Patent ID: 11964483
Assignee: ROHM CO., LTD.
Field: Textile and paper machines (Mechanical engineering)
Classification: CPC B  H | IPC B  H

Claim 0:
1. A piezoelectric film utilization device comprising:
a cavity;
a movable film formation layer that includes a movable film disposed on the cavity and defining a top surface portion of the cavity; and
a piezoelectric element that is formed to contact a surface of the movable film at an opposite side from the cavity and having a peripheral edge receded further toward an interior of the cavity than the movable film in plan view; and
wherein the piezoelectric element includes a lower electrode formed on a surface of the movable film formation layer at the opposite side from the cavity, an upper electrode disposed at an opposite side from the movable film formation layer with respect to the lower electrode, and a piezoelectric film provided between the upper electrode and the lower electrode,
the upper electrode has a thin portion at least at a portion of a peripheral edge portion,
the lower electrode includes a main electrode portion in contact with a lower surface of the piezoelectric film and portions extending outward from a periphery of the main electrode portion, and
the piezoelectric film utilization device further includes:
a hydrogen barrier film covering a front surface of the movable film formation layer, front surfaces of the piezoelectric element, and front surfaces of the lower electrode besides the main electrode portion; and
an insulating film laminated on the hydrogen barrier film,
wherein the hydrogen barrier film and the insulating film have a cutout portion at a position corresponding to a region surrounded by a peripheral edge portion of a front surface of a central portion of the upper electrode.