[in Japanese]

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The fringe phase can be detected from one shot image in the shape measurement using color fringe projection. However in practice, it is difficult to analyze the phase precisely because the characteristics of spectrum are depend on the optical devices and the test object. The improvement of the measurement accuracy is attempted by the correction for detected hue information in this experiment. The hue distribution of the object is modified by using the reference hue of a flat surface. The accuracy is improved remarkably. Moreover, the ununiformity of the measurement sensitivity caused by the optical arrangement is corrected by calculations of geometrical relationship.

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To overcome the phase ambiguity problem in phase-shifting interferometry, multi-wavelength interferometry has been long investigated. However, its industrial application has been limited because of its complex optical configurations. This paper introduces a surface profiler which uses a low-cost and simple three-wavelength imaging system consisting of a white-light illuminator, a multi-bandpass filter and a color CCD camera. The algorithms used and experimental results are presented.

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The authors previously reported the development of an automatic film thickness measurement system based on three-wavelength single-shot interferometry. This paper introduces a development of a real-time surface measurement system. In order to reduce the computation time, GPU (Graphics Processing Unit) is introduced for parallel processing.

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[in Japanese]

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[in Japanese]

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[in Japanese]

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[in Japanese]

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In order to accurately measure profile on machine, it is necessary to remove influences of various disturbances such as vibration. Vibration between a workpiece and a sensor causes measurement error on machine measurement. So, the authors proposed the triangulation method sensor with optical skid to remove the vibration error and have showed effectiveness of vibration rejection. When the skid probe diameter is not very larger than wavelengths of the profile, the amplitude of measured profile is smaller than real amplitude. This paper presents reconstructing method of profile on optical skid sensor and effects obtained by simulation of using the reconstructing method.

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[in Japanese]

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To measure the Free Spectral Range (FSR) of a Fabry-Perot cavity, the absolute optical path length between two mirrors which compose a resonator can be measured. In the previous reports, we improved the measurement uncertainty of the FSR by increasing the modulation depth and increasing the laser intensity. In this report, to improve the measurement uncertainty of the FSR, we use a tapered amplifier to increase the intensity of modulated laser beam and modulate the laser beam at an integer multiple of the FSR.

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In this research, we develop a technique for high-resolution(10µm) and non-contact distance measurement for measuring objects. We use two optical frequency comb lasers as light sources, thus we make use of the stability of the repetition frequency of optical frequency comb for high-accuracy measurement. Moreover, we don′t have to consider cyclic error caused by RF frequency oscillator. This first report shows an experiment to demonstrate the measurement principle using two optical frequency comb lasers.

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[in Japanese]

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A heterodyne interference system is developed for position measurement. A stabilized optical-frequency comb is used as the laser source and the temporal coherence interference happens at discrete positions, where a pair of optical comb pulse trains overlaps with each other. An acoustic optical modulator generates a shifted frequency approximating the repetition rate of the optical comb so the frequency of heterodyne signal is the difference between the shifted frequency and the repetition rate. A piezo-electric transducer scans to find the position where the peak of interference fringe is to realize the absolute length measurement. The preliminary experiment has been done to measure the distance of 7.5 m. The measurement result shows a drift in one hour is 4.929 µm though the refractive index of air is not corrected. The experiments for longer distances while recording the environment condition are under planning.

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A high-frequency part of repetition frequency modes of a ultra-short pulsed, mode-locked fiber laser, is selected by a Fabry-Pérot etalon. The 3-GHz repetition-modified laser is transmitted to a Michelson interferometer. The interference fringes generated have a temporal coherence pattern at each 5 cm and can make positioning in space. The optical system of the interferometer is designed as double-path beam. A center between two beams is located at the position of a measuring probe of CMM. Using this design, we can apply the mode-locked fiber laser to artifacts following contact method. The advantage of the contact method can measure variety-shape artifacts, i.e. step gauge etc, that non-contact method cannot be used.

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[in Japanese]

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On-the-machine measurement is widely used for the quality control and the improvement of the productive efficiency. However, 3-D touch probes for the on-the-machine measurement still have some problems. An electrical short between a touch probe and a work caused by magnetized waste metals is one of the problems in case of conduction type probes. And it is one of the problems that few high aspect ratio probes have been provided in commercial use. In the region of micro-meso dimensional measuring, high-accuracy measuring method utilizing vibration proves had been invented. On the other hand, in this study, a macro dimensional vibration type 3-D touch probe has been investigated in accordance with the above problems. In this report, as a first step, a prototype 3-D touch probe, which has normal aspect ratio, has been developed and the repeatability of touch detection and contact force has been measured. The repeatability (2sigma) of x-axis, y-axis and z-axis measures +-0.62micrometer, +-0.60 micrometer, +-0.30 micrometer, respectively and the contact force of x-axis, y-axis and z-axis measures approximately 20mN, 12mN and 4mN, respectively.

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Coordinate measuring machines (CMMs) performance were inspected based on JIS B 7440-2:2003 by the means Geometrical product specifications (GPS), Acceptance and reverification tests for CMM, Part 2: CMMs used for measuring size, however it was feared to disturb comparison with CMMs performance that uncertainties composed different factors and values by different materials of artifact so had different properties. Here, round robin test on evaluation of performance of CMM were experimented using artifacts made of two different materials between Low CTE type and carbon steel type by Tohoku 6 prefectures public research institute as joint experiment. As a results, It were compared and verified that uncertainties of coordinate measurement obtained using different materials of Artifact.

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In recent years, the CMM (Coordinate Measuring Machine) quickly has been spreading in the manufacturing industry. With this phenomenon, the environmental condition and installation site of CMMs has been changed from the temperature control room to the workshop environment and the production line without air conditioning. However, even in severe environment the demand to high accuracy measurements by CMM has been enhancing still more. Therefore, the methods to evaluate and realize the high accuracy measurements by CMM in workshop environment have been investigated. In this paper, we clarify the factor of scale error and propose the effect and correction method of temperature measurement errors using scale error of C-MBG (Gauge Block with Coefficient of Thermal Expansion Data).

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Coordinate Measuring Machines (CMMs) are widely used in industry as a universal measuring instrument. The validation of reliability of CMM is important for quality assurance. The reverification test or interim check of CMM is, however, not often carried out by general CMM users. The reasons are the cost of the gauges for the test or check and the measuring skills. Therefore a simple inspection tool is expected. In this report, we describe the evaluation results of a simple inspection tool (Renishaw: Machine Checking Gauge) used for a CMM interim check.

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To develop a high precision Coordinate Measuring Machine called M-CMM, it is important to evaluate stage's kinematic error. In this research, we propose multi-probe method for M-CMM calibration which can separate reference mirror form and kinematic error of stage. In the last paper, we described systematic error caused by yawing error. In this paper, we reduce systematic error with compensating non linear terms consisted of yawing error and alignment error.

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[in Japanese]

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The goal of our research is to measure the profile of huge aspheric surface with accuracy of about 10 nm. Nowadays mirrors and lenses with high accuracy (around 100nm) with large dimension (more than 300 mm in diameter) are widely used in the telescopes and other industries. Usage of mirrors and lenses with high accuracy calls for technology to measure them in high accuracy of about 10 nm. In earlier report, we proposed a new method of measuring the surfaces based on scanning deflectometry technology. In this report, systematic errors are analyzed to endeavor to achieve higher accuracy. We investigated temperature and optical path length as systematic error factors, identifying a long optical path length as a systematic error factor. In addition, we conducted experiment to measure spherical surface with curvature radius of 1000 mm.

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[in Japanese]

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Spheres are widely used in industry as calibration standard, mechanical guide, optical parts, and so on. Commonly their geometrical parameters are evaluated as roundness by stylus contour measurement but a full spherical form is difficult to measure. Therefore, we have developed a system to measure the full spherical form by means of interferometry. The system consists of spherical Fizeau interferometer, mechanical stages to rotate and to orient a sphere, and software to generate full sphere form with stitching technique. We have found good agreement between the interferometric measurement of this system and a stylus contour measurement.

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[in Japanese]

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In this paper, we describe a concurrent measurement method for spindle radial, axial and angular motions using concentric circle grating interferometers. Three optical sensors, which consist of two interferometers, are fixed over the grating. One interferometer detects an interference signal between reflection lights from a fixed mirror and the grating for vertical displacement measurement. The other interferometer detects an interference signal between ±first order diffraction lights from the grating for lateral displacement measurement. From these measured displacements using three optical sensors, radial, axial and angular motions of the grating, i.e. the spindle, can be calculated concurrently.

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[in Japanese]

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This paper presents a spindle error measurement system to evaluate the performance of a spindle of a large-scale ultra-precision lathe, which is under development for fabrication of large roll dies with micro-structured surfaces. Measurement of the spindle error motion is an important issue for the ultra-precision lathe because the fabrication accuracy is influenced by the motion error. In order to measure the spindle error motion of the large-scale ultra-precision lathe, reversal technique is employed. In this research, large-scale roll workpiece is used as the measurement artifact instead of other master ball or cylinders. This paper reports the spindle error motion measurement with refined reversal operation method for the reversal of the large-scale roll workpiece. Spindle error motion was evaluated over the entire fabrication length (1.7 m) of the large-scale ultra-precision lathe.

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[in Japanese]

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Our passive THz near-field microscope probes spontaneous evanescent waves with 60 nm resolution without external illumination. Here we studied metal surfaces like Au and Al and we obtained more than 100 times stronger near-field signals as expected with the Planck′s formula. With theoretical and experimental analyses, we conclude that the signals should result from very strong electromagnetic local density of states generated by thermal charge/current fluctuations.

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[in Japanese]

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In order to develop an in-line monitoring system to measure the oil content in water-soluble coolant, a reflectance-type photo-electric sensor was introduced as an oil content meter. Keeping the oil content a normal level can extend the service life of water-soluble coolant. We compared the measured values change between the reflectance and Brix% (refraction) against to the oil content. A reflection-type photoelectric sensor can measure the oil content efficiently. The reflectance varied in proportion to the oil content as well as the case of Brix%. The reflectance change against to the oil content was not influenced by the circulation of coolant and bubble formation. Applying the photoelectric sensor makes in-process measurement of oil content in the in-service coolant.

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ISO 10360-7 which specifies acceptance and reverification tests for Vision Measuring Machines were published in May 2011. We intend accurately to calibrate the form deviation of circle patterns on photomask complying with the standard. For the purpose of establishing highly accurate calibration method, we construct the equipment which consists of a Vision Measuring Machine and a rotation stage, and we calibrate the form deviation with multistep method. Uncertainty factors of the calibration are investigated and appropriate calibration conditions are determined. As the result, we calibrated the form deviation and estimated the uncertainty to be 23 nm (k=2).

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[in Japanese]

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[in Japanese]

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