Ultrasonic Sensor Vibration Plate Segmentation for Reception Accuracy
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Solution Overview
Problem
Ultrasonic devices with high Q values in diaphragm-type ultrasonic sensors suffer from reduced reception sensitivity due to excess vibration, making it difficult to distinguish signal from noise and reverberant vibrations, and the addition of elastic layers to absorb excess vibration compromises reception sensitivity.
Innovation Solution
An ultrasonic device with a substrate, a vibration plate, piezoelectric elements, and an elastic layer with a curved surface recessed towards the vibration plate, where the elastic layer's thickness is between 20 μm and 40 μm and curvature is within 10,000 to 20,000, functioning as a damper to absorb excess vibration and improve reception accuracy while maintaining sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the Q value of the vibration plate is set high to improve ultrasound transmission efficiency, then transmission efficiency is improved, but reception accuracy deteriorates due to excess vibration and noise
Solution Approach 1:
The invention divides the vibration plate into functionally distinct regions: a first vibration region for ultrasound transmission with high Q value, and a second vibration region for ultrasound reception with low Q value. This segmentation allows each region to be optimized for its specific function, resolving the contradiction between transmission efficiency and reception accuracy.
Solution Approach 2:
The invention applies different quality factors (Q values) to different spatial locations of the vibration plate. The first vibration region maintains high Q for efficient transmission, while the second vibration region has low Q to suppress reverberation and improve reception accuracy. This local differentiation of properties resolves the contradiction.
2Measurement precision
If an elastic layer is provided to absorb excess vibration and improve reception accuracy, then reception accuracy is improved, but reception sensitivity deteriorates due to decreased displacement amount
Solution Approach 1:
The invention segments the vibration plate into regions with different Q values, allowing the second vibration region to naturally suppress excess vibration through its low Q value without requiring an elastic layer. This maintains the displacement amount and reception sensitivity while still improving reception accuracy.
Solution Approach 2:
The invention replaces the mechanical damping approach (using an elastic layer to absorb vibration) with a structural approach (designing the vibration plate with regions of different Q values). This substitution maintains vibration amplitude while achieving vibration suppression, thereby preserving reception sensitivity.
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 configuration enhances reception accuracy by reducing noise and reverberation time while maintaining or improving reception sensitivity by refracting ultrasound effectively onto the vibration region, effectively functioning as an acoustic lens.
Implementation Method 1
piezoelectric elements provided in vibration regions corresponding to the opening sections in the vibration plate. The ultrasonic device described in Patent Literature 1 applies a voltage to the piezoelectric elements to vibrate the vibration regions
Implementation Method 2
The elastic layer includes a curved surface recessed to the vibration plate side... effectively functioning as an acoustic lens
Implementation Method 3
the elastic layer... functioning as a damper to absorb excess vibration and improve reception accuracy
Data Source
AI summary
An ultrasonic device according to an aspect of the present disclosure includes a substrate in which an opening section piercing through the substrate in a thickness direction is provided, a vibration plate provided on the substrate to close the opening section, a piezoelectric element provided in a position corresponding to the opening section on a first surface at the opposite side of the substrate side of the vibration plate, and an elastic layer provided in contact with a second surface at the substrate side of the vibration plate at the inner side of the opening section of the substrate. The elastic layer includes a curved surface recessed to the vibration plate side at the opposite side of the vibration plate side.