主動式有機發光二極體顯示器畫素電路是由薄膜電晶體與電容所組成，由於製程上的差異使得元件的特性造成變異，如薄膜電晶體臨界電壓的漂移，導致驅動有機發光二極體的電流產生變化，造成面板亮度的不一致性。除此之外，有機發光二極體的老化所造成跨壓上升與發光亮度下降的現象亦會影響面板顯示品質。而開口率的大小亦決定發光的效率，使用上發光方式的架構因不受畫素內元件數目的限制，故比起下發光方式具有較高之開口率。
本論文針對上述問題提出三個新式畫素補償電路，除了改善面板亮度的不一致性，更利用上發光方式提高畫素開口率。第一個電路架構為4T1C畫素補償電路，此電路能夠補償薄膜電晶體元件特性的變異，且不受OLED 老化所影響，但訊號線過於複雜，製作不易。第二個補償電路亦為4T1C架構，利用簡單的控制訊號線，達到補償薄膜電晶體元件特性變異的效果。第三個電路架構採用外部補償電路機制，在畫素內維持3T1C架構，降低了製作的成本，並利用外部的補償電路補償薄膜電晶體與有機發光二極體元件的變異所造成亮度下降的情形。本論文提出的三個電路，均能改善顯示器因材料變異所導致不均勻的現象，亦提高畫素的開口率，增進發光效率，具有其應用價值。

The pixel circuit of an active matrix organic light-emitting diode (AMOLED) is composed of a capacitor and thin-film transistors (TFTs). As a result of different
fabrication processes, components characteristics such as TFT threshold voltage shift and OLED degradation will vary, indicating that an increase in OLED threshold voltage leads to non-uniformity luminance in panels. Additionally, aperture ratio also influences emitting
efficiency. Therefore, this study adopts a top emission structure to improve the aperture ratio and maintain uniform brightness.
This work proposes three novel pixel circuits to overcome problems associated with threshold voltage shift and OLED degradation. The first pixel circuit with 4T1C compensates for TFT threshold voltage variations and OLED degradation; however this circuit has complex control signal lines. The second circuit, composed of 4T1C, simplifies the control signals and effectively maintains uniform brightness. The third circuit with few elements in the pixel circuit reduces fabrication cost and compensates for material
variations via an external driving circuit. The proposed circuits improve brightness non-uniformity and enhance emitting efficiency. These circuits will contribute to
AMOLED applications in the future.

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