Tube-type double-parabolic-reflector ultrasonic transducer (T-DPLUS)

[摘要] There is no doubt that a variety of ultrasonic applications is supported by ultrasonic transducer technology. One of the most commonly used ultrasonic transducers is the boltclamped Langevin-type transducer (BLT). The BLT is a highpower transducer in which laminated piezoelectric ceramics are sandwiched between metal blocks and tightened with a bolt. BLTs are widely used in high-power ultrasound devices, such as actuators [1], cleaners [2], and grinders [3]. However, a BLT has only a single working frequency lower than several hundred kilohertz, which limits the application possibilities. Recently, Chen et al. studied a double-parabolic-reflector ultrasonic transducer (DPLUS) [4–7], which consists of a lead zirconate titanate (PZT) ring, double-parabolic reflectors (1st and 2nd reflectors), which share the same focal point, and a thin waveguide. The 1st reflector focuses the incident plane wave from the PZT ring, and the 2nd reflector reflects the ultrasound and turns it into an in-phase plane wave, which propagates into the thin waveguide. This process enhances the energy density of the ultrasound because the size of the 2nd reflector is smaller than that of the 1st reflector. The enhanced ultrasound is finally radiated from the tip of the thin waveguide. DPLUS can realize wideband (20 kHz to 2.5 MHz), high-intensity (several megapascals) ultrasound generation near the tip of the thin waveguide. These characteristics are difficult to achieve with conventional transducers containing BLTs. Hence, DPLUS expands potential applications of ultrasonic technology in various fields, such as ultrasound therapeutics [7], medical imaging, and ultrasonic tweezers.

[学科分类] 声学和超声波

[关键词] Ultrasonic transducer;Parabolic focusing;Minimally invaseive treatment;Acoustic waveguide;DPLUS