Ultrasonic Wave Sensor Segmented Oscillating Plate Design
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Solution Overview
Problem
Ultrasonic wave sensors face degradation in drive characteristics due to increased electrical capacitance when the number of ultrasonic wave transducers is increased to enhance sound pressure, leading to inefficient transmission.
Innovation Solution
The ultrasonic wave sensor employs a configuration with a first area where piezoelectric elements are driven for signal input and output, and a second area that resonates through mechanical crosstalk, reducing the number of driven elements and maintaining high sound pressure transmission while suppressing resonance degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the number of ultrasonic wave transducers (elements) in one channel is increased to increase sound pressure, then transmission sound pressure is improved, but drive characteristics are degraded due to increased total electrical capacitance
Solution Approach 1:
The oscillating plate is divided into a first area with piezoelectric elements that are electrically connected and driven by drive signals, and a second area with piezoelectric elements that are electrically insulated and not directly driven. This segmentation allows only the first area elements to contribute to total capacitance while both areas contribute to sound pressure transmission through mechanical coupling.
Solution Approach 2:
The first area and second area are mechanically combined through the oscillating plate structure, allowing mechanical vibrations from the driven piezoelectric elements in the first area to transmit to the undriven piezoelectric elements in the second area. This merging enables undriven elements to contribute to sound pressure without adding to electrical capacitance burden.
2Power
If the number of piezoelectric elements is increased to enhance ultrasonic wave transmission, then sound pressure is improved, but the total electrical capacitance increases causing drive characteristic degradation
Solution Approach 1:
The oscillating plate is divided into a first area with piezoelectric elements that are electrically connected and driven by drive signals, and a second area with piezoelectric elements that are electrically insulated and not directly driven. This segmentation allows only the first area elements to contribute to total capacitance while both areas contribute to sound pressure transmission through mechanical coupling.
Solution Approach 2:
The oscillating plate acts as a mechanical intermediary that transmits vibrations from the driven piezoelectric elements in the first area to the undriven piezoelectric elements in the second area. This mechanical mediation allows energy transfer without electrical connection, avoiding additional capacitance while achieving enhanced transmission.
3Power
If more piezoelectric elements are electrically connected to drive the ultrasonic wave sensor, then the transmitted ultrasonic wave sound pressure increases, but the drive characteristics deteriorate due to increased total capacitance
Solution Approach 1:
The oscillating plate is divided into a first area with piezoelectric elements that are electrically connected and driven by drive signals, and a second area with piezoelectric elements that are electrically insulated and not directly driven. This segmentation allows only the first area elements to contribute to total capacitance while both areas contribute to sound pressure transmission through mechanical coupling.
Solution Approach 2:
The driven piezoelectric elements in the first area generate mechanical vibrations that propagate through the oscillating plate to the undriven piezoelectric elements in the second area, causing them to vibrate mechanically without electrical drive. This mechanical vibration approach allows additional elements to contribute to sound pressure without increasing electrical drive complexity.
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 allows for high sound pressure ultrasonic wave transmission with improved drive characteristics by reducing the number of driven elements and controlling resonance, thus enhancing the ultrasonic wave sensor's performance.
Implementation Method 1
a piezoelectric element provided on each of the plurality of oscillators... when the piezoelectric element in the first area is driven, the oscillators in both the first area and the second area oscillate
Implementation Method 2
the oscillator in the second area resonates due to the propagation of the mechanical crosstalk to each oscillator disposed in the second area through the oscillating plate
Implementation Method 3
the oscillator in the second area resonates due to the propagation of the mechanical crosstalk
Data Source
AI summary
An ultrasonic wave sensor includes an oscillating plate including a plurality of oscillators, a wall portion provided on the oscillating plate and surrounding the oscillator, and a piezoelectric element provided on each of the plurality of oscillators. In the oscillating plate, a plurality of piezoelectric elements are electrically connected in plan view as viewed from a thickness direction, and a first area where an input and an output of a drive signal to the piezoelectric element are possible and a second area which is provided on an outer side of the first area and where the piezoelectric element is electrically insulated from the piezoelectric element disposed in the first area are included. In the second area, a distance between the adjacent oscillators is reduced as separated from the first area.