The Experts below are selected from a list of 1965 Experts worldwide ranked by ideXlab platform
Kiyoshi Takamasu - One of the best experts on this subject based on the ideXlab platform.
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three dimensional Surface profile measurement of a cylindrical Surface using a multi beam angle sensor
Precision Engineering-journal of The International Societies for Precision Engineering and Nanotechnology, 2020Co-Authors: Meiyun Chen, Satoru Takahashi, Shengli Xie, Kiyoshi TakamasuAbstract:Abstract To investigate the application of the multi-beam angle sensor (MBAS) to high-precision optical Aspheric and freeform Surfaces, which are critical components in optical systems, we present a method of using an MBAS to reconstruct an Aspheric Surface from angle data. The MBAS is based on a multi-autocollimator system with a microlens array, which can split the beam into several spots and can convert centroid detection of the light intensity into an angle measurement. The MBAS is designed to address the curvature-range problem via a circumferential scan better than other methods and automatically eliminates the tilt error caused by rotation of a workpiece. Using a tracking technique, the MBAS can automatically determine focal spot positions from the centroid measurement of the light intensity. This is directly related to the accuracy of the angular difference measurement. The experimental results confirm the feasibility of using an MBAS for 3D Surface profile measurements of cylindrical Surfaces.
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Calibration for the sensitivity of multi-beam angle sensor using cylindrical plano-convex lens
Precision Engineering, 2016Co-Authors: Meiyun Chen, Satoru Takahashi, Kiyoshi TakamasuAbstract:Abstract A highly sensitive and compact multi-beam angle sensor (MBAS), which utilizes the principle of operation of an autocollimator, was developed to detect the differential of the local slope components (angle difference) of a point on the mirror Surface and using Fourier series, we can obtain the profile data from the angle difference. In order to investigate the application of the MBAS for high precision Aspheric Surface measurements, two types of calibration methods using plane mirror and cylindrical plano-convex lens has been proposed to measure the sensitivity of the MBAS. The calibration data analysis results using plane mirror agree well with the measurement results of the cylindrical plano-convex lens data. Comparison of the two methods confirms that the second method (using cylindrical plano-convex lens) is more adapted for measurement with ultra high level of uncertainty. Further, the second method is simple, corresponding to a direct calculate in the sensitive parameters aiming to minimize the cost.
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nanometer profile measurement of large Aspheric optical Surface by scanning deflectometry with rotatable devices uncertainty propagation analysis and experiments
Precision Engineering-journal of The International Societies for Precision Engineering and Nanotechnology, 2012Co-Authors: Muzheng Xiao, Satoru Takahashi, Satomi Jujo, Kiyoshi TakamasuAbstract:Abstract High-accuracy mirrors and lenses with large dimensions are widely used in huge telescopes and other industrial fields. Interferometers are widely used to measure near flat Surfaces and spherical optical Surfaces because of their high accuracy and high efficiency. Scanning deflectometry is also used for measuring optical near flat Surfaces with sub-nanometer uncertainty. However, for measuring an Aspheric Surface with a large departure from a perfect spherical Surface, both of these methods are difficult to use. The key problem for scanning deflectometry is that high-accuracy autocollimators usually have a limited measuring range less than 1000″, so it cannot be used for measuring Surfaces having a large slope. We have proposed a new method for measuring large Aspheric Surfaces with large slopes based on a scanning deflectometry method in which rotatable devices are used to enlarge the measuring range of the autocollimator. We also proposed a method to connect the angle data which is cut by the rotation of the rotatable devices. An analysis of uncertainty propagation in our proposed method was done. The result showed that when measuring a large Aspheric Surface with a diameter over 300 mm and a slope of 10 arc-deg, the uncertainty was less than 10 nm. For the verification of our proposed method, experimental devices were set up. A spherical optical mirror with a diameter of 35 mm and curvature radius of 5000 mm was measured. The measuring range of the autocollimator was successfully enlarged by our proposed method. Experimental results showed that the average standard deviation of 10 times measurement was about 20 nm.
Meiyun Chen - One of the best experts on this subject based on the ideXlab platform.
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three dimensional Surface profile measurement of a cylindrical Surface using a multi beam angle sensor
Precision Engineering-journal of The International Societies for Precision Engineering and Nanotechnology, 2020Co-Authors: Meiyun Chen, Satoru Takahashi, Shengli Xie, Kiyoshi TakamasuAbstract:Abstract To investigate the application of the multi-beam angle sensor (MBAS) to high-precision optical Aspheric and freeform Surfaces, which are critical components in optical systems, we present a method of using an MBAS to reconstruct an Aspheric Surface from angle data. The MBAS is based on a multi-autocollimator system with a microlens array, which can split the beam into several spots and can convert centroid detection of the light intensity into an angle measurement. The MBAS is designed to address the curvature-range problem via a circumferential scan better than other methods and automatically eliminates the tilt error caused by rotation of a workpiece. Using a tracking technique, the MBAS can automatically determine focal spot positions from the centroid measurement of the light intensity. This is directly related to the accuracy of the angular difference measurement. The experimental results confirm the feasibility of using an MBAS for 3D Surface profile measurements of cylindrical Surfaces.
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Calibration for the sensitivity of multi-beam angle sensor using cylindrical plano-convex lens
Precision Engineering, 2016Co-Authors: Meiyun Chen, Satoru Takahashi, Kiyoshi TakamasuAbstract:Abstract A highly sensitive and compact multi-beam angle sensor (MBAS), which utilizes the principle of operation of an autocollimator, was developed to detect the differential of the local slope components (angle difference) of a point on the mirror Surface and using Fourier series, we can obtain the profile data from the angle difference. In order to investigate the application of the MBAS for high precision Aspheric Surface measurements, two types of calibration methods using plane mirror and cylindrical plano-convex lens has been proposed to measure the sensitivity of the MBAS. The calibration data analysis results using plane mirror agree well with the measurement results of the cylindrical plano-convex lens data. Comparison of the two methods confirms that the second method (using cylindrical plano-convex lens) is more adapted for measurement with ultra high level of uncertainty. Further, the second method is simple, corresponding to a direct calculate in the sensitive parameters aiming to minimize the cost.
Yong Jian Zhu - One of the best experts on this subject based on the ideXlab platform.
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discussions on on machine measurement of Aspheric lens mold Surface
Optik, 2013Co-Authors: Yong Jian Zhu, Weiqing Pan, Yanan ZhiAbstract:Abstract At present, regarding to the machining of Aspheric lens mold, there are two major methods to carry out the on-machine measurement (OMM) — contacting method (CM) and non-contacting method (NCM). Here such two methods are reviewed in detail. CM is mainly based on the contacting probe which is scratching Aspheric Surface of lens mold to achieve profile data. To be efficient, an idea with 45° tilt of probe is proposed for OMM of lens mold by Suzuki. But generally speaking, the contacting OMM is not so efficient and can only deal with axisymmetric Aspheric lens mold. On the contrary, NCM mostly uses laser to achieve Aspheric profile without any contact. On ultra-precision lathe, laser scanning system or laser interferometer is mounted on the frame of lathe and transfers measurement data to machining system efficiently. However, most NCMs need stable environment and low working noise except instantaneous phase-shifting shearing interferometry (IPSSI). Therefore, a new idea about IPSSI is proposed in this paper to realize OMM of lens molds. Unfortunately, it's also difficult to test the high numerical aperture Aspheric or free-form lens molds. By comparison, the newly-developed fringe reflection (FR) method is becoming the promising method because it features the high efficiency and high accuracy. However, this method has not been used for OMM system yet. Much research should be conducted for FR OMM technology.
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profile error compensation in ultra precision grinding of Aspheric Surfaces with on machine measurement
International Journal of Machine Tools & Manufacture, 2010Co-Authors: Fengjun Chen, Shaohui Yin, Han Huang, Hitoshi Ohmori, Yong Qiang Wang, Yufeng Fan, Yong Jian ZhuAbstract:A compensation approach based on the on-machine measurement was developed for the grinding of tungsten carbide Aspheric moulds. In this approach, the on-machine measurement was employed to eliminate the profile error caused by the re-installation of the workpiece. A new method was proposed to reconstruct the actual ground profile based on the measured profile data. The overall profile error after grinding was obtained by subtracting the target profile from the actual ground profile along normal direction and was then used to generate a new tool path for compensation grinding. The experimental results showed that after three compensation grinding cycles the Aspheric Surface had a profile accuracy of 177 nm (in PV) with a roughness of 1.7 nm (in Ra). The on-machine measurement was in excellent agreement with the off-machine measurement by commercially available profilometers.
Qiang Chen - One of the best experts on this subject based on the ideXlab platform.
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experimental study on measurement of Aspheric Surface shape with complementary annular subaperture interferometric method
Optics Express, 2007Co-Authors: Xi Hou, Li Yang, Qiang ChenAbstract:Based on our previously reported annular subaperture reconstruction algorithm with Zernike annular polynomials and matrix method, we provide an experimental demonstration by testing a parabolic mirror with the complementary annular subaperture interferometric method. By comparing the results of annular subaperture method with that of the classical auto-collimation method, it is shown that the reconstruction results are in good agreement with the auto-collimation measurement. In addition, we discuss some limitations of characterizing annular subaperture measurement data with finite Zernike coefficients in our algorithm, and also show the possibility of characterizing higher spatial frequency information with adequate Zernike coefficients. It is believable that the reported method can be extended to test the Surface shape of some large concave Aspheric mirrors with acceptable accuracy.
Satoru Takahashi - One of the best experts on this subject based on the ideXlab platform.
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three dimensional Surface profile measurement of a cylindrical Surface using a multi beam angle sensor
Precision Engineering-journal of The International Societies for Precision Engineering and Nanotechnology, 2020Co-Authors: Meiyun Chen, Satoru Takahashi, Shengli Xie, Kiyoshi TakamasuAbstract:Abstract To investigate the application of the multi-beam angle sensor (MBAS) to high-precision optical Aspheric and freeform Surfaces, which are critical components in optical systems, we present a method of using an MBAS to reconstruct an Aspheric Surface from angle data. The MBAS is based on a multi-autocollimator system with a microlens array, which can split the beam into several spots and can convert centroid detection of the light intensity into an angle measurement. The MBAS is designed to address the curvature-range problem via a circumferential scan better than other methods and automatically eliminates the tilt error caused by rotation of a workpiece. Using a tracking technique, the MBAS can automatically determine focal spot positions from the centroid measurement of the light intensity. This is directly related to the accuracy of the angular difference measurement. The experimental results confirm the feasibility of using an MBAS for 3D Surface profile measurements of cylindrical Surfaces.
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Calibration for the sensitivity of multi-beam angle sensor using cylindrical plano-convex lens
Precision Engineering, 2016Co-Authors: Meiyun Chen, Satoru Takahashi, Kiyoshi TakamasuAbstract:Abstract A highly sensitive and compact multi-beam angle sensor (MBAS), which utilizes the principle of operation of an autocollimator, was developed to detect the differential of the local slope components (angle difference) of a point on the mirror Surface and using Fourier series, we can obtain the profile data from the angle difference. In order to investigate the application of the MBAS for high precision Aspheric Surface measurements, two types of calibration methods using plane mirror and cylindrical plano-convex lens has been proposed to measure the sensitivity of the MBAS. The calibration data analysis results using plane mirror agree well with the measurement results of the cylindrical plano-convex lens data. Comparison of the two methods confirms that the second method (using cylindrical plano-convex lens) is more adapted for measurement with ultra high level of uncertainty. Further, the second method is simple, corresponding to a direct calculate in the sensitive parameters aiming to minimize the cost.
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nanometer profile measurement of large Aspheric optical Surface by scanning deflectometry with rotatable devices uncertainty propagation analysis and experiments
Precision Engineering-journal of The International Societies for Precision Engineering and Nanotechnology, 2012Co-Authors: Muzheng Xiao, Satoru Takahashi, Satomi Jujo, Kiyoshi TakamasuAbstract:Abstract High-accuracy mirrors and lenses with large dimensions are widely used in huge telescopes and other industrial fields. Interferometers are widely used to measure near flat Surfaces and spherical optical Surfaces because of their high accuracy and high efficiency. Scanning deflectometry is also used for measuring optical near flat Surfaces with sub-nanometer uncertainty. However, for measuring an Aspheric Surface with a large departure from a perfect spherical Surface, both of these methods are difficult to use. The key problem for scanning deflectometry is that high-accuracy autocollimators usually have a limited measuring range less than 1000″, so it cannot be used for measuring Surfaces having a large slope. We have proposed a new method for measuring large Aspheric Surfaces with large slopes based on a scanning deflectometry method in which rotatable devices are used to enlarge the measuring range of the autocollimator. We also proposed a method to connect the angle data which is cut by the rotation of the rotatable devices. An analysis of uncertainty propagation in our proposed method was done. The result showed that when measuring a large Aspheric Surface with a diameter over 300 mm and a slope of 10 arc-deg, the uncertainty was less than 10 nm. For the verification of our proposed method, experimental devices were set up. A spherical optical mirror with a diameter of 35 mm and curvature radius of 5000 mm was measured. The measuring range of the autocollimator was successfully enlarged by our proposed method. Experimental results showed that the average standard deviation of 10 times measurement was about 20 nm.
