Lighting system and method used for dark field detection of defect in spherical optical element surface

Abstract

The invention discloses a lighting system and method used for dark field detection of a defect in a spherical optical element surface. The lighting system comprises a spherical light source, a light source support, an optical element to be detected, an optical element multidimensional holding device, a microscopic imaging system, a charge coupling element, a computer and a motor, wherein the spherical light source comprises a uniform face light source and a zoom lens group lens barrel, a plurality of spherical light sources are circlewise arranged on the light source support at equal intervals, a zoom adjusting component comprises a zoom lens group lens barrel, a front lens fixing group, a zoom lens group, a back lens fixing group, a zoom lens barrel, a gear and a sliding rail; the optical element to be detected and the holding device are arranged below the light source support, the microscopic imaging system and the charge coupling element are arranged above the light source support, and the light axis of the microscopic imaging system, the circle centre of a circular surface formed by a plurality of light sources, and the sphere centre of the optical element to be detected are coaxial. According to the dark field lighting for defect detection in the spherical optical element surface, an imaging is a bright defect image in the dark background, the contrast ratio is good, thus being easy for subsequent image processing.

Description

technical field [0001] The invention belongs to the technical field of surface defect detection of optical elements, in particular to an illumination system and method for dark field detection of surface defects of spherical optical elements. Background technique [0002] With the further development of science and technology, the requirements for optical components are getting higher and higher, especially in high-precision components such as lithography lenses and laser fusion chips, it is necessary to do precise and quantitative detection of surface defects of optical components detection. [0003] For defect detection at home and abroad, the visual method, low-pass and high-pass filter imaging methods, adaptive filter imaging methods, and angular spectrum analysis methods are basically used. However, most of these methods are only theoretical solutions, and are often limited by technical obstacles such as limited field of view and difficulty in quantification, making it...

AI Technical Summary

Problems solved by technology

However, for spherical optical elements, it is still at the level of human eye detection, with poor repeatability and quantitative detection.

When using the same illumination source as the plane detection to detect the spherical optical element, because the spherical optical element has a certain radius of curvature, a white reflective spot will be formed on the CCD (charge coupled device), and the size of the spot varies with the curvature radius of the spherical optical element, The uneven situation changes, it is difficult to realize dark field illumination, and it is impossible to carry out follow-up detection

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