Defect width calibration standardizing system and method in optical surface defect dark field detection

Abstract

The invention discloses a defect width calibration standardizing system and method in optical surface defect dark field detection. According to the invention, the association between the actual width of the object surface defect and the CCD (charge coupled device) imaging pixel width in defect detection is realized. The method disclosed by the invention is technically characterized in that in order to simulate the optical surface with a defect, a quartz calibration board engraved with a series of standard width scribed lines is manufactured, and the actual width of the scribed lines is calibrated by a scanning electron microscope; an optical surface defect dark field detection system is adopted, the quartz calibration board is moved by a precision guide rail in the optical surface defect dark field detection system, and the dark field gray-scale map of each calibration line is acquired in cooperation with CCD; and the gray-scale maps are subjected to feature recognition and feature extraction and compared with the actual width to establish a dark field objective image association function. After the dark field objective image association function is obtained, the width of the surface scratch can be calibrated by processing the image of the detected piece acquired under the same imaging conditions. Therefore, standard calibration of the micro-level or submicro-level defect on the optical surface is realized.

Description

technical field [0001] The invention relates to a scratch width calibration system and method in dark field detection of optical surface defects. Background technique [0002] With the development of modern optical technology, high-precision precision instrument systems have higher and higher requirements for the surface quality of optical components. Seriously affect the performance of the instrument system. Among them, there are strict requirements on the surface defects of precision optical components. The surface defects of precision optical components are usually only on the order of microns or even sub-microns, while the size of the components ranges from a few millimeters to hundreds of millimeters, or even larger. Therefore, compared with the scale of defects, the distribution of defects is extremely scattered, which brings challenges to the accurate and fast calibration of surface defects of optical components. [0003] At present, the detection of optical su...

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Problems solved by technology

These methods have more or less defects, such as it is difficult to detect large-caliber components due to the small field of view, the detection time is very slow, or the defects cannot be accurately calibrated, etc.

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