Miniature conical transducer realized by excimer laser micro-machining technique

This paper presents the fabrication and characterization of a miniature conical transducer that can be used as an acoustic emission sensor for localized measurements. The development of the miniature conical transducer is based on the commercial NBS conical transducer and the micro-fabrication capability of an excimer laser. The conical PZT element, which is the key component in the transducer, is fabricated by an excimer laser micro-machining workstation with a specially designed laser mask and a new work piece rotation machining technique. Small conical piezoelectric elements with end surface around 200 mum in diameter are directly fabricated out of a polarized PZT ceramic plate. The miniature conical transducer is then constructed. Standard acoustic emission measurements are carried out to characterize the performance of the transducer. Very good results are observed which indicate that the miniature conical transducer can be successfully used for measuring high-frequency dynamic surface motion. (C) 2001 Elsevier Science B.V. All rights reserved.