US 11,835,663 B2
Ultrasonic sensor
Tomoaki Matsushita, Nagaokakyo (JP); and Kazuhiro Ebara, Nagaokakyo (JP)
Assigned to MURATA MANUFACTURING CO., LTD., Nagaokakyo (JP)
Filed by Murata Manufacturing Co., Ltd., Nagaokakyo (JP)
Filed on May 18, 2021, as Appl. No. 17/323,098.
Application 17/323,098 is a continuation of application No. PCT/JP2019/051198, filed on Dec. 26, 2019.
Claims priority of application No. 2019-009697 (JP), filed on Jan. 23, 2019.
Prior Publication US 2021/0270949 A1, Sep. 2, 2021
Int. Cl. G01S 7/521 (2006.01); H04R 17/00 (2006.01); H10N 30/88 (2023.01); B06B 1/06 (2006.01)
CPC G01S 7/521 (2013.01) [B06B 1/0685 (2013.01); H04R 17/00 (2013.01); H10N 30/883 (2023.02)] 15 Claims
OG exemplary drawing
 
1. An ultrasonic sensor comprising:
a case including a bottom section and a peripheral wall section;
a piezoelectric device on the bottom section inside the case; and
a resin foam filler filling at least part of the case and covering the piezoelectric device, wherein
an inner surface of the case includes a first region and a second region,
a surface roughness of the first region is higher than a surface roughness of the second region,
the first region includes at least part of the bottom section and/or a portion of the peripheral wall section facing the piezoelectric device,
the second region is on the peripheral wall section and is farther from the piezoelectric device than the first region,
the resin foam filler contacts each of the first region and the second region, and
the inner surface of the case includes a step face between the first region and the second region.