Electromechanical Transducer Acoustic Impedance Matching

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Solution Overview

Problem

Existing electromechanical transducer devices face noise issues due to low-frequency ultrasonic waves easily passing through the substrate and causing signal-to-noise ratio degradation, particularly in wide-band capacitive micromachined ultrasonic transducers, where conventional acoustic attenuating members are ineffective in reducing noise for frequencies lower than 2 MHz.

Innovation Solution

The implementation of a configuration with a first and second acoustic matching layer and an acoustic attenuating member on the back surface of the electric wiring substrate, which reduces reflection noise by matching acoustic impedances and absorbing ultrasonic waves, thereby improving the signal-to-noise ratio across a wider frequency band.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the distance between the substrate and electric wiring substrate is reduced for higher density array, then electrical connection is improved, but acoustic reflection noise from the back surface affects the electromechanical transducer elements

Engineering Contradiction:

Improvetransducer element densityVSAvoidacoustic reflection noise

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The second acoustic attenuating member (24) acts as an intermediary element placed on the back surface of the electric wiring substrate. This intermediary structure provides acoustic attenuation without requiring increased spacing between the substrate and electric wiring substrate, thus maintaining high transducer element density while still reducing acoustic reflection noise that would otherwise affect the electromechanical transducer elements.

Inventive Principle:

Principle #24Intermediary (Mediator)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This configuration effectively reduces noise applied to the electromechanical transducer elements, enhancing the signal-to-noise ratio and improving the imaging precision in medical diagnostic applications by attenuating low-frequency ultrasonic waves and minimizing reflection noise.

Implementation Method 1

matching acoustic impedances and absorbing ultrasonic waves

Methodology Applied

Scientific EffectAcoustic impedance matching: Reflection

Implementation Method 2

absorbing ultrasonic waves, thereby improving the signal-to-noise ratio

Methodology Applied

Scientific EffectAcoustic absorption: Acoustic Absorption

Data Source

PatentUS9698705B2Electromechanical transducer device and analyte information acquiring apparatus

Publication Date: 2017.07.04 CANON KK

AI summary

To suggest an electromechanical transducer device with a high S/N ratio, an electromechanical transducer device includes a first substrate; electromechanical transducer elements two-dimensionally arrayed on a front surface of the first substrate and configured to provide conversion between acoustic waves and electric signals; an electric wiring substrate that is a second substrate electrically connected with a back surface of the first substrate; a first acoustic matching layer provided between the first substrate and the second substrate; an acoustic attenuating member arranged on a back surface of the second substrate; and a second acoustic matching layer provided between the second substrate and the acoustic attenuating member.