• 한국광학회:학술대회논문집
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• 한국광학회 2008년도 하계학술발표회 논문집
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• pp.265-266
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• 2008

The environmental and mechanical reliability of planar lightwave circuit (PLC)-type optical splitter modules is investigated with references [1, 3]. The module is composed of Y-branching silica-based waveguides on Si connected to optical fiber with UV-curable adhesives and is packaged in a metal case which is filled with humidity-resistant resin. High optical performance such as low loss, low reflection, and thermal stability are obtained through the use of this fiber connection technique. Ten reliability tests including long-term environmental and mechanical and ALT test were carried out for more then ten $1{\times}32$ channel PLC splitter modules.

• 한국인쇄학회지
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• 제11권1호
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• pp.17-29
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• 1993

As inverstigating the influence of monomers and photoinitiator in the polymerization rate of photopolymerization by using IR spectroscopy, photopolymerizations initiated by ultraviolet radiation are characterized by the presence of an autoacceleration in the polymerization rate as the reaction proceeds. The conversion for the end of the autoacceleration varies considerably depending on the monomer and reaction condition which determines coil size and viscosity. In UV curable systems, the autoacceleration begins at only a few percent conversion and continues to 40% in HEA solution and 60% conversion in EHA solution. The polymerization ate in HEA solution increased as follow; DMHA > HCPK > DMPA and could be explained by the interaction between the initiating radical and HEA monomer and the size of the photodissociated radical of initiator. But the tendency of autoacceleration in EHA solution is almost independent on initiator.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 추계학술대회 논문집 전기물성,응용부문
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• pp.230-233
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• 2002

A new lithium niobate optical modulator with a polymer buffer layer on Ni in-diffused optical waveguide is proposed for the fist time, successfully fabricated and examined at a wavelength of 1.3 ${\mu}m$. The experimental results show that the measured half-wave voltage is of ${\sim}10$ V and the total measured fiber-to-fiber insertion loss is of ${\sim}-6.4$ dB for a 40 mm long waveguide at a wavelength of 1.3 ${\mu}m$, respectively.

• Macromolecular Research
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• 제9권6호
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• pp.313-318
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• 2001

The present study relates to a method of manufacturing 100$\mu\textrm{m}$ thick cover layer for the high density digital versatile disc system (HD-DVD), which uses a high numerical aperture of 0.85 at 405 nm wavelength. Spin coating technique was investigated as means for manufacturing the cover layer within sufficient margins of thickness variation and with good mechanical properties including small radial and tangential tilts. The influence of processing variables such as spinning speed, spinning time, and dispensing position was investigated. The effect of viscosity of UV-curable resin was also investigated.

• Bulletin of the Korean Chemical Society
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• 제33권2호
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• pp.492-498
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• 2012

A hyper branched 10-butylphenothiazine with in-situ thermally curable methacrylate (1,3,5-tris-[$\{$10-Butyl-3-(4-(2-methyl-acryloyloxy)-phenyl)-7-yl-10H-phenothiazine$\}$]-benzene, (tris-PTMA)) was synthesized successfully. From the TGA thermogram of tris-PTMA was thermally stable up to $336^{\circ}C$. In the first heating scan of DSC thermogram, tris-PTMA showed glass transition temperature (Tg) at $140^{\circ}C$ and broad endothermic process in the region of $144-179^{\circ}C$, which is thermally curing temperature. In the second heating process, $T_g$ exhibited at $158.7^{\circ}C$ and endothermic process was not observed. Thermally cured tris-PTMA showed no big change in the UV-visible spectrum after washing with organic solvent such as methylene chloride, chloroform, toluene, indicating that thermally cured film was very good solvent resistance. Thermally cured tris-PTMA was electrochemically stable and the HOMO energy level of tris-PTMA was -5.54 eV. The maximum luminance efficiency of double layer structured polymer light-emitting diode based on in-situ thermally cured tris-PTMA was 0.685 cd/A at 16.0 V, which was higher than that of the device without thermally cured tris-PTMA (0.348 cd/A at 15.0 V).

• 한국세라믹학회지
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• 제56권4호
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• pp.360-364
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• 2019

PZT suspensions for photo-curable 3D printing were fabricated and their characteristics were evaluated. After mixing the PZT, photopolymer, photo-initiator, and dispersant for 10 min by using a high-shear mixer, the viscosity characteristics were investigated based on the powder content. To determine an appropriate dispersant content, the dispersant was mixed at 1, 3, and 5 wt% of the powder and a precipitation test was conducted for two hours. Consequently, it was confirmed that the dispersibility was excellent at 3 wt%. Through thermogravimetric analysis, it was confirmed that weight reduction occurred in the photopolymer between 120? and 500?, thereby providing a debinding heat treatment profile. The fabricated suspensions were cured using UV light, and the polymer was removed through debinding. Subsequently, the density and surface characteristics were analyzed by using the Archimedes method and field-emission scanning electron microscopy. Consequently, compared with the theoretical density, an excellent characteristic of 97% was shown at a powder content of 87 wt%. Through X-ray diffraction analysis, it was confirmed that the crystallizability improved as the solid content increased. At the mixing ratio of 87 wt% powder and 13 wt% photo-curable resin, the viscosity was 3,100 cps, confirming an appropriate viscosity characteristic as a stereolithography suspension for 3D printing.

• Journal of the Optical Society of Korea
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• 제10권3호
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• pp.124-129
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• 2006

We have developed a compact and cost-effective camera module on the basis of wafer-scale-replica processing. A multiple-layered structure of several aspheric lenses in a mobile-phone camera module is first assembled by bonding multiple glass-wafers on which 2-dimensional replica arrays of identical aspheric lenses are UV-embossed, followed by dicing the stacked wafers and packaging them with image sensor chips. This wafer-scale processing leads to at least 95% yield in mass-production, and potentially to a very slim phone with camera-module less than 2 mm in thickness. We have demonstrated a VGA camera module fabricated by the wafer-scale-replica processing with various UV-curable polymers having refractive indices between 1.4 and 1.6, and with three different glass-wafers of which both surfaces are embossed as aspheric lenses having $230{\mu}m$ sag-height and aspheric-coefficients of lens polynomials up to tenth-order. We have found that precise compensation in material shrinkage of the polymer materials is one of the most technical challenges, in orderto achieve a higher resolution in wafer-scaled lenses for mobile-phone camera modules.

• 폴리머
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• 제32권2호
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• pp.138-142
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• 2008

분자 날인 기술은 표적 분자에 대해 높은 선택도를 갖는 합성 재료를 제조하기 위한 효과적인 방법이다. 본 연구에서는 주형 분자로 테오필린(theophylline)을, 가교제로 폴리에스터-아크릴레이트 수지를 사용하여 UV 중합을 통해 분자 날인 고분자(MIP)를 합성하였다. 기능성 단량체 종류가 MIP의 성능에 미치는 영향을 알아보기 위해, 메타크릴산(mathacrylic acid), 아크릴산(acrylic acid), 그리고 아크릴 아미드(acrylic amide)를 기능성 단량체로 각각 사용하여 MIP를 합성하였다. MIP는 비날인 고분자(NIP)보다 테오필린에 대해 훨씬 더 높은 재결합 능력을 보였다. 메타크릴산을 사용하여 합성한 MIP는 가장 높은 재결합 능력을 보였다. MIP의 선택도는 테오필린과 분자구조가 유사한 카페인(caffeine) 용액을 사용하여 조사하였다. 클로로포름보다 극성인 증류수를 용매로 사용하였을 경우 MIP의 테오필린 재결합 성능은 감소하였다.

• 폴리머
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• 제34권6호
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• pp.574-578
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• 2010

본 연구에서는 고리화합물인 카프로락톤으로부터 2-hydroxyethyl acylate(2-HEA)를 개시제로 사용하여 caprolactone modified hydroxy acrylate(CHA)를 합성한 후, hexamethylene diisocyanate trimer(HDT)와 축중합을 통해 카프로락톤 변성 우레탄 아크릴레이트(UA) 올리고머를 합성하였다. 카프로락톤과 2-HEA의 몰비에 따른 CHA의 분자량은 수산가를 이용하여 계산되었으며, 계산된 분자량은 이론분자량과 거의 일치하였다. UA 올리고머의 점도는 2-HEA 대한 CHA의 함량이 증가할수록 감소하는 경향을 보였다. UA 올리고머와 반응형 희석제를 광개시제와 함께 광경화한 후, 형성된 경화필름의 내열성 및 내열 변색성을 측정하였다. 경화필름의 가교밀도가 증가할수록 내열성 및 내열변색성이 우수하였으나 가교밀도가 증가할수록 경도는 증가하지만, 신율은 상대적으로 감소하였다.

• 접착 및 계면
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• 제21권2호
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• pp.58-64
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• 2020

본 연구에서는 UV 경화형 폴리우레탄 아크릴레이트와 실리카 나노입자를 용매에 분산하여 간편한 스프레이 코팅을 통해 초발수 및 초발유 표면을 제작하였다. 용매의 종류, 고분자의 농도, 분사량 조절에 따른 코팅 표면 구조의 변화를 확인하였으며, 물과 오일의 접촉각 측정을 통해 초발수 및 초발유 특성을 정량화 하였다. 스프레이 코팅 표면의 re-entrant 구조를 분석하여 초발수 및 초발유 특성이 극대화된 스프레이 코팅의 메커니즘을 제시하였다. 최적화된 스프레이 코팅 조건을 적용하여 제조된 표면의 물과 오일의 접촉각 hysteresis는 각각 2°, 30° 이하이며 오일 방울이 표면에서 튈 정도로 우수한 초발수 및 초발유 특성을 보였다.