• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.1497_1498
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• 2009

This paper presents the simulation of micro-lens arrays based on dry and wet etching technique. Code V (Optical Research Associates Ltd) simulation was performed to extract optimal design parameters of a Micro-Lens Array(MLA). Thickness of UV adhesive, wavelength of laser source, curvature, and shape of lens surface were chosen for the design parameters. The simulation results showed that focal length of a MLA decreased with the increase of UV adhesive thickness. And the focal length depended on shape of lens surface and length of laser source.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2004년도 추계학술대회논문집
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• pp.280-283
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• 2004

Micro-lens patterned micro-mold fabrication method for Light Guiding Plate(LGP), kernel part of LCD-BLU(Back Light Unit), was presented. Instead of erosion dot pattern for LGP optical design, micro-lens pattern, fabricated by LIGA-reflow process, was applied. Optical pattern design method was also developed not only for negative pattern LGP, but also positive pattern LGP. During injection molding process, experimental study was conducted to improve replication quality and brightness of ${\sim}50um$ micro-lens pattern mold. The effect of mold temperature for the replication quality of micro-lens array was studied.

• International Journal of Precision Engineering and Manufacturing
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• 제9권4호
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• pp.32-38
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• 2008

This paper describes a fast tool control (FTC)-based diamond turning process for fabricating large-area high-quality micro-lens arrays. The developed FTC unit has a stroke of $48{\mu}m$ and a resonance frequency of 4.9 kHz. Micro-lens arrays were fabricated using a micro-cutting tool with a nose radius of $50{\mu}m$. The FTC unit was integrated with a force sensor so that the initial position of the micro-cutting tool with respect to the workpiece surface could be detected through monitoring the contacting force. The length and depth of the designed parabolic micro-lens profile were $190{\mu}m$ and $20{\mu}m$, respectively. A micro-lens array was fabricated on a cylinder surface over an area of ${\phi}55 mm{\times}40 mm$.

• 천문학회보
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• 제41권1호
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• pp.57.3-58
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• 2016

We analyze an optical system of a telescope based on Fresnel type objective lens as suggested by Hyde (1999). The Fresnel objective lens can be thin, light-weight and foldable, and therefore it is possible to develop a space telescope with an aperture larger than that of traditional telescopes. Moreover a lens, whatever it is either Fresnel type or conventional, allows much larger fabrication tolerances. We design a medium-sized telescope adopting Fresnel lens as an objective lens for use in space and possibly on the ground. The well-known chromatic aberration of the Fresnel primary lens is corrected by a field lens and another Fresnel lens using Schupmann method. An additional lens is used for forming images. We analyze the chromatic and off-axis aberrations of the proposed system analytically and suggest methods for the minimization of off-axis aberrations and for the operation in wider spectral range. We also conduct ray tracing and optimize the whole optical system with commercial software. Finally we present the design parameters of a telescope with an aperture of 0.5 to 1 meters, enabling diffraction limited operation for a moderate field of view about 10 arc-minutes.

• Journal of the Optical Society of Korea
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• 제19권6호
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• pp.629-637
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• 2015

Compact system cameras (CSCs) are commonly used nowadays and feature enhanced video functions and thin yet light interchangeable lenses. They differ from digital single-lens reflex (DSLR) cameras in their lack of mirror boxes. CSCs, however, have autofocus (AF) speeds lower than those of conventional DSLRs, requiring weight reduction of their AF groups. To ensure the marketability of large telephoto zoom lenses with fixed f/2.8 regardless of field angle variation, in particular, light weight AF groups are essential. In this paper, we introduce a paraxial optical design method and present a new, large, telephoto zoom lens with f/2.8 regardless of the field angle variation, plus a lightweight AF group consisting of only one lens. Using the basic paraxial optical design and optimization methods, we fabricated a new and lighter zoom lens system, including a single-lens, lightweight AF group with almost the same performance.

• 한국광학회지
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• 제16권6호
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• pp.508-515
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• 2005

MEMS 공정을 이용한 굴절렌즈 제작을 위하여, 슬릿 패턴을 갖는 마스크를 이동시키며 노광을 하는 가변 속도 이동식 마스크에 의한 노광 방법을 제안하였다. 감광제 면이 굴절렌즈의 곡면을 이루려면 감광제의 위치에 따른 노광 에너지의 분포를 조절해야 한다. 마스크의 패턴 형태와 이동 속돈 방향에 따라 감광제의 위치에 따른 노광 에너지의 분포를 이론적으로 분석하였으며, 감광제 박막에 임의의 곡면을 갖는 굴절렌즈 형상을 형성할 수 있음을 실험적으로 확인하였다. $100 {\mu}m$ 이상의 후막 감광제를 이용하거나, 혹은 곡면 형상을 갖는 얇은 감광제 형상을 마스크로 하여 이온식각을 수행하여 수백 ${\mu}m$ 정도의 최대높이를 갖는 렌즈 곡면형상을 제작 할 수 있었다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 추계학술대회논문집
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• pp.829-833
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• 2007

IPMC-EMIM (Ionic Polyer Metal Composites + 1-ethyl-3- methyl imidazolium trifluromethane sulfonate, EMIM-Tfo) is fabricated by substituting ionic liquid for water in Nafion film, which improves water sensitiveness of IPMC and guarantees uniform performance regardless of the surrounding environment. In this paper, we will introduce the design and analysis of AF Lens Actuator using IPMC-EMIM. We will briefly introduce the procedure of fabrication of IPMC-EMIM first, and proceed on to define the necessary variables, analyze performance by changing the value of the variables, make a designed AF Lens Actuator, and measure the performance of one of them.

• 한국정밀공학회지
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• 제29권3호
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• pp.261-265
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• 2012

In this study, glassy carbon was ground for lens core of glass mold press. Ultraprecision grinding process was applied for machining of core surfaces. During the process, brittle crack occurred because of hard-brittleness of glassy carbon. Author investigated optimized grinding conditions from the viewpoint of ductile mode grinding. Geometrical undeformed chip thickness was adopted for critical chip thickness that enables crack free surface. Machined cores are utilized for biaspheric glass lens fabrication and surfaces of lens were compared for verification of ground surface.

• 한국광학회지
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• 제16권5호
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• pp.428-432
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• 2005

마이크로칼럼에 사용되는 전자렌즈는 MEMS 공정으로 정밀하게 가공되어 기존의 전자칼럼에 비하여 광학수차를 최소화 할 수 있으며, 이는 전자칼럼의 성능 향상에 주요한 요소로 작용한다. 따라서 반도체 공정 방식(습식식각과 건식식각)에 의해 형성되는 렌즈구조에 따른 전자 광학계 연구는 중요한 의미가 있다. 마이크로칼럼을 구성하고 있는 전자방출원, 소스렌즈, 디플렉터, 포커스렌즈(Einzel lens) 중에서 전자빔의 특성에 가장 큰 영향을 주는 것은 소스렌즈이다. 본 연구에서는 소스렌즈의 extractor와 limiting aperture의 구조에 따른 전자빔 특성을 조사하였다.

• 센서학회지
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• 제18권1호
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• pp.33-41
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• 2009

A multilevel acoustic Fresnel lens (MAFL) for the ultrasonic imaging transducer of which center frequency is approximately 5.MHz was newly designed and fabricated. The phase level of the lens was 64, and the focal length and the aperture width were 30.mm and 11.mm, respectively. The characteristics of impulse response, acoustic field and imaging performance of the transducer attached the lens were compared with the transducer attached a conventional refraction type acoustic lens (RAL). The results show that the center frequency, the loop sensitivity, and the focal depth of the MAFL transducer were higher or larger than those of the RAL transducer by approximately 0.2.MHz, 1.4.dB, and 2.mm, respectively. Consequently, it was shown that the brighter acoustic images with higher lateral resolution and the increased imaging performance for deep targets can be obtained by using the MAFL transducer.