• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2008년도 춘계학술대회 논문집
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• pp.329-330
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• 2008

• 한국레이저가공학회지
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• 제18권3호
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• pp.9-13
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• 2015

The development of a reliable, high-power source of mind-IR laser light gives process develop important tool with unique characteristics that will significantly impact a diverse range of applications.

• 한국레이저가공학회:학술대회논문집
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• 한국레이저가공학회 2005년도 추계학술발표대회 논문집
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• pp.114-121
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• 2005

• Journal of Welding and Joining
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• 제31권4호
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• pp.17-22
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• 2013

The excellent beam quality of high power fiber lasers are commonly used for remote welding applications in body job applications. The Welding speed and productivity is unmatched with any other welding technology including resistance spot welding or traditional laser welding. High tooling cost for clamping and bulky safety enclosures are obstacles which are limiting the use. With the newly developed Laser stitch welding gun we have an integrated clamping in the process tool and the laser welding is shielded in a way that no external enclosure is needed. Operation of this laser welding gun is comparable with resistance spot welding but 2-times faster. Laser stitch welding is faster than spot welding and slower than remote welding. It is a laser welding tool with all the laser benefits like welding of short flanges, weld ability of Ultra High Strength steel, 3 layers welding and Aluminium welding. Together with low energy consumption and minimum operation cost of IPG fiber laser it is a new and sharp tool for economic car body assembly.

• 한국융합학회논문지
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• 제11권7호
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• pp.157-162
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• 2020

최근 레이저를 이용하여 환원된 친환경 그래핀 패턴 기술(Laser Induced Graphene, LIG)은 간단하고 효율적으로 원하는 형태로 다양한 기판 위에 패터닝하는 것이 가능하여 신축 유연 전자 소자, 박막 형태의 에너지 저장 소자 등과 같이 새로운 친환경 전자 소자 제작에 많이 활용되고 있다. 이러한 그래핀 패턴 구조를 이용한 전자 소자의 성능과 효용성을 높이기 위해서는 그래핀 고유의 2차원 특성을 유지하면서 가능한 최소한의 선폭을 구현할 수 있는 최적화된 레이저 패터닝 조건에 대한 연구가 필수적이다. 본 논문에서는 최근 레이저 그래핀 패턴 연구에서 많이 사용되는 Ti:sapphire 펨토초 레이저를 이용해서 그래핀 광-열 산화반응을 분석하여 최적화된 그래핀의 최소선폭을 구현하였다. 레이저 에너지의 확산 효과를 최소화하기 위하여 레이저 광강도와 레이저 스캔 속도를 조절하여 최적의 그래핀 특성을 나타내는 패턴을 연구하였으며 18 ㎛의 집속된 빔을 이용하여 최소 30 ㎛의 이차원 그래핀 선폭을 구현하였다.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제22권1호
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• pp.33-42
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• 2000

The purpose of this study was to compare the wound healing process after skin incision using scalpel, $CO_2$ laser and pulsed Nd:YAG laser in rats. After skin on the back was incised 3 cm long, rats were sacrificed at 1, 3, 7, 14, 21 and 28 days. Macroscopic, histologic and immunohistochemical examinations using the collagen type IV and the CD34 antibodies which are necessary to the forming process of new capillary were performed. Results obtained were as follows ; Macroscopically the initial wound healing of the laser group was about $1{\sim}2$ weeks slower than that of the scalpel group. There weren't however any remarkable differences in all groups in 4 weeks after incision. By histologic finding, acute inflammatory cells were more prominent during the initial wound healing in the scalpel group than in the other groups. Epithelialization started in the order of scalpel, $CO_2$ and Nd:YAG laser group after skin incision. By the Masson's trichrome stain, collagen synthesis in the Nd:YAG laser group was more slowly initiated than in the other groups. But it was completed at the $3{\sim}4$ weeks in all groups. Immunohistochemically, collagen type IV and CD34 expression were markedly increased at 2 weeks in the scalpel and $CO_2$ laser group. Meanwhile, in the Nd:YAG laser group, these reactions were observed later tan the other groups. Collagen type IV and CD34 expression were decreased in all groups after 4 weeks. These results suggest that $CO_2$ and Nd:YAG laser showed similar healing process compared with scalpel and a potential substitute for scalpel in skin incision.

• 대한기계학회논문집A
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• 제34권11호
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• pp.1765-1771
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• 2010

MEMS 소자의 공정에서 가공된 비아 홀 품질은 소자의 성능에 가장 중요한 요소의 하나이다. Nd:$YVO_4$ 레이저로 가공한 비아 홀에 대한 레이저 미세가공의 일반적인 특징을 설명하고 그것의 측정에 대한 효율적인 최적화 방법을 소개한다. 본 논문의 최적화 방법은 직교다항식, 분산분석과 반응표면최적화는 최적 레이저 공정변수를 결정하고 주요 영향을 이해하는데 사용된다. 유의한 레이저 공정변수를 확인하고 이의 비아 홀 품질에 관한 영향을 고찰하였다. 레이저 공정변수의 최적 수준을 가지는 확인 실험은 최적화 방법의 유효성을 설명하기 위해 수행하였다.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1997년도 추계학술대회 논문집
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• pp.254-259
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• 1997

The measurement of surface roughness and waviness by means of noncontact method is an important area to be developed for GAC(Geometrical Adaptive Control) system. This paper deal with the design of noncontact in-process measurement system which measures the surface roughness and waviness during cylindrical grinding. This measuring system is simple and the apparatus proposed is composed of a laser unit, photodetector and optical system. During operation, the surface of a workpiece is continuously scanned by a laser beam. This method makes it possible to detect the surface roughness and waviness along the feed direction by control the spot diameter of laser beam. The experimental results show that the presence of chattering, loading and glazing can be detected sensitively along the feed directions.

• 제어로봇시스템학회논문지
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• 제9권12호
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• pp.1048-1054
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• 2003

In laser surface hardening processes, the geometrical parameters such as the depth and the width of a hardened layer can be utilized to assess the hardened layer quality. However, accurate monitoring of the geometrical parameters for on-line process control as well as for on-line quality evaluation is very difficult because the hardened layer is formed beneath a material surface and is not visible. Therefore, temperature monitoring of a point of specimen surface has most frequently been used as a process monitoring method. But, a hardened layer depends on the temperature distribution and the thermal history of a specimen during laser surface hardening processing. So, this paper describes the estimation results of the geometric parameters using multi-point surface temperature monitoring. A series of hardening experiments were performed to find the relationships between the geometric parameters and the measured temperature. Estimation results using a neural network show the enhanced effectiveness of multi-point surface temperature monitoring compared to one-point monitoring.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.234-234
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• 2013

The counter electrodes in dye-sensitized solar cells (DSSCs) play roles in not only collecting electrons from external circuit but also reducing I3- to I- in electrolytes. Generally, conventional counter electrodes for DSSCs are prepared from the high temperature treatment of the H2PtCl6 precursor solution at $400^{\circ}C$ However, the more simplified fabrication process of counter electrodes is required for the commercialization of DSSCs. In this work, we developed novel fabrication process of counter electrodes using nano-second pulsed laser. DSSCs employing counter electrodes prepared by laser process showed conversion efficiency of 6.75% with short-circuit current of 12.73 mA/cm2, open-circuit voltage of 0.74 V and fill factor of 0.72. Closer investigating of photovoltaic properties will be reported.