Wavelength scanning confocal micro-displacement measurement device and method

Abstract

The invention provides a wavelength scanning confocal micro-displacement measurement device and a method. In a confocal microscope optical path system, a wavelength tunable laser is used for carrying out illumination; a Fresnel zone plate is used for carrying out focus point illumination; according to the axial color difference focal shift characteristic, axial scanning of focus light spots is achieved through wavelength scanning; a confocal pinhole photoelectric detection unit is used for detecting confocal axial optical chromatography response output; for the disperse wavelength lambda<n> = lambda<min> + (n-)deltalambda, n = 1, 2, ..., 11, obtaining the axial optical chromatography displacement-intensity response, wherein the lambda<min> is the wavelength lower limit, the wavelength upper limit is lambda<max> = lambda<min> + 10deltalambda, and the deltalambda is the wavelength stepping interval; peak value positions of the optical chromatography response curves form a linear calibration relation searching table of illumination wavelengths and axial displacement; and fine wavelength scanning is executed for each characteristic point of a to-be-measured sample for once, and actual displacement of each point is calculated according to the peak value of each response curve and the searching table. Thus, measurement of micro-displacement or relative height is finished, and the method is suitable for precise measurement of micro displacement, film thickness, nano steps and the like.

Description

technical field [0001] The invention belongs to the technical field of precision measurement, in particular to a wavelength-scanning confocal micro-displacement measurement device and method. Background technique [0002] Confocal Microscopy is the most typical method to realize optical tomography. The earliest confocal microscopy imaging device was proposed by M.Minsky, a junior researcher at Harvard University in the middle and late 1950s, and confocal microscopy imaging was developed. The original prototype of the device was granted a US invention patent in 1961. Confocal microscopy has two main advantages, namely high imaging resolution characteristics and axial optical tomography capabilities. The emergence of confocal microscopy technology has revolutionized the basic principles of traditional wide-field optical imaging. Non-contact and non-destructive optical tomography can be realized through three-point conjugate scanning imaging, especially the emergence and devel...

AI Technical Summary

Problems solved by technology

The above two types of methods rely on precision mechanical movement to achieve scanning, so the imaging and measurement speed of the confocal microscope are greatly limited, and the cost of large-stroke precision displacement is high. Neither of these two types of methods can achieve fast and precise scanning along the axial plane.

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