Design of Bone Conduction Implants Piezoelectric Transducer Based on Rhombus Mechanism for Magnetic Resonance Compatibility Improvement

Abstract

This study introduces a novel piezoelectric transducer for bone conduction implants that combines piezoelectric elements with a rhombus mechanism to enhance compatibility with magnetic resonance environments. To derive the optimal design of the rhombus structure, various parameters were investigated using theoretical analysis and finite element analysis. A theoretical model of the rhombus structure was employed to identify the parameters affecting displacement amplification magnitude. Based on this, a parametric analysis was performed to calculate the displacement amplification ratio according to these parameters. The results showed that as the beam thickness and width increased, the amplification ratio reduced, while with an increased length, the amplification ratio was increased. Therefore, the optimal rhombus structure for the transducer featured beam dimensions of 0.15 mm thickness, 2 mm width, 3.5 mm length, and 5.5° inclination. This configuration amplified piezoelectric element displacement by a factor of 7.02. The amplification ratio remained constant as long as the mass applied to the rhombus frame to control mechanical resonance did not exceed the blocking force of the piezoelectric element. When a mass of 0.3 g was applied to the frame, mechanical resonance occurred at a frequency of 2 kHz, making it suitable as a transducer for bone conduction implants.