Piezoelectric Pressure Sensor Capacitance Force Measurement
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Solution Overview
Problem
Existing force measurement systems using piezoelectric sensors require a charging amplifier, limiting miniaturization and increasing complexity.
Innovation Solution
The method utilizes the change in capacitance of a piezoelectric pressure sensor to measure force, eliminating the need for a charge amplifier and allowing for a miniaturized measuring system by using hard or soft piezoelectric materials, which can be polarized or unpolarized, and employing a lock-in process at a specific frequency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a charge amplifier is used for force measurement with piezoelectric sensors, then measurement accuracy is maintained, but device complexity increases and miniaturization is limited
Solution Approach 1:
The patent extracts and eliminates the charge amplifier component from the measuring system by transitioning to a capacitive measurement method. The force measurement is performed by detecting capacitance changes of the piezoelectric sensor itself, removing the need for external charge amplification circuitry and thereby reducing device complexity while maintaining measurement capability
Solution Approach 2:
The patent replaces the electrical charge amplification system with a direct capacitive sensing approach. Instead of measuring induced charge through amplifiers, the system measures capacitance changes directly, substituting a simpler electrical measurement method for the more complex charge amplification process
2Reliability
If a charge amplifier is used for force measurement, then reliable force detection is achieved, but the measuring system size increases
Solution Approach 1:
The charge amplifier is extracted and removed from the measuring system. The patent achieves reliable force detection without this component by using the piezoelectric sensor's inherent capacitance changes as the measurement signal, thereby reducing the overall system volume
Solution Approach 2:
The piezoelectric sensor serves multiple functions: it acts as both the force-sensing element and the capacitive measurement element. This multi-functionality eliminates the need for separate charge amplification circuitry, reducing system volume while maintaining 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
This approach enables a compact and efficient force measurement system without the need for a charge amplifier, offering simpler force detection and more precise measurements, suitable for various applications including medical and industrial uses.
Implementation Method 1
the force is determined by means of the induced charge, as is the case for example in quartz load cells and piezoelectric sensors
Implementation Method 2
the change in the capacitance of the pressure sensor is used for force measurement
Data Source
AI summary
A method, a device and use for measurement of a force with a pressure sensor made of a piezoelectric material. The change in the capacitance of the pressure sensor is used for force measurement so that no load amplifier is necessary for measurement and as a result the measuring system as a whole is miniaturized.