1. Field of the Invention
The present invention relates to an oscillating angular speed sensor.
2. Description of Related Art
JP-A-2002-500961 discloses a micro mechanical component produced by connecting a substrate wafer and a cap wafer. The substrate wafer has a surface structure to detect a physical quantity. The cap wafer has a recess opposing to the surface structure of the substrate wafer, such that the surface structure can be prevented from having a contact from outside. The cap wafer is bonded to the substrate wafer, and the surface structure is sealed in a space between the wafers.
The space between the wafers is a single closed space, such that the surface structure is arranged in the single space. When the surface structure operates as an oscillating angular speed sensor, the sensor includes a detector to detect an angular speed, and a driving portion to drive the detector in a single direction. In this case, the detector and the driving portion are arranged in the same single space.
However, in a case that gas is filled in the space, when the driving portion drives the detector, oscillation amplitude of the detector may be affected by a damping of the gas. Therefore, it is difficult for the driving portion to drive the detector in the single direction, such that a detection accuracy of the sensor may become worse. Thus, the space may be required to be vacuumed for the driving portion, so as to secure the oscillation amplitude of the detector. However, when the space is vacuumed, the gas cannot have an effect of the damping. Therefore, electrodes of the detector may have damage due to collision or sticking, when an impact is applied to the sensor.
That is, a space suitable for the detector, and a space suitable for the driving portion are different from each other.