An inner coaxial autofocus device, method and system based on spectral confocal

Abstract

The invention discloses an internal coaxial autofocus device based on spectral confocal, comprising: a polychromatic light source, a dispersion lens group, a light collimating lens group, a first beam splitter and a microscopic objective lens arranged in sequence along the distance measuring optical path ; The dispersive lens group is used to split the distance measuring light beam; the light collimating lens group makes the beam of the target wavelength parallel and collimated; the objective lens focuses the beam of different wavelengths on different positions on the optical axis, and makes the beam of the target wavelength coincide with the incident The focal plane of the imaging light of the eyepiece coincides; the first beam splitter realizes the coaxial coupling between the optical path of the ranging light and the optical path of the imaging light; the spectrometer collects the spectral information of the ranging light focused on the surface to be measured, so that the surface to be measured is in the target The focal plane of the beam of wavelength achieves microfocusing. The optical path of the autofocus system and the optical path of the microscope system are highly coupled and coaxial, the structure is simple and compact, and the degree of integration of optical components is improved. The detection method based on spectral confocal improves the speed and accuracy of autofocus.

Description

technical field [0001] The invention belongs to the technical field of automatic optical detection, and in particular relates to an internal coaxial autofocus device based on spectral confocal, an internal coaxial autofocus method based on spectral confocal, and an internal coaxial autofocus method based on spectral confocal Coaxial autofocus system. Background technique [0002] Autofocus device is the premise and core of AOI detection. When AOI equipment inspects samples to be tested (display panels, wafers, PCBs, etc.), it is necessary to obtain clear microscopic enlarged images of the target area, and then use image processing technology to identify defects in the target area. However, due to the structure of the target sample itself, the height difference of different target areas may exceed the depth of field of the microscope system. Therefore, an autofocus device is required to measure the defocus of the target area and feed back the obtained information to the cent...

AI Technical Summary

Problems solved by technology

[0012] In the above-mentioned existing autofocus devices, the external structure is complicated and the cost is high, and the optical path using the triangular distance measurement method may lead to a blind area of ​​the field of view, and the measurement accuracy is poor; while the internal coaxial structure also uses the triangular distance measurement method The range measurement method, or the spot shape of different imaging surfaces to judge the defocus information, the area array image processing takes a long time, and it is difficult to quickly and accurately achieve autofocus

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