Offset Ultrasonic Element for Distinct Directivity Modes
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional ultrasonic transducers with two bottomed, cylindrical cases of differing sizes face challenges in distinguishing between short-range objects like wheel stops and tall structures due to similar directivity characteristics at different resonance frequencies, leading to difficulties in accurate object detection.
Innovation Solution
An ultrasonic transducer with a bottomed, cylindrical transducer case and an ultrasonic element offset in the in-plane direction, allowing for the generation of first and second transmission waves with distinct directivity characteristics, where sound pressure is decreased in the axial direction, enabling improved object detection by switching between these modes using a control circuit element.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional ultrasonic transducer with two bottomed cylindrical cases is used, then the device can transmit ultrasonic waves, but the directivity characteristics at different resonance frequencies are similar, making it difficult to distinguish between short-range objects and tall structures
Solution Approach 1:
The patent applies asymmetry by offsetting the ultrasonic element from the center position of the diaphragm in the in-plane direction. This asymmetric arrangement creates distinct directivity characteristics between different resonance modes, enabling the transducer to differentiate between short-range objects (first transmission wave) and tall structures (second transmission wave) that would otherwise be indistinguishable with symmetric conventional designs
2Measurement precision
If the ultrasonic element is positioned at the center of the diaphragm, then the structure is simple and manufacturing is easier, but the directivity characteristics are identical for both transmission waves, reducing object detection accuracy
Solution Approach 1:
The patent deliberately introduces asymmetry by positioning the ultrasonic element offset from the diaphragm center in the in-plane direction. This asymmetric placement generates the desired different directivity characteristics for first and second transmission waves, enabling accurate distinction between short-range and tall-range objects while accepting the moderate increase in manufacturing complexity
3Reliability
If the first transmission wave with strong axial sound pressure is used, then short-range object detection is effective, but tall structures cannot be distinguished, leading to erroneous detections
Solution Approach 1:
The patent applies dynamics by enabling the transducer to switch between different transmission modes (first and second transmission waves) based on the detection requirements. The control circuit dynamically selects which mode to activate: the first mode for short-range object detection or the second mode for distinguishing tall structures, thereby eliminating erroneous detections and improving overall detection reliability
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 enhances object detection performance by differentiating between short-range and tall-range objects, reducing erroneous detections and improving the detection area, while maintaining minimal manufacturing costs and durability.
Implementation Method 1
an ultrasonic element that is fixedly supported to the bottom plate portion so as to face an interior space that is surrounded by the side plate portion and the bottom plate portion, and converts between an electrical signal and ultrasonic vibrations
Implementation Method 2
a bottom plate portion that seals one end side of the side plate portion in an axial direction that is parallel to the center axis so as to configure a diaphragm that is capable of ultrasonic vibration
Data Source
AI summary
An ultrasonic transducer includes a transducer case and an ultrasonic element. The transducer case is formed into a bottomed, cylindrical shape having a side plate portion and a bottom plate portion that seals one end side of the side plate portion in an axial direction to configure a diaphragm. The ultrasonic element is fixedly supported to the bottom plate portion to face an interior space surrounded by the side plate portion and the bottom plate portion. The ultrasonic element is arranged in a position being offset in an in-plane direction orthogonal to the axial direction relative to a center position of the diaphragm in the in-plane direction to be capable of generating a first transmission wave having first directivity characteristics and a second transmission wave having second directivity characteristics that are directivity characteristics differing from the first directivity characteristics and in which sound pressure in the axial direction is decreased.