High-speed driving and pixel nonuniformity compensation method for active-matrix OLED display = 능동 매트릭스 OLED 디스플레이를 위한 고속 구동 및 화소간 불균일성 보상 방법

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In this thesis, pixel nonuniformity compensation method and high-speed driving method are introduced to overcome two main obstacles of AMOLED display driving: temporal and spatial variation of TFT, and data-line RC delay. In Chapter 1, an active matrix organic light emitting diode (AMOLED) display driver IC, enabling real-time TFT non-uniformity compensation, is presented with a hybrid driving method to satisfy fast driving speed, high TFT current accuracy and a high aperture ratio. The proposed hybrid column driver IC drives a mobile UHD (3840x2160) AMOLED panel, with one horizontal time of 7.7$\mu$s at a scan frequency of 60Hz, and simultaneously senses the TFT current for back-end TFT variation compensation. Thanks to external compensation, a simple 3T1C pixel circuit is employed in each pixel. Accurate current sensing and high panel noise immunity is guaranteed by a proposed current sensing circuit. By reusing the hybrid column driver circuitries, the driver embodies an 8-bit current-mode ADC to measure OLED V-I transfer characteristic for OLED luminance degradation compensation. Measurement results show that the hybrid driving method reduces the maximum current error between two emulated TFTs with a 60mV threshold voltage difference under 1 gray-level error of 0.94 gray-level (37nA) in 8-bit gray scales from 12.82 gray-level (501nA). The circuit-reused current-mode ADC achieves 0.56LSB DNL and 0.75LSB INL. Chapter 2 presents a load-aware pre-emphasis column driver for large-size and high-resolution flat panel displays. The column driver self-calibrates a pre-emphasis factor (K) in a column-parallel fashion to achieve fast driving speed under column-to-column panel-load RC variation. A manufactured prototype IC of the column driver drives panel load of 3.87k$\Omega$ and 150.6pF within 1.8$\mu$s, which is a 1-H time of UHD (3840x2160) display at a scan frequency of 240Hz, with less than 0.7% error under $\pm$18% panel RC variation.
Advisors
Cho, Gyu Hyeongresearcher조규형researcher
Description
한국과학기술원 :전기및전자공학부,
Publisher
한국과학기술원
Issue Date
2017
Identifier
325007
Language
eng
Description

학위논문(박사) - 한국과학기술원 : 전기및전자공학부, 2017.8,[iv, 57 p. :]

Keywords

amoled▼adata driver▼ahybrid driver▼athreshold voltage shift▼aoled degradation▼acircuit-reused current-mode adc▼aoffset-compensated integrating comparator▼athin-flim transistor▼apre-emphasis driving▼aload-aware pre-emphasis driving; 유기발광디스플레이▼a데이터 구동 회로▼a하이브리드 구동 회로▼a문턱 전압 변이▼aOLED 열화▼a회로-재사용 전류모드 ADC▼a오프셋보상 적분 비교기▼a박막 트랜지스터▼a선강조 구동▼a부하 측정 선강조 구동

URI
http://hdl.handle.net/10203/242070
Link
http://library.kaist.ac.kr/search/detail/view.do?bibCtrlNo=718933&flag=dissertation
Appears in Collection
EE-Theses_Ph.D.(박사논문)
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