具可調變電流畫素電路於非晶矽薄膜電晶體主動式矩陣有機發光二極體顯示器之實現

Abstract

主動式有機發光二極體顯示器電流源畫素電路之缺點，在於顯示低灰階畫面時充電時間過長導致驅動資料的錯誤。本論文藉由與傳統電流源及電流鏡畫素電路之電性比較，證實可調變電流畫素電路的確能有效補償TFT特性的變化並且縮短充電時間，更進一步設計具可調變電流畫素電路的AMOLED面板，解析度為50 × 50，同時並設計所需之驅動電路。在系統整合方面，我們使用FPGA產生信號，經過驅動系統提供可調變電流畫素電路所需之電壓或電流控制信號。最後成功點亮AMOLED面板，並可呈現出八個灰階，另外其發光的亮度亦符合可調變電流畫素電路之特性，顯示此電路設計的確可以達到有機發光二極體顯示器高解析、大尺寸之需求。

The difficulty that current driven pixel circuit of active matrix organic light emitting diode devices encounters lies in long charging time resulted in data programming error while displaying low gray level images. In this thesis, by comparing the adaptive current scaling pixel circuit with conventional current driven pixel circuit and current mirror pixel circuit, the adaptive current scaling pixel circuit is demonstrated to be able to effectively compensate the threshold voltage variation and improve the charging time. Therefore, the adaptive current scaling pixel circuit is designed and applied to AMOLED panel. The OLED devices are deposited on the active area with 50 × 50 pixel array. Moreover, the driving circuits are designed and fabricated. For the integration of system, the driving signals are generated by FPGA. By passing through the driving circuit system, the driving signals are transferred to suitable voltage/current level values for adaptive current scaling pixel circuit. As result, the AMOLED panel is turned on successfully. Such an AMOLED can display 8 gray scales and the experiment results have achieved with the characteristics of adaptive current scaling pixel circuit. These results indicate that the adaptive current scaling pixel circuit can fulfill the requirement of high resolution and large size AMOLED displays.