High Frequency Piezocomposite And Methods For Manufacturing Same

Abstract

A transducer with triangular cross-sectional shaped pillars is described for suppressing lateral modes within a composite, and a method for producing the same. According to one aspect of the present application, a plurality of triangular cross-sectional shaped pillars extends outwardly from a substrate and form an array of pillars. The resulting array of pillars is configured to suppress the lateral modes of the transducer at higher operating frequencies, such as, at or above 15 MHz, at or above 20 MHz, or at or above 30 MHz.

Description

[0001]This application claims the benefit of U.S. Provisional Application No. 60 / 983,263 filed on Oct. 29, 2007, which application is herein incorporated by reference in its entirety.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]This invention relates to piezoelectric composites, and more particularly to piezoelectric composites for high-frequency ultrasound applications and methods of manufacturing such composites.[0004]2. Background Art[0005]Typically, high quality medical imaging uses ultrasonic transducers or transducer arrays that posse the properties of good sensitivity and wide frequency bandwidth. Conventional transducers utilizing monolithic piezoelectric material such as, for example, lead zirconate titanate (“PZT”), typically exhibit a large acoustic impedance mismatch between the transducer and the medium under test, such as, for example, water, human tissue, and the like. To overcome this problem, piezoelectric composites that are made of individual sm...

AI Technical Summary

Benefits of technology

The present patent application describes a transducer with triangular shaped pillars that can suppress lateral modes in a piezoelectric composite. The triangular pillars are positioned in rows parallel to the substrate and can be paired with each other. The method for producing the transducer involves applying an electric signal to the substrate and using the triangular pillars to create an ultrasonic wave emission pattern at higher frequencies. The technical effect of the invention is to improve the performance and efficiency of ultrasonic waves in the transducer.

Problems solved by technology

Unfortunately, developing a high-frequency (>15 Hz) ultrasound transducer is also very challenging due to the extremely small pillar dimensions required in order to avoid significant lateral resonances in the piezoelectric composite.

Conventionally, the design of piezo-composites is limited by the blade size limit of micro-dicing saws or other conventional apparatuses that are used to cut the bulk piezoelectric into composite pillars.

It is very difficult using conventional dice and fill techniques to sufficiently reduce the size / spacing of the composite pillars enough to push the lateral resonances outside the operating bandwidth of a transponder that is configured to operate at high frequencies.

Developing a suitable acoustic lens, however, can be very challenging because the lens materials commonly used for lower frequency transducers are far too attenuating at frequencies at higher frequencies.

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