Vibrating gyrosensor driven with offset potential
View Patent ↗A vibrating gyrosensor includes a support substrate on which a wiring pattern having lands is formed. A vibrating element is mounted on a surface of the support substrate. The vibrating element includes a base part having a mounting surface on which a number of terminals connectable to the lands is formed. A vibrator part integrally projects from a side of the base part and has a substrate-facing surface coplanar with the mounting surface of the base part. The vibrator part has a first electrode layer, a piezoelectric layer, and a second electrode layer which are laminated on the substrate-facing surface. The vibrator part vibrates when an AC signal is applied between the first and second electrode layers. The central electric field strength of the AC signal is set at a position shifting to the positive direction from the center of a hysteresis loop of the piezoelectric layer.
1. A vibrating gyrosensor comprising:
a support substrate with a wiring pattern having a plurality of lands;
a vibrating element mounted on a surface of the support substrate; and
an AC driving circuit operatively coupled to the vibrating element,
wherein,
the vibrating element includes a base part having a mounting surface with a plurality of terminals connectable to the lands thereon,
a vibrator part integrally projects from one of the sides of the base part and has a substrate-facing surface coplanar with the mounting surface of the base part,
the vibrator part has a first electrode layer, a piezoelectric layer, and a second electrode layer which are laminated on the substrate-facing surface, in that order, and the vibrator part vibrates when an AC signal is applied by the AC driving circuit between the first and second electrode layers, and
the AC driving circuit is configured such that the central electric field strength of the AC signal is set at a position shifting to the positive direction from the center of a hysteresis loop of the piezoelectric layer.
2. The vibrating gyrosensor described in claim 1 , wherein the AC driving circuit is configured such that a shift amount of the central electric field strength of the AC signal is 15 V/μm or less.
3. The vibrating gyrosensor described in claim 1 , wherein the first electrode layer is connected to a ground potential.
4. The vibrating gyrosensor described in claim 1 , wherein a plurality of the vibrating elements are mounted on the support substrate so that the respective vibrator parts have different axial directions.
5. The vibrating gyrosensor described in claim 4 , wherein the plurality of vibrating elements are driven with an operating frequency difference of 1 kHz or more.
6. The vibrating gyrosensor described in claim 4 , wherein a circuit element and a plurality of electronic components are mounted on the support substrate.
7. The vibrating gyrosensor described in claim 6 , wherein the circuit element includes an IC component, and a main mounting region for the circuit element is located at a central portion of a line connecting the mounting regions of the plurality of vibrating elements.