An oscillator includes a package having a plurality of external terminals disposed on a mounting surface, a circuit element housed in the package, and a resonator which is housed in the package, and is electrically coupled to the circuit element, wherein the circuit element is electrically coupled to the package with a plurality of pads each of which is bonded to the package via a bump member, the circuit element has a rectangular shape in a plan view, and at least three of closest ones to four corners of the circuit element out of the bump members are bonded to the package at respective positions overlapping the plurality of external terminals in the plan view.

There is configured an oscillator characterized by including an outer package having a housing space, an inner package housed in the housing space, a resonator element housed in the inner package, a heater element housed in the housing space, and fixed to the inner package, an oscillation circuit configured to oscillate the resonator element, a conducting member configured to electrically couple the inner package and the heater element to each other, and a first bonding wire configured to couple the heater element and the outer package to each other, and configured to electrically couple the conducting member and the outer package to each other.

A vibration device includes a base including a semiconductor substrate and a through electrode passing through the portion between a first surface and a second surface of the semiconductor substrate, a vibrator placed at the side facing the first surface, and an external connection terminal provided at the side facing the second surface via an insulating layer. An oscillation circuit that is electrically coupled to the vibrator via the through electrode and generates an oscillation signal by causing the vibrator to oscillate, and an output buffer circuit that outputs a clock signal based on the oscillation signal are placed at the second surface. The clock signal from the output buffer circuit is outputted via the external connection terminal. The through electrode and the external connection terminal are arranged so as not to overlap with each other in a plan view viewed in the direction perpendicular to the first surface.

A vibration device includes a base including a semiconductor substrate and a through electrode passing through the portion between a first surface and a second surface of the semiconductor substrate, a vibrator placed at the side facing the first surface, and an external connection terminal provided at the side facing the second surface via an insulating layer. An oscillation circuit that is electrically coupled to the vibrator via the through electrode and generates an oscillation signal by causing the vibrator to oscillate, and an output buffer circuit that outputs a clock signal based on the oscillation signal are placed at the second surface. The clock signal from the output buffer circuit is outputted via the external connection terminal. The through electrode and the external connection terminal are arranged so as not to overlap with each other in a plan view viewed in the direction perpendicular to the first surface.

An acoustic wave device includes a support including a support substrate, a piezoelectric layer on the support, and an excitation electrode on the piezoelectric layer. A hollow portion is provided in the support and overlaps with at least a portion of the excitation electrode in plan view. The support includes a cavity opening on a side of the piezoelectric layer, and an inner wall surface connected to the cavity and facing the hollow portion. A functional film is provided on at least a portion of the inner wall surface and has an electromagnetic-wave absorption capacity in a wavelength range from about 0.2 .Math.m to about 1.2 .Math.m inclusive.

A quartz crystal resonator that includes an AT-cut quartz crystal blank including a first main surface and a second main surface that face each other and each of which has long sides extending in an X-axis direction of the quartz crystal blank and short sides extending in a Z′-axis direction of the quartz crystal blank, and a first side surface and a second side surface that are located adjacent to the long sides of the first main surface and the second main surface; a first excitation electrode and a second excitation electrode; and an extension electrode that extends from the first main surface to the second main surface along the first side surface and that is electrically connected to the first excitation electrode. Each the first and second side surfaces have a first m-plane face and a second m-plane face.

A quartz crystal resonator that includes an AT-cut quartz crystal blank including a first main surface and a second main surface that face each other and each of which has long sides extending in an X-axis direction of the quartz crystal blank and short sides extending in a Z′-axis direction of the quartz crystal blank, and a first side surface and a second side surface that are located adjacent to the long sides of the first main surface and the second main surface; a first excitation electrode and a second excitation electrode; and an extension electrode that extends from the first main surface to the second main surface along the first side surface and that is electrically connected to the first excitation electrode. Each the first and second side surfaces have a first m-plane face and a second m-plane face.

An AT-cut crystal resonator plate includes: a vibrating part having a rectangular shape in plan view that is disposed on a center of the AT-cut crystal resonator plate and that has excitation electrodes respectively formed on a first and a second main surfaces; a cut-out part having a rectangular shape in plan view that is formed along an outer periphery of the vibrating part; an external frame part having a rectangular shape in plan view that is formed along an outer periphery of the cut-out part; and a connecting part that connects the vibrating part to the external frame part and that extends, in a Z′ axis direction of the vibrating part, from one end part of a side of the vibrating part along an X axis direction. The connecting part includes wide parts whose widths gradually increase only toward the external frame part.

An AT-cut crystal resonator plate includes: a vibrating part having a rectangular shape in plan view that is disposed on a center of the AT-cut crystal resonator plate and that has excitation electrodes respectively formed on a first and a second main surfaces; a cut-out part having a rectangular shape in plan view that is formed along an outer periphery of the vibrating part; an external frame part having a rectangular shape in plan view that is formed along an outer periphery of the cut-out part; and a connecting part that connects the vibrating part to the external frame part and that extends, in a Z′ axis direction of the vibrating part, from one end part of a side of the vibrating part along an X axis direction. The connecting part includes wide parts whose widths gradually increase only toward the external frame part.

In a crystal oscillator, a crystal resonator and an IC chip are hermetically sealed in a package. The crystal resonator includes: a crystal resonator plate including a first excitation electrode formed on a first main surface, and a second excitation electrode, which makes a pair with the first excitation electrode, formed on a second main surface; a first sealing member covering the first excitation electrode of the crystal resonator plate; and a second sealing member covering the second excitation electrode of the crystal resonator plate. A vibrating part including the first excitation electrode and the second excitation electrode of the crystal resonator plate is hermetically sealed by bonding the first sealing member to the crystal resonator plate, and the second sealing member to the crystal resonator plate.