Introduction of TFT LCD film technology and applications

TFT LCD screen has the dual characteristics of "active" of transistor and "thin" of "film", and combined with flat panel display (such as LCD, OLED, etc.), constitutes today's flat-panel TV (TFT-LCD, TFT-OLED) , TFT is one of the key core components.

TFT LCD screen:

Usually, the active material of TFT is silicon film. According to the structure of silicon film, transistors are divided into amorphous silicon TFT (a-SiTFT), polycrystalline silicon (p-SiTFT) and single crystal silicon MOSFET (c-SiMOSFET). In addition, TFTs prepared with organic materials are called organic TFTs.

TFT technology occupies a core position in the flat panel display industry, with the characteristics of capital-intensive, talent-intensive, and technology-intensive, high panel output value, and obvious industrial agglomeration effect. Although TFT technology is mature, it is still developing rapidly. There is still room to continuously reduce production costs and improve panel performance by improving thin-film materials and fabrication processes.

TFT LCD Thin Film Technology

1. Amorphous silicon film. Amorphous silicon thin film transistor technology was proposed in the 1970s. After nearly 30 years of unremitting efforts by scientists from all over the world, the production lines of liquid crystal display (LCD) of the seventh generation and above have been fully automated, and the industrial production technology is quite mature. It has developed into the mainstream product of liquid crystal display in the world today, and the goal of future development is larger screen size and lower production cost. The advantages of amorphous silicon TFT technology are that the preparation process is mature, relatively simple, and the yield is high, which is suitable for large-area production. The disadvantage is that TFT only has N-type devices, and the mobility is only 0.5-1.0cm2/Vs.

2. Polysilicon film. Polysilicon thin film processes are mainly divided into two categories:

(1) High temperature process, refers to the temperature higher than 900 ℃ in the whole process. The high-temperature process can only use expensive quartz as the substrate, and the TFT has good performance. The high-temperature process is only suitable for small and medium-sized display or projection screen series.

(2) Low temperature process, the temperature during the whole process is lower than 600 ℃. Larger displays can be fabricated on inexpensive glass substrates using low-temperature processes. Low temperature polysilicon (LTPS) TFTs are widely used in active (active) driving display TFT-LCDs and AMOLEDs due to their low power consumption, light weight, thin profile, high current delivery and system integration. The key to the process of polysilicon TFT is how to prepare high-quality polysilicon thin films with low cost and large area.

3. Organic thin film TFT. It is self-evident that the emergence of organic TFT Display will form a strong competition for the existing amorphous silicon TFT. It will be the core technology of a new generation of flexible displays. Displays manufactured using flexible display technology can be rolled like a canvas and may become an important member of the future display world like liquid crystal displays.

Due to the use of organic materials, it has the characteristics of flexible display, so it is not only impact resistant, but also light in weight and small in size. Not only has the appearance of the display been changed, but the application environment has also been greatly expanded and diversified. Printing the display on a sheet of plastic film using a roll-to-roll process similar to newspaper printing can greatly reduce production costs.

Application of TFT LCD screen

1. Portable display: video mobile phone, video PDA, video e-book, etc.;

2. Vehicle display: GPS, safe driving display, multimedia display, etc.;

3. Computer display: laptop, monitor, etc.;

4. Home appliances and office display: TV, Internet terminal, electronic newspaper, etc.