Compact scanning confocal chromatic sensor enabling precision 3-D measurements

Abstract

This paper proposes a compact and lightweight scanning confocal chromatic sensor (SCCS) for robot-based precision three-dimensional (3-D) surface measurement applications. The integrated system design includes a 2-D fast steering mirror (FSM) to manipulate the optical path of a high precision 1-D confocal chromatic sensor (CCS). A data-driven calibration procedure is used to accurately combine the FSM deflection angles and the correspondingly measured distances to the sample surface in order to obtain a correctly reconstructed 3-D image. Lissajous scan trajectories are applied to enable efficient scans of the sample surface. The SCCS provides 3-D images at frame rates of up to 1 fps and a measurement volume of 0.35 × 0.25 × 1.8 m m 3 , as well as the measurement of arbitrary regions of interest. Using a calibration standard including structures with defined sizes, the lateral and axial resolutions are determined to 2.5 µm and 76 nm, respectively.

Longitudinal Mode Number Estimation of External Cavity Diode Laser Using Dual Periodic Grating for Optical Profiler System

“…Optical profilers capable of capturing the 2.5-dimensional shape of objects are in high demand, requiring enhanced measurement speed, high lateral and optical-axis resolution, and extended working distances. Various methods have been proposed to address these requirements [ 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 ].…”

“…Additionally, structures with a high aspect ratio are challenging to measure due to blocked response signals, such as reflected and scattered light, by the measuring object itself. Chromatic confocal sensors represent another commonly used method [ 12 , 13 , 14 ]. These sensors use chromatic aberration, leading to a trade-off between resolution and measurement range.…”

Measurement uncertainty evaluation of chromatic confocal displacement sensor

“…CCDS is widely used in optical metrology field due to its high precision and high resolution [3,4] . And it can be integrated into many detection systems.…”

Design and Research of Chromatic Confocal System for Parallel Non-Coaxial Illumination Based on Optical Fiber Bundle

“…Additionally, compared with other optical measurement techniques, such as the white-light interferometry [1,2], laser triangle method [3,4], grating projection method [5,6], and laser confocal method [7,8], chromatic confocal technology has no axial scanning, and its measuring efficiency and precision are higher. The application fields of chromatic confocal technology mainly include displacement and thickness measurements [9,10], flatness and roughness tests [11,12], defect and flaw detection [13,14], three-dimensional topography reconstruction [15,16], etc.…”