• 한국정보디스플레이학회:학술대회논문집
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• 2005.07a
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• pp.436-436
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• 2005

We have investigated electro-optical properties of an in-plane switching cholesteric liquid crystal display (LCD). Planar and focal-conic texture changes re induced by application of an in-plane electric field.

• Proceedings of the KSRS Conference
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• 1999.11a
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• pp.349-354
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• 1999

Electro-Optical Camera (EOC) is the main payload of the KOMPSAT-1 satellite to perform the mission of cartography that builds up a digital map of Korean territory including a digital terrain elevation map. This paper discusses the issues of the digital image simulation of EOC for the generation of EOC simulated scene as taken by EOC at 685km altitude on orbit. For the purpose, simulation work has been performed with the sensor models of EOC and the satellite platform motions models through image chain analysis from the illumination source (Sun) to a simulated image output in digital number. MODTRAN fur radiance calculation, MTF models of optics, detector and motions of EOC for system point spread function (PSF), and signal chain equations for digital number output are described. Several noise models of EOC are also considered. The final output is the EOC simulated image in digital number. The simulation technique can be used in several phase of a spaceborne electro-optical system development project, feasibility study phase, design, manufacturing, test phases, ground image processing phases, and so on.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.796-799
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• 2006

We studied the nematic liquid crystal (NLC) alignment capability by the Ion beam (IB) alignment method on a NDLC (Nitrogen doped Diamond Like Carbon) as a C:H thin film, and investigated electro-optical (EO) performances of the IB aligned In plane switching (IPS) 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 good electro-optical characteristics of the IB aligned IPS cell was observed with oblique IB exposure on the NDLC as a-C:H thin film for 1min.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.11a
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• pp.289-290
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• 2005

We have investigated the electro-optical (EO) performances of the flexible liquid crystal display (LCD) on twisted nematic (TN) mode according to variation of cell gap in comparison with glass LCD. There were four kinds of cells which were having cell gaps of 3$\mu$m, 4$\mu$m and 5$\mu$m, especially the lowest 2$\mu$m on flexible and glass substrates separately. The EO performances of the flexible cells on the rubbed potyimide (PI) were almost the same those of glass cells. The response time of flexible cells was shorter than that of glass cells but the alignment of liquid crystal (LC) of flexible cells was weaker than that of glass cells. The residual DC of flexible cells was on the increase like that of glass cells in compliance with lowering cell gap.

• Journal of Sensor Science and Technology
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• v.7 no.1
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• pp.23-30
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• 1998

In this paper, we analyzed the effect of the time delay of the image sensor in the tracking loop of Electro-Optical Tracking System(EOTS). we showed that Smith predictor can greatly improve the stability and various performances of EOTS with time delay. And also, to verify the realistic validity, we executed the experiment in EOTS recently developed, and confirmed the effectiveness in EOTS.

• Bulletin of the Korean Chemical Society
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• v.29 no.4
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• pp.731-735
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• 2008

The fluid ensemble in the liquid lens, which is composed of electrolyte and silicone oil, is the key material system to vary the focal length processing of the electrochemical desorption. In order to characterize the capability of the liquid lens according to response time and optical range, we prepared a fluid ensemble comprising the electrolyte and oil. To elucidate the physical mechanism of the effective response time, we examined the viscosity dependency while satisfying the requirements for the density and refractive index of the electrolyte and oil, respectively. The characterization results indicated that the response time (up and down) is influenced by the viscosity of the electrolyte and oil. On this basis, we prepared a fluid ensemble capable of reversibly adjusting for the focal length of the liquid lens, as well as the response time. The ensemble is applicable to various systems such as micro-lens and optical sensors.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.48 no.5
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• pp.1-7
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• 2011

EOTS(Electro-Optical Tracking System) provides stabilized images while tracking a moving target. The key of geo-pointing is the function that fixes EOTS's sight to a specific position(geo-point) throughout aircraft maneuvers. In this paper, a major error source for the geo-pointing is identified as the transport delay of navigation information, and an augmented Kalman filter is designed to estimate the present attitude of aircraft using delayed navigation information. Simulation results including the presented scheme shows that the error due to the information transport delay reduces under half.

• Macromolecular Research
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• v.12 no.3
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• pp.251-257
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• 2004

The nature of the nematic liquid crystal (LC) alignment induced by the rubbed polyimide (PI) alignment layers (ALs) and the electro-optical (EO) properties of the LC cells are expected to depend on the chemical and physical features of the PI. By employing five pyromellitic dianhydride (PMDA)-type PIs having different functionalities, we have studied the effects of the PI's structure and chemistry on the alignment characteristics and the cell's EO properties. Increasing the flexibility of the PI increases the pretilt angle and tends to improve the alignment stability. On the other hand, the rigid, fluorinated PI displays poor stability for LCs and induces a less stable/uniform LC alignment and, subsequently, a small pre tilt angle. It also transpired that fluorination of the PI deteriorated the voltage-transmittance characteristics and the voltage holding ratio; increasing the flexibility of the PI structure improves these EO properties. The finding that the qualitative trends for the PI's functionalities are similar for both the alignment and EO properties suggests that the EO properties are closely related to the alignment characteristics, which are determined by short-range interactions between LC and PI molecules.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.37 no.3
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• pp.240-247
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• 2009

Wind tunnel test for Electro-Optical Targeting System(EOTS) has been conducted to investigate the aerodynamic characteristics, especially the torque characteristics of the rotating parts to insure the enough actuator power during the actual operation. The influence of EOTS's complex configuration, such as the observation window, has been investigated by comparing with the results of the simplified models made of half sphere and the cylinder. It has been found that the position of the observation window of EOTS has an effect on surface pressure distribution and the torque characteristics of the rotating observation part.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.433-433
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• 2007

In this paper, we investigated the feasibility of applying ZnO:Al films to display devices as transparent electrodes, and reported the electro-optical (EO) characteristics of VA cells using ZnO:Al electrodes and compared them with those of VA cells using ITO electrodes. The experiment results show that a uniform vertical LC alignment and a large pretilt angle were achieved. Also, the good voltage-transmittance curve, response time, and capacitance-voltage characteristics were observed for the rubbing aligned VA-LCD using ZnO:Al electrodes m comparison with ITO electrodes. In other words, the vertical alignment mode based on the ZnO:Al electrodes showed appropriate electro-optical characteristics and high transparency in comparison with that based on the ITO electrodes. These results indicated that the transparent ZnO:Al electrodes of the liquid crystal displays could substitute the ITO electrodes.