Flexural resonator element and flexural resonator for reducing energy loss due to heat dissipation

1. A flexural resonator element, comprising:

a base body; and

a beam with a groove and a through-hole, the beam being extended in a Y direction from the base body and flexurally vibrating in an X direction orthogonal to the Y direction,

the groove being formed on a surface of the beam perpendicular to a Z direction orthogonal to the X direction and the Y direction, the groove formed on the surface of the beam includes two grooves, each of the two grooves is formed on a different one of two surfaces of the beam perpendicular to the Z direction, each of the two grooves is formed adjacent to the other groove such that the grooves do not overlap in plan view, and

the through-hole having a smaller width in the X direction than a width of an opening of the groove in the X direction and penetrating from an inner surface of the groove formed on the surface of the beam to a surface of the beam opposite to the surface of the beam having the groove.

2. The flexural resonator element according to claim 1 , wherein the through-hole includes a plurality of through-holes, the plurality of through-holes being formed in the groove.

3. The flexural resonator element according to claim 1 , wherein the through-hole penetrates from the inner surface of the groove formed on one of the two surfaces of the beam to the inner surface of the groove formed on an other one of the two surfaces of the beam.

4. The flexural resonator element according to claim 1 , wherein the beam includes a first electrode provided on the inner surface of the groove, a second electrode provided on a surface of the beam perpendicular to the X direction, and a plug provided on an inner surface of the through-hole.

5. The flexural resonator element according to claim 1 , wherein the base body and the beam are made of quartz crystal.

6. The flexural resonator element according to claim 1 , wherein the flexural resonator element is of a tuning fork type in which the beam includes two cantilevered beams extended in parallel to each other from the base body.

7. The flexural resonator element according to claim 1 , wherein the base body includes a base portion and a pair of connecting portions extended from the base portion in directions opposite to each other, and the beam includes a pair of detection beams extended from the base portion in directions opposite to each other and two pairs of driving beams extended from the connecting portion in directions opposite to each other.

8. The flexural resonator element according to claim 1 , wherein the flexural resonator element is of a double-ended tuning fork type in which the base body includes two base bodies, the beam includes two beams formed in parallel to each other, opposite ends of each of the two beams being supported by the two base bodies, and the groove formed on the each beam includes four grooves, each two of the four grooves being formed on a different one of the two surfaces of the beam perpendicular to the Z direction.

9. The flexural resonator element according to claim 8 , wherein, in the flexural resonator element of the double-ended tuning fork type, the base bodies form a frame-shaped portion having an opening portion formed within the frame-shaped portion, and the two beams are formed in parallel to each other in the opening portion, the opposite ends of each of the beams being supported by the frame-shaped portion of the base bodies.

10. The flexural resonator element according to claim 8 , wherein the each two grooves formed on the different one of the two surfaces of the beam are oriented in mutually opposite directions, and the through-hole penetrates from the inner surface of each of the grooves formed on one of the two surfaces to the inner surface of each of the grooves formed on an other one of the surfaces.

11. A flexural resonator, comprising:

the flexural resonator element of claim 1 ;

a casing housing the flexural resonator element; and

a cover sealing the casing.

12. The flexural resonator element according to claim 1 , wherein each of the two grooves extends through the beam in the Z direction toward the different one of the two surfaces, and

the through-hole passes continuously through the beam from the inner surface of the groove to the different one of the two surfaces.