Beschleunigungssensor mit Selbsttest

摘要

A fixed base plate (10) having a rigidity and a flexible base plate (20) are so provided as to face each other. The peripheries of both the base plates are fixed on a casing (40) of a device. An acting body (30) is bonded to the lower surface of the flexible base plate. Testing electrodes (11t, 13t, 15t) are formed on the lower surface of the fixed base plate and further fixed electrodes (11, 13, 15) are formed under the testing electrodes via an insulation layer (16). Displacement electrodes (21, 23, 25) are formeed on the upper surface of the flexible base plate. When an acceleration acts on the acting body, the flexible base plate bends and the distances between the fixed electrodes and the displacement electrodes changes, causing the capacitance between the electrodes to change. The acted acceleration can be measured by measuring the capacitance changed. For testing the performance of the device, a Coulomb force is made to act on the testing electrodes and the displacment electrodes by applying voltages across both the electrodes. The flexible base plate is bent due to the Coulomb forces and there is the same state as the one when the acceleration acts. The testing of the performance becomes possible by measuring the change of the capacitance between the fixed electrodes and the displacement electrodes in this state.