An ultrasonic water jet apparatus includes a water accumulation part in which the water supplied from a water supply source is temporarily accumulated, a jet port that jets the water accumulated in the water accumulation part, and a piezoelectric vibration plate including a dome part that is disposed opposed to the jet port in the water accumulation part and propagates the ultrasonic vibration to the water accumulated in the water accumulation part, a flange part that projects outward in the radial direction from a peripheral edge of the dome part, and an annular plate that projects outward in the radial direction from a peripheral edge of the flange part.

A vibration device includes a bimorph type piezoelectric element having a first main surface and a second main surface facing each other and a vibration member bonded to the second main surface of the piezoelectric element. The piezoelectric element has a first active region disposed closer to the first main surface between the first and second main surfaces and a second active region disposed closer to the second main surface than the first active region between the first and second main surfaces. When a force generated in the first active region is F1, a force generated in the second active region is F2, and a force by which the vibration member restrains the second active region is Fr, F2F1Fr is satisfied.

A vibration element includes: a base; an arm continuous with the base; a first electrode that includes a first layer of titanium nitride and a second layer containing nitrogen, titanium, and oxygen, and is disposed on the arm; an aluminum nitride layer in contact with the second layer; and a second electrode disposed on the aluminum nitride layer.

An apparatus includes a first support member, a second support member and one or more electro-active polymer members between the first support member and the second support. The one or more electro-active polymer members include a first end configured to be coupled to the first support member, a second end configured to be coupled to the second support member and a middle portion located between the first end and the second end, where the middle portion includes a curved member in a first state of the one or more electro-active polymer members. A curved shape of the one or more electro-active polymer members is configured to create linear movement in a vertical direction, by bending in a curved direction.

An optical device includes: two non-waveguide regions arranged in a second direction intersecting a first direction with a spacing therebetween; an optical waveguide region that is located between the two non-waveguide regions, contains a liquid crystal material, and propagates light in the first direction; and an alignment film that aligns the liquid crystal material. Each of the two non-waveguide regions includes a low-refractive index member having a lower refractive index than the liquid crystal material. The alignment film is located between the liquid crystal material and the low-refractive index members.

Piezoelectric transducers are provided. The piezoelectric transducer includes a first piezoelectric layer, a second piezoelectric layer disposed on at least a portion of the first piezoelectric layer, and a middle electrode layer disposed between the first and second piezoelectric layers, where the middle electrode layer includes an inner region and an outer region spaced apart from the inner region. Methods of making the piezoelectric transducers are also provided. The piezoelectric transducers and methods find use in a variety of applications, including devices, such as electronics devices having one or more (e.g., an array) of the piezoelectric transducers.

A vibration device includes a piezoelectric element and an adhesive layer. The piezoelectric element includes a first principal surface and a second principal surface opposing each other. The adhesive layer is disposed on the first principal surface and is in contact with the first principal surface. A tensile strength of the adhesive layer is 10 N/cm or more and 48 N/cm or less.

An acoustic device includes a piezoelectric element, an attachment member to which the piezoelectric element is attached, and a spacer. The piezoelectric element includes first and second principal surfaces opposing each other. The attachment opposes the first principal surface. The spacer is disposed between the piezoelectric element and the attachment member in such a manner as to form an acoustic space between the piezoelectric element and the attachment member. The spacer includes an adhesive layer including a principal surface in contact with the first principal surface and a principal surface in contact with the attachment member.

A vibration device is provided with reduced thickness and size while maintaining vibration strength. The vibration device includes a first elastic plate with first and second ends and a first planar section disposed between the first and second ends. Moreover, a second elastic plate is joined to the second end of the first elastic plate and includes a second planar section opposing the first planar section of the first elastic plate. The second elastic plate has a flexural rigidity that is higher than that of the first elastic plate. In addition, a piezoelectric vibrating element is disposed on in the first planar section of the first elastic plate to face the second elastic plate. A weight can be attached to the first end of the first elastic plate to facilitate vibration.

A transducer (140) having a mechanical impedance over an operative frequency range and having a desired power coupling (145) to a load over the operative frequency range comprises a piezoelectric device (141) having a frequency distribution of modes in the operative frequency range; and an overmould (143). The overmould (143) is arranged to surround at least part of the piezoelectric device (141); and the parameters of the overmould (143) are selected to provide a required impedance matching between the mechanical impedance of the transducer (140) and the mechanical impedance of the load. An alternative transducer comprises a mounting means for holding a discrete portion of at least a part of the periphery of the piezoelectric device wherein the parameters of the mounting means are selected to provide a required boundary condition for the periphery of the piezoelectric device whereby the desired power coupling between the transducer and the load is provided.