公开(公告)号：US20240003851A1

公开(公告)日：2024-01-04

申请号：US18470608

申请日：2023-09-20

Applicant: DENSO CORPORATION

Inventor： Ryoichi KAIZU ,  Yuki INABA ,  Tomomi OKUMURA ,  Toshifumi HOSONO

IPC: G01N29/06 ,  B06B1/02 ,  G01N29/34

CPC classification number: G01N29/0672 ,  B06B1/0215 ,  G01N29/343 ,  G01N2291/0231

Abstract: A power module comprises an element and an insulated circuit board having a laminated portion. The laminated portion includes a first metal layer, a bonding layer interposed between an element and the first metal layer, a second metal layer, and a resin layer interposed between the first metal layer and the second metal layer. The insulated circuit board has a pair of laminated portions provided so as to sandwich the element. The laminated portions are configured so that ultrasonic pulses emitted from an outside of the second metal layer toward the element have the following relationship of detection time periods. A time period in which the ultrasonic pulse travels two roundtrips in the second metal layer is longer than a time period in which the ultrasonic pulse travels one roundtrip in a range from the second metal layer to the element.