Tonpilz transducers designed using single crystal piezoelectrics

Abstract

New single crystal piezoelectrics were investigated as improved transducer materials. Single crystals take advantage of crystallographic engineering to produce high piezoelectric and electromechanical coupling coeflicients. Single crystal lead magnesium niobate-lead titanate (PMN) was substituted for the piezoelectric ceramic section of a tonpilz transducer design, in order to reduce length and improve bandwidth and output power. Predictions and measurements of transmit performances were made for purposes of comparison to a PZT-8 design. ATlLA finite element modeling was used to predict vibration modes, coupling coeflicient, head displacement, transmit voltage response, and stress levels in the transducer. Tonpilz elements were then fabricated, tested and analyzed. The performance of the single crystal device was shown to provide the same or improved response over the PZT-8 transducer at a reduced transducer length.

Low Frequency Range Tracking Transducer

“…2 nd Generation PMN-PIN-PT does not requirean applied dc bias field and provides greater stability under drive and prestress [12] than the 1 st Generation PMN-PT materials 1 Frequencies and sound pressure levels have been normalized to f 0 and SPL 0 , respectively, to facilitate public release of this information. used in References [6], [7], and [8]. Figure 1 shows the LF RTT at various stages of its construction.…”

“…Lead magnesium niobate-lead titanate (PMN-PT, or 1 st Generation) and lead magnesium niobate-lead indium niobate-lead titanate (PMN-PIN-PT, or 2 nd Generation) Piezocrystals, poled along the <001> crystallographic axis and operated in the 33-mode, have been shown to produce these size and weight reductions, source level improvements and bandwidth increases in tonpilz and cylinder transducers [6][7][8]. Reference [9] details how, by changing the orientation of the poling field and the crystal cut relative to the crystallographic axes, entirely new piezoelectric modes of operation can be realized that do not exist in PZT ceramics.…”

Characterization of Mn-modified Pb(Mg1∕3Nb2∕3)O3–PbZrO3–PbTiO3 single crystals for high power broad bandwidth transducers

“…This offset effectively increases the coercive field ͑E C ͒ and reduces or clamps domain wall motion/mobility. 2,3 A consequence of these dopants, however, is a reduction in electromechanical coupling and piezoelectric activity, with k 33 values less than 70% and piezoelectric strain coefficients d 33 's on the order of 200-350 pC/ N, 4 so limits the bandwidth of transducer since the power and bandwidth capabilities of the transducer are functions of the mechanical quality and electromechanical coupling factors 5,6 . Recently, domain engineered ͗001͘ oriented single crystal perovskites have been demonstrated to possess ultrahigh electromechanical couplings k 33 Ͼ 90% and high piezoelectric coefficients d 33 Ͼ 1500 pC/ N. However, the relaxor-PbTiO 3 ͑PT͒ crystals exhibit low mechanical quality Q's ͑Ͻ100͒ and coercive fields ͑E C ϳ 2-3 kV/ cm͒, typical of "soft" piezoelectric behavior.…”

Large signal response and harmonic distortion in piezoelectrics for SONAR transducers

“…In particular, the high coupling coefficient leads to a wide frequency bandwidth in a device, which in-turn improves the resolution of the transducer. Increased resolution is of great interest in medical ultrasound transducers [6][7][8] as well as underwater SONAR projectors [9][10][11].…”