• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.20 no.4
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• pp.472-477
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• 2011

This paper shows the method of fabrication of a micro lens array comprised of a Nipkow disk used in a large-area, high-speed confocal microscopy. A Nipkow disk has two components, a micro lens array disk and a pinhole array disk. The microlens array focuses illumination light onto the pinhole array disk and redirects reflected light from a surface to a sensor. The micro lens which are positioned in order on a disk have a hemispheric shape with a few tens of micron in diameter, and can be fabricated by a variety of methods like mechanical machining, semiconductor process, replication process like imprinting process. This paper shows how to fabricate the micro lens array which has a long focal length by reflow and imprinting process.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2006.05a
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• pp.105-108
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• 2006

It has been issued to fabricate nano-scale patterns with large-scale in the field of digital display. Also, large-scale fabrication technology of nano pattern is very important not only for the field of digital display but also for the most of applications of the nano-scale patterns in the view of the productivity. Among the fabrication technologies, UV nano imprinting process is suitable for replicating polymeric nano-scale patterns. However, in case of conventional UV nano imprinting process using flat mold, it is not easy to replicate large areal nano patterns. Because there are several problems such as releasing, uniformity of the replica, mold fabrication and so on. In this study, to overcome the limitation of the conventional UV nano imprinting process, we proposed a continuous UV nano imprinting process using a pattern roll stamper. A pattern roll stamper that has nano-scale patterns was fabricated by attaching thin metal stamper to a roll base. A continuous UV nano imprinting system was designed and constructed. As practical examples of the process, various nano patterns with pattern size of 500, 150 and 50nm were fabricated. Finally, geometrical properties of imprinted nano patterns were measured and analyzed.

• Journal of the Korean Electrochemical Society
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• v.15 no.4
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• pp.249-255
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• 2012

The planar-type amperometric creatinine biosensor employing an additional enzyme layer containing creatine kinase and adenosine triphosphate was developed to eliminate severe interference from creatine. In the additional enzyme layer, an interfering substance, creatine is converted to noninterfering product, phosphocreatine. Furthermore, the carbon electrode electroplated with Pt black(Pt-B) was employed to fabricate creatinine biosensors with improved sensor performance(e.g., sensitivity, reliability, and reproducibility). The creatinine levels in an unknown sample were determined within less than 5% errors using creatinine microsensors equipped in a flow-cell cartridge.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.10a
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• pp.91-94
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• 2005

With increasing demands for large-scale micro-optical components in the field of digital display, the establishment of large-scale fabrication technology fur polymeric patterns has become a priority. The starting point of any polymer replication process is the mold, and the mold often has flat surface. However, It is very hard to replicate large-scale micro patterns using the flat mold, because the cost of large-scale flat mold was very high, and some uniformity and releasing problems were often occurred in large scale flat molding process. In this study, a UV roll imprinting system to overcome the financial and fabrication issues of large-scale pattern replication process was designed and constructed. As a practical example of the system, a lenticular lens with radius of curvature of $223{\mu}m$ and pitch of $280{\mu}m$, which was used to provide wide viewing angle in projection TV, was designed and fabricated. The roll stamper was fabricated using direct machining process of aluminum roll base. Finally, the shape accuracy and uniformity of roll imprinted lenticular lens sheet were measured and analyzed.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2018.06a
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• pp.89-89
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• 2018

스마트 폰이나 내비게이션, 태블릿 PC, TV 등 디스플레이 소자가 휴대 가능해지고 고급화되면서 빛 반사로 인한 눈부심, 시인성 저하 등에 대한 문제가 제기되고 있다. 디스플레이의 반사방지를 위해 방현성(anti-glare) 및 반사방지(anti-reflection) 특성의 코팅이나 기능성 필름에 대한 연구 개발이 이루어지고 있다. 특히 반사방지 기능 부여를 위해 나방눈(moth-eye) 구조를 모방하여 표면 나노 구조 형상화에 대한 연구가 활발히 진행되고 있지만, 나노 임프린팅 및 리소그라피 공정을 통한 패턴 공정은 마스크나 몰드를 필요하고 대면적 제작에 어려움이 있다. 본 연구에서는 폭 300 mm급 롤투롤 이온빔 표면처리를 통해 나노 구조 몰드 필름을 제작하였고, 이형용 수지를 이용한 표면 구조 전사를 통해 모스 아이 구조와 같은 나노 구조 패턴이 전사되는 것을 확인하였다. 나노 구조가 전사된 필름에 대한 투과도 관찰 결과, 전체 투과도 91% 이상으로 투과도가 약 3% 향상되고 반사도는 저하되는 결과를 확인하였다. 롤투롤 장비를 이용하여 대면적 필름 제작이 가능한 것을 확인하였고, 나노패턴의 구조 형성 및 반사방지 기능에 대한 신뢰성 검토를 통해서 양산화 가능할 것이라 전망된다.

• Transactions of the Korean hydrogen and new energy society
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• v.12 no.2
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• pp.137-146
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• 2001

고상 반응법을 이용하여 $La_{0.7}Sr_{0.3}Ga_{0.6}Fe_{0.4}O_{3-{\delta}}$ 분말을 합성하고 혼합전도체 분리막을 소결하여 제조하였다. 제조된 분리막은 $LaGaO_3$에 일치하는 폐롭스카이트 결정구조를 나타내었으며 95% 이상의 높은 상대밀도를 나타내었다. 스크린 프린팅 방법으로 $La_{0.6}Sr_{0.4}CoO_{3-{\delta}}$ 후막을 disk의 양 표면에 코팅하였으며 코팅 막은 비교적 치밀한 미세구조를 나타내었다. 코팅되지 않은 분리막과 코팅된 분리막의 산소투과 성능을 비교 실험한 결과 $850^{\circ}C$에서 동일한 두께의 코팅된 분리막의 정상상태 산소 투과 유속이 $0.7{m{\ell}}/min.cm^2$ 정도로 코팅되지 않은 분리막에 비해 약 2~3배로 높게 나타났다.

• Transactions of the Society of Information Storage Systems
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• v.6 no.1
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• pp.37-40
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• 2010

Fresnel lens is a kind of refractive optical lens with various advantages. It has nearly flat shaped optical lens that has small mass. Fresnel lens has number of applications in the compact optical systems. Recently, demands of high quality Fresnel lens for small size optical systems such as illumination units, compact imaging systems, display units, information storage systems, optical detecting units had increased rapidly. Conventional manufacturing process of high quality Fresnel lens is direct machining. However, it is not suitable for mass production because of high cost and long cycle time. Replication method can provide cost effective mass production process. However, there are various issues about replication of Fresnel lens. Fresnel lens has number of sharp blade shape prism. In the replication process, this blade shape causes defects that can affect optical efficiency. In this study, replication processes; injection molding process and UV imprinting process, were developed and evaluated using Fresnel lens that has maximum pattern height of $250\;{\mu}m$ and aspect ratio of 1.5.

• Journal of the Semiconductor & Display Technology
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• v.10 no.4
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• pp.53-59
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• 2011

Recently there have been considerable attentions on nanoimprint lithography (NIL) by the display device and semiconductor industry due to its potential abilities that enable cost-effective and high-throughput nanofabrication. Although one of the current major research trends of NIL is large-area patterning, the technical difficulties to keep the uniformity of the residual layer become severer as the imprinting area increases more and more. In this paper we focused on the deformation of the $2^{nd}$ generation TFT-LCD sized ($370{\times}470mm^2$) large-area soft mold in the UV imprinting process. A mold was fabricated with PDMS(Poly-dimethyl Siloxane) layered glass back plate(t0.5). Besides, the mold includes large surrounding wall type protrusions of 1.9 mm width and the via-hole(7 ${\mu}m$ diameter) patterend area. The large surrounding wall type protrusions cause the proximity effect which severely degrades the uniformity of residual layer in the via-hole patterend area. Therefore the deformation of the mold was calculated by finite element analysis to assess the effect of large surrounding wall type protrusions and the flexiblity of the mold. The deformation of soft mold was verified by the measurements qualitatively.

• Journal of the Korean institute of surface engineering
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• v.50 no.6
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• pp.480-485
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• 2017

Soft mold imprinting method that uses nanostructured polymer mold was investigated for anti-reflection film fabrication. The nanostructured soft mold was polyethylene terephthalate(PET) irradiated by oxygen ion beams. The collisional energy transfer between oxygen ion and the polymer surface induced cross-linking and scission reactions, resulting in self-organized nanostructures with regular patterns of the wavenumber of $5{\mu}m^{-1}$. Post processes including ultra-violet curable resin coating and delamination fabricated anti-reflection films. The imprinted resin surface also showed the consistent wavenumber, $5{\mu}m^{-1}$. Pristine PET, oxygen ion beam treated PET, and imprinted replica sample showed total transmittance of 91.04, 93.25, and 93.57-93.88%, respectively.

• Journal of the Korean institute of surface engineering
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• v.49 no.2
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• pp.178-185
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• 2016

In this study, we have fabricated light guide plates (LGPs) in thin film form for edge type back light unit (BLU) by using UV imprint lithography. In the LGPs, the pattern of functional resins on PC and PMMA substrates were successfully transferred from original master mold through PVC stamp. Optimized pattern arrays with slowly-sloped density were designed to obtain high brightness and uniformity. We could obtain a relatively improved brightness of $950cd/m^2$ and a uniformity of 87.3% by using the NP-S20 functional resins at an input power of 1.3 W because NP-S20 resin could show high formability after UV hardening process. The LGP prepared on polymethylmethacrylate (PMMA) substrate exhibited higher brightness than that on polycarbonate (PC) substrate because PMMA has lower refractive index resulting in more refraction toward the vertical direction.