• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.275-275
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• 2009

CdTe(331)/Si(211) and CdTe(400)/Si(100) thin films have been grown by MOCVD(metal organic chemical vapor deposition) system for large scale of IFPAs(IR focal plane arrays). We have investigated the effect of various growth parameters on the surface morphology and structural quality. Single crystalline CdTe(331) films were grown by two stage growth method - low temperature buffer layer step and high temperature growth step. In other case, single crystal of CdTe(400) films were grown on a few atomic layer thickness of GaAs which is grown on Si(100) substrate by molecular beam epitaxy. The crystalline quality of the films was analyzed by X-ray diffraction. The surface morphology and crystal structure of CdTe films were characterized by optical microscope.

• Proceedings of the Materials Research Society of Korea Conference
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• 2003.11a
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• pp.207-207
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• 2003

Uncooled infrared(IR) detectors that use a microbolometer with a large focal-plane array(FPA) have been developed with surface micromachining technology. There are many materials for microbolometers, such as metals, vanadium oxide, semiconductors and superconductors. Among theses, vanadium oxide is a promising material for uncooled microbolometers due to it high temperature coefficient of resistance(TCR) at room temperature. It is, however, is very difficult to deposit vanadium oxide thin films having a high TCR and low resistance because of the process limits in microbolometer fabrication. In general, vanadium oxides have been applied to microbolometer in mixed phases formed by ion beam deposition methods at low temperature with TCR in the range from -1.5 to -2.0%K.

• Proceedings of the KIEE Conference
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• 2006.10c
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• pp.582-584
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• 2006

This paper describes a monocular PSD-based motion capture sensor to employ with commercial video game systems such as Microsoft's XBOX and Sony's Playstation II. The system compact, low-cost, and only requires a one-time calibration at the factory. The system includes a PSD(Position Sensitive Detector) and active infrared (IR) LED markers that are placed on the object to be tracked. The PSD sensor is placed in the focal plane of a wide-angle lens. The micro-controller calculates the 3D position of the markers using only the measured intensity and 2D position on the PSD. A series of experiments were performed to evaluate the performance of our prototype system. From the experimental results we see that the proposed system's compact size, low-cost, ease of installation, and high frame rates are suitable for high speed motion tracking in games.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.4
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• pp.343-346
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• 2010

We have investigated growth of CdTe thin films by using (As, GaAs) buffer layers for application of large scale IR focal plane arrays(IFPAs). Buffer layers were grown by molecular beam epitaxy(MBE), which reduced the lattice mismatch of CdTe/Si and prevented native oxide on Si substrates. CdTe thin films were grown by metal organic chemical deposition system(MOCVD). As a result, polycrystalline CdTe films were grown on Si(100) and arsenic coated-Si(100) substrate. In other case, single crystalline CdTe(400) thin film was grown on GaAs coated-Si(100) substrate. Moreover, we observed hillock structure and mirror like surface on the (400) orientated epitaxial CdTe thin film.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.1043-1044
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• 2008

In this study, a novel algorithm of the improvement residual non-uniformity (RNU) in thermal imaging system is proposed using correlated double sample signal processing. The proposed method attempts to eliminate offset variation of ROIC in IR detector causing the variation of FPA (focal plane array) temperature and suppling power. Experimental results show that the proposed method confirmed a better performance than the existing RNU system.

• Journal of Sensor Science and Technology
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• v.10 no.5
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• pp.337-342
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• 2001

Infrared sensors with one or two dimensional arrays are usually bonded via indium bumps to Si CMOS read out circuits. Therefore, both sensing of infrared beams and processing of signals are performed at the focal plane. This gives us a benefit of reducing noise as well as size of infrared detectors. We have developed a way of boding indium bumps with keeping sensor and ROIC parallel to each other. The flip chip bonder developed has a very simple structure and is easy to operate. So we expect that reliability will be improved very much.

• Korean Journal of Optics and Photonics
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• v.18 no.2
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• pp.135-141
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• 2007

This paper describes the design technology for a third generation thermal imaging system, which is more compact than before, using a $320\times240$ mid-IR focal plane detector. The third generation non-scanning thermal imaging system was constructed as a compact thermal imaging module as a reconnaissance, surveillance and navigation sensor for helicopter and infantry vehicles in the $1980's\sim1990's$ and now, we designed a new compact infrared camera and studied a new type of non-uniformity correction lens fer this camera.

• Korean Journal of Optics and Photonics
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• v.10 no.6
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• pp.462-467
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• 1999

This paper describes the design and fabrication of mid-IR $(3.7-4.8{\mu}m)$ zoom optics which is used for FUR (Forward Looking Infra-Red) system with 320 $\times$ 240 focal plane arrays. The zoom optics has 20 magnification range and maximun 40$^{\circ}$$\times$30$^{\circ}$ of super wide field of view. The locus of zoom is almost linear, which gives easy access of mechanical and electro-mechanical design. The on-axis MTF of zoom optics has been measured and it shows diffraction limited optical performance. For example, it gives 0.692 at 24 cycles/mm at highest magnification, and 7.6 cycles/mradof resolving power is achieved with the operation of attached micro-scanning system.system.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.39 no.11
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• pp.7-13
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• 2002

BSCT 320${\times}$240 IRFPA detector module is implemented, which is a key component in uncooled thermal imaging systems. The detector module consists of two parts, infrared sensitive pixel array and read-out integrated circuit(ROIC). The BSCT 320${\times}$240 pixels are made by laser scribe process and 10-${\mu}m$ micro-bump to satisfy 50-${\mu}m$ pitch and 95-% fill-factor. The ROIC has been designed to electrically address the pixels sequentailly and to improve signal-to-noise ratio with single transistor amplifier, HPF, tunable LPF and clamp circuit. The fabricated hybrid chip of detector and ROIC has been mounted on the TEC built-in ceramic package for more stable operation and tested for lots of electrical and optical properties. The IRFA sample has shown successful properties and met with good results of fill-factor, detectivity and responsivity.

• The Bulletin of The Korean Astronomical Society
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• v.35 no.1
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• pp.40.1-40.1
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• 2010

The Main payload of the STSAT-3 (Korea Science & Technology Satellite-3), MIRIS (Multipurpose Infra-Red Imaging System) has been developed for last 3 years by KASI, and its Flight Model (FM) is now being developed as the final stage. All optical lenses and the opto-mechanical components of the FM have been completely fabricated with slight modifications that have been made to some components based on the Engineering Qualification Model (EQM) performances. The components of the telescope have been assembled and the test results show its optical performances are acceptable for required specifications in visual wavelength (@633 nm) at room temperature. The ensuing focal plane integration and focus test will be made soon using the vacuum chamber. The MIRIS mechanical structure of the EQM has been modified to develop FM according to the performance and environment test results. The filter-wheel module in the cryostat was newly designed with Finite Element Analysis (FEM) in order to compensate for the vibration stress in the launching conditions. Surface finishing of all components were also modified to implement the thermal model for the passive cooling technique. The FM electronics design has been completed for final fabrication process. Some minor modifications of the electronics boards were made based on EQM test performances. The ground calibration tests of MIRIS FM will be made with the science grade Teledyne PICNIC IR-array.