A crystal oscillator (101) includes: a piezoelectric resonator plate (2) on which a first excitation electrode and a second excitation electrode are formed; a first sealing member (3) covering the first excitation electrode of the piezoelectric resonator plate (2); a second sealing member (4) covering the second excitation electrode of the piezoelectric resonator plate (2); and an internal space (13) formed by bonding the first sealing member (3) to the piezoelectric resonator plate (2) and by bonding the second sealing member (4) to the piezoelectric resonator plate (2), so as to hermetically seal a vibrating part including the first excitation electrode and the second excitation electrode of the piezoelectric resonator plate (2). An electrode pattern (371) including a mounting pad for wire bonding is formed on an outer surface (first main surface (311)) of the first sealing member (3).

A resonance device that includes a MEMS substrate including a resonator having a vibrating portion, a holding portion configured to hold the vibrating portion, and an isolation groove that surrounds the vibrating portion in a plan view of the resonance device; and an upper lid facing the MEMS substrate with the resonator interposed therebetween and that includes a connection wiring electrically connected to the vibrating portion.

A MEMS device is provided that includes a piezoelectric film, a first electrode and a second electrode sandwiching the piezoelectric film, a protective film that covers at least part of the second electrode and having a cavity that opens part of the second electrode, a third electrode that contacts the second electrode at least in the cavity and is provided so as to cover at least part of the protective film, and a first wiring layer having a first contact portion in contact with the third electrode.

A vibration element includes a base and a vibrating arm extending from the base. The vibrating arm includes an arm positioned between the base and a weight. A weight film is disposed on the weight. The weight has a first principal surface and a second principal surface in a front and back relationship with respect to a center plane of the arm. A center of gravity of the weight is located between the first principal surface and the center plane of the arm. A center of gravity of the weight film is located between the second principal surface and the center plane of the arm.

A vibrator device includes: a base having a first surface and a second surface in a front-back relationship with each other; a circuit element located at a first surface side of the base and having a third surface at the first surface side and a fourth surface in a front-back relationship with the third surface; a vibrator element located at a fourth surface side of the circuit element; a first bonding member that bonds the base to the circuit element; a second bonding member that bonds the circuit element to the vibrator element; and a lid bonded to the base so as to form a cavity that accommodates the circuit element and the vibrator element between the lid and the base, in which at least a part of the second bonding member overlaps the first bonding member in a plan view of the circuit element.

A quartz crystal resonator unit including a quartz crystal resonator having a quartz crystal blank, a frame surrounding an outer periphery of the quartz crystal blank, and coupling members connecting the frame to the quartz crystal blank. Moreover, a lid member and a base member are attached to the frame and seal the resonator. One or more outer electrodes is formed over end surfaces of the frame, the lid member, and the base member on a side where the coupling members are coupled. The one or more outer electrodes has a machinery quality factor smaller than that of the frame.

A piezoelectric bulk wave device that includes a piezoelectric thin plate that is made of LiTaO.sub.3, and first and second electrodes that are provided in contact with the piezoelectric thin plate. The piezoelectric bulk wave device utilizes the thickness shear mode of the piezoelectric thin plate made of LiTaO.sub.3. The first and second electrodes are each formed by a conductor having a specific acoustic impedance higher than the specific acoustic impedance of a transversal wave that propagates in LiTaO.sub.3. When the sum of the film thicknesses of the first and second electrodes is defined as an electrode thickness, and the thickness of the piezoelectric thin plate made of LiTaO.sub.3 is defined as an LT thickness, the electrode thickness/(electrode thickness+LT thickness) is not less than 5% and not more than 40%.

A microelectromechanical resonator includes a support structure, a resonator element suspended to the support structure, and an actuator for exciting the resonator element to a resonance mode. The resonator element includes a plurality of adjacent sub-elements each having a length and a width and a length-to-width aspect ratio of higher than 1 and being adapted to a resonate in a length-extensional, torsional or flexural resonance mode. Further, each of the sub-elements is coupled to at least one other sub-element by one or more connection elements coupled to non-nodal points of the of said resonance modes of the sub-elements for exciting the resonator element into a collective resonance mode.

A piezoelectric film that includes crystalline AlN; at least one first element partially replacing Al in the crystalline AlN; and a second element doping the crystalline AlN and which has an ionic radius smaller than that of the first element and larger than that of Al.

A piezoelectric bulk wave device that includes a piezoelectric thin plate that is made of LiTaO.sub.3, and first and second electrodes that are provided in contact with the piezoelectric thin plate. The piezoelectric bulk wave device utilizes the thickness shear mode of the piezoelectric thin plate made of LiTaO.sub.3, and of the Euler Angles (φ, θ, φ) of LiTaO.sub.3, φ is 0°, and θ is in the range of not less than 54° and not more than 107°.