A crystal oscillator includes: a crystal resonator plate having a first excitation electrode and a second excitation electrode. A first sealing member covers the first excitation electrode of the crystal resonator plate. A second sealing member covers the second excitation electrode of the crystal resonator plate. An internal space is formed by bonding the first sealing member to the crystal resonator plate and the second sealing member to the crystal resonator plate, and seals a vibrating part of the crystal resonator plate. First and second shield electrodes are connected to a fixed potential (e.g. GND potential) in the internal space.

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 element includes: a base; an arm that is made of silicon and continuous with the base; a silicon dioxide layer arranged on the arm and a continuous portion in which the arm and the base are continuous; a zirconium dioxide layer arranged on the silicon dioxide layer at least in the continuous portion; a first electrode arranged on the zirconium dioxide layer; a piezoelectric layer arranged on the first electrode; and a second electrode arranged on the piezoelectric layer.

A crystal vibration element that includes a crystal piece that has a prescribed crystal orientation, and a first direction and a second direction in a plan view thereof; and excitation electrodes that are respectively provided on front and rear surfaces of the crystal piece in order to excite a thickness shear vibration in the crystal piece upon application of an alternating electric field. A vibration distribution of the crystal piece has a vibration region that extends in a band-like shape in the second direction of the crystal piece and non-vibration regions that are adjacent to opposed sides of the vibration region in the first direction of the crystal piece.

A vibrator that includes a silicon substrate, an electrode facing a surface of the silicon substrate, and a piezoelectric body between the silicon substrate and the electrode and that produces contour vibration in a plane along the surface of the silicon substrate in accordance with a voltage applied to the electrode. The vibrator includes one or more substantially rectangular vibration regions each having a long side parallel to a node of the contour vibration of the piezoelectric body and a short side orthogonal to the node of the contour vibration of the piezoelectric body and corresponding to a half-wavelength of the contour vibration. The resonator satisfies W/T≥4 and y=−0.85×(1/T)+0.57±0.05 where T is the thickness of the silicon substrate, W is the width of the short side of the vibration region, and y is the resistivity of the silicon substrate.

A quartz crystal resonator is provided that includes a body portion with first and second main surfaces facing each other and, in plan view has a pair of long sides extending in a first direction and a pair of short sides extending in a second intersecting direction. Moreover, first and second excitation electrodes are disposed on the first and second main surfaces respectively; a frame surrounds the body portion at both ends and is separated from the both ends; and first and second coupling portions extend from the short sides in the first direction with widths of the short sides. At least one of the first and second coupling portions has a portion whose thickness in a third direction is smaller than a thickness in the third direction of a region of the body portion where the first excitation electrode and the second excitation electrode face each other.

A method of forming a quartz crystal resonator is provided with the resonator including a body portion with first and second main surfaces facing each other and, in plan view having a pair of long sides extending in a first direction and a pair of short sides extending in a second intersecting direction. Moreover, first and second excitation electrodes are formed on the respective main surfaces; a frame surrounds the body portion at both ends and is separated from the both ends; and first and second coupling portions extend from the short sides and with widths of the short sides. At least one of the first and second coupling portions is formed with a thickness in a third direction is smaller than a thickness in the third direction of a region of the body portion where the first excitation electrode and the second excitation electrode face each other.

A crystal vibration element that includes a crystal piece that has a prescribed crystal orientation, and a first direction and a second direction in a plan view thereof; and excitation electrodes that are respectively provided on front and rear surfaces of the crystal piece in order to excite a thickness shear vibration in the crystal piece upon application of an alternating electric field. A vibration distribution of the crystal piece has a vibration region that extends in a band-like shape in the second direction of the crystal piece and non-vibration regions that are adjacent to opposed sides of the vibration region in the first direction of the crystal piece.

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.

A crystal vibration element that includes a crystal piece that has a prescribed crystal orientation, and a first direction and a second direction in a plan view thereof; and excitation electrodes that are respectively provided on front and rear surfaces of the crystal piece in order to excite a thickness shear vibration in the crystal piece upon application of an alternating electric field. A vibration distribution of the crystal piece has a vibration region that extends in a band-like shape in the second direction of the crystal piece and non-vibration regions that are adjacent to opposed sides of the vibration region in the first direction of the crystal piece.