• 한국정밀공학회지
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• 제27권3호
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• pp.9-17
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• 2010

The FPCB is used for electronic products such as LCD display. The process of manufacturing FPCB includes a cutting process, in which each single FPCB is cut and separated from the panel where a series of FPCBs are arrayed. The most-widely used cutting method is the mechanical punching, which has the problem of creating burrs and cracks. In this paper, the cutting characteristics of the FPCB have been experimented using Nd:YAG DPSS UV laser as a way of solving this problem. To maximize the industrial application of this laser cutting process, test samples of the multilayered FPCB have been chosen as it is actually needed in industry. The cutting area of the FPCB has four different types of layer structure. First, to cut the test sample, the threshold laser cut-off fluence has been found. Various combinations of laser and process parameters have been made to supply the acquired laser cut-off fluence. The cutting characteristics in terms of the variation of the parameters are analyzed. The laser and process parameters are optimized, in order to maximize the cutting speed and to reach the best quality of the cutting area. The laser system for the process automation has been also developed.

• 한국광학회:학술대회논문집
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• 한국광학회 2003년도 제14회 정기총회 및 03년 동계학술발표회
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• pp.234-235
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• 2003

All solid-state UV lasers provide efficient, clean and semipermanent light sources for various applications, such as eye surgery, microchip lithography. $CsLiB_{6}O_{10}$ (CLBO) is one of the most suitable crystals for UV generation because of its small walk-off, large effective nonlinear susceptibility in UV region and high damage threshold. We produced fourth (266 nm) and fifth (213 nm) harmonic generation of an Nd：YAG laser (1064 nm) with $LiB_{3}O_{5}$ as a second harmonic generation medium and CLBO as a fourth harmonic and fifth harmonic mediums. (omitted)

• 한국방사선학회논문지
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• 제14권5호
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• pp.695-703
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• 2020

의료기술 발전으로 인해 의료기기 사용이 증가하는 추세이다. 의료기기 중 이식 및 치료를 위해 인체 내에 사용되는 경우가 많다. 그러므로 의료기관에서는 감염 예방을 위해 의료기기 형태와 재질에 따른 멸균법들이 다양하게 적용되고 있다. 뼈 이식에서 수산화인화석 재료가 가장 많이 보급되어 있다. 소형 의료기기에 알맞은 비전리방사선 중 고출력에너지를 가진 Q-switch Nd:YAG 레이저를 이용한 멸균법을 제시하고자 한다. 대장균과 충치균을 수산화인화석 디스크에 오염시켜, 출력1.5 W, 파장은 각각 자외선(266, 355 nm), 가시광선(532 nm), 적외선(1,064 nm), 1과 10 펄스를 각각 조사하였다, 본 연구에서 자외선 파장인 1.5 W, 266 nm, 10 pulse에서 멸균력을 가장 이상적으로 보여주었다. 다른 파장대인 적외선, 가시광선은 소극적 멸균력을 보였으며, 자외선 A와 자외선 C는 펄스에 따라 멸균 차이를 보였다. 레이저 멸균에서 파장 및 펄스에 따라 멸균 차이를 알 수 있었다.

• 한국광학회:학술대회논문집
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• 한국광학회 2000년도 하계학술발표회
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• pp.108-109
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• 2000

현재 많은 종류의 레이저가 학술적으로나 산업계에서 다양하게 사용되고 있다. 그리고 그 중에서도 자외선 레이저의 필요성이 한층 강조되고 있는 시점이다. 사용되고 있는 자외선 레이저는 Eximer 레이저, Nd:YAG의 제3고조파, 다른 레이저로 펌핑한 색소 레이저등이 그 주류를 이루고 있다. 하지만 이들 레이저들은 값이 아주 고가이거나 그 출력이 매우 낮아 새로운 방식의 레이저를 요구하고 있다. 그래서 본 실험실에서는 여러 용도로 사용 가능한 펄스형 고출력 색소 레이저를 개발하고 있다. (중략)

• 반도체디스플레이기술학회지
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• 제8권4호
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• pp.31-36
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• 2009

In this paper, the laser cutting characteristics of the flexible PCB using high power Nd:YAG UV laser were investigated. A specific FPCB model was selected for the experiment. Test sheets were made, which had equal materials and layer structure to those of the outline (OL) region and the contact pad (CP) region in the FPCB. The experiment is made up of two stages. In the first stage of the experiment, the laser cutting fluence was found, which is the threshold fluence to cut the test sheets completely. The laser cutting fluence of the OL sheet is $1781.26{\sim}1970.16\;J/cm^2$ and that of the CP sheet is $2109.34{\sim}2134.34\;J/cm^2$. In the second stage, cutting performance and its qualities were analyzed by the experiment. The laser cutting performance remained almost unchanged for all laser and process parameter sets. The average cutting width (top side/bottom side) of the OL sheet was $40.45\;{\mu}m/11.52\;{\mu}m$ and that of the CP sheet was $22.14\;{\mu}m/10.93\;{\mu}m$. However, the laser cutting qualities were different according to the parameters. The adjacent region of the cutting line on the OL sheet was carbonized as the beam speed was low and the overlap coefficient was high. The surface quality around the cutting line of the CP sheet was about the same. Carbonization and debris occurred on the surface of the cutting line. As a result of the experiment, the cutting qualities were better as the overlap coefficient was made low and beam speed high. Therefore, the overlap coefficient 2 or 3 is proper for the FPCB laser cutting.

• 한국진공학회지
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• 제6권2호
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• pp.114-121
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• 1997

투명전도성 산화주석 박막이 펄스레이저증착에 의하여 파이렉스유리 기판상에 제조 되었다. 진공, $O_2$, 및 $Sn(CH_3)_4$분위기에서 Nd-YAG레이저 빛살이 다결정 $SnO_2$ 타겟을 융제 하여 실온에서 기판상에 박막을 증착시키고, 증착된 막을 230, 420, 및 $610^{\circ}C$에서 각각 2시 간 동안 공기중에서 열처리하였다. 박막의 특성이 UV-VIS-NIR 분광법과 X-선 회절법에 의하여 조사되고, 전기적 성질이 촉심식법으로 구해진 막의 두께와 함께 사점탐침법에 의하 여 측정되었다. $Sn(CH_3)_4$이 존재할 때 $SnO_2$상들이 실온에서조차 성장되는 것이 관찰되었다. 이는 레이저 융제 동안 발생된 마이크로플라즈마가 전구물질분자의 분해에 중요한 역할을 함을 시사한다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1999년도 추계학술대회 논문집
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• pp.95-98
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• 1999

ZnO thin films on (001) sapphire substrates have been deposited by pulsed laser deposition technique using a Nd:YAG laser with the wavelength of 355 nm. In order to investigate the effect of the deposition conditions on the properties of ZnO thin films at an oxygen pressure of 350 mTorr, the experiment has been Performed at various substrate temperatures in the range of 20$0^{\circ}C$ to $700^{\circ}C$. According to XRD, (002) textured ZnO films of high crystalline quality have been obtained and the intensity of UV emission was the highest at 40$0^{\circ}C$ substrate temperature.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 추계학술대회 논문집
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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.

• 한국광학회지
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• 제16권2호
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• pp.121-127
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• 2005

본 논문에서는 포토폴리머에 기록된 Bragg 회절 격자의 열적 특성을 측정하였다. 532 nm의 Nd:YAG 레이저를 이용하여 DuPont HRF-l50-38 필름에 홀로그램 격자를 기록하고, 온도 노출 조건에 따라 회절효율을 측정하였다. 열 노출 후 홀로그램 기록에서는 $100^{\circ}C$이하에서 $70\%$이상의 높은 회절 효율을 보인 반면 더 높은 온도에서는 급격히 떨어졌다. 홀로그램 기록 후 열 노출에서는 UV 정착 효과에 따라 $100^{\circ}C$까지는 $10\%$ 정도의 효율 증가를 보여주었지만, $120^{\circ}C$이상에서는 홀로그램이 지워지는 현상이 관찰되었다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 춘계학술대회 논문집 디스플레이 광소자 분야
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• pp.125-128
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• 2000

ZnO thin films on silicon substrates have been deposited by pulsed laser deposition technique(PLD). A Nd:YAG laser was used with the wavelength of 355 nm. In order to investigate the effect of oxygen post-annealing treatment on the property of ZnO thin films, deposited film has been annealed at the substrate temperature of $440^{\circ}C$. After post-annealing treatment in the oxygen ambient, the stoichiometry of ZnO film has been characterized be improved which results in higher UV emission intensity of photoluminescence.