• 마이크로전자및패키징학회지
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• 제6권3호
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• pp.51-63
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• 1999

무기 충전제를 고충전시킨 에폭시 수지 조성물이 반도체 패키지의 신뢰성에 미치는 영향을 검토하였다. Ouchiyama 등의 모델로부터 최대충전밀도를 향상시킴으로써 고충전을 달성할 수 있는 방법을 제시할 수 있었으며, 최대충전밀도가 증가함에 따라 에폭시 수지 조성물의 점도가 감소하였고, 흐름성이 개선되었다. 충전제 함량이 증가함에 따라 흡습 특성이 향상되었고 열팽창계수를 낮춤으로써 저응력화를 달성할 수 있었으나, 임계 충전제 함량 이상에서는 금속 리드프레임과의 접착강도가 저하되었다. 따라서 에폭시 수지 조성물의 균형 있는 신뢰 특성을 얻기 위해서는 충전제 함량을 적정하게 선택해야 하며, 충전량을 더욱 높여 고신뢰성을 얻기 위해서는 최적의 충전제 조합을 선정하여야 함을 알 수 있었다.

• 한국태양에너지학회 논문집
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• 제34권2호
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• pp.44-52
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• 2014

The main purpose of this paper is to develop the new BIPV module equipped with vacuum glass. Beacuse BIPV module has a function of architectural materials, thermal and PV performance should be simultaneously evaluated. To improve the thermal performance of BIPV module, this study developed BIPV module equipped with a vacuum glass. Those BIPV module was tested with a variety of encapsulants. The results are as follows. When a vacuum glass is laminated with EVA or PVB, it was broken. The reason seems to be bending by unbalance of heat expansion with center and edge of vacuum glass. In case of lamination with resin, there is no breakage and no bending of vacuum glass. Because production was conducted in low pressure & low temperature conditions. And it was also found that vacuum glass does not interfere with the UV curing process.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.1108-1109
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• 2008

To survive in outdoor environments, photovoltaic modules rely on packaging materials to provide requisite durability. We analyzed the properties of encapsulant materials that are important for photovoltaic module packaging. Recently, the thickness of solar cell gets thinner to reduce the quantity of silicon. And the reduced thickness make it easy to be broken while PV module fabrication process. Solar cell's micro cracks are increasing the breakage risk over the whole value chain from the wafer to the finished module, because the wafer or cell is exposed to tensile stress during handling and processing. This phenomenon might make PV module's maximum power and durability down. So, when using thin solar cell for PV module fabrication, it is needed to optimize the material and fabrication condition which is quite different from normal thick solar cell process. Normally, gel-content of EVA sheet should be higher than 80% so PV module has long term durability. But high gel-content characteristic might cause micro-crack on solar cell. In this experiment, we fabricated several specimen by varying curing temperature and time condition. And from the gel-content measurement, we figure the best fabrication condition. Also we examine the crack generation phenomenon during experiment.

• 조명전기설비학회논문지
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• 제26권7호
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• pp.1-8
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• 2012

In this paper, we improved the light extraction efficiency by structural change of LEDs on conventional LEDs. We simulated the LEDs light emission as functions of LED side wall angle, various refractive indices the geometrical structures and analyzed the condition improved the light efficiency. We present the results of experimerns and simulations for light output power from LEDs for various refractive indices and the geometrical structures of the LED encapsulants. When the side wall angle range was from 40[$^{\circ}$] to 30[$^{\circ}$], the LED emission increased. LED side wall angle onto LED using the simulation system with a fine tuning of the structure of the LEDs side wall angle is fabricated. Additionally, we changed the side wall angle of LED package with spherical structure and flat structure. The result of spherical structure ray tracting is higher compared with flat structure about 14[%].

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2011년도 추계학술발표대회 논문집
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• pp.45-50
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• 2011

The efficiency of solar cell was about 4[%] in initial stage of photovoltaic industry, but it has quite a lot of efficiency through technology advances. Today, the efficiency of c-Si solar cells is about 17 to 19[%] and the efficiency of PV modules is about 14 to 15 [%]. We called that electrical losses occurred in the Conversion of solar cells to PV modules are CTM loss(Cell To Module loss), the CTM loss typically has a value of about3~5[%]. The more efficiency of solar cell increase, differences are larger because the efficiency decrease owing to physical or technical problems occurred in the Conversion of solar cells to PV modules. In this study, the power loss factors occurred in the Conversion of solar cells to PV modules are analyzed and it is proposed that how to reduce losses of the PV module. The types of power loss factor are (1)losses of front glass and encapsulant(generally EVA sheet), (2)losses by sorting miss, (3)losses by interconnection, (4)losses by the field aging of PV modules. In further study, experimental and evaluation will be conducted to make demonstrate for proposed solutions.

• 신재생에너지
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• 제17권2호
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• pp.24-31
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• 2021

Renewable energy has become more popular with the increase in the use of solar power. Consequently, the disposal of defective and old solar panels is gradually increasing giving rise to a new problem. Furthermore, the efficiency and power output decreases with aging. Researchers worldwide are engaged in solving this problem by developing eco-module technologies that restore and reuse the solar panels according to the defect types rather than simple disposal. The eco-module technology not only solves the environmental problem, but also has economic advantages, such as extending the module life. Replacement of encapsulants contributes to a major portion of the module maintenance plan, as the degradation of encapsulants accounts for 60% of the problems found in modules over the past years. However, the current International Electrotechnical Commission (IEC) standard testing was designed for the commercialization of solar modules. As the problem caused by long-term use is not considered, this method is not suitable for the quality assurance evaluation of the eco-module. Therefore, to design a new accelerated test, this paper provides an overview of EVA degradation and comparison with the IEC and accelerated tests.

• 한국태양에너지학회 논문집
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• 제35권5호
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• pp.57-65
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• 2015

The Potential Induced Degradation(PID) in PV module mainly affected by various performance conditions such as a potential difference between solar cell and frame, ambient temperature and relative humidity. The positive charges as sodium ions in front glass reach solar cell in module by a potential difference and are accumulated in the solar cell. The ions accelerate the recombination of generation electrons within solar cell under illumination, which reduces the entire output of module. Recently, it was generally known that PID generation is suppressed by controlling the thickness of SiNx AR coating layer on solar cell or using Sodium-free glass and high resistivity encapsulant. However, recovery effects for module with PID are required, because those methods permanently prevent generating PID of module. PID recovery method that voltage reversely applies between solar cell and frame contract to PID generation begins to receive attention. In this paper, PID recovery tests by using voltage under various outdoor conditions as humidity, temperature, voltage are conducted to effectively mitigate PID in module. We confirm that this recovery method perfectly eliminates PID of solar cell according to repeative PID generation and recovery as well as the applied voltage of three factors mainly affect PID recovery.

• Korea-Australia Rheology Journal
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• 제19권3호
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• pp.157-164
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• 2007

Microencapsulation of cells within microfluidic devices enables explicit control of the membrane thickness or cell density, resulting in improved viability of the transplanted cells within an aggressive immune system. In this study, living cells (3T3 and L929 fibroblast cells) are encapsulated within a semi-permeable membrane (calcium crosslinked alginate gel) in two different device designs, a flow focusing and a core-annular flow focusing geometry. These two device designs produce a bead and a long microfibre, respectively. For the alginate bead, an alginate aqueous solution incorporating cells flows through a flow focusing channel and an alginate droplet is formed from the balance of interfacial forces and viscous drag forces resulting from the continuous (oil) phase flowing past the alginate solution. It immediately reacts with an adjacent $CaCl_2$ drop that is extruded into the main flow channel by another flow focusing channel downstream of the site of alginate drop creation. Depending on the flow conditions, monodisperse microbeads of sizes ranging from $50-200\;{\mu}m$ can be produced. In the case of the microfibre, the alginate solution with cells is extruded into a continuous phase of $CaCl_2$ solution. The diameter of alginate fibres produced via this technique can be tightly controlled by changing both flow rates. Cell viability in both forms of alginate encapsulant was confirmed by a LIVE/DEAD cell assay for periods of up to 24 hours post encapsulation.

• 마이크로전자및패키징학회지
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• 제7권3호
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• pp.37-44
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• 2000

Electrochemical impedance spectroscopy (EIS)를 이용하여 에폭시 수지 조성물이 코팅된 알루미늄 패드의 부식거동을 연구하였다. 에폭시 수지 조성물은 반도체 패키지 봉지용으로써 80 wt%의 충전재를 포함하고 있으며, $100^{\circ}C$의 끊는 가혹 조건에서 탈이온수 (deionized water)를 사용하여 에폭시 조성들에 침투시켰다. 흡습이 진행되면서 에폭시 조성물 및 알루미늄/에폭시 계면에서의 저항 감소와 커패시턴스 증가가 관찰되었으며 , 약 170 시간까지는 물분자와 유기물로부터 발생된 이온이 에폭시 조성물에 포화되고, 그 이후에는 계면에 침투하여 금속의 부식을 발생시키는 것을 알 수 있었다. 수분 흡습에 따른 에폭시 조성물/금속간의 접착강도 측정으로부터 계면에 물분자 및 이온이 포화됨에 따라 접착강도가 감소하는 것을 예상할 수 있었으며, 반도체 패키지용 에폭시 수지 조성물에 의한 알루미늄 전극의 부식을 방지하기 위해서는 충전재의 함량증가가 필수적이라는 것을 알 수 있었다.

• 폴리머
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• 제39권2호
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• pp.311-316
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• 2015

고경도의 LED 봉지재로 치밀한 구조를 가지는 polyhedral oligomeric silsesquioxane(POSS)를 첨가제로 사용한 실리콘 젤을 제조하였다. 실록산 수지와의 상용성을 증가시키기 위하여 알킬기와 올리고실록산기를 가지로 갖는 POSS를 합성하였다. Hydrosilylation 반응을 통하여 가지와 POSS를 연결하였고, 1-decanol과 9-decen-1-ol의 반응에는 $H_2PtCl_6$을, 말단에 비닐기를 가지는 올리고실록산의 반응에는 1,3-divinyl tetramethyldisiloxane[Pt(dvs)]을 촉매로 사용하였다. 알킬기를 가지는 POSS(Decyl-POSS, Decenyl-POSS)를 사용한 실리콘 젤의 경우 실록산 수지와의 혼화성이 낮아서, 가시광선 영역의 투과도가 낮았으며 경도값도 낮았다. 이에 비해 올리고실록산기를 가지로 가지는 POSS(Siloxy-POSS)를 적용하였을 경우에는 실록산 수지와 혼화성이 우수하여 높은 투명도를 보였으나, POSS의 첨가로 인한 경도 증가는 뚜렷하게 나타나지 않았다.