A method for manufacturing a ceramic substrate that includes forming a mother multilayer body by positioning a hole in at least one ceramic green sheet among a plurality of laminated ceramic green sheets in a location that does not overlap with a recess formation-planned region in which a recess is to be formed after firing of the mother multilayer body and that overlaps with a singulation-planned line for singulating the mother multilayer body into pieces after firing; and forming the recess in the mother multilayer body before firing by performing press working on the recess formation-planned region of the mother multilayer body.

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.

A rectangular quartz crystal blank having long sides substantially parallel to a Z axis of the quartz crystal blank, and short sides substantially parallel to an X axis of the quartz crystal blank. The quartz crystal blank includes a first center region, a second region and a third region that are adjacent to the first region along a long-side direction, and a fourth region and a fifth region that are adjacent to the first region along a short-side direction. A thickness of the second region and a thickness of the third region are smaller than a thickness of the first region, and/or a thickness of the fourth region and a thickness of the fifth region are smaller than the thickness of the first region, and 19.87W/T20.36, where W is a length of a short side and T is a thickness.

A piezoelectric resonator unit that includes a piezoelectric resonator, a substrate including a protruding portion, and a cap joined to the protruding portion. The piezoelectric resonator unit has a first relation of W1+T1w1<W1+2T1, where, in a long-side sectional view, w1 is a width of an inside of an opening in the cap, T1 is a width of the protruding portion, and W1 is a width of the upper surface of the substrate between parts of the protruding portion; and has a second relation of W2+T2w2<W2+2T2, where, in a short-side sectional view, w2 is a width of the inside of the opening in the cap, T2 is a width of the protruding portion, and W2 is a width of the upper surface of the substrate between parts of the protruding portion.

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.

A composite substrate 10 is formed by bonding together a piezoelectric substrate 12 and a support substrate 14 that has a lower thermal expansion coefficient than the piezoelectric substrate. The support substrate 14 is formed by directly bonding together a first substrate 14a and a second substrate 14b at a strength that allows separation with a blade, the first and second substrates being formed of the same material, and a surface of the first substrate 14a is bonded to the piezoelectric substrate 12, the surface being opposite to another surface of the first substrate 14a bonded to the second substrate 14b.

An AT-cut crystal element is provided for reducing unnecessary vibration and for improving impedance of a resonator. Two side surfaces intersecting with a Z-axis of a crystallographic axis of crystal are constituted of three surfaces of a first surface as an m-surface of quartz crystal, a second surface that intersects with the first surface and is other than the m-surface, and a third surface that intersects with the second surface and is other than the m-surface. Moreover, the second surface is a surface corresponding to a surface obtained by rotating a principal surface of the AT-cut crystal element by 743 having an X-axis of crystal as a rotation axis, and the third surface is a surface corresponding to a surface obtained by rotating the principal surface by 563 having the X-axis of the crystal as the rotation axis.

A composite substrate 10 is formed by bonding together a piezoelectric substrate 12 and a support substrate 14 that has a lower thermal expansion coefficient than the piezoelectric substrate. The support substrate 14 is formed by directly bonding together a first substrate 14a and a second substrate 14b at a strength that allows separation with a blade, the first and second substrates being formed of the same material, and a surface of the first substrate 14a is bonded to the piezoelectric substrate 12, the surface being opposite to another surface of the first substrate 14a bonded to the second substrate 14b.

A method of manufacturing a piezoelectric resonator unit that includes mounting a piezoelectric resonator on a base member, the piezoelectric resonator including a piezoelectric element and a pair of excitation electrodes facing each other with the piezoelectric element interposed therebetween, each of the pair of excitation electrodes including an underlying layer containing chromium and a surface layer on the underlying layer; forming chromium oxide on the surface layer of each of the pair of excitation electrodes by oxidizing chromium diffused from the underlying layer such that an amount of the chromium oxide is larger on the surface layer of the excitation electrode on a base member side than on the surface layer of the excitation electrode on a lid member side among the pair of excitation electrodes; and joining a lid member to the base member such that the piezoelectric resonator is between the base member and the lid member.

A piezoelectric resonator device having a sandwich structure is provided, which is capable of improving reliability while ensuring hermeticity of the internal space in which a vibrating part of the piezoelectric resonator plate is sealed. A crystal resonator 101 includes: a crystal resonator plate 2; a first sealing member 3 covering a first excitation electrode 221 of the crystal resonator plate 2; and a second sealing member 4 covering a second excitation electrode 222 of the crystal resonator plate 2. A third through hole 269 is formed in the crystal resonator plate 2 to penetrate between a first main surface 211 and a second main surface 212. A through electrode 71 of the third through hole 269 is conducted to the first excitation electrode 221. A seventh through hole 350 is formed in the first sealing member 3 to penetrate between a first main surface 311 and a second main surface 312. The through electrode 71 of the third through hole 269 is conducted to the through electrode 71 of the seventh through hole 350. The third through hole 269 is not superimposed to the seventh through hole 350 in plan view.