D. Nečas, I. Ohlídal, J. Vodák, M. Ohlídal, D. Franta
A new optical characterization method based on imaging spectroscopic reflectometry (ISR) is presented and illustrated on the characterization of rough non-uniform epitaxial ZnSe films prepared on GaAs substrates. The method allows the determination of all parameters describing the thin films exhibiting boundary roughness and non-uniformity in thickness, i.e. determination of the spectral dependencies of the optical constants, map of local thickness and map of local rms values of heights of the irregularities for the rough boundaries. The local normal reflectance spectra in ISR correspond to small areas (37×37 μm2) on the thin films measured within the spectral range 270{900 nm by pixels of a CCD camera serving as the detector of imaging spectrophotometer constructed in our laboratory. To our experience the small areas corresponding to the pixels are sufficiently small so that the majority of the films can be considered uniform in all parameters within these areas. Boundary roughness is included into the reflectance formulas by means of the scalar diffraction theory (SDT) and the optical constant spectra of the ZnSe films were expressed by the dispersion model based on the parametrization of the joint density of electronic states (PJDOS). In general, there is a correlation between the searched parameters if the individual local reflectance spectra are fitted separately and, therefore, the local reflectance spectra measured for all the pixels are treated simultaneously using so called multi-pixel method in order to remove or reduce this correlation and determine the values of all the parameters with a sufficient accuracy. The results of the optical characterization of the same selected sample of the epitaxial ZnSe thin film obtained using the method presented here and combined method of variable-angle spectroscopic ellipsometry, spectroscopic reflectometry and single-pixel immersion spectroscopic reflectometry are introduced in the contribution as well.
{"title":"Simultaneous determination of optical constants, local thickness, and local roughness of thin films by imaging spectroscopic reflectometry","authors":"D. Nečas, I. Ohlídal, J. Vodák, M. Ohlídal, D. Franta","doi":"10.1117/12.2190091","DOIUrl":"https://doi.org/10.1117/12.2190091","url":null,"abstract":"A new optical characterization method based on imaging spectroscopic reflectometry (ISR) is presented and illustrated on the characterization of rough non-uniform epitaxial ZnSe films prepared on GaAs substrates. The method allows the determination of all parameters describing the thin films exhibiting boundary roughness and non-uniformity in thickness, i.e. determination of the spectral dependencies of the optical constants, map of local thickness and map of local rms values of heights of the irregularities for the rough boundaries. The local normal reflectance spectra in ISR correspond to small areas (37×37 μm2) on the thin films measured within the spectral range 270{900 nm by pixels of a CCD camera serving as the detector of imaging spectrophotometer constructed in our laboratory. To our experience the small areas corresponding to the pixels are sufficiently small so that the majority of the films can be considered uniform in all parameters within these areas. Boundary roughness is included into the reflectance formulas by means of the scalar diffraction theory (SDT) and the optical constant spectra of the ZnSe films were expressed by the dispersion model based on the parametrization of the joint density of electronic states (PJDOS). In general, there is a correlation between the searched parameters if the individual local reflectance spectra are fitted separately and, therefore, the local reflectance spectra measured for all the pixels are treated simultaneously using so called multi-pixel method in order to remove or reduce this correlation and determine the values of all the parameters with a sufficient accuracy. The results of the optical characterization of the same selected sample of the epitaxial ZnSe thin film obtained using the method presented here and combined method of variable-angle spectroscopic ellipsometry, spectroscopic reflectometry and single-pixel immersion spectroscopic reflectometry are introduced in the contribution as well.","PeriodicalId":212434,"journal":{"name":"SPIE Optical Systems Design","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116959039","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Adinda-Ougba, B. Kabir, N. Koukourakis, F. Mitschker, N. Gerhardt, M. Hofmann
Digital holography is capable of providing surface profiles of samples with axial resolution in the nanometer range. Lensless digital holography is a well-established microscopic method providing diffraction limited resolution of the order of the wavelength of the used light source. It is based on inline holography and usually allows imaging only in transmission geometry. In this contribution we propose a compact low cost lensless digital holographic microscope capable of performing measurements on reflective microstructures. The novelty of the system consists on a direct use of a laser diode without any need of coupling optics as light source. This simplifies the setup and provides sufficient magnification to measure microstructures. We evaluate our setup by imaging reflective microstructures. We have achieved ̴ 6 mm2 field of view amplitude images with ̴ 2.5μm lateral resolution and phase images with axial resolution in nanometer range. The phase image provides a full-field profile measurement of the sample in nanometer range.
{"title":"Compact low-cost lensless digital holographic microscope for topographic measurements of microstructures in reflection geometry","authors":"A. Adinda-Ougba, B. Kabir, N. Koukourakis, F. Mitschker, N. Gerhardt, M. Hofmann","doi":"10.1117/12.2191073","DOIUrl":"https://doi.org/10.1117/12.2191073","url":null,"abstract":"Digital holography is capable of providing surface profiles of samples with axial resolution in the nanometer range. Lensless digital holography is a well-established microscopic method providing diffraction limited resolution of the order of the wavelength of the used light source. It is based on inline holography and usually allows imaging only in transmission geometry. In this contribution we propose a compact low cost lensless digital holographic microscope capable of performing measurements on reflective microstructures. The novelty of the system consists on a direct use of a laser diode without any need of coupling optics as light source. This simplifies the setup and provides sufficient magnification to measure microstructures. We evaluate our setup by imaging reflective microstructures. We have achieved ̴ 6 mm2 field of view amplitude images with ̴ 2.5μm lateral resolution and phase images with axial resolution in nanometer range. The phase image provides a full-field profile measurement of the sample in nanometer range.","PeriodicalId":212434,"journal":{"name":"SPIE Optical Systems Design","volume":"2002 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127329059","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Muñoz Potosi, L. G. Valdivieso-González, R. Díaz-Uribe, M. Campos García, F. G. Granados Agustín
There are a variety of techniques to determine the quality of optical surfaces, which provide quantitative information of the deformation of the shape of the surface under test. This work proposes to use the deflectometry technique using a Hartmann screen to test a spherical surface with a local deformation. In order to perform the theoretical analysis, a model of experimental setup in which the input parameters: the position of the Hartmann type screen and the location for each of its holes, the distance of the observation plane and the positions of the reflected rays, are known. With this model, based on the diameter of the deformation and deviation of the incident and reflected rays in the observation plane, we determine the theoretical sensitivity of the technique proposed.
{"title":"Sensitivity of null testing for a local deformation","authors":"A. Muñoz Potosi, L. G. Valdivieso-González, R. Díaz-Uribe, M. Campos García, F. G. Granados Agustín","doi":"10.1117/12.2191545","DOIUrl":"https://doi.org/10.1117/12.2191545","url":null,"abstract":"There are a variety of techniques to determine the quality of optical surfaces, which provide quantitative information of the deformation of the shape of the surface under test. This work proposes to use the deflectometry technique using a Hartmann screen to test a spherical surface with a local deformation. In order to perform the theoretical analysis, a model of experimental setup in which the input parameters: the position of the Hartmann type screen and the location for each of its holes, the distance of the observation plane and the positions of the reflected rays, are known. With this model, based on the diameter of the deformation and deviation of the incident and reflected rays in the observation plane, we determine the theoretical sensitivity of the technique proposed.","PeriodicalId":212434,"journal":{"name":"SPIE Optical Systems Design","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126020171","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Optical surface quality plays a significant role when considering laser applications. Specifically, short pulses, high pulse energies and shorter wavelength impose high requirements on surface characteristics. Amongst others, scatter losses, absorption, or the damage threshold place high demands on the specification of an optical part, and each application will define the order in priority of these properties. We have conducted several experiments to investigate in the impact of surface characteristics of polished substrates on the performance of coated optics. In this contribution we report on the techniques used to qualify dielectric coatings for excellent power handling capabilities based on the substrate surface finish.
{"title":"Optical surfaces for high power laser coatings","authors":"L. Jensen, D. Ristau","doi":"10.1117/12.2190931","DOIUrl":"https://doi.org/10.1117/12.2190931","url":null,"abstract":"Optical surface quality plays a significant role when considering laser applications. Specifically, short pulses, high pulse energies and shorter wavelength impose high requirements on surface characteristics. Amongst others, scatter losses, absorption, or the damage threshold place high demands on the specification of an optical part, and each application will define the order in priority of these properties. We have conducted several experiments to investigate in the impact of surface characteristics of polished substrates on the performance of coated optics. In this contribution we report on the techniques used to qualify dielectric coatings for excellent power handling capabilities based on the substrate surface finish.","PeriodicalId":212434,"journal":{"name":"SPIE Optical Systems Design","volume":"80 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121682130","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Zhixiang Liu, Tingwen Xin, Yadong Jiang, B. Lv, Fuchao Xu
Lateral shearing interferometry is an attractive technique to measure the wavefront aberration of high numerical aperture optical systems, of which using two-dimensional grating can divide and shear the wavefront in two-dimension simultaneously. A two-dimension lateral shearing interferometer based on chessboard grating was designed, which can work in dual-mode: the phase shifting mode and the Fourier transform mode. In the phase shifting mode, the phase shifting was realized by moving chessboard grating along the shearing direction in the image plane. In the Fourier transform mode, the spatial carrier frequency was realized by positioning the grating at the Talbot distance of the objective image plane. An experimental setup was designed to measure a 10×, NA0.25 microscope objective at 632.8nm wavelength. The objective was measured by the experimental setup in dual-mode, the results showed that the wavefront of the objective was 0.172λ RMS; in the phase shifting mode, the repeatability (3σ) of RMS was 1.1mλ; in the Fourier transform mode, the repeatability (3σ) of RMS was 2.7mλ; after correcting the coordinates of the wavefront, the differences of Z5 to Z36 between phase shifting mode and the Fourier transform mode were better than 8mλ.
横向剪切干涉法是测量高数值孔径光学系统波前像差的一种有吸引力的技术，利用二维光栅可以同时对波前进行二维分割和剪切。设计了一种基于棋盘光栅的二维横向剪切干涉仪，该干涉仪可以工作在相移模式和傅里叶变换模式下。在移相模式下，通过在像平面上沿剪切方向移动棋盘光栅来实现移相。在傅里叶变换模式下，将光栅定位在物象平面的塔尔博特距离上实现空间载波频率。设计了一种测量632.8nm波长下10倍NA0.25显微镜物镜的实验装置。利用双模实验装置对物镜进行测量，结果表明，物镜的波前RMS为0.172λ;在相移模式下，RMS的重复性(3σ)为1.1 mm λ;在傅里叶变换模式下，RMS的重复性(3σ)为2.7mλ;对波前坐标进行校正后，相移模式与傅里叶变换模式Z5 ~ Z36的差值大于8mm。
{"title":"Two-dimension lateral shearing interferometry with dual-mode","authors":"Zhixiang Liu, Tingwen Xin, Yadong Jiang, B. Lv, Fuchao Xu","doi":"10.1117/12.2189878","DOIUrl":"https://doi.org/10.1117/12.2189878","url":null,"abstract":"Lateral shearing interferometry is an attractive technique to measure the wavefront aberration of high numerical aperture optical systems, of which using two-dimensional grating can divide and shear the wavefront in two-dimension simultaneously. A two-dimension lateral shearing interferometer based on chessboard grating was designed, which can work in dual-mode: the phase shifting mode and the Fourier transform mode. In the phase shifting mode, the phase shifting was realized by moving chessboard grating along the shearing direction in the image plane. In the Fourier transform mode, the spatial carrier frequency was realized by positioning the grating at the Talbot distance of the objective image plane. An experimental setup was designed to measure a 10×, NA0.25 microscope objective at 632.8nm wavelength. The objective was measured by the experimental setup in dual-mode, the results showed that the wavefront of the objective was 0.172λ RMS; in the phase shifting mode, the repeatability (3σ) of RMS was 1.1mλ; in the Fourier transform mode, the repeatability (3σ) of RMS was 2.7mλ; after correcting the coordinates of the wavefront, the differences of Z5 to Z36 between phase shifting mode and the Fourier transform mode were better than 8mλ.","PeriodicalId":212434,"journal":{"name":"SPIE Optical Systems Design","volume":"44 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116500127","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Kreuzer, Jordi Gomis Bresco, M. Sledzinska, C. S. Sotomayor Torres
The analysis of diffracted light from periodic structures is shown to be a versatile metrology technique applicable to inline metrology for periodic nanostructures. We show that 10 nm changes in periodic structures can be traced optically by means of sub-wavelength diffraction. Polymer gratings were fabricated by electron beam lithography. The gratings have a common periodicity of 6 μm, but different line width, ranging from 370 to 550 nm in 10 nm steps. A comparison between the resulting diffraction patterns shows marked differences in intensity which are used to sense nanometre scale deviations in periodic structures.
{"title":"In-line metrology setup for periodic nanostructures based on sub-wavelength diffraction","authors":"M. Kreuzer, Jordi Gomis Bresco, M. Sledzinska, C. S. Sotomayor Torres","doi":"10.1117/12.2191346","DOIUrl":"https://doi.org/10.1117/12.2191346","url":null,"abstract":"The analysis of diffracted light from periodic structures is shown to be a versatile metrology technique applicable to inline metrology for periodic nanostructures. We show that 10 nm changes in periodic structures can be traced optically by means of sub-wavelength diffraction. Polymer gratings were fabricated by electron beam lithography. The gratings have a common periodicity of 6 μm, but different line width, ranging from 370 to 550 nm in 10 nm steps. A comparison between the resulting diffraction patterns shows marked differences in intensity which are used to sense nanometre scale deviations in periodic structures.","PeriodicalId":212434,"journal":{"name":"SPIE Optical Systems Design","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129832805","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Most of the commercial available sub-aperture stitching interferometers measure the surface with a standard lens that produces a reference wavefront, and the precision of the interferometer is generally limited by the standard lens. The test accuracy can be achieved by removing the error of reference surface by the absolute testing method. When the testing accuracy (repeatability and reproducibility) is close to 1nm, in addition to the reference surface, other factors will also affect the measuring accuracy such as environment, zoom magnification, stitching precision, tooling and fixture, the characteristics of optical materials and so on. We establish a stitching system in the thousand level cleanroom. The stitching system is including the Zygo interferometer, the motion system with Bilz active isolation system at level VC-F. We review the traditional absolute flat testing methods and emphasize the method of rotation-shift functions. According to the rotation-shift method we get the profile of the reference lens and the testing lens. The problem of the rotation-shift method is the tilt error. In the motion system, we control the tilt error no more than 4 second to reduce the error. In order to obtain higher testing accuracy, we analyze the influence surface shape measurement accuracy by recording the environment error with the fluke testing equipment.
{"title":"Absolute testing of flats in sub-stitching interferometer by rotation-shift method","authors":"Xin Jia, Fuchao Xu, Weimin Xie, Yun Li, Ting-wen Xing","doi":"10.1117/12.2191288","DOIUrl":"https://doi.org/10.1117/12.2191288","url":null,"abstract":"Most of the commercial available sub-aperture stitching interferometers measure the surface with a standard lens that produces a reference wavefront, and the precision of the interferometer is generally limited by the standard lens. The test accuracy can be achieved by removing the error of reference surface by the absolute testing method. When the testing accuracy (repeatability and reproducibility) is close to 1nm, in addition to the reference surface, other factors will also affect the measuring accuracy such as environment, zoom magnification, stitching precision, tooling and fixture, the characteristics of optical materials and so on. We establish a stitching system in the thousand level cleanroom. The stitching system is including the Zygo interferometer, the motion system with Bilz active isolation system at level VC-F. We review the traditional absolute flat testing methods and emphasize the method of rotation-shift functions. According to the rotation-shift method we get the profile of the reference lens and the testing lens. The problem of the rotation-shift method is the tilt error. In the motion system, we control the tilt error no more than 4 second to reduce the error. In order to obtain higher testing accuracy, we analyze the influence surface shape measurement accuracy by recording the environment error with the fluke testing equipment.","PeriodicalId":212434,"journal":{"name":"SPIE Optical Systems Design","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132215035","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
P. Nádaský, J. Klus, J. Vodák, Štěpán Šustek, M. Ohlídal
Scattermeter II is the second generation device designed and built at The Institute of Physical Engineering, Faculty of Mechanical Engineering, Brno University of Technology. This device has been designed for measuring the angular distribution of the intensity of electromagnetic radiation scattered from a surface of a solid. In this paper, the basic scheme of Scattermeter II and measuring principles with it are described. The results achieved in electromagnetic radiation scattering from surfaces of selected samples of single crystalline silicon wafers used in solar cells are also presented.
{"title":"Scattermeter for measurement of solar cells","authors":"P. Nádaský, J. Klus, J. Vodák, Štěpán Šustek, M. Ohlídal","doi":"10.1117/12.2190779","DOIUrl":"https://doi.org/10.1117/12.2190779","url":null,"abstract":"Scattermeter II is the second generation device designed and built at The Institute of Physical Engineering, Faculty of Mechanical Engineering, Brno University of Technology. This device has been designed for measuring the angular distribution of the intensity of electromagnetic radiation scattered from a surface of a solid. In this paper, the basic scheme of Scattermeter II and measuring principles with it are described. The results achieved in electromagnetic radiation scattering from surfaces of selected samples of single crystalline silicon wafers used in solar cells are also presented.","PeriodicalId":212434,"journal":{"name":"SPIE Optical Systems Design","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115269065","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Three-dimensional image acquisition is still a growing field in optical metrology. Various methods are available to reconstruct an object’s three-dimensional surface. The five main types of 3D cameras are stereo cameras, triangulation (pattern or laser scanning), interferometry, light-field cameras and ToF (time-of-flight) cameras. PMD (photonic mixing device) cameras measure the time of light, and thus belong to the field of ToF cameras. Each camera type has fields of application for which it is particularly well suited. Even within PMD cameras, there is a distinction made between applications for indoor and outdoor use. Until today, there is no method to measure and characterize 3D cameras uniformly. Desirable would be a method, which is able to measure all types of cameras equally. With this work, we want to contribute to the standardization of 3D cameras. In this case, we use a PMD camera for outdoor applications with relatively large pixels. It is shown how to determine the spatial resolution of a PMD camera from both, the amplitude and the distance image. Further, a novel method is presented how to determine the resolution enhancement in an image via gradient image evaluation. Finally, a method is proposed which evaluates the quality of resolution enhancement, when no ground truth data is available. Both are particularly interesting for the use of super-resolution (SR) applications.
{"title":"Contribution to the standardization of 3D measurements using a high-resolution PMD camera","authors":"Henrik Lietz, Jörg Eberhardt","doi":"10.1117/12.2191042","DOIUrl":"https://doi.org/10.1117/12.2191042","url":null,"abstract":"Three-dimensional image acquisition is still a growing field in optical metrology. Various methods are available to reconstruct an object’s three-dimensional surface. The five main types of 3D cameras are stereo cameras, triangulation (pattern or laser scanning), interferometry, light-field cameras and ToF (time-of-flight) cameras. PMD (photonic mixing device) cameras measure the time of light, and thus belong to the field of ToF cameras. Each camera type has fields of application for which it is particularly well suited. Even within PMD cameras, there is a distinction made between applications for indoor and outdoor use. Until today, there is no method to measure and characterize 3D cameras uniformly. Desirable would be a method, which is able to measure all types of cameras equally. With this work, we want to contribute to the standardization of 3D cameras. In this case, we use a PMD camera for outdoor applications with relatively large pixels. It is shown how to determine the spatial resolution of a PMD camera from both, the amplitude and the distance image. Further, a novel method is presented how to determine the resolution enhancement in an image via gradient image evaluation. Finally, a method is proposed which evaluates the quality of resolution enhancement, when no ground truth data is available. Both are particularly interesting for the use of super-resolution (SR) applications.","PeriodicalId":212434,"journal":{"name":"SPIE Optical Systems Design","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132189862","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This method of optical scanning presented in this paper is used for precision measurement deformation in shape or absolute forms in comparison with a reference component form, of optical or mechanical components, on reduced surfaces area that are of the order of some mm2 and more. The principle of the method is to project the image of the source grating to palpate optically surface to be inspected, after reflection; the image of the source grating is printed by the object topography and is then projected onto the plane of reference grating for generate moiré fringe for defects detection. The optical device used allows a significant dimensional surface magnification of up to 1000 times the area inspected for micro-surfaces, which allows easy processing and reaches an exceptional nanometric imprecision of measurements. According to the measurement principle, the sensitivity for displacement measurement using moiré technique depends on the frequency grating, for increase the detection resolution. This measurement technique can be used advantageously to measure the deformations generated by the production process or constraints on functional parts and the influence of these variations on the function. The optical device and optical principle, on which it is based, can be used for automated inspection of industrially produced goods. It can also be used for dimensional control when, for example, to quantify the error as to whether a piece is good or rubbish. It then suffices to compare a figure of moiré fringes with another previously recorded from a piece considered standard; which saves time, money and accuracy. The technique has found various applications in diverse fields, from biomedical to industrial and scientific applications.
{"title":"Precision optical device of freeform defects inspection","authors":"S. Meguellati","doi":"10.1117/12.2191202","DOIUrl":"https://doi.org/10.1117/12.2191202","url":null,"abstract":"This method of optical scanning presented in this paper is used for precision measurement deformation in shape or absolute forms in comparison with a reference component form, of optical or mechanical components, on reduced surfaces area that are of the order of some mm2 and more. The principle of the method is to project the image of the source grating to palpate optically surface to be inspected, after reflection; the image of the source grating is printed by the object topography and is then projected onto the plane of reference grating for generate moiré fringe for defects detection. The optical device used allows a significant dimensional surface magnification of up to 1000 times the area inspected for micro-surfaces, which allows easy processing and reaches an exceptional nanometric imprecision of measurements. According to the measurement principle, the sensitivity for displacement measurement using moiré technique depends on the frequency grating, for increase the detection resolution. This measurement technique can be used advantageously to measure the deformations generated by the production process or constraints on functional parts and the influence of these variations on the function. The optical device and optical principle, on which it is based, can be used for automated inspection of industrially produced goods. It can also be used for dimensional control when, for example, to quantify the error as to whether a piece is good or rubbish. It then suffices to compare a figure of moiré fringes with another previously recorded from a piece considered standard; which saves time, money and accuracy. The technique has found various applications in diverse fields, from biomedical to industrial and scientific applications.","PeriodicalId":212434,"journal":{"name":"SPIE Optical Systems Design","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114784657","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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