Ultrasonic Device Acoustic Matching Layer Thickness Control
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Solution Overview
Problem
Existing ultrasonic devices face issues with air bubbles entering the device when in contact with objects, leading to impaired ultrasonic wave transmission, and existing acoustic matching solutions cause wavelength unevenness across different frequencies.
Innovation Solution
An ultrasonic device with a vibration plate, a piezoelectric element, prevention portions, and an acoustic matching layer on the vibration plate's surface, where the thickness of the acoustic matching layer is set such that t≤V/f, preventing air bubbles and ensuring consistent ultrasonic wave transmission across a wide frequency range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the opening is filled with an acoustic matching portion to prevent air bubbles from entering, then air bubble prevention is improved, but wavelength unevenness for each frequency occurs in ultrasonic wave transmittance
Solution Approach 1:
The patent changes the physical parameter of the acoustic matching layer by controlling its thickness to be less than one wavelength of the ultrasonic wave. This parameter change allows the layer to prevent air bubbles while minimizing wavelength-dependent transmittance variations, resolving the contradiction between reliability and manufacturing precision.
Solution Approach 2:
Instead of filling the opening completely with acoustic matching material (excessive action), the patent applies a thin layer (partial action) with controlled thickness. This partial application prevents air bubbles from entering while avoiding the wavelength unevenness that occurs with thicker layers.
2Reliability
If a thick acoustic matching layer is used to prevent air bubbles, then air bubble prevention is improved, but transmittance of ultrasonic waves becomes uneven across different frequencies
Solution Approach 1:
The patent optimizes the thickness parameter of the acoustic matching layer to be less than one wavelength. This parameter optimization maintains air bubble prevention across a wide frequency range while avoiding the wavelength unevenness that would limit frequency adaptability.
3Adaptability or versatility
If the opening is left open to maintain wide frequency bandwidth, then frequency range is improved, but air bubbles enter and impair ultrasonic wave transmission
Solution Approach 1:
The patent introduces an acoustic matching layer as an intermediary substance between the opening and the external environment. This layer mediates by preventing air bubbles from entering while maintaining the open structure needed for wide frequency bandwidth, thus preserving both reliability and adaptability.
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
The solution prevents damage to the vibration plate, reduces air bubble formation, and maintains consistent ultrasonic wave transmission efficiency across a wide frequency range, enhancing the device's ability to transmit waves effectively to objects like living bodies.
Implementation Method 1
a piezoelectric element stacked on an opposite side of the vibration plate from the opening
Implementation Method 2
an acoustic matching layer that is provided on the first surface and is brought into contact with an object
Implementation Method 3
a prevention portion that is disposed on the second surface in a manner of surrounding the piezoelectric element, and prevents vibration of the vibration plate
Data Source
AI summary
An ultrasonic device includes a vibration plate having a first surface and a second surface opposite to the first surface, an acoustic matching layer that is provided on the first surface and is brought into contact with an object, a piezoelectric element provided on the second surface, and a prevention portion that is disposed in a manner of surrounding the piezoelectric element, and prevents vibration of the vibration plate. When a thickness of the acoustic matching layer is defined as t, a sound velocity of ultrasonic waves is defined as V, and a center frequency of ultrasonic waves transmitted from the first surface is defined as f, t≤V/f is satisfied.