• Journal of the Institute of Electronics Engineers of Korea SD
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• v.41 no.9
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• pp.49-56
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• 2004

A new readout circuit(ROIC) for linear HgCdTe 64${\times}$2 two-color Infrared (IR) detector is described. This circuit is based on the buffered direct injection(BDI) technology with high injection efficiency. By using saturation current isolation circuit, the proposed ROIC removed the problems that LWIR(Long Wavelength InfraRed) signal distort when MWIR(Middle Wavelength InfraRed) signal saturates so that new ROIC has larger measurable temperature range about 120k than that of previous circuit and it is also tolerant for dead pixel in MWIR detector. The designed circuit was fabricated using 0.6um 2-poly 3-metal CMOS process. We measured that the designed circuit outputs MWIR signal and LWIR signal simultaneously and saturation current isolationcircuit also operates well. Next, measured noise was about 53uV at room temperature and it can be assumed that designed circuit can satisfy nearly 95% BLIP condition at 77K.

• The Optical Journal
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• s.113
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• pp.54-56
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• 2008

• Journal of the Korea Institute of Military Science and Technology
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• v.21 no.3
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• pp.306-314
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• 2018

In maritime environment, it is necessary to understand the characteristics of sunglint since it may degrade the target detection performance of the infrared sensor mounted weapons. In this paper, sunglint in LWIR band is modeled using the slope distribution of the sea surface, and is verified by comparing the radiance of a simulated result with that of the real world. According to the simulation, sunglint is critical when the solar zenith angle is over $60^{\circ}$. The peak radiance of sunglint grows as the solar zenith angle increases until it reaches $83^{\circ}$ and has a large difference depending on the solar zenith angle when the wind speed is small. Finally, seasonal and temporal characteristics of sunglint effects are analyzed. In summer, sunglint is dominant in the horizon near the solar azimuth right after sunrise and before sunset. However, in winter, the influence of sunglint lasts even during the daytime since the elevation of the sun is much lower than in summer.

• Korean Journal of Optics and Photonics
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• v.34 no.3
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• pp.106-116
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• 2023

In this paper, we designed a coaxial dual camera incorporating two optical systems-one for the visible rays and the other for far-infrared ones-with the aim of capturing images in both wavelength ranges. The far-infrared system, which uses an uncooled detector, has a sensor array of 640×480 pixels. The visible ray system has 1,945×1,097 pixels. The coaxial dual optical system was designed using a hot mirror beam splitter to minimize heat transfer caused by infrared rays in the visible ray optical system. The optimization process revealed that the final version of the dual camera system reached more than 90% of the fusion performance between two separate images from dual systems. Multiple rigorous testing processes confirmed that the coaxial dual camera we designed demonstrates meaningful design efficiency and improved image conformity degree compared to existing dual cameras.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.22 no.5
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• pp.93-97
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• 2022

Infrared scenes usually contain also spectral information which cannot be resolved using normal single-band infrared cameras. Multispectral infrared imaging cameras give access to the comprehensive information contained within infrared scenes. A Dual-band infrared Camera, a type of multispectral infrared imaging cameras, has the advantage of simple system. A Dual-band Infrared Camera gives access to the spectral information as wells as the temperature information within infrared scenes. Multispectral imaging generally increases the detection and identification performance of a Dual-band Infrared Camera. This paper describes a design of an infrared Camera using a Dual-band Infrared Detector to simultaneously receive infrared radiation from the medium-wave infrared/long-wave infrared(MWIR/LWIR) bands.

• Electronics and Telecommunications Trends
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• v.24 no.6
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• pp.99-109
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• 2009

현재 주목을 받고 있는 테라헤르츠 대역의 주파수를 이용한 무선통신시스템 응용기술 동향에 대하여 기술한다. 테라헤르츠 대역은 전자파 스펙트럼에서 밀리미터파 대역과 원적외선 대역의 중간에 위치하는 100GHz~10THz 사이의 주파수이다. 현재 시점에서 10년 이내에 약 15Gbps의 데이터 속도가 필요할 것으로 판단되며, 10Gbps 이상의 전송속도를 실현하기 위해서는 기존의 밀리미터파에서 사용하는 주파수 대역폭 보다 더 넓은 대역폭이 필요하며, 이 대역폭을 얻기 위해서는 테라헤르츠 주파수 대역으로 자연적으로 옮겨가지 않을 수 없다. 본 고에서는 테라헤르츠 대역의 전파 특성, 가용 주파수 대역과 무선통신시스템 응용을 위한 옥내 채널 모델, 테라헤르츠 무선통신시스템 연구동향, RF 송수신기 핵심부품 및 MMIC 기술개발 동향을 소개하고자 한다.

• Korean Journal of Optics and Photonics
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• v.28 no.5
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• pp.241-249
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• 2017

This paper presents the design and evaluation of the optical system for an uncooled thermal-imaging camera. The operating wavelength range of this system is from $7.7{\mu}m$ to $12.8{\mu}m$. Through optimization, we have obtained a LWIR (Long Wave Infrared) optical system with a focal length of 5.44 mm, which consists of four aspheric surfaces and two diffractive surfaces. The f-number of the optical system is F/1.2, and its field of view is $90^{\circ}{\times}67.5^{\circ}$. The hybrid lens was used to balance the higher-order aberrations, and its diffraction properties were evaluated by scalar diffraction theory. We calculated the polychromatic integrated diffraction efficiency, and the MTF drop generated by background noise. We have evaluated the thermal compensation of a LWIR fixed optical system, which is optically passively athermalized to maintain MTF performance in the focal depth. In conclusion, these design results are useful for an uncooled thermal-imaging camera.

• Proceedings of the Optical Society of Korea Conference
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• 2000.02a
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• pp.20-21
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• 2000

헤르츠가 최초로 무선통신의 가능성을 보인 이후 인류는 수 킬로헤르츠 (kHz)의 주파수를 이용하기 시작하여 메가헤르츠 (MHz) 대역에서 라디오, 텔레비젼, 음성 통신 등의 엄청난 기술적 발전으로 문명에 기여해 왔다. 이 MHz 대역이 포화하기 시작하자 더 높은 주파수의 기술을 연구하여 개인 휴대통신, 위성통신 등에 기가헤르츠 (GHz) 대역을 활용하였다. 반면에 빛이라 불리는 매우 높은 주파수의 전자기파는 뢴트겐이 X-ray를 투시 촬영기에 이용한 이래 광통신 등이 발명되어 가시광선에서 적외선까지 더 낮은 주파수 쪽으로 발전·활용되어 왔다. 이러한 광파와 마이크로 전자기파 사이의 테라헤르츠 (THz)주파수 대역 (또는 원적외선 영역 혹은 T-ray라 불림)은 많은 잠재적인 응용분야에도 불구하고 용이한 신호원의 부재로 기초적인 연구도 미비한 상태이다 (그림1 참조). (중략)

• Proceedings of the Optical Society of Korea Conference
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• 1999.08a
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• pp.62-63
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• 1999

• Korean Journal of Optics and Photonics
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• v.9 no.3
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• pp.134-141
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• 1998

A high performance afocal zoom telescope has been designed to operate in the 7.6${\mu}{\textrm}{m}$ to 10.3${\mu}{\textrm}{m}$ waveband for thermal imaging system. This IR zoom telescope is characterized by using of two movable optical element groups, variator and compensator, with mechanically compensated method and the positioning of these groups is controlled by means of a computerized program. The optical performance over the entire 4:1 zoom range and $\pm$2.31~$\pm$9.36 degrees field of view is near diffraction limit while maintaining a constant F-number. The all refracting surfaces of this system except only one aspheric surface are spherical curvature and the material for the optical elements is selected Ge and ZnSe which is used for correction of chromatic aberration.