Detecting device and detecting method for dark field cofocal subsurface based on coaxial two conical lenses

Abstract

The invention discloses a detecting device and a detecting method for dark field cofocal subsurface based on two coaxial conical lenses. Light emitted by a point light source passes through a collimating lens to form parallel light; the parallel light sequentially passes through a beam expander, a conical lens I and a conical lens II to form ring light; the ring light is converged to a to-be-tested sample by a beam splitting prism and an objective lens; reflected light and scattered light which are emitted by the to-be-tested sample pass through the objective lens and the beam splitting prismsequentially and enter a detection complementary diaphragm; the reflected light is shielded by the detection complementary aperture; the scattered light passes through the detection complementary diaphragm, a collecting lens and a detection pinhole sequentially and enters a photoelectric detector. The ring light illumination with adjustable duty factor is realized by adopting a beam expander and one group of symmetrically-putted coaxial conical lenses; dark field cofocus is realized by in combination with the detection complementary diaphragm; the problems of low signal-noise ratio, non-adjustable duty ratio of a shield type ring optical generator and great energy loss in the detection of the subsurface by an ordinary cofocal microtechnique are solved; the detecting device and the detecting method are suitable for subsurface nondestructive testing.

Description

technical field

[0001] The present invention relates to the technical field of optical precision measurement, and more specifically relates to a dark-field confocal subsurface non-destructive testing device and method based on a coaxial biconical lens with a variable duty ratio, which can realize the transformation from a common confocal microscope system to a dark field. Transformation of the field confocal microscopy system to achieve precise measurement of subsurface damage. Background technique

[0002] With the rapid development of modern science and technology, optical materials have been widely used, especially in cutting-edge science such as aerospace, national defense, military industry, information, microelectronics and optoelectronics, and become an indispensable and important material. The application of optical components is becoming more and more widespread, and higher requirements are put forward for the surface quality of optical components. This requires the...

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