• Information Display
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• v.7 no.2
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• pp.10-13
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• 2006

Active Matrix Flat Panel Display(AM-FPD)의 경쟁력 향상을 위해서 반드시 필요한 고성능, 고생산성 Thin Film Transistor(TFT)를 제작에 사용하는 결정화 방법 중, 산업화에 가장 근접한 레이저 결정화 방법 및 장비에 대해서 기술한다.

• Proceedings of the KIEE Conference
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• 1987.07a
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• pp.51-53
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• 1987

• Laser Solutions
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• v.15 no.3
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• pp.1-6
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• 2012

The friction force of patterned needle in elastomer have been investigated to verify the application for bio and plastic industry. The micro pattern on the needle surface were prepared by 266 nm, 20 ns laser and 800 nm, 220 fs laser, which were able to generate the different surface roughness. The friction force was measured by the load cell of 10 N capacity. As the results, the friction force of no patterned needle is almost constant during the needle penetrates the silicone rubber sample. However, the needle having asperities shows the variation of the friction force. The higher the surface roughness is, the smaller the friction force is until the surface roughness is very high. In our experiment conditions, the reduction of the friction force by 20 % compared to no pattern needle was achieved with straight and $50{\mu}m$ discrete line generated by 266 nm, 20 ns laser.

• Journal of the korean academy of Pediatric Dentistry
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• v.27 no.1
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• pp.169-179
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• 2000

The purpose of this study is to develop the system which convert the optical difference of teeth texture between intact enamel and incipient caries lesion into shade difference by laser fluorescence and to develop new and simple caries activity test using laser fluorescence. The experimental design of this study consists of three parts. In first part, a new method for the in vitro assessment of changes in initial enamel caries lesion of Bovine teeth using laser fluorescence is tested. In second part, in vivo assessment undertaken. Number of teeth which showed incipient carious lesion on buccal surface examined by laser fluorescence was compared with the caries activity test of $Cariescreen^{(R)}$ test and other oral environmental test of dDfFtT. In third part, new caries activity test measured by laser fluorescence was developed on the basis of above results and evaluated the sensitivity, specificity, and diagnostic power. Optical density measured by laser fluorescence was increased as increasing the depth of incipient carious lesion and showed high correlation$(\gamma=0.7015)$ with lesion depth. Optical density showed direct proportion to lesion depth. Linear equation was obtained between the optical density and the lesion depth by regression analysis. The result of caries activity test with laser fluorescence showed high correlation with those of $Cariescreen^{(R)}$ test and dDfFtT examination. Caries activity test with laser fluorescence showed 48% of sensitivity, 52% of specificity, and 45% of diagnostic power on the basis of dDfFtT examination, and also showed 48% of sensitivity, 51% of specificity, and 36% of diagnostic power on the basis of $Cariescreen^{(R)}$ test. In regard above result, caries activity test with laser fluorescence considered to be reliable for caries activity test compared with other oral environmental test. and it was also considered to be practical because it would be simple, inexpensive, and time saving method.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1995.04a
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• pp.313-317
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• 1995

최근 환경오염이 심각한 사회문제로 대두됨에 따라 환경오염원을 제거하기 위한 여러 가지의 집진장치가 개발되고 있는데 화력발전소에서는 건식정전집진장치(dry electrostatic precipitator)를 이용하고 있다. 건식정전집진장치는 햄머(hammer) 방식의 충격장치를 설치하여 집진극과 방전극에 충격을 가함으로써 충격력을 극대화시키고 높은 분진박리 효과를 꾀하고 있는데 환경오염원이 되고 있는 집진판의 분진의 분리율을 높이기 위해서는 집진판의 전체 영역에서 분진을 동일하게 떨어뜨릴 수 있는 충격장치가 설계되어야 하는데, 이를 위해서는 충격하중에 따른 집진판의 진동 형태를 정확하게 분석하여야 한다. 본 연구에서는 집진판의 충격하중에 따른 진동의 형태를 분석하기 위해 펄스 레이저를 이용한 2중 노출 홀로그래피 시스템을 구성하였다. 홀로그래픽 간섭계는 이미 오래 전에 개발된 레이저 응용 계측기법으로서 주로 정현적인 진동을 하는 진동체의 진동 현상을 연구하는 데에 많이 사용되어 왔는데 그 기술 개발은 상당한 수준에 있다. 그러나 종래의 기술들은 주로 헬륨-네온(He-Ne)레이저와 같은 연속 레이저(continuous wave laser)를 이용한 기술들인데 최근에는 루비(ruby) 레이저와 같은 펄스 레이저 (pulse laser)를 이용한 기술이 많이 응용되고 있다. 이 펄스 레이저 홀로그래픽 간섭계를 Gottenberg는 응력파에 의해서 발생된 변형을 측정하기 위해 사용하였고 Aprahamian등은 보(beam)와 평판의 굽힘파(bending wave)의 전파 특성 연구에 이용하였다. 그 실험적 결과는 수치적 해석 결과와 비교되어 매우 좋은 일치성을 보였는데 이러한 펄스 레이져 홀로그래픽 간섭계 기법의 주요 장점은 어떠한 특정한 순간에 관찰하고자 하는 시험편의 전체 영역의 파동 전파 형상을 관찰할 수 있다는 것이다. 따라서 본 연구에서는 펄스 레이저를 응용한 2중 노출 홀로그래피법(double exposure holography method)을 이용해서 집진판에 충격하중이 가해졌을 때 발생하는 진동이 발생과 전파 특성을 충격하중의 방향에 따라서 분석하였다.

• Korean Journal of Optics and Photonics
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• v.19 no.2
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• pp.132-139
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• 2008

In scanning laser optical tweezers, high speed scanning stages are used to manipulate a laser beam spot. Due to the inertia of the stage, the output scanning signal decreases with increased frequency of the input signal. This discrepancy in the signals is difficult to observe since most of the energy from the laser beam is blocked out to avoid CCD damage. In this paper, we propose two methods to alleviate these problems. Firstly, frequency responses of piezo stages are measured to analyze the signal drops and the input signal is compensated accordingly. Secondly, an overlay of the scanning path is drawn on the live monitoring screen to enhance the visibility of the scanning path. The result is a drop-compensated scanning with clear path view.

• Journal of the Korean Society of Radiology
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• v.14 no.5
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• pp.695-703
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• 2020

The use of medical devices is increasing due to the development of medical technology. Among medical devices, it is often used in the human body for graft and treatment. Therefore, in medical institutions, various sterilization methods according to the type and material of medical devices are applied to prevent infection. Hydrophosphite (HA) materials are the most popular in bone grafts. We would like to present a sterilization method using Q-switch Nd:YAG laser with high output energy among non-ionizing radiation suitable for small medical devices. In this study, sterilization power was most ideally shown at UV wavelengths of 1.5 W, 266 nm, and 10 pulses. Different wavelength bands; infrared and visible light; showed passive sterilization, and ultraviolet A and C showed differences in sterilization according to the pulse. In laser sterilization were differences that found according to the wavelength bands and pulses.

• KIISE Transactions on Computing Practices
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• v.21 no.3
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• pp.247-256
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• 2015

Since the Gulf War, air power has played a key role. However, the effect of high-tech weapons, such as laser-guided bombs and electronic optical equipment, drops significantly if they do not match the weather conditions. So, aircraft that are assigned to carry laser-guided bombs must replace these munitions during bad weather conditions. But, there are no objective criteria for when weapons should be replaced. Therefore, in this paper, we propose an algorithm to predict the hit rate of laser-guided bombs using cloud image processing. In order to verify the accuracy of the algorithm, we applied the weather conditions that may affect laser-guided bombs to simulated flight equipment and executed simulated weapon release, then collected and analyzed data. Cloud images appropriate to the weather conditions were developed, and applied to the algorithm. We confirmed that the algorithm can accurately predict the hit rate of laser-guided bombs in most weather conditions.

• Proceedings of the Optical Society of Korea Conference
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• 2002.07a
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• pp.78-79
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• 2002

눈의 시력을 진단하는 도구 또는 장비로는 자각식 측정법인 시력표, 타각식 계측기로는 검영기와 자동굴절력측정기 등이 있다. 이들 방법으로 얻는 결과는 시력 또는 굴절력 값으로 제한된다. 그러나 인체안도 일반 광학계와 같이 공간적으로 불균일한 광학적 특성을 가지기 때문에, 눈의 광학적 기능을 정확하게 진단하기 위해서는 공간에 따른 광학수차 분포를 측정할 필요가 있다. 특히 엑시머레이저를 이용한 굴절각막교정수술에서, 광학수차 정보는 정교한 교정수술을 위한 기초 자료가 될 수 있다. (중략)

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.10a
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• pp.783-784
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• 2012