Piezoelectric Sensor With Memristor Half-Bridge for DC Force Measurement
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Solution Overview
Problem
Piezoelectric transducers are not suitable for measuring constant forces over time due to their inability to detect DC signals and require extensive active circuitry, which is space-intensive and prone to interference from poor insulation resistance and electromagnetic interference.
Innovation Solution
A sensor element combining a piezoelectric converter with a memristor in a half-bridge configuration, allowing for low-impedance connection to readout electronics and operation using alternating voltage, enabling reliable signal recording and reducing the area requirement for circuitry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a piezoelectric transducer is used to measure force, then measurement capability is provided, but the transducer cannot measure DC signals and requires extensive active circuitry
Solution Approach 1:
The patent replaces complex active electronic circuitry (charge amplifiers, impedance converters) with a passive memristor-based half-bridge circuit. The memristor's non-linear impedance characteristics enable signal amplification and DC measurement capability without requiring active electronic components, thereby reducing circuit complexity while maintaining measurement reliability
Solution Approach 2:
The patent utilizes the memristor's ability to change its resistance based on accumulated charge (memory effect). By operating the piezoelectric transducer in a half-bridge configuration with memristors, the system can measure DC signals and slowly varying forces by detecting changes in the memristor's resistance state, which retains information about the integrated charge over time
2Reliability
If an active circuit (charge amplifier) is used to enable DC measurement, then DC measurement capability is achieved, but the area requirement increases
Solution Approach 1:
The patent substitutes bulky active electronic components with compact passive memristor devices. The memristor-based half-bridge circuit achieves DC measurement capability with significantly reduced footprint compared to traditional charge amplifiers, as memristors can be fabricated using standard semiconductor processes in compact integrated structures
Solution Approach 2:
The memristor serves multiple functions simultaneously: it acts as an impedance matching element, a signal amplification component, and a memory element for integrating charge over time. This multi-functionality eliminates the need for separate active circuit components, thereby reducing the overall circuit area while maintaining DC measurement capability
3Reliability
If poor insulation resistance is present, then measurement is affected by interference, but insulation resistance cannot be easily improved
Solution Approach 1:
The patent replaces sensitive active electronic amplification circuits with a passive memristor-based measurement system. The memristor's non-linear impedance characteristics and memory effect provide inherent immunity to electromagnetic interference and poor insulation conditions, as the measurement is based on charge integration rather than voltage amplification, thereby improving measurement accuracy without requiring improved insulation
Solution Approach 2:
The patent converts the piezoelectric transducer's natural charge output, which is typically too small for direct measurement, into a measurable signal by using the memristor's non-linear I-V characteristics. The memristor's resistance changes in response to the small charge signals, providing signal amplification that is inherently insensitive to electromagnetic interference and insulation issues, thereby turning a weakness into a strength
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
Enables reliable detection of transient signals with reduced area requirements, low-impedance readout, and robust signal transmission, minimizing electromagnetic interference and allowing for high-resolution measurements in force, pressure, or acceleration sensors.
Implementation Method 1
The piezoelectric effect is known per se and is used technically to measure an applied force. The force leads to an elastic deformation of a beam or a membrane and thus to a change in the electrical polarization in the material.
Implementation Method 2
A memristor (portmanteau word: memory and resistor) within the meaning of the present invention is a passive component whose electrical resistance is not constant but depends on its past. The resistance of the memristor, also known as the memristance, M(t), depends on the integral of the current that has flowed through it in the past
Data Source
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AI summary
The invention relates to a sensor element (10) having at least one piezoelectric transducer (11), said piezoelectric transducer (11) being coupled to at least one memristor (20). The invention further relates to a sensor having an array of a plurality of pixels, at least one of the pixels comprising a sensor element (10).