• Journal of the Optical Society of Korea
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• v.16 no.4
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• pp.409-413
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• 2012

Off-axis color shift in the dark state and gray scale inversion in an in-plane switching (IPS) liquid crystal display (LCD) device were investigated. Analyses were performed using the Poincar$\acute{e}$ sphere representation. The results show that color shift in the dark state and gray scale inversion in an IPS LCD can be reduced by using a biaxial film. We confirmed the extent of these improvements by measuring the optical performance of a fabricated IPS LCD.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.07a
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• pp.520-521
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• 2005

To observe the orientation of carbon nanotubes (CNTs) dispersed in nematic liquid crystal (NLC), CNT-doped homogeneously-aligned NLC cells driven by in-plane field was fabricated. The CNTs were aligned with a LC director in the initial state, whereas the CNTs disturbed the LC director above critical ac field. We observed motional textures in the form of vertical stripes in the local area between electrodes, which were associated with a deformation of the LC director orientation. This suggests that CNTs start to vibrate three dimensionally with translational motion. The hysteresis studies of voltage-dependent transmittance under dc electric field show that the amount of residual dc is greatly reduced due to ion trapping by CNT.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.2
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• pp.639-643
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• 2018

As electronic systems become smaller and more portable, the need for power conversion continues to increase. In addition, system stability must be ensured from switching noise due to power conversion efficiency and power conversion system miniaturization. Therefore, countermeasures to reduce switching noise during power conversion are essential. In this paper, a DC/DC buck converter circuit is constructed, and the characteristics of switching noise generated when changing the parts layout in a four-layer printed circuit board (PCB) structure with a reference plane are compared and analyzed. In addition, switching noise characteristics were compared and analyzed through simulations when the parts layout was different in a two-layer PCB structure from which the reference planes were removed. As a result, it was confirmed that the radiated emissions characteristic is reduced by 12dB and the conducted emissions characteristic decreased by 7dB to 8dB, according to the current return path in the four-layer PCB structure. Thus, it was confirmed that the noise characteristics can be improved according to the configuration of the current return path when the power conversion circuit is designed.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.629-632
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• 2009

We have proposed a novel viewing angle controllable display of in-plane switching (IPS) mode with single panel. One pixel of this device is divided to two regions, in which main pixel shows image and sub pixel for viewing angle control. In initial state, the liquid crystal of sub pixel is homogeneous aligned on substrate for wide viewing angle mode. On the other hand, after applying voltage, the liquid crystal of sub pixel tilts up for narrow viewing angle mode. The proposed device has advantage for the function for simple manufacturing process and good viewing angle control with single panel.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.308-309
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• 2008

We have proposed a high performance liquid crystal display using two thin film transistors (TFTs) for the large size TFT-LCD desirably 42inch WXGA panel for TVs. The device generates stronger electric fields to reorient liquid crystals than that in the conventional IPS device because the voltages with opposite polarity with respect to the common electrode are applied to each finger-type electrode. As a result, the operation voltage of 2Tr-IPS mode can be decreased and the transmittance can be increased compared to conventional IPS device. Consequently, the 2Tr-IPS has all the advantages over conventional IPS from large size point of view.

• Journal of Drive and Control
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• v.18 no.3
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• pp.16-22
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• 2021

The variable structure controller has the characteristic that while in sliding mode, the system moves along the switching plane in the vicinity of the switching plane, so it is robust to the parameter fluctuations of the plant. However, a controller based on a variable structure may not meet the desired performance when it is commanded to track any input or exposed to disturbances. To solve this problem, a sliding mode controller based on the IVSC approach excluding an integrator is proposed in this study. The proposed sliding mode control was applied to the position control of a hydraulic cylinder piston. The sliding plane was determined by the pole placement and the control input was designed to ensure the existence of the sliding mode. The feasibility of the modeling and controller was reviewed by comparing it with a conventional proportional control through computer simulation using MATLAB software and experiment in the presence of significant plant parameter fluctuations and disturbances.

• Journal of KIISE:Computing Practices and Letters
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• v.14 no.3
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• pp.311-315
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• 2008

The switching fabric used to make high speed switching for packet transfer between input and output interface in recent internet environments. Without making any changes in order to remain ATM switching fabric, the existing structures should split/reassemble a packet to certain size, set aside cross-point buffer and will put loads on the system. In this paper, we proposed a new switch architecture, which has separated data memory plane and switching plane packet data will be stored on the separate memory structure and simultaneously only the part of the memory address pointers can pass the switching fabric. The small mini packets which have address pointer and basic information would be passed through the switching fabric. It is possible to achieve the remarkable switching performance than other switch fabrics with contending variable length packets.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.05a
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• pp.572-575
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• 2005

A novel pneumatic artificial muscle actuator (PAM actuator), which has achieved increased popularity to provide the advantages such as high strength and high power/weight ratio, low cost, compactness, ease of maintenance, cleanliness, readily available and cheap power source, inherent safety and mobility assistance to humans performing tasks, has been regarded during the recent decades as an interesting alternative to hydraulic and electric actuators. In order to realize satisfactory control performance, a variable damper Magneto Rheological Brake (MRB), Is equipped to the Joint of the manipulator. Superb mixture of conventional PID controller and a phase plane switching control method brings us a novel controller. This proposed controller is appropriate for a kind of plants with nonlinearity, uncertainties and disturbances. The experiments were carried out in practical PAM manipulator and the effectiveness of the proposed control algorithm was demonstrated through experiments, which had proved that the stability of the manipulator can be improved greatly in a high gain control by using MRB with phase plane switching control method and without regard for the changes of external inertia loads.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.04a
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• pp.64-65
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• 2006

We studied the nematic liquid crystal (NLC) alignment capability by the IB(on bean) alignment method on a NDLC(Nitrogen Diamond Like Carbon) as a-C:H thin film, and investigated electro-optical performances of the IB aligned IPS(In plane switching}cell with NDLC surface. A good LC alignment by IB exposure on a NDLC surface was achieved. Monodomain alignment of the IB aligned IPS cell can be observed. The goodelectro-optical (EO) characteristics of the IB aligned IPS cell was observed with oblique IB exposure on the NDLC as a-C:H thin film for 1 min.

• Transactions on Electrical and Electronic Materials
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• v.4 no.1
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• pp.24-28
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• 2003

We have studied the influence of rubbing angles with respect to in-plane field direction on electro-optic characteristics of in-plane switching (IPS) liquid crystal display. The results show that the threshold voltage increases and the operational voltage decreases as the rubbing angle increases. Further, the total response time and also response times associated with grey-to-grey transitions become fast as the rubbing angle decreases.