Abstract: A piezoelectric thin-film resonator includes a device substrate and a laminated body provided on the device substrate and composed of a lower electrode, an upper electrode and a piezoelectric film sandwiched between the lower and upper electrodes. The laminated body has a membrane portion in which the upper and lower electrodes overlap with each other through the piezoelectric film, and a gap has a dome shape being formed between the device substrate and the lower electrode and located below the membrane portion.

Abstract: A surface acoustic wave filter includes series-arm resonators and parallel-arm resonators that are connected in a ladder-like fashion. This surface acoustic wave filter satisfies conditions expressed as: 1×106?4?2f02R2CopCos?3.1×106 where Cop is the electrostatic capacitance of the parallel-arm resonators, Cos is the electrostatic capacitance of the series-arm resonators, f0 is the center frequency, and R is the nominal impedance.

Abstract: The present invention provides the stress detection method for force sensor device with multiple axis sensor device and force sensor device employing this method, whose installation angle is arbitrary. The stress detection method includes, first and second force sensors whose detection axes are orthogonal to each other. When the detection axis of first force sensor forms angle ? with direction of detected stress Ax, and the stress component of direction perpendicular to direction of the detected stress Ax is Az, output Apx of the axis direction of first force sensor is found as Apx=?x (Ax×cos ?+Az×sin ?), and output Apz of the axis direction of the second force sensor is found as Apz=?z (Ax×sin ?+Az×cos ?), and, when ?x and ?z are detection sensitivity coefficients of first and second force sensors respectively, the detection sensitivity coefficient ?z of second force sensor is set as ?z=?x tan ?, and the detected stress Ax is found as Ax=(Apx?Apz)/?x(cos ??tan ?×sin ?).

Abstract: A resonator includes a piezoelectric thin-film provided on a main surface of a substrate, a first electrode film provided on a first surface of the piezoelectric thin-film, a second electrode film provided on a second surface of the piezoelectric thin-film, a frequency adjustment film provided on one of the first and second electrode films, the frequency adjustment film comprising a film laminate including a first adjustment film provided on said one of the first and second electrode films, and a second adjustment film provided on the first adjustment film. The first adjustment film is used for ?f adjustment, and the second adjustment film is used for correcting frequency deviations generated in the filter manufacturing process. Thus, it is possible to accurately control the center frequency of the filter in which the multiple resonators are connected.

Abstract: A filter device includes a filter element that has piezoelectric thin-film resonators arranged in series arms and parallel arms, and a package that houses the filter element in a face-down state. In this filter device, the filter element and the package are electrically connected to each other through bumps. The package includes first pad parts on which the bumps are placed, and transmission paths that electrically connect the first pad parts to the outside. The filter element includes second pad parts that are electrically connected to the first pad parts through the bumps, and wiring parts that electrically connect the second pads to the piezoelectric thin-film resonators and electrically connect the piezoelectric thin-film resonators to one another. In this structure, inductances formed with the transmission paths are connected in series to the piezoelectric thin-film resonators.

Abstract: A method is provided for making a micro-switching element. The switching element includes a substrate, two supporting members fixed to the substrate, and a movable beam bridging between the supporting members. The beam includes a membrane, a movable contact electrode and a movable driving electrode, both disposed on the membrane. The switching element also includes a pair of stationary contact electrodes facing the movable contact electrode, and a stationary driving electrode cooperating with the movable driving electrode for generation of electrostatic force. The method includes the steps of making a sacrifice layer on the substrate, making the membrane on the sacrifice layer, and subjecting the sacrifice layer to etching with the membrane intervening, so that the supporting members are formed as remaining portions of the sacrifice layer between the substrate and the membrane.

Abstract: A film bulk acoustic resonator is fabricated in the following manner. First, a base layer is formed on an insulating substrate. Then, a resonator assembly is formed on the base layer. The resonator assembly includes a first electrode held in contact with the base layer, a second electrode, and a piezoelectric layer held between the first and the second electrodes. Then, a resist layer is formed to cover the resonator assembly and the base layer. Then, a through-hole is formed in the resist layer so that the base layer is exposed via the through-hole. Then, etchant is supplied via the through-hole to make a space in the base layer under the resonator assembly. Finally, the resist layer is removed.

Abstract: A piezoelectric thin-film resonator includes a substrate, a lower electrode arranged on the substrate, a piezoelectric film arranged on the lower electrode, and an upper electrode arranged on the piezoelectric film. A region in which the upper electrode overlaps with the lower electrode through the piezoelectric film has an elliptical shape, and a condition such that 1<a/b<1.9 is satisfied where a is a main axis of the elliptical shape, and b is a sub axis thereof.

Abstract: A film bulk acoustic resonator includes: a piezoelectric thin film that is formed on a principal surface of a substrate; and a lower electrode and an upper electrode that are arranged to sandwich the piezoelectric thin film. In this film bulk acoustic resonator, the piezoelectric thin film is made of aluminum nitride, and at least one of the lower electrode and the upper electrode contains a ruthenium or ruthenium-alloy layer.

Abstract: A thin-film piezo-resonator includes a silicon substrate and a resonator assembly. The substrate is formed with a cavity or through-hole which is opened in the upper and the lower surfaces of the substrate. The resonator assembly, disposed at a location corresponding to the cavity, is composed of a first electrode contacting the upper surface of the substrate, a piezoelectric layer formed on the first electrode and a second electrode formed on the piezoelectric layer. The cavity has a side surface extending in a substantially perpendicular direction to the first surface.

Abstract: A film bulk acoustic resonator is fabricated in the following manner. First, a base layer is formed on an insulating substrate. Then, a resonator assembly is formed on the base layer. The resonator assembly includes a first electrode held in contact with the base layer, a second electrode, and a piezoelectric layer held between the first and the second electrodes. Then, a resist layer is formed to cover the resonator assembly and the base layer. Then, a through-hole is formed in the resist layer so that the base layer is exposed via the through-hole. Then, etchant is supplied via the through-hole to make a space in the base layer under the resonator assembly. Finally, the resist layer is removed.

Abstract: An electrical contacting device includes a plurality of current paths connected in parallel to each other, and a plurality of electrical contact points each having a first contact and a second contact that are mechanically opened and closed. Each current path is provided with a corresponding one of the contact points. For prevention of the occurrence of arc discharge at the contact points, each current path has its electrical characteristics adjusted in order not to allow the passage of the minimum discharge current.

Abstract: A surface acoustic wave filter includes series-arm resonators and parallel-arm resonators that are connected in a ladder-like fashion.

Abstract: A filter device includes a filter element that has piezoelectric thin-film resonators arranged in series arms and parallel arms, and a package that houses the filter element in a face-down state. In this filter device, the filter element and the package are electrically connected to each other through bumps. The package includes first pad parts on which the bumps are placed, and transmission paths that electrically connect the first pad parts to the outside. The filter element includes second pad parts that are electrically connected to the first pad parts through the bumps, and wiring parts that electrically connect the second pads to the piezoelectric thin-film resonators and electrically connect the piezoelectric thin-film resonators to one another. In this structure, inductances formed with the transmission paths are connected in series to the piezoelectric thin-film resonators.

Abstract: A filter element includes resonators that are arranged in series arms and parallel arms in a circuit. In this filter element, at least one of the series-arm resonators includes a plurality of single-terminal pair piezoelectric thin-film resonators connected in parallel.

Abstract: A film bulk acoustic resonator is fabricated in the following manner. First, a base layer is formed on an insulating substrate. Then, a resonator assembly is formed on the base layer. The resonator assembly includes a first electrode held in contact with the base layer, a second electrode, and a piezoelectric layer held between the first and the second electrodes. Then, a resist layer is formed to cover the resonator assembly and the base layer. Then, a through-hole is formed in the resist layer so that the base layer is exposed via the through-hole. Then, etchant is supplied via the through-hole to make a space in the base layer under the resonator assembly. Finally, the resist layer is removed.

Abstract: A thin-film piezo-resonator includes a silicon substrate and a resonator assembly. The substrate is formed with a cavity or through-hole which is opened in the upper and the lower surfaces of the substrate. The resonator assembly, disposed at a location corresponding to the cavity, is composed of a first electrode contacting the upper surface of the substrate, a piezoelectric layer formed on the first electrode and a second electrode formed on the piezoelectric layer. The cavity has a side surface extending in a substantially perpendicular direction to the first surface.

Abstract: A filter chip includes multiple series-arm resonators arranged in series arms of a ladder arrangement, and multiple parallel-arm resonators arranged in parallel arms of the ladder arrangement. A common line is connected to first electrodes of at least two parallel-arm resonators among the multiple parallel-arm resonators. Second electrodes of said at least two parallel-arm resonators are connected to associated series-arm resonators among the multiple series-arm resonators.

Abstract: A tunable capacitor includes a substrate, a stationary electrode and a movable electrode supported by the substrate, piezoelectric actuators that are supported by the substrate and drive the movable electrode, and a dielectric layer interposed between the stationary electrode and the movable electrode.

Abstract: A thin-film piezo-resonator includes a silicon substrate and a resonator assembly. The substrate is formed with a cavity or through-hole which is opened in the upper and the lower surfaces of the substrate. The resonator assembly, disposed at a location corresponding to the cavity, is composed of a first electrode contacting the upper surface of the substrate, a piezoelectric layer formed on the first electrode and a second electrode formed on the piezoelectric layer. The cavity has a side surface extending in a substantially perpendicular direction to the first surface.