• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.06a
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• pp.693-694
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• 2008

• Korean Journal of Optics and Photonics
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• v.10 no.4
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• pp.283-288
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• 1999

We investigated the characteristics of surface roughness evaluation using phase-measuring interferometer for a few ten $\AA$ and sub $\AA$-rough substrates. The influence of phase averaging and intensity averaging on the roughness measurement by phase measuring interferometer was investigated and the optimal number of phase and intensity averaging for the least measurement error was searched. For a few ten $\AA$-rough sample, roughness value did not depend so much on the data averaging. Whereas, measurement error for sub $\AA$-rough sample was significantly improved as the number of phase and intensity averaging increased. At the phase averaging of 30 and the intensity averaging of 20, roughness value that measurement error was minimized was obtained, and it was in good agreement with that by optical heterodyne interferometer. Roughness measurement at the optimal data averaging showed also good repeatability error less than 0.01$\AA$.

• Journal of the Optical Society of Korea
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• v.10 no.1
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• pp.48-54
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• 2006

White-light scanning interferometry (WLI) and phase shifting interferometry (PSI) are increasingly used for surface topography measurements, particularly for areal measurements. In this paper, we compare surface profiling results obtained from above two optical methods with those obtained from stylus instruments. For moderately rough surfaces ($Ra{\approx}500\;nm$), roughness measurements obtained with WLI and the stylus method seem to provide close agreement on the same roughness samples. For surface roughness measurements in the 50 nm to 300 nm range of Ra, discrepancies between WLI and the stylus method are observed. In some cases the discrepancy is as large as 109% of the value obtained with the stylus method. By contrast, the PSI results are in good agreement with those of the stylus technique.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1997.10a
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• pp.254-259
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• 1997

The measurement of surface roughness and waviness by means of noncontact method is an important area to be developed for GAC(Geometrical Adaptive Control) system. This paper deal with the design of noncontact in-process measurement system which measures the surface roughness and waviness during cylindrical grinding. This measuring system is simple and the apparatus proposed is composed of a laser unit, photodetector and optical system. During operation, the surface of a workpiece is continuously scanned by a laser beam. This method makes it possible to detect the surface roughness and waviness along the feed direction by control the spot diameter of laser beam. The experimental results show that the presence of chattering, loading and glazing can be detected sensitively along the feed directions.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.47-48
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• 2006

A roughness measuring system which comprises an integrating sphere and a stabilized laser has been fabricated with the aim of measuring the roughness correction value which is necessary in gauge block measurement by optical interferometry. To calibrate the system, a Newton's ring interferometer has been introduced. The method how to calibrate the roughness measurement system has been described.

• Current Optics and Photonics
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• v.1 no.6
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• pp.604-612
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• 2017

An effective and precise method using a scanning white-light interferometer (SWLI) for three-dimensional surface measurements, in particular for roughness measurements, has been proposed. The measurement of a microscopically sloped area using an interferometer has limitations, due to the numerical aperture of the lens. In particular, for roughness measurements, it is challenging to obtain accurate height data for a sloped area using the interferometer, due to diffraction of the light. Owing to these optical limitations of the interferometer for roughness measurements, the Ra measurements performed using an interferometer contain errors. To overcome the limitations, we propose a method consisting of the following two steps. First, we evaluate the height data and set the invalid height area to be blank, using the characteristics of the modulus peak, which has a low peak value for signals that have low reliability in the interferogram. Next, we interpolate the blank area using the adjacent reliable area. Rubert roughness standards are used to verify the proposed method. The results obtained by the proposed method are compared to those obtained with a stylus profilometer. For the considered sinusoidal samples, Ra ranges from $0.053{\mu}m$ to $6.303{\mu}m$, and we show that the interpolation method is effective. In addition, the method can be applied to a random surface where Ra ranges from $0.011{\mu}m$ to $0.164{\mu}m$. We show that the roughness results obtained using the proposed method agree well with profilometer results. The $R^2$ values for both sinusoidal and random samples are greater than 0.995.

• Proceedings of the Optical Society of Korea Conference
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• 2006.02a
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• pp.209-210
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• 2006

• Journal of the Korean Society for Precision Engineering
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• v.21 no.4
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• pp.79-87
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• 2004

The light pattern reflected from a machined surface contains some information like roughness and profile on the projected surface as expected in the Beckmann-Spizzichino model. In applying the theory into a real reliable measuring device, many parameters such as incident light power, wave length, spot size should be kept a constant optical value. However, the reflected light power is likely to change with the environmental noise, the variations of the light source, the reflectivity of the surface, etc. even though the incident light power is constant. In this study, a method for adjusting the incident light power to keep the reflected light power projected on a CMOS image sensor constant was proposed and a simple adjustment algorithm based on PI digital control was examined. Experiments verified that the proposed method made the surface roughness measurement better and more reliable even under variations of the height of light source.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.26 no.3
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• pp.194-197
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• 2013

We investigated the effect of etching time on the surface roughness, and electrical and optical properties of ZnO and 2 wt% Al-doped ZnO (AZO) films. The ZnO and AZO films were deposited on glass substrates by RF magnetron sputtering technique. The etching experiment was carried out using a solution of 5% HCl at room temperature. The surface roughness was characterized by Atomic Force Microscopy. The electrical property was measured by Hall measurement system and 4-point probe. The optical property was characterized by UV-vis spectroscopy. After the wet chemical etching, the surface textures were obtained on the surface of the ZnO and AZO films. With the increase of etching time, the surface roughness (RMS) of the films increased and the transmittance of the films was observed to decrease. For the AZO film, a low resistivity of $1.0{\times}10^{-3}\;{\Omega}{\cdot}cm$ was achieved even after the etching.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.4
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• pp.1844-1849
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• 2014

Existing measurement methods using microscopes or surface roughness measurement instruments for surface control in manufacturing die are low in their efficiency when they are applied in industrial fields due to structural problems. Therefore, it is very important to develop a measurement and analysis system which can enhance efficiency in the measurement of different-sized manufacturing dies and provide quality control regardless of location. This study aimed at the development of a portable surface measurement system to satisfy this need. This measurement system was designed and manufactured in such a way as to divide it into three parts: the Base, the Body, and the Optical system. As a result of testing the system, the surface roughness was measured with an accuracy between 94.9 and 99.9%, and the deviation in the measurement value of a circle was within $2{\mu}m$.