Super lateral resolution surface three-dimensional online interference measuring system based on spectral dispersion full field

Abstract

The invention discloses a super lateral resolution surface three-dimensional online interference measuring system based on a spectral dispersion full field, and belongs to the field of optical measurement. The system is composed of a broadband light source, an isolator, a fiber, a fiber joint, a spherical-surface and cylindrical-surface spectroscopes, spectroscopes, right-angle prisms, diaphragms, a raster, a reflector, a surface array detector, a photoelectric detector, a Fabry-Perot filter, piezoelectric ceramics, a signal processing circuit, a feedback control circuit, a data acquisition card, a computer, translation benches, a translation bench driving part, a result output part and the like. The raster disperses a broadband spectrum to form a mating plate whose wavelength is continuously distributed in a transverse direction, and the mating plat is incident vertically to a measured surface through beam expansion for full-field measurement; a surface provided with a step whose height difference is greater than a half-wavelength and a large-depth-to-width-ratio groove is measured by use of two wavelengths; super lateral resolution measurement is realized by use of the Fabry-Perot filter; and ambient interference is compensated through feedback control, the system is enabled to be suitable for online measurement, the measuring result can be accurately traced to a wavelength reference, and the influence of the drift of a light source spectrum is eliminated.

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. "Profile measurement of optically rough surfaces by fiber-optic interferometry", Opt. Lett., Vol.18, No.16, 1993, P.1361-1363. (Optics Letters (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 t...

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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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