Piezoelectric oscillator

Abstract

A piezoelectric oscillator (1) comprises: a piezoelectric oscillation element (10) that has an oscillating part (110), a holding part (120) which is provided at a distance from the oscillating part (110) in at least a part of a frame-shaped region surrounding the oscillating part (110), and a supporting arm (130) which connects the oscillating part (110) with the holding part (120) and supports the oscillating part (110); a first substrate (20) that is provided so as to face the piezoelectric oscillation element (10); a second substrate (30) that is provided so as to face the piezoelectric oscillation element (10) on the opposite side from the first substrate (20); a first joining part (40) that joins the holding part (120) of the piezoelectric oscillation element (10) and the first substrate (20) together; a second joining part (50) that joins the holding part (120) of the piezoelectric oscillation element (10) and the second substrate (30) together; and reinforcing parts (60, 70) that cover at least a part of the supporting arm (130) and that are made of resin.

Description

Piezoelectric vibrator

[0001] The present invention relates to a piezoelectric vibrator.

[0002] Piezoelectric vibrators are used as timing devices, sensors, oscillators, etc. in various electronic devices such as mobile communication terminals, communication base stations, and home appliances. A piezoelectric vibrator includes a sealed piezoelectric vibration element, and the piezoelectric vibration element includes a piezoelectric substrate having a pair of main surfaces and a pair of excitation electrodes provided on the pair of main surfaces of the piezoelectric substrate.

[0003] For example, Patent Document 1 discloses a piezoelectric device including a piezoelectric vibrating piece, a lid portion, and a base portion that sandwich the piezoelectric vibrating piece. The piezoelectric vibrating piece has a vibrating portion, a frame portion that surrounds the vibrating portion, and a connecting portion that connects the vibrating portion and the frame portion. The vibrating portion is provided with an excitation electrode, the frame portion is provided with a connection electrode, and the connecting portion is provided with an extraction electrode.

[0004] JP 2014-176071 A

[0005] In the piezoelectric device described in Patent Document 1, when an impact such as a drop or vibration is applied, stress is concentrated at the connection portion between the frame portion and the connecting portion, which may damage the piezoelectric vibrating reed.

[0006] The present invention has been made in view of the above circumstances, and has as its object to provide a piezoelectric vibrator that can improve reliability.

[0007] A piezoelectric vibrator according to one aspect of the present invention comprises a piezoelectric vibration element having a vibration portion, a holding portion provided in at least a part of a frame-shaped region surrounding the vibration portion at a distance from the vibration portion, and a support arm connecting the vibration portion and the holding portion to support the vibration portion, a first substrate provided opposite the piezoelectric vibration element, a second substrate provided opposite the piezoelectric vibration element on the opposite side of the first substrate, a first bonding portion joining the holding portion of the piezoelectric vibration element to the first substrate, a second bonding portion joining the holding portion of the piezoelectric vibration element to the second substrate, and a reinforcing portion made of resin covering at least a part of the support arm.

[0008] According to the present invention, it is possible to provide a piezoelectric vibrator that can improve reliability.

[0009] 1 is an exploded perspective view of a quartz crystal resonator according to a first embodiment; 2 is a cross-sectional view taken along line II-II of the quartz crystal resonator according to the first embodiment; 3 is a cross-sectional view taken along line III-III of the quartz crystal resonator according to the first embodiment; 4 is a plan view of a quartz crystal resonator according to the first embodiment; 5 is a plan view of a quartz crystal resonator element according to the first embodiment; 6 is a plan view of a lower cover according to the first embodiment; 7 is a cross-sectional view of a quartz crystal resonator according to a second embodiment; 8 is a cross-sectional view of a quartz crystal resonator according to a third embodiment; 9 is a plan view of a quartz crystal resonator according to the third embodiment; 10 is a cross-sectional view of a quartz crystal resonator according to a fourth embodiment; 11 is a cross-sectional view of a quartz crystal resonator according to a fifth embodiment; 12 is a plan view of a quartz crystal resonator according to the fifth embodiment; 13 is a cross-sectional view of a quartz crystal resonator according to a sixth embodiment; 14 is a plan view of a lower cover according to the sixth embodiment.

[0010] Hereinafter, embodiments of the present invention will be described. In the following description of the drawings, the same or similar components are denoted by the same or similar reference numerals. The drawings are illustrative, and the dimensions and shapes of each part are schematic. The technical scope of the present invention should not be interpreted as being limited to the embodiments.

[0011] For the sake of clarity, each drawing may be accompanied by a Cartesian coordinate system consisting of an X-axis, a Y'-axis, and a Z'-axis to clarify the relationship between the drawings and to aid in understanding the positional relationship of each component. The X-axis, Y'-axis, and Z'-axis correspond to each other in each drawing. The X-axis, Y'-axis, and Z'-axis each correspond to the crystalline axes of the quartz substrate 11, which will be described later. The X-axis corresponds to the electrical axis (polarity axis) of the quartz, the Y-axis corresponds to the mechanical axis of the quartz, and the Z-axis corresponds to the optical axis of the quartz. The Y'-axis and Z'-axis are axes obtained by rotating the Y-axis and Z-axis counterclockwise around the X-axis by θ degrees when viewed from the positive direction of the X-axis.

[0012] In the following description, the direction parallel to the X-axis is referred to as the "X-axis direction," the direction parallel to the Y'-axis is referred to as the "Y'-axis direction," and the direction parallel to the Z'-axis is referred to as the "Z'-axis direction." The directions of the arrows on the X-axis, Y'-axis, and Z'-axis are referred to as "positive" or "+ (plus)," and the directions opposite the arrows are referred to as "negative" or "- (minus)." For convenience, the +Y'-axis direction will be described as the upward direction, and the -Y'-axis direction will be described as the downward direction, but the up-down orientation of the quartz crystal vibrating element 10 and the quartz crystal vibrator 1 is not limited to this. The plane specified by the X-axis and Z'-axis will be referred to as the Z'X plane, and the same applies to planes specified by the other axes.

[0013] First Embodiment First, the configuration of a quartz crystal resonator according to the first embodiment will be described with reference to FIGS. 1 to 6. FIG. 1 is an exploded perspective view of the quartz crystal resonator according to the first embodiment. FIG. 2 is a cross-sectional view taken along line II-II of the quartz crystal resonator shown in the first embodiment. FIG. 3 is a cross-sectional view taken along line III-III of the quartz crystal resonator shown in the first embodiment. FIG. 4 is a plan view of the quartz crystal resonator according to the first embodiment. FIG. 5 is a plan view of the quartz crystal resonator element according to the first embodiment. FIG. 6 is a plan view of the lower cover according to the first embodiment.

[0014] Fig. 2 is a cross-sectional view of the quartz crystal unit 1 in the XY' plane, showing a cross-sectional structure passing through the center of a vibrating unit 110 (described later). Fig. 3 is a cross-sectional view of the quartz crystal unit 1 in the Y'Z' plane, showing a cross-sectional structure passing through a connection portion 132 of a support arm 130 with a holding unit 120 (described later).

[0015] The quartz crystal resonator 1 includes a quartz crystal resonator element 10, a lower cover 20, an upper cover 30, a lower bonding portion 40, an upper bonding portion 50, a lower reinforcing portion 60, and an upper reinforcing portion 70. The lower cover 20, the quartz crystal resonator element 10, and the upper cover 30 are arranged in this order with a gap in the Y'-axis direction. Hereinafter, the Y'-axis direction in which the lower cover 20, the quartz crystal resonator element 10, and the upper cover 30 are stacked will be referred to as the "thickness direction." The upper cover 30 corresponds to an example of a first substrate, and the lower cover 20 corresponds to an example of a second substrate. The upper bonding portion 50 corresponds to an example of a first bonding portion, and the lower bonding portion 40 corresponds to an example of a second bonding portion. The upper reinforcing portion 70 corresponds to an example of a first reinforcing portion, and the lower reinforcing portion 60 corresponds to an example of a second reinforcing portion.

[0016] The crystal resonator 1 is used as a component of, for example, a temperature compensated crystal oscillator (TCXO), a voltage controlled crystal oscillator (VCXO), or an oven controlled crystal oscillator (OCXO).

[0017] The quartz crystal vibrating element 10 is an electromechanical energy conversion element that converts electrical energy into mechanical energy and vice versa by the piezoelectric effect. As shown in FIG. 1, the quartz crystal vibrating element 10 has a vibrating portion 110, a holding portion 120, and a support arm 130.

[0018] The vibrating unit 110 is excited at a predetermined frequency based on the applied alternating voltage. The vibrating unit 110 is held so as to be vibrable in a vibration space provided between the lower cover 20 and the upper cover 30. The main vibration of the vibrating unit 110 is a thickness shear vibration mode.

[0019] As shown in FIG. 5 , the shape of the vibration section 110 when viewed in a plane along the XZ′ plane (hereinafter simply referred to as “planar view”) (hereinafter referred to as “planar shape”) is rectangular. The vibration section 110 has a pair of short sides 111A and 111B and a pair of long sides 111C and 111D. The pair of short sides 111A and 111B extend along the Z′ axis direction and face each other in the X axis direction. The pair of long sides 111C and 111D extend along the X axis direction and face each other outward in the Z′ axis direction. The short side 111A is located at the end of the vibration section 110 on the negative side of the X axis. The short side 111B is located at the end of the vibration section 110 on the positive side of the X axis. The long side 111C is located at the end of the vibration section 110 on the positive side of the Z′ axis. The long side 111D is located at the end of the vibration section 110 on the negative side of the Z′ axis.

[0020] The main vibration of the vibrating part is not limited to the thickness shear vibration mode, and may be, for example, a thickness longitudinal vibration mode, an extensional vibration mode, a lengthwise vibration mode, or a bending vibration mode. Furthermore, the planar shape of the vibrating part is not limited to a rectangular shape, and may be, for example, a square shape, a polygonal shape, a circle shape, an ellipse shape, or a combination thereof.

[0021] The holding portion 120 is a portion for holding the vibration portion 110. As shown in Figures 1 to 3, the holding portion 120, together with the lower cover 20, the upper cover 30, the lower joint portion 40, and the upper joint portion 50, forms a vibration space for the vibration portion 110. As shown in Figure 5, in plan view, the holding portion 120 is provided in a frame-shaped region surrounding the vibration portion 110 with a gap therebetween.

[0022] 5, the holding unit 120 has frame portions 121A, 121B, 121C, and 121D. The frame portions 121A, 121B, 121C, and 121D are each part of a substantially rectangular frame surrounding the vibrating unit 110. The frame portion 121A is provided on the negative X-axis side of the vibrating unit 110, the frame portion 121B is provided on the positive X-axis side of the vibrating unit 110, the frame portion 121C is provided on the positive Z'-axis side of the vibrating unit 110, and the frame portion 121D is provided on the negative Z'-axis side of the vibrating unit 110. The frame portion 121A is provided at a distance from the short side 111A of the vibrating unit 110 in the X-axis direction and extends parallel to the short side 111A along the Z'-axis direction. Frame portion 121B is spaced apart from short side 111B of vibrating portion 110 in the X-axis direction and extends parallel to short side 111B along the Z'-axis direction. Frame portion 121C is spaced apart from long side 111C of vibrating portion 110 in the Z'-axis direction and extends parallel to long side 111C along the X-axis direction. Frame portion 121D is spaced apart from long side 111D of vibrating portion 110 in the Z'-axis direction and extends parallel to long side 111D along the X-axis direction.

[0023] Both ends of frame portion 121C are connected to one end of frame portion 121A and one end of frame portion 121B, respectively. Both ends of frame portion 121D are connected to the other end of frame portion 121A and the other end of frame portion 121B, respectively. Frame portion 121A and frame portion 121B face each other in the X-axis direction, with vibrating portion 110 sandwiched between them. Frame portion 121C and frame portion 121D face each other in the Z'-axis direction, with vibrating portion 110 sandwiched between them.

[0024] The holding portion is not limited to a frame-like shape as long as it is provided in at least a part of the frame-like region surrounding the vibrating portion. For example, the holding portion may be provided in the shape of a rail having two parallel frame portions.

[0025] The support arm 130 supports the vibration unit 110 and causes the holding unit 120 to hold the vibration unit 110. The support arm 130 connects the vibration unit 110 and the holding unit 120. As shown in FIG. 5 , the support arm 130 connects the end of the vibration unit 110 on the short side 111B side to the frame portion 121B of the holding unit 120. The support arm 130 extends along the X-axis. The dimension of the support arm 130 along the Z'-axis direction (hereinafter referred to as "width") is smaller than the width of the vibration unit 110.

[0026] The bottom cover 20 faces the vibrating portion 110, the holding portion 120, and the support arm 130 of the quartz-crystal vibrating element 10 at a distance in the Y'-axis direction. The bottom cover 20 is formed in a flat plate shape. As shown in FIG. 6 , in a plan view, the bottom cover 20 has a pair of long sides extending along the X-axis direction and facing each other in the Z'-axis direction, and a pair of short sides extending along the Z'-axis direction and facing each other in the X-axis direction. Furthermore, at the corners of the bottom cover 20 in a plan view, the long and short sides of the bottom cover 20 are connected by sides extending in a direction intersecting both the long and short sides. In other words, notches are formed at the four corners of the bottom cover 20 in a plan view.

[0027] The top cover 30 faces the vibrating portion 110, the holding portion 120, and the support arm 130 of the quartz vibrating element 10 at a distance in the Y'-axis direction on the opposite side from the bottom cover 20. The top cover 30 is formed in a flat plate shape. As shown in FIG. 1 , when viewed in a plan view, the top cover 30 has a pair of long sides extending along the X-axis direction and facing each other in the Z'-axis direction, and a pair of short sides extending along the Z'-axis direction and facing each other in the X-axis direction. The top cover 30 has a rectangular planar shape.

[0028] The lower bonding portion 40 and the upper bonding portion 50 are provided in a frame shape along the holding portion 120 of the quartz-crystal vibrating element 10. The lower bonding portion 40 bonds the holding portion 120 of the quartz-crystal vibrating element 10 to an end of the lower lid 20. The upper bonding portion 50 bonds the holding portion 120 of the quartz-crystal vibrating element 10 to an end of the upper lid 30. The lower bonding portion 40 and the upper bonding portion 50 are provided using an organic adhesive containing, for example, an epoxy-based, vinyl-based, acrylic-based, urethane-based, or silicone-based resin.

[0029] The material of the lower and upper joints is not limited to organic adhesives, and may be inorganic adhesives such as silicon-based adhesives containing water glass or calcium-based adhesives containing cement. The material of the lower and upper joints may be low-melting-point glass (e.g., lead borate-based or tin phosphate-based). The material of the lower and upper joints may be gold (Au), tin (Sn), copper (Cu), titanium (Ti), aluminum (Al), germanium (Ge), silicon (Si), or a eutectic alloy containing at least one of these. From the viewpoints of reducing raw material costs, streamlining the manufacturing process, and saving energy, it is preferable that the material of the lower and upper joints be an adhesive rather than a metal material such as a eutectic alloy.

[0030] The lower reinforcement portion 60 and the upper reinforcement portion 70 cover at least a portion of the support arm 130 and reinforce the mechanical strength of the support arm 130. The lower reinforcement portion 60 limits downward displacement of the support arm 130, i.e., toward the lower cover 20. As shown in FIGS. 2 and 3 , the lower reinforcement portion 60 connects the support arm 130 and the lower cover 20. The lower reinforcement portion 60 is provided in a columnar shape extending from the support arm 130 toward the lower cover 20 along the Y′-axis direction. The upper reinforcement portion 70 limits upward displacement of the support arm 130, i.e., toward the upper cover 30. As shown in FIGS. 2 and 3 , the upper reinforcement portion 70 connects the support arm 130 and the upper cover 30. The upper reinforcement portion 70 is provided in a columnar shape extending from the support arm 130 toward the upper cover 30 along the Y′-axis direction.

[0031] The elastic modulus of the lower reinforcement portion 60 is equal to that of the upper reinforcement portion 70. The elastic moduli of the lower reinforcement portion 60 and the upper reinforcement portion 70 are smaller than the elastic modulus of the quartz substrate 11 (described later), and desirably smaller than the elastic moduli of the lower bonding portion 40 and the upper bonding portion 50. The material of the lower reinforcement portion 60 is, for example, the same as the material of the upper reinforcement portion 70. The material of the lower reinforcement portion 60 and the upper reinforcement portion 70 is, for example, the same as the material of the lower bonding portion 40 and the upper bonding portion 50. The lower reinforcement portion 60 and the upper reinforcement portion 70 are provided using an organic adhesive containing, for example, an epoxy-based, vinyl-based, acrylic-based, urethane-based, or silicone-based resin.

[0032] The materials of the lower reinforcing portion and the upper reinforcing portion are not limited to those described above. The materials of the lower reinforcing portion and the upper reinforcing portion may be different from the materials of the lower joining portion and the upper joining portion. Furthermore, the material of the lower reinforcing portion may be different from the material of the upper reinforcing portion.

[0033] Next, the detailed configurations of the crystal vibrating element 10, the lower cover 20, the upper cover 30, the lower reinforcing portion 60, and the upper reinforcing portion 70 will be described.

[0034] The quartz crystal vibrating element 10 includes a quartz crystal substrate 11, a first excitation electrode 14a, a second excitation electrode 14b, a first extraction electrode 15a, a second extraction electrode 15b, a first connection electrode 16a, and a second connection electrode 16b.

[0035] The quartz crystal substrate 11 is a type of piezoelectric substrate made of a piezoelectric material that vibrates in response to an applied voltage. The quartz crystal substrate 11 is provided continuously across the vibrating part 110, the holding part 120, and the support arm 130. In the XZ' plane direction, the quartz crystal substrate 11 extends over almost the entire area of ​​each of the vibrating part 110, the holding part 120, and the support arm 130. The quartz crystal substrate 11 is a thin flake of quartz crystal with the XZ' plane as its main surface.

[0036] The quartz crystal substrate 11 is, for example, an AT-cut quartz crystal substrate. That is, when viewed from the positive X-axis side, the counterclockwise rotation angle θ of the Z'-axis and Y'-axis from the Z-axis and Y-axis is 35° 15 min ± 1 min 30 sec. The quartz crystal vibrating element 10 using the AT-cut quartz crystal substrate 11 has high frequency stability over a wide temperature range.

[0037] The cut angle of the quartz crystal substrate is not limited to the above. The rotation angles of the Y'-axis and Z'-axis in the AT-cut quartz crystal substrate 11 may be inclined within a range of -5 degrees or more or +15 degrees or less from 35 degrees 15 minutes. Furthermore, the cut angle of the quartz crystal substrate may be a different cut other than the AT cut, such as a BT cut, a GT cut, or an SC cut.

[0038] The planar shape of the quartz substrate 11 in the vibrating part 110 is a rectangle with long sides along the X-axis direction and short sides along the Z'-axis direction. As shown in FIG. 2 , in the vibrating part 110, the quartz substrate 11 has an upper surface 11A provided on the upper lid 30 side and a lower surface 11B provided on the lower lid 20 side. The upper surface 11A and the lower surface 11B face each other in the Y'-axis direction of the quartz substrate 11. The upper surface 11A corresponds to an example of a first main surface of the quartz substrate 11 in the vibrating part 110. The lower surface 11B corresponds to an example of a second main surface of the quartz substrate 11 in the vibrating part 110.

[0039] As shown in Fig. 4, in a plan view, the vibrating part 110 has a central part 117 and a peripheral part 118. The central part 117 is provided in the center of the vibrating part 110, and the peripheral part 118 is provided around the central part 117. In a plan view, the peripheral part 118 surrounds the central part 117. The thickness of the quartz substrate 11 in the central part 117 is approximately equal to the thickness of the quartz substrate 11 in the peripheral part 118. That is, in the vibrating part 110, the quartz substrate 11 is a flat plate with a uniform thickness.

[0040] The planar shape of the vibrating portion of the quartz substrate is not limited to the above. For example, the planar shape of the vibrating portion of the quartz substrate may be rectangular with long sides extending in the Z'-axis direction and short sides extending in the X-axis direction, or may be rectangular with short sides extending in the Z'-axis direction and long sides extending in the X-axis direction. The planar shape of the vibrating portion of the quartz substrate may be polygonal, circular, elliptical, or a combination thereof. Furthermore, the vibrating portion of the quartz substrate is not limited to a flat plate shape, and may have a different thickness in the central portion from that in the peripheral portion. For example, the vibrating portion of the quartz substrate may have a mesa structure in which at least one of the upper and lower surfaces is convex in the center, or an inverted mesa structure in which at least one of the upper and lower surfaces is concave in the center. The vibrating portion of the quartz substrate may have a convex structure in which the thickness changes continuously from the peripheral portion to the central portion, or a bevel structure in which the thickness changes discontinuously.

[0041] As shown in Fig. 5, the planar shape of the quartz substrate 11 in the holding unit 120 is a rectangular frame shape with long sides along the X-axis direction and short sides along the Z'-axis direction. As shown in Fig. 2, in the holding unit 120, the quartz substrate 11 has an upper surface 12A provided on the upper lid 30 side and a lower surface 12B provided on the lower lid 20 side. The upper surface 12A corresponds to an example of a first main surface of the quartz substrate 11 in the holding unit 120. The lower surface 12B corresponds to an example of a second main surface of the quartz substrate 11 in the holding unit 120.

[0042] 2, the thickness of the quartz substrate 11 in the holding portion 120 is greater than the thickness of the quartz substrate 11 in the vibrating portion 110. The thicknesses of the quartz substrate 11 in each of the frame portions 121A, 121B, 121C, and 121D are approximately equal to one another. However, the thickness of the quartz substrate 11 in the holding portion may be equal to the thickness of the quartz substrate 11 in the vibrating portion, or may be smaller than the thickness of the quartz substrate 11 in the vibrating portion.

[0043] As shown in FIG. 5 , the planar shape of the quartz substrate 11 in the support arm 130 is a rectangular frame. As shown in FIG. 3 , in the support arm 130, the quartz substrate 11 has an upper surface 13A, a lower surface 13B, and side surfaces 13C and 13D. The upper surface 13A faces the upper cover 30, and the lower surface 13B faces the lower cover 20. The side surface 13C connects the ends of the upper surface 13A and the lower surface 13B on the positive side of the Z′ axis and faces the frame portion 121C. The side surface 13D connects the ends of the upper surface 13A and the lower surface 13B on the negative side of the Z′ axis and faces the frame portion 121D. The upper surface 13A corresponds to an example of a first main surface of the quartz substrate 11 in the support arm 130. The lower surface 13B corresponds to an example of a second main surface of the quartz substrate 11 in the support arm 130. The side surface 13C corresponds to an example of a first side surface of the quartz substrate 11 in the support arm 130. The side surface 13D corresponds to an example of a second side surface of the quartz substrate 11 on the support arm 130 .

[0044] The side surfaces 13C and 13D are each formed of, for example, a single flat surface extending along the XY' plane, but are not limited to this. The side surfaces of the support arms may be formed of multiple surfaces including inclined surfaces extending in a direction intersecting the XY' plane, or may include curved surfaces.

[0045] As shown in FIG. 2, the support arm 130 has a connection portion 131 connected to the vibration portion 110 and a connection portion 132 connected to the holding portion 120 .

[0046] The quartz substrate 11 in the support arm 130 is formed in a flat plate shape with a uniform thickness. As shown in Fig. 2, the thickness of the quartz substrate 11 in the support arm 130 is approximately equal to the thickness of the quartz substrate 11 in the vibrating portion 110 and is smaller than the thickness of the quartz substrate 11 in the holding portion 120. In other words, the upper surface 11A and the upper surface 13A are provided continuously in the XZ' plane direction, and the lower surface 11B and the lower surface 13B are provided continuously in the XZ' plane direction. In addition, a step is provided between the upper surface 13A and the upper surface 12A, and a step is provided between the lower surface 13B and the lower surface 12B.

[0047] The thickness of the quartz substrate in the support arm is not limited to the above. The thickness of the quartz substrate in the support arm may vary. For example, convex or concave portions may be provided on the upper and lower surfaces of the quartz substrate in the support arm. When the quartz substrate in the support arm has such convex or concave portions, the convex or concave portions can limit the wetting and spreading of the adhesive forming the lower reinforcement portion and the upper reinforcement portion. In other words, the shape and dimensions of the lower reinforcement portion and the upper reinforcement portion can be controlled by the shape of the convex or concave portion of the quartz substrate in the support arm.

[0048] The thickness of the quartz substrate in the support arms may be smaller than that of the quartz substrate in the vibrating section and may be equal to that of the quartz substrate in the holding section, or may be larger than that of the quartz substrate in the vibrating section and smaller than that of the quartz substrate in the holding section.

[0049] The first excitation electrode 14a and the second excitation electrode 14b apply an AC voltage to the quartz substrate 11 of the vibrating part 110 to excite the vibrating part 110. The first excitation electrode 14a and the second excitation electrode 14b are provided in the center 117 of the vibrating part 110. As shown in FIG. 2, the first excitation electrode 14a is provided on the upper surface 11A of the quartz substrate 11 of the vibrating part 110, and the second excitation electrode 14b is provided on the lower surface 11B of the quartz substrate 11 of the vibrating part 110. The first excitation electrode 14a and the second excitation electrode 14b face each other in the Y'-axis direction with the quartz substrate 11 therebetween. As shown in FIG. 5, in a plan view, the first excitation electrode 14a and the second excitation electrode 14b are rectangular and are arranged so that they substantially entirely overlap each other.

[0050] The planar shapes of the first excitation electrode and the second excitation electrode are not limited to rectangular. The planar shapes of the first excitation electrode and the second excitation electrode may be polygonal, circular, elliptical, or a combination thereof. The planar shape of the first excitation electrode is not limited to being the same as the planar shape of the second excitation electrode, and the planar shapes of the first excitation electrode and the second excitation electrode may be different from each other. When viewed in a planar view, the area of ​​the first excitation electrode is, for example, approximately equal to the area of ​​the second excitation electrode, but may be different from the area of ​​the second excitation electrode.

[0051] 1, the first extraction electrode 15a extracted from the first excitation electrode 14a extends over the upper surfaces of the vibration unit 110, the support arm 130, and the frame portion 121B of the holding unit 120, as well as the side surfaces of the holding unit 120, and is electrically connected to the first connection electrode 16a provided on the lower surface of the holding unit 120. The second extraction electrode 15b extracted from the second excitation electrode 14b extends over the lower, side, and upper surfaces of the vibration unit 110 and the support arm 130, the upper surfaces of the frame portions 121B and 121D of the holding unit 120, and the side surfaces of the holding unit 120, and is electrically connected to the second connection electrode 16b provided on the lower surface of the holding unit 120.

[0052] The first connection electrode 16a electrically connects the first excitation electrode 14a to an external terminal, and the second connection electrode 16b electrically connects the second excitation electrode 14b to an external terminal. As shown in Fig. 1, the first connection electrode 16a is provided on the lower surface 12B of the quartz crystal substrate 11 at a corner of the holding portion 120 where the frame portion 121B and the frame portion 121C are connected. The second connection electrode 16b is provided on the lower surface 12B of the quartz crystal substrate 11 at a corner of the holding portion 120 where the frame portion 121A and the frame portion 121D are connected.

[0053] The first excitation electrode 14a, the first extraction electrode 15a, and the first connection electrode 16a are integrally formed. The same is true for the second excitation electrode 14b, the second extraction electrode 15b, and the second connection electrode 16b. The electrodes of the quartz crystal vibrating element 10 have, for example, a single-layer structure made of an aluminum layer, but this is not limited thereto. The electrodes of the quartz crystal vibrating element may also have a multilayer structure in which a base layer and a surface layer are stacked in this order. For example, the base layer is a chromium (Cr) layer that has good adhesion to the quartz crystal substrate, and the surface layer is a gold (Au) layer that has good chemical stability. The electrodes of the quartz crystal vibrating element may contain silver (Ag), copper (Cu), titanium (Ti), molybdenum (Mo), or an aluminum-copper alloy (AlCu).

[0054] The bottom cover 20 includes a quartz crystal substrate 21, power supply terminals ST1 and ST2, and dummy terminals DT1 and DT2. The quartz crystal substrate 21 is a flat substrate that overlaps substantially the entire quartz crystal vibrating element 10 in a planar view. The quartz crystal substrate 21 is formed from quartz crystal with the same cut angle as the quartz crystal substrate 11 of the quartz crystal vibrating element 10. This reduces thermal stress caused by differences in thermal expansion coefficients and directions of thermal expansion and contraction between the quartz crystal vibrating element 10 and the bottom cover 20. This suppresses fluctuations in the frequency of the quartz crystal vibrating element 10. The quartz crystal substrate 21 has an upper surface 21A provided on the quartz crystal vibrating element 10 side and a lower surface 21B provided on the opposite side from the upper surface 21A. In a planar view, the quartz crystal substrate 21 has long sides extending along the X-axis direction and short sides extending along the Z'-axis direction. A notch is formed at the corner where the short side and long side of the quartz crystal substrate 21 connect. The area of ​​the quartz substrate 21 in a plan view is smaller than the area of ​​the quartz substrate 31 in a plan view, which will be described later, by the amount of the cutout. The shape of the side surface formed by the cutout at the corner of the quartz substrate 21 is, for example, flat. However, the shape of the side surface formed by the cutout at the corner of the quartz substrate 21 is not limited to this, and may be a curved surface that is part of the side surface of a cylinder or a rectangular prism.

[0055] The power supply terminals ST1 and ST2 and the dummy terminals DT1 and DT2 are provided on the lower surface 21B of the quartz crystal substrate 21. The power supply terminals ST1 and ST2 and the dummy terminals DT1 and DT2 correspond to examples of external terminals of the quartz crystal unit 1. The power supply terminals ST1 and ST2 are used to apply a drive signal (drive voltage) to the quartz crystal unit 1. The power supply terminal ST1 is electrically connected to the first connection electrode 16a via a notch in a corner of the quartz crystal substrate 21 and a side electrode 162a provided on the outer surface of the lower joint 40. The power supply terminal ST2 is electrically connected to the second connection electrode 16b via a notch in a corner of the quartz crystal substrate 21 and a side electrode 162b provided on the outer surface of the lower joint 40. The dummy terminals DT1 and DT2 are used to balance electrical characteristics such as capacitance and mechanical strength between the power supply terminals ST1 and ST2. The dummy terminals DT1 and DT2 are so-called floating electrodes that are not electrically connected to the quartz crystal vibrating element 10.

[0056] At least one of the dummy terminals DT1 and DT2 may be a ground electrode that electrically grounds a part of the crystal resonator 1.

[0057] The top cover 30 has a quartz crystal substrate 31. The quartz crystal substrate 31 is a flat substrate that overlaps substantially the entire quartz crystal vibrating element 10 in a planar view. The quartz crystal substrate 31 is formed from quartz crystals with the same cut angle as the quartz crystal substrate 11 of the quartz crystal vibrating element 10. This reduces thermal stress caused by differences in thermal expansion coefficients and directions of thermal expansion and contraction between the quartz crystal vibrating element 10 and the top cover 30. This suppresses fluctuations in the frequency of the quartz crystal vibrating element 10. The quartz crystal substrate 31 has a bottom surface 31B provided on the quartz crystal vibrating element 10 side and a top surface 31A provided on the opposite side from the bottom surface 31B. In a planar view, the quartz crystal substrate 31 has a rectangular shape with long sides extending along the X-axis direction and short sides extending along the Z'-axis direction.

[0058] The cut angles of the quartz substrates 21, 31 of the lower cover 20 and the upper cover 30 are not particularly limited and may be different from the cut angle of the quartz substrate 11 of the quartz vibrating element 10. Furthermore, instead of the quartz substrates 21, 31, the lower cover 20 and the upper cover 30 may have a glass substrate, a silicon substrate, a ceramic substrate, a metal substrate, or a composite substrate that combines these.

[0059] As shown in FIGS. 3 and 4 , the lower reinforcement portion 60 is provided continuously from the end of the lower surface 13B on the side surface 13C side to the end on the side surface 13D side at the connection portion 132 between the support arm 130 and the holding portion 120. The lower reinforcement portion 60 is provided continuously from the lower surface 13B to the side surface 13C at the connection portion 132, covering the corner where the lower surface 13B and the side surface 13C connect. The lower reinforcement portion 60 is also provided continuously from the lower surface 13B to the side surface 13D at the connection portion 132, covering the corner where the lower surface 13B and the side surface 13D connect. The lower reinforcement portion 60 is connected to the lower joint portion 40. As shown in FIG. 4 , in a plan view, the lower reinforcement portion 60 extends from a portion provided along the frame portion 121B of the lower joint portion 40 along the support arm 130 toward the vibrating portion 110. The material of the lower reinforcing portion 60 is, for example, the same as the material of the lower joining portion 40. In such a case, the lower reinforcing portion 60 and the lower joining portion 40 can be formed simultaneously by the same process.

[0060] As shown in FIGS. 3 and 4 , the upper reinforcement portion 70 is provided continuously from the end of the upper surface 13A on the side surface 13C side to the end on the side surface 13D side at the connection portion 132 between the support arm 130 and the holding portion 120. The upper reinforcement portion 70 is provided continuously from the upper surface 13A to the side surface 13C at the connection portion 132, covering the corner where the upper surface 13A and the side surface 13C connect. The upper reinforcement portion 70 is also provided continuously from the upper surface 13A to the side surface 13D at the connection portion 132, covering the corner where the upper surface 13A and the side surface 13D connect. The upper reinforcement portion 70 is connected to the upper joint portion 50. As shown in FIG. 4 , in a plan view, the upper reinforcement portion 70 extends from a portion of the upper joint portion 50 along the frame portion 121B, along the support arm 130, toward the vibrating portion 110. The material of the upper reinforcing portion 70 is, for example, the same as the material of the upper joining portion 50. In such a case, the upper reinforcing portion 70 and the upper joining portion 50 can be formed simultaneously by the same process.

[0061] 3, the lower reinforcing portion 60 and the upper reinforcing portion 70 are connected to each other at a connection portion 132 where the support arm 130 is connected to the holding portion 120. At the connection portion 132, the support arm 130 is surrounded by the lower reinforcing portion 60 and the upper reinforcing portion 70.

[0062] The regions where the lower reinforcement portion 60 and the upper reinforcement portion 70 are provided are not limited to those described above. The lower reinforcement portion 60 may be provided only on the lower surface 13B of the support arm 130, among the lower surface 13B and the side surfaces 13C and 13D. The lower reinforcement portion 60 may be provided on one of the side surfaces 13C and 13D of the support arm 130 and spaced apart from the other side surface. The lower reinforcement portion 60 may be provided on the entire lower surface 13B of the support arm 130, or on the entire side surfaces 13C and 13D of the support arm 130. The lower reinforcement portion 60 may be spaced apart from the end of the lower surface 13B of the support arm 130 on the side surface 13C side, i.e., the corner where the lower surface 13B and the side surface 13C are connected. The lower reinforcement portion 60 may be spaced apart from the end of the lower surface 13B of the support arm 130 on the side surface 13D side, i.e., the corner where the lower surface 13B and the side surface 13D connect. The lower reinforcement portion 60 may be spaced apart from the connection portion 132 of the support arm 130 with the holding portion 120. The lower reinforcement portion 60 may extend to the connection portion 131 of the support arm 130 with the vibrating portion 110. From the viewpoint of suppressing deterioration of the vibration characteristics of the quartz-crystal vibrating element 10, it is desirable that the lower reinforcement portion 60 be spaced apart from the vibrating portion 110. However, the lower reinforcement portion 60 may extend from the support arm 130 to the peripheral portion 118 of the vibrating portion 110 as long as it is spaced apart from the central portion 117 of the vibrating portion 110. The same applies to the upper reinforcement portion 70.

[0063] The lower reinforcement portion 60 and the upper reinforcement portion 70 are, for example, arranged to be substantially symmetrical from top to bottom, but are not limited to this. The planar shape and planar dimensions of the lower reinforcement portion 60 may be different from the planar shape and planar dimensions of the upper reinforcement portion 70. The cross-sectional shape and cross-sectional dimensions of the lower reinforcement portion 60 along the XY' plane may be different from the cross-sectional shape and cross-sectional dimensions of the upper reinforcement portion 70 along the XY' plane. The cross-sectional shape and cross-sectional dimensions of the lower reinforcement portion 60 along the Y'Z' plane may be different from the cross-sectional shape and cross-sectional dimensions of the upper reinforcement portion 70 along the Y'Z' plane. For example, one of the lower reinforcement portion 60 and the upper reinforcement portion 70 may extend to the connection portion 132 with the holding portion 120 of the support arm 130, and the other reinforcement portion may be spaced apart from the connection portion 132. Furthermore, one of the lower reinforcing portion 60 and the upper reinforcing portion 70 may extend to the connection portion 131 of the support arm 130 with the vibrating portion 110 , and the other reinforcing portion may be spaced apart from the connection portion 131 .

[0064] The lower reinforcing portion 60 and the upper reinforcing portion 70 are connected to each other, for example, but are not limited to this. The lower reinforcing portion 60 and the upper reinforcing portion 70 may be spaced apart from each other.

[0065] It should be noted that one of the lower reinforcement portion 60 and the upper reinforcement portion 70 may be omitted. When the lower reinforcement portion 60 is omitted, the upper reinforcement portion 70 may extend to the lower surface 13B of the support arm 130. When the upper reinforcement portion 70 is omitted, the lower reinforcement portion 60 may extend to the upper surface 13A of the support arm 130.

[0066] The lower reinforcement portion 60 is connected to a portion of the lower joint 40 that is provided along the frame portion 121B, but is not limited to this. Similarly, the upper reinforcement portion 70 is connected to a portion of the upper joint 50 that is provided along the frame portion 121B, but is not limited to this. For example, the lower reinforcement portion 60 may be spaced apart from the lower joint 40, and the upper reinforcement portion 70 may be spaced apart from the upper joint 50. The lower reinforcement portion 60 may be connected to at least one of the portions of the lower joint 40 that are provided along the frame portion 121C and the frame portion 121D. The upper reinforcement portion 70 may be connected to at least one of the portions of the upper joint 50 that are provided along the frame portion 121C and the frame portion 121D.

[0067] As described above, in one aspect of this embodiment, the quartz crystal resonator 1 includes the reinforcing portions 60 and 70 that cover at least a portion of the support arm 130 .

[0068] As a result, the reinforcing portions 60 and 70 reinforce the mechanical strength of the support arms 130. Furthermore, the reinforcing portions 60 and 70 limit excessive displacement of the support arms 130. When the vibrating portion 110 is excessively displaced due to an impact such as a fall, by reinforcing the support arms 130, on which external stress is likely to concentrate, damage to the quartz crystal vibrating element 10 can be suppressed. Therefore, the reliability of the quartz crystal vibrator 1 can be improved.

[0069] In one aspect of the above, the reinforcing portions 60 and 70 include a lower reinforcing portion 60 that connects the support arm 130 and the lower cover 20 , and an upper reinforcing portion 70 that connects the support arm 130 and the upper cover 30 .

[0070] This makes it possible to more effectively reinforce the mechanical strength of the support arm 130 compared to a configuration in which only one of the lower reinforcing portion 60 and the upper reinforcing portion 70 is provided. Furthermore, since the lower reinforcing portion 60 limits the displacement of the support arm 130 in the direction toward the lower cover 20, and the upper reinforcing portion 70 limits the displacement of the support arm 130 in the direction toward the upper cover 30, excessive displacement of the support arm 130 in both the direction toward the lower cover 20 and the direction toward the upper cover 30 can be limited. Therefore, damage to the quartz crystal vibrating element 10 can be more effectively suppressed.

[0071] In one aspect of the above, the lower reinforcement portion 60 is provided from the end portion on the side 13C side of the lower surface 13B of the support arm 130 to the end portion on the side 13D side, and the upper reinforcement portion 70 is provided from the end portion on the side 13C side of the upper surface 13A of the support arm 130 to the end portion on the side 13D side.

[0072] This reinforces the support arm 130 across its entire width, further limiting excessive displacement of the support arm 130 in the direction toward the lower cover 20 or the upper cover 30. It also limits displacement of the support arm 130 in the torsional direction around the X-axis as the axis of rotation. This makes it possible to more effectively prevent damage to the quartz crystal vibrating element 10.

[0073] In one aspect of the above, the lower reinforcing portion 60 and the upper reinforcing portion 70 cover the corners of the connection portion 132 of the support arm 130 with the holding portion 120 .

[0074] According to this, the corners of the connection portion 132, where external stress is particularly concentrated, are reinforced by the reinforcing portions 60, 70. Therefore, damage to the crystal vibrating element 10 can be more effectively suppressed.

[0075] In one embodiment of the above, the material of the lower reinforcing portion 60 is the same as the material of the lower joining portion 40 , and the material of the upper reinforcing portion 70 is the same as the material of the upper joining portion 50 .

[0076] According to this, the lower reinforcing portion 60 can be formed simultaneously in the process of forming the lower joint portion 40, and the upper reinforcing portion 70 can be formed simultaneously in the process of forming the upper joint portion 50. Therefore, the manufacturing process can be simplified compared to a configuration in which the lower reinforcing portion 60 and the lower joint portion 40 are made of different materials, and the upper reinforcing portion 70 and the upper joint portion 50 are made of different materials.

[0077] Other embodiments will be described below. Note that components that are the same as or similar to those in the first embodiment are denoted by the same or similar reference numerals, and descriptions thereof will be omitted as appropriate. Furthermore, similar effects resulting from similar components will not be mentioned one after another.

[0078] Second Embodiment Next, the configuration of a quartz crystal resonator 2 according to a second embodiment will be described with reference to Fig. 7. Fig. 7 is a cross-sectional view of the quartz crystal resonator according to the second embodiment.

[0079] In the quartz crystal resonator 2 , the lower reinforcing portion 260 and the upper reinforcing portion 270 extend to the connection portion 131 of the support arm 130 with the vibrating portion 110 .

[0080] This provides stronger reinforcement to the support arms 130, making it possible to more effectively prevent damage to the quartz crystal vibrating element 10.

[0081] Third Embodiment Next, the configuration of a quartz crystal resonator 3 according to a third embodiment will be described with reference to Fig. 8 and Fig. 9. Fig. 8 is a cross-sectional view of the quartz crystal resonator according to the third embodiment. Fig. 9 is a plan view of the quartz crystal resonator according to the third embodiment.

[0082] In the quartz crystal unit 3, the lower reinforcement portion 360 is spaced apart from the lower joint portion 40, and the upper reinforcement portion 370 is spaced apart from the upper joint portion 50. The lower reinforcement portion 360 is provided in an island shape in the region surrounded by the lower joint portion 40, separated from any of the portions provided along each of the frame portions 121A to 121D of the lower joint portion 40. The upper reinforcement portion 370 is provided in an island shape in the region surrounded by the upper joint portion 50, separated from any of the portions provided along each of the frame portions 121A to 121D of the upper joint portion 50.

[0083] Fourth Embodiment Next, the configuration of a quartz crystal resonator 4 according to a fourth embodiment will be described with reference to Fig. 10. Fig. 10 is a cross-sectional view of the quartz crystal resonator according to the fourth embodiment.

[0084] In the quartz crystal unit 4, the upper surface 421A of the quartz crystal substrate 421 of the lower cover 420 is recessed. The quartz crystal substrate 421 has a flat bottom wall 422 and a side wall 423 extending from the outer edge of the bottom wall 422 toward the holder 120. The bottom wall 422 and the side wall 423 form a cavity 429. The lower surface 431B of the quartz crystal substrate 431 of the upper cover 430 is recessed. The quartz crystal substrate 431 has a flat bottom wall 432 and a side wall 433 extending from the outer edge of the bottom wall 432 toward the holder 120. The bottom wall 432 and the side wall 433 form a cavity 439. In a plan view, bottom wall portions 422, 432 overlap the entire vibrating portion 110, and side wall portions 423, 433 surround vibrating portion 110 with a gap therebetween. That is, lower lid 420 is provided with a cavity 429 that is larger than vibrating portion 110 in a plan view, and upper lid 430 is provided with a cavity 439 that is larger than vibrating portion 110 in a plan view. Cavity 439 corresponds to an example of a first cavity, and cavity 429 corresponds to an example of a second cavity.

[0085] This expands the vibration space of the vibration part 110. Therefore, even if the crystal unit 4 is miniaturized, the vibration space of the vibration part 110 can be secured.

[0086] Fifth Embodiment Next, the configuration of a quartz crystal resonator 3 according to a fifth embodiment will be described with reference to Fig. 11 and Fig. 12. Fig. 11 is a cross-sectional view of the quartz crystal resonator according to the fifth embodiment. Fig. 12 is a plan view of the quartz crystal resonator according to the fifth embodiment.

[0087] In the quartz crystal resonator 5, an opening 519 is provided in the peripheral portion 518B, which opens to both the upper surface 11A and the lower surface 11B of the quartz crystal substrate 511. The peripheral portion 518B is a portion of the peripheral portion 518 of the vibrating portion 510 that is located between the central portion 117 and the support arm 130. The opening 519 is provided in the shape of a slot having a longitudinal direction extending in the Z'-axis direction. The opening 519 penetrates the quartz crystal substrate 511 in the thickness direction. The width of the opening 519 is greater than the width of the support arm 130.

[0088] In a plan view, the opening 519 has inner surfaces 519C and 519D. The inner surface 519C constitutes the end of the opening 519 on the frame portion 121C side. The inner surface 519D constitutes the end of the opening 519 on the frame portion 121D side. The side surfaces 13C and 13D of the support arm 130 are located closer to the inner surface 519D of the opening 519 than the inner surface 519C of the opening 519. Furthermore, the side surfaces 13C and 13D of the support arm 130 are located closer to the inner surface 519C of the opening 519 than the inner surface 519D of the opening 519. In a plan view, the center of the opening 519 and the center of the support arm 130 are aligned in the X-axis direction. The opening 519 suppresses vibration leakage from the vibrating unit 510. Furthermore, the propagation of external stress to the central portion 117 is suppressed.

[0089] 11 and 12 , the lower reinforcing portion 60 and the upper reinforcing portion 70 are spaced apart from the connection portion 131 between the support arm 130 and the vibrating portion 510. However, in this embodiment, external stress tends to concentrate at the corners of the connection portion 131, so it is desirable that the lower reinforcing portion 60 and the upper reinforcing portion 70 extend to the connection portion 131, and it is even more desirable that they cover the corners of the connection portion 131.

[0090] Sixth Embodiment Next, the configuration of a quartz crystal resonator 6 according to a sixth embodiment will be described with reference to Fig. 13 and Fig. 14. Fig. 13 is a cross-sectional view of the quartz crystal resonator according to the sixth embodiment. Fig. 14 is a plan view of the quartz crystal resonator according to the sixth embodiment.

[0091] In the quartz crystal resonator 6, a groove 625 is provided on the upper surface 621A of the quartz crystal substrate 621 of the lower cover 620, along with the holding portion 120. The groove 625 is provided in a concave shape that opens toward the upper cover 630. A groove 635 is provided on the upper surface 631B of the quartz crystal substrate 631 of the upper cover 630, along with the holding portion 120. The groove 635 is provided in a concave shape that opens toward the lower cover 620. In a plan view, the grooves 625 and 635 are provided in a frame-shaped region that surrounds the vibrating portion 110. The grooves 625 and 635 are provided continuously along the frame portions 121A, 121C, and 121D. The grooves 625 and 635 are provided discontinuously along the frame portion 121B to avoid the region that overlaps with the portion where the support arm 130 and the holding portion 120 are connected. When viewed from above, the groove 625 and the groove 635 overlap each other.

[0092] When the lower bonding portion 40 is provided using a paste-like adhesive, the groove 625 limits the spread of the adhesive on the lower cover 620, thereby suppressing an increase in the surface area of ​​the lower bonding portion 40. Similarly, the groove 635 limits the spread of the adhesive on the upper cover 630, thereby suppressing an increase in the surface area of ​​the upper bonding portion 50. This suppresses the generation of outgassing from the lower bonding portion 40 and the upper bonding portion 50. Therefore, fluctuations in frequency characteristics caused by adhesion of outgassing to the vibrating portion 110 are suppressed, improving the reliability of the quartz crystal unit 6.

[0093] Groove portions 625 and 635 may be provided discontinuously in the region along frame portions 121A, 121C, and 121D. Groove portions 625 and 635 may also be provided discontinuously outside the region that overlaps with the portion where support arm 130 and holding portion 120 are connected, within the region along frame portion 121B.

[0094] Note that, as long as the lower cover 620 and the upper cover 630 are provided with a structure that limits the spreading of the adhesive, convex banks may be provided instead of the grooves 625, 635. Furthermore, the lower cover 620 and the upper cover 630 may be provided with both the concave grooves 625, 635 and the convex banks.

[0095] Some or all of the embodiments of the present invention will be described below, but the present invention is not limited to the following descriptions.

[0096] <1> A piezoelectric vibrator comprising: a piezoelectric vibrating element having a vibrating portion, a holding portion provided in at least a part of a frame-shaped region surrounding the vibrating portion at a distance from the vibrating portion, and a support arm connecting the vibrating portion and the holding portion to support the vibrating portion; a first substrate provided opposite the piezoelectric vibrating element; a second substrate provided opposite the piezoelectric vibrating element on the side opposite the first substrate; a first bonding portion bonding the holding portion of the piezoelectric vibrating element to the first substrate; a second bonding portion bonding the holding portion of the piezoelectric vibrating element to the second substrate; and a reinforcing portion made of resin that covers at least a part of the support arm.

[0097] <2> The piezoelectric vibration element according to <1>, wherein the reinforcing portion has: a first reinforcing portion that connects the support arm and the first substrate; and a second reinforcing portion that connects the support arm and the second substrate.

[0098] <3> The piezoelectric vibration element described in <2>, wherein the support arm has a first main surface facing the first substrate, a second main surface facing the second substrate, a first side surface connecting the first main surface and the second main surface, and a second side surface opposite the first side surface connecting the first main surface and the second main surface, the first reinforcing portion being provided from the end of the first main surface on the first side surface side to the end of the second side surface side, and the second reinforcing portion being provided from the end of the second main surface on the first side surface side to the end of the second main surface on the second side surface side.

[0099] <4> The piezoelectric vibration element according to any one of <1> to <3>, wherein the reinforcing portion covers a corner of a connection portion of the support arm with the holding portion.

[0100] <5> The piezoelectric vibration element according to any one of <1> to <4>, wherein the reinforcing portion is connected to the first bonding portion or the second bonding portion.

[0101] <6> The piezoelectric vibration element according to any one of <1> to <5>, wherein the reinforcing portion extends to a connection portion of the supporting arm with the vibration portion.

[0102] <7> The piezoelectric vibration element according to any one of <1> to <6>, wherein the reinforcing portion is spaced apart from the first bonding portion and the second bonding portion.

[0103] <8> The piezoelectric vibration element described in any one of <1> to <7>, wherein a first cavity larger than the vibration portion in a planar view is provided on the piezoelectric vibration element side of the first substrate, and a second cavity larger than the vibration portion in a planar view is provided on the piezoelectric vibration element side of the second substrate.

[0104] <9> The piezoelectric vibration element according to any one of <1> to <8>, wherein the vibration part has a central part where an excitation electrode is provided and a peripheral part surrounding the central part, and an opening part that opens to both the first substrate side and the second substrate side is provided between the central part of the vibration part and the support arm.

[0105] <10> A piezoelectric vibration element described in <9>, wherein, when the longitudinal direction of the opening in a planar view is the width direction, the support arm has a first side surface provided on one side in the width direction and a second side surface provided on the opposite side of the first side surface in the width direction, the opening has a first inner side surface provided on one side in the width direction and a second inner side surface provided on the opposite side of the first inner side surface in the width direction, the first side surface is located on the second inner side surface side relative to the first inner side surface, and the second side surface is located on the first inner side surface side relative to the second inner side surface.

[0106] <11> The piezoelectric vibration element described in any one of <1> to <10>, wherein a groove portion is provided in a part of a frame-shaped region surrounding the vibration portion in a planar view on the piezoelectric vibration element side of the first substrate and the second substrate, and the groove portion is provided so as to avoid an area overlapping with a portion where the support arm and the holding portion are connected in a planar view.

[0107] <12> The piezoelectric vibration element according to any one of <1> to <11>, wherein the material of the reinforcing portion is the same as the material of the first bonding portion and the second bonding portion.

[0108] In this specification, a quartz crystal resonator having a quartz crystal substrate as a piezoelectric substrate has been described as an example, but the piezoelectric resonator is not limited to this. Examples of piezoelectric substrates suitable for use in the piezoelectric vibrator according to this embodiment include piezoelectric ceramics such as lead zirconate titanate (PZT) and aluminum nitride, and piezoelectric single crystals such as lithium niobate and lithium tantalate, but the substrate is not limited to these and can be selected as appropriate.

[0109] The embodiments according to the present invention are not particularly limited and can be appropriately applied to any device that performs electromechanical energy conversion using the piezoelectric effect, such as a timing device, a sound generator, an oscillator, or a load sensor.

[0110] As described above, according to one aspect of the present invention, it is possible to provide a piezoelectric vibrator that can improve reliability.

[0111] The above-described embodiments are intended to facilitate understanding of the present invention and are not intended to limit the scope of the present invention. The present invention may be modified or improved without departing from its spirit, and equivalents are also included within the scope of the present invention. In other words, designs modified by those skilled in the art as appropriate to the embodiments and / or modifications are also encompassed within the scope of the present invention as long as they incorporate the characteristics of the present invention. For example, the elements and their arrangements, materials, conditions, shapes, sizes, etc. of the embodiments and / or modifications are not limited to those illustrated and can be modified as appropriate. Furthermore, the embodiments and modifications are merely examples, and it goes without saying that partial substitutions or combinations of the components shown in different embodiments and / or modifications are possible. These are also encompassed within the scope of the present invention as long as they incorporate the characteristics of the present invention.

[0112] 1... Crystal vibrator 10... Crystal vibrating element 11... Crystal substrate 110... Vibrating portion 120... Holding portion 130... Support arm 20... Lower cover 30... Upper cover 40... Lower joint 50... Upper joint 60... Lower reinforcement 70... Upper reinforcement 11A, 12A, 13A, 21A, 31A... Upper surface 11B, 12B, 13B, 21B, 31B... Lower surface 14a... First excitation electrode 14b... Second excitation electrode 15a... First lead electrode 15b... Second lead electrode 16a... First connecting electrode 16b... Second connecting electrode

Claims

1. A piezoelectric vibrator comprising: a vibrating portion; a holding portion provided at least in part in a frame-shaped region surrounding the vibrating portion with a space therebetween; a support arm connecting the vibrating portion and the holding portion to support the vibrating portion; a first substrate provided opposite to the piezoelectric vibrator; a second substrate provided opposite to the piezoelectric vibrator on the side opposite to the first substrate; a first bonding portion bonding the holding portion of the piezoelectric vibrator and the first substrate; a second bonding portion bonding the holding portion of the piezoelectric vibrator and the second substrate; and a reinforcing portion made of resin covering at least a part of the support arm.

2. The piezoelectric vibrator according to claim 1, wherein the reinforcing portion includes a first reinforcing portion connecting the support arm and the first substrate, and a second reinforcing portion connecting the support arm and the second substrate.

3. The support arm has a first main surface facing the first substrate, a second main surface facing the second substrate, a first side surface connecting the first main surface and the second main surface, and a second side surface connecting the first main surface and the second main surface on the side opposite to the first side surface. The first reinforcing portion is provided from an end portion on the first side surface side of the first main surface to an end portion on the second side surface side, and the second reinforcing portion is provided from an end portion on the first side surface side of the second main surface to an end portion on the second side surface side. The piezoelectric vibrator according to claim 2.

4. The piezoelectric vibrator according to any one of claims 1 to 3, wherein the reinforcing portion covers a corner portion of a connection portion between the support arm and the holding portion.

5. The piezoelectric vibrator according to any one of claims 1 to 4, wherein the reinforcing portion is connected to the first bonding portion or the second bonding portion.

6. The piezoelectric vibrator according to any one of claims 1 to 5, wherein the reinforcing portion extends to a connection portion between the support arm and the vibrating portion.

7. The piezoelectric vibrator according to any one of claims 1 to 6, wherein the reinforcing portion is spaced apart from the first bonding portion and the second bonding portion.

8. A first cavity larger than the vibrating portion in a plan view is provided on the piezoelectric vibrator side of the first substrate, and a second cavity larger than the vibrating portion in a plan view is provided on the piezoelectric vibrator side of the second substrate. The piezoelectric vibrator according to any one of claims 1 to 7.

9. The vibrating portion has a central portion where excitation electrodes are provided and a peripheral portion surrounding the central portion. An opening that opens to both the first substrate side and the second substrate side is provided between the central portion of the vibrating portion and the support arm. The piezoelectric vibrator according to any one of claims 1 to 8.

10. When the longitudinal direction of the opening in plan view is defined as the width direction, the support arm has a first side surface provided on one side in the width direction and a second side surface provided on the side opposite to the first side surface in the width direction. The opening has a first inner side surface provided on one side in the width direction and a second inner side surface provided on the side opposite to the first inner side surface in the width direction. The first side surface is located on the second inner side surface side with respect to the first inner side surface, and the second side surface is located on the first inner side surface side with respect to the second inner side surface. The piezoelectric vibrator according to claim 9.

11. On the piezoelectric vibration element side of the first substrate and the second substrate, a groove portion is provided in a part of a frame-shaped region surrounding the vibrating portion in plan view. The groove portion is provided so as to avoid a region overlapping with a portion where the support arm and the holding portion are connected in plan view. The piezoelectric vibrator according to any one of claims 1 to 10.

12. The material of the reinforcing portion is the same as the materials of the first bonding portion and the second bonding portion. The piezoelectric vibrator according to any one of claims 1 to 11.

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