The preparation of AMOLED on a flexible substrate to achieve flexible display is considered to be an important direction for the development of display technology. However, as far as the current conditions are concerned, the flexible display is still facing many challenges, including how to prepare thin-film transistors with high performance and high reliability at low temperatures, how to prepare flexible electrodes, etc., as well as thin film encapsulation technology (TFE). mature. Since AMOLED is sensitive to water vapor in the air, the existence of water vapor is the main factor affecting the life of AMOLED devices. Therefore, the output of thin film packaging has practical significance for the practical application of flexible AMOLED. Through the improvement of equipment and technology, breaking through the technical difficulties has become one of the most concerned topics in the industry.
The importance of flexible display is further highlighted
In terms of market competition this year, LCD TVs seem to have advantages over AMOLED TVs. In addition to cost and price factors, new technologies in TFT-LCDs are emerging, such as quantum dot technology (wider through the use of quantum dots). The LED backlight is re-emitted in the frequency range to achieve a more vivid picture quality. The LCD TV screen has a color gamut comparable to that of the AMOLED TV; the contrast of the LCD TV screen is constantly increasing, and the full array backlight can be flexibly localized. Dark backlight, giving night or other dark images in darker black.
Affected by this, people are now focusing more on flexible display on the development of AMOLED technology. "The flexible display capability of AMOLED is incomparable to TFT-LCD. Compared to the fragility of glass, the substrate used in flexible AMOLED is plastic or foil, which essentially eliminates the problem of fragile glass and gives end products to manufacturers. In addition, the ultra-thin plastic or foil display substrate makes the OLED display device ultra-thin and light-weight, making products such as mobile phones and wall-mounted TVs smaller and lighter. Xiao Jinsong, vice president and general manager of the company's CVD product division, pointed out.
Thin film package solves the problem of AMOLED lifetime
However, in terms of current technological conditions, flexible AMOLED devices have made great progress in terms of material lifetime, driving, brightness, colorization and flexibility, but the industrialization process still lags behind, mainly due to the longevity of the device and its high The efficiency problem has not been completely solved.
In this regard, Xiao Jinsong believes: "The important challenge for AMOLED is to reduce the penetration of water vapor and oxygen into the device. Because most plastic substrates do not have enough capacity to adequately block the intrusion of external impurity liquids and gases, the metal used in OLED devices. The cathode is generally an active metal such as aluminum, magnesium, calcium, etc., and it is very easy to react with the infiltrated water vapor, which affects the injection of electric charge. In addition, the infiltrated water and oxygen also react with the organic material, and these reactions cause the device. The performance is degraded. Compared with the properties of glass, the commercially available plastic substrate material is not ideal for the isolation of water vapor and oxygen and the protection against aging of the device, and cannot meet the commercial display for more than 10,000 hours of continuous operation under video brightness. Lifetime requirements. In addition, the flatness of a plastic substrate is usually worse than that of a glass substrate, and protrusions on the surface of the substrate may cause defects in the film structure and damage the device. Moreover, most of the flexible substrates have a low melting point even if At lower temperatures, plastics are also unstable in size, making it difficult to accurately align groups The multilayer structure of the OLED device. Therefore, the study can block the moisture and oxygen and packaging technology comparable to the height of the glass material, to improve the efficiency of the device, to extend the life of the device is important. "
At present, AMOLED packaging technology generally includes metalCAN packaging technology, Glass packaging technology, thin film packaging technology and Hybrid packaging technology. Among them, thin film packaging technology not only attracts attention in the field of large-size AMOLEDs that appeal to light and thin, but is also known as the next generation. Display technology is a must-have technology in the field of soft OLED and OLED lighting. Promoting the maturity of thin film packaging technology, it plays an important role in improving the yield, reducing cost and extending the life of the device.
Xiao Jinsong further pointed out: "Relatively speaking, non-flexible OLED display devices can use materials such as glass cover plates, and only need to use a thin film package at the edge of the device, but the flexible display can not be processed in this way, mass production of thin film packaging technology. Development is even more meaningful."