• 한국레이저가공학회지
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• 제13권1호
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• pp.11-15
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• 2010

Indium tin oxide (ITO) provides high electrical conductivity and transparency in the visible and near IR (infrared) wavelengths. Thus, it is widely used as a transparent electrode for the fabrication of liquid crystal displays (LCDs) and organic light emitting diode displays (OLRDs), photovoltaic devices, and other optical applications. Lasers have been used for removing coating on polymer substrate for flexible display and electronic industry. In selective removal of ITO layer, laser wavelength, pulse energy, scan speed, and the repetition rate of pulses determine conditions, which are efficient for removal of ITO coating without affecting properties of the polymer substrate. ITO coating removal with a laser is more environmentally friendly than other conventional etching methods. In this paper, pattering of ITO film from polymer substrates is described. The Yb:KGW femtosecond laser processing system with a pulse duration of 250fs, a wavelength of 1030nm and a repetition rate of 100kHz was used for removing ITO coating in air. We can remove the ITO coating using a scanner system with various pulse energies and scan speeds. We observed that the amount of debris is minimal through an optical and a confocal microscope, and femtosecond laser pulses with 1030nm wavelength are effective to remove ITO coating without the polymer substrate ablation.

• 한국광학회지
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• 제4권2호
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• pp.181-187
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• 1993

펄스형 파장가변 색소레이저를 사용하여 550~600nm 사이의 파장영역에서 Ne 원자의 OG(Optogalvanic) 스펙트럼을 구했다. 정확하게 알려진 전이에 해당하는 OG 신호의 파장을 기준 위치로 하여 색소 레이저의 파장을 측정하였다. 파장의 정확도는 ${\pm}$0.005nm이며, 각각의 OG 신호의 위치와 상대적인 세기를 표로 만들어 R-590, R-610 색소레이저 파장측정에 이용할 수 있도록 하였다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2005년도 지반공학 공동 학술발표회
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• pp.165-173
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• 2005

Generally, the instrumentation scheme for urban excavation projects consist of a series of tools such as inclinometer piezometer, loadcell, tiltmeter etc. Because almost every equipments are placed along several typical lines, it is impossible to evaluate the whole behavior of structures and adjacent buildings simultaneously. With laser scanning technique developed for surveying, all visible structures are scanned in the form of 3D digital data in a time schedule as planned. It can be analysed effectively the movements for all area affected by excavation even the spots in where no instrumentation tools. Although there are some parts to be refined such as scanning error, proper analysing software, it gives many advantages for realistic instrumentation works in the near future.

• Journal of Welding and Joining
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• 제22권6호
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• pp.43-49
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• 2004

In this study, a visual sensor system which can detect I-butt weld joint with height variation and includes a seam tracking algorithm was investigated. Three-dimensional position of an object can be acquired by using the method of distance measurement, i.e., an optical trigonometry which results from the spatial relations between the camera, the object and the structured light by a visible laser. Effects of laser intensity and iris number for the image quality as well as object material were investigated for the optical system design. For the image processing, a region of interest is defined from the whole image and a line image of laser is drew by using the gray level difference in the image. From the drew laser line, the weld joint can be recognized in searching the biggest point position calculated from the central difference method. Through a series of welding experiments, a good tracking performance was confirmed under GMA welding.

• 대한기계학회논문집A
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• 제26권9호
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• pp.1727-1735
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• 2002

The usage of beam scanning type laser marker is rapidly increasing in the field of semiconductor equipment. A device called ″beam adjuster″ is employed to adjust the visible diode laser, which points the marking position for various setting. The device is very sensitive to manufacturing tolerance and assembly condition. Axiomatic approach has been applied to the design of the device. An existing design is analyzed based on the Independence Axiom. The existing design is found to violate the axiom. Two new designs are proposed to satisfy the Independence Axiom. The Information Axiom is utilized to evaluate the designs. A design is selected to have the minimum information content. The significance of this research is that a full cycle of axiomatic design is applied to a real engineering product.

• 제어로봇시스템학회논문지
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• 제9권12호
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• pp.1048-1054
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• 2003

In laser surface hardening processes, the geometrical parameters such as the depth and the width of a hardened layer can be utilized to assess the hardened layer quality. However, accurate monitoring of the geometrical parameters for on-line process control as well as for on-line quality evaluation is very difficult because the hardened layer is formed beneath a material surface and is not visible. Therefore, temperature monitoring of a point of specimen surface has most frequently been used as a process monitoring method. But, a hardened layer depends on the temperature distribution and the thermal history of a specimen during laser surface hardening processing. So, this paper describes the estimation results of the geometric parameters using multi-point surface temperature monitoring. A series of hardening experiments were performed to find the relationships between the geometric parameters and the measured temperature. Estimation results using a neural network show the enhanced effectiveness of multi-point surface temperature monitoring compared to one-point monitoring.

• Bulletin of the Korean Chemical Society
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• 제31권4호
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• pp.798-802
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• 2010

From time-resolved optical emission spectra, we have investigated the effects of a transverse magnetic field on the expansion of a plasma plume produced by laser ablation of a ZnO:$P_2O_5$ ceramic target in oxygen active atmosphere. The emission spectra of $Zn^{+*}$, $P^{+*}$, and $Zn^*$ neutrals in the presence of magnetic field turn out to be considerably different from those without magnetic field. The characteristics of the deposited films grown on amorphous fused silica substrates by pulsed laser deposition (PLD) are examined by analyzing their photoluminescence (PL), X-ray diffraction (XRD), and UV-visible spectra.

• 세라미스트
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• 제10권3호
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• pp.86-90
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• 2007

Novel photochromic oxide glasses are presented in this section. These glasses are based on phosphate formers containing both tungsten and antimony atoms. Exposure to visible continuous or pulsed laser beam results in an intense photochromic effect witch is shown to occur in the volume of the glass and results in a broad absorption band in the visible and near infrared. This effect was not identified to be related with a structural change and is assumed to be entirely electronic. A change in the absorption coefficient is observed in function of tungsten content, exposure time and increases with beam power. These glasses have been investigated regarding the possibility of holographic data storage using visible lasers sources. Changes in both refractive index and the absorption coefficient were measured using a holographic setup. The modulation of the optical constants is reversible by heat treatment.

• 한국진공학회:학술대회논문집
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• 한국진공학회 1999년도 제17회 학술발표회 논문개요집
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• pp.102-102
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• 1999

Visible photoluminescence(PL) in si-implanted SiO2 films on crystaline silicon were observed. Thermal oxide films of 1 ${\mu}{\textrm}{m}$ thickness on P-type crystal silicon were made and si+ ions were implanted with 200keV acceleration voltage on ti. Argon laser (wavelength 488nm) and PM tube were used for PL measurements. As annealing time increased at low temperature, the visible PL intensity are increased and the peak positions are changed. On the other hand, with increasing annealing time at high temperature, the visible PL intensity are disappeared. From the PL peaks and intensity changes, XRD results, and TEM observations, we will discuss the origin of PL in Si+-implanted SiO2 films with oxygen righ defects and silicon rich defects.

• 디지털콘텐츠학회 논문지
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• 제8권4호
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• pp.425-430
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• 2007

본 논문에서는 주파수 자원의 고갈로 인하여 차세대 무선 정보통신으로 사용의 가능성이 예상되는 가시광 소자를 조명, 신호기, 전광표시, 표시 등에 이용하여, 발광효율의 가시 광 반도체가 조명이나 표시에 이용되어지는 경향이 있고 거기다 고속으로 점멸 가능한 능력을 갖는 것이나 이을 이용한 가시광 통신의 무선 통신에의 응용과 표준화 기술에 대하여 알아보고자한다.