In a piezoelectric resonator device according to an embodiment, an internal space is formed by bonding a first sealing member to a crystal resonator plate and bonding a second sealing member to the crystal resonator plate. The internal space hermetically seals a vibrating part including a first excitation electrode and a second excitation electrode of the crystal resonator plate. Seal paths that hermetically seal the vibrating part of the crystal resonator plate are formed to have an annular shape in plan view. A plurality of external electrode terminals is formed on a second main surface of the second sealing member to be electrically connected to an external circuit board. The external electrode terminals are respectively disposed on and along an external frame part surrounding the internal space in plan view.

A single-chamber-type temperature-sensor-provided crystal unit includes: a single chamber; and a quartz-crystal vibrating piece and a temperature sensor, provided in the single chamber. The quartz-crystal vibrating piece has a square planar shape. The quartz-crystal vibrating piece is secured in the single chamber at two securing portions via conductive members. The two securing portions are in proximities of both ends of a first side of the quartz-crystal vibrating piece. The temperature sensor has a rectangular parallelepiped shape. The temperature sensor is disposed such that a longitudinal surface of the temperature sensor is parallel to a line segment Y and the temperature sensor is close to a side of the two securing portions within the single chamber, when a line segment connecting the two securing portions is defined as the line segment Y.

A resonance element supported by a bearing structure includes a crystal chip and an excitation electrode. The crystal chip includes a main surface having a support surface portion being in contact with the bearing structure. The excitation electrode is disposed on the main surface, has an electrode area, and includes an electrode indentation boundary partly encompassing the support surface portion. The electrode indentation boundary has a first boundary end and a second boundary end being opposite to the first boundary end. The electrode indentation boundary and a reference line segment defined by the first and the second boundary ends form an electrode indentation region having an indentation area. A ratio of the indentation area to the electrode area ranges from 0.05 to 0.2.

The disclosed technology generally relates to quartz crystal devices and more particularly to quartz crystal devices configured to vibrate in torsional mode. In one aspect, a quartz crystal device configured for temperature sensing comprises a fork-shaped quartz crystal comprising a pair of elongate tines laterally extending from a base region in a horizontal lengthwise direction of the fork-shaped quartz crystal. Each of the tines has formed on one or both of opposing sides thereof a vertically protruding line structure laterally elongated in the horizontal lengthwise direction. The quartz crystal device further comprises a first electrode and a second electrode formed on the one or both of the opposing sides of each of the tines and configured such that, when an electrical bias is applied between the first and second electrodes, the fork-shaped quartz crystal vibrates in a torsional mode in which each of the tines twists about a respective axis extending in the horizontal lengthwise direction.

The disclosed technology generally relates to quartz crystal devices and more particularly to quartz crystal devices configured to vibrate in torsional mode. In one aspect, a quartz crystal device configured for temperature sensing comprises a fork-shaped quartz crystal comprising a pair of elongate tines laterally extending from a base region in a horizontal lengthwise direction of the fork-shaped quartz crystal, wherein each of the tines has formed on one or both of opposing sides thereof a pair of vertically recessed groove structures laterally elongated in the horizontal lengthwise direction, wherein the pair of groove structures are separated in a horizontal widthwise direction by a line structure. The quartz crystal device further comprises a first electrode and a second electrode formed on the one or both of the opposing sides of each of the tines and configured such that, when an electrical bias is applied between the first and second electrodes, the fork-shaped quartz crystal vibrates in a torsional mode in which each of the tines twists about a respective axis extending in the horizontal lengthwise direction.

The disclosed technology generally relates to quartz crystal devices and more particularly to quartz crystal devices configured to vibrate in torsional mode. In one aspect, a quartz crystal device configured for temperature sensing comprises a fork-shaped quartz crystal comprising a pair of elongate tines laterally extending from a base region in a horizontal lengthwise direction of the fork-shaped quartz crystal. Each of the tines has formed on one or both of opposing sides thereof a vertically protruding line structure laterally elongated in the horizontal lengthwise direction. The quartz crystal device further comprises a first electrode and a second electrode formed on the one or both of the opposing sides of each of the tines and configured such that, when an electrical bias is applied between the first and second electrodes, the fork-shaped quartz crystal vibrates in a torsional mode in which each of the tines twists about a respective axis extending in the horizontal lengthwise direction.

The vibration substrate having a main surface extending parallel to a first direction and a second direction that are orthogonal to each other, and that includes a main body region having a vibrating portion at least in a part thereof and at least one holding region arranged side by side with the main body region along the first direction. The at least one holding region including a holding portion and a beam portion connecting the holding portion and the main body region. The beam portion includes a first arm portion extending from the holding portion along the first direction, a second arm portion extending along the second direction from an end portion of the first arm portion on a side thereof opposite to the holding portion, and a connection portion connecting the second arm portion and the main body region.

A piezoelectric device includes a container and an AT-cut crystal element. The AT-cut crystal element has at least one side surface intersecting with a Z′-axis of the crystallographic axis of the crystal constituted of three surfaces. The first surface is a surface equivalent to a surface formed by rotating the principal surface by 4°±3.5° with an X-axis of the crystal as a rotation axis. The second surface is a surface equivalent to a surface formed by rotating the principal surface by −57°±5° with the X-axis. The third surface is a surface equivalent to a surface formed by rotating the principal surface by −42°±5° with the X-axis. When two corner portions on a side of a second side opposed to the first side of the AT-cut crystal element are viewed in plan view, each of the two corner portions have an approximately right angle.

In a crystal resonator plate (2), a support part (24) extends from only one corner part positioned in the +X direction and in the −Z′ direction of a vibrating part (22) to an external frame part (23) in the −Z′ direction. The vibrating part (22) and at least part of the support part (24) form an etching region (Eg) having a thickness thinner than a thickness of the external frame part (23). A stepped part is formed at a boundary of the etching region (Eg), and a first lead-out wiring (223) is formed over the support part (24) to the external frame part (23) so as to overlap with the stepped part. At least part of the stepped part that is superimposed on the first lead-out wiring (223) is formed so as not to be parallel to the X axis in plan view.

A resonance element supported by a bearing structure includes a crystal chip and an excitation electrode. The crystal chip includes a main surface having a support surface portion being in contact with the bearing structure. The excitation electrode is disposed on the main surface, has an electrode area, and includes an electrode indentation boundary partly encompassing the support surface portion. The electrode indentation boundary has a first boundary end and a second boundary end being opposite to the first boundary end. The electrode indentation boundary and a reference line segment defined by the first and the second boundary ends form an electrode indentation region having an indentation area. A ratio of the indentation area to the electrode area ranges from 0.05 to 0.2.