Ultrasonic sensor
An ultrasonic sensor installable to a vehicle includes a magnetic body capable of ultrasonic vibration and an electric-magnetic converter having a conversion function between an oscillating magnetic field corresponding to the ultrasonic vibration of the magnetic body and an electric signal. The magnetic body is located on an outer surface side of an outer plate of the vehicle, which is the surface facing an external space of the vehicle. The electric-magnetic converter is located to face the magnetic body with the outer plate interposed therebetween on an inner surface side, which is a back surface of the outer surface of the outer plate.
1. An ultrasonic sensor installable to a vehicle comprising:
a magnetic body capable of ultrasonic vibration; and
an electric-magnetic converter having a conversion function between an oscillating magnetic field corresponding to the ultrasonic vibration of the magnetic body and an electrical signal; wherein
the magnetic body is located on an outer surface side of an outer plate of the vehicle, which is the surface facing an external space of the vehicle; and
the electric-magnetic converter is located to face the magnetic body with the outer plate interposed therebetween on an inner surface side, which is a back surface of the outer surface of the outer plate.
2. The ultrasonic sensor according to claim 1 , wherein
the electric-magnetic converter includes an inductor.
3. The ultrasonic sensor according to claim 2 , wherein
a power control section is further provided to control the power applied to the inductor, and
the power control section increases the applied power when ice or snow accretion occurs, compared to when ice or snow accretion does not occur.
4. The ultrasonic sensor according to claim 2 , further comprising:
a transmitter circuit provided to apply transmission power to the inductor when transmitting ultrasonic waves by exciting the magnetic body; and
a power consumption circuit provided to consume the electrical energy of the oscillating current that flows through the inductor after interruption of the transmission power.
5. The ultrasonic sensor according to claim 2 , further comprising:
a transmitter circuit provided to apply transmission power to the inductor for transmitting ultrasonic waves by exciting the magnetic body; and
a damping circuit provided to apply damping power to the inductor to generate a magnetic field that damps the magnetic body at the inductor after interruption of the transmission power.
6. The ultrasonic sensor according to claim 1 , wherein
a magnetic body support is further provided to support the magnetic body capable of ultrasonic vibration;
the magnetic body support includes a diaphragm formed in a thin plate shape, which fixedly supports the magnetic body so that the diaphragm vibrates ultrasonically while flexing and deforming together with the magnetic body that vibrates ultrasonically; and
a diaphragm support that supports the diaphragm capable of ultrasonic vibration.
7. The ultrasonic sensor according to claim 6 , wherein
defining a direction orthogonal to a thickness direction of the diaphragm as a first in-plane direction;
defining a direction orthogonal to the thickness direction and the first in-plane direction as a second in-plane direction;
defining a dimension of the diaphragm in the first in-plane direction as a first dimension; and
defining a dimension of the diaphragm in the second in-plane direction as a second dimension;
the diaphragm is formed in a shape having a longitudinal direction in the first in-plane direction so that the first dimension is longer than the second dimension.
8. The ultrasonic sensor according to claim 6 , wherein
the magnetic body is located offset from the center of the diaphragm in a plane perpendicular to the thickness direction of the diaphragm.
9. The ultrasonic sensor according to claim 6 , wherein
defining a direction orthogonal to a thickness direction of the diaphragm as a first in-plane direction;
defining a direction orthogonal to the thickness direction and the first in-plane direction as a second in-plane direction;
defining a dimension of the magnetic body in the first in-plane direction as a first dimension; and
defining a dimension of the magnetic body in the second in-plane direction as a second dimension;
the magnetic body is formed in a shape having a longitudinal direction in the first in-plane direction so that the first dimension is longer than the second dimension.