TW200733776A - Analytical back scattering arrayed ultrasound transducer (ABSAUT) - Google Patents

Abstract

This patent proposes a new type of focusing ultrasound transducer. It is designed for detecting internal defects of a sample in an analytic and quantitative way via multiple back scattering ultrasound signals collection. It essentially follows the basic structure of a conventional focusing ultrasound transducer which has an acoustic lens with a concave spherical surface at one end, and an attached PZT layer for ultrasound generation at the other end. However, there are two fundamental and original innovations in the construction of ABSAUT make it a more powerful and advanced transducer for ultrasound inspection and acoustic imagining. First of all, the PZT layer is machined by an excimer laser to form an annular arrayed transducer. Hence, by using the phased array modulation on triggering time, one can electronically control the incident waves. Secondly, a VDF film is attached to the concave spherical surface and is acting like a matching layer to enhance the wave transmission from the acoustic lens to the coupling fluid. Furthermore, the electrodes on both sides of the PVDF film are patterned by an excimer laser in such a way that a number of hydrophones are formed and are distributed on the concave spherical surface. When the incident acoustic waves are reflected by the sample's surface and/or scattered by the internal defects in the solid sample, and the back scattering ultrasounds are detected by the PVDF hydrophones and the waveforms are acquired. By analyzing the recorded back scattering waveforms from PVDF hydrophones, more information could be collected.