mini LED technology.
The attitude of the capital market to Mini LED substrates is more direct, and related concept stocks will have a considerable increase in 2022. However, the secret battle between PCB substrate and glass substrate, AM driver and PM driver is becoming more and more “prominent”.
Localization of Mini LED PCB substrate is unstoppable
With the successive entry of Mini LED players, Mini LED direct display has landed in more application scenarios, and Mini backlight has also gained more and more recognition in fields such as TVs, e-sports monitors, notebooks, and vehicles.
Consumer electronics manufacturers such as LED packaging manufacturers, display manufacturers and panel manufacturers have no doubts about the market prospects of Mini LED, but they have their own ideas about the substrate selection of Mini LED. PCB, FPC and glass substrate all have different proponents.
Mini LED has high requirements on the performance of PCB substrates. At present, the products that can meet the requirements basically need to be imported from other countries or Taiwan. This has also led to high PCB substrate prices, and this high cost has also been extended to Mini backlight and direct display products.
In 2022, the situation of relying heavily on imports of PCB substrates used in Mini LEDs has been greatly improved. At present, the PCB substrates used in Mini LED backlights have basically been made in China, while some major manufacturers of Mini LED direct display still use imported PCB substrates.
Dr. Zeng Zhaoming, vice president of Jinko Electronics, said before that there are currently three major trends in terms of PCBs and glass substrates used in Mini LEDs. Trend 1, PCB is still dominated by double-layer FR4, and the quality and supply are relatively stable; Trend 2, the low-cost Mini LED backlight solution uses single-sided aluminum substrates, which can greatly save the cost of PCBs; Trend 3, more glass substrates suppliers and players have entered, but the current cost and maturity have yet to be verified.
According to relevant sources, the most important factor in choosing domestic PCB substrates or imported PCB substrates is the accuracy problem. Even so, the wave of localization of Mini LED PCB substrates has become unstoppable.
Since 2022, Chinese PCB manufacturers have increased their production capacity of Mini LED substrates. Kingshine Electronic, Bomin Electronics, and Ellington Electronics have all raised funds or plan to increase the production capacity of PCB substrates for Mini LED.
Due to the limitation of heat dissipation of the PCB substrate, Mini LED will have more chip soldering per unit area, and the heat density will be higher than the current LED backlight products, and the PCB substrate will have the problem of warping and deformation. Although glass substrates have advantages in terms of cost and other aspects, they also have obvious disadvantages such as hardness and easy cracking, and the yield rate is still relatively low.
Glass substrates are the main trend in the future, but PCB substrates are undoubtedly the first choice under the current technical conditions.
The future of glass substrates
Different from LED companies, panel manufacturers such as BOE and TCL Huaxing, which are more familiar with glass substrate technology, choose to mainly promote glass-based Mini LED products.
On August 30, 2019, TCL CSOT launched the new MLED-Xingyao screen, a large-size AMMini-LED with a glass substrate. TCL Huaxing began to lay out the Mini-LED on TFT backplane in 2018. Compared with the Mini-LED on PCB backplane pushed by the whole machine factory, the display effect is the same, and the cost of TFT driving is reduced.
“Glass substrates are definitely superior to PCB substrates in terms of flatness and stability, and they also have advantages in cost.” A senior person in the industry said. “whether Mini backlights will be used on a large scale in the TV market or in the future for tablets, laptops, etc., panel makers must require glass substrates.”
From a technical point of view, due to the higher requirements of the Mini backlight on the thickness uniformity, flatness, alignment and other processing accuracy of the substrate, the glass substrate will undoubtedly be superior in terms of comprehensive performance and cost in the future. The advantages of ultra-thin glass substrate, heat dissipation, and high-density drive are also very obvious.
At the same time, glass substrates are also highly mature upstream products, especially in ultra-fine and ultra-large boards, and have advantages in scale cost and process cost.
From the cost analysis of the currently high Mini LED TV, in the Mini LED backlight panel, the cost of the substrate accounts for nearly 50%. Substrate cost reduction has become the key to the large-scale application of Mini LED backlight and direct display, and glass substrates have become the “ideal” for panel and TV manufacturers.
Vogel Optoelectronics believes that the low expansion and contraction and high flatness of the glass substrate can better support the real COB packaging of Mini LED chips, and even Micro chip packaging, which are excellent in high-end products, high partitions, narrow borders and low OD values. It has good performance better than PCB substrate.
BOE believes that compared with other solutions, glass-based direct display has four advantages:
1. The AM active drive can realize the perfect fitting of the full-gray-scale Gamma curve, which shows that the display screen of the product has a uniform transition, and the naked eye can still detect subtle changes in brightness without flickering under extremely dark screens.
2. In terms of image quality, the glass-based contrast ratio can reach one million to one, and 115% NTSC ultra-high color gamut can be realized. The product presents clear image quality and high saturation effect.
3. Compared with COB products, the power consumption of glass base is lower, and the overall power consumption can be reduced by 20% under the premise of the same brightness and transmittance.
4. It has higher stability, flatness, no seams and no risk of lamp drop, longer service life, and has outstanding performance in size, heat resistance, and humidity resistance compared with traditional PCB bases.
At the same time, the application of the Mini LED backlight glass substrate can meet the current general demand for thinner thickness and lower power consumption of the whole machine, so it has a wide range of coverage in home entertainment and daily work.
Leading packaging companies in China, including Dongshan Precision, Nationstar, and Jingtai, have not given up their efforts in glass substrate technology while they are currently supplying PCB-based Mini products in batches.
After overcoming the yield rate, the glass backplane has potential advantages in terms of design, production efficiency, and cost. When the higher number of partitions has higher requirements for packaging and higher requirements for circuits, the glass substrate has a better chance to stand out.
Some insiders said that at the stage of Micro LED, the glass substrate can have more room for development by virtue of the advantages of high process precision and small warpage.