• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2006년도 춘계학술대회 논문집
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• pp.221-222
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• 2006

In recent years, the demands of the aspherical glass lenses increase since it is difficult to obtain the desirable performance in the plastic lens. Glass lens is manufactured by the forming with high precision mold core. This paper presents the analysis of optimal grinding condition of tungsten carbide(WC, Co0.5%) using design of experiments(DOE). The process parameters are turbin spindle, work spindle, feedrate and depth of cut. The experiments results are evaluated by MINITAB software.

• Current Optics and Photonics
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• 제2권4호
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• pp.324-331
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• 2018

This paper describes a symmetric method for determining a combination of element power and optical material to design a catadioptric system with corrected color aberration and flat Petzval curvature. To graphically obtain the solutions, a glass chart containing the Abbe number, the refractive index, and the optical power, which are closely related to these aberrations, is suggested. First, we recompose an optical system as a doublet of the specific lens and an equivalent single lens, and then locate both lenses on lines that are symmetric to each other on a glass chart, through changing the lens parameters effectively. Utilizing this method, an achromatic catadioptric system with flat Petzval curvature is obtained.

• 한국공작기계학회논문집
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• 제16권6호
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• pp.163-167
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• 2007

A field emission electron gun including 3 electrodes including one cathode and two anodes is very important for high resolution electron microscope. To have functions to control the initially-emitted electron beam, two anodes act as an electrostatic lens according to equipotential lines by adjusting the spot size, intensity, and working distance. To verify the action of the electron beam by the electrostatic lens by changing several parameters such as electrode shape, displacement and applied voltage to the electrodes, the two lenses were design and simulated and then their performances were analyzed with angular beam intensity(distribution), electrical optic axis variation and their stability.

• 한국금형공학회:학술대회논문집
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• 한국금형공학회 2008년도 하계 학술대회
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• pp.143-148
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• 2008

In order to produce high-quality optical components, aspheric lenses have been widely applied in recent years. An aspheric lens consists of aspheric surfaces instead of spherical ones, which causes difficulty in the design process as well as the manufacturing procedure. Although injection molding is widely used to fabricate optical lenses owing to its high productivity, there remains lots of difficulty to determine appropriate mold design factors and injection molding parameters. In the injection molding fields, computer simulation has been effectively applied to analyze processes based on the shell analysis so far. Considering the geometry of optical lenses, a full-3d simulation based on solid elements has been reported as a reliable approach. The present work covers three-dimensional injection molding simulation and relevant deformation analysis of an injection molded plastic lens based on 3d solid elements. Numerical analyses have been applied to the injection molding processes of three aspheric lenses for an image sensing module of a mobile phone. The reliability of the proposed approach has been verified in comparison with the experimental results.

• 한국광학회지
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• 제20권3호
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• pp.148-155
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• 2009

본 연구에서는 광학계의 굴절률, 중심두께 및 곡률반경에 대한 설계변수가 온도변화에 따라 1차 특성 및 결상성능에 어떠한 영향을 미치는지 분석하고, 이로부터 온도보정 설계를 실시하였다. 광학설계 변수들을 각각의 사용온도에 해당되는 값으로 변경한 후, 기존의 coupling 및 ruler 설계 개념을 폰 카메라용 렌즈설계에 적용하여 온도보정을 고려한 설계방법을 제시하였다. 본 연구에서 제시한 온도보정 설계개념을 4매 구성의 1/3.2" 5M 렌즈계에 최초로 적용하여 최적 설계한 결과, 폰 카메라용 렌즈에 대한 일반사양을 만족시키는 동시에 사용온도 $-10^{\circ}C{\sim}+60^{\circ}C$에서의 후초점거리 변화량에 대한 요구사양(${\Delta}BFL{\leq}10{\mu}m$)도 만족시켰다. 또한 최적 설계된 렌즈계의 전장(TTL)은 5.5 mm로 매우 컴팩트한 구성이다. 따라서 본 연구의 결과는 휴대폰 카메라 및 감시 카메라용 광학계 개발에 활용이 가능할 것으로 기대된다.

• Journal of the Optical Society of Korea
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• 제17권5호
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• pp.447-453
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• 2013

A micro zoom system without moving elements by use of two liquid lenses is designed and optimized in this paper. The zoom equations of the system composed of two liquid lenses are deduced. The structure parameters including radius and thickness of a conical double-liquid electrowetting based lens are analyzed and calculated. Because the liquid thickness varies non-linearly with the radius of the interface, it's very difficult to optimize a real liquid lens using commercial optical design software directly. Through the Application Programming Interface (API) of the optical design software CODE V, a zoom system with two real electrowetting based liquid lenses is modeled and optimized. A two-liquid-lens zoom system without moving elements, with a zoom factor of 1.8 and a compact structure of 10 mm is designed for illustration. This can be useful for the camera design of mobile phones, tablets and so on. And this paper presents a convenient way of designing and optimizing a zoom system including liquid lenses by commercial optical design software.

• Journal of the Optical Society of Korea
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• 제14권4호
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• pp.431-437
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• 2010

A stack of gradient-index (GRIN) rod lenses cannot be used for coherent anti-Stokes Raman scattering (CARS) microendoscopy for insertion to internal organs through a surgical keyhole with minimal invasiveness. That's because GRIN lens has large amount of inherent chromatic aberrations in spite of absolutely requiring a common focus for pump and Stokes beam with each frequency of ${\omega}_p$ and ${\omega}_S$. For this endoscopic purpose, we need to develop a long slender probe-type objective, namely probe-type microscope objective (PMO). In this paper, we introduce the structure, the working principle, and the design techniques of PMO which is composed of a probe-type lens module (PLM) and an adaptor lens module (ALM). PLM is first designed for a long slender type and ALM is successively designed by using several design parameters from PLM for eliminating optical discords between scanning unit and PLM. A combined module is optimized again to eliminate some coupling disparities between PLM and ALM for the best PMO. As a result, we can obtain a long slender PMO with perfectly diffraction-limited performance for pump beam of 817 nm and Stokes beam of 1064 nm.

• 한국전기전자재료학회논문지
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• 제20권8호
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• pp.720-725
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• 2007

This study investigated the pressing conditions in the molding of aspheric glass lenses for the mega pixel phone camera module using the DOE method. Tungsten carbide (WC; Japan, Everloy Co., 002K),which contained 0.5 w% cobalt (Co), was used to build the mold. The mold surface was ultra-precision ground and polished, and its form accuracy (PV) was 0.85um in aspheric surface. We selected four factors, pressing temperature, force and time of first step, and force of second step, respectively, as the parameters of the pressing process. in order to reduce the number of experiments, we applied fractional factorial design considering the main effects and two-way interactions. The analysis results indicate that the only two main effects, the pressing temperature and the time of pressing step 1, are available for the form accuracy (PV) of the molded lens. The analysis results indicated that the best combination of the factors for lowering the form accuracy(PV) value of molded lens was to have them at their low levels.

• 한국태양에너지학회 논문집
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• 제40권5호
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• pp.23-34
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• 2020

Concentrator photovoltaic (CPV) system consists of high-quality complex optical elements, mechanical devices, and electronics components and can have the advantages of high integration and high-efficiency energy sources. III-V compound semiconductor cells have proven performance based on high reliability in the aerospace field, but have characteristics that require absolute support of the balance of systems (BOS) such as solar position trackers, receivers with heat sinks, and housing instruments. To determine the optimum parameters of secondary optical elements (SOEs) design for CPV systems, we designed three types of CPV modules, classified as non-SOEs type, reflective mirror type, and CPC lens type. We measured the I-V and P-V characteristics of the prototype CPV modules with the angle of inclination varying from 0° to 12° and with a 500-magnification Fresnel lens. The experimental results assumed misalignment of the solar position tracker or module design of pinpoint accuracy. As a result, at the 0° tilt angle, the CPC lens produced lower power due to the quartz transmittance ratio compared to that by other SOEs. However, for tilt angles greater than 3°, the CPC lens type module achieved high efficiency and stability. This study is expected to help design high-performance CPV systems.

• 한국안광학회지
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• 제15권3호
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• pp.235-240
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• 2010

목적: 본 연구에서는 조절작용에 있어 유일한 굴절기관인 수정체에 대한 최근의 측정결과들을 고려하여 조절이 포함된 모형안을 제시하고자 한다. 방법: 제안된 수정체는 2개의 비구면으로 구성되었으며, 2개의 면이 만나는 점들은 수직으로 이은 선을 직경이라 하고 광축과 만나는 점을 원점으로 전면부와 후면부로 나누었다. 조절이 진행되는 동안, 굴절률은 균질하고 변화가 없도록 간략화하였으며, 수정체 전면부의 부피와 후면부의 부피는 각각 변화가 없다고 가정하였다. 결과: 본 연구에서는 조절자극량이 커질수록 수정체의 직경이 감소하면서 전면과 후면의 곡률반경이 감소하고 두께는 증가한다. 각 조절단계에서의 곡률반경과 두께를 구할 수 있으며, 계산된 값들로 굴절력 변화를 구하여 조절반응량으로 나타낼 수 있다. 조절자극량에 따른 매개변수 변화량들은 실안의 측정결과와 유사한 움직임을 보였다. 결론: 이와 같은 결과들은 각 조절단계에서 수정체의 부피와 굴절률이 변하지 않는 가정 아래 동적 매개변수의 변화량을 구할 수 있음을 보여준다.