Pressing sensor and electronic device
First Claim
1. A pressing sensor comprising:
- a piezoelectric sensor configured to generate a detection voltage corresponding to a deformation amount of a pressing surface;
a first current-voltage conversion circuit configured to convert a charge/discharge current for a capacitance of the piezoelectric sensor into a voltage signal;
a second current-voltage conversion circuit configured to current-voltage convert a current corresponding to a change rate of an output voltage of the first current-voltage conversion circuit;
a deformation amount detector configured to obtain an integrated value of an output voltage from the second current-voltage conversion circuit and determine the integrated value as the deformation amount of the pressing surface;
a minute vibration sensor configured to detect presence or absence of minute vibration of the pressing surface based on a minute fluctuation state of the output voltage; and
an integration reset processor configured to reset the integrated value obtained by the deformation amount detector when the minute vibration sensor detects an absence of the minute vibration.
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Accused Products
Abstract
A pressing sensor that includes a pressing portion deformed by pressing, a piezoelectric sensor that generates a detection voltage based on the deformation amount, and a first current-voltage conversion circuit that converts a charge/discharge current for a capacitance of the piezoelectric sensor into a voltage signal and outputs the voltage signal. Moreover, a deformation amount detector obtains an integrated value of an output voltage and detects the integrated value as the deformation amount of the pressing portion. A minute vibration sensor detects presence or absence of minute vibration of the pressing portion according to presence or absence of a minute fluctuation state of the output voltage and an integration reset processor resets the integrated value in response to absence of the minute vibration.
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Citations
16 Claims
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1. A pressing sensor comprising:
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a piezoelectric sensor configured to generate a detection voltage corresponding to a deformation amount of a pressing surface; a first current-voltage conversion circuit configured to convert a charge/discharge current for a capacitance of the piezoelectric sensor into a voltage signal; a second current-voltage conversion circuit configured to current-voltage convert a current corresponding to a change rate of an output voltage of the first current-voltage conversion circuit; a deformation amount detector configured to obtain an integrated value of an output voltage from the second current-voltage conversion circuit and determine the integrated value as the deformation amount of the pressing surface; a minute vibration sensor configured to detect presence or absence of minute vibration of the pressing surface based on a minute fluctuation state of the output voltage; and an integration reset processor configured to reset the integrated value obtained by the deformation amount detector when the minute vibration sensor detects an absence of the minute vibration. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A pressing sensor comprising:
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a pressing surface deformable by a pressing force; a pressure sensor configured to generate a detection signal corresponding to a deformation amount of the pressing surface; a first current-voltage conversion circuit that includes an operational amplifier with an inverting input coupled to the pressure sensor and a non-inverting input coupled to a reference potential generating circuit; a second current-voltage conversion circuit configured to current-voltage convert a current corresponding to a change rate of an output voltage of the first current-voltage conversion circuit, the second current-voltage conversion circuit including an operational amplifier with an inverting input configured to receive the current corresponding to the change rate of the output voltage and a non-inverting input coupled to the reference potential generating circuit; a deformation amount detector configured to detect the deformation amount based on an output voltage from the second current-voltage conversion circuit; and a minute vibration sensor configured to detect a presence or an absence of minute vibration of the pressing surface based on a presence or an absence of a minute fluctuation state of the detection signal generated by the pressure sensor. - View Dependent Claims (13, 14, 15, 16)
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Specification