Hewlett-Packard Company

Henry Yoshida

Michael Greenstein

Mir S Seyed-Bolorforosh

Turuvekere R Gururaja

A Z-axis backing layer for an acoustic transducer is provided, which comprises a matrix of electrical conductors disposed in parallel and potted within an electrically insulating acoustic backing material. The acoustic transducers are disposed on a first end of the backing layer, with each individual transducer element connecting electrically to a respective one of the conductors. At the other end of the backing layer, the conductors connect electrically to a corresponding circuit element. The backing layer is fabricated from a plurality of leadframes each having an outer frame member and a plurality of conductors extending in parallel across the leadframes terminating at the frame members at opposite ends thereof. The plurality of leadframes are stacked such that respective conductors of adjacent ones of the leadframes are disposed in parallel with a space provided between the respective conductors equivalent to a width of one of the leadframes. Acoustic backing material is poured onto the stacked plurality of leadframes to completely fill the spaces between conductors. The frame members and excess acoustic backing material are then removed from the stacked and poured plurality of leadframes.

Method for fabricating a Z-axis conductive backing layer for acoustic

A tunable ultrasonic probe includes a body of a first piezoelectric material acoustically coupled in series with a body of a second piezoelectric material. The second piezoelectric material has a Curie temperature that is substantially different than that of the first piezoelectric material. Preferably, the first piezoelectric material is a conventional piezoelectric ceramic, such as lead zirconate titanate, while the second piezoelectric material is a relaxor ferroelectric ceramic, such as lead magnesium niobate. At an operating temperature of the probe, the first piezoelectric material has a fixed polarization. In contrast, the second piezoelectric material has a polarization that is variable relative to the fixed polarization of the first piezoelectric material. A preferred novel arrangement of electrodes electrically couples the bodies in parallel with one another. An oscillating voltage for exciting the acoustic signals in the probe is coupled with the electrodes. The polarization of the second piezoelectric material is variably controlled by a bias voltage coupled with the electrodes. In a preferred embodiment, the bias voltage has a reversible electrical polarity for selecting one resonant frequency from a plurality of resonant frequencies of the probe. In another preferred embodiment, the bias voltage source has a variable voltage level for selecting at least one of a plurality of resonant frequencies of the probe.

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San Jose, CA, United States of America

Henry Yoshida