Research On The Performance Of Active Matrix Organic Light Emitting Diode Driving Circuit Based On Low Temperature Poly-silicon Thin Film Transistor Technology

Organic light-emitting display(OLED)is emerging application for the flat panel displays due to various advantages such as high luminance,Simple,wide viewing angle,fast response time,self-luminous characteristic.Therefore OLED is widely employed in vehicles,tablet,industrial control,medical application,wear and other fields,and has been hailed as the next generation display technology after the LCD(liquid crystal display)technology.OLED is current driving device,its brightness is generally proportional to the current,In this paper,based on the development of OLED,we analyzed the different structures of OLED,and described the working principles.According to the OLED addressing method,we classified OLED as passive matrix organic light emitting diode(PMOLED)and active matrix organic light emitting diode(AMOLED),PMOLED exists some drawbacks such as line resistance effect,slow response speed,large power consumption,therefore PMOLED driving technology is not suitable for high resolution displays.This paper focuses on the analysis of the application and working principle of AMOLED driving technology,because the merits of AMOLED driving technology such as lower power consumption and high resolution,independent control.According to the channel material of the TFT,AMOLED driving circuit can be classified into three categories: amorphous Silicon thin film transistor(a-Si TFT),low temperature poly-crystalline Silicon thin film transistor type(LTPS TFT)and oxide thin film transistor.the electrical characteristics of them are described in this paper.SILVACO software is used to simulate the current changes caused by a-Si TFT and LTPS TFT threshold voltage drift 3V in the 2T1 C circuit,And the influence of capacitance and TFT W/L ratio on the OLED current in the circuit is simulated and analyzed.A novel 5T1C(PMOS p-Si TFT)drive compensation circuit is designed.The working principle of the initialization phase,data reading phase and luminescence phase is analyzed,and its TFT threshold voltage drift compensation function is proved theoretically.Comparing 5T1 C with 2T1C(a-Si TFT),it is found that the current stability of 5T1 C circuit is better than that of 2T1 C circuit under the same condition.