• The Bulletin of The Korean Astronomical Society
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• v.37 no.2
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• pp.223.1-223.1
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• 2012

우주물체 전자광학 감시체계(OWL: Optical Wide-field Patrol)는 지구상에서 빠르게 이동하는 우주물체를 신속하고 정확하게 관측할 수 있는 광학 감시체계이다. 이 체계의 임무를 완수하기 위한 광학계는 약 2도 이상의 광시야, 충분한 광량 확보를 위해 직경 500 mm 이상의 주반사경(primary mirror), 광학적 능률향상을 위한 25% 이상의 투과율, 운반 및 진동에 의한 영상성능 저하를 보정하기 위한 부반사경 구동기능, 빠른 경통 회전속도에 의한 광학 및 광기구 구조물의 안전성 확보를 위한 작은 F-수 확보 등 주요 요구조건을 만족해야 한다. 본 논문에서는 OWL 광학계의 요구조건을 만족하는 광학계의 광학 및 광기구 설계 등 개발현황을 소개하고자 한다.

• Elastomers and Composites
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• v.44 no.4
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• pp.366-372
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• 2009

The present study covers the optimal design for a lens module in a mobile phone camera by using the design of experiments (DOE) and finite element (FE) analysis. FE analyses are performed to investigate the effect of design parameters on the amount of torque required to assemble a barrel and a housing part. The DOE approach is then performed to optimize the design parameters in order to maintain an appropriate torque with less variations.

• Journal of Korean Ophthalmic Optics Society
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• v.14 no.3
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• pp.29-35
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• 2009

Purpose: To develop a relay lens type scope with 70 mm eye relief. Methods: By using Sigma 2000 design program, we designed and manufactured a relay lens type scope with 70 mm eye relief, which is integrated after designing an objective part with relay lenses and an eyepiece part, respectively. Results: The characteristics of the relay lens type scope with 70 mm eye relief whch is designed and manufactured by methods, which integrate after respectively designing an object part with relay lenses and an eyepiece part, have the magnification of $+4{\times}$,the length from 1st lens to last lens of about 105 mm, the barrel diameter of 18mm, and the effective diameter of 13 mm. Also we know that the resolution line width is 275 cycles/rad at the 30% MTF value criterion. Conclusions: We could design and manufacture the relay type scope with 70 mm eye relief, the characteristics of which have the magnification of $+4.0{\times}$the MTF above 30% at 275 cycles/rad, and the length from 1st lens to last lens of about 105 mm.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.47 no.4
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• pp.309-318
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• 2019

The thermal design of the Lunar Terrain Imager (LUTI) on the Korean Pathfinder Lunar Orbiter (KPLO) was performed and the soundness of the thermal design was verified by thermal analysis. The thermal environment of the lunar mission orbit should be reflected in the thermal design because the IR radiation of the lunar surface is important, unlike the earth orbit. The components or modules exposed to the outside of the satellite are insulated with MLI as much as possible, but the camera tube and the radiator are functionally exposed, so the thermal shield using the concept of radiation shape factor is mounted on the front to mitigate IR radiation. The IR emissivity is important in the front side of the radiator that receives little solar radiation, and components that are susceptible to thermal deformation such as the tube use a radiation heater to minimize the temperature gradient. Through the investigation of computational results, it was confirmed that the thermal design of LUTI is stable in various situations.

• Korean Journal of Optics and Photonics
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• v.32 no.6
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• pp.259-265
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• 2021

Recently, lens manufacturing and assembly technology has greatly improved. However, tight requirements of manufacturing and assembly lead to an increase in cost and manufacturing time, and in some cases the performance of an optical system may deteriorate depending on the operating environment's conditions, such as temperature or vibration. In addition, the use of a compensator is an effective method to reduce sensitivity in an ultra-precision optical system, but in the case of a small lens, such as that in an endoscope, it is difficult to use a compensator due to the size limitation of the lens barrel. Therefore, minimizing lens sensitivity is the most important technology in lens design. For this reason, there have been various attempts to reduce the lens sensitivity, and there is a trend to add functions to reduce the sensitivity in the lens design S/W. In this paper, we introduce a design technology that minimizes lens sensitivity. We first design a lens with quite good performance, then analyze the sensitivity of this lens, make a multi-configuration with high-sensitivity element error, and then reoptimize it. We prove with an example that this design technique is very effective.

• The Bulletin of The Korean Astronomical Society
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• v.39 no.2
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• pp.110.2-110.2
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• 2014

본 연구는 중소기업청 공고 중소기업기술개발 지원사업 과제로 한국천문연구원(주관기관)과 (주)져스텍(공동개발기관)이 공동으로 수행하였다. 지원사업 과제는 출연연과 중소기업이 기술개발 및 이전을 하여 개발된 망원경을 상용화하는 것이 목표이다. 망원경에서 가대부는 (주)져스텍에서, 경통부는 한국천문연구원에서 각각 담당하여 제작 하였다. 시스템을 설계하고 가대부, 경통부, 디로테이터 등을 조립,정렬하였고, 제작품을 시험한 결과, 초기 개발 목표치에 달성 하였다. 망원경을 제작하면서 한국천문연구원에서 가지고 있던 기계부, 전자부, 프로그램에 대한 기술을 (주)져스텍에 이전하여 독자적으로 제작이 가능하게 하였다. 본 과제를 수행하면서 국립 고흥청소년우주체험센터 망원경을 제작하게 되어 가격경쟁력을 갖는 망원경 제작이 가능하다는 것을 입증 하였다. 향후 광학계가 완성되고 원하는 성과를 내면 중형망원경을 개발하는데 많은 도움이 될 것이다.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.105.1-105.1
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• 2013

Schottky Emitter (SE)는 미국 FEI의 L. W. Swanson 그룹이 개발하여 상용화시킨 전자원이며, 고분해능 전자현미경용 전자원 시장에서 가장 큰 점유율을 차지하고 있다. 상온에서 작동하는 cold field emitter (CFE)에 비해 휘도(brightness)가 10~100배 정도 낮으나, 10-10 Torr 영역의 초고진공에서도 수시간 미만의 방출전류 안정성을 가진 CFE에 비해 수개월이상 안정된 방출전류를 전자현미경에 제공하므로, 반도체 측정, 검사 등과 같이 고분해능과 안정성이 동시에 요구되는 분야에서는 SE전자원은 필수 요소가 되어있다. 현재 SE 전자원은 일본, 미국, 영국의 4개사가 과점하고 있는 상태이다. SE 전자원이 안정되게 작동하기 위해서는 10~10 Torr 영역의 초고진공 환경이 요구된다. 한국 전자현미경 업체는 국책과제 등을 통해 SE 전자총을 개발해 왔으나, 진공기술과 광학계 설계기술이 부족하여 안정된 SE 전자총의 개발에 성공하지 못하였다. 본 발표에서는 10~10 Torr 영역에서 200 microA 이상의 전류를 안정되게 방출하는 SE 전자총의 전자빔 방출 및 진공특성을 보고한다. 시뮬레이션을 통해 구한 전차총의 전자원 위치 변화, 건렌즈 초점거리, 수차 등의 광학특성을 보여준다. 전자총을 전자현미경 경통에 탑재하고 제어하기 위해서는 전자총뿐만 아니라 전자현미경 전체의 광학특성을 이해할 필요가 있다. 전자총을 현미경에 통합 제어하기 위한 기술과제에 대해서도 간략히 보고한다.

• Korean Journal of Remote Sensing
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• v.34 no.2_1
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• pp.227-236
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• 2018

The focus control mechanism of the multi-purpose camera can be required for the better quality image acquisition. A good image acquisition through the hardware system including the optics and image sensor, has to be processed before the post correction for improvement of image quality. In the case of the high-resolution satellite camera, the focus control is not a necessity, unlike a normal camera due to a fixed optical system, but may be required due to various reasons. Although there is a basic focus control method using a motor for satellite electronic optical camera, a focus control method using thermal control can be a good alternative because of its various advantages in design, installation, operation, contamination, high reliability and etc. In this paper, we describe the design method and implementation results for the focus control mechanism using the temperature sensor and heater installed in the telescope structure. In the proposed focus control method, the measured temperature information is converted into temperature data by the Kalman filter and the converted temperature data are used in PI controller for the thermal focus control.

• Journal of Korean Ophthalmic Optics Society
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• v.17 no.4
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• pp.441-447
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• 2012

Purpose: This paper is about development and design of the 1x optical path relay adapter for the beam splitting prism by us the day & night scope. Methods: To product the day & night scope by using the beam splitting prism and the commercial zoom optical system with the C-mount lens barrel structure, the optical path relay adapter, which doesn't change the image size of the zoom optical system and can stretch the position of the image-forming surface, is needed. We could design the 1x optical path relay adapter by using the CodeV program in which the Lens Module mode is offered. Results: We could design the optical path relay adapter used in the day&night scope with the beam splitting prism, of which characteristics have the EFL of -56.0 mm, the magnification of +1.0x, the distance from the 1st lens surface to the last lens surface of about 20.4 mm. The resolution of this system is characterized by 30 lp/mm at 40% MTF. This is enough to accommodate the designed optical path relay adapter can overcome the resolution of the 3rd generation of image intesifier tubes. Conclusions: By designing and applying the optical path relay adapter of which optical characteristics have the EFL of -56.0 mm, the magnification of +1.0x, the distance from the 1st lens surface to the last lens surface of about 20.4 mm, and the resolution of 30 lp/mm at 40% MTF, we could develop the new type day&night scope consisting of the beam splitting, the commercial zoom optical system with the C-mount lens barrel structure, and the 3rd generation of image intesifier tubes.

• Journal of Korean Ophthalmic Optics Society
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• v.13 no.2
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• pp.23-28
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• 2008

Purpose: To develop the 2~8X zoom beam expander for the 1064 nm laser source. Methods: After developing the program by which the initial design values of 3-component zoom tracks can be quickly obtaind, we design and develop the zoom beam expander by applying this program and the commercial program of Sigma 2000. Results: In this study, we could develop the program by which the initial design values of zoom tracks can be quickly obtaind, and by applying this program and the commercial program of Sigma 2000 we could design and develop the zoom beam expander for 1064 nm which is able to zoom from 2${\times}$ to 8${\times}$. The developed zoom beam expander has an efficient diameter of the incidence side of 8 mm, an efficient diameter of the exit side of 32 mm, and a capacity with the finite ray aberration within 0.0001rad. Because the overall length (OAL) is restricted between 125 mm and 135 mm, the change of the whole barrel length which is caused by variations of the zoom driving becomes to be within 10 mm. Conclusions: we could develop the program by which the initial design values of zoom tracks can be quickly obtaind, and by applying this program we could design and develop the zoom beam expander for 1064 nm which is able to zoom from 2${\times}$ to 8${\times}$.