公开(公告)号：US20180021814A1

公开(公告)日：2018-01-25

申请号：US15721987

申请日：2017-10-02

Applicant: Murata Manufacturing Co., Ltd.

Inventor： Kosuke WATANABE ,  Satoshi ICHIHARA

IPC: B06B1/06 ,  H04R17/00 ,  G01S7/526 ,  G01S7/524 ,  G01S15/10 ,  G01S7/521

CPC classification number: B06B1/06 ,  B06B1/0215 ,  B06B1/0648 ,  G01H11/08 ,  G01S7/521 ,  G01S7/524 ,  G01S7/526 ,  G01S15/10 ,  H04R3/00 ,  H04R17/00

Abstract: 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.

公开(公告)号：US20240284801A1

公开(公告)日：2024-08-22

申请号：US18637607

申请日：2024-04-17

Applicant: Murata Manufacturing Co., Ltd.

Inventor： Noritaka KISHI ,  Masaaki TAKATA ,  Satoshi ICHIHARA

IPC: H10N30/80 ,  H10N30/20 ,  H10N30/88

CPC classification number: H10N30/802 ,  H10N30/2027 ,  H10N30/883

Abstract: An excitation circuit includes an output circuit including a series circuit including first and second switches connected to a DC power supply, and including a connection point between the first and second switches to which a piezoelectric element is connected, a current detection circuit to detect at least one of currents flowing through the first and second switches, and output a detection signal indicating a value based on the detected current, and a control circuit to execute switching processing in which the first and second switches are complementarily switched on and off at a predetermined frequency, in order to apply a voltage of the predetermined frequency from the output circuit to the piezoelectric element, and including a search mode to determine a resonant frequency of a vibrator vibrated by the piezoelectric element based on a value indicated by the detection signal outputted from the current detection circuit.

公开(公告)号：US20200144939A1

公开(公告)日：2020-05-07

申请号：US16733258

申请日：2020-01-03

Applicant: Murata Manufacturing Co., Ltd.

Inventor： Katsumi FUJIMOTO ,  Chikahiro HORIGUCHI ,  Yasuhiro KURATANI ,  Satoshi ICHIHARA ,  Kiyoyuki MIYAZAWA

IPC: H02N2/02 ,  G03B17/08 ,  G03B17/56 ,  H04N5/225

Abstract: A method of driving a vibration device including a light-transmitting body and a piezoelectric element connected to the light-transmitting body is provided to vibrate the light-transmitting body. The method atomizes and removes liquid drops sticking to the light-transmitting body. A driving voltage to vibrate the piezoelectric element is swept at a sweep speed in a range of about 1 Hz to about 50 Hz so as to sweep a vibration frequency of the piezoelectric element to cover a frequency range including both of a resonant frequency of the light-transmitting body without liquid drops sticking to the light-transmitting body and a resonant frequency of the light-transmitting body with the liquid drops sticking to the light-transmitting body.