• Journal of Korean Ophthalmic Optics Society
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• v.14 no.4
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• pp.39-44
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• 2009

Purpose: To design a mini optical system photographing the iris, which is used in the iridology. Methods: We designed a mini optical system photographing the iris by using the Sigma 2000 design program. Results: We designed a mini optical system photographing the iris, which is suitable in the CCD using a micro actuator for auto-focusing, of which characteristics have the TCL of 30 mm, a magnification of -0.65, about 8.0 mm distance from the 1st lens to the last lens, the max barrel diameter of 11 mm, and about 1 mm of the effective stop diameter. Also the resolution line width of this system is characterised by 92 lps/mm at the 30% MTF value criterion. Conclusions: By designing an optical system of which characteristics have the TCL of 30 mm, about 8.0 mm distance from the 1st lens to the last lens, the max barrel diameter of 11 mm, and the resolution line width of $5.4{\mu}m$ at the 30% MTF value criterion, we could miniaturize the iris photographing optical system.

• Korean Journal of Optics and Photonics
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• v.26 no.2
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• pp.88-97
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• 2015

An omnidirectional optical system can be described as a special optical system that images in real time a panoramic image with an azimuthal angle of $360^{\circ}$ and the altitude angle corresponding to the upper and lower fields of view from the horizon line. In this paper, for easy fabrication and compact size, we designed and fabricated a catadioptric omnidirectional optical system consisting of the mirror part of a spherical mirror with a central hole (that is, obscuration), a plane mirror, the imaging lens part of 3 single spherical lenses, and a spherical doublet in the visible light spectrum. We evaluated its image performance by measuring the cut-off spatial frequency using automobile license plates, and the vertical field of view using an ISO 12233 chart. We achieved a catadioptric omnidirectional optical system with vertical field of view from $+53^{\circ}$ to $-17^{\circ}$ and an azimuthal angle of $360^{\circ}$. This optical system cleaniy imaged letters on a car's front license plate at the object distance of 3 meters, which corresponds to a cut-off spatial frequency of 135 lp/mm.

• The Optical Journal
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• v.13 no.2 s.72
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• pp.17-22
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• 2001

1995년과 2000년 한국광학회지 수록 논문을 분석해 본 결과 새로운 세부분야가 많이 생기고 기존분야는 더욱 전문화$\cdot$구체회되며 실용성 있는 연구가 많아졌다. 국내에서 기술 수요가 크고 연구비 지원이 많이 이루어지는 광통신기술 분야 연구 논문이 가장 많이 발표되고 있으며 앞으로도 급격히 팽창할 것으로 전망된다. 광학계 설계는 꾸준히 연구가 이루어지고 있어 수요가 지속적으로 있음을 알 수 있다. 광학계 평가도 크게 증가되고

• Proceedings of the Optical Society of Korea Conference
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• 2000.08a
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• pp.50-51
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• 2000

최근에 결상광학계는 광학유리를 사용한 전통적인 단순 구면형에서 플라스틱, 금속 등의 소재와 비구면 혹은 홀로그래피 광학소자를 이용한 복합적 기능형으로 발전하고 있다. 또한 엑스선에서 적외선까지 매우 넓은 분광영역에서 현미경으로 관찰할 수 있는 미소광학소자부터 구경 10 m 정도의 대구경 망원경까지 다양한 크기의 초정밀 결상광학계가 계속 개발되고 있다. 즉 구경 100 mm 정도의 구면 광학계에서 광대역 분광영역의 대구경 비구면 광학계로 발전하고 있다.$^{(1)}$ (표 1 참조) (중략)

• Korean Journal of Optics and Photonics
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• v.17 no.3
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• pp.240-247
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• 2006

This paper discusses the optical system design for projection TV using LCOS type micro display, which provides the high resolution, slim depth, and a large screen of more than 60 inches. We analyzed the relationship between the illumination system, projection lens, color separation & recombination system, and micro display. From this quantitative analysis, the starting data for the optimum light engine was defined, and all optical systems were designed by an optimization process. Three RGB panels were proposed for a high luminence system, and the four prisms symmetrically located make equal optical path lengths for the RGB rays. This color separation & recombination system enables the a compact illumination system. Also, in order to the slim light engine with high resolution, the folded projection lens system was designed by inserting a mirror between projection lenses.

• 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.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1993.04b
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• pp.192-197
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• 1993

반도체 기억소자의 급격한 발전추세에 대응하기 위해서는 노광(exposure) 장비의 증첩정밀도 (overlay accuracy)가 같이 개선되어야 한다. 본 연구에서는 64M ERAM 제조를 목적으로개발된 스텝 퍼(stepper) 시스템의 성능평가 항목 중에서 증첩정밀도에대한 측정방법 및 현재까지의 연구결과를 기술하였다. 제작된 웨이퍼 정렬계는 off-axis 및 TTL 광학계와 이들 정렬신호에 따라 움직이는 웨이 퍼 구동계로 구성되어 있다. off-axis 광학계는 화상처리와 회절의 두 가지 방식이 가능하도록 설계 제작되었으며, TTL 광학계는 dual beam interferometric method를 이용하였다. 본 실험의 결과는 웨이퍼 정렬계의 특성을 평가한 것으로서, 현재까지 off-axis 정렬 방법만으로 얻은 증첩정밀도는 0.26-0.29$\mu$m (m+3 $\sigma$ )이다. 따라서 여기에 이미 제작되어 있는 TLL 정렬광학계를 추가로 사용하면 0.1 $\mu$m 이하의 정밀도에 이를 것으로 예측된다.

• Korean Journal of Optics and Photonics
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• v.32 no.2
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• pp.68-78
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• 2021

A subminiature catadioptric omnidirectional optical system (SCOOS) with 2 mirrors, 6 plastic aspherical lenses, and an illumination system of 6 light emitting diodes, to observe the 360° panoramic image of the inner intestine, is optically designed and evaluated for a capsule endoscope. The total length, overall length, half field of view (HFOV), and F-number of the SCOOS are 14.3 mm, 8.93 mm, 51°~120°, and 3.5, respectively. The optical system has a complementary metal-oxide-semiconductor sensor with 0.1 megapixels, and an illumination system of 6 light-emitting diodes (LEDs) with 0.25 lm to illuminate on the 360° side view of the intestine along the optical axis. As a result, the spatial frequency at the modulation transfer function (MTF) of 0.3, the depth of focus, and the cumulative probability of tolerance at the Nyquist frequency of 44 lp/mm and MTF of 0.3 of the optimized optical system are obtained as 130 lp/mm, -0.097 mm to +0.076 mm, and 90.5%, respectively. Additionally, the simulated illuminance of the LED illumination system at the inner surface of the intestine within HFOV, at a distance of 15.0 mm from the optical axis, is from a minimum of 315 lx to a maximum of 725 lx, which is a sufficient illumination and visibility.

• Korean Journal of Optics and Photonics
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• v.32 no.2
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• pp.79-85
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• 2021

In this paper, a study is conducted on the design of an optical system of a time-of-flight (TOF) laser distance sensor that can measure long distances by minimizing beam divergence. When measuring a long distance, the amount of light on the object's surface decreases as the distance increases, due to the diffusion angle of the laser beam, and thus the beam at the sensor also decreases, causing measurement errors. In general, a cylindrical lens is used to reduce the divergence beam angle. However, an optical system using a cylindrical lens has the problem of degraded performance due to the difficulty with assembly tolerance, as well as the problem of the increased size of the optical system, and thus the use of aspherical lenses has been increasing recently. Therefore, in this study, the optical efficiencies and assembly tolerances of optical systems using respectively a cylindrical lens and an aspherical lens are compared and analyzed.

• Korean Journal of Optics and Photonics
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• v.22 no.4
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• pp.161-169
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• 2011

In this paper, a tolerance allocation method using Monte-Carlo simulation with measured reflective eccentricity for high-sensitive IR optics is proposed. During optics fabrication and alignment, reflective eccentricity was measured using an optical centration measurement instrument. A Monte-Carlo simulation was performed using measured eccentricity data, and it gives statistical estimated performance of the optics after fabrication. The validity of the proposed tolerance allocation method was verified comparing the estimated MTF result with the measured MTF result of the fabricated optics.