Vibration gyro sensor, control circuit, and electronic apparatus

1. A vibration gyro sensor, comprising:

a vibration element including a piezoelectric element group which has (a) a first side provided with a drive electrode and detection electrodes and (b) a second side opposed to the first side and provided with a common electrode, the vibration element vibrating due to application of a drive signal and generating an output signal containing a detection signal corresponding to Coriolis force from the detection electrodes;

bias means to apply a bias voltage to the detection electrodes;

an oscillation circuit configured to output a signal for causing vibration of the vibration element and apply the signal for causing vibration as input to the drive electrode as the drive signal based on the output signal generated by the detection electrodes; and

a phase inversion circuit configured to receive input from the oscillation circuit and output an inversion signal, said inversion signal being obtained by inverting a phase of the signal output from the oscillation circuit and apply the inversion signal as input to the common electrode,

wherein,

the vibration element includes a base vibration body in which conductive plating is provided as an exterior surface of each side of the base vibration body, and

the conductive plating is the common electrode of the piezoelectric element group.

2. The vibration gyro sensor according to claim 1 , wherein the detection electrodes include a first detection electrode generating a first signal and a second detection electrode generating a second signal for obtaining the detection signal based on a difference between the first signal and the second signal, and

the vibration gyro sensor further comprises an addition circuit adding the first signal obtained from the first detection electrode and the second signal obtained from the second detection electrode.

3. A vibration gyro sensor, comprising:

a vibration element including a piezoelectric element which has (a) a first side provided with a drive electrode and detection electrodes, the drive electrode being formed between the detection electrodes, and (b) a second side opposed to the first side and provided with a common electrode, the vibration element vibrating due to application of a drive signal and generating output signals containing detection signals corresponding to Coriolis force from the detection electrodes;

bias means to apply a bias voltage to the detection electrodes;

an oscillation circuit configured to output a signal for causing vibration of the vibration element and apply the signal for causing vibration as input to the drive electrode as the drive signal based on the output signals generated by the detection electrodes; and

a phase inversion circuit configured to receive input from the oscillation circuit and output an inversion signal, said inversion signal being obtained by inverting a phase of the signal output from the oscillation circuit and apply the inversion signal as input to the common electrode,

wherein,

the common electrode is formed on a substrate of the vibration element, the substrate being on a side of the common electrode that is opposite to the piezoelectric element.

4. The vibration gyro sensor according to claim 3 , wherein the vibration element includes a vibration arm to which the piezoelectric element is mounted, and a base body having a lead electrode group for external connection of the drive electrode and the detection electrodes and which supports the vibration arm.

5. A control circuit, comprising:

bias means to apply a bias voltage to detection electrodes of a vibration element, the vibration element including a piezoelectric element group which has (a) a first side provided with a drive electrode and the detection electrodes and (b) a second side opposed to the first side and provided with a common electrode, the vibration element vibrating due to application of a drive signal and generating an output signal containing a detection signal corresponding to Coriolis force from the detection electrodes;

an oscillation circuit configured to output a signal for causing vibration of the vibration element and apply the signal for causing vibration as input to the drive electrode as the drive signal based on the output signal generated by the detection electrodes; and

a phase inversion circuit configured to receive input from the oscillation circuit and output an inversion signal, said inversion signal being obtained by inverting a phase of the drive signal output from the oscillation circuit and apply the inversion signal as input to the common electrode,

wherein,

the vibration element includes a base vibration body in which conductive plating is provided as an exterior surface of each side of the base vibration body, and

the conductive plating is the common electrode of the piezoelectric element group.

6. A control circuit, comprising:

bias means to apply a bias voltage to detection electrodes of a vibration element including a piezoelectric element which has a first side provided with a drive electrode and the detection electrodes and a second side opposed to the first side and provided with a common electrode, the vibration element vibrating due to application of a drive signal and generating output signals containing detection signals corresponding to Coriolis force from the detection electrodes;

an oscillation circuit configured to output a signal for causing vibration of the vibration element and apply the signal for causing vibration as input to the drive electrode as the drive signal based on the output signals generated by the detection electrodes; and

a phase inversion circuit configured to receive input from the oscillation circuit and output an inversion signal, said inversion signal being obtained by inverting a phase of the signal output from the oscillation circuit and apply the inversion signal as input to the common electrode,

wherein,

the common electrode is formed on a substrate of the vibration element, the substrate being on a side of the common electrode that is opposite to the piezoelectric element.

7. An electronic apparatus, comprising:

a vibration gyro sensor including:

a vibration element including a piezoelectric element group which has a first side provided with a drive electrode and detection electrodes and a second side opposed to the first side and provided with a common electrode, the vibration element vibrating by application of a drive signal and generating an output signal containing a detection signal corresponding to Coriolis force from the detection electrodes,

bias means to apply a bias voltage to the detection electrodes,

an oscillation circuit configured to output a signal for causing vibration of the vibration element and apply the signal for causing vibration as input to the drive electrode as the drive signal based on the output signal generated by the detection electrodes, and

a phase inversion circuit configured to receive input from the oscillation circuit and output an inversion signal, said inversion signal being obtained by inverting a phase of the signal output from the oscillation circuit and apply the inversion signal as input to the common electrode; and

a main body to which the vibration gyro sensor is mounted,

wherein,

the vibration element includes a base vibration body in which conductive plating is provided as an exterior surface of each side of the base vibration body, and

the conductive plating is the common electrode of the piezoelectric element group.