• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 하계종합학술대회 논문집(2)
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• pp.257-260
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• 2002

This paper describes the pixel of AMOLED(act ive matrix organic light emitting diode) driving circuit by poly-sl technology. The area per pixel is 278um$\times$278um in 120$\times$160(2.2 inch) Driving the OLEDS with active matrix leads to the lower voltage operation, the lower peak pixel currents and the display with much greater efficiency and brightness The role of the active matrix is to provide a constant current throughout the entire frame time and is eliminating the high currents encountered In the passive matrix approach, This design can support the high resolutions expected by the consumer because the current variation specification is norestricted. The pixel has been designed driving TFT threshold voltage cancellation circuit and wide aperture ratio circuit that communizes 4 pixel. The test simulation results and layout are 11% per threshold-current var Eat ion and 12.5% the aperture ratio of increase.

• 전기전자학회논문지
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• 제18권3호
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• pp.403-408
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• 2014

본 논문은 Varying Interpolator를 개선하여 다수의 Pixel을 한 번에 처리할 수 있는 Rasterizer 구조를 제안한다. 설계한 Rasterizer의 Varying Interpolator는 한 번에 16 Pixel을 처리 할 수 있으며 최대 64개의 색상을 출력으로 가진다. 또한 Rasterizer의 연산을 행렬연산 및 행렬변환으로 구성하여 연산의 중복성을 줄이고 재사용성을 높여 Rasterizer의 처리 속도를 높였다. 제안하는 구조의 Rasterizer 는 기존의 연구와 비교하여 색상 보간은 11%, Rasterizer 전체 처리 속도는 17% 향상된 성능을 보였다.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2003년도 International Meeting on Information Display
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• pp.881-884
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• 2003

We propose a new pixel structure for Active Matrix OLED (AMOLED). The proposed pixel structure can display full color images by compensating threshold voltage (Vth) variation of driving TFTs. And we obtain an improved contrast ratio(C/R) of higher than 600:1

• Computers and Concrete
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• 제33권6호
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• pp.671-688
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• 2024

The modeling efficiency of concrete meso-models close to real concrete is one of the important issues that limit the accuracy of mechanical simulation. In order to improve the modeling efficiency and the closeness of the numerical aggregate shape to the real aggregate, this paper proposes a method for generating a two-dimensional concrete meso-model based on pixel matrix and skeleton theory. First, initial concrete model (a container for placing aggregate) is generated using pixel matrix. Then, the skeleton curve of the residual space that is the model after excluding the existing aggregate is obtained using a thinning algorithm. Finally, the final model is obtained by placing the aggregate according to the curve branching points. Compared with the traditional Monte Carlo placement method, the proposed method greatly reduces the number of overlaps between aggregates by up to 95%, and the placement efficiency does not significantly decrease with increasing aggregate content. The model developed is close to the actual concrete experiments in terms of aggregate gradation, aspect ratio, asymmetry, concavity and convexity, and old-new mortar ratio, cracking form, and stress-strain curve. In addition, the cracking loss process of concrete under uniaxial compression was explained at the mesoscale.

• Journal of Electrical Engineering and Technology
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• 제11권4호
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• pp.1020-1026
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• 2016

Motion estimation (ME) algorithms supporting quarter-pixel accuracy have been recently introduced to retain detailed motion information for high quality of video in the state-of-the-art video compression standard of H.264/AVC. Conventional sub-pixel ME algorithms in the spatial domain are faced with a common problem of computational complexity because of embedded interpolation schemes. This paper proposes a low-complexity sub-pixel motion estimation algorithm in the transform domain utilizing shifting matrix. Simulations are performed to compare the performances of spatial-domain ME algorithms and transform-domain ME algorithms in terms of peak signal-to-noise ratio (PSNR) and the number of bits per frame. Simulation results confirm that the transform-domain approach not only improves the video quality and the compression efficiency, but also remarkably alleviates the computational complexity, compared to the spatial-domain approach.

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

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2002년도 International Meeting on Information Display
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• pp.108-112
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• 2002

A new pixel driving method for organic light-emitting diode (OLED) flat-panel display (FPD) is proposed. The new charge-pump passive-matrix pixel driver consists only of a storage capacitance and a rectifying diode, and no thin-film transistor (TFT) is needed. The new driver not only supplies a constant current to the OLED throughout the whole period of panel scanning like an active-matrix driver, but also provides a highly linear gray-scale control through a pure digital manner.

• JSTS:Journal of Semiconductor Technology and Science
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• 제14권5호
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• pp.594-600
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• 2014

A threshold voltage compensation pixel circuit was developed for active-matrix organic light emitting diodes (AMOLEDs) using amorphous indium-gallium-zinc-oxide thin-film transistors (a-IGZO-TFTs). Oxide TFTs are n-channel TFTs; therefore, we developed a circuit for the n-channel TFT characteristics. The proposed pixel circuit was verified and proved by circuit analysis and circuit simulations. The proposed circuit was able to compensate for the threshold voltage variations of the drive TFT in AMOLEDs. The error rate of the OLED current for a threshold voltage change of 3 V was as low as 1.5%.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1998년도 춘계학술발표회논문집(2)
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• pp.705-710
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• 1998

We describe a multigrid wavelet-based natural pixel (WNP) method for image reconstruction in emission computed tomography (ECT). The ECT is used to identify the tagged radioactive material's position in the body for detection of abnormal tissue such as tumor or cancer, as in SPECT and PET. With ECT methodology in parallel beam mode, we formulate a matrix-based reconstruction method for radionuclide sources in the human body. The resulting matrix for a practical problem is very large and nearly singular. To overcome this ill-conditioning, wavelet transform is considered in this study. Wavelets have inherent de-noising and multiscale resolution properties. Therefore, the multigrid wavelet-based natural pixel (WNP) method is very efficient to reconstruct image from projection data that is noisy and incomplete. We test this multigrid wavelet natural pixel (WNP) reconstruction method with the MCNP generated projection data for diagnosis of the simulated cancerous tumor.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 추계학술대회 논문집 전기물성,응용부문
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• pp.22-23
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• 2006

A new current-driving pixel circuit for active-matrix organic light-emitting diodes (AMOLEDs), composed of four organic thin-film transistors (OTFTs) and one capacitor, is proposed using a current scaling method. Designing pixel circuits with OTFTs has many problems due to the instability of the OTFT parameters with still unknown characteristics of the material. Despite the problems in using OTFTs to drive the pixel circuit, our work could be set as a goal for future OTFT development. The simulation results show enhanced linearity between input data and OLEO luminescence at low current levels as well as successfully compensating the variation of the OTFTs, such as the threshold voltage and mobility.