US Patent 11181431 Pressure sensor chip

A curved recess in a stopper includes a groove-pattern region and a groove-free region. When a sensor diaphragm reaches a bottom of the curved recess in the stopper, a groove-free region is divided into a ring-shaped first region with which a sensor diaphragm is in close contact and a ring-shaped second region disposed between an inner wall surface of a ring-shaped wall and the ring-shaped first region. The first region serves as a sealing region and the second region serves as a confinement region so that a pressure transmitting medium that remains in a space adjacent to the inner wall surface of the ring-shaped wall is confined in the confinement region, and abnormal deformation of the sensor diaphragm is prevented.