Abstract: A piezoelectric speaker comprises a frame, a piezoelectric element, a diaphragm, an edge, a spacer, a cover and a supporting portion. The frame has an upper surface and a lower surface in an up-down direction. The diaphragm has an outer peripheral end in a horizontal plane perpendicular to the up-down direction. The cover has an outer peripheral end in the horizontal plane. In the horizontal plane, the outer peripheral end of the diaphragm is positioned inside the outer peripheral end of the cover. The edge supports the outer peripheral end of the diaphragm so that the outer peripheral end of the diaphragm is freely vibratable. The spacer is fixed to both of the piezoelectric element and the diaphragm in the up-down direction. The cover is positioned above the diaphragm in the up-down direction. The supporting portion is positioned on the frame and supports the cover.

Abstract: A piezoelectric speaker (100, 200, . . . , or 500) includes a piezoelectric element (1), and a metal vibration part (2, 22, . . . , or 352) to which the piezoelectric element (1) is made to adhere through an adhesive part (3). The piezoelectric element (1) is a substantially rectangular plate. The metal vibration part (2, 22, . . . , or 352) includes a substantially rectangular plate-shaped part (2, 12a, 32a, . . . , 132a, or the like) vibrated by the piezoelectric element. A frequency of a natural vibration mode of the piezoelectric element (1) and a frequency of a natural vibration mode of the metal vibration part (2, 12a, 32a, . . . , 132a, or the like) are set to be different from each other.

Abstract: A vibration transfer structure (300) and a piezoelectric speaker (400) capable of achieving excellent vibration characteristics even when a piezoelectric device (1) is used. A vibration transfer structure (300) according to an aspect of the present disclosure includes a plate-like piezoelectric device (1) supported at both ends thereof, a diaphragm (3) disposed to be opposed to the piezoelectric device (1), a plurality of spacers (5) configured to connect the piezoelectric device (1) with the diaphragm (3), and an elastic body (24) disposed on a periphery (3a) of the diaphragm (3).

Abstract: An electronic device is provided with a main surface member which is used as a vibrating plate, a case which supports the main surface member and a sound generating unit which is attached to the case to generate sound by vibrating the main surface member. The sound generating unit is provided with a piezoelectric plate and a protective member. The piezoelectric plate has a longitudinal direction in a first horizontal direction and has an upper surface, a lower surface and a plurality of side surfaces. The protective member has a supporting portion covering the lower surface of the piezoelectric plate and supporting the piezoelectric plate, a protective portion provided to the supporting portion to cover at least one of the side surfaces of the piezoelectric plate and an attached portion attached to the case.

Abstract: A piezoelectric transformer (21) comprises a piezoelectric rectangular body (23) equally divided into first to fourth regions (A1, A2, A3, and A4) in a longitudinal direction. The first and the fourth regions (A1, A4) are provided with plane electrodes (24, 25, 26, and 27) as input electrodes and polarized in a thickness direction. Strip-like electrodes (30, 31) are formed at the boundary between the remaining second and third regions (A2, A3) as output electrodes. An AC input voltage having a frequency corresponding to a wavelength equal to a half of the length of the piezoelectric rectangular body is applied to the input electrodes to vibrate the piezoelectric plate in a two-wavelength resonance mode. A voltage produced by a piezoelectric effect in response to the vibration is extracted from an output terminal. The transformer is small in size, low in vibration rate and heat generation, and excellent in efficiency.

Abstract: A piezoelectric transformer (21) comprises a piezoelectric rectangular body (23) having equally divided first to fourth regions (A1, A2, A3, and A4) in a longitudinal direction. The first and the fourth regions (A1, A4) are provided with plane electrodes (24, 25, 26, and 27) as input electrodes and polarized opposite to each other in a thickness direction. Strip-like electrodes (30, 31) are formed at the boundary between the two remaining regions (A2, A3) as output electrodes. An AC input voltage having a frequency corresponding to a wavelength equal to of the length of the piezoelectric body is applied to the input electrodes to vibrate the piezoelectric plate in a one-wavelength resonance mode. A voltage produced due to the piezoelectric effect in response to the vibration is extracted from the output electrode. The transformer is small in size, low in vibration rate and heat generation, and excellent in efficiency.

Abstract: A piezoelectric transformer has input and output terminal electrodes (12c, 12d, 13c, 13d) exposed on a bottom surface thereof. The terminal electrodes are mechanically and electrically connected to connection portions (15a-15d) of a flexible printed circuit (18) for connecting with an external circuit. The transformer is held between a base element (21b, 22) and a cover (21a, 23, 25) coupled to each other. The base element may be a circuit board on which the transformer should be mounted.

Abstract: A piezoelectric transformer element is wrapped together with primary lead members and secondary lead members by a thin soft insulating sheet, with the primary and secondary lead members being exposed outside the wrapping sheet, so that the transformer element is small in size, and easy in handling, and mounting operation on a circuit board. The primary and secondary lead members can be formed of a flexible flat cable. In an electric power supply device using the piezoelectric transformer element, the transformer element, and the flexible flat cable are wrapped by the wrapping sheet together with a portion of a circuit board on which the transformer element and other circuit elements are mounted.