Flexible AMOLED leads the display trend, and the market scale expands rapidly. Since the mass production of flexible AMOLED screen and its application in Samsung Galaxy round in 2013, most mobile phone manufacturers began to use flexible AMOLED screen instead of rigid AMOLED screen and LCD screen, so as to increase the proportion of screen and pursue the effect of comprehensive screen. In 2019, folding screen mobile phones will come out, such as Samsung's Galaxy fold and Huawei's mate X. Full screen and curved screen mobile phones have become the mainstream of the market, while folding screen, as an emerging technology in the market, is highly sought after.

The development of flexible AMOLED technology will drive the demand growth of polyimide (PI). In the process of switching from rigid OLED to flexible OLED, some materials can no longer meet the demand of flexibility due to their physical and chemical properties. The inherent brittleness of glass, ITO and other materials makes it difficult to meet a wide range of emerging application scenarios, and switch to PI with better performance. The main changes are as follows:

● Glass substrate switch to PI base plate

● The touch controlled ITO + pet base film is switched to nano silver wire + PI base film

● The glass or metal cover is switched to PI cover. In addition to yellow PI for substrate, CPI is required for touch control and cover plate, which requires high optical properties