Murata Manufacturing Co., Ltd.

Kosuke Watanabe

Motoyasu Nakao

Jun Tabota

Kenji Matsuo

Satoshi Ichihara

Akio Fujita

Koji Nanbu

An ultrasonic apparatus includes a transmitting circuit, an ultrasonic transducer, a receiving circuit, and a capacitance measuring circuit. The ultrasonic transducer is a three-terminal ultrasonic transducer that includes a transmitting electrode, a receiving electrode, and a common electrode. The transmitting circuit outputs a driving signal to the transmitting electrode to cause the ultrasonic transducer to transmit ultrasonic waves. The receiving circuit receives a receive signal from the receiving electrode. The capacitance measuring circuit is electrically connected to the receiving electrode to measure the electrostatic capacitance of the ultrasonic transducer.

Ultrasonic apparatus

An ultrasonic apparatus includes an ultrasonic transducer, a transmitting circuit, a receiving circuit, a Q-factor measuring circuit, and a frequency measuring circuit. The ultrasonic transducer is a three-terminal ultrasonic transducer that includes a transmitting electrode, a receiving electrode, and a common electrode. The transmitting circuit outputs a driving signal to the transmitting electrode to cause the ultrasonic transducer to transmit ultrasonic waves. The receiving circuit receives a receive signal from the receiving electrode. The frequency measuring circuit measures a resonant frequency of the ultrasonic transducer from a reverberation signal in the receive signal. The Q-factor measuring circuit measures a Q factor of the ultrasonic transducer from the reverberation signal in the receive signal.

An ultrasonic sensor includes a piezoelectric body including a transmission region for an ultrasonic wave and a reception region for a reflected wave of the ultrasonic wave, a common electrode in the transmission region and the reception region, a transmission electrode in the transmission region, a reception electrode in the reception region; and a semiconductor element that is electrically connected to the transmission electrode and the reception electrode and switches an electrical path between a conductive state and a non-conductive state. The semiconductor element puts the path into the conductive state after application of the alternating-current voltage is stopped. Thus, a reverberation signal, output from the reception region in accordance with a reverberant vibration of the ultrasonic wave, is fed back to the transmission electrode.

Ultrasonic sensor and control method therefor

An ultrasonic sensor including a case having a bottom portion, and a piezoelectric element that is bonded to an inner surface of the bottom portion and performs bending vibration together with the bottom portion. The piezoelectric element includes a piezoelectric layer having a transmission region and a reception region, a common electrode, a transmission electrode opposing the common electrode with the transmission region interposed therebetween, and a reception electrode opposing the common electrode with the reception region interposed therebetween. The transmission region and the reception region are formed at positions adjacent to each other.

Ultrasonic sensor

A vibrator of an angular velocity sensor includes detection beam portions extending from a central base portion in a cross shape, and drive beam portions between and connected to two adjacent detection beam portions. Each of the detection beam portions includes a base-end detection beam connected to the central base portion, and a left detection beam and a right detection beam. The left detection beam is connected to one of the drive beam portions that is located on the left of the corresponding one of the detection beam portions, and the right detection beam is connected to one of the drive beam portions that is located on the right of the corresponding one of the detection beam portions. The drive beam portions are driven to vibrate in a direction toward the central base portion and a direction away from the central base portion so that each two facing ones of the drive beam portions are in the same phase and each two adjacent ones of the drive beam portions are in the opposite phases.

Angular velocity sensor

A vibrating body of an angular velocity detection element includes detection beams extending in a cross shape from a central base and external connection beams and internal connection beams connected between adjacent detection beams. The detection beams each include a base end detection beam that is connected to the central base and a central detection beam, a left detection beam and a right detection beam that define three prongs. The central detection beam is connected to the external connection beams on both sides, the left detection beam is connected to the internal connection beam on the left side and the right detection beam is connected to the internal connection beam on the right side. The adjacent external connection beams undergo driven vibration so as to be displaced in directions so as to have mirror relationships with each other with the detection beams interposed between the external connection beams acting as boundaries therebetween.

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Nagaokakyo, Japan

Kosuke Watanabe