Integrated Electret Ferroelectret Transducer Design
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Solution Overview
Problem
Existing transducers have unused areas and surfaces that do not contribute to the electret or piezo effect, leading to non-optimal sensitivity and signal quality due to the separation of electret and piezo effects in their design.
Innovation Solution
A transducer design that combines electret and ferroelectret effects by electrically connecting them in series or parallel, with the electret and ferroelectret being conductively connected to different electrodes, allowing for enhanced sensitivity and signal amplification by utilizing the available volume and area effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If electret and piezo elements are used separately in conventional transducers, then the structure is simple and manufacturing is easier, but the sensitivity and signal-to-noise ratio are suboptimal due to unused areas and surfaces
Solution Approach 1:
The patent combines electret and piezo elements into a single integrated transducer structure where both elements share common electrodes and operate simultaneously. The electret element and piezo element are positioned adjacent to each other with shared first and second electrodes, allowing both electret and piezo effects to contribute to the output signal from the same acoustic input, thereby improving sensitivity without requiring separate transducer structures.
Solution Approach 2:
The transducer structure serves multiple functions simultaneously: the first electrode serves as both an electret electrode and a piezo electrode, the second electrode serves as both an electret counter-electrode and a piezo counter-electrode, and the air gap serves as both the electret spacing and part of the piezo structure. This multi-functionality allows the same structural elements to contribute to both electret and piezo effects.
2Reliability
If electret and piezo elements are combined in one transducer, then the sensitivity and signal-to-noise ratio are improved, but the device complexity increases
Solution Approach 1:
The patent combines electret and piezo elements into a single integrated transducer structure where both elements share common electrodes and operate simultaneously. The electret element and piezo element are positioned adjacent to each other with shared first and second electrodes, allowing both electret and piezo effects to contribute to the output signal from the same acoustic input, thereby improving sensitivity without requiring separate transducer structures.
Solution Approach 2:
The patent implements fail-safety by having redundant signal paths through both electret and piezo elements. If one element fails or discharges (as mentioned in the background for electrets), the other element continues to provide a meaningful signal, ensuring continuous transducer functionality. This redundancy is built into the structure from the beginning.
3Productivity
If conventional separate electret or piezo transducers are used, then the manufacturing process is simpler, but the available volume and area are not fully utilized leading to non-optimal sensitivity
Solution Approach 1:
The patent combines electret and piezo elements into a single integrated transducer structure where both elements share common electrodes and operate simultaneously. The electret element and piezo element are positioned adjacent to each other with shared first and second electrodes, allowing both electret and piezo effects to contribute to the output signal from the same acoustic input, thereby improving sensitivity without requiring separate transducer structures.
Solution Approach 2:
The patent utilizes parameter changes in the dielectric properties of the electret material and the piezoelectric properties of the piezo element to enable both effects to operate within the same structural framework. By selecting materials with appropriate electret charge stability and piezoelectric coefficients, the transducer optimizes signal output while maintaining a unified structure.
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 combination of electret and ferroelectret effects increases the sensitivity and signal-to-noise ratio of the transducer, provides fail-safety by allowing continued functionality even if one element fails, and optimizes the use of available space for improved performance.
Implementation Method 1
the electret and the ferroelectret are conductively connected to the electrode of the second type (3). The electret effect and the piezo effect are combined in one converter
Implementation Method 2
The ferroelectrets are piezoelectric and exhibit piezo constants comparable to lead zirconate titanate (PZT) piezoelectrics
Data Source
AI summary
The invention relates to a transducer (1) having at least one electrode of a first type (2), at least one electrode of a second type (3) and at least one ferroelectret (6). The transducer (1) additionally has at least one electret (4), wherein the electrode of the first type (2) is conductively connected to the ferroelectret (6), the electret (4) is spaced apart from the electrode of the first type (2) by at least one air gap (5) and the electret (4) and the ferroelectret (6) are conductively connected to the electrode of the second type (3). The invention further relates to an ultrasonic sensor and a microphone which have such a transducer (1).