Capacitive type humidity sensor
First Claim
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1. A capacitive type humidity sensor comprising:
- a semiconductor substrate;
a plurality of humidity devices having a capacitance variable in accordance with a humidity;
a plurality of standard capacitance devices having a standard capacitance, a capacitance change of which in accordance with the humidity is smaller than that of the capacitance of each humidity device;
a CV converter circuit for converting a capacitance difference between the capacitance of each humidity device and the standard capacitance of a corresponding one of the plurality of standard capacitance devices to a signal voltage; and
a casing configured to receive the semiconductor substrate, the plurality of humidity devices, the plurality of standard capacitance devices, and the CV control circuit, whereinthe plurality of humidity devices, the plurality of standard capacitance devices and the CV converter circuit are disposed on one side of the substrate in a direction perpendicular to a plane of the substrate;
the casing includes at least one separation wall, which is placed on the one side of the substrate to partition an interior of the casing into a plurality of chambers;
each humidity device and the corresponding one of the plurality of standard capacitance devices are received in a corresponding one of the plurality of chambers; and
the plurality of humidity devices and the plurality of standard capacitance devices are configured to be operated to simultaneously measure the humidity of gas introduced into each of the plurality of chambers.
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Abstract
A capacitive type humidity sensor includes: a semiconductor substrate; a plurality of humidity devices having a capacitance variable in accordance with a humidity; a standard capacitance device having a standard capacitance, a capacitance change of which in accordance with the humidity is smaller than that of the capacitance of each humidity device; and a CV converter circuit for converting a capacitance difference between the capacitance of each humidity device and the standard capacitance of the standard capacitance device to a signal voltage. The humidity devices, the standard capacitance device and the CV converter circuit are disposed on one side of the substrate.
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Citations
11 Claims
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1. A capacitive type humidity sensor comprising:
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a semiconductor substrate; a plurality of humidity devices having a capacitance variable in accordance with a humidity; a plurality of standard capacitance devices having a standard capacitance, a capacitance change of which in accordance with the humidity is smaller than that of the capacitance of each humidity device; a CV converter circuit for converting a capacitance difference between the capacitance of each humidity device and the standard capacitance of a corresponding one of the plurality of standard capacitance devices to a signal voltage; and a casing configured to receive the semiconductor substrate, the plurality of humidity devices, the plurality of standard capacitance devices, and the CV control circuit, wherein the plurality of humidity devices, the plurality of standard capacitance devices and the CV converter circuit are disposed on one side of the substrate in a direction perpendicular to a plane of the substrate; the casing includes at least one separation wall, which is placed on the one side of the substrate to partition an interior of the casing into a plurality of chambers; each humidity device and the corresponding one of the plurality of standard capacitance devices are received in a corresponding one of the plurality of chambers; and the plurality of humidity devices and the plurality of standard capacitance devices are configured to be operated to simultaneously measure the humidity of gas introduced into each of the plurality of chambers. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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Specification