• Journal of the Korean Society for Precision Engineering
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• v.27 no.5
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• pp.22-26
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• 2010

Recently, due to the tremendous growth of media technology, demands of the aspheric glass lens which is a high-performance and miniaturized increase gradually. Generally, the aspheric glass lens is manufactured by Glass Molding Press (GMP) method using tungsten carbide (WC) mold core. In this study, the thermal deformation which was occurred by GMP process was analyzed and applied it to compensate the aspheric glass lens. The compensated lens was satisfied that can be applied to the actual specifications.

• Journal of Korean Ophthalmic Optics Society
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• v.10 no.2
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• pp.133-138
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• 2005

As Aspheric lenses have producted to development for disadvantage of spherical lenses, the purpose of use on aspheric lenses is in improvement of the imaging quality and decrement of the number of lenses used, they are used for lessen the mass and volume in optical science. The skills to produce optical data and the aspheric are seen as high technology today. The optical science which is composed of aspheric provides broadening view of things and high efficiency. In addition, it provides many advantages such as providing image and reducing the weight. Now, I study with techniques of processing and measuring aspheric to satisfy the necessity of increasing in aspheric data. Furthermore. I emphasize that the techniques of producing, measuring, and evaluating in the aspheric lenses have constantly developing today.

• Journal of the Korean Society for Precision Engineering
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• v.26 no.1
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• pp.51-56
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• 2009

Recently, with the increasing lightness and miniaturization of high resolution camera phones, the demand for aspheric glass lens has increased because plastic and spherical lens are unable to satisfy the required performance. An aspheric glass lens is fabricated by the high temperature and pressure molding using a tungsten carbide molding core, so precision grinding and coating technology for the molding core surface are required. This study investigates the effect of diamond-like carbon (DLC) and rhenium-iridium (Re-Ir) coating For aspheric molding core surface. The grinding conditions of the tungsten carbide molding core were obtained by design of experiments (DOE) for application in the ultra precision grinding process of the tungsten carbide molding core of the aspheric glass lens used in 5 megapixel, $4{\times}$ zoom camera phone modules. A tungsten carbide molding core was fabricated under this grinding condition and coated with the DLC and Re-Ir coating. By measurements, the effect of DLC and Re-Ir coating on the form accuracy and surface roughness of molding coer was evaluated.

• Korean Journal of Optics and Photonics
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• v.24 no.3
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• pp.111-119
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• 2013

A large aspheric mirror is a key component for large astronomical telescopes and high resolution satellite cameras. Since it is large and has an aspheric form, it is much more difficult to fabricate it compared to the similar size of spherical mirror. Especially, the opto-mechanical design and analysis is critical to reduce the deformation of mirror surface due to the external forces such as gravity or temperature change, as the mirror size is larger and lightweighting ratio is increased. The design requirements for the mirror are different depending on the particular ground and space applications because the environmental conditions are changed. In this paper, we explain the opto-mechanical design and analysis for ground and space applications that are among the most difficult to achieve among several technologies related to development of the large aspheric mirror.

• Journal of the Optical Society of Korea
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• v.5 no.3
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• pp.70-75
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• 2001

Next Generation Space Telescope (NGST) is under design study for proposed launch around 2008. It will take over the task of Hubble Space Telescope (HST) and provide much more detailed information about celestial objects. Present large telescopes both in space and on the ground contain aspheric mirrors, called Ritchey-Chretien type. As the size of the telescope becomes larger and the optical quality is requested to be higher, reaching the diffraction limit, more accurate optical testing methods are required. However, there are few testing methods which can achieve the required accuracy for aspheric optics, and none of them has achieved it with certainty. The failure of producing the primary mirror of the Hubble Space Telescope to meet specification is a good example. Moreover, testing aspheric mirrors of large convex form adds the difficulty to extreme. In this paper, space telescopes and large ground-based telescopes are surveyed and testing methods for aspheric optics are reviewed. a method of testing aspheric convex mirrors is suggested.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2008.10a
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• pp.363-366
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• 2008

The transcription characteristics in the molding of aspheric glass lenses for camera phone modules have been investigated experimentally. The surface topographies of both the form and the roughness were compared between the mold and the molded lens. The molded lens showed a transcription ratio of 93.4%, which is obtained by comparing the form accuracy (PV) values of the mold and the molded lens. The transcription of the roughness topography was ascertained by bearing ratio analysis.

• Journal of Korean Ophthalmic Optics Society
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• v.6 no.1
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• pp.93-100
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• 2001

We analyzed aspheric patterns after we investigated zoom lens' constructions and optical capacities of a ordinary designed 35mm camera with an aspheric zoom lens system in this research. As this lens system was the zoom lens system about infinite object point, it was made to get a short back focal length, be able to use a lens unit more close to the image plane, and be used the compact camera which got a viewing system. The zoom ratio of the system was 1 : 2 and it got a positive and negative power's distribution. As it was determined the 35~70 mm focal length range which the most common people used, it might be called economic optical system considered universality. As it was used two aspheric surface, it was used just three lens, compensated the aberration and schemed lens' miniaturization, lightweightization, and the decrease effect of the unit cost of production.

• Journal of Korean Ophthalmic Optics Society
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• v.7 no.1
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• pp.63-67
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• 2002

In this paper we analyzed the optical property after we chose the lens system to cover a wide angular field which is designed to use a established designed meniscus negative outer element. The special quality of the system is to offer a wide angular field by getting only one outer negative element and to be a compacted optical system to utilize the good point of miniaturization and light-weighturization by using two aspheric surfaces. Also, we observed the aberration correction of a aspheric as we investigated two aspheric's forms to use for a aberration correction.

• Korean Journal of Optics and Photonics
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• v.24 no.4
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• pp.189-195
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• 2013

An F/1.2 infrared optical system that involves two aspheric BD-2 lenses and an aspheric diffractive surface was designed over $8-14{\mu}m$ with a field angle of $15.2^{\circ}$. The system may be used in uncooled cameras and is analyzed using beam synthesis propagation (BSP). The diffractive surface is modeled as a physical surface with a given thickness, and results are compared with those obtained by conventional methods, such as the exit-pupil method and a method which superposes diffraction orders.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.06a
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• pp.469-470
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• 2006

The purpose of this research was to investigate and to find out the optimal annealing condition to mold an aspheric glass to be used for mobile phone module having 2 megapixel and $2.5{\times}$ zoom. Taking annealing rate and re-press temperature after molding as molding variables under the identical molding temperature and pressure, a glass lens was molded. And, Form Accuracy, Lens Thickness, Refractive Index, and Modulation Transfer Function(MTF) were measured in order to observe characteristics of molded lens, and then optimal annealing conditions were determined based on the resulting data. Properties of lens molded under the optimal conditions revealed Form Accuracy[PV] $0.2047\;{\mu}m$ in aspheric surface, and $0.2229\;{\mu}m$ in plane, and MTF value was 30.3 % under 80 lp/mm.