脈衝寬度調變式信號主動矩陣有機發光二極體驅動電路

Abstract

由於手持式消費性產品對低功耗、體積小及重量輕的需求提高，因此， OLED顯示器漸漸取代TN/STN LCD。主動矩陣之OLED驅動路無論是功耗或效能都比被動矩陣電路更勝一籌。因此，更省電、體積小、提高均勻度及使用壽命更久的AMOLED電路最佳化設計，便成為時下研發單位重要的課題。 一般而言，許多改善電路都會為了提高OLED的效能(如使用壽命、均勻度及彈性)，而增加一至數條控制線來控制傳統OLED驅動電路。然而，額外的OLED信號線卻為造成製程難度及成本。因此，解決這些缺點並同時提高OLED顯示器的效能成為主要的研究課題。本論文研製了脈衝寬度調變式信號主動矩陣有機發光二極體驅動電路。就目前所知PWM訊號驅動電路，是目前較受歡迎的數位驅動方式。反應時間短的OLED脈衝寬度驅動方法解決了現今TFT-LCD的動態模糊缺陷。因此，本論文之新型PWM驅動技術不只減少一半的控制信號，同時與傳統PWM驅動方法也減少驅動IC一半的控制腳位。除此之外，本電路還可以增加OLED元件的使用壽命，並更加精確的控制灰階。 實驗結果證明，本新式PWM驅動技術的可行性。而我們使用中華映管公司的製程，並且以測試模組驗證本電路的功用及效能。未來，我們將能使用本論文所提出的PWM驅動技術，設計一個大尺吋、高均勻度、低成本、及使用壽命長的OLED顯示器。

Owing to increasing requirements of hand held 3C products, low power consumption, small volume, and light weight; OLED is drifting towards displacement of TN/STN LCD. Active matrix OLED driving circuits surpass passive matrix OLED ones not only in power consumption but also in efficiency. Thus, optimum designs of AMOLED driving circuits for achieving low power consumption, small volume, high uniformity, and long life time, are important topics for today’s display market. Generally speaking, several advanced driving circuits add one or more control lines to enhance the performance of OLED like extending life time, uniformity, and flexibility compared to conventional OLED driving circuits. However, the additional control lines for driving OLED increase manufacture difficulties and cost. The challenge of diving circuits is to suppress these disadvantages and enhance the performance of OLED display. This thesis proposed a novel pulse width modulation (PWM) scheme for driving AMOLED. As we know, PWM techniques are most popular driving circuits of nowadays due to digital driving methods. Pulse width driving method with high response time of OLED solves motion blur effects, which are disadvantages of today’s TFT LCD. Therefore, this novel PWM driving technique not only decreased half of control lines but also half control pins of driver IC compare to conventional PWM methods. Furthermore, it can increase the life time of OLED material and accurately enhance control gray levels. Experiment results prove the feasibility of this novel PWM driving technique. We taped out the test key by CPT for demonstrating the function and performance. In the future, we can use the concept proposed by our PWM driving technique to design a large size OLED panel to achieve a high uniformity, low cost, and long life-time OLED display.