With the development of display technology, an oxide thin film transistor has been used widely due to advantages of high electron mobility, low fabrication temperature, and excellent homogeneity.
An organic light emitting diode (OLED) display is a display which emits light by itself. On basis of the driving manner, it can be divided into a passive matrix driving OLED (PMOLED) display and an active matrix driving OLED (AMOLED) display. The AMOLED display has been increasingly applied to various high performance display fields due to advantages of low cost, fast response, power saving, and a large operation temperature range.