• 한국광학회지
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• 제15권2호
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• pp.171-176
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• 2004

광 편향기가 집적된 레이저 다이오드를 제작하고 편향기 주입전류에 따른 레이저 다이오드의 특성 변화 및 출력광의 편향을 조사하였다. 레이저 다이오드와 집적된 수동 도파로의 상부 클래드 층의 일부분에 광 편향기를 집적하고, 편향기의 전류 주입에 따른 굴절률 변화를 유도하여 출력광의 편향이 발생하도록 하였다. 편향기의 전류 주입에 따른 출력광의 특성변화를 조사하기 위하여 편향기 주입 전류에 따른 레이저 다이오드의 문턱 전류(threshold current), 발진 효율(slope efficiency) 및 출력광 스펙트럼을 측정하였다. 측정 결과, 편향기 전류의 증가에 따라 출력광의 문턱 전류는 증가하고, 발진 효율은 감소하는 경향을 나타내었으나 출력광의 스펙트럼에는 영향을 주지 않는 특성을 나타내었다. 또한, 이론적 계산을 통해 광 편향기를 지나는 광이 편향됨을 확인하고, 편향기 집적 레이저 다이오드에서 출력되는 광의 far-field pattern을 측정하여 편향기 주입 전류에 따른 출력광의 편향을 실험적으로 확인하였다. 제작된 광 편향기 집적 레이저 다이오드에서 15 ㎃의 광 편향기 주입 전류 변화에 대해서 1.9$^{\circ}$의 편향각 변화를 측정 할 수 있었다.

• 폴리머
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• 제35권1호
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• pp.1-6
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• 2011

사출성형은 고온의 수지를 고압으로 금형에 충전하고 냉각하여 제품을 만드는 공정으로 큰 온도차이와 고압에 의해 성형품에 잔류응력이 형성된다. 이러한 잔류응력은 시간이 지남에 따라 이완되면서 제품에 변형을 일으켜 형상 품질을 저하시킨다. 본 연구에서는 광탄성 장치를 이용하여 투명한 사출성형품의 잔류응력을 측정하는 방법을 연구하였다. 빛은 전자파처럼 진행하는데 편광필름을 통과하면 하나의 파장만이 진행하게 된다. 그 파장이 시편을 통과하면서 시편에 존재하는 잔류응력 때문에 복굴절이 형성되고 두 번째 편광필름을 통과하면서 다양한 색의 패턴을 보이게 된다. 이 색의 패턴을 이용하여 사출성형으로 제작된 사각평판의 잔류응력을 정량적으로 측정하였다. 또한 컴퓨터 해석을 통해 사출성형품의 광학적 특성을 예측하였으며 실험과 비교하였다.

• 소성∙가공
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• 제14권7호
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• pp.624-627
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• 2005

In this paper, we investigated the possibility of replicating patterned media by nano-injection molding process with a metallic nano-stamper. The original nano-master was fabricated by I-beam lithography and ICP etching process. The metallic nano-stamper was fabricated using a nanoimprint lithography and nano-electroforming process. Finally, the nano-patterned substrate was replicated using a nano-injection molding process without additional etching process. The replicated patterns using nano-injection molding process were as small as 50nm in diameter, 150nm in pitch, and 50nm in depth.

• 소성∙가공
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• 제21권2호
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• pp.126-130
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• 2012

Accurate optical texturing of light guide plate over the entire surface area is an important technical issue in LCD TV industry. Injection molding process has the potential to produce large light guide plates having highly efficient optical textures such as micro-prism array. This study is focused on the effect of the degree of replication of the micro texture of the 40" injection molded light guide plates on the overall optical performance of the display panel. Measured replication ratios of the micro-textures formed with three different types of injection molding process were considered in the modeling of prismatic micro segment array. Optical simulation was conducted and results were discussed.

• Structural Engineering and Mechanics
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• 제52권3호
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• pp.541-558
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• 2014

A 1/4-scale two-bay eight-storey reinforced concrete frame was tested on shaking table. Initial shaking table tests were carried out through a set of real seismic excitations to investigate the seismic behavior of the RC frame. Subsequently, the damaged frame was repaired using epoxy injection technique, and then subjected to the tests with the same records. The purpose of this study was to investigate experimentally the dynamic characteristics, cracking pattern and lateral inter-story stiffness of RC frames using epoxy injection technique. The test results indicate that epoxy-injection technique appears to be a satisfactory method for repairing earthquake-damaged structure.

• 소성∙가공
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• 제14권6호
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• pp.570-576
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• 2005

Powder Injection Molding(PIM) has recently been recognized as an advanced manufacturing technology for low-cost mass production of metal or ceramic parts of complicated geometry With this regards, design technology of dental scaler tip PIM mold, which has complex shape and small core pin (diameter=0.6mm), with the help of computer-aided analysis of powder injection molding process was developed. Computer-aided analysis for dental scaler tip mold was implemented by finite element method with non-Newtonian fluid, modified Cross model viscosity, PvT data of powder/binder mixture. Compter-aided analysis results, such as filling pattern, weldline formation, air vent position prediction were compared with experimental result, and eventually have been shown good agreement. The core pin (diameter=0.6mm) deflection analysis of dental scaler tip PIM mold during PIM filling process was also investigated before mold fabrication.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2005년도 춘계학술대회 논문집
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• pp.60-63
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• 2005

In this paper, we investigated the possibility of replicating patterned media by nano-injection molding process with a metallic nano-stamper. The original nano-master was fabricated by E-beam lithography and ICP etching process. The metallic nano-stamper was fabricated using a nanoimprint lithography and nano-electroforming process. Finally, the nano-patterned substrate was replicated using a nano-injection molding process without additional etching process. The replicated patterns using nano-injection molding process were as small as 50 nm in diameter, 150 nm in pitch, and 50 nm in depth.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2006년도 춘계학술대회 논문집
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• pp.95-98
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• 2006

LCD-BLU (Back Light Unit) is one of kernel parts of LCD unit. The fabrication method of a 3-D micro mold patterned with micro-lenses for the LGP (Light Guiding Plate), one of the most important parts of LCD-BLU, was presented. Instead of dot pattern made by etching, 3-D optical pattern design with $50{\mu}m$ micro-lens was applied in the present study. The micro-lens pattern fabricated by modified LiGA with thermal reflow process was applied to the optical design of LGP. The positive micro-lens patterned injection mold with different aspect ratios (i.e. 0.3 and 0.4) was fabricated with modified LiGA with thermal reflow process. The brightness of LCD-BLU increased as aspect ratio of micro-lens increased.

• 한국표면공학회지
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• 제53권4호
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• pp.138-143
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• 2020

In this study, we produced a coil of micro-pattern that can be used for electromagnetic wave absorber, heating material, wireless charging, sensor, antenna, etc. by using electrochemical additive manufacturing method. Currently, it contains research contents for manufacturing a micro pattern coil having practicality through control of process control variables such as applied voltage, distance between electrode, and nozzle injection. Circulation of the electrolyte through the nozzle injection control can significantly contribute to improving the surface characteristics of the coil because of minimizing voltage fluctuations that may occur during the additive manufacturing process. In addition, by applying the pulse method in the application of voltage, the lamination characteristics of the plated body were improved, which showed that the formation of a fine line width plays an important role in the production of a micro pattern coil. By applying the pulse signal to the voltage application, the additive manufacturing characteristics of the produced product were improved, and it was shown that the formation of a fine line width plays an important role in the production of a micro pattern coil.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2008년도 춘계학술대회 논문집
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• pp.269-272
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• 2008

LGP is a key component of LCD back light unit because it determines the brightness and sharpness of display image. Usually, it has optical patterns fabricated on the bottom surface. In the present paper the LiGA-reflow method was applied to fabricate the LGP mold. Furthermore, the optical simulation considering the replication ratio of pattern height was applied to the pattern design. The optical simulation through systematic correction scheme helped find the optimum distribution of pattern density. Finally, the stamper fabricated by this method was installed in the mold and LGP was produced by injection molding. As a result of luminance measurement for the final product, the average luminance and luminance uniformity was measured 3,180 nit and 84%, respectively. Consequently, the mold fabrication method using the LiGA-reflow and optical simulation(CAE) can save the expense and time compared with the existing fabrication methods(laser ablation and chemical etching).