• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.10a
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• pp.887-890
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• 1997

Recently micromachining using DPSSL(Diode Pumped Solid State Laser) with 3rd harmonic wavelength is actively studied in laser machining area. Micromachining using DPSSL have outstanding advantages as UV source comparing with excimer laser in various aspect such a maintenance cost, maskless machining, high repetition rate and so on. In this study micro-drilling of PCB type substrate which consists of Cu-PI-Cu layer was performed using DPSS Nd:YAG laser(355nm, wavelength) in vector scanning method. Experimental and numerical method(Matlab simulation, FEM) are used to optimize process parameter and control machining depth. The man mechanism of this process is laser ablation. It is known that there is large gap between energy threshold of copper and that of PI. Matlab simulation considering energy threshold of material is performed to effect of duplication of pulse and FEM thermal analysis is used to predict the ablation depth of copper. This study could be widely used in various laser micromachining including via hole microdrilling of PCB, and micromachining of semiconductor components, medical parts and printer nozzle and so on.

• Korean Journal of Optics and Photonics
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• v.14 no.3
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• pp.312-320
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• 2003

The basic mechanistic aspects of the interaction and practical considerations related to polymer ablation were briefly reviewed. Photochemical and photothermal effects, which highly depend on laser wavelength have close correlation with each other. In this study, multi-scanning laser ablation processing of polymer with a DPSS (Diode Pumped Solid State) 3rd harmonic Nd:YVO$_4$ laser (355 nm) was developed to fabricate a three-dimensional micro shape. Polymer fabrication using DPSSL has some advantages compared with the conventional polymer ablation process using KrF and ArF laser with 248 nm and 193 nm wavelength. These advantages include pumping efficiency and low maintenance cost. And this method also makes it possible to fabricate 2D patterns or 3D shapes rapidly and cheaply because CAD/CAM software and precision stages are used without complex projection mask techniques. Photomachinability of polymer is highly influenced by laser wavelength and by the polymer's own chemical structure. So the optical characteristics of polymers for a 355 nm laser source is investigated experimentally and theoretically. The photophysical and photochemical parameters such as laser fluence, focusing position, and ambient gas were considered to reduce the plume effect which re-deposits debris on the surface of substrate. These phenomena affect the surface roughness and even induce delamination around the ablation site. Thus, the process parameters were tuned to optimize for gaining precision surface shape and quality. This maskless direct photomachining technology using DPSSL could be expected to manufacture tile prototype of micro devices and molds for the laser-LIGA process.

• Proceedings of the Optical Society of Korea Conference
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• 2002.07a
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• pp.70-71
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• 2002

다이오드 여기 고체레이저(DPSSL, Diode-Pumped Solid State Laser)는 레이저 마킹기, 미세가공기, Ti：sapphire 및 각종 레이저 매질 여기, 의료기기, 그리고 군사용 계측기 등에 다양하게 사용되고 있다. 이러한 응용분야들에 효과적으로 사용되기 위해서는 레이저 출력, 빔모드, 펄스폭, 파장 등이 응용분야에 적합하도록 설계되어야 하며, 고반사율을 갖는 금속의 가공 및 마킹, 그리고 몇가지 레이저 매질의 여기원으로 사용되기 위해서는 짧은 펄스폭과 고품질을 갖는 녹색 파장의 DPSSL 개발이 필요하다. (중략)

• The Optical Journal
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• s.100
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• pp.26-29
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• 2005

레이저 가공기 세계시장은 2010년에 약 70억 달러 이상의 규모가 예상되고 고출력 CW 고체 레이저 시장은 2010년까지 매년 약 30%의 성장이, 펄스레이저 시스템 및 레이저마킹기 시장는 연간 10% 이상의 성장을 예상하고 있다. 반면, 세계 레이저 발진기의 시장에서 CO2 레이저의 경우 시장의 규모가 작아져서 2004년에 약 4억 달러의 규모가 2010년에는 약 2.3억 달러 수준으로 하향할 것으로 예상되고 있다. 고체 레이저에서 특기할 사항은 2010년에 Lamp Pumped CW Nd;YAG 레이저의 경우 약 74백만 달러로 규모가 축소됨에 비해 고출력 DPSSL(Diode Pumped Solid State laser) 시장규모는 약 17억 달러로 급성장하며 레이저 마킹 및 미세 정밀 가공용 저출력 DPSSL의 시장 규모가 약 13억 달러로 고속 성장할 것으로 예측이 된다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.616-619
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• 2003

Photochemical and photothermal effects have correlation with each other and depend on laser wavelength. Multi-scanning laser ablation process of polymer with DPSS(Diode Pumped Solid State) 3rd harmonic Nd:YVO$_4$ laser with wavelength of 355nm is applied to fabricate three-dimensional micro shape. The DPSSL photomachining system can rapidly and cheaply fabricate 2D pattern or 3D shape with high efficiency because we only use CAD/CAM software and precision stages instead of complex projection mask. Photomachinability of polymer is highly influenced by laser wavelength and its own chemical structure. So the optical characteristics of polymers for 355nm laser source is investigated by experimentally and theoretically.

• Photonics industry news
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• s.2
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• pp.30-31
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• 2001

20여년 동안 지속해 온 레이저 개발 및 레이저분공기술 분야에 대한 연구를 지속적으로 추진하고 있는 이종민 한국광학회 회장. 이 회장은 최근 주된 관심사는 고출력 DPSSL (Diode-laser Pumped Sclid-state Laser)레이저, 원적외선 자유전자레이저, 그리고 레이저의 원자력 응용에 관한 연구들이라 말한다. 특히 이 분야들은 이미 5년 전부터 착수된 연구들로서 특히 레이저의 고출력화 및 전고체화 (all-solid-state)에 집중적인 노력을 아끼지 않는다고 또한 그는 인터넷 홈페이지를 통해서 산업 현장의 어려운 목소리를 듣고 직접 해당 전문가의 자문을 받을 수 있는 창구를 개설할 계획이다. 이를 통해 광기술관련 자료의 데이터베이스를 정립하고 지식정보 교환의 장을 구축하여 기초 학문의 실용화를 앞당기며, 기술인력의 정보교환도 자연스럽게 이루워지도록 할 것이며 이러한 사업이 성공적으로 이루어지면 학회와 산업계 모두에게 보람있는 일이 될 것이라고 밝혔다.

• Journal of Powder Materials
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• v.15 no.1
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• pp.46-52
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• 2008

The restrictor, which is a fluid channel from a reservoir to a chamber inside a thermal micro actuator, has been fabricated using ArF and KrF excimer lasers, Diode-Pumped Solid State Lasers (DPSSL) and femtosecond lasers for a feasibility study. A numerical model of fluid dynamics for the actuator chamber and restrictor is presented. The model includes bubble formation and growth, droplet ejection through nozzle, and dynamics of fluid refill through the restrictor from a reservoir. Since an optimized and well-fabricated restrictor is important for a high frequency actuator, some special beam delivery setups and post processing techniques have been researched and developed. The effects of variations of the restrictor length, diameter, and tapered shapes are simulated and the results are analyzed to determine the optimal design. The numerical results of droplet velocity and volume are compared with the experimental results of a cylindrical-shaped actuator. It is found that the micro actuators having tapered restrictors show better high frequency characteristics than those having a cylindrical shape without any notable decrease of droplet volume. The laser-fabricated restrictors demonstrate initial feasibility for the laser direct ablation technique although more development is required.