• 한국안광학회지
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• 제13권2호
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• pp.9-16
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• 2008

목적: 본 연구는 구면과 비구면 디자인 RGP렌즈를 착용하여 선호도와 경험적 피팅의 효용성을 비교하기 위해 시행하였다. 방법: 건강한 대학생 37명을 대상으로 우안에는 직경 9.3 mm의 구면 디자인, 좌안에는 직경 9.6 mm의 비구면 디자인렌즈로 피팅하였다. 경험적 피팅(on-K 피팅, 평균 K값-0.5D(또는 -1.0D) 피팅, 제조회사 가이드라인)의 베이스커브를 진단 피팅의 베이스커브와 비교하였다. 두 디자인 렌즈의 선호도와 피팅 형태(안검부착 피팅과 안검 사이 피팅)를 피팅 후 2주일에 조사하였다. 결과: 33명의 성공적인 RGP렌즈 착용자 중 구면 디자인 선호자는 76% 인 반면, 비구면 디자인 선호자는 24%로 나타났다. 안검 부착 피팅이 구면 디자인에서 67%이었고 비구면 디자인 에서는 64% 이었다. 진단 피팅과 비교하여 ${\pm}$0.50D이내 베이스커브의 수용할 수 있는 피팅 성공률은 구면 디자인 의 경우 on-K 피팅은 97%이고, 평균 K값-0.5D 피팅은 100%, 제조회사 가이드라인 피팅도 100%를 보였으나 비구면 디자인은 ${\pm}$0.50D 이내 베이스커브에 피팅이 되는 경우가 On-K 피팅은 91%, 평균 K값-1.0D 피팅은 79%, 제조 회사 가이드라인 피팅도 94%로 나타났다. 결론: 비구면 디자인의 시장 규모가 클지라도 여전히 검사 대상자들은 구면을 더 선호하였다. 경험적 피팅 중에서도 평균 K값-0.5D 피팅과 제조회사 가이드라인 피팅은 구면디자인에서 가장 적합한 피팅 방법일 수 있지만 비구면 디자인은 경험적 피팅 방법이 수용되기 어려운 것으로 나타났다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 하계학술대회 논문집
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• pp.289-289
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• 2009

Light emitting diode(LED) has many advantages including lower energy consumption and longer lifetime and eco-friendly in comparison with traditional light sources. Spheric plastic lens generally used in LED lighting occurs aberration and ghost image which give displeasure and deteriorate vision quality in human eyes. Using the optical program (LightTools$^{TM}$, CodeV$^{TM}$), we were confirm the aberration and ghost image in optical simulation and employed aspheric lens form in the lens design to improve these problems. From the comparison of the simulation results between the aspheric lens and the spheric lens, we were ascertain to be improved both aberration and Ghost image.

• 한국기계가공학회지
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• 제6권3호
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• pp.3-8
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• 2007

This study is for aspheric lens that is one of a core technology in the optical industry. The feature of a aspheric lens is not to have the spheric aberration. So in optical industry, aspheric lens are essential element to miniaturization, high effectiveness and light weight. In this study we applied a lay back-tracer method using the index of refraction to design aspheric lens. We developed the automatic design program for aspheric lens by user interfacing program VisualLISP in AutoCAD. And we manufactured aspheric lens and measured it.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2002년도 금형가공 심포지엄
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• pp.76-83
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• 2002

The injection molding of the plastic optics is basically same as the conventional molding except it requires very intricate control of all the molding processing parameters. In the plastic optics, the problem of injection molding is the shrinkage. The shrinkage must be removed and predicted. This shrinkage is becoming more important than any other problems in precision molding because it can affect the focal length of a lens or the total performance of the optical system. This study focused on avoiding the shrinkage that the mold design allows for the optics. In making mold, the surface accuracy(P-V) of the lower and lower mold are $0.201{\mu}m\;and\;0.434{\mu}m$ respectively. A surface roughness(Ra) is below $0.02{\mu}m$ due to selecting the appropriate tools and using the injection molding machine in high degree. In injection molding of the plastic lens, mold temperature, resine temperature and injecting pressure are important process parameters. Injection molding process is carried out according to varying mold temperature and injecting pressure. As a result P-V(peak to valley) of spheric lens is $3.478{\mu}m$ and that of aspheric lens is $1.786{\mu}m$.

• 건축역사연구
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• 제18권6호
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• pp.103-126
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• 2009

This study aims to discover historical trends and change of form of all stupas in India with observation of field study that is as direct as possible, by classifying, analyzing, and synthesizing the stupas. Study of Indian stupa in Korea has a number of shortcomings since only introductory partial approach has been made in order to seek the origin of Korean pagoda. This study also aims to correct errors of stupa terminology in Chinese character committed by misinterpretation of Hindi language which was established by precedent Japanese scholars several decades ago. Piled-up stupas were totally destroyed by pagans, therefore their remains tell us only of structure, material, sizeand disposition. However remains of carved stone at torana and drum give us clues as to the original form of stupa and worshipping activity, as well as change to a more luxurious form. Many rock cave stupas of India show us both simple forms matching the ascetic age of early Buddhism and luxurious changes in Mahayanan era introducing us to statues of Buddha. Indians recovered the spheric form of 'anda,' a Hindi term meaning cosmic egg, from the hemispheric form of the piled-up stupa. Therefore we might discard the erratic term of 'bokbal', which means an upset vessel. Railings and parasols became main factors of stupa design. Carved railings around stupa became a sign of divinity. Serious worshipping activity made drums long or high and created multi-embossed stripes. Bases of circular drums of some cave stupas changed their shapes to rectangular or octagonal. Single parasols became multiparasols of affluent flowerlike curved stems on carved stupa. Multistoried, elongated and high parasols of Gandhara stupas are closely related to such factors as diverse changes of form in Indian subcontinent. Four-sided torana gate and ayaka column of the circular form of original stupas suggest the rectangular form of subsequent East Asian pagoda, and higher and wider base of Indian stupas became the origin of East Asian rectangular pagoda.