| 摘要 |
According to the present invention, there is provided a high-precision differential pressure sensor which is not affected by a considerable change in baseline pressure. A differential pressure sensor of the present invention comprises: a pair of diaphragms, each including a diaphragm portion capable of being deformed due to application of a pressure and a support portion for holding an outer peripheral edge of the diaphragm portion; a pair of fixed electrodes in disk-like form fixed to the support portions of the diaphragms; and a movable electrode including a disk-like electrode portion and shaft-like projections extending in opposite directions from a central portion of the electrode portion. The shaft-like projections extend at a right angle relative to the electrode portion, and the movable electrode is secured to central portions of the diaphragms through the shaft-like projections so that the electrode portion faces each of the fixed electrodes in a predetermined spaced relationship. The movable electrode is capable of moving so as to allow a distance between the electrode portion and each of the fixed electrodes to vary according to a difference between fluid pressures acting on the respective diaphragm portions of the diaphragms. A capacitance generated between the electrode portion and each of the fixed electrode changes due to a variance in the distance between the electrode portion and each of the fixed electrode, and a differential pressure is detected, based on this change in capacitance.
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