The interface region may include a region in which first intensity is higher than second intensity and in which the first intensity is higher than third intensity, where a degree of orientation of the (−211) crystal face of the second layer is denoted as the first intensity, the degree of orientation of the (−111) crystal face of the second layer is denoted as the second intensity, and the degree of orientation of the (002) crystal face of the second layer is denoted as the third intensity. The surface-layer region may include a region in which the first intensity is higher than the third intensity and in which the second intensity is higher than the third intensity.

An electronic device includes a display element, a piezoelectric element, and a cushioning element. The display element has a display surface and a non-display surface opposite to the display surface. The piezoelectric element is disposed on the non-display surface. The cushioning element is disposed between the display element and the piezoelectric element, and a space is surrounded by the display element, the piezoelectric element, and the cushioning element.

An acoustic wave device includes a piezoelectric substrate made of LiNbO.sub.3 or LiTaO.sub.3 and including first and second main surfaces that face each other, an IDT electrode provided on the first main surface of the piezoelectric substrate, and a Li.sub.2CO.sub.3 layer provided on the second main surface of the piezoelectric substrate.

A microfluidic valve formed in a body having a first and a second surface; an inlet channel extending in the body from the second surface; a first transverse channel extending in the body in a transverse direction with respect to the inlet channel; and an outlet channel extending in the body from the first surface. The inlet channel, the first transverse channel and the outlet channel form a fluidic path. The microfluidic valve further has an occluding portion, formed by the body and extending over the transverse channel; and a piezoelectric actuator coupled to the occluding portion and configured to move the occluding portion from an opening position of the valve, where the occluding portion does not interfere with the fluidic path, and a closing position of the valve, where the occluding portion interferes with and interrupts the fluidic path.

A vibration generating device 10 includes: a diaphragm 11; and a first piezoelectric actuator 12 and a second piezoelectric actuator 13 attached on an upper surface 11a and a lower surface 11b of the diaphragm 11, respectively, so as to sandwich the diaphragm 11 therebetween in a vicinity of an end surface of the diaphragm 11, wherein, in a top view of the upper surface 11a of the diaphragm 11, the first piezoelectric actuator 12 is disposed at a position shifted with respect to the second piezoelectric actuator 13.

An apparatus includes a vibration member and a first cover disposed at a rear surface of the vibration member. The apparatus also includes a first vibration apparatus disposed at a rear surface of the first cover and configured to vibrate the vibration member. The apparatus includes a first enclosure member disposed at the rear surface of the first cover and at the rear surface of the vibration member. The apparatus also includes a first rear vibration member disposed at the first enclosure member.

In one embodiment, a transducer comprises a first piezoelectric stack comprising a piezoelectric material; a first layer in contact with the piezoelectric stack; and a base structure beneath the first layer. The first layer has a first displacement between a first portion of the base structure and the first layer, and the first displacement is configurable by a first bias voltage received by the transducer.

A first main plate has a first principal surface and a second principal surface. A second main plate has a third principal surface, a fourth principal surface, and an aperture. A piezoelectric element is provided on the first main plate and vibrates the first main plate. A first frame is disposed outside an outer peripheral end of the first main plate. First connecting portions connect the first main plate and the first frame to each other. Apertures are formed between the first connecting portions and connect a space adjacent to the first principal surface and a space adjacent to the second principal surface to each other. The second frame is disposed outside an outer peripheral end of the first frame. A second connecting portion connects the first frame and the second frame to each other.

A fluid driving system includes a vibration unit, a piezoelectric element, a signal transmission layer, a plane unit, and a protrusion. The piezoelectric element includes a first electrode and a second electrode electrically isolated from each other. The signal transmission layer includes a first conductive zone and a second conductive zone. The first electrode of the piezoelectric element is electrically connected to the first conductive zone of the signal transmission layer, and the second electrode of the piezoelectric element is electrically connected to the second conductive zone of the signal transmission layer. The plane unit has at least one hole. The piezoelectric element, the signal transmission layer, and the plane unit are located at one side of the vibration unit. The protrusion is located between the vibration unit and the plane unit, and the protrusion corresponds to and protrudes toward the at least one hole.

A vibration apparatus includes a vibration device. The vibration device includes a vibration portion including a piezoelectric material, a first electrode portion at a first surface of the vibration portion and configured as a plurality of circular patterns, and a second electrode portion at a second surface different from the first surface of the vibration portion and configured as a single electrode, and the vibration device generates an ultrasound wave.