• Title/Summary/Keyword: Laser Beam Energy

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A study on the design of the laser marking system using galvanometer scanner (갈바노미터 스캐너를 이용한 레이저 마킹 시스템 설계 제작에 관한 연구)

  • 조태익;이건이
    • 제어로봇시스템학회:학술대회논문집
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    • 1986.10a
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    • pp.145-148
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    • 1986
  • To perform the marking on metal with high speed and non-contact using the laser beam of high energy, laser marking system is designed and fabricated applying the galvanometer scanner capable of high speed-precise beam positioning controlled by microprocessor. Laser is a Q-switched Nd:YAG producing multi-mode, wavelength, 1060nm. Optical system is composed of beam expander, scanning mirror and flat field lens. Consequently, the laser marking is satisfactorily achieved regardless of kinds of metal.

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Fabrication of embedded circuit patterns for Ie substrates using UV laser (UV 레이저 응용 반도체 기판용 임베디드 회로 패턴 가공)

  • Sohn, Hyon-Kee;Shin, Dong-Sig;Choi, Ji-Yeon
    • Laser Solutions
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    • v.14 no.1
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    • pp.14-18
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    • 2011
  • Semiconductor industry demands decrease in line/space dimensions of IC substrates. Particularly for IC substrates for CPU, line/space dimensions below $10{\mu}m/10{\mu}m$ are expected to be used in production since 2014. Conventional production technologies (SAP, etc.) based on photolithography are widely agreed to be reaching capability limits. To address this limitation, the embedded circuit fabrication technology using laser ablation has been recently developed. In this paper, we used a nanosecond UV laser and a picosecond UV laser to fabricate embedded circuit patterns into a buildup film with $SiO_2$ powders for IC substrate. We conducted SEM and EDS analysis to investigate surface quality of the embedded circuit patterns. Experimental results showed that due to higher recoil pressure, picosecond UV laser ablation of the buildup film generated a better surface roughness.

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Surface Transformation Hardening for Rod-shaped Carbon Steels by High Power Diode Laser (고출력 다이오드 레이저(HPDL)를 이용한 탄소강 환봉의 표면변태경화)

  • Kim, Jong-Do;Kil, Byung-Lea;Kang, Woon-Ju
    • Journal of Advanced Marine Engineering and Technology
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    • v.31 no.8
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    • pp.961-969
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    • 2007
  • The laser material processing has replaced a conventional material processing such as a welding, cutting, drilling and surface modification and so on. LTH(Laser Transformation Hardening) is one branch of the laser surface modification process. A lot of energy is needed for the LTH process to elevate workpiece surface to temperature of the austenite transformation($A_3$), which results from utilizing a beam with a larger size and lower power intensity comparatively. The absorptivity of the laser energy with respect to material depends on the wave length of a beam. This study is related to the surface hardening for the rod-shaped carbon steel by the high power diode laser(HPDL) whose beam absorptivity is better than conventional types of lasers such as $CO_2$ or Nd:YAG laser. Because a beam proceeds on the rotating specimen the pretreated hardened-phase can be tempered and softened by the overlapping between hardened tracks. Accordingly, the longitudinal hardness measurement and observation of the micro structure was carried out for an assessment of the hardening characteristics. In addition, a hardening characteristics as a hardenability of materials was compared in the point of view of the hardness distribution and hardening depth and width.

Defects Length Measurement Using an Estimation Agorithm of the Camera Orientation and an Inclination Angle of a Laser Slit Beam (레이저 슬릿 빔의 경사각과 카메라 자세 추정 알고리듬을 이용한 벽면결함 길이측정)

  • Kim, Young-Hwang;Yoon, Ji-Sup;Kang, E-Sok
    • Journal of Institute of Control, Robotics and Systems
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    • v.8 no.1
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    • pp.37-45
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    • 2002
  • A method of measuring the length of defects on the wall and restructuring the defect image is proposed based on the estimation algorithm of a camera orientation, which uses the declination angle of a laser slit beam. The estimation algorithm of the horizontally inclined angle of CCD camera adopts a 3-dimensional coordinate transformation of the image plane where both the laser beam and the original image of the defects exist. The estimation equation is obtained by using the information of the beam projected on the wall and the parameters of this equation are experimentally obtained. With this algorithm, the original image of the defect can be reconstructed as an image normal to the wall. From the result of a series of experiments, the measuring accuracy of the defect is measured within 0.5% error bound of real defect size under 30 degree of the horizontally inclined angle. The proposed algorithm provides the method of reconstructing the image taken at any arbitrary horizontally inclined angle as the image normal as the wall and thus, it enables the accurate measurement of the defect lengths by using a single camera and a laser slit beam.

Defect Length Measurement using Underwater Camera and A Laser Slit Beam

  • Kim, Young-Hwan;Yoon, Ji-Sup
    • 제어로봇시스템학회:학술대회논문집
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    • 2003.10a
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    • pp.746-751
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    • 2003
  • A method of measuring the length of defects on the wall of the spent nuclear fuel pool using the image processing and a laser slit beam is proposed. Since the defect monitoring camera is suspended by a crane and hinged to the crane hook, the camera viewing direction can not be adjusted to the orientation that is exactly perpendicular to the wall. Thus, the image taken by the camera, which is horizontally rotated along the axis of the camera supporting beam, is distorted and thus, the precise length can not be measured. In this paper, by using the LASER slit beam generator, the horizontally rotated angle of the camera is estimated. Once the angle is obtained, the distorted image can be easily reconstructed to the image normal to the wall. The estimation algorithm adopts a 3-dimensional coordinate transformation of the image plane where both the laser slit beam and the original image of the defects exist. The estimation equation is obtained by using the information of the beam projected on the wall and the parameters of this equation are experimentally obtained. With this algorithm, the original image of the defect taken at arbitrary rotated angle can be reconstructed to an image normal to the wall. From the result of a series of experiments, the accuracy of the defect is measured within 0.6 and 1.3 % error bound of real defect size in the air and underwater, respectively under 30 degree of the inclined angle of the laser slit beam generator. Also, the error increases as the inclined angle increases upto 60 degree. Over this angle, the defect length can not be measured since the defect image disappears. The proposed algorithm enables the accurate measurement of the defect length only by using a single camera and a laser slit beam.

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The Waveform Model of Laser Altimeter System with Flattened Gaussian Laser

  • Ma, Yue;Wang, Mingwei;Yang, Fanlin;Li, Song
    • Journal of the Optical Society of Korea
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    • v.19 no.4
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    • pp.363-370
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    • 2015
  • The current waveform model of a laser altimeter is based on a Gaussian laser beam of fundamental mode, while the flattened Gaussian beam has many advantages such as nearly constant energy distribution on the center of the cross-section. Following the theory of the flattened Gaussian beam and the waveform theory of the laser altimeter, some of the primary parameters of the received waveform were derived, and a laser altimetry waveform simulator and waveform processing software were programmed and improved under the circumstance of a flattened Gaussian beam. The result showed that the bias between theoretical and simulated waveforms was less than 3% for every order mode, the waveform width and range error would increase as target slope or order number rose. Under higher order mode, the shapes of the received waveforms were no longer Gaussian, and could be fitted more precisely as a generalized Gaussian function with power bigger than 2. The flattened beam got much better performance for a multi-surface target, especially when the small surface is far from the center of the laser footprint. This article provides the waveform theoretical basis for the use of a flattened Gaussian beam in a laser altimeter.

Characteristics of direct laser micromachining of IC substrates using a nanosecond UV laser (나노초 UV 레이저 응용 IC 기판 소재 조성별 가공 특성)

  • Sohn, Hyon-Kee;Shin, Dong-Sig;Choi, Ji-Yeon
    • Laser Solutions
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    • v.15 no.3
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    • pp.7-10
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    • 2012
  • Dimensions (line/space) of circuits in IC substrates for high-end chips (e.g. CPU, etc.) are anticipated to decrease as small as $10{\mu}m/10{\mu}m$ in 2014. Since current etch-based circuit-patterning processes are not able to address the urgent requirement from industry, laser-based circuit patterning processes are under active research in which UV laser is used to engrave embedded circuits patterns into IC substrates. In this paper, we used a nanosecond UV laser to directly fabricate embedded circuit patterns into IC substrates with/without ceramic powders. In experiments, we engraved embedded circuit patterns with dimensions (width/depth) of abut $10{\mu}m/10{\mu}m$ and $6{\mu}m/6{\mu}m$ into the IC substrates. Due to the recoil pressure occurring during ablation, the circuit patterning of the IC substrates with ceramic powders showed the higher ablation rate.

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Laser- Plume Effects on Radiation Energy Transfer in Materials Processing (레이저 가공시 에너지 전달과 Plume 효과)

  • Kang, Kae-Myung;Kim, Kwang-Ryul
    • Korean Journal of Materials Research
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    • v.12 no.1
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    • pp.27-35
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    • 2002
  • In laser materials processing, localized heating, melting and evaporation caused by focused laser radiation forms a vapor on the material surface. The plume is generally an unstable entity, fluctuating according to its own dynamics. The beam is refracted and absorbed as it traverses the plume, thus modifying its power density on the surface of the condensed phases. This modifies material evaporation and optical properties of the plume. A laser-produced plasma plume simulation is completed using axisymmetric, high-temperature gas dynamic model including the laser radiation power absorption, refraction, and reflection. The physical properties and velocity profiles are verified using the published experimental and numerical results. The simulation results provide the effect of plasma plume fluctuations on the laser power density and quantitative beam radius changes on the material surface. It is proved that beam absorption, reflection and defocusing effects through the plume are essential to obtain appropriate mathematical simulation results. It is also found that absorption of the beam in the plume has much less direct effect on the beam power density at the material surface than defocusing does and helium gas is more efficient in reducing the beam refraction and absorption effect compared to argon gas for common laser materials processing.

Assessment of Spatial Filter for Gaussian Beam (가우시안빔에 대한 공간파수여과기 성능평가)

  • 홍경희
    • Proceedings of the Optical Society of Korea Conference
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    • 1989.02a
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    • pp.76-80
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    • 1989
  • Spatial filters were designed for 1 TW high power phosphate glass laser development. Laser beam should be expanded from 1 mm diameter to 200mm diameter. Pin hole size should be determined and most of incident energy should be transmitted through out to final spatial filter. Each pin hole size is determined by calculating encircled energy for Gaussian beam from the oscillator. The optical tube length of each spatial filter is corrected to have the best collimating quality by scew raytracing through the total system.

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A Study on Thermal Diffusivity Measurement by Improvement of Laser Flash Uniformity Using an Optical Fiber (광섬유를 이용한 레이저섬광의 균일분포 증진효과에 따른 열확산계수 측정에 관한 고찰)

  • Lee, Won-Sik;Bae, Shin-Chul
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.22 no.8
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    • pp.1073-1082
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    • 1998
  • When thermal diffusivity is measured by laser flash method, the thermal diffusivity call be calculated front the assumption of the uniformly heated whole surface of the specimen. It has been known that the approximate 5% error is made by the non-uniform energy distribution on the specimen surface of laser pulse heat source. In this study, to obtain the highly-uniformed laser beam, which has both the low non-uniform heating error from non-uniform laser beam and the energy loss, research was carried out on no transmitting loss by optical fiber and high repetitions. In addition, heating error and thermal diffusivity were measured as the measuring positions were varied and compared with the results using the uniform and the non-uniform laser beams. In addition, dole to using the uniformalized laser beam, the whole surface of the specimen was heated uniformly and as a result, it was the thought that this was very effective to reduce the variations of the errors of the thermal diffusivity as the measuring positions were varied. It can be obtained that when the thermal diffusivity of POCO-AXM-5Q1 of SRM in NBS was measured with both the uniform and the non-uniform laser beams, the dispersion error of the former was from 2 to 2.5%, which was more improved than that of the latter.