Method and system for measuring physical parameters with a piezoelectric bimorph cantilever in a gaseous or liquid environment
First Claim
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1. A method for measuring at least two physical parameters in an environment comprising at least one of a gas and a liquid, the method comprising:
- providing a piezoelectric bimorph cantilever comprising at least a first layer, a piezoelectric layer, and two electrodes;
placing the piezoelectric bimorph cantilever in the environment;
vibrating the piezoelectric bimorph cantilever, wherein vibrating the piezoelectric bimorph cantilever comprises applying an AC voltage across the two electrodes;
determining the resonant frequencies of at least two resonance modes of the piezoelectric bimorph cantilever, wherein applying the AC voltage across the two electrodes and determining the resonant frequency of the at least two resonance modes of the piezoelectric bimorph cantilever is achieved with an impedance analyzer; and
determining at least two physical parameters of the environment, each based on a combination of resonant frequencies of the at least two resonance modes.
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Abstract
A piezoelectric bimorph cantilever is used for determining physical parameters in a gaseous or liquid environment. The sensor works as a driven and damped oscillator. Contrary to common cantilever sensor systems, the piezoelectric film of the bimorph cantilever acts as both a sensor and an actuator. Using at least two resonance mode of the bimorph cantilever, at least two physical parameters can be measured simultaneously in a gas or a liquid. An optimized piezoelectric cantilever and a method to produce the cantilever are also described.
20 Citations
14 Claims
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1. A method for measuring at least two physical parameters in an environment comprising at least one of a gas and a liquid, the method comprising:
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providing a piezoelectric bimorph cantilever comprising at least a first layer, a piezoelectric layer, and two electrodes; placing the piezoelectric bimorph cantilever in the environment; vibrating the piezoelectric bimorph cantilever, wherein vibrating the piezoelectric bimorph cantilever comprises applying an AC voltage across the two electrodes; determining the resonant frequencies of at least two resonance modes of the piezoelectric bimorph cantilever, wherein applying the AC voltage across the two electrodes and determining the resonant frequency of the at least two resonance modes of the piezoelectric bimorph cantilever is achieved with an impedance analyzer; and determining at least two physical parameters of the environment, each based on a combination of resonant frequencies of the at least two resonance modes. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method for measuring at least two physical parameters in an environment comprising at least one of a gas and a liquid, the method comprising:
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providing a piezoelectric bimorph cantilever comprising at least a first layer, a piezoelectric layer, and two electrodes; placing the piezoelectric bimorph cantilever in the environment; vibrating the piezoelectric bimorph cantilever; determining the resonant frequencies of at least two resonance modes of the piezoelectric bimorph cantilever, wherein determining the resonant frequencies of the at least two resonance modes of the piezoelectric bimorph cantilever comprises using a frequency-selective network; and determining at least two physical parameters of the environment, each based on a combination of resonant frequencies of the at least two resonance modes. - View Dependent Claims (12)
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13. A method for measuring at least two physical parameters in an environment comprising at least one of a gas and a liquid, the method comprising:
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providing a piezoelectric bimorph cantilever comprising at least a first layer, a piezoelectric layer, and two electrodes; placing the piezoelectric bimorph cantilever in the environment; vibrating the piezoelectric bimorph cantilever; determining the resonant frequencies of at least two resonance modes of the piezoelectric bimorph cantilever, wherein determining the at least two physical parameters of the environment based on the at least two resonance modes comprises comparing the at least two resonance modes with calibration curves; and determining at least two physical parameters of the environment, each based on a combination of resonant frequencies of the at least two resonance modes. - View Dependent Claims (14)
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Specification