Piezoelectric vibration piece and piezoelectric vibration device

Abstract

In the crystal vibration piece (10), the holding portion (13) has a pair of vibration holding portions (13a) parallel to a first virtual straight line (L1) passing through a top center point (C1) of the vibration portion (11) in the X-axis direction, and a pair of frame holding portions (13b) extending in the Z'-axis direction and connecting each vibration holding portion (13a) with two portions of the frame portion (12), each vibration holding portion (13a) connects the vibration portion (11) with the frame holding portion (13b), the frame holding portion (13b) connects the vibration holding portion (13a) with the frame portion (12), a first through hole (12g) is formed in the frame portion (12) and penetrates in the thickness direction, and the first through hole (12g) is located on the extension line of the frame holding portion (13b).

Description

Technical Field

[0001] The present invention relates to a piezoelectric vibrator and a piezoelectric vibrating device having the piezoelectric vibrator. Background Technology

[0002] Conventionally, piezoelectric vibrating devices suitable for miniaturization and thinning have been known as sandwich-structure piezoelectric vibrating devices. The housing of a sandwich-structure piezoelectric vibrating device is composed of an approximately cuboid encapsulation. This encapsulation consists of a first sealing member and a second sealing member, for example, made of glass or quartz crystal, and a piezoelectric vibrating plate with excitation electrodes formed on two main surfaces. The first and second sealing members are stacked and joined together with the piezoelectric vibrating plate in between. Furthermore, the vibrating portion of the piezoelectric vibrating plate disposed inside the encapsulation (internal space) is hermetically sealed by the first and second sealing members (see, for example, Patent Document 1).

[0003] In the piezoelectric vibrating device described in Patent Document 1, the piezoelectric vibrator employs a structure comprising a vibrating portion having an excitation electrode formed on its main surface, an outer frame portion surrounding the outer peripheral wall of the vibrating portion, a holding portion connecting the outer peripheral wall of the vibrating portion to the inner peripheral wall of the outer frame portion, and a hollow portion formed by hollowing out the space between the vibrating portion and the outer frame portion in the thickness direction. Furthermore, by providing only one holding portion, a structure is achieved that is both compatible with miniaturization and less susceptible to the effects of external stress transmitted from the outer frame portion and vibration leakage of the vibrating energy of the vibrating portion.

[0004] However, in recent years, to achieve high precision in piezoelectric vibratory devices, characteristic evaluation is required, one of which is acceleration sensitivity evaluation. This involves measuring not only the acceleration of the piezoelectric vibratory device vibrating at a specified frequency along its three axes (X, Y, and Z directions), but also the presence of any noise (spurious) signals. Therefore, piezoelectric vibratory devices that meet these characteristics are needed. However, when using a piezoelectric vibratory plate with only one holding part, the deflection in the thickness direction (Z direction) of the piezoelectric vibratory plate may increase, making it difficult to meet the requirements of acceleration sensitivity evaluation (e.g., G-sensitivity).

[0005] [Patent Documents] [Patent Document 1]: Japanese Patent Application Publication No. 2020-141358 Summary of the Invention

[0006] In view of the above, the object of the present invention is to provide a piezoelectric vibrating sheet that can suppress the influence of external stress and reduce the deflection in the thickness direction, and a piezoelectric vibrating device having the piezoelectric vibrating sheet.

[0007] As a technical solution to the above-mentioned technical problems, the present invention adopts the following structure. That is, the present invention is a piezoelectric vibrating plate that vibrates by a thickness shearing method, characterized in that: it employs a structure comprising a vibrating portion having an excitation electrode formed on its main surface, an outer frame portion surrounding the vibrating portion, a holding portion connecting the vibrating portion and the outer frame portion, and a hollow portion formed by hollowing out the space between the vibrating portion and the outer frame portion in the thickness direction. The holding portion has a pair of vibrating holding portions formed along a first virtual straight line passing through a first direction from the top view center point of the vibrating portion, and a pair of outer frame holding portions extending along a direction different from the first direction and connecting each vibrating holding portion to two parts of the outer frame portion. Each vibrating holding portion connects the vibrating portion to the outer frame holding portion, and the outer frame holding portion connects the vibrating holding portion to the outer frame portion. At least one of a through hole penetrating in the thickness direction and a thin-walled portion with a thinner thickness in the thickness direction is formed on the outer frame portion, and at least one of the through hole and the thin-walled portion is located on the extension line of the outer frame holding portion. More specifically, the present invention is a piezoelectric vibrator that vibrates by a thickness shearing method, characterized in that: it employs a structure comprising a vibrating portion having an excitation electrode formed on its main surface, an outer frame portion surrounding the outer peripheral wall of the vibrating portion, a holding portion connecting the outer peripheral wall of the vibrating portion to the inner peripheral wall of the outer frame portion, and a hollow portion formed by hollowing out the vibrating portion and the outer frame portion in the thickness direction. The holding portion has a pair of vibrating holding portions formed along a first virtual straight line passing through a first direction from the top view center point of the vibrating portion, and a pair of outer frame holding portions extending along a direction different from the first direction and connecting each vibrating holding portion to two portions of the inner peripheral wall of the outer frame portion. Each vibrating holding portion connects the outer peripheral wall of the vibrating portion to the outer frame holding portion, and the outer frame holding portion connects the vibrating holding portion to the inner peripheral wall of the outer frame portion. On the outer frame portion, at least one of a through hole penetrating in the thickness direction and a thin-walled portion with a thinner thickness in the thickness direction is formed, and at least one of the through hole and the thin-walled portion is located on the extension line of the outer frame holding portion.

[0008] Based on the above structure, a pair of vibration holding parts are connected to both ends of the vibrating part in the first direction, and outer frame holding parts extending in the second axis direction are connected to four parts of the outer frame part. Therefore, the influence of external stresses can be suppressed, and the deflection in the thickness direction of the piezoelectric vibrator can be reduced. Specifically, since the vibration holding parts are formed along a first virtual straight line passing through the first direction (e.g., the long side direction) from the top view center point of the vibrating part, the displacement of the vibrating part in the thickness direction can be effectively suppressed with a minimal number of points. Since the vibrating part is supported by vibration holding parts and outer frame holding parts extending in different directions, the displacement of the vibrating part in the first direction and directions other than the first direction can be effectively suppressed with a minimal number of points. Since the vibrating part is supported only by these two holding members—vibration holding parts and outer frame holding parts extending in different directions—there is no need to unnecessarily reduce the effective area of ​​the vibrating part.

[0009] Furthermore, since the vibration retaining portion is formed along a first virtual straight line connecting the top view center of the vibrating portion to the center of the extending direction of each outer frame retaining portion, the stress transmitted from the outer frame retaining portion to the vibrating portion is uniform, preventing stress from being transmitted to the vibrating portion in an unbalanced state. Additionally, the through-hole or thin-walled portion provided in the outer frame portion can impede the vibration transmission at the connection between the outer frame retaining portion and the outer frame portion, thereby reducing vibration leakage from the retaining portion (outer frame retaining portion) to the outer frame portion. Moreover, the through-hole or thin-walled portion can alleviate stress caused by external impacts, further reducing external stress transmitted from the outer frame portion to the retaining portion (outer frame retaining portion).

[0010] In the piezoelectric vibrator with the above structure, it is preferable that the outer frame retaining portion is configured to be symmetrical with respect to the first virtual straight line and symmetrical with respect to a second virtual straight line parallel to a second direction perpendicular to the first virtual straight line. Based on this structure, the stress transmitted from the outer frame portion to the vibration retaining portion can be made uniform, thereby preventing stress from being transmitted to the vibration retaining portion in an unbalanced state.

[0011] In the piezoelectric vibrator with the above structure, when the through hole is formed on the outer frame portion, it is preferable to form a through electrode on the inner wall surface of the through hole that conducts the main surfaces of the outer frame portion. Normally, when electrical wiring is formed on the inner peripheral wall of the outer frame portion, there is a possibility of wire breakage due to contact with the outside. However, by using the through electrode of the through hole as the electrical wiring, such wire breakage can be prevented.

[0012] In the piezoelectric vibrator having the above structure, when the thin-walled portion is formed on the outer frame portion, it is preferable that a wiring electrode passing through the step formed on the outer frame portion is formed on the thin-walled portion. Based on this structure, since the thin-walled portion is arranged between the outer frame holding portion and the outer frame portion, the wire breakage of the wiring electrode can be prevented by changing the shape of the step.

[0013] In the piezoelectric vibrator having the above structure, it is preferable that the piezoelectric vibrator is an AT-cut crystal vibrator. In the case of an AT-cut crystal vibrator, by extending the lead wire from the excitation electrode of the vibrating part along the X-axis direction, it is possible to prevent the lead wire from breaking.

[0014] Furthermore, the present invention relates to a piezoelectric vibrating device having a piezoelectric vibrating sheet with the above-described structure, characterized in that: an upper surface sealing sheet covering the upper surface side of the piezoelectric vibrating sheet and a lower surface sealing sheet covering the lower surface side of the piezoelectric vibrating sheet are joined to the piezoelectric vibrating sheet. Based on the piezoelectric vibrating device having the above-described structure, the same effects as those achieved with the piezoelectric vibrating sheet described above can be obtained.

[0015] <Invention Effects> Based on the piezoelectric vibrating sheet and piezoelectric vibrating device of the present invention, a pair of vibration holding portions are connected to both ends of the vibrating portion in the first direction, and outer frame holding portions extending in the second direction are connected to four parts of the outer frame portion, thereby suppressing the influence of external stress and reducing the deflection in the thickness direction of the piezoelectric vibrating sheet. Attached Figure Description

[0016] Figure 1 is a schematic diagram showing the outline structure of the crystal resonator according to this embodiment.

[0017] Figure 2 is a schematic top view of the first main surface side of the first sealing member of the crystal resonator.

[0018] Figure 3 is a schematic top view of the second main surface side of the first sealing member of the crystal resonator.

[0019] Figure 4 is a schematic top view of the first main surface of the crystal oscillator according to this embodiment.

[0020] Figure 5 is a schematic top view of the second main surface of the crystal oscillator according to this embodiment.

[0021] Figure 6 is a schematic top view of the first main surface side of the second sealing member of the crystal resonator.

[0022] Figure 7 is a schematic top view of the second main surface side of the second sealing member of the crystal resonator.

[0023] Figure 8 is a diagram corresponding to Figure 4 of the crystal oscillator according to other embodiments 1.

[0024] Figure 9 is a diagram corresponding to Figure 4 of the crystal oscillator according to other embodiments 2.

[0025] Figure 10 is a diagram corresponding to Figure 5 of the crystal oscillator according to other embodiments 2.

[0026] Figure 11 is a diagram corresponding to Figure 4 of the crystal oscillator according to other embodiments 3.

[0027] Figure 12 is a diagram corresponding to Figure 5 of the crystal oscillator according to other embodiments 3. Detailed Implementation

[0028] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Furthermore, the following embodiments will describe the case where the piezoelectric resonator of the present invention is a crystal resonator.

[0029] First, the basic structure of the crystal resonator 100 according to this embodiment will be described. As shown in FIG1, the crystal resonator 100 adopts a structure having a crystal vibrating plate (piezoelectric vibrating plate) 10, a first sealing member (upper surface sealing plate) 20, and a second sealing member (lower surface sealing plate) 30. In this crystal resonator 100, the crystal vibrating plate 10 is joined with the first sealing member 20 and the crystal vibrating plate 10 is joined with the second sealing member 30 to form an encapsulated body with an approximately rectangular sandwich structure. That is, in the crystal resonator 100, the internal space (cavity) of the encapsulated body is formed by joining the first sealing member 20 and the second sealing member 30 on the two main surfaces of the crystal vibrating plate 10, and the vibrating part 11 (see FIG4 and FIG5) is hermetically sealed in this internal space.

[0030] The crystal resonator 100 described in this embodiment has a package size of, for example, 1.0 × 0.8 mm, achieving miniaturization and thinness. Furthermore, the crystal resonator 100 is electrically connected to an external circuit board (not shown) via solder or the like.

[0031] Hereinafter, referring to FIGS. 1 to 7, each component of the crystal resonator 100, the first sealing member 20, and the second sealing member 30 will be described. Furthermore, the components of each individual structure that are not yet joined will be described here. FIGS. 2 to 7 merely show one structural example of each of the crystal resonator 10, the first sealing member 20, and the second sealing member 30, and are not intended to limit the present invention.

[0032] As shown in Figures 4 and 5, the crystal vibrator 10 is a piezoelectric substrate made of quartz crystal, and its two main surfaces (first main surface 101 and second main surface 102) are made into flat and smooth surfaces (mirror finish). In this embodiment, the crystal vibrator 10 is an AT-cut crystal sheet that performs thickness shear vibration. In the crystal vibrator 10 shown in Figures 4 and 5, the two main surfaces (101, 102) of the crystal vibrator 10 are XZ' planes. In this XZ' plane, the direction parallel to the short side direction of the crystal vibrator 10 is the X-axis direction, and the direction parallel to the long side direction of the crystal vibrator 10 is the Z' axis direction. In addition, AT cutting refers to a processing method in which the three crystal axes of artificial quartz crystal—electric axis (X-axis), mechanical axis (Y-axis), and optical axis (Z-axis)—are cut at an angle of approximately 35°15′ relative to the Z-axis around the X-axis. In the AT-cut crystal wafer, the X-axis coincides with the crystal axis of the quartz crystal. The Y' and Z' axes are approximately tilted by 35°15′ relative to the crystal axis of the quartz crystal (this cutting angle can be appropriately adjusted within the range of the frequency-temperature characteristics of the AT-cut crystal wafer). The Y' and Z' axis directions correspond to the cutting directions when the AT-cut crystal wafer is cut out. Furthermore, the cutting angles can be slightly adjusted according to the characteristics.

[0033] A pair of excitation electrodes (first excitation electrode 111, second excitation electrode 112) are formed on the two main surfaces (101, 102) of the crystal oscillator 10. The crystal oscillator 10 is configured to include a vibrating portion 11 that is configured to be approximately rectangular, an outer frame portion 12 surrounding the outer peripheral wall of the vibrating portion 11, a holding portion 13 connecting the outer peripheral wall of the vibrating portion 11 to the inner peripheral wall of the outer frame portion 12, and a hollow portion (14a, 14b) formed by hollowing out the space between the vibrating portion 11 and the outer frame portion 12 in the thickness direction. The inner peripheral wall of the outer frame portion 12 and the outer peripheral wall of the vibrating portion 11 are both configured to be rectangular in plan view. In addition, the plan view long side direction of the crystal oscillator 10 is arranged perpendicular to the plan view long side direction of the inner peripheral wall of the outer frame portion 12, and the plan view long side direction of the inner peripheral wall of the outer frame portion 12 is arranged in the same direction as the plan view long side direction of the vibrating portion 11. In the vibration section 11, the wall thickness on the outer periphery 11b side where the first excitation electrode 111 and the second excitation electrode 112 are not formed is greater than the wall thickness on the middle portion 11a side where the first excitation electrode 111 and the second excitation electrode 112 are formed, resulting in an annular height difference (step portion) 11c on the two main surfaces of the vibration section 11. A holding portion 13 is provided on both the +X direction side and the -X direction side of the vibration section 11. The holding portion 13 consists of a vibration holding portion 13a on the vibration section 11 side and an outer frame holding portion 13b on the outer frame portion 12 side. The detailed structure of the holding portion 13 will be described later.

[0034] A first excitation electrode 111 is disposed on the first main surface 101 side of the vibration section 11, and a second excitation electrode 112 is disposed on the second main surface 102 side of the vibration section 11. Input and output lead-out wires (lead-out electrodes) for connecting these excitation electrodes to external electrode terminals are connected to the first excitation electrode 111 and the second excitation electrode 112. A first lead-out wire 113 on the input side extends from the first excitation electrode 111 towards the +X direction, and is connected to a connection bonding pattern 12b formed on the first main surface 101 side of the outer frame section 12 via a holding portion 13 disposed on the +X direction side of the vibration section 11. The wall thickness of the outer frame section 12 is greater than the wall thickness of the holding portion 13, and there is a height difference between the outer frame section 12 and the holding portion 13. Therefore, the first lead-out wire 113 is connected to the connection bonding pattern 12b via an internal wiring 17 formed on the inner peripheral wall of the outer frame section 12. The internal wiring 17 is provided on the inner peripheral wall of the outer frame portion 12, which is parallel to the X-axis direction, i.e., on the inner peripheral wall on the +Z' direction side.

[0035] The second lead wire 114 on the output side extends from the second excitation electrode 112 toward the -X direction side and is connected to the connection pattern 12e formed on the second main surface 102 side of the outer frame portion 12 via the holding portion 13 provided on the -X direction side of the vibration portion 11. As described above, there is a height difference between the outer frame portion 12 and the holding portion 13, and the second lead wire 114 is connected to the connection pattern 12e via the internal wiring 18 formed on the inner peripheral wall of the outer frame portion 12. The connection pattern 12e is connected to the connection pattern 12a formed on the first main surface 101 side of the outer frame portion 12 via the through electrode of the second through hole 12h formed on the outer frame portion 12. The internal wiring 18 is provided on the inner peripheral wall of the outer frame portion 12 parallel to the X-axis direction, that is, on the inner peripheral wall on the -Z' direction side. In this embodiment, since the first lead wire 113 and the second lead wire 114 are led out in different directions, there will be no situation in the vibration section 11 where the lead wires are arranged facing each other across the vibration section 11. Therefore, it is possible to eliminate the useless excitation caused by the lead wires in the vibration section 11, thereby obtaining a structure with improved characteristic stability.

[0036] On the two main surfaces (first main surface 101 and second main surface 102) of the crystal oscillator 10, oscillator-side sealing portions for engaging the crystal oscillator 10 with the first sealing member 20 and the second sealing member 30 are respectively provided. The oscillator-side sealing portion of the first main surface 101 has a first engagement pattern 121 formed thereon; the oscillator-side sealing portion of the second main surface 102 has a second engagement pattern 122 formed thereon. The first engagement pattern 121 and the second engagement pattern 122 are provided on the outer frame portion 12 and are configured to be annular when viewed from above. The outer periphery of the first engagement pattern 121 is formed close to the outer periphery of the first main surface 101 of the crystal oscillator 10 (outer frame portion 12). The outer periphery of the second engagement pattern 122 is formed close to the outer periphery of the second main surface 102 of the crystal oscillator 10 (outer frame portion 12). The first bonding pattern 121 on the vibrating plate side and the second bonding pattern 122 on the vibrating plate side are connected via an internal wiring 19 formed on the inner peripheral wall of the outer frame portion 12. The internal wiring 19 is provided on the inner peripheral wall of the outer frame portion 12 that is parallel to the Z' axis direction, that is, on the inner peripheral wall on the -X direction side, that is, on the inner peripheral wall that is perpendicular to the inner peripheral wall on which the aforementioned internal wiring 17, 18 is provided.

[0037] Furthermore, as shown in Figures 4 and 5, five through holes are formed on the crystal oscillator 10, penetrating between the first main surface 101 and the second main surface 102. Specifically, four first through holes 12g are respectively provided in the four corner regions of the outer frame portion 12, and the four first through holes 12g are located on the extension line of the outer frame holding portion 13b of the holding portion 13. The second through hole 12h is provided on one side of the outer frame portion 12 in the Z' axis direction of the oscillator 11 (in Figures 4 and 5, it is the -Z' direction side). Around the four through holes 12g, a connecting pattern 12i is formed on the first main surface 101 side, and a connecting pattern 12j is formed on the second main surface 102 side. In addition, around the through hole 12h, a connecting pattern 12a is formed on the first main surface 101 side, and a connecting pattern 12e is formed on the second main surface 102 side.

[0038] In the first through-hole 12g and the second through-hole 12h, through electrodes for conducting electrodes formed on the first main surface 101 and the second main surface 102 are formed along the inner wall surface of each through-hole. Furthermore, the middle portion of each of the first through-hole 12g and the second through-hole 12h becomes a hollow through-hole that penetrates between the first main surface 101 and the second main surface 102. In this embodiment, an example with five through-holes penetrating between the first main surface 101 and the second main surface 102 is given. However, for example, as shown in FIG8, through-holes may not be formed, but a portion of the side surface of the crystal oscillator 10 may be cut off, and a crenellation wall 12k covering the electrodes may be formed on the inner wall surface of the cut-off area (the same applies to the first sealing member 20 and the second sealing member 30). In the example shown in Figure 8, the first lead wire 113 and the second lead wire 114 are formed on the holding portion 13 of the crystal oscillator 10, and no lead wires are formed on the first sealing member 20 and the second sealing member 30. Therefore, the first lead wire 113 and the second lead wire 114 can be led out along the shortest possible path. As a result, the length of the first lead wire 113 and the second lead wire 114 can be shortened, thereby reducing the parasitic capacitance caused therefrom.

[0039] As shown in Figures 2 and 3, the first sealing member 20 is a cuboid substrate made of an AT-cut crystal wafer. The second main surface 202 of the first sealing member 20 (the surface that engages with the crystal resonator 10) is made into a flat and smooth surface (mirror finish). Furthermore, although the first sealing member 20 does not have a vibrating part, by using the same AT-cut crystal wafer as the crystal resonator 10, the coefficient of thermal expansion of the crystal resonator 10 can be made the same as that of the first sealing member 20, thereby suppressing thermal deformation of the crystal resonator 100. In addition, the X-axis, Y-axis, and Z'-axis directions of the first sealing member 20 are also the same as those of the crystal resonator 10.

[0040] As shown in Figure 2, a first terminal 22 and a second terminal 23 for wiring, and a metal film 28 for shielding (grounding) are formed on the first main surface 201 (the outer main surface not facing the crystal oscillator 10) of the first sealing member 20. The first terminal 22 and the second terminal 23 for wiring are provided to electrically connect the first excitation electrode 111 and the second excitation electrode 112 of the crystal oscillator 10 to the external electrode terminal 32 of the second sealing member 30. The first terminal 22 and the second terminal 23 are provided at two ends in the Z' axis direction, with the first terminal 22 located on the +Z' direction side and the second terminal 23 located on the -Z' direction side. The first terminal 22 and the second terminal 23 are configured to extend in the X-axis direction. The first terminal 22 and the second terminal 23 are configured to be approximately rectangular.

[0041] A metal film 28 is disposed between the first terminal 22 and the second terminal 23, and is configured to be spaced apart from the first terminal 22 and the second terminal 23 by a predetermined interval. The metal film 28 is disposed over almost the entire area of ​​the first main surface 201 of the first sealing member 20 in the region where the first terminal 22 and the second terminal 23 are not formed. The metal film 28 is configured to extend from the +X end to the -X end of the first main surface 201 of the first sealing member 20.

[0042] As shown in Figures 2 and 3, six through holes are formed on the first sealing member 20, penetrating between the first main surface 201 and the second main surface 202. Specifically, four third through holes 211 are provided in the four corner (corner) regions of the first sealing member 20. Fourth through holes 212 and fifth through holes 213 are provided in the +Z' direction and Z' direction of Figures 2 and 3, respectively.

[0043] In the third through hole 211, the fourth through hole 212, and the fifth through hole 213, a through electrode is formed along the inner wall surface of each through hole to conduct the electrodes formed on the first main surface 201 and the second main surface 202. Furthermore, the middle portion of each of the third through hole 211, the fourth through hole 212, and the fifth through hole 213 forms a hollow through portion that penetrates between the first main surface 201 and the second main surface 202. Moreover, the through electrodes of the two third through holes 211 located diagonally opposite to each other on the first main surface 201 of the first sealing member 20 (the third through holes 211 located at the corners in the +X and +Z' directions in Figures 2 and 3, and the third through holes 211 located at the corners in the -X and -Z' directions) are electrically connected to each other through the metal film 28. Furthermore, the through electrode of the third through hole 211 located at the corner in the -X direction and the +Z' direction is electrically connected to the through electrode of the fourth through hole 212 via the first terminal 22. The through electrode of the third through hole 211 located at the corner in the +X direction and the -Z' direction is electrically connected to the through electrode of the fifth through hole 213 via the second terminal 23.

[0044] On the second main surface 202 of the first sealing member 20, a first sealing member-side engagement pattern 24 is formed as a first sealing portion for engaging with the crystal oscillator 10. The first sealing member-side engagement pattern 24 is configured to be annular when viewed from above. Additionally, on the second main surface 202 of the first sealing member 20, connection engagement patterns 25 are formed around the third through hole 211. Connection engagement patterns 261 are formed around the fourth through hole 212, and connection engagement patterns 262 are formed around the fifth through hole 213. The outer periphery of the first sealing member-side engagement pattern 24 is formed close to the outer periphery of the second main surface 202 of the first sealing member 20.

[0045] As shown in Figures 6 and 7, the second sealing member 30 is a cuboid substrate made of an AT-cut crystal wafer. The first main surface 301 of the second sealing member 30 (the surface that engages with the crystal oscillator 10) is configured as a flat and smooth surface (mirror finish). Furthermore, preferably, the second sealing member 30 also uses an AT-cut crystal wafer, just like the crystal oscillator 10, and the directions of the X-axis, Y-axis, and Z'-axis are the same as those of the crystal oscillator 10.

[0046] On the first main surface 301 of the second sealing member 30, a second sealing member-side engagement pattern 31 is formed as a second sealing portion for engaging with the crystal oscillator 10. The second sealing member-side engagement pattern 31 is configured to be annular when viewed from above. The outer periphery of the second sealing member-side engagement pattern 31 is formed to be close to the outer periphery of the first main surface 301 of the second sealing member 30.

[0047] On the second main surface 302 (the outer main surface not facing the crystal resonator 10) of the second sealing member 30, four external electrode terminals 32 are provided, which are electrically connected to an external circuit board disposed outside the crystal resonator 100. The external electrode terminals 32 are configured in an approximately L-shape and are located at the four corners (corners) of the second main surface 302 of the second sealing member 30. When viewed from above, the external electrode terminals 32 are positioned at a position overlapping with the outer frame portion 12 of the crystal resonator 10.

[0048] As shown in Figures 6 and 7, four through holes are formed on the second sealing member 30, penetrating between the first main surface 301 and the second main surface 302. Specifically, four sixth through holes 33 are provided in the four corner regions of the second sealing member 30. A through electrode for conducting electrodes formed on the first main surface 301 and the second main surface 302 is formed along the inner wall surface of each sixth through hole 33. Using the through electrodes formed on the inner wall surface of the sixth through holes 33, the electrodes formed on the first main surface 301 are connected to the external electrode terminals 32 formed on the second main surface 302. Furthermore, the middle portion of each sixth through hole 33 becomes a hollow through portion penetrating between the first main surface 301 and the second main surface 302. Additionally, connection patterns 34 are formed around the sixth through holes 33 on the first main surface 301 of the second sealing member 30. Additionally, a joining pattern 35 for connecting is formed on the first main surface 301 of the second sealing member 30.

[0049] In a crystal resonator 100 comprising a crystal oscillator 10, a first sealing member 20, and a second sealing member 30 having the aforementioned structure, the crystal oscillator 10 and the first sealing member 20 are diffusely bonded in a state where the first bonding pattern 121 on the oscillator side and the first bonding pattern 24 on the sealing member side overlap, and the crystal oscillator 10 and the second sealing member 30 are diffusely bonded in a state where the second bonding pattern 122 on the oscillator side and the second bonding pattern 31 on the sealing member side overlap, thereby forming a sandwich-structured package as shown in FIG1. ​​Thus, the internal space of the package, i.e., the accommodating space of the vibrating part 11, is hermetically sealed.

[0050] At this time, the aforementioned connection patterns also diffuse and bond with each other in an overlapping state. Furthermore, through the bonding of the connection patterns, electrical conduction is achieved in the crystal resonator 100 for the first excitation electrode 111, the second excitation electrode 112, and the external electrode terminal 32. Specifically, the first excitation electrode 111 is connected to the external electrode terminal 32 sequentially via the first lead wiring 113, the internal wiring 17, the connection pattern 12b, the connection pattern 261, the through electrode of the fourth through hole 212, the first terminal 22, the through electrode of the third through hole 211, the through electrode of the first through hole 12g, and the through electrode of the sixth through hole 33. The second excitation electrode 112 is connected to the external electrode terminal 32 sequentially via the second lead wiring 114, internal wiring 18, connection bonding pattern 12e, through electrode of the second through hole 12h, connection bonding pattern 12a, connection bonding pattern 262, through electrode of the fifth through hole 213, second terminal 23, through electrode of the third through hole 211, through electrode of the first through hole 12g, and through electrode of the sixth through hole 33. Additionally, the metal film 28 is grounded sequentially via the through electrode of the third through hole 211, the through electrode of the first through hole 12g, and the sixth through hole 33 (grounded using a portion of the external electrode terminal 32).

[0051] In the crystal resonator 100, preferably, the various bonding patterns are formed by stacking multiple layers on the crystal wafer, with Ti (titanium) and Au (gold) layers formed by evaporation or sputtering from the bottommost layer side. Furthermore, preferably, other wiring and electrodes formed on the crystal resonator 100 also employ the same structure as the bonding patterns, thus enabling simultaneous patterning of bonding patterns, wiring, and electrodes.

[0052] In the crystal resonator 100 configured as described above, the sealing portions (sealing paths 15 and 16) that hermetically seal the vibrating portion 11 of the crystal oscillator 10 are configured as annular from top view. Sealing path 15 is formed by diffusion bonding (Au-Au bonding) between the first bonding pattern 121 on the oscillator side and the first bonding pattern 24 on the sealing member side. The outer edge of sealing path 15 is configured to be approximately rectangular, and its outer periphery is positioned close to the outer periphery of the package. Similarly, sealing path 16 is formed by diffusion bonding (Au-Au bonding) between the second bonding pattern 122 on the oscillator side and the second bonding pattern 31 on the sealing member side. The outer edge of sealing path 16 is configured to be approximately rectangular, and its outer periphery is positioned close to the outer periphery of the package. Sealing path 15 is not electrically connected to the electrical conduction path between the first excitation electrode 111 and the external electrode terminal 32, and sealing path 16 is not electrically connected to the electrical conduction path between the second excitation electrode 112 and the external electrode terminal 32. Specifically, sealing path 15 is connected to sealing path 16 via internal wiring 19, and sealing path 16 is grounded via through electrode of through hole 33c (grounded using a portion of external electrode terminal 32).

[0053] In the crystal resonator 100 configured as described above, the sealing portions (sealing paths 15 and 16) that hermetically seal the vibrating portion 11 of the crystal oscillator 10 are configured as annular from top view. Sealing path 15 is formed by diffusion bonding (Au-Au bonding) between the first bonding pattern 121 on the oscillator side and the first bonding pattern 24 on the sealing member side. The outer edge of sealing path 15 is configured to be approximately rectangular, and its outer periphery is positioned close to the outer periphery of the package. Similarly, sealing path 16 is formed by diffusion bonding (Au-Au bonding) between the second bonding pattern 122 on the oscillator side and the second bonding pattern 31 on the sealing member side. The outer edge of sealing path 16 is configured to be approximately rectangular, and its outer periphery is positioned close to the outer periphery of the package.

[0054] In the crystal resonator 100, where sealing paths 15 and 16 are formed through diffusion bonding, there is a gap of less than 1.00 μm between the first sealing member 20 and the crystal oscillator 10, and a gap of less than 1.00 μm between the second sealing member 30 and the crystal oscillator 10. That is, the thickness of the sealing path 15 between the first sealing member 20 and the crystal oscillator 10 is less than 1.00 μm, and the thickness of the sealing path 16 between the second sealing member 30 and the crystal oscillator 10 is less than 1.00 μm (specifically, the Au-Au bonding in this embodiment is 0.15 μm to 1.00 μm). Furthermore, as a comparative example, in the case of using a conventional Sn-based metal paste sealing material, the thickness is 5 μm to 20 μm.

[0055] In this embodiment, the crystal oscillator 10 with the above-described structure has a holding portion 13 having a pair of vibration holding portions 13a and a pair of outer frame holding portions 13b. The pair of vibration holding portions 13a extend along a first virtual straight line L1 in a first direction (X-axis direction) passing through the top-view center point C1 of the oscillator 11. The pair of outer frame holding portions 13b extend in a direction different from the first direction (Z'-axis direction) and connect each vibration holding portion 13a to two portions of the inner peripheral wall of the outer frame portion 12. Each vibration holding portion 13a connects the outer peripheral wall of the oscillator 11 to the outer frame holding portion 13b, and the outer frame holding portion 13b connects the vibration holding portion 13a to the inner peripheral wall of the outer frame portion 12. A through hole penetrating in the thickness direction or a thin-walled portion with a thinner thickness in the thickness direction is formed on the outer frame portion 12. The through hole or thin-walled portion is located on the extension line of the outer frame holding portion 13b. This will be explained below with reference to FIG4.

[0056] As shown in Figure 4, on the +X and -X direction sides of the vibrating part 11, which is rectangular in plan view, there are retaining parts 13 configured to be approximately T-shaped in plan view. The retaining parts 13 are arranged symmetrically with respect to the first virtual line L1 and the second virtual line L2. Specifically, the retaining part 13 is formed by integrating a vibration retaining part 13a that extends linearly from the outer peripheral wall of the vibrating part 11 along the first virtual line L1 and an outer frame retaining part 13b that extends linearly parallel to the second virtual line L2. The first virtual line L1 is a straight line connecting the center point (center of gravity) C1 of the vibrating part 11 in plan view with the center of the extending direction (Z' axis direction) of each outer frame retaining part 13b.

[0057] Vibration holding part 13a and outer frame holding part 13b are connected in mutually perpendicular directions. Vibration holding part 13a extends along the long side of the inner peripheral wall of outer frame part 12 in plan view to the side of outer frame holding part 13b, and outer frame holding part 13b extends along the short side of the inner peripheral wall of outer frame part 12 in plan view to the side of inner peripheral wall of outer frame part 12. One end of vibration holding part 13a is connected to the middle portion of vibration part 11 in the Z' axis direction, and the other end of vibration holding part 13a is connected to the middle portion of outer frame holding part 13b in the Z' axis direction. Outer frame holding part 13b is connected to the four corner regions of the inner peripheral wall of outer frame part 12 in plan view. One end of outer frame holding part 13b is connected to the inner peripheral wall of outer frame part 12 on the +Z' direction side, and the other end of outer frame holding part 13b is connected to the inner peripheral wall of outer frame part 12 on the -Z' direction side.

[0058] Both the vibration holding portion 13a and the outer frame holding portion 13b are configured to be straight in plan view. The vibration holding portion 13a is configured to be wider and shorter in length in plan view compared to the outer frame holding portion 13b. Specifically, the length of the vibration holding portion 13a in the X-axis direction is less than the length of the outer frame holding portion 13b in the Z'-axis direction. The width of the vibration holding portion 13a in the Z'-axis direction is greater than the width of the outer frame holding portion 13b in the X-axis direction.

[0059] The retaining portion 13 with the above-described structure divides the hollow portion formed between the outer peripheral wall of the vibrating portion 11 and the inner peripheral wall of the outer frame portion 12 into multiple (four in this case) parts when viewed from above. Specifically, the hollow portion 14a is the part surrounded by the outer peripheral wall of the vibrating portion 11, the inner peripheral wall of the outer frame portion 12, the vibration retaining portion 13a of the retaining portion 13, and the outer frame retaining portion 13b, and is configured to have an approximate U-shape when viewed from above. The hollow portion 14b is the part surrounded by the inner peripheral wall of the outer frame portion 12 and the outer frame retaining portion 13b of the retaining portion 13, and is configured to be a straight line extending along the Z' axis when viewed from above.

[0060] Furthermore, as shown in FIG4, the first through holes 12g provided in the four corner regions of the outer frame portion 12 are located on the extension line of the outer frame retaining portion 13b of the retaining portion 13. In this embodiment, all four first through holes 12g are provided on the extension line of the outer frame retaining portion 13b of the retaining portion 13. The four first through holes 12g are provided in positions symmetrical with respect to the first virtual straight line L1 and symmetrical with respect to the second virtual straight line L2. However, the second through holes 12h are not provided on the extension line of the outer frame retaining portion 13b of the retaining portion 13.

[0061] Based on this embodiment, in the crystal oscillator 10, a pair of vibration holding portions 13a are connected to both ends of the oscillating portion 11 in the X-axis direction, and outer frame holding portions 13b extending in the Z'-axis direction are connected to four locations of the outer frame portion 12. Therefore, the influence of external stresses and the like can be suppressed, and the deflection in the thickness direction can be reduced. Specifically, by forming the vibration holding portions 13a along a first virtual straight line L1 passing through the first direction (here, the X-axis direction of the long side) from the top-view center point C1 of the oscillating portion 11, the displacement of the oscillating portion 11 in the thickness direction can be effectively suppressed with as few points as possible. By supporting the oscillating portion 11 with vibration holding portions 13a and outer frame holding portions 13b extending in different directions, the displacement of the oscillating portion 11 in the first direction and in directions different from the first direction can be effectively suppressed with as few points as possible. Since the oscillating portion 11 is supported only by these two holding members, vibration holding portions 13a and outer frame holding portions 13b extending in different directions, there is no need to unnecessarily reduce the effective area of ​​the oscillating portion 11. Furthermore, by forming the vibration holding portion 13a along the first virtual straight line L1 connecting the top view center point C1 of the vibration portion 11 to the center of the extending direction (Z' axis direction) of each outer frame holding portion 13b, the stress transmitted from the outer frame holding portion 13b to the vibration portion 11 can be made uniform, thereby preventing stress from being transmitted to the vibration portion 11 in an unbalanced state. Therefore, based on this embodiment, by adopting a structure in which the vibration portion 11 is indirectly connected to the outer frame portion 12 via the holding portion 13, and the vibration portion 11 is supported by four parts in the four corner regions of the outer frame portion 12, the requirements for acceleration sensitivity evaluation of the crystal oscillator 10 can be met without hindering miniaturization. Moreover, it can also provide a holding structure for the crystal oscillator 10 that ensures an effective top view area for the vibration portion 11, is not easily affected by external stress and vibration leakage, and has excellent overall balance performance.

[0062] Furthermore, the first through hole 12g is located on the extension line of the outer frame retaining portion 13b of the retaining portion 13. Therefore, the portion of the first through hole 12g can impede the vibration transmission of the connection between the outer frame retaining portion 13b and the outer frame portion 12, thereby reducing vibration leakage from the outer frame retaining portion 13b to the outer frame portion 12. Moreover, the portion of the first through hole 12g can alleviate stress caused by external impacts, thereby reducing external stress transmitted from the outer frame portion 12 to the outer frame retaining portion 13b.

[0063] Furthermore, if the electrical wiring is formed on the inner peripheral wall of the outer frame portion 12, there is a possibility of wire breakage due to contact with the outside. As described above, a through electrode is formed on the inner wall surface of the first through hole 12g to conduct the main surfaces of the outer frame portion 12. By using the through electrode of the first through hole 12g as an electrical wiring, such wire breakage can be prevented.

[0064] In this embodiment, the thickness of the outer frame portion 12 is greater than the thickness of the outer peripheral portion 11b of the vibrating portion 11, which in turn is greater than the thickness of the holding portion 13. One end of the holding portion 13 is connected to the middle portion of the outer peripheral portion 11b of the vibrating portion 11 in the thickness direction, and the other end of the holding portion 13 is connected to the middle portion of the inner peripheral wall of the outer frame portion 12 in the thickness direction. Thus, the holding portion 13 is sandwiched between the outer frame portion 12 (which is thicker than its wall) and the outer peripheral portion 11b of the vibrating portion 11, thereby improving the stress relief performance of the holding portion 13 in the thickness direction (Y-axis direction). Furthermore, since the vibrating portion 11, the holding portion 13, and the outer frame portion 12 are also symmetrical in the thickness direction (vertical direction), a structure can be achieved where the vibrating portion 11 does not easily skew even if it bends in the thickness direction.

[0065] Furthermore, the vibrating part 11 is an inverted frustum shape, and the thickness of the middle part 11a is thinner than that of the outer peripheral part 11b. The thickness of the outer frame part 12 > the thickness of the outer peripheral part 11b of the vibrating part 11 > the thickness of the holding part 13 ≥ the thickness of the middle part 11a of the vibrating part 11. Thus, by reducing the thickness of the middle part 11a of the vibrating part 11, higher frequencies can be accommodated; and the intensity of the vibrating part 11 can be increased using the outer peripheral part 11b of the vibrating part 11. By alternating the thinner portions (the middle part 11a and the holding part 13) that can accommodate higher frequencies with the thicker portions (the outer peripheral part 11b and the outer frame part 12) that can accommodate lower frequencies, leakage of the main vibration of the vibrating part 11 can be suppressed.

[0066] Furthermore, in this embodiment, the outer frame retaining portion 13b is configured to be symmetrical with respect to the first virtual straight line L1 passing through the top view center point C1 of the vibrating portion 11, and symmetrical with respect to the second virtual straight line L2 intersecting (perpendicular to) the first virtual straight line L1 passing through the top view center point C1 of the vibrating portion 11. This ensures that the stress transmitted from the outer frame portion 12 to the vibration retaining portion 13a is uniform, thereby preventing stress from being transmitted to the vibration retaining portion 13a in an unbalanced state. Moreover, by forming the vibration retaining portion 13a along the first virtual straight line L1 connecting the top view center point C1 of the vibrating portion 11 to the center of the extending direction (Z' axis direction) of each outer frame retaining portion 13b, the stress transmitted from the outer frame retaining portion 13b to the vibrating portion 11 is uniform, thereby preventing stress from being transmitted to the vibrating portion 11 in an unbalanced state.

[0067] In this embodiment, the inner peripheral wall of the outer frame portion 12 and the outer peripheral wall of the vibration portion 11 are both rectangular in plan view. The long side direction (Z' axis direction in this case) of the crystal vibrator 10 in plan view and the long side direction (X axis direction in this case) of the inner peripheral wall of the outer frame portion 12 in plan view are arranged in a direction perpendicular to each other. Each vibration holding portion 13a extends along the long side direction of the inner peripheral wall of the outer frame portion 12 in plan view to the side of the outer frame holding portion 13b, connecting the outer peripheral wall of the vibration portion 11 to the outer frame holding portion 13b. The outer frame holding portion 13b extends along the short side direction (Z' axis direction in this case) of the inner peripheral wall of the outer frame portion 12 in plan view to the side of the inner peripheral wall of the outer frame portion 12, connecting the inner peripheral wall of the outer frame portion 12 to the vibration holding portion 13a in the four corner areas of the inner peripheral wall of the outer frame portion 12 in plan view. Therefore, a wide region (regions at both ends in the Z' axis direction) is formed on both sides of the inner peripheral wall of the outer frame 12 in the long side direction when viewed from above, without hindering the miniaturization of the crystal oscillator 10, thus ensuring an effective area for wiring or bonding in this wide region. On the other hand, since a narrow region (regions at both ends in the X-axis direction) is formed on both sides of the inner peripheral wall of the outer frame 12 in the short side direction when viewed from above, the effective area of ​​the vibrating section 11 is ensured by providing such a narrow region.

[0068] Furthermore, since the vibration holding portion 13a, with fewer connection points and a small proprietary area when viewed from above, is arranged along the long side of the inner peripheral wall of the outer frame portion 12, the effective area of ​​the vibration portion 11 can be ensured, thereby facilitating the miniaturization of the crystal oscillator 10. Moreover, by arranging the outer frame holding portion 13b, with more connection points and a large proprietary area when viewed from above, along the short side of the inner peripheral wall of the outer frame portion 12, the length of the outer frame holding portion 13b can be shortened, thus ensuring the effective area of ​​the vibration portion 11 and facilitating the miniaturization of the crystal oscillator 10. In addition, since the outer frame holding portion 13b can be connected to a wide area of ​​the outer frame portion 12, it is beneficial to ensure strength against external impacts. Furthermore, since the outer frame holding portion 13b is connected to the four corner areas of the inner peripheral wall of the outer frame portion 12 when viewed from above, it is easy to reduce the deflection and stress of the outer frame portion 12 when subjected to external impacts, thereby facilitating stress relief.

[0069] In this embodiment, each vibration holding portion 13a and each outer frame holding portion 13b is formed as a straight line in plan view. Each vibration holding portion 13a and each outer frame holding portion 13b are connected in mutually perpendicular directions. Therefore, by making both the vibration holding portion 13a and the outer frame holding portion 13b straight lines, it is not necessary to unnecessarily enlarge the area of ​​the vibration holding portion 13a and the outer frame holding portion 13b, thus ensuring the effective area of ​​the vibration unit 11. Furthermore, well-balanced stress relief corresponding to the respective extending directions of the vibration holding portion 13a and the outer frame holding portion 13b can be achieved.

[0070] Furthermore, since one end of each vibration holding part 13a is connected to the middle portion of the opposing short side of the vibration part 11, the deflection of the vibration part 11 can be effectively reduced with fewer connection points. Since the other end of each vibration holding part 13a is connected to the middle portion of the outer frame holding part 13b, it is easy to maintain the balance of the holding part 13, thereby effectively reducing the deflection of the vibration part 11.

[0071] Furthermore, since each vibration holding part 13a is wider and shorter when viewed from above than the outer frame holding part 13b, the strength of the holding part 13 can be ensured without increasing the proprietary area when viewed from above by making the outer frame holding part 13b, which has many connection points, long and thin, and the vibration holding part 13a, which has few connection points, short and thick.

[0072] Furthermore, in this embodiment, a first lead wire 113 and a second lead wire 114 are formed, extending from the first excitation electrode 111 and the second excitation electrode 112 of the vibrating section 11 to the outer frame section 12 via the holding section 13. The vibration holding section 13a of the holding section 13 is connected to the X-axis end of the outer peripheral section 11b of the vibrating section 11. In the AT-cut crystal oscillator, a height difference (step) 11c is formed between the middle portion 11a and the outer peripheral section 11b of the vibrating section 11. Although a step is formed between the outer peripheral section 11b of the vibrating section 11 and the vibration holding section 13a of the holding section 13, the first lead wire 113 and the second lead wire 114 extend along the X-axis direction, where the slope of the step is gentler than that of the Z' axis, thus preventing the first lead wire 113 and the second lead wire 114 from breaking. In addition, the vibration holding part 13a is a narrower area, and it is more difficult to form the required wiring compared with the outer frame holding part 13b. However, since the first lead wire 113 and the second lead wire 114 extend along the X-axis direction, it is possible to prevent the first lead wire 113 and the second lead wire 114 from breaking.

[0073] The crystal resonator 100 equipped with the crystal oscillator 10 described above can also achieve the same functions and effects as the crystal oscillator 10. That is, it can suppress the influence of external stress and reduce the deflection in the thickness direction of the crystal oscillator 10. In addition, since the internal wiring 17 is not exposed on the outer surface of the package of the crystal resonator 100, it is possible to avoid the occurrence of breakage or wear of the internal wiring 17 due to collisions during assembly or transportation.

[0074] The embodiments disclosed herein are merely illustrative of all aspects and should not be construed as limiting. Therefore, the technical scope of this invention cannot be interpreted solely based on the above embodiments and must be defined according to the claims. Furthermore, all modifications of the same meaning and scope as those in the claims are included.

[0075] The number of the first through holes 12g described above is only one example. For example, three or fewer first through holes 12g may be formed on the outer frame portion 12. In the above embodiment, all four first through holes 12g are located on the extension line of the outer frame holding portion 13b, but it is not limited to this. It may also be configured such that at least one first through hole 12g is located on the extension line of the outer frame holding portion 13b.

[0076] The shape and number of the vibration retaining part 13a and the outer frame retaining part 13b described above are only one example, and various modifications can be made. For example, the vibration retaining part 13a can be configured as a trapezoid, and the width of the vibration part 11 side can be smaller than the width of the outer frame retaining part 13b side. Alternatively, the outer frame retaining part 13b can be configured as a V-shape bent at a predetermined angle, or as an arc or an elliptical arc. In this case, the end of the outer frame retaining part 13b is connected to the corner of the inner peripheral wall of the outer frame part 12, and the retaining part 13 is configured as an approximately Y-shape. In addition, the number of each connection point (connection point) of the vibration retaining part 13a and the outer frame retaining part 13b is even, preferably, the number of connection points of the outer frame retaining part 13b is a multiple of the number of connection points of the vibration retaining part 13a.

[0077] In the above embodiment, the thickness of the vibration holding portion 13a of the holding portion 13 is the same as the thickness of the outer frame holding portion 13b, but it is also possible that the thickness of the vibration holding portion 13a is different from the thickness of the outer frame holding portion 13b. Furthermore, in the above embodiment, the thickness T3 of the holding portion 13 is thicker than the thickness T1 of the middle portion 11a of the vibration portion 11, but it is also possible that the thickness T3 of the holding portion 13 is the same as the thickness T1 of the middle portion 11a of the vibration portion 11.

[0078] In the above embodiment, a first through hole (through hole) 12g is provided on the extension line of the outer frame holding portion 13b of the outer frame portion 12. However, as shown in Figures 9 and 10, thin-walled portions (12m, 12n) with a thinner thickness in the thickness direction can also be formed on the extension line of the outer frame holding portion 13b of the outer frame portion 12. Specifically, on the first main surface 101 side of the crystal oscillator 10, as shown in Figure 9, thin-walled portions 12m are continuously formed at both ends in the Z' axis direction of the outer frame holding portion 13b. The thin-walled portions 12m are configured to be approximately triangular in plan view, and connecting patterns 12a and 12b are formed on the surface of the thin-walled portions 12m. The thin-walled portions 12m are provided at four locations on the outer frame portion 12 where the outer frame holding portion 13b connects to the inner peripheral wall of the outer frame portion 12. The four thin-walled portions 12m have the same shape. Four thin-walled sections 12m are positioned symmetrically with respect to the first virtual straight line L1 (see Figure 4) and symmetrically with respect to the second virtual straight line L2 (see Figure 4).

[0079] On the second main surface 102 side of the crystal oscillator 10, as shown in FIG10, thin-walled portions 12n are continuously formed at both ends in the Z' axis direction of the outer frame retaining portion 13b. The thin-walled portions 12n are configured to be approximately triangular in plan view, and connecting patterns 12e and 12f are formed on the surface of the thin-walled portions 12n. The thin-walled portions 12n are provided at four locations on the outer frame portion 12 where the outer frame retaining portion 13b connects to the inner peripheral wall of the outer frame portion 12. The four thin-walled portions 12n have the same shape. The four thin-walled portions 12n are positioned symmetrical with respect to the first virtual straight line L1 (see FIG4) and symmetrical with respect to the second virtual straight line L2 (see FIG4).

[0080] By providing thin-walled portions (12m, 12n) on the outer frame portion 12 as described above, the thin-walled portions (12m, 12n) can be used to impede the vibration transmission of the connection between the outer frame retaining portion 13b and the outer frame portion 12, thereby reducing vibration leakage from the outer frame retaining portion 13b to the outer frame portion 12. Furthermore, the thin-walled portions (12m, 12n) can alleviate stress caused by external impacts, thereby reducing external stress transmitted from the outer frame portion 12 to the outer frame retaining portion 13b. Additionally, since wiring electrodes passing through steps formed on the outer frame portion 12 are formed in the thin-walled portions (12m, 12n), and by arranging the thin-walled portions (12m, 12n) between the outer frame retaining portion 13b and the outer frame portion 12, the wiring electrode breakage can be prevented by changing the step shape (changing the axial direction of the step).

[0081] The shape and number of the aforementioned thin-walled portions (12m, 12n) are merely examples; for instance, no more than three thin-walled portions 12m and no more than three thin-walled portions 12n may be formed on the outer frame portion 12. Furthermore, the shape of the thin-walled portions (12m, 12n) may be approximately rectangular or semi-circular. In the examples shown in Figures 9 and 10, all four thin-walled portions 12m and four thin-walled portions 12n are located on the extension line of the outer frame retaining portion 13b, but this is not a limitation; it is also possible for at least one thin-walled portion 12m and at least one thin-walled portion 12n to be located on the extension line of the outer frame retaining portion 13b. Additionally, in the examples shown in Figures 9 and 10, thin-walled portions (12m, 12n) are provided on both the first main surface 101 side and the second main surface 102 side of the outer frame portion 12, but it is also possible for thin-walled portions to be provided only on either the first main surface 101 side or the second main surface 102 side of the outer frame portion 12. Furthermore, in the examples shown in Figures 9 and 10, a shape with a height difference between the thin-walled portions (12m, 12n) and the outer frame retaining portion 13b is used. However, a structure without a height difference where the thin-walled portions (12m, 12n) and the outer frame retaining portion 13b are located on the same plane can also be used. Additionally, in the examples shown in Figures 9 and 10, a first through hole 12g is provided on the outer frame portion 12 along with a thin-walled portion (12m, 12n). However, it is also possible to omit the first through hole 12g on the outer frame portion 12 and only provide the thin-walled portion (12m, 12n); or, as in the above embodiment, the thin-walled portion (12m, 12n) is omitted from the outer frame portion 12, and only the first through hole 12g is provided (see Figures 4 and 5).

[0082] In the above embodiments, the long side direction of the crystal oscillator 10 in plan view may also be aligned with the long side direction of the vibrating part 11 in plan view. For example, as shown in Figures 11 and 12, the crystal oscillator 10 and the vibrating part 11 are configured as a rectangle in plan view, with both the long side direction of the crystal oscillator 10 and the long side direction of the vibrating part 11 being parallel to the X-axis direction. In the examples of Figures 11 and 12, the X-axis direction and Z'-axis direction of the crystal oscillator 10 are 90 degrees different from those in the above embodiments, and the X-axis direction and Z'-axis direction are interchanged, but the rest of the structure of the crystal oscillator 10 is the same as in the above embodiments. For example, in the examples of Figures 11 and 12, the vibration holding part 13a of the holding part 13 extends along the Z'-axis direction, and the outer frame holding part 13b extends along the X-axis direction. In addition, wide regions (regions at both ends in the X-axis direction) are formed on both sides of the inner peripheral wall of the outer frame portion 12 in the long side direction when viewed from above, and narrow regions (regions at both ends in the Z' axis direction) are formed on both sides of the inner peripheral wall of the outer frame portion 12 in the short side direction when viewed from above.

[0083] Thus, by making the long side direction of the crystal oscillator 10 and the long side direction of the oscillating part 11 parallel to the X-axis direction, the top view area of ​​the hollowed-out part 14a formed between the oscillating part 11, the outer frame part 12, and the holding part 13 can be minimized as much as possible, thereby maximizing the top view area of ​​the oscillating part 11 and ensuring that the vibration area of ​​the oscillating part 11 is sufficiently large. Furthermore, internal wiring 17 is provided on the inner peripheral wall of the outer frame part 12 extending along the Z' axis direction, i.e., the inner peripheral wall on the +X direction side; internal wiring 18 is provided on the inner peripheral wall of the outer frame part 12 extending along the Z' axis direction, i.e., the inner peripheral wall on the -X direction side. Thus, internal wiring 17 and internal wiring 18 are provided on the X-axis end face of the hollowed-out part 14a. Here, if the cutout portion 14a is formed by wet etching, due to the anisotropy of the AT-cut crystal wafer, the X-axis end face of the cutout portion 14a is continuously formed with multiple inclined surfaces that are gentler than the Z'-axis end face. Therefore, by forming the internal wiring 17 and internal wiring 18 on such an X-axis end face, the film thickness of the internal wiring 17 and internal wiring 18 can be ensured, thereby preventing the internal wiring 17 and internal wiring 18 from breaking.

[0084] Furthermore, since the vibration holding portion 13a extends along a direction perpendicular to the vibration direction (X-axis direction) of the thickness shear vibration of the vibration portion 11 (Z'-axis direction), the sensitivity to the frequency response to external vibrations can be reduced, thereby suppressing frequency fluctuations. Here, if the vibration holding portion 13a extends along the vibration direction (X-axis direction) of the thickness shear vibration of the vibration portion 11, the vibration portion 11 is prone to displacement due to external vibrations, leading to capacitance fluctuations and potentially increasing frequency fluctuations. This embodiment avoids such problems.

[0085] In the above embodiments, the width of the vibration holding portion 13a of the holding portion 13 (the width in the direction perpendicular to the extending direction of the vibration holding portion 13a) may be greater than the distance (gap) between the vibration portion 11 of the hollow portion 14a and the outer frame holding portion 13b. For example, in the example of FIG11, the width W1 of the vibration holding portion 13a connected to the +Z' direction side of the vibration portion 11 in the X-axis direction is greater than the distance D1 between the vibration portion 11 of the hollow portion 14a and the outer frame holding portion 13b (W1 > D1). In addition, the width W2 of the vibration holding portion 13a connected to the -Z' direction side of the vibration portion 11 in the X-axis direction is greater than the distance D2 between the vibration portion 11 of the hollow portion 14a and the outer frame holding portion 13b (W2 > D2). The widths W1 and W2 are the same (W1 = W2). Distances D1 and D2 are the lengths of each vibration holding part 13a in the Z' axis direction (the lengths of the vibration holding part 13a in the extension direction), and distances D1 and D2 are the same (D1 = D2). Through this relationship, the widths W1 and W2 of the vibration holding part 13a at the part where the holding part 13 is connected to the vibration part 11 can be maximized, thereby increasing the strength of the holding part 13.

[0086] In the above embodiment, an AT-cut crystal vibrator was used as the piezoelectric vibrator, but other piezoelectric vibrators that perform thickness shear vibration can also be used.

[0087] In the above embodiments, the first sealing member 20 and the second sealing member 30 are made of crystal sheets, but they are not limited to this. For example, the first sealing member 20 and the second sealing member 30 can also be made of glass or resin.

[0088] In the above embodiment, the number of external electrode terminals 32 on the second main surface 302 of the second sealing member 30 is four, but it is not limited to this. For example, the number of external electrode terminals 32 may also be two, six, or eight. Furthermore, the application of the present invention to a crystal resonator 100 has been described, but it is not limited to this. The present invention may also be applied to piezoelectric oscillators such as crystal oscillators. In the case of piezoelectric oscillators, as described above, by using the shortest possible path to lead out the first lead wire 113 and the second lead wire 114 (see Figure 8), parasitic capacitance can be reduced, thereby ensuring a large frequency variable range for the piezoelectric oscillator and improving its performance, especially effective in VCXOs (voltage-controlled piezoelectric oscillators).

[0089] In the above embodiment, as an electrical connection path from a pair of excitation electrodes (first excitation electrode 111 and second excitation electrode 112) formed on the crystal oscillator 10 to the external electrode terminal 32 of the second main surface 302 of the second sealing member 30, a through hole is provided to penetrate the second sealing member 30, and is constituted by a through electrode in the through hole. However, it is not limited to this. The present invention is also applicable to a structure in which a crenellated wall is provided on the outer end face of the second sealing member 30, and the electrical connection is realized by the outer end electrode in the crenellated wall.

[0090] This application claims priority based on Japanese Patent Application 2024-57035, filed on March 29, 2024. It is self-evident that all contents of that application are incorporated herein by reference.

[0091] <Explanation of Figure Labels> 10. Crystal resonator (piezoelectric resonator) 11 Vibrating section 12 Outer Frame 12g First through hole (through hole) 12m, 12n thin-walled section 13. Maintenance Section 13a Vibration retention section 13b Outer frame retaining part 14a, 14b Openwork sections 20. First sealing component (upper surface sealing plate) 30. Second sealing component (lower surface sealing plate) 100 Crystal Resonator (Piezoelectric Vibration Device) 111 First excitation electrode 112 Second excitation electrode L1 First Virtual Line L2 Second Virtual Line

Claims

1. A piezoelectric vibrating plate that vibrates by thickness shearing, characterized in that: The structure comprises a vibrating part having an excitation electrode formed on its main surface, an outer frame part surrounding the vibrating part, a holding part connecting the vibrating part and the outer frame part, and a hollow part formed by hollowing out the space between the vibrating part and the outer frame part in the thickness direction. The retaining portion has a pair of vibration retaining portions formed along a first virtual straight line in a first direction passing through the top view center point of the vibration portion, and a pair of frame retaining portions extending in a direction different from the first direction and connecting each vibration retaining portion to two parts of the outer frame portion. Each vibration holding part connects the vibration part to the outer frame holding part, and the outer frame holding part connects the vibration holding part to the outer frame part. On the outer frame portion, at least one of a through hole extending in the thickness direction and a thin-walled portion with a thinner thickness in the thickness direction is formed, and at least one of the through hole and the thin-walled portion is located on the extension line of the outer frame holding portion.

2. The piezoelectric vibrating sheet as described in claim 1, characterized in that: The outer frame retaining portion is configured to be symmetrical with respect to the first virtual straight line and symmetrical with respect to the second virtual straight line that is parallel to the second direction perpendicular to the first virtual straight line.

3. The piezoelectric vibrating sheet as described in claim 1, characterized in that: When the through hole is formed on the outer frame portion, a through electrode is formed on the inner wall surface of the through hole to make the inner and outer main surfaces of the outer frame portion conductive.

4. The piezoelectric vibrating sheet as described in claim 1, characterized in that: When the thin-walled portion is formed on the outer frame portion, a wiring electrode passing through the step formed on the outer frame portion is formed on the thin-walled portion.

5. The piezoelectric vibrating sheet as described in claim 1, characterized in that: This piezoelectric vibrator is an AT-cut crystal vibrator.

6. A piezoelectric vibration device comprising the piezoelectric vibrating plate according to any one of claims 1 to 5, characterized in that: The upper surface sealing sheet covering the upper surface of the piezoelectric vibrator and the lower surface sealing sheet covering the lower surface of the piezoelectric vibrator are joined to the piezoelectric vibrator.

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