• Title/Summary/Keyword: Pixel capacitance

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Simulations of Pixel Characteristics for Large Size and High Qualify TFT-LCD using a new sophisticated Capacitance Formulas (새로운 정전용량 계산식물 이용한 대면적 .고화질 TFT-LCD의 화소 특성 시뮬레이션)

  • 윤영준;정순신;김태형;박재우;최종선
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1999.05a
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    • pp.613-616
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    • 1999
  • An active-matrix LCD using thin film transistors (TFTs)has been widely recognized as having potential for high-quality color flat-panel displays. Pixel-Design Array Simulation Tool (PDAST) was used to profoundly understand the gate signal distortion and pixel charging capability, which are the most critical limiting factors for high-quality TFT-LCDs. Since PDAST can simulate the gate data and pixel voltages of a certain pixel on TFT array at any time and at any location on an array, the effect of the new set of capacitance models on the pixel operations can be effectively analyzed, The set of models which is adopted from VLSI interconnections calculate more precise capacitance. The information obtained from this study could be utilized to design the larger area and finer image quality panel.

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Effects of an Empirical Capacitance Models and Storage Capacitance Types on TFT-LCD Pixel Operations (실험적 정전용량 모델과 축적 용량 설계 방법에 따른 TFT-LCD 화소의 동작 특성)

  • Yun, Young-Jun;Jung, Soon-Shin;Park, Jae-Woo;Choi, Jong-Sun
    • Proceedings of the KIEE Conference
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    • 1999.07d
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    • pp.1750-1752
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    • 1999
  • An active-matrix liquid crystal display (LCD) using thin film transistors (TFTs) has been widely recognized as having potential for high-quality color flat-panel displays. Pixel-Design Array Simulation Tool (PDAST) was used to profoundly understand the gate signal distortion and pixel charging capability, which are the most critical limiting factors for high-quality TFT-LCDs. Since PDAST can simulate the sate, data and pixel voltages of a certain pixel on TFT array at any time and at any location on an array, the effect of the new set of capacitance models on the pixel operations can be effectively analyzed. The set of models which is adopted from VLSI interconnections calculate more precise capacitance. The information obtained from this study could be utilized to design the larger area and finer image quality panel.

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Circuit Design of Fingerprint Authentication for Smart Card Application (스마트카드의 인증을 위한 지문인식 회로 설계)

  • 정승민;김정태
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2003.05a
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    • pp.249-252
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    • 2003
  • This paper propose an advanced circuit for fingerprint sensor signal processing. We increased the voltage between ridge and valley by modifying the parasitic capacitance eliminating circuit of sensor plate. The analog to comparator was designed for comparing the sensor signal voltage with the reference signal voltage. We also propose an exective isolation strategy for removing noise and signal coupling of each sensor pixel. The 128$\times$144 pixel fingerprint sensor circuit was designed and simulated, and the layout was performed.

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Mutual Coupling Capacitance and Cross-talk in TFT-LCD

  • Yun, Young-Jun;Jung, Soon-Shin;Kim, Tae-Hyung;Roh, Won-Yeol;Choi, Jong-Sun
    • 한국정보디스플레이학회:학술대회논문집
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    • 2000.01a
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    • pp.71-72
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    • 2000
  • The design of large area thin film transistor liquid crystal displays (TFT-LCDs) requires consideration of cross-talks between the data lines and pixel electrodes. These limits are imposed by the mutual coupling capacitances present in a pixel. The mutual coupling capacitance causes a pixel voltage error. In this study, semi-empirical model, which is adopted from VLSI interconnection capacitance calculations, is used to calculate mutual coupling capacitances. With calculated mutual coupling capacitances and arbitrary given image pattern, the root mean square (RMS) voltage of pixel is calculated to see vertical cross-talk from the first to the last column. The information obtained this study can be utilized to design the larger area and finer image quality panel.

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Analysis on the Gray Scale Capability of TFT-LCD using Three-dimensional Simulation (3차원적 시뮬레이션에 의한 TFT-LCD의 Gray Scale 성능 분석)

  • Kim, Sun-Woo;Park, Woo-Sang
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.20 no.3
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    • pp.250-256
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    • 2007
  • We analyzed the effect of a pixel and all the inter-electrode capacitances in a unit pixel of TFT-LCDs on the gray scale capability. The pixel and all the inter-electrode parasitic capacitances were obtained from the tree dimensional profiles of potential distribution and molecular director considering lateral fields generated at the edge of the pixel. To obtain the RMS and kickback voltages of the pixel, we constructed an equivalent circuit of the panel containing all the parasitic capacitances. The calculation was performed though H-SPICE. As results, we confirmed that the pixel becomes smaller, the effect of parasitic capacitances on the gray scale capability becomes larger.

Design of a Fingerprint Authentication Sensor with 128${\times}$144 pixel array (128${\times}$144 pixel array 지문인식센서 설계)

  • 정승민;김정태;이문기
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.7 no.6
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    • pp.1297-1303
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    • 2003
  • This paper propose an advanced circuit for fingerprint sensor signal processing. We increased the voltage between ridge and valley by modifying the parasitic capacitance eliminating circuit of sensor plate. The analog comparator was designed for comparing the sensor signal voltage with the reference signal voltage. We also propose an effective isolation strategy for removing noise and signal coupling, ESD of each sensor pixel. The 128${\times}$l44 pixel fingerprint sensor circuit was designed and simulated, and the layout was performed.

A Novel Pixel Structure for High Transmission TFT-LCD

  • Shin, Kyoung-Ju;Song, Se-Young;Lee, Il-Pyung;Kim, Chang-Hoon;Jang, Chang-Soon;Chai, Chong-Chul;Souk, Jun-Hyung
    • 한국정보디스플레이학회:학술대회논문집
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    • 2008.10a
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    • pp.208-210
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    • 2008
  • We have developed a LCD Panel that form storage capacitance for pixels between pixel electrode of bottom glass and common electrode of top glass. This method could make higher transmission and higher production yield than before by removing storage electrode line and capacitance on the bottom glass by simplifying bottom pixel structure.

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Dynamic Pixel Models for a-Si TFT-LCD and Their Implementation in SPICE

  • Wang, In-Soo;Lee, Gi-Chang;Kim, Tae-Hyun;Lee, Won-Jun;Shin, Jang-Kyoo
    • ETRI Journal
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    • v.34 no.4
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    • pp.633-636
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    • 2012
  • A dynamic analysis of an amorphous silicon (a-Si) thin film transistor liquid crystal display (TFT-LCD) pixel is presented using new a-Si TFT and liquid crystal (LC) capacitance models for a Simulation Program with Integrated Circuit Emphasis (SPICE) simulator. This dynamic analysis will be useful when predicting the performance of LCDs. The a-Si TFT model is developed to accurately estimate a-Si TFT characteristics of a bias-dependent gate to source and gate to drain capacitance. Moreover, the LC capacitance model is developed using a simplified diode circuit model. It is possible to accurately predict TFT-LCD characteristics such as flicker phenomena when implementing the proposed simulation model.

Simulations of Capacitive Cross-talk Effects on TFT-LCD Operational Characteristics (TFT-LCD 특성에 미치는 Capacitive Cross-talk의 영향에 대한 시뮬레이션)

  • 윤영준;정순신;김태형;최종선
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1999.11a
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    • pp.557-560
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    • 1999
  • The design of large area thin film transistor liquid crystal displays (TFT-LCDs) requires consideration of cross-talks between the data lines and pixel electrodes. These limits are imposed by the parasitic capacitive elements present in a pixel. The capacitive coupling of the data line signal onto the pixel causes a pixel voltage error. In this study semi-empirical capacitance model which is adopted from VLSI interconnection capacitance calculations was used to calculate mutual coupling capacitances. With calculated mutual coupling capacitances and given image pattern, the root mean square(RMS) voltage of pixel is calculated to see vertical cross-talk from the first to the last column. The information obtained from this study could be utilized to design the larger area and finer image quality panel.

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Writable Cholesteric Liquid Crystal Display and the algorithm used to detect its image

  • Lee, Da-Wei;Shiu, Jyh-Wen;Sha, Yi-An;Chang, Yu-Pei
    • 한국정보디스플레이학회:학술대회논문집
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    • 2007.08a
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    • pp.356-359
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    • 2007
  • Writable Cholesteric Liquid Crystal Display and the algorithm used to detect its image were developed. We could use any hard tip, ex: the tip of a forefinger, to directly write an image on the surface of Cholesteric Liquid Crystal Display (CHLCD). By measuring the capacitance of one pixel of test cell (12mm x 15mm/1x1), F-state or P-state could be detected. By measuring the capacitance of one pixel of 4.1" CHLCD (241um x 241um/ 320x320), F-state or Pstate could not be detected, due to the effect of parasitic capacitance. Therefore, high frequency measurement and the algorithm were developed to detect the image on CHLCD.

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