Phase shifting angle interferometer

Eves, B J; Leroux, I D; Cen, A J

doi:10.1088/1681-7575/acee82

Cited by 2 publications

(4 citation statements)

References 18 publications

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“…Given detailed knowledge of the surface form, one could correct for these measurand differences rather than expanding uncertainties to cover them. Such information is most easily obtained using an interferometer and NRC recently built a PSI specifically to measure both surface form and plane angle [10]. We have found that it has a lower plane angle measurement uncertainty (ignoring measurand differences) than our autocollimator.…”

Section: Discussionmentioning

confidence: 99%

“…As the surface deforms, the different choices of f lead to differences in reported angle on the scale of arcseconds. The x-axis angles are more sensitive to the choice of f than the y-axis angles, because the symmetry of our mirror mount leads to a deformation roughly symmetric about a horizontal line [10]. The mirror angle distribution ρ M therefore roughly symmetric for y but markedly asymmetric in x.…”

Section: Symbolmentioning

confidence: 96%

“…Investigating the impact of surface form on autocollimators requires the ability to vary and characterize the surface form. We have therefore developed an angle interferometer and a simple deformable target surface [10]. The angle interferometer uses phase-stepping interferometry to measure the topography of the mirror under test and to report the normal vector obtained from a least-squares plane fit to that topography.…”

Section: Impact Of Surface Form On Angle Distributionmentioning

confidence: 99%

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Autocollimators: plane angle measurand ambiguities and the impact of surface form

Eves,

Leroux

2023

Metrologia

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A phase shifting interferometer and a deformable mirror were used to study the impact of surface form on autocollimators, which detect the orientation of a plane reflecting surface. As real surfaces are not strictly planar, autocollimators must reduce a distribution of local surface orientations to a single reported angle, implicitly defining a measurand. Plausible choices of the summary statistic used to collapse an angle distribution to a single number can disagree by \SI{4}{\arcsecond} for a surface with a \SI{35}{mm} diameter and \SI{130}{nm} standard deviation from the best-fit plane. Combining a general framework for specifying autocollimator measurand definitions with Monte-Carlo simulation of random test surfaces yields estimates of the plausible differences between autocollimator measurands as a function of surface deformation amplitude, and shows the existence of three separate classes of measurands according to their sensitivity to subsets of the Zernike polynomials. Uncertainties due to surface form and measurand ambiguity can be eliminated by explicitly specifying a plane angle measurand for imperfect surfaces, such as a least-squares plane fit realized using an interferometer.

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Section: Discussionmentioning

confidence: 99%

Section: Symbolmentioning

confidence: 96%

Section: Impact Of Surface Form On Angle Distributionmentioning

confidence: 99%

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Autocollimators: plane angle measurand ambiguities and the impact of surface form

Eves,

Leroux

2023

Metrologia

Self Cite

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“…This method of measuring the phase is generally more accurate, but the corresponding set of equipment is also more expensive and complex. This method generally has a small range but high accuracy [ 6 , 9 , 97 , 98 , 99 , 100 , 101 , 102 , 103 , 104 , 105 , 106 , 107 , 108 , 109 , 110 , 111 , 112 ], and in order to further investigate its mechanism and error correction, an independently characterized angle measurement system that is useful for angle calibrations is proposed [ 113 ]. As for the environmental effect, measurement sensitivity can be improved through immersing the beta-barium borate plate in grapeseed oil, which can avoid deliquescence in humidity [ 114 ].…”

Section: High-precision With Single Axismentioning

confidence: 99%

A Review: High-Precision Angle Measurement Technologies

Wang,

Ma,

Cao

et al. 2024

Sensors

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Angle measurement is an essential component of precision measurement and serves as a crucial prerequisite for high-end manufacturing. It guides the implementation of precision manufacturing and assembly. The current angle measurement methods mainly focus on multiple axes, high precision, and large measurement ranges. This article introduces the technology of angle measurement from the perspectives of single-axis and multi-axis measurement schemes. Firstly, the single-axis measurement scheme is primarily achieved through optical methods, such as encoder discs that measure energy changes and interferometric phase changes, as well as mechanical, electromagnetic, and inertial angle measurement methods, among which interferometric methods offer the highest accuracy, with high cost, and encoder discs provide the largest measurement range with an ordinary price. Secondly, in the multi-axis measurement scheme, autocollimation instruments, including plane mirrors, gratings, and self-designed targets, are the main options. Although grating encoders can achieve three degrees of freedom in angle measurement with an ordinary price, they are limited in terms of measurement range and sensitivity compared to self-designed targets. Lastly, artificial intelligence assistance precision measurement is increasingly being embraced due to significant advancements in computer performance, making it more convenient to identify the relationship between measured values and detection values. In conclusion, angle measurement plays a crucial role in precision manufacturing, and the evolving and improving technologies provide the manufacturing industry with greater choices. The purpose of this review is to help readers quickly find more suitable technical solutions according to current application requirements, such as single/multiple axes, accuracy level, measuring range, budget, etc.

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Phase shifting angle interferometer

Cited by 2 publications

References 18 publications

Autocollimators: plane angle measurand ambiguities and the impact of surface form

Autocollimators: plane angle measurand ambiguities and the impact of surface form

A Review: High-Precision Angle Measurement Technologies

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