有機半導體發光元件衰減偵測電路特性研究

The Measurement of Degradation in Organic Light Emitting Displays for Aging Compensation

簡敬倫(Ching-Lun Chien)

指導教授 ： 楊恆隆

國立臺北科技大學/機電學院/光電工程系所/碩士(2006年)

摘要

本論文主題在於研究與設計偵測電路以外部偵測的概念探討有機發光二極體經過長時間的操作後所產生亮度衰減的特性。偵測電路是以有機發光二極體元件亮度衰減時跨壓上升的事實為依據而進行研究與設計。研究結果顯示有機發光二極體元件亮度衰減後跨壓上升值可經由類比式或數位式偵測電路來達成外部偵測的目的。類比偵測電路在模擬過程中是針對電阻的精確度對於偵測電壓能力的影響，其電阻最大誤差值為4%以內，其輸出結果在可接受範圍5%之內，在實際電路驗證方面，當有機發光二極體元件其衰減電壓大於0.1V以上，偵測電壓的誤差範圍約在3~5%之間。數位偵測電路在模擬過程中只能知道偵測動作是否正確，在實際電路驗證方面，因為其偵測能力受限於ADC0804的解析度，當有機發光二極體元件其衰減電壓大於0.1V以上，其誤差範圍約在4%左右。無論是類比式或數位式偵測電路，在誤差範圍內，皆可正確偵測到元件跨壓值變化的結果。

關鍵字

有機發光二極體元件 ； 衰減 ； 外部偵測電路 ； FPGA

並列摘要

This thesis research is to investigate and design the detection circuits based on the concept of external detection to detect the characteristics of luminance decay occurred frequently in organic light-emitting devices (OLED) after long-term operation. The study and design of external detection circuits is based on the fact that the voltage drop across an OLED will gradually increase while degraded. The study results showed that the detection of the voltage-drop increment across an OLED could be achieved by either analog or digital external circuit. The simulation study of the analog detection circuit was focused on the capability of detecting the voltage while affected by the accuracy of resistance values. The percentage error of its output result was acceptable within 5% as the maximum percentage error of resistance value was within 4%. The experimental verification of the analog detection circuit revealed that the percentage error of detected voltage drop was 3~5% while the OLED degraded voltage-drop increment was above 0.1volt. The simulation study of the digital detection circuit was focused on whether the logical motions were correct. The experimental verification of the digital detection circuit revealed that the percentage error of detected voltage drop was about 4%, due to the limitation and resolution of ADC0804, while the OLED degraded voltage-drop increment was above 0.1volt. These external detection circuits, whatever digital or analog design, can accurately detect the variation of voltage-drop across an OLED within reasonable percentage error.

並列關鍵字

Organic Semiconductor Device ； Degrade ； FPGA ； external detect

參考文獻

[2] Shuang Fang Lim, "Degradation of organic light-emitting devices due to formation and growth of dark spots", Materials Science and Engineering, B85, 2001, pp. 154-159.

[3] Zoran D. Popovic, "Reliability and Degradation of Small Molecule-Based Organic Light-Emitting Devices (OLEDs) ", IEEE, vol. 8, no. 2, 2002.

[4] Dechun Zou, "Study on the degradation mechanism of organic light-emitting diodes(OLEDs) ", Synthetic Metals, vol. 91, 1997, pp.191-193.

[7] F. Li, J. Feng, S. Liu, "Degradation of organic light-emitting devices under different driving model", Synth.Met., vol. 137, 2003, pp. 1103-1104.

[8] C. Y. Kwonga, Materials Science and Engineering B, vol. 116, 2005, pp. 75-81.