A flexible piezoelectric thin film, and method of manufacture, has a polyvinyl alcohol (PVA)-glycine-PVA sandwich heterostructure. The thin film is manufactured by evaporating the solvent from a glycine-PVA mixture solution. The film automatically assembles into the PVA-glycine-PVA sandwich heterostructure as it is salted out. Strong hydrogen bonding between the oxygen atoms in glycine and hydroxyl groups on PVA chains are responsible for the nucleation and growth of the piezoelectric -glycine and alignment of the domain orientation.

A method and structure for a transfer process for an acoustic resonator device. In an example, a bulk acoustic wave resonator (BAWR) with an air reflection cavity is formed. A piezoelectric thin film is grown on a crystalline substrate. A first patterned electrode is deposited on the surface of the piezoelectric film. An etched sacrificial layer is deposited over the first electrode and a planarized support layer is deposited over the sacrificial layer, which is then bonded to a substrate wafer. The crystalline substrate is removed and a second patterned electrode is deposited over a second surface of the film. The sacrificial layer is etched to release the air reflection cavity. Also, a cavity can instead be etched into the support layer prior to bonding with the substrate wafer. Alternatively, a reflector structure can be deposited on the first electrode, replacing the cavity.

A production method for a composite substrate according to the present invention comprises (a) a step of mirror-polishing a piezoelectric-substrate side of a laminated substrate formed by bonding a piezoelectric substrate and a support substrate; (b) a step of performing machining using an ion beam or a neutral atom beam so that a thickness of an outer peripheral portion of the piezoelectric substrate is larger than a thickness of an inner peripheral portion and a difference between a largest thickness and a smallest thickness of the inner peripheral portion of the piezoelectric substrate is 100 nm or less over an entire surface; and (c) a step of flattening the entire surface of the piezoelectric substrate to remove at least a part of an altered layer formed by the machining using the ion beam or the neutral atom beam in the step (b).

A piezoelectric element includes: a piezoelectric body; and a first electrode which is disposed on the piezoelectric body, and in which in a plan view viewed from a direction where the first electrode and the piezoelectric body are aligned, a region which is a surface of the piezoelectric body on which the first electrode is disposed, located at a vicinity of the first electrode, and within 10 m from an outer edge of the first electrode has a crystal surface.

A piezoelectric element includes a piezoelectric element main body as a laminated body of a first electrode layer, a piezoelectric layer disposed on the first electrode layer, and a second electrode layer disposed on the piezoelectric layer, and a metal layer disposed on the second electrode layer via an insulating layer, the piezoelectric layer extends from an inner side of at least a part of an overlapping part of an outer peripheral edge of the second electrode layer overlapping an outer peripheral edge of the piezoelectric element main body to an outer side, and the metal layer and the insulating layer extend from an inner side of at least a part of the overlapping part to an outer side to overlap the piezoelectric layer on an outer side of an outer peripheral edge of the second electrode layer.

An actuator device includes: an actuator including first contacts arranged in a first direction; and a wire member including second contacts and joined to the actuator. The second contacts are arranged in the first direction and respectively connected to the first contacts. Each of particular contacts as the first contacts or the second contacts has a protruding and recessed portion including: at least two protrusions; and a recess between the at least two protrusions. The particular contacts include: at least one central-region contact disposed on a central region in the first direction; and at least one end-region contact disposed nearer to an end region than to the central region in the first direction. The protruding and recessed portion of each of the at least one central-region contact is different in shape from the protruding and recessed portion of each of the at least one end-region contact.

An ultrasonic piezoelectric transducer device includes a transducer array consisting of an array of vibrating elements, and a base to which the array of vibrating elements in the transducer array are attached. The base include integrated electrical interconnects for carrying driving signals and sensed signals between the vibrating elements and an external control circuit. The base can be an ASIC wafer that includes integrated circuitry for controlling the driving and processing the sensed signals. The interconnects and control circuits in the base fit substantially within an area below the array of multiple vibrating elements.

A method for producing a piezoelectric element includes a step of forming a first electrode layer, a step of forming a piezoelectric body layer on the first electrode layer, a step of forming a second electrode layer on the piezoelectric body layer, a step of patterning the second electrode layer, a step of patterning the piezoelectric body layer by wet etching, and a step of forming an organic insulating layer on a side surface of the patterned piezoelectric body layer.

A single photo mask can be used to define the three critical layers for the piezoelectric MEMS device, specifically the top electrode layer, the piezoelectric material layer, and the bottom electrode layer. Using a single photo mask removes the misalignment source caused by using multiple photo masks. Furthermore, in certain exemplary embodiments, all electrical interconnects use underpass interconnect. This simplifies the process for defining the device electrodes and the process sequence for achieving self-alignment between the piezoelectric element and the top and bottom electrodes. This self-alignment is achieved by using an oxide hard mask to etch the critical region of the top electrode, the piezoelectric material, and the bottom electrode with one mask and different etch chemistries depending on the layer being etched.

A control circuit includes: an angular velocity calculator calculating an angular velocity of a mirror based on an angle of the mirror; a target angular velocity calculator calculating a target value of the angular velocity; a resonance frequency detector detecting a frequency of vibration of the mirror using the angular velocity and target value; a drive waveform generator generating a drive signal having sawtooth waveform; and an unnecessary vibration controller optimizing the drive signal to reduce an unnecessary vibration of the mirror based on the frequency of vibration of the mirror and providing piezoelectric elements with voltage according to the optimized drive signal. The resonance frequency detector detects the frequency of vibration of the mirror using a waveform and the target value of the angular velocity of the mirror during a duration in which the drive signal is transmitted to the unnecessary vibration controller from the drive waveform generator.