• 한국레이저가공학회지
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• 제14권3호
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• pp.1-6
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• 2011

Globally, the interest of renewable energy has become an upsurge. Especially, the solar industry is the one which is getting rapid growth rate. Many of researchers have been undertaking to improve the efficiency of solar cell to accomplish grid parity. The most of research has been concentrated on two methods, one on the selective emitter and the other is on LBSF (Local Back Surface Field) formation. Laser patterning will be needed to eliminate the thin film to form selective emitter and LBSF of solar cell. This paper reports some experimental results in laser patterning process for high-efficiency crystalline solar cell manufacturing. The experimental results indicate that the patterning quality depends on the average power and repetition rate of laser. The experimental results prove that the laser patterning process is an advantageous method to improve the efficiency of solar cell.

• 한국레이저가공학회지
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• 제18권4호
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• pp.1-5
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• 2015

For continuous laser micro patterning on three-dimensional free form surface, innovative laser system is developed. The two axis galvanometer is combined with the dynamic focusing unit to increase optical distance. Also, it is synchronized with the 3 axis mechanical system. To determine laser machining sequence, laser CAM system is developed. It can make possible of 3D surface micro patterning under $25{\mu}m$ pattern width. The uniformity of pattern width is about 2.8% and it is validated that focal plane is well conserved by the dynamic focusing unit. Velocity and positional information of 1 axis is stage is fed to the scanner control board by the encoder signal and it makes possible real time synchronization. With this system, possible patterning volume is enlarged from $40{\times}40mm^2$ to $40{\times}120{\times}30mm^3$.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2004년도 추계학술대회 논문집
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• pp.369-372
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• 2004

Photo-induced surface alignment is charming as a non-contact photo-patternable alignment technology which can be used in the next generation of displays, such as large area, multi-domain. For decades, many polymer film have been investigated and developed to be used in the photo alignment. Among these photoreactive materials, recently developed polyimide, Chloromethylated Polyimide(CMPI) now became the focus of interests in this area because of its high photosensitivity and superior thermal stability. In this report, we present micro patterning method to form the nanoscale structure by Mask-Less laser patterning using this CMPI film and NSOM probe.

• 한국생산제조학회지
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• 제21권1호
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• pp.116-122
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• 2012

The purpose of this study is on the development of 3-D conductive pattern fabrication system using laser. For development 3-D direct patterning system, we used the dynamic focusing, the laser power stabilizer and the auto aligning techniques. These technologies are already used commercially. However operation and control integrated system for 3-D direct patterning are not yet developed. The objective of this paper is to introduce laser direct structuring and develop the operating and integration system. Also we implemented new application of laser direct structuring.

• 한국레이저가공학회지
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• 제14권3호
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• pp.7-11
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• 2011

As an active emission display using emissive polymer has had much attention recently, needs for a selective patterning of emissive layer for those displays have been increased abruptly. Therefore, the various laser sources in terms of its wavelength has been used for laser direct patterning. In this work, the feasibility of those processes is examined using numerical analysis and the experimental investigation. A sample has multi-layered structure, emissive polymer on aluminum which is deposited on a glass substrate. Key factors for optimizing the laser patterning of the emissive polymer are considered into the control of ablation products, large-sized particle, and the choice of the appropriate wavelength for minimizing the heat affected zone and the remnant layer.

• 한국레이저가공학회지
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• 제8권1호
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• pp.39-44
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• 2005

We report experimental results on the periodic patterning using a Ti:sapphire femtosecond laser (800nm, 100fs, 1kHz). Periodic structures with reproducible basic patterns are produced both on the surface and inside transparent materials. Period patterning for the application to display panel is widely investigated. Also, the submicron dot and line patterns are fabricated inside fused silica glass, which is important for the formation of diffraction grating in integrated optical circuit. finally, we demonstrate the utility of the femtosecond laser application to optical memory by fabricating the three-dimensional dot patterns.

• 한국포장학회지
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• 제29권2호
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• pp.111-118
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• 2023

본 연구에서 연속형 레이저와 나노초 레이저의 경우에는 고분자와 물성 조건이 맞지 않아서, 고분자 필름 표면에 특정 패터닝이 구현되지 않았다. 그러나, 펨토초 레이저를 활용하여 HDPE, PP, PET 등의 식품포장 필름의 표면에 패터닝이 구현됨을 확인하였다. 따라서, 본 연구에서 식품포장 필름에서 펨토초 레이저 패터닝 공정 조건을 확립하였고, 싱글 펄스에 의한 대면적 원형 패턴, 싱글 펄스를 30%를 중첩한 대면적 거칠기 패턴, 직선 패턴, 직선 패터닝을 중첩한 대면적 거칠기 패턴, 직선 패터닝을 교차하여 격자 패턴 등의 표면 패터닝 필름을 제작하였다. 또한, 표면 패턴 구조와 크기에 따른 패터닝 HDPE, PP, PET 필름은 SEM, AFM, 접촉각 분석을 통하여 그 특성을 확인하였다. 펨토초 레이저 패터닝을 하지 않은 각 대조군 필름의 표면 대비 대면적 원형 패터닝 HDPE 및 PP 필름, 싱글 펄스를 30%를 중첩한 대면적 거칠기 패터닝 및 직선 패터닝을 중첩한 대면적 거칠기 패터닝 PET 필름의 표면은 27.1-37.5°의 접촉각을 나타냄으로써, 패터닝 후에 HDPE, PP, PET 필름은 친수성 표면으로 변화되었다. 반면, 나노-마이크로 크기의 돌기 표면구조를 갖고 있는 대면적 격자 패터닝 HDPE 필름의 경우에는 120.4°의 접촉각을 보임으로써, 패터닝 후에 소수성 표면으로 변화되었다. 따라서, 패터닝을 통해 친수성 표면으로 바뀐 필름들은 단백질, 세포, 바이러스 등을 비롯하여 식품의 물질들이 달라붙지 못하거나, 쉽게 떨어지는 엔티파울링 응용분야에 활용이 가능하다. 또한, 향후 좀더 정밀한 나노 및 마이크로 돌기 구조를 갖는 격자 패터닝을 통해 150° 이상의 초소수성 표면을 제작하게 된다면, 자가 청소(Self-cleaning) 등의 초소수성 표면 응용분야에 활용 가능할 것이다.

• 한국전기전자재료학회논문지
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• 제13권6호
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• pp.538-544
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• 2000

The laser patterning of sputter-deposited CoNdZr/Cu/CoNbZr multi-layered films had been tried using Nd:YAG laser. However generally it is very difficult to remove metal films because of their high reflectance of the laser on the surfaces. As a counterproposal for this problem authors for the first time tried to deposit energy-absorbing layers on the metal films and then irradiated the laser on the surfaces of energy-absorbing layers. Here the energy-absorbing layers consisted of laser energy-absorbing fine powders and binding polymers. Three kinds of powders for the energy-absorbing layers had been used to see the difference in the pattern formation with the degree of laser energy absorption. They were electrically conductive silver powders insulating BaTiO$_3$powder and semiconducting carbon powder. Remarkable difference in width of the formed pattern and the roughness of pattern edge were observed with the characteristic of the powder for the energy-absorbing layer. The pattern width using carbon paste was about three times larger than that using BaTiO$_3$paste. It was observed that the energy-absorbing layer with carbon was the most effective on this micro-patterning.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2006년도 추계학술대회 논문집
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• pp.509-510
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• 2006

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2005년도 금형가공,미세가공,플라스틱가공 공동 심포지엄
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• pp.54-58
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• 2005

Femtosecond laser is the latest generation pulsed laser delivering shortest pulses. Any solid materials can be machined by it. Femtosecond laser micromachining allows highest precision and minimal heat influence within the workpiece. But due to the complex physical phenomena between the laser beam and the workpiece materials, it is very difficult to determine the optimal process conditions in the femtosecond laser micromachining. In this study, a method to simulate the femtosecond laser micromachining process was proposed. And femtosecond laser micro patterning processes of chromium thin film are simulated by the proposed method using a commercial FE code, LS-Dyna. Simulation results were compared with those of experiments.