Laser ultrasonic synthetic aperture focusing imaging device and method based on annular beam

Abstract

The invention discloses a laser ultrasonic synthetic aperture focusing imaging device and method based on an annular beam. The device comprises an excitation light source system, a detection light source system, a signal output and control system and a system to be detected. By using a conical lens in the excitation light source system, a single-point excitation light beam is changed into an annular excitation light beam. After a beam combiner in the detection light source system combines a detection light beam and an annular excitation light beam to be concentric, an interferometer is used for obtaining vibration information of the surface of a to-be-detected sample. Finally a stepping motor in the to-be-detected system is used for completing two-dimensional scanning on the surface of the to-be-detected sample. According to the device, the scanning time is reduced and the working efficiency of the system is greatly improved while the identification capability and the imaging resolution of small defects in the detected defects are improved.

Description

technical field [0001] The invention belongs to the field of laser ultrasonic detection, in particular to a laser ultrasonic synthetic aperture focusing imaging device and method based on a ring beam. Background technique [0002] At present, in industrial production, ultrasonic testing is generally used to detect the defects of metal aluminum products. However, due to the complex structure of metal aluminum products, it is difficult to use conventional ultrasonic testing methods to detect defects. The traditional laser ultrasonic testing technology mainly relies on couplant to couple the ultrasonic transducer with the test sample, but due to the complex shape of the test sample, it cannot meet this requirement, so the use of traditional ultrasonic testing methods has certain limitations. [0003] In order to solve the limitations of traditional ultrasonic contact detection, research on non-contact ultrasonic detection is imminent. Air-coupled ultrasonic testing, electromag...

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Problems solved by technology

[0002] At present, in industrial production, ultrasonic testing is generally used to detect the defects of metal aluminum products, but due to the complex structure of metal aluminum products, it is difficult to use conventional ultrasonic testing methods to detect defects

[0006] However, the previous laser ultrasonic SAFT detection technology used single-point excitation and single-point scanning, and the scanning speed was slow and time-consuming.

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