Back to results
US 8,771,192 B2Granted
Ultrasonic sensor and electronic device
AssigneeSeiko Epson Corporation
InventorKazuyuki Kano
Life of this patent
Estimating the term…
Abstract
The ultrasonic sensor includes, on the same substrate, transmitter elements, receiver elements, a potential controller for receiver electrodes of the receiver elements, and a connection switching unit for the receiver electrodes and the potential controller. During the ultrasound transmission period of the transmitter elements, the connection switching unit connects the potential controller and the receiver electrodes. During the reception period of the receiver elements, the connection switching unit disconnects the potential controller and the receiver electrodes.
Claims16
An ultrasonic sensor comprising:
- a substrate,
- a transmitter element formed above the substrate, the transmitter element including a transmission film adapted to transmit ultrasound through oscillation, a transmission piezoelectric body for causing the transmission film to oscillate, and a pair of actuation electrodes for applying an actuation voltage to the transmission piezoelectric body;
- a receiver element formed above the substrate, the receiver element being different from the transmitter element, the receiver element including a reception film adapted to oscillate through reception of the ultrasound, a reception piezoelectric body for converting oscillation of the reception film to an electrical signal, and a pair of receiver electrodes for picking up the electrical signal that is output from the reception piezoelectric body;
- a potential controller configured to bring the receiver electrodes to a first potential;
- a connection switching unit configured to switch a connection state of the receiver electrodes and the potential controller;
- a trigger signal generator configured to keep outputting a trigger signal during a trigger output period that is set to be longer than a transmission period in which the ultrasound is transmitted by the transmitter element, and
- an actuation controller configured to output an actuation signal applied to the actuation electrodes of the transmitter element while simultaneously activating the trigger signal generator,
- during the transmission period, the connection switching unit being configured to switch to a first state in which the potential controller and the receiver electrodes are connected, the connection switching unit being configured to switch to the first state in response to commencing output of the trigger signal from the trigger signal generator, and
- during a reception period in which the ultrasound is received by the reception element, the connection switching unit being configured to switch to a second state in which the potential controller and the receiver electrodes are disconnected, the connection switching unit being configured to switch to the second state in response to termination of the output of the trigger signal.
6 more elements
An ultrasonic sensor comprising:
- a substrate having a plurality of opening portions;
- a support film covering the opening portions;
- a first piezoelectric element formed above the support film and in the inside region of a first opening portion among the opening portions in plan view;
- a second piezoelectric element formed above the support film and in the inside region of a second opening portion among the opening portions in plan view, the second piezoelectric element being a different element from the first piezoelectric element;
- a potential controller configured to supply a potential;
- a connection switching unit configured to switch a connection state of the first piezoelectric element and the potential controller;
- a trigger signal generator configured to keep outputting a trigger signal during a trigger output period that is set to be longer than a transmission period in which an actuation voltage is applied to the second piezoelectric element, and
- an actuation controller configured to output an actuation signal to the second piezoelectric element while simultaneously activating the trigger signal generator,
- the first piezoelectric element including a first piezoelectric body and a pair of first piezoelectric element electrodes connected to the first piezoelectric body, the second piezoelectric element including a second piezoelectric body and a pair of second piezoelectric element electrodes connected to the second piezoelectric body,
- during the transmission period, the connection switching unit being configured to switch to a first state in which the potential controller and the first piezoelectric element electrodes are connected, the connection switching unit being configured to switch to the first state in response to commencing output of the trigger signal from the trigger signal generator, and
- during a reception period in which an electrical signal of the first piezoelectric element is picked up, the connection switching unit being configured to switch to a second state in which the potential controller and at least one of the first piezoelectric element electrodes are disconnected, the connection switching unit being configured to switch to the second state in response to termination of the output of the trigger signal.
8 more elements
Dependencies are inferred from the claim text.