A new moiré interferometer for measuring in-plane displacement

Lin, Shiang‐Tai

doi:10.1007/bf02323189

Cited by 3 publications

(4 citation statements)

References 10 publications

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“…From equation (5), it is clear that the displacement is proportional to the grating pitch d and inversely proportional to the diffraction order l. The system resolution can be increased by utilizing a fine-pitch grating or high-order diffraction beams. In many previous works, ±1st order diffraction beams were used to form the fringe pattern, and the corresponding fringe multiplication was 2 [8,9]. But it was increased to 20 by using ±10th order diffraction beams in [10].…”

Section: System Optical Configurationmentioning

confidence: 99%

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Research on long-range grating interferometry with nanometer resolution

Chu

Lu²,

Zhao

2007

Meas. Sci. Technol.

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Grating interferometry that features long range and nanometer resolution is presented. The optical system was established based on a single long metrology grating. The large fringe multiplication was achieved by properly selecting two high-order diffraction beams to form a fringe pattern. The fringe pattern collected by a linear array was first tailored to a few multiples of fringes in order to suppress the effect of the energy leakage on phase-extracting precision when the fast Fourier transform (FFT) algorithm was used to calculate its phase. Thus, the phase-extracting precision of a tailored fringe pattern by FFT was greatly improved. Based on this, a novel subdividing method, which exploited the time-shift property of FFT, was developed to subdivide the fringe with large multiple and high accuracy. Numerical results show that the system resolution reaches 1 nm. The experimental results obtained against a capacitive sensor in the sub-mm range show that the measurement precision of the system is less than 10 nm.

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Section: System Optical Configurationmentioning

confidence: 99%

“…But its profile was irregular due to the existence of various noise sources. For a non-perfect fringe signal like this, the subdividing error would be large if the conventional subdividing method based on two channels of orthogonal signals was used [7,8].…”

Section: Experimental Demonstrationmentioning

confidence: 99%

Research on long-range grating interferometry with nanometer resolution

Chu

Lu²,

Zhao

2007

Meas. Sci. Technol.

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“…For example, in coarse-fine motion platform, grating can be used in the feedback of coarse motion platform's large stroke linear movement. In recent years, with the increase of ultra-precision grating's processing technology, the interferometric technique based on high precision and wide range grating is gradually applied in nano measurement [2] [3]. Compared with the nanometer precision measurement and positioning based on traditional interferometer, grating measurement is insensitive to pressure, temperature, CO 2 content and air disturbance so that there is no need to use air sensors to compensate environmental error.…”

Section: Introductionmentioning

confidence: 99%

Research of Clock Pulse Interpolation Technology Based on Constant Acceleration Model

Gao¹,

Hu²,

Zhu³

et al. 2017

dtetr

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Abstract. Clock pulse interpolation method which relies on the software implementation is widely used in the measurement occasions when grating is used. For the displacement less than a grating pitch, common method is to estimate it using adjacent cycle information based on constant speed model or linear model. When the measured object moved with constant speed, these two methods would not introduce errors. However, when the measured object moved with constant acceleration or constant jerk, principle errors would be produced in these two methods. For this problem, this paper developed a method to measure the displacement less than one cycle in clock pulse interpolation method's applications based on constant acceleration model. Simulation result demonstrated that this method will not introduce error when the measured object moves with constant acceleration, and its overall effect is better than the estimation effect using constant speed model or linear model when the object moves with constant jerk.

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“…The sensitivity of moiré interferometry has been doubled by a new optical configuration proposed by Lin [81] . In the new configuration, the incident laser beam is perpendicular to the specimen, and +1 and -1 diffraction order of the incident beam is reflected back to the original incident direction using two mirrors.…”

Section: Development Of Moiré Interferometrymentioning

confidence: 99%

Development of a transparent indenter measurement system and indentation analysis for material mechanical property evaluation

Feng¹

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Since Tabor showed the application of the spherical indentation approach to obtain material post-yielding true stress-strain curves, the indentation technique has been investigated to determine mechanical properties besides hardness measurement. With the development of various thin film materials, depth-sensing indentation is often applied to evaluate mechanical properties of thin film materials. However, indentation testing is a complicate mechanical process and analytical solutions are difficult to obtain. As a result, much of the understanding of the indentation process has been acquired through experiments and finite element simulations. Thus accurate measurement of indentation parameters is critical in the determination of surface mechanical properties using indentation method. In this research, a Transparent Indenter Measurement (TIM) method was developed for material inspection and mechanical property measurement. The TIM method is capable of on-site, in-situ, (i) mechanical property measurement (hardness, Young's modulus, yield strength and post-yielding stress strain data) of material samples/machined parts and (ii) qualitative inspection of material surface conditions. The residual surface deformation after spherical indentations was first investigated on IN783 superalloy samples using phase-shifting moiré and Twyman-Green interferometry. The elastic-plastic boundary was identified based on the characteristic of the out-of-plane deformation fringe patterns. Then using the measured in-plane deformation, yield strength of the tested material was obtained. Using the TIM system, real-time in-situ measurement of indentation-induced out-of-plane deformation and contact radius are directly measured during an indentation process. Coupled with elastic recovery theories and 2D finite element analyses, a procedure was developed to determine the material stress-strain curve. It is also demonstrated that the TIM method is suitable for debonding inspection of thin film materials.

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A new moiré interferometer for measuring in-plane displacement

Cited by 3 publications

References 10 publications

Research on long-range grating interferometry with nanometer resolution

Research on long-range grating interferometry with nanometer resolution

Research of Clock Pulse Interpolation Technology Based on Constant Acceleration Model

Development of a transparent indenter measurement system and indentation analysis for material mechanical property evaluation

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