Capacitive pressure sensor isolating electrodes from external environment

摘要

A capacitive pressure sensor is provided which is capable of highly accurately and reliably measuring pressure over a wide range from an extremely low level to a high level without being affected by environmental changes. The capacitive pressure sensor is constructed of a first diaphragm; a second diaphragm arranged in parallel with the first diagram; a diaphragm support arranged between the first and second diaphragms for supporting the first and second diaphragms along the periphery thereof to define a space isolated from the outside; a plurality of pillars having respective ends fixed on the opposing surfaces of the first and second diaphragms for securely supporting the first and second diaphragms; a movable electrode formed on one of the opposing surfaces of the first and second diaphragms; and a fixed electrode formed in the space without contacting with the plurality of pillars and securely supported by the diaphragm support. Pressure values measured by the capacitive pressure sensor are substantially free from errors due to fluctuations in atmospheric pressure and errors caused by aging changes of residual stress on the bonding interface.