Surface three-dimensional measurement system with tunable beat-wave linear scanning

Abstract

The invention discloses a wide-range high-resolution surface three-dimensional measurement system with tunable beat-wave linear scanning, which belongs to the technical field of optical measurement and comprises a broadband light source, two optical fiber isolators, three diaphragms, three auto-collimating lenses, two diffraction gratings, seven plane cylindrical lenses, two linear array photoelectric couplers, a 3-dB coupler, a beam splitter, a longitudinal micro-motion worktable, a transverse micro-motion worktable, a data acquisition card, a signal generator, drive control, a computer and result output. A beat-wave plate is used for scanning a surface to be measured, one linear array photoelectric coupler is used for detecting beat-wave interference signals, the range is half of beat-wave length, the other linear array photoelectric coupler is used for detecting single-wavelength interference signals to determine resolution, and the system is provided with wide range and high resolution. Different ranges can be obtained by adjusting the beat-wave length. Surface three-dimensional measurement can be complete with only one-dimensional scanning, so that mechanism is simplified, and measurement speed is increased. By means of common-path interference, the system is high in interference resistance and suitable for online measurement.

Description

technical field [0001] The invention relates to the field of optical measurement, in particular to a large-range and high-resolution surface three-dimensional measurement system. Background technique [0002] The existing literature close to this technology has the following two: [0003] [1] D.P.Hand, T.A.Carolan, J.S.Barton, and J.D.C.Jones. "Profile measurement of optically rough surfaces by fiber-optic interferometry", Opt.Lett., Vol.18, No.16, 1993, P.1361-1363 .(Optics Letters, Vol. 18, No. 16, P.1361-1363) [0004] The technical principle of literature [1] is as follows: figure 1 shown. [0005] The light emitted by the semiconductor laser passes through the Faraday isolator and the fiber 3dB-coupler, and then reaches the measuring head. The measuring head is a Fizeau interferometer. A part of the light is reflected by the end face of the fiber as the reference light, and the other part of the light is focused by the self-focusing lens. Projected onto the measured...

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Problems solved by technology

[0016] 2. The measurement range is limited by the wavelength λ of the incident light wave. The measurement range is very small, less than λ / 2, and the discontinuous surface whose step height is greater than half the wavelength cannot be measured.

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