• 한국정보디스플레이학회:학술대회논문집
• /
• 한국정보디스플레이학회 2008년도 International Meeting on Information Display
• /
• pp.228-230
• /
• 2008

The response time characteristic of low voltage liquid crystals (LCs) is investigated and a new simulator for low voltage LCs is proposed. In order to enable low voltage operation, it is important to minimize Vth of LCs and variation of pixel voltage caused by dynamic capacitance operation of LC Display. Because dynamic capacitance variation is much larger for low voltage LC operation compared to that of conventional LC material, it is necessary to make a better model for dynamic capacitance operation. A proposed minimizing Vth of LCs and variation of pixel voltage study results through a new constant charge model improve response characteristics for low voltage LCs operation.

• 한국전기전자재료학회논문지
• /
• 제21권4호
• /
• pp.368-375
• /
• 2008

In this paper, we calculated the pixel and all the inter-electrode capacitances in a unit pixel of three kinds of TFT-LCD modes in order to realize the full color image. And we analyzed the effect on applied voltage. We fixed size of sub-pixel and designed a unit pixel of three kinds of TFT-LCD modes. We calculated rigorously the pixel and all the inter-electrode capacitances by the three dimensional simulation. And we expanded one pixel into whole panel using H-SPICE. As a result, we calculated the RMS voltage and kickback voltage which most affect gray scale of the pixel and calculated the number of bit according to permissible range of minimum gray scale using V-T curve.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2000년도 하계학술대회 논문집
• /
• pp.320-323
• /
• 2000

In the resent years, the Thin Film Transistor Liquid Crystal Display(TFT-LCD) have trend toward larger panel sizes and higher spatial and/or gray-scale resolution. In this trend, Because of its low field effect mobility, a-Si TFT is change to poly-Si TFT. In this paper, both effective-medium model of poly-Si TFTs and empirical capacitance model are applied to Pixel Design Array Simulation Tool (PDAST) and the pixel characteristics of TFT-LCD array were simulated, which were compared with the results calculated by Aim-Spice.

• 대한전기학회논문지:전기물성ㆍ응용부문C
• /
• 제48권6호
• /
• pp.416-428
• /
• 1999

A user-interactive pixel design tool for high-quality TFT-LCDs is realized and used to explore the sensitivity of the various array and device parameters for optimizing pixel design. In this tool, the Thompson cable equation and gradual-channel approximation were used for the gate time delay and TFT current modeling respectively. With this tool, each capacitance element, and TFT and array dimensions can be optimized under given design specifications. The electrical characteristics such ascharging ratio, gate time delay, pixel voltage level-shift, and holding ratio can be analyzed. The sensitivity analysis of those design parameters were executed and presented.

• 센서학회지
• /
• 제28권2호
• /
• pp.133-138
• /
• 2019

The a-InGaZnO (a-IGZO) thin film transistor (TFT) has the advantages of larger mobility than that of amorphous silicon TFTs, acceptable reliability and uniformity over a large area, and low process cost. A capacitive-type touch sensor was studied with an a-IGZO TFT that can be used on the front side of a display due to its transparency. A capacitive sensor detects changes of capacitance between the surface of the finger and the sensor electrode. The capacitance varies according to the distance between the sensor plate and the touching or non-touching of the sensing electrode. A capacitive touch sensor using only one a-IGZO TFT was developed with the reduction of two bus lines, which made it easy to reduce the pixel pitch. The proposed sensor circuit maintained the amplification performance, which was investigated for various drive conditions.

• 한국정보과학회논문지:소프트웨어및응용
• /
• 제36권8호
• /
• pp.616-622
• /
• 2009

동적 커패시턴스 제어(DCC) 기술로 인하여 액정 디스플레이 장치의 약점 중 하나였던 응답 시간 성능이 크게 개선되었다. 하지만 DCC는 계산 과정에서 이전 프레임 영상의 실시간 저장 및 출력을 반복해야 하며, 이 과정에 활용되는 고속 메모리는 HD 고해상도 디스플레이 제작에 있어 높은 하드웨어적 부담 및 비용 상승의 원인이 된다. 본 연구에서는 복잡도가 낮은 고속 영상 압축 기법인 변형 지수-골룸 (MEG) 코딩을 제안하며, 이를 통해 DCC 기술에 요구되는 메모리의 양을 크게 줄일 수 있다. 또한 본 연구에서는 화소별 DCC 스위칭 기법을 제안하여 압축 오차가 최종 액정 디스플레이 영상의 시각 품질에 악영향을 미치지 않도록 하였다. 제안된 방식을 이용해 DCC 처리용 메모리의 크기를 1/3로 줄여도 최종 영상의 시각 품질 손상이 거의 없음을 실험을 통해 확인할 수 있었다.

• 한국정보디스플레이학회:학술대회논문집
• /
• 한국정보디스플레이학회 2002년도 International Meeting on Information Display
• /
• pp.560-562
• /
• 2002

The liquid crystal(LC) pixel capacitance Clc, which varies as a function of applied pixel voltage, is a main factor of pixel voltage errors on input gamma voltage, and therefore of the electro-optics(E-O) characteristics of LC pixel for a-Si TFT LCDs. The pixel voltage error(${\Delta}$Vp) for input gamma voltage was simulated for 14.1 inch diagonal XGA panel. An agreement between the experimental results and simulation was satisfactory for the gamma voltage compensation, ${\Delta}$Vp of the input gamma voltage. The proposed compensation method was successfully introduced to a 14.1 inch diagonal XGA panel, and a remarkable improvement of image sticking was achived.

• 한국정보디스플레이학회:학술대회논문집
• /
• 한국정보디스플레이학회 2005년도 International Meeting on Information Displayvol.II
• /
• pp.936-939
• /
• 2005

• 한국정보디스플레이학회:학술대회논문집
• /
• 한국정보디스플레이학회 2007년도 7th International Meeting on Information Display 제7권2호
• /
• pp.1327-1329
• /
• 2007

We developed a 4 inch (qVGA, 320x240) a-Si TFT LCD which has the function of color scanner. We have designed the novel pixel structure and got good scanning quality with minimum aperture loss. In this new pixel, the sensor capacitance was increased in double without decreasing the aperture loss.

• Journal of Information Display
• /
• 제7권1호
• /
• pp.35-40
• /
• 2006

Organic light-emitting diode (OLED) display panel using the charge-pump (CP) pixel addressing scheme was fabricated, and the results show that it is applicable for information display. A CP-OLED panel with 64 ${\times}$ 64 pixels consisting of thin-film capacitors and amorphous silicon Schottky diodes was fabricated using conventional thin-film processes. The pixel drive circuit passes electrical current into the OLED cell during most of the frame period as in the thin-film transistor (TFT)-based active-matrix (AM) OLED displays. In this study, the panel was operated at a voltage level of below 4 V, and this operation voltage can be reduced by eliminating the overlap capacitance between the column bus line and the common electrode.