• 제목/요약/키워드: LASER

검색결과 14,379건 처리시간 0.031초

Optimization of a Passively Q-switched Yb:YAG Laser Ignitor Pumped by a Laser Diode with Low Power and Long Pulse Width

  • Kim, Jisoo;Moon, Soomin;Park, Youngin;Kim, Hyun Su
    • Current Optics and Photonics
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    • 제4권2호
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    • pp.127-133
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    • 2020
  • We successfully constructed a passively Q-switched Yb:YAG laser ignitor pumped by a diode laser with low power and long pulse width. To the best of our knowledge, this is the first study to achieve a quasi-MW output power from an optimized Q-switch Yb:YAG laser ignitor by using a pumping diode laser module emitting at under a power of 23 W. The output pulse energy of our optimized laser is 0.98 mJ enclosed in a 1.06 ns pulse width, corresponding to a peak power of 0.92 MW.

구조화 레이저패턴다이오드를 이용한 Robot End-Effector 추적연구 (Study on robot end-effector tracking using structured laser pattern diode)

  • 조재완;이남호;이용범;이종민
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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    • pp.523-526
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    • 1996
  • In this paper, robot endeffector tracking using sensory information from structured laser pattern diode, is described. In order to track robot endeffector robustly irrespective of translation, scaling and rotation of robot working tool, structured laser pattern is used as track feature. Structured laser patterns of crosshair, concentric circles, dot matrix, and parallel lines are illuminated to robot endeffector. Illuminated laser patterns are held invariently and coherently irrespective of various motions of robot endeffector. Extracting and tracking these invariant structured laser patterns as track feature, the whole system keeps tracking of the robot endeffector robustly and effectively provided that structured laser pattern is always assumed to aim at robot endeffector.

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자율주행 로봇을 위한 Laser Range Finder

  • 차영엽;권대갑
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 1992년도 추계학술대회 논문집
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    • pp.266-270
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    • 1992
  • In this study an active vision system using a laser range finder is proposed for the navigation of a mobile robot in unknown environment. The laser range finder consists of a slitted laser beam generator, a scanning mechanism, CCD camera, and a signal processing unit. A laser beam from laser source is slitted by a set of cylindrical lenses and the slitted laser beam is emitted up and down and rotates around the robot by the scanning mechanism. The image of laser beam reflected on the surface of an object is engraved on the CCD array. A high speed image processing algorithm is proposed for the real-time navigation of the mobile robot. Through experiments it is proved that the accurate and real-time recognition of environment is able to be realized using the proposed laser range finder.

아세톤 형광을 이용한 공연비 측정 기법 연구 (An Experimental Investigation of Air Fuel Ratio Measurement using Laser Induced Acetone Fluorescence)

  • 박승재;허환일;오승묵
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2002년도 학술대회지
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    • pp.353-356
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    • 2002
  • Planar laser induced fluorescence(PLIF) has been widely used to obtain two dimensional fuel distribution. Preliminary investigation was performed to measure quantitative air excess ratio distribution in an engine fueled with LPG. It is known that fluorescence signal from acetone as a fluorescent tracer is less sensitive to oxygen quenching than other dopants. Acetone was excited by KrF excimer laser (248nm) and its fluorescence image was acquired by ICCD camera with a cut-of filter to suppress Mie scattering from the laser light. For the purpose of quantifying PLIF signal, an image processing method including the correction of laser sheet beam profile was suggested. Raw images were divided by each intensity of laser energy and profile of laser sheet beam. Inhomogeneous fluorescence images scaled with the reference data, which was taken by a calibration process, were converted to air excess ratio distribution. This investigation showed instantaneous quantitative measurement of planar air excess ratio distribution for gaseous fuel.

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레이저 간섭계를 이용한 이동형 미세 변위 측정에 관한 연구 (A Study on the Portable Micro Displacement Measurement Using Laser Interferometer)

  • 최경현;양형찬
    • 동력기계공학회지
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    • 제10권2호
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    • pp.99-103
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    • 2006
  • The laser interferometer has been used for measurement of the micro displacement error. Although the laser interferometer is widely accepted as a tool for measurement of motion accuracy, the set-up procedure is time-consuming because of the strict requirement on alignment between a laser head and optic units. This paper addresses the development of a laser interferometer to measure the micro displacement for a micro machine. The portable laser interferometer which integrates a laser probe and optics, is developed for the convenient measurement. For the experiment, moving mirror set up on the micro stage. The velocity decoding board is also added to calculate doppler shift frequency directly. The output signal is obtained and analyzed by LabView. Finally experiments are found out the relation between micro displacement and output signal.

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고출력 $CO_2$ 레이저 용접시 포토 다이오드를 이용한 플라즈마와 스패터 모니터링 (Monitoring of plasma and spatter with photodiode in $CO_2$ laser welding)

  • 박현성;이세헌;정경훈;박인수
    • 한국레이저가공학회지
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    • 제2권1호
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    • pp.30-37
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    • 1999
  • Laser-welded Tailored Blank is the hottest thing in many automobile companies. But they demand on weld quality, reproducibility, and formability. So it is the great problem of automation of laser welding process. Therefore, it is requested to construct on-line process monitoring system on high accuracy. The light which is emitted from plasma and spatter in laser welding was detected by photo-diodes. It was found that the light intensity depends on welding speed. laser power, and flow rate of assist gas. The relationship between the plasma and spatter and the weld quality can be used for on-line laser weld monitoring systems.

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레이저 직접묘화법에 의한 AlN 기판상의 전도성 패턴 제작에 관한 연구 (A Study on Fabrication of Conductor Patterns on AlN Ceramic Surface by Laser Direct Writing)

  • 이제훈;서정;한유희
    • 한국레이저가공학회지
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    • 제3권2호
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    • pp.25-33
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    • 2000
  • One of perspective direction of microfabrication is direct laser writing technology that allows to create metal, semiconductive and dielectric micropatterns on substrate surface. In this work, a two step method, the combination of seed forming process, in which metallic Al seed was selectively generated on AlN ceramic substrate by direct writing technique using a pulsed Nd : YAG laser and subsequent electroless Ni plating on the activated Al seed, was presented. The effects of laser parameters such as pulse energy, scanning speed and pulse frequency on shape of Alseed and conductor line after electroless Ni plating were investigated. The nature of the laser activated surface is analyzed from XPS data. The line width of this metallic Al and Ni is analyzed using SEM. As a results, Al seed line with 24㎛ width and 100㎛ isolated line space is obtained. Finally, laser direct writing can be applied in the field between thin and thick film technique in electronic industry.

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시스템적 접근을 통한 레이저 미세가공 설계 프로세스 개발에 관한 연구 (A Study on Application of Systems Approach for Laser Micro Machining Design Process)

  • 문성욱;박영원;남기중
    • 한국레이저가공학회지
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    • 제10권3호
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    • pp.15-24
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    • 2007
  • In this paper laser micromachining system design process for commercialization is suggested. The constructed system design process is properly adjusted for laser micromachining area after tailoring engine process of system engineering process such as requirement analysis, functional analysis and allocation, system synthesis and system optimization process. In the current laser machining system design, system components and specifications are determined on the basis of experimental experience which a laser is being used in machining some materials as well as the current machining and research trend. In this paper, however, systematic process is suggested in addition to experimental experience, which the laser and system components and their specifications are decided in the process of definition of functional requirements and engine design variables of system to satisfy the customer's requirements.

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액상에서의 엑시머 레이저 실리콘 미세가공 (Excimer laser micromachining of silicon in liquid phase)

  • 장덕석;김동식
    • 한국레이저가공학회지
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    • 제11권1호
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    • pp.12-18
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    • 2008
  • Laser micromachining is a promising technique to fabricate the micro-scale devices. However, there remains important challenges to reducethe redeposition of ablated materials around the laser irradiated zone and to get a smooth surface, especially for metal and semiconductor materials. To achieve the high-quality micromachined devices, various methods have been developed. Liquid-assisted micromachining can be a good solution to overcome the previously mentioned problems. During the laser ablation process, the liquid around the solid sample dramatically changes the ablation characteristics, such as ablation rate, surface profile, formation of debris, and so on. In this investigation, we conducted the laser micromachining of Si in various liquid environmental conditions, such as liquid types, liquid thickness. In addition, using nanoscale time-resolved shadowgraphy technique, we observed the ablation process in liquid environments to understand the mechanism of liquid-assisted laser micromachining.

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추출격자 분포 브래그 반사기가 집적된 광대역 파장가변 추출격자 분포 궤환 레이저 다이오드 (A widely tunable sampled-grating distributed feedback laser diode integrated with sampled-grating distributed bragg reflector)

  • 김수현;정영철
    • 한국광학회지
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    • 제15권4호
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    • pp.369-374
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    • 2004
  • 본 논문에서는 새로운 구조의 파장가변 레이저 다이오드를 제안하였다. 제안된 레이저 다이오드는 추출격자 분포궤환 레이저 다이오드와 추출격자 분포 브래그 반사기가 집적된 구조로 되어 있다. 제안된 레이저 다이오드는 특정한 구조에서 27 nm정도의 광대역 파장가변이 가능함을 수치해석을 통해 확인하였다. 또한 이득영역에서 생성된 광파를 다른 수동영역을 거치지 않고 직접 광섬유에 결합시킬 수 있는 구조로 광효율이 기존의 레이저 다이오드에 비해 우수함을 확인하였다.