A 3D online surface interferometry system with super lateral resolution based on spectral dispersion full field

Abstract

The invention discloses a three-dimensional on-line interferometric measurement system for a surface with super lateral resolution based on spectral dispersion full field, belonging to the field of optical measurement. The system consists of broadband light source, isolator, optical fiber and optical fiber connector, spherical and cylindrical lens, beam splitter, rectangular prism, aperture, grating, reflector, area detector, photodetector, Fabry-Perot Filter, piezoelectric ceramics, signal processing, feedback control, data acquisition card, computer, translation stage and translation stage drive, result output, etc. The grating disperses the broadband spectrum into a light sheet with continuous distribution of wavelengths in the transverse direction, and the expanded beam is vertically incident on the surface to be measured for full-field measurement; two wavelengths are used to measure steps with a height difference greater than half the wavelength and grooves with a large aspect ratio Surface; Fabry-Perot filter is used to achieve super lateral resolution measurement; feedback control compensates environmental interference to make the system suitable for online measurement, and the measurement results are accurately traceable to the wavelength reference, and are not affected by the spectral drift of the light source.

Description

technical field [0001] The invention relates to the field of optical measurement, in particular to a three-dimensional on-line interferometry system for surfaces with super lateral resolution based on spectral dispersion full field. 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. "Profilemeasurement of optically rough surfaces by fiber-optic interferometry", Opt.Lett., Vol.18, No.16, 1993, P.1361-1363. (Optics Letters, Volume 18, Issue 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. 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 ...

AI Technical Summary

Problems solved by technology

[0015] 1. The light spot scans the surface to be measured for three-dimensional surface measurement. The light spot needs two-dimensional scanning to complete the surface three-dimensional measurement. The scanning mechanism is complicated and the measurement speed is slow.

[0016] 2. The lateral resolution of the measurement depends on the diameter of the spot, which is limited by the diffraction limit. Therefore, the lateral resolution depends on the diffraction limit, and it is difficult to obtain measurement results with high lateral resolution.

[0017] 3. It is not possible to measure surfaces with steps with a height difference greater than half a wavelength and grooves with a large aspect ratio

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