Thermoelastic expansion vs. piezoelectricity for high-frequency, 2-D arrays

• Published in: IEEE transactions on ultrasonics, ferroelectrics, and frequency control Vol. 50; no. 8; pp. 1065 - 1068
• Main Authors: Buma, T., Spisar, M., O'Donnell, M.
• Format: Journal Article
• Language: English
• Published: United States IEEE 01.08.2003; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Absorption; Acoustic arrays; Arrays; Chemical elements; Conversion; Dimethylpolysiloxanes; Elasticity; Equipment Design - methods; Equipment Failure Analysis; Ferroelectric materials; Frequency; Glass; Models, Theoretical; Noise levels; Optical films; Optical microscopy; Piezoelectric films; Piezoelectricity; Sensitivity and Specificity; Silicone resins; Silicones; Temperature; Thermoelasticity; Transducers; Two dimensional displays; Ultrasonography - instrumentation; Ultrasonography - methods; Ultrasound; Vibration
• ISSN: 0885-3010; 1525-8955
• DOI: 10.1109/TUFFC.2003.1226551

Optical generation using the thermoelastic effect has traditionally suffered from low conversion efficiency. We previously demonstrated increased efficiency of nearly 20 dB with an optical absorbing layer consisting of a mixture of polydimethylsiloxane (PDMS) and carbon black spin coated onto a glass microscope slide. In this paper we show that the radiated power from a black PDMS film is comparable to a 20 MHz piezoelectric two-dimensional (2-D) array element. Furthermore, we predict that a thermoelastic array element can produce similar acoustic power levels compared to ideal piezoelectric 2-D array elements at frequencies in the 100 MHz regime. We believe these results show that thermoelastic generation of ultrasound is a promising alternative to piezoelectricity for high-frequency, 2-D arrays.