The invention relates to a piezoelectric resonator, which comprises a base and at least two vibrating arms (3) extending from the base, at least two grooves (4a, 4b) being formed opposite each other on part of the length of the arms and on upper and lower faces of the arms. The depth of the groove on the upper face is less than 30% of the total thickness of each arm and the depth of the groove on the lower face is more than 50% of the total thickness of each arm, or reversely.

A method for adjusting a resonant frequency of a resonator without impairing piezoelectricity that includes preparing a lower lid; arranging a substrate with a lower surface that faces the lower lid and forming a first electrode layer, a piezoelectric film, and a second electrode layer on an upper surface of the substrate. Moreover, a vibration arm is formed that bends and vibrates from the first electrode layer, the second electrode layer, and the piezoelectric film and an upper lid faces the lower lid with the resonator interposed therebetween. The method further includes adjusting a frequency of the resonator before or after arranging the upper lid by exciting the vibration arm by applying a voltage between the first electrode layer and the second electrode layer and by causing a part of the vibration arm to collide with either or both of the lower lid and the upper lid.

A vibrator element includes at least one vibrating arm with a weight provided thereto. The weight is provided with at least one processing scar. When an axis which overlaps a center in a width direction of the vibrating arm, and which extends along an extending direction of the vibrating arm is a central axis, and an axis which overlaps a centroid of the vibrating arm, and which extends along the extending direction of the vibrating arm is a centroid axis, the processing scar is formed in at least an area at the centroid axis side with respect to the central axis. S1>S2, where an area of the processing scar located at the centroid axis side with respect to the central axis is S1, and an area of the processing scar located at an opposite side to the centroid axis with respect to the central axis is S2.

There is provided a wafer making it possible to stably break off the piezoelectric vibrator element. The wafer includes a piezoelectric vibrator element, a frame part, and a connection part adapted to connect the piezoelectric vibrator element and the frame part to each other, and the connection part is provided with a guide part adapted to guide force, which is applied to the connection part from one surface side in the thickness direction of the connection part when breaking off the piezoelectric vibrator element from the frame part at the connection part, to at least one side in the width direction of the connection part.

An element is arranged to cooperate with another part so as to form an encapsulation device for a component including the element at least partially coated with a metallization. The metallization includes at least one metal layer protected by an intermetallic compound which is coated by a non-diffused portion of a material whose melting point is lower than 250 C. A method of fabricating the encapsulation device is also disclosed.

In a quartz crystal unit, the unit comprising a quartz crystal tuning fork resonator having a quartz crystal tuning fork base, and first and second quartz crystal tuning fork tines, each of the first and second quartz crystal tuning fork tines having a first vibrational portion including a first width and a second vibrational portion including a second width greater than the first width, at least one groove being formed in at least one of opposite main surfaces of the first vibrational portion of each quartz crystal tuning fork tine, the first width of the first vibrational portion of each quartz crystal tuning fork tine being greater than 0.03 mm and less than 0.075 mm and the second width of the second vibrational portion of each quartz crystal tuning fork tine being greater than 0.04 mm and less than 0.23 mm.

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.

In a quartz crystal unit, the unit comprising a case, a quartz crystal tuning fork resonator and a lid, the resonator having a tuning fork base, and first and second tuning fork tines, each of the first and second tuning fork tines having a first side surface and a second side surface opposite the first side surface, the first side surface of the first tuning fork tine confronting the second side surface of the second tuning fork tine; at least one groove having a plurality of surfaces including a first surface being formed in at least one of first and second main surfaces of each of the first and second tuning fork tines so that only the first surface of the at least one groove is directly opposite the first side surface of the corresponding tuning fork tine and a width of the at least one groove is greater than or equal to a distance in the width direction of the at least one groove measured from an outer edge of the at least one groove to an outer edge of the corresponding one of the first and second tuning fork tines and less than 0.07 mm.

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 vibrating arm of a vibrator element has a first surface, a second surface at an opposite side to the first surface in a Z direction, a first side surface and a second side surface as side surfaces, and a third side surface as a tip surface. At least one of the first side surface, the second side surface, and the third side surface includes a first side surface part tilted with respect to a Z direction, and a second side surface part tilted toward the first surface or the second surface with respect to the first side surface part. The first weight is arranged so that an outer edge of the first weight is located at inner side of innermost parts in the first side surface part and the second side surface part, or at the same position as the innermost parts when viewed from the Z direction.