• Title/Summary/Keyword: Spherical Glass lens

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Defect Evaluation of Optical Lens by Resonant Ultrasound Spectroscopy (공명초음파분광법을 활용한 광학기기용 렌즈의 결함평가)

  • 김성훈;백경윤;김영남;양인영
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2004.10a
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    • pp.1491-1495
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    • 2004
  • In this paper, resonant ultrasound spectroscopy(RUS) was used to determine the natural frequency of a spherical and a aspherical lens. The objective of the paper is to evaluate defect and shape error by using nondestructive evaluation method with Resonant Ultrasound Spectroscopy(RUS). The principle of RUS is that the mechanical resonant frequency of the materials depends on density, and the coefficient of elasticity. We evaluated existence of flaws through comparison with resonant frequency of a spherical and a aspherical lens. The spherical glass lenses were made of BK-7 glass, one's diameter in 2mm and 5mm. The polished spherical glass lenses had no deflection or a deflection below 2.0${\mu}{\textrm}{m}$. Also, The aspherical lens were made of same material and ones diameter in 7mm and thickness in 3.4mm. In the experiment, we were performed to investigate relationship between frequency measuring parameter($\beta$) and mass of each specimens. The difference between resonant frequency and mode of aspherical glass lens which has no defect was distinguished from aspherical glass lens which has some defects.

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The Evaluation on the frequency Characteristics of the Optical Glass Lens by Resonant Ultrasound Spectroscopy (RUS법에 의한 광학기기용 렌즈의 주파수 특성평가)

  • Yang, In-Young;Kim, Seung-Hoon
    • Journal of the Korean Society for Nondestructive Testing
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    • v.25 no.2
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    • pp.127-132
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    • 2005
  • The optical glass lens is required high dimensional precision such as the lack of defect. In this paper, we examined the detectable defect by using the resonant ultrasound spectroscopy(RUS). The RUS is the measurement system which is to excite the specimen and to inspect the differences of resonant frequency pattern between acceptable specimen and specimen which has some defects. In this paper, for nondestructive evaluation by using RUS, we measured the resonant frequency of each specimen which is spherical and aspherical glass lens. With the results, we knew the polishing processing degree of spherical glass lens by the measured resonant frequency and could evaluate the characteristic of aspherical glass lens about some flaws.

A Study on Grinding Characteristics of Aspherical Glass Lens core of High-pixel Digital Camera in Diamond Grinding Process (고화소 디지털 카메라 비구면 Glass렌즈 초정밀연삭 특성에 관한 연구)

  • 현동훈;이승준
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.12 no.2
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    • pp.31-36
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    • 2003
  • Electronic or measuring instruments equipped with aspherical lens have recently been used since aspherical lens is more effective than spherical one. for the mass production of aspherical lenses, specific molds with precisely machined cores should be prepared. Some researches on the aspherical lens machining have been carried out to date. However, ultra-precise finding of aspherical or mold core has not been fully studied. In this study, the ultra-precise grinding and evaluating system were established to investigate the finding characteristics of aspherical lenses. Unlike conventional grinding process, since a highly-precise lathe were operated in a clean room without vibration the experimental results can be very useful for further studies on ultra-precise grinding process.

A Study on the Development and Performance Evaluations for a Self-diagnostication Ultra-precision Lens Polishing Machine (자기 진단형 초정밀 렌즈 폴리싱기의 개발 및 성능 평가에 관한 연구)

  • Park S.H.;Lim S.H.;Lee C.M.
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2006.05a
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    • pp.241-242
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    • 2006
  • Spherical glass lenses are used in many optical industries. The curvature, eccentricity and height of a tool affect the surface roughness and curvature of lenses. The purpose of this study is the development and performance of a self-diagnostication ultra-precision lens polishing machine. In this paper, structure analysis is performed to reduce maximum displacement and to maintain outside the resonance region by CATIA V5. A spherical center setting gage is developed to increase accuracy of the manufactured lenses. The surface roughness, curvature and thickness of the manufactured lenses are measured and studied.

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Optimization of optical design for Eye Glass Display using hybrid aspheric lens (Hybrid 비구면 렌즈를 이용한 Eye glass Display용 광학시스템의 최적화)

  • Kim, T.H.;Park, K.B.;Park, Y.S.;Kim, H.W.;Seok, J.M.;Moon, H.C.
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2005.05a
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    • pp.123-126
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    • 2005
  • Eye Glass Display (EGD) with microdisplay to realize the virtual display can make the large screen, so virtual image has been developed by using microdisplay panel. This paper shows study of low cost lens design and simulation for microdisplay system with 0.6"LCoS panel. Lens design optimized consider to spherical aberration, astigmatism, distortion, and chromatic aberration. Code V is used and it designed an aspheric lens about exit pupil 6mm, eye relief 20mm and 35 degree of field of view (FOV). With the application this aspheric lens to liquid crystal on silicon (LCOS) type's microdisplay, virtual image showed 50 inch at 2m. One side of the aspheric lens was constituted from diffractive optical element (DOE) for the improvement in a performance. It had less than 2.5% of distortion value and modulation transfer function in axial had 20% of resolution with 32 lp/mm spatial frequency. The optical system is suitable for display of 15.6 mm-diagonal with SVGA.

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Study on Ultra-Precision Grinding Processing for Aspheric Glass Array Lens WC Core (비구면 유리 어레이 렌즈 성형용 초경합금 코어 초정밀 연삭 가공에 관한 연구)

  • Ko, Myeong Jin;Park, Soon Sub
    • Journal of the Korean Society for Precision Engineering
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    • v.33 no.11
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    • pp.893-898
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    • 2016
  • Plastic array lens are cheap to manufacture; however, plastic is not resistant to high temperatures and moisture. Optical glass represents a better solution but is a more-expensive alternative. Glass array lens can be produced using lithography or precision-molding techniques. The lithography process is commonly used, for instance, in the semiconductor industry; however, the manufacturing costs are high, the processing time is quite long, and spherical aberration is a problem. To obtain high-order aspherical shapes, mold-core manufacturing is conducted through ultra-precision grinding machining. In this paper, a $4{\times}1$ mold core was manufactured using an ultra-precision machine with a jig for the injection molding of an aspherical array lens. The machined mold core was measured using the Form TalySurf PGI 2+ contact-stylus profilometer. The measurement data of the mold core are suitable for the design criterion of below 0.5 um.

Optimization of optical design for Eye Glass Display

  • Moon, H.C.;Kim, T.H.;Park, K.B.;Park, Y.S.;Seok, J.M.;Kim, H.W.
    • 한국정보디스플레이학회:학술대회논문집
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    • 2005.07b
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    • pp.1603-1606
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    • 2005
  • Eye Glass Display (EGD) with microdisplay to realize the virtual display can make the large screen, so virtual image has been developed by using microdisplay panel. This paper shows study of low cost lens design and simulation for microdisplay system with 0.6" Liquid Crystal on Silicon (LCoS) panel. Lens design optimized consider to spherical aberration, astigmatism, distortion, and chromatic aberration. Code V is used and it designed an aspheric lens about exit pupil 6mm, eye relief 20mm and 35 degree of field of view (FOV). With the application this aspheric lens to LCOS type's microdisplay, virtual image showed 50 inch at 2m. One side of the aspheric lens was constituted from diffractive optical element (DOE) for the improvement in a performance. It had less than ${\pm}2%$ of distortion value and modulation transfer function in axial had 20% of resolution with 30 lp/mm spatial frequency. The optical system is suitable for display of 0.6"-diagonal with SVGA.

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Telephotolens design with refractove/diffractive hybrid lens

  • Hong, Young-Ghi;Kim, Sun-Il;Yeo, Wan-Gu;Lee, Chul-Koo
    • Journal of the Optical Society of Korea
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    • v.1 no.2
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    • pp.74-80
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    • 1997
  • 300mm F/4.0 telephotolens with diffractive hybrid lens was designed, and its optical performance was tested and compared with a traditional lens system. DOE(Diffractive Optical Element) reconstructs wavefronts using wave phenomena of light to focus the incident light onto the focal point and has negative Abbe number while a traditional lens uses geometrical phenomena of light and has positive Abbe number. Therefore, a diffractive hybrid lens containing both refractive and diffractive elements can remarkably correct chromatic aberration and spherical aberration of an optical system. We investigated and analyzed the optical properties of a diffractive hybrid lens for the visible spectrum, and we used a difractive hybrid lens to design and evaluate a 300mm F/4.0 telephotolens without the special LD(Low Dispersive) glass lens which is costly and difficult to manufacture. Most traditional telephotolenses use the special LD glass for chromatic aberration correcton. Optical performance tests such as resolution and characteristics of aberration of both lens systems using a diffractive hybrid lens and traditional lens were performed.

A Study on Influence of PV and Ra with Re-Ir Coating of WC Core Surface for Glass Molding Lens (성형용 초경합금(WC) 코어면의 Re-Ir 코팅이 형상정도와 표면조도에 미치는 영향에 관한 연구)

  • Kim, Hyun-Uk;Kim, Sang-Suk;Kim, Hye-Jeong;Kim, Jeong-Ho
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.20 no.9
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    • pp.808-811
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    • 2007
  • Aspheric glass lens have recently been used in camera phone module because they are more effective than spherical ones. In this paper, the grinding condition of the tungsten carbide molding core has been found after applying DOE to the development of the aspheric glass lens for the 3 Megapixel and 2.5x camera-phone module. Also, the ultra precision grinding process was investigated under this condition by experiment. Re-Ir coating was applied on the ground surface of the tungsten carbide molding core. The influence of Re-Ir coating on the form accuracy and surface roughness of molding core was compared and evaluated. The form accuracy and surface roughness of the molding core were improved by application of Re-Ir coating on the surface of the tungsten carbide molding core.

Aspherical prism lens design and manufacture of a small size and light wight EGD (비구면 프리즘 렌즈를 이용한 소형 경량의 EGD용 광학계 설계 및 제작)

  • Kim, Tae-Ha;Park, Kwang-Bum;Kim, Mi-Jung;Park, Young-Su;Kim, Hwi-Woon;Moon, Hyun-Chan
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2007.11a
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    • pp.454-454
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    • 2007
  • Eye Glass Display (EGD) with microdisplay to realize the virtual display can make the large screen, so virtual image has been developed by using microdisplay panel. This paper shows study of spherical prism lens design and manufacture of a small size and light weigh EGD with 0.59" OLED panel. Code V is used and it designed an aspherical prism lens about eye relief 25mm and 42 degree of filed of view (FOV). With the application this aspheric prism lens to OLED type's microdisplay, virtual image showed 60 inch at 2m. It had less than 2% of distortion value and modulation transfer function in axial had 30% of resolution with 32 lp/mm spatial frequency. We made an injection molding bases to lens designed.

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