• 한국광학회지
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• 제16권1호
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• pp.50-55
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• 2005

기준광과 탐사광의 경로길이가 매우 크게 차이가 나는 경로길이 불일치 간섭계(unequal path interferometer)를 이용한 직경 300mm 카세그레인 형태의 인공위성 망원경과 같은 대구경 광학계의 변조전달함수(modulation transfer function : MTF)와 파면오차를 동시에 측정하는 방법을 제안하고 이를 실험적으로 확인하였다. 이러한 경로불일치 간섭계를 이용한 측정시스템에서 필요한 평행한 시준광을 만들기 위해서 쌍방향 층밀리기 간섭계를 사용하였으며, 파면오차를 측정하기 위해서 직경 400 mm인 비축 포물경을 사용하는 긴 광경로차의 대구경 피조우 간섭계를 사용하였다. 또한 회전하는 확산판을 이용하여 레이저 광을 부분가간섭광으로 바꿈으로써 피조우 간섭계의 파장으로부터 쉽게 MTF를 측정할 수 있었다.

• 한국기계가공학회지
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• 제5권2호
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• pp.22-26
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• 2006

This paper addresses the development of a laser interferometer to measure micro displacement for a micro system. The laser interferometer is able to measure micro displacement during a few micro seconds with non-contact. In order to employ the interferometer, the displacement calibration experiment should be required. For the experiment, a laser probe installed on the optical table with optical devices and a micro stage. The velocity decoding board is also added to calculate doppler shift frequency directly. The output signal is processed by LabView. Finally experiments are found out the relation between displacement and output signal.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2001년도 춘계학술대회 논문집
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• pp.114-118
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• 2001

HP Laser Interferometer Measurement System[HP5529A] is one of the most powerful equipment for measurement of the motion accuracy. The straightness measurement system of the HP5529A is composed of wollastone prism and reflector. In this system, straightness error is measured by relative lateral motion between prism and reflector. But rotating motion of prism or reflector as moving optic causes not real straightness error but additive straightness error. Especially unwanted straightness error as this becomes very large when reflector is used as moving optic and an interval between reflector and prism is distant. In this paper, the compensation method is proposed for removing additive error and experiment is carried out for theoretical verification.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 추계학술대회 논문집
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• pp.214-219
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• 1997

We propose a new scheme of high-resolution heterodyne interferometer that employs the two-axial mode He-Ne laser with an inter-mode beat frequency of 600-1000 MHz. An electronic RF-heterodyne circuit lowers the beat frequency down to 5 MHz, so that the phase change of the interferometer output is precisely measured with a displacement resolution of 0.1 nanometer without significant loss of dynamic bandwidth. A thermal control scheme is adopted to stabilize the cavity length with aims to suppress frequency drifts caused by the phenomena of frequency pulling and polarization anisotropy of the two-axial mode laser to a stability level of 2 parts in $10^9$. The two-axial mode HeNe laser yields a high output power of 2.0 mW, whlch allows us to perform multiple measurements of up to 10 machine axes simultaneously.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.920-924
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• 2003

This paper on measurement of curvature radius by the using of laser interferometer and prove. Mean value compared of ball and bearing It is developed program for date creation, and the verification using program. Measurement object center and curvature radius taking of LSC. when it is compared bearing prove with ball prove, the bearing prove can not proper by reason of big uncertainty and If laser setting error decrease, curvature radius get precision radius 10$\^$-5/.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.1195-1198
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• 2003

Micro former has been known as a useful tool for machining micro parts. It makes micro holes automatically with punches, a hole-shape die and material by rotation of crank shaft synchronously. Micro displacement in micro forming affects on the performance of machining because micro forming size is similar with its mechanical displacement. Therefore, the measurement of this micro displacement is essential to be guaranteed to obtain high forming precision in the whole machine as well as its devices. This paper addresses the development of a laser interferometer to measure micro displacement for a micro former. The laser interferometer is able to measure micro displacement during a few micro seconds with non-contact. For the experiment, a laser probe is installed on the optical table with optical devices and a micro displacement generating device. The velocity decoding board is also added to calculate doppler shift frequency directly. Finally simple experiments are conducted to confirm its functional operation.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.929-933
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• 2003

Internal defects of thin pressure vessel used in the power plants or the chemical plants may be created and grow due to corrosion or creep fatigue to reduce the strength and cause critical failure during operation. Therefore it is very important to detect this defect at the early stage. For this purpose, non-destructive, non-contact and highly sensitive method should be considered for on-line application. In this paper, a laser shearographic interferometer is applied to inspect circular defects and notch defects existed inside of thin pressure vessel under the presence of pressure up to 3 times of atmospheric pressure. The influences of the defect shape and size as well as the internal pressure to the characteristic pattern in the shearography fringe are investigated, and the quantitative evaluation of the defect size is tried. Also the experimental results are compared with the destructive test results to show the applicability of this method to the quantitative evaluation of internal defects in the thin pressure vessel.

• 한국공작기계학회논문집
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• 제13권6호
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• pp.34-40
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• 2004

This paper presents studies on curvature radius measurement using the laser interferometer. It is a general practice to measure to $10^{-10}$m in length with the recent improvement and innovations in measurement technology and the processor used. The measurement methods can generally be categorized as these two: the contactual method and non-contactual method; and in this study, we will find ways to lower the cost for a CMM, or a coordinate measurement machine, and try to find an alternative. Furthermore, we will discuss some of the ways to improve the non-contactual measurement methods-optical interferometer method and the optical triangulation method. We will measure an object using a laser distance measuring device and Set the Point-contact result with the ball-bearing type and line-contact result with the bearing type, to decide on which probe type will be used.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 심포지엄 논문집 정보 및 제어부문
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• pp.342-344
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• 2006

During last years, large investments have been directed to development and research of nano-technological products like semiconductor, display panel, optic-fiber communication components, life technology, and ultra-precision components. All quantitative measurements at nanometre scale should guarantees accurate results and high quality. Laser interferometer is one of most famous nanometre scale devices to be able to measure metre-scale distance with nanometre scale resolution, but it is easily affected by various error causes like geometrical, instrumental and environmental factor. On the other side, capacitive sensor is robust to above error factors, but it is able to measure relatively shorter distance, under $100{\mu}m$, than laser interferometer. New error correction method for laser interferometry using capacitive sensor will be introduced in this paper.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 추계학술대회 논문집
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• pp.922-925
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• 2005

This article describes a FM modulation algorithm to increase the measurement speed by increasing the beat frequency of the laser without acousto-optic modulator(AOM) in the heterodyne laser interferometer. The proposed algorithm can increase the beat frequency of the heterodyne laser which limit the measurement speed by adjusting a carrier frequency through electronic circuit, while AOM is used to shift the frequency of the heterodyne laser in conventional method. Electronic circuit is constructed to modulate the signals from a laser interferometer and a waveform generator. The brier analysis, the measurement scheme of the system, and the experimental results using a Zeeman-stabilized He-Ne laser are presented. They demonstrate that the proposed algorithm is proven to enhance the measurement speed limit by increasing the beat frequency of the heterodyne laser.