A bulk acoustic wave (BAW) resonator device includes a bottom electrode disposed over a substrate and an acoustic reflector, a seed layer formed of a dielectric material disposed over the bottom electrode, a split piezoelectric layer disposed on the seed layer, and a top electrode disposed over the split piezoelectric layer. The split piezoelectric layer includes a first portion having a positive polarity due to the seed layer, a second portion having a negative polarity that is substantially opposite to the positive polarity of the first portion, and a metal interposer between the first portion and the second portion. The first portion of the piezoelectric layer has a first thickness and the second portion of the piezoelectric layer has a second thickness that is not equal to the first thickness, thereby lowering a coupling coefficient kt.sup.2 of the BAW resonator device.

A bulk acoustic wave (BAW) resonator comprises: a seed layer disposed over a substrate; a first electrode disposed over the seed layer; and a second electrode disposed over a piezoelectric layer. The seed layer has a thickness in the range of approximately 30 Å to approximately 150 Å.

The present disclosure relates to a Wafer-level-packaged Bulk Acoustic Wave (BAW) device, which includes a bottom electrode, a top electrode, a top electrode lead, a piezoelectric layer sandwiched between the bottom and the top electrodes, an enclosure, and an anti-reflective layer (ARL). Herein, an active region for a resonator is formed where the bottom electrode and the top electrode overlap. The top electrode lead is over the piezoelectric layer and extending from the top electrode. The enclosure includes a cap and an outer wall that extends from the cap toward the piezoelectric layer to form a cavity. The top electrode resides in the cavity and a first portion of the outer wall resides over the top electrode lead. The ARL, with a reflectance less than 40% R, is between the first portion of the outer wall and the top electrode lead.

An elastic wave resonator includes an interdigital transducer electrode provided on a piezoelectric substrate and including a first electrode layer made of Al or an alloy with Al as its primary component and including a first main surface on a side where the piezoelectric substrate is located and a second main surface on the opposite side from the first main surface. An SH wave is used as a propagated elastic wave. When a resonant frequency of the elastic wave resonator is fr and an anti-resonant frequency of the elastic wave resonator is fa, a minimum value of an absolute value of a distortion component in the first main surface calculated through a two-dimensional finite element method is about 1.4×10.sup.−3 or less at a frequency f expressed as:

f=fr+0.06×bw, where bw is fa−fr.

A method for manufacturing an electronic component is provided where resin adhesive rarely spreads before curing. The method includes providing a first sealing member and forming a frame-shaped glass layer on a principal surface of the first sealing member. Moreover, the first sealing member is cut into multiple first sealing members and second sealing members are bonded with resin adhesive to inner frame regions on the principal surface of the first sealing member defined by the glass layer.

A brushless electric motor is disclosed. A group of permanent magnets are physically attached to a group of piezoelectric actuators which push them toward or pull them away from a second group of permanent magnets when the piezoelectric actuators are electrically activated. The second group of permanent magnets may also be pushed and pulled with a second group of piezoelectric actuators. Alternate configurations using electromagnets are also disclosed.

A novel configuration for the groups of electromagnets which maximizes efficiency in a piezoelectrically actuated motor is also disclosed.

Disclosed examples include lens cleaning systems, drivers and operating methods, including a transducer mechanically coupled to a lens, a driver to provide an oscillating drive signal to the transducer and a controller to control the drive signal frequency to vibrate the lens at frequencies in a range of interest. The controller determines a measured resonant frequency of the lens cleaning system in the range of interest according to a transducer feedback signal and selectively performs a lens cleaning operation if the measured resonant frequency differs from a baseline resonant frequency of the lens cleaning system for a clean lens.

A filter includes: an input terminal; an output terminal; and a ladder circuit that includes one or more series acoustic wave resonators connected in series between the input terminal and the output terminal and one or more parallel acoustic wave resonators connected in parallel between the input terminal and the output terminal, and in which characteristic impedance of at least one point in a pathway between the input terminal and the output terminal in a passband is greater than at least one of input impedance of the input terminal and output impedance of the output terminal in the passband.

The present invention relates to a holder (5) for a piezoelectric component (1), having a clamping device (6) and two contact elements (8) which contain a conductive rubber material, wherein the clamping device (6) is designed to clamp the piezoelectric component (1) between the contact elements (8) in a closed state, and wherein the contact elements (8) are in electrical contact with the piezoelectric component (1) in the closed state of the clamping device (6).

A ladder filter defines a transmission filter and has a structure such that a resonator located closest to an input terminal is a parallel-arm resonator, and the parallel-arm resonator located closest to the input terminal includes a plurality of division resonators connected in parallel. At least one division resonator has a resonant frequency and an anti-resonant frequency that are located outside a passband of the ladder filter, and the remaining division resonators and parallel-arm resonators each have an anti-resonant frequency located within the passband.