213 Vibration Characteristics of Unimorph Type Circular Piezoelectric Vibrator

Parametric speakers generate narrow directive sound field using modulated ultrasonic. Small size parametric speakers have a problem in sound quality. Demodulated audible sounds by parametric speakers have poor sound pressure in low and middle frequency bands due to the theory of the finite amplitude sound. The sound pressure of a demodulated sound monotonically increases as the frequency of the demodulated sound increases. To solve these problems, an ultrasonic transducer having a wide single peak or more than two peaks must be fabricated. Our previous paper proposed to use two resonant peaks which are close each other. Two close resonant peaks were obtained by two same sized diaphragms linked each other by a specially designed rod. In this paper, a transducer was developed to better structure which has durability against strong mechanical forces and two electrical inputs to control resonant modes of vibration. Durability was improved by optimization of the junction structure. The resonant mode control was enabled by a phase difference between two electrical signals applied to piezoelectric elements on two diaphragms. We succeeded in boosting mid-range sounds, by the newly developed transducer.

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“…3. The homogeneous and inhomogeneous equations expressing the vibration of a disk in a steady state are represented as [14][15][16][17][18],…”

Section: Basic Theory Of Design To Develop Transducermentioning

confidence: 99%

Piezoelectric transducer with resonant modes control for parametric speaker

Kuroda

Oikawa

2018

Acoust. Sci. & Tech.

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“…In contrast, diaphragm 2 consists of the metal and the piezoelectric element, so its bending stiffness is [14] D ¼ D 0 þ D 1 ;…”

Section: Appendix: Calculation Of the Biharmonic Equation Of The Bendmentioning

confidence: 99%

Design of an ultrasonic piezoelectric transducer having double-linked diaphragms for parametric speakers

Kuroda

Oikawa

Yamasaki

et al. 2015

Acoust. Sci. & Tech.

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Small highly efficient ultrasonic transducers are in high demand to fabricate compact parametric speakers. We focus on small piezoelectric transducers that can be used for ultrasonic emitters of parametric speakers. Typical small piezoelectric transducers have piezoelectric boards and radial cones. We propose a transducer consisting of a unimorph diaphragm and a flat metal plate. This structure gives two resonant peaks, which are determined by the physical parameters and dimensions of the diaphragms, the flat plate, and their junction structure. Controlling these resonant peaks is one approach to fabricating transducers having the ideal frequency response of the sound pressure for parametric speakers. We devised a design to control these two resonant peaks by adjusting the junction structure of the diaphragm and the flat plate. Using the results of a theoretical analysis, we designed an improved transducer that satisfies the ideal frequency response for parametric speakers.

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213 Vibration Characteristics of Unimorph Type Circular Piezoelectric Vibrator

Cited by 2 publications

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Piezoelectric transducer with resonant modes control for parametric speaker

Piezoelectric transducer with resonant modes control for parametric speaker

Design of an ultrasonic piezoelectric transducer having double-linked diaphragms for parametric speakers

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