Denso Corporation

Tatsuya Kamiya

Itaru Ishii

Tomoki Tanemura

Takashi Aoki

Tetsuya Katoh

An ultrasonic sensor includes: an ultrasonic element provided to transmit or receive an ultrasonic wave propagating along a directional axis; and an element housing case that includes a case diaphragm having a thickness direction along the directional axis. A resonant space is defined between the case diaphragm and the ultrasonic element for the propagating wave, by housing the ultrasonic element while separating the ultrasonic element from the case diaphragm. A horn shape is defined in the element housing case in which a width of the resonant space in a direction orthogonal to the directional axis is reduced as the resonant space extends in an axial direction parallel to the directional axis.

Ultrasonic sensor

An ultrasonic sensor includes: an element storage case including a case-side diaphragm having a thickness direction along a directional axis; and an ultrasonic element accommodated in the element storage case and spaced apart from the case-side diaphragm. The ultrasonic element includes an element-side diaphragm having the thickness direction along the directional axis and provided by a thin part of a semiconductor substrate. The semiconductor substrate is arranged to provide a closed space between the case-side diaphragm and the element-side diaphragm. The semiconductor substrate is fixed and supported by the element-storage case.

An ultrasonic sensor includes an ultrasonic element and an element accommodation case. A side wall portion of the element accommodation case has a tubular shape surrounding a directional central axis. A bottom wall portion and a top wall portion of the element accommodation case cover ends of the side wall portion in a direction along the directional central axis. The top wall portion has a diaphragm portion. The bottom wall portion supports the ultrasonic element. For example, the ultrasonic element is opposed to the diaphragm portion across a gap defining an interval corresponding to an integral multiple of half of a wavelength of ultrasonic vibration. Alternatively, the diaphragm portion is formed of a material having an acoustic impedance of 50&#xd7;10Pa&#xb7;s/m or more and 5000&#xd7;10Pa&#xb7;s/m or less, and has a thickness of 1 mm or less.

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Kariya, Japan

Tatsuya Kamiya