Ultrasonic Diaphragm Deflection Control via Piezoelectric Voltage
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Solution Overview
Problem
Conventional diaphragm-type ultrasonic sensors face challenges in controlling stress-induced deflection, which results in unstable properties and difficulty in optimizing transmission and reception characteristics due to variations in diaphragm film formation conditions and temperature changes.
Innovation Solution
The ultrasonic device employs a substrate with a diaphragm and a piezoelectric member comprising a first and second piezoelectric part, where the control unit applies specific voltages to control the deflection of the diaphragm, allowing for uniform and stable properties and optimized transmission and reception capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If the diaphragm is deflected using internal stress from multi-layered film formation, then the diaphragm becomes convex and ultrasonic transmission is enabled, but the stress for deflecting the diaphragm is difficult to control and properties vary from sensor to sensor
Solution Approach 1:
The patent replaces the mechanical stress-based deflection control (using internal stress from multi-layered film formation) with an electrical control system. A piezoelectric element is integrated into the diaphragm structure, allowing precise control of diaphragm deflection through applied voltage. This substitution enables accurate and repeatable deflection control while eliminating the variability associated with film formation conditions.
Solution Approach 2:
The patent changes the control parameter from mechanical stress (which varies with film formation conditions) to electrical voltage (which can be precisely controlled). By applying different voltages to the piezoelectric element, the diaphragm deflection can be accurately adjusted to achieve optimal ultrasonic transmission properties, eliminating the difficulty of controlling deflection through mechanical means.
2Shape
If the diaphragm is deflected using internal stress, then the diaphragm shape is changed, but the level of diaphragm deflection varies as the diaphragm temperature varies, resulting in unstable properties
Solution Approach 1:
The patent replaces temperature-sensitive mechanical stress-based deflection with an electrically-controlled piezoelectric system. The piezoelectric element responds to voltage changes rather than temperature changes, providing stable and predictable deflection control. This substitution eliminates the instability caused by temperature variations in the diaphragm's mechanical properties.
3Shape
If the diaphragm shape changes after sensor formation, then ultrasonic transmission may be affected, but transmission and reception properties are difficult to optimize because of changes in the shape of the diaphragm
Solution Approach 1:
The patent incorporates the piezoelectric element and control system into the diaphragm structure during the manufacturing process, enabling preliminary adjustment of the diaphragm shape to the optimal configuration. This allows the diaphragm to be pre-deflected to the ideal shape for ultrasonic transmission before the sensor is finalized, making it easier to manufacture sensors with optimized transmission and reception properties.
Solution Approach 2:
The patent uses electrical voltage as a controllable parameter to adjust the diaphragm shape after formation. By applying appropriate voltages to the piezoelectric element, the diaphragm can be deflected to achieve optimal ultrasonic transmission and reception properties, making the optimization process straightforward and repeatable during manufacturing.
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 enables precise control over the deflection and stress distribution of the diaphragm, leading to stable and uniform ultrasonic device properties, improved productivity, and reduced manufacturing costs.
Implementation Method 1
The piezoelectric member is coupled to the diaphragm, and includes a first piezoelectric part and a second piezoelectric part. The control unit controls a voltage applied to the first piezoelectric part to be a vibration voltage and controls a voltage applied to the second piezoelectric part to be a constant voltage when the ultrasonic device transmits the ultrasonic waves.
Implementation Method 2
The control unit detects a voltage produced by the first piezoelectric part to be output as an output signal and controls a voltage applied to the second piezoelectric part to be a constant voltage when the ultrasonic device receives the ultrasonic waves.
Data Source
AI summary
An ultrasonic device is configured to transmit ultrasonic waves and includes a substrate, a diaphragm, a piezoelectric member and a control unit. The substrate has an opening. The diaphragm covers the opening of the substrate. The piezoelectric member is coupled to the diaphragm, and includes a first piezoelectric part and a second piezoelectric part. The control unit controls a voltage applied to the first piezoelectric part to be a vibration voltage and controls a voltage applied to the second piezoelectric part to be a constant voltage when the ultrasonic device transmits the ultrasonic waves.