Murata Manufacturing Co., Ltd.

Shinichi Sasaki

Takaaki Asada

Motonori Nakamura

Yuuma Watabe

An object detector includes a wave transmitter to transmit a modulated wave in a predetermined frequency range to an object, a first wave receiver to receive sound waves and to generate a first wave reception signal indicative of the reception of the sound waves, a second wave receiver to receive sound waves and to generate a second wave reception signal indicative of the reception of the sound waves, an adder to generate a third wave reception signal by adding the first and second wave reception signals, and a controller to detect the object based on the third wave reception signal by causing the wave transmitter to transmit the modulated wave. The second wave receiver is farther from the wave transmitter than the first wave receiver. A fluctuation range of the third wave reception signal is not greater than a fluctuation range of the first wave reception signal.

Object detector

An object detection system includes a processing circuit to perform wave transmission processing and determination processing. In the wave transmission processing, an acoustic wave generator is controlled to generate a series of acoustic waves of a time-varying frequency at target sound pressures associated with a frequency and correspond to the respective acoustic waves. In the determination processing, a received-wave signal representing an acoustic wave from a target space received by a wave receiver is acquired and it is determined whether an object is present in the target space based on the received-wave signal. Each of the target sound pressures is set based on the frequency characteristics of sensitivity of the wave receiver to an acoustic wave of a predetermined sound pressure, such that the sensitivity of the wave receiver to an acoustic wave of the target sound pressure is in a predetermined range including a predetermined value.

Object detection system

A low-profile ultrasonic wave generation device is provided that includes a drive unit having a piezoelectric member and an electrode formed on a surface of the piezoelectric member. The drive unit as a whole vibrates flexurally. The connection member is connected to a portion of the drive unit that includes a point of maximum displacement of the drive unit when the drive unit is subjected to flexural vibration. The vibrating unit is connected to the connection member. The vibrating unit vibrates due to the flexural vibration of the drive unit being transmitted by the connection member and thereby generates ultrasonic waves.

Ultrasonic wave generation device with low profile

A thermal excitation acoustic-wave-generating device includes a first heating element, a substrate that includes a main surface along which the first heating element is disposed, and a facing body that faces the substrate with the first heating element interposed therebetween. The substrate and the facing body define a path for an acoustic wave. A length of the path is close to a whole number multiple of &#xbc; of a wavelength of the acoustic wave.

Thermal excitation acoustic-wave-generating device and acoustic-wave-generating system

A thermal excitation acoustic-wave-generating device includes a first acoustic wave source that includes a first heating element and a substrate that includes a main surface along which the first heating element is disposed, a second acoustic wave source that includes a second heating element and a facing body that includes a main surface along which the second heating element is disposed, and a pair of electrodes connected to the first and second heating elements. The first and second acoustic wave sources are arranged such that the first and second heating elements are separated from each other and face each other. The pair of electrodes are disposed between the first and second acoustic wave sources.

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Nagaokakyo, Japan

Shinichi Sasaki