Ultrasonic Sensor Array with Ferroelectret Membrane for Precise Detection
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Solution Overview
Problem
Existing ultrasonic sensors for environment detection, particularly in motor vehicle applications, face challenges in accurately detecting multiple objects in complex environments due to limitations in precision and cost-effectiveness.
Innovation Solution
A sound wave-based sensor system comprising at least two sound transducers positioned less than half the wavelength apart, utilizing ferroelectret materials for the sound-generating membrane, with a common electrode configuration for cost-effective production and flexible electrode structures, enabling precise direction and distance detection of surrounding objects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If individual sound transducers are used for environment detection, then the sensor system can detect objects in the environment, but the precision of detecting direction and distance of multiple objects is insufficient
Solution Approach 1:
The patent combines multiple sound transducers (at least two) into a single sensor unit with a common membrane, creating an array arrangement that enables precise detection of direction and distance of multiple objects while maintaining a compact structure. The transducers are positioned at a distance of less than half the wavelength from each other, allowing them to function as an integrated detection system rather than separate sensors.
Solution Approach 2:
The sensor divides the detection function into multiple sound transducers within a single unit, where each transducer contributes to the overall detection capability. This segmentation allows the system to determine direction and distance of multiple objects by processing signals from individual transducers, thereby improving measurement precision without requiring completely separate sensor systems.
2Reliability
If conventional sound transducer materials are used, then the transducer can generate sound waves, but the robustness and cost-effectiveness are insufficient
Solution Approach 1:
The patent changes the material parameter of the sound-generating membrane from conventional materials to ferroelectret material, which provides superior robustness and durability. This material parameter change enhances the reliability of the transducer while the common electrode configuration and film structure maintain cost-effective production through simplified manufacturing processes.
Solution Approach 2:
The patent employs ferroelectret material, which is a composite material with unique properties combining piezoelectric and electrostatic characteristics. This composite material enables the membrane to generate sound waves effectively while providing enhanced robustness. The combination of ferroelectret material with vapor-deposited metallization creates a durable yet cost-effective transducer structure.
3Measurement precision
If multiple sound transducers are positioned far apart, then each transducer can operate independently, but the detection precision of direction and distance is reduced
Solution Approach 1:
The patent optimizes the spatial parameter by positioning sound transducers at a specific distance of less than half the wavelength from each other. This parameter optimization enables the transducers to function as an integrated array for precise direction and distance detection, while maintaining a compact overall size. The specific spacing creates constructive interference patterns that enhance detection precision.
4Manufacturing precision
If complex electrode structures are used in the membrane, then the sound wave generation can be optimized, but the manufacturing complexity and cost increase
Solution Approach 1:
The patent merges the electrode structures by providing a common electrode configuration where at least two sound transducers share common electrodes. This merging simplifies the manufacturing process and reduces production complexity while maintaining optimized sound wave generation. The common electrode structure allows for easier fabrication compared to completely separate electrode systems for each transducer.
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 sensor system achieves precise detection of multiple objects in complex environments, is cost-effective, and suitable for various applications including motor vehicle surroundings, robot navigation, and industrial surveillance, with enhanced robustness and flexibility.
Implementation Method 1
the sound-generating membrane of at least one of the sound transducers is made from a ferroelectret material or at least has this material
Implementation Method 2
sound above the audio frequency range is emitted into the environment by a sound transducer
Implementation Method 3
reflected by corresponding objects in the environment and registered by suitable sound receivers
Data Source
Figure 1a~1b
Figure 1c~1d
Figure 2a~2d
AI summary
The invention relates to a sound wave based sensor (10) for detecting surroundings, particularly an ultrasonic sensor for motor vehicle applications, comprising an array of at least two sound transducers (20a, 20b) for generating and/or detecting sound waves, wherein the sound transducers (20a, 20b) are positioned at a distance from each other of less than half the wavelength of the generated and/or detected sound waves.