• Title, Summary, Keyword: laser beam

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Effect of Nd:YVO4 Laser Beam Direction on Direct Patterning of Indium Tin Oxide Film

  • Ryu, Hyungseok;Lee, Dong Hyun;Kwon, Sang Jik;Cho, Eou Sik
    • Journal of the Semiconductor & Display Technology
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    • v.18 no.3
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    • pp.72-76
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    • 2019
  • A Q-switched diode-pumped neodymium-doped yttrium vanadate (YVO4, λ =1064nm) laser was used for the direct patterning of indium tin oxide (ITO) films on glass substrate. During the laser direct patterning, the laser beam was incident on the two different directions of glass substrate and the laser ablated patterns were compared and analyzed. At a low scanning speed of laser beam, the larger laser etched lines were obtained by laser beam incident in reverse side of glass substrate. On the contrary, at a higher scanning speed, the larger etched pattern sizes were found in case of the beam incidence from front side of glass substrate. Furthermore, it was impossible to find no ablated patterns in some laser beam conditions for the laser beam from reverse side at a much higher scanning speed and repetition rate of laser beam. The laser beam is expected to be transferred and scattered through the glass substrate and the laser beam energy is thought to be also dispersed and much more influenced by the overlapping of each laser beam spot.

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A Study on Thermal Analysis of Dual Beam Laser Welding of Thin Metal Sheet (박판의 이중 빔 레이저 용접에서 열유동 해석에 관한 연구)

  • 김재웅
    • Journal of Welding and Joining
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    • v.15 no.4
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    • pp.99-108
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    • 1997
  • Analytical model for the temperature distribution and the cooling rate of weld in dual beam laser welding is presented for investigating the possibility of controling the cooling rate. The model is based on the solutions to the problem of heat flow due to the distributed and line heat sources for preheating and welding respectively in plates with finite thickness. The effects of beam power, beam distribution parameter, interbeam distance, and welding speed on the resulting temperature distribution and cooling rate are presented. The cooling rates of dual beam laser weld at the weld centerline under the investigated conditions are reduced to as one third of those of welds which were produced by single beam laser. And it appeared that the cooling rate of dual beam laser weld is strongly dependent on the process parameters of preheating laser beam power and welding speed.

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Measurement of Spatial coherence function and Directional coherence function of Propagating Laser Beam by using Wigner Distribution Function

  • Lee, Chang-Hyuck;Kang, Yoon-Shik;Noh, Jae-Woo
    • Proceedings of the Optical Society of Korea Conference
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    • pp.449-450
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    • 2009
  • The spatial coherence and propagation property of laser beam propagating through several optical components were studied experimentally by using the measurement of Wigner distribution function. It is shown experimentally that the Wigner function measurement yields total degree of coherence, beam quality parameter, and the near and the far field information of the propagating beam. More complete characterization of the laser beam was achieved by applying the Schmidt mode decomposition to the Wigner distribution function, spatial coherence function and directional coherence function. Fine details of coherence property are understood by the characteristics of the contributing eigenmodes.

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Trend of Laser Beam Welding Technology (고밀도 열원방식 레이저빔 용접의 연구동향)

  • Kim, H.T.;Kil, S.C.
    • Proceedings of the KAIS Fall Conference
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    • pp.481-484
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    • 2011
  • The increasing interest in the laser beam welding is placing stringent demands on the manufacturing techniques and performance requirements, and the manufacture employs the high quality and efficiency laser beam welding technology. This paper covers recent research trends of the laser beam welding technology including the laser beam surfacing and laser beam cladding technology.

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Study of frequency chirping of pulse amplified laser beam by using heterodyne method (헤테로다인 방법을 이용한 펄스 증폭된 레이저빔의 주파수 Chirping연구)

  • 김진태
    • Korean Journal of Optics and Photonics
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    • v.13 no.1
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    • pp.70-72
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    • 2002
  • Amplified pulsed laser beam with narrow linewidth was generated from CW laser beam with narrow linewidth by using frequency doubled Nd:YAG laser beam and Bethune cell. The degree of the frequency chirping of the amplified pulse laser was measured by using the heterodyne method and obtained by calculating instantaneous phase change from heterodyne beating signals. The frequency chirping of amplified pulsed laser beam from CW laser beam with sub-MHz linewidth by 10 ns pulse was 80 MHz so that pulsed laser beam with very narrow linewidth was obtained.

High power $CO_2$ laser beam welding for low carbon steels (저탄소강의 고출력 $CO_2$ 레이저 빔 용접)

  • 김재도
    • Journal of Welding and Joining
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    • v.7 no.4
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    • pp.12-21
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    • 1989
  • Laser beam welding parameters have experimentally investigated, using a continuous wave 3kW $CO_2$ laser with the various travel speeds, beam mode and laser beam power in low carbon steels. An optimum position of focus and the effect of shielding gas on penetration depth with varying the flow range of 0.5 to 5.1m/min have been combined to investigate the effect of laser power and travel speed on penetration depth and bead width. It is found that the optimum position of focus in 3kW class laser is 0.5 to 1.5mm below the surface of the material. The flow rate of shielding gas affects the penetration depth and He is more effective than Ar. The penetration depth in laser welds of low carbon steels is between two and four times of the bead width. Laser beam welding of butt joints in 2mm thick carbon steel has been carried out to establish a weldability lobe. The lobe indicating acceptable welding conditions is introduced.

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Laser Etching Characteristics of ITO/Ag/ITO Conductive Films on Forward/Reverse Sides of Flexible Substrates (플렉서블 기판 전/후면에서의 레이저를 이용한 ITO/Ag/ITO 전극층의 식각 특성)

  • Nam, Hanyeob;Kwon, Sang Jik;Cho, Eou-Sik
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.29 no.11
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    • pp.707-711
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    • 2016
  • ITO/Ag/ITO conductive films on PET (polyethylene terephthalate) was etched by a Q-switched diode-pumped neodymiun-doped yttrium vanadate (Nd:YVO4, ${\lambda}=1064nm$) laser. During the laser direct etching, the laser beam was incident on the two different directions of PET and the etching patterns were investigated and analyzed. At a lower repetition rate of laser pulse, the larger laser etched patterns were obtained by laser beam incident on reverse side of PET substrate. On the contrary, at a higher repetition rate, it was possible to find the larger etched patterns in case of the laser beam incidence on forward side of PET substrate. For the laser beam incidence on reverse side, the laser beam is expected to be transferred and scattered through the PET substrate and the laser beam energy is thought to be dependent on the etch laser pulse beam energy.

$CO_2$ Laser Irradiation Strengthening by Defocused Beam (비집속빔을 이용한 $CO_2$ 레이저 빔 조사강화)

  • Seo, Jung;Lee, Je-Hoon;Kang, Hee-Sin;Kim, Jung-Oh;Lee, Moon-Yong;Oh, Sang-Jin;Lee, Kyu-Hyun
    • Journal of Korean Society of Laser Processing
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    • v.6 no.2
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    • pp.1-7
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    • 2003
  • Defocused CO$_2$ laser beam irradiation strengthening of 60kgf/$\textrm{mm}^2$ grade steel sheet was investigated to obtain the tensile strength similar to that of fully penetrated one by the focused beam. The melted line width by the defocused beam was 3∼4 times larger compared to that of the focused beam. However, the increase of tensile strength with 1 line irradiation by the defocused beam was similar to that of 2~3 lines by the focused beam. The increase(37.6%) of bending strength with 1 line by the defocused beam was higher than the increase(12.9%) of tensile strength. Also, the effect of cooling gas to strengthening was observed.

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Dual Laser Beam Joining Process for Polymers in Automotive Applications to Reduce Weights (차량경량화를 위한 듀얼 레이저 에너지 플라스틱 접합의 응용)

  • Han, Sang Bae;Choi, Hae Woon
    • Journal of Welding and Joining
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    • v.31 no.4
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    • pp.23-27
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    • 2013
  • Laser heat source was used for automotive interior and exterior parts to reduce weights. Typically, 900's nm wavelength of laser has been widely used for polymer joining, however, the transmittance of the laser beam thorough clear polymers such as PMMA or PC has been an issue to overcome. To solve this issue, 1,940nm laser was applied on the clear polymer for the better absorption and 900nm laser beam was used for main laser for the joining. Conventional Gaussian or Elliptical heat source approximation has limitation in polymer which had deeper skin depth where major laser beam absorbs. To accurately simulate the physical laser beam absorption and joining optical properties were experimentally measured for the computer FEM simulation. The simulation results showed close correlation between theoretical and experimental results. The developed laser process is expected to increase productivity and gap closing which can cause failure of joining in laser material processing.

Study on Characteristics of Micro Patterned Copper Electrodeposition according to Parameters in Laser Beam Machining (레이저빔 가공 인자에 따른 구리도금 미세 패터닝 특성 연구)

  • Shin, Hong Shik
    • Journal of Institute of Convergence Technology
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    • v.5 no.2
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    • pp.21-25
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    • 2015
  • This paper proposes a fabrication process of deposited layer with micro patterns that uses a combination of a pulsed laser beam machining and an electrodeposition. This process consists of the electrodeposition and the laser beam machining. The deposited layer on metal can be selectively eliminated by laser ablation. As a result, the deposited layer with micro patterns can be fabricated without a mask. The characteristics of the deposited layer on stainless steel were investigated according to the average power and marking speed in the pulsed laser beam machining. The optimal laser beam conditions for precise micro patterning of the deposited layer were determined. Finally, the deposited copper layer with micro text was successfully fabricated by the pulsed laser beam machining.