Piezoelectric Devices

Abstract

A piezoelectric device 11 comprises: a piezoelectric element 20; a package 30 that incorporates at least the piezoelectric element 20; and a vibration absorber 60 that supports the package 30 in a mounting member 50 for mounting the package 30, and that absorbs vibrations transmitted from the mounting member 50 to the package 30. The piezoelectric element 20 is a crystal vibration element that is substantially rectangular in plan view and that comprises: a quartz strip 27 having a first main surface 21 and a second main surface 22 in a front-to-back relationship; and electrodes 23, 24 that extend from the first main surface 21 to the second main surface 22 of the quartz strip 27.

Description

[Technical Field]

[0001] The present disclosure relates to a piezoelectric device including a piezoelectric element. [Background technology]

[0002] Piezoelectric devices that house a piezoelectric element in a package are widely used. Piezoelectric devices that include a piezoelectric element and an electronic element are also widely used. Examples of these piezoelectric devices include SPXOs (Simple Packaged Crystal Oscillators), VCXOs (Voltage Controlled Crystal Oscillators), TCXOs (Temperature Compensated Crystal Oscillators), and OCXOs (Oven Controlled Crystal Oscillators).

[0003] Furthermore, piezoelectric devices in which the piezoelectric element is doubly sealed using two packages are also known. For example, Patent Document 1 discloses a piezoelectric device in which a piezoelectric element and an electronic element are housed in a first package, and the first package is further housed in a second package. Patent Document 2 discloses a piezoelectric device in which a piezoelectric element is housed in a first package, and the first package and an electronic element are further housed in a second package. In this type of piezoelectric device, the first package housing the piezoelectric element is isolated from the surrounding atmosphere by the second package, making it difficult for temperature changes in the surrounding atmosphere to reach the piezoelectric element, thereby stabilizing the oscillation frequency. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2019-153849 [Patent Document 2] Japanese Patent Application Publication No. 2019-153851 Summary of the Invention

[0005] The piezoelectric device according to the present disclosure comprises: a piezoelectric element; before The piezoelectric element is built in first The package and an electronic element that drives the piezoelectric element; a second package further incorporating the electronic element and the first package; The aforementioned second package Within The aforementioned first Supporting the package, the second package From the above first A vibration absorber that absorbs vibrations transmitted to the package, Equipped with The aforementioned first The package mounts the piezoelectric element. first a substrate and the piezoelectric element first Hermetically sealed with the substrate first a lid body, the first substrate of the first package includes a first main surface and a second main surface which are opposite surfaces, the piezoelectric element is mounted on the first main surface which corresponds to the inner surface of the first substrate, and the electronic element is mounted on the second main surface which corresponds to the outer surface of the first substrate; the second package includes a second base on which the first package is mounted via the vibration absorber, and a second lid that hermetically seals the electronic element and the first package together with the second base, The vibration absorber has a first main surface and a second main surface which are opposite sides of the vibration absorber, and the second main surface of the vibration absorber is first The above-mentioned package first The vibration absorber is fixed to the outer surface of the cover, and the first main surface of the vibration absorber is The inner surface of the second substrate of the second package is fixed at. [Brief explanation of the drawings]

[0006] [Figure 1] 1 is a perspective view showing a piezoelectric device according to a first embodiment. [Figure 2] FIG. 2 is a cross-sectional view taken along line II-II in FIG. [Figure 3] FIG. 1 is an exploded perspective view showing a piezoelectric device according to a first embodiment. [Figure 4] FIG. 2 is an exploded perspective view showing the inside of a package in the piezoelectric device of the first embodiment. [Figure 5] FIG. 10 is a perspective view showing a piezoelectric device according to a second embodiment. [Figure 6] FIG. 6 is a cross-sectional view taken along line VI-VI in FIG. 5. [Figure 7] FIG. 10 is an exploded perspective view showing a piezoelectric device according to a second embodiment. [Figure 8] FIG. 10 is an exploded perspective view showing the inside of a first package of the piezoelectric device according to the second embodiment. [Figure 9] FIG. 10 is a cross-sectional view showing a piezoelectric device according to a third embodiment. [Figure 10] FIG. 10 is a cross-sectional view showing a piezoelectric device according to a fourth embodiment. [Figure 11] FIG. 10 is a cross-sectional view showing a piezoelectric device according to a fifth embodiment. [Figure 12] FIG. 10 is a cross-sectional view showing a piezoelectric device according to a sixth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0007] Hereinafter, a description will be given of an embodiment (hereinafter referred to as an "embodiment") of the present disclosure with reference to the accompanying drawings. In this specification and the drawings, substantially identical components are designated by the same reference numerals, and redundant explanations will be omitted. Shapes depicted in the drawings are given priority for clarity and ease of drawing, and therefore do not necessarily correspond to actual dimensions and proportions.

[0008] <Embodiment 1> A piezoelectric device 11 according to a first embodiment will be described with reference to Figs. 1 to 4. In Figs. 1 and 3, the mounting member 50 is shown cut away. In Fig. 4, a portion of the base 30a is shown cut away. The internal structure of the package 30 (such as the piezoelectric element 20) is shown only in Figs. 2 and 4.

[0009] The piezoelectric device 11 comprises a piezoelectric element 20, a package 30 incorporating at least the piezoelectric element 20, and a vibration absorber 60 that supports the package 30 on a mounting member 50 that mounts the package 30 and absorbs vibrations transmitted from the mounting member 50 to the package 30.

[0010] Piezoelectric element 20 is a quartz crystal vibrating element that has a substantially rectangular shape in a plan view and includes quartz crystal blank 27 having first and second principal surfaces 21 and 22 that are opposite each other, and electrodes 23 and 24 that extend from first principal surface 21 to second principal surface 22 of quartz crystal blank 27. Quartz crystal blank 27 is made of, for example, an AT-cut plate. Electrodes 23 and 24 are insulated from each other and are divided into excitation electrodes, extraction electrodes, pad electrodes, etc., and extend from first principal surface 21 across the side surfaces to second principal surface 22.

[0011] An AC voltage is applied to the crystal blank 27 via electrodes 23 and 24. This causes thickness-shear vibration in the crystal blank 27, causing the first principal surface 21 and the second principal surface 22 to move apart, generating a specific oscillation frequency. In this way, the piezoelectric element 20 operates to output a signal at a constant oscillation frequency based on the piezoelectric effect and inverse piezoelectric effect of the crystal blank 27.

[0012] The piezoelectric element 20 is a thickness shear vibration element, but a tuning fork-type bending vibration element or a contour shear vibration element may be used instead. Note that a piezoelectric element made of ceramics may be used instead of a quartz vibration element. The planar shape of the piezoelectric element 20 is not limited to a square shape and may be any shape, such as a circle, an ellipse, or a polygon.

[0013] The package 30 includes a base 30a on which the piezoelectric element 20 is mounted, and a lid 30b that is bonded to the base 30a to hermetically seal the piezoelectric element 20. The package 30 in the first embodiment is a piezoelectric resonator, but may also be an SPXO, VCXO, TCXO, or OCXO. The three-dimensional shape of the package 30 is not limited to a rectangular parallelepiped shape, and may be, for example, a cylindrical shape or an elliptical cylindrical shape.

[0014] The base 30a includes a substrate portion 33 on which the piezoelectric element 20 is mounted, and a frame portion 34 located on the periphery of the substrate portion 33. The substrate portion 33 has a first main surface 31 and a second main surface 32, which are opposite sides of each other, a pair of piezoelectric element pads 36, 37 provided on the first main surface 31, and external terminals 38 provided at four corners of the second main surface 32. The frame portion 34 is provided in a rectangular frame shape on the periphery of the first main surface 31 of the substrate portion 33. The inside of the package 30 is a recessed space 35 surrounded by the substrate portion 33 and the frame portion 34. The electrodes 23, 24 of the piezoelectric element 20 and the piezoelectric element pads 36, 37 are electrically connected by bonding materials 25, 26, such as conductive adhesive.

[0015] The substrate 33 and frame 34 are made of, for example, a laminated ceramic plate formed by stacking and firing a plurality of green sheets. The piezoelectric element pads 36, 37 and the external terminals 38 are electrically connected to each other by internal wiring (not shown) formed in the substrate 33 and frame 34. The internal wiring is made of, for example, a conductor pattern or via-hole conductors printed on the green sheets. The piezoelectric element pads 36, 37 and the external terminals 38 are made of, for example, a surface Au (gold) layer and an underlying Ni (nickel) layer.

[0016] The lid 30b is a rectangular flat plate having a first main surface 41 and a second main surface 42, which face each other. The lid 30b is made of a material such as a metal such as Kovar or ceramics. The lid 30b is joined to the base 30a by electric welding or glass sealing, and hermetically seals the recessed space 35. The lid 30b and the external terminals 38 are electrically connected by internal wiring (not shown) formed in the substrate portion 33 and the frame portion 34.

[0017] The mounting member 50 is a component within an electronic device on which the piezoelectric device 11 is mounted, and has a main surface 51 and package pads 52. An example of the mounting member 50 is a printed wiring board. A printed wiring board is a synthetic resin board on which lands and a wiring pattern (not shown) are formed using copper foil or the like. The package pads 52 are provided on the main surface 51 at positions corresponding to the external terminals 38 of the package 30. The package pads 52 and the external terminals 38 are electrically connected by wires 53. The wires 53 are made of a metal such as gold or aluminum and are flexible. A common wire bonding technique is used to connect the wires 53. The package pads 52 are electrically connected to predetermined locations by wiring patterns (not shown) formed on the main surface 51, inside, or back surface of the mounting member 50. Alternatively, the mounting member 50 may be made of a multilayer ceramic plate or the like.

[0018] The vibration absorber 60 is a rectangular flat plate having a first main surface 61 and a second main surface 62, which are opposite surfaces. The material of the vibration absorber 60 may be any material capable of absorbing vibrations transmitted from the mounting member 50 to the package 30. A suitable material for the vibration absorber 60 is a gel-like material, particularly a silicone-based gel (polymer gel composition). Silicon-based gel is a moderately soft gel-like material primarily made of silicone, and is commercially available under the trademark αGEL (registered trademark). When the vibration absorber 60 is a silicone-based gel, the silicone-based gel is processed into a rectangular flat plate, and the second main surface 62 is fixed to the package 30 via an adhesive, and the first main surface 61 is fixed to the mounting member 50 via an adhesive. An acrylic adhesive is suitable as the adhesive. The planar shape of the vibration absorber 60 is not limited to a rectangular shape and may be any shape, such as a circle, an ellipse, or a polygon. The number of vibration absorbers 60 is also not limited to one, and multiple vibration absorbers may be used.

[0019] Next, a method for assembling the piezoelectric device 11 will be described.

[0020] First, as shown in Fig. 4, bonding materials 25, 26 made of a conductive adhesive are applied to the piezoelectric element pads 36, 37 on the first main surface 31 of the substrate portion 33. Then, the electrodes 23, 24 of the piezoelectric element 20 are placed on the bonding materials 25, 26, and heat treatment is performed at a predetermined temperature for a predetermined time to harden the bonding materials 25, 26. As a result, the piezoelectric element 20 is fixed in a cantilevered state on the substrate portion 33. Then, the recessed space 35 of the base body 30a is sealed with the lid body 30b, and the package 30 is completed.

[0021] 3, the package 30 is turned upside down (with the lid 30b side facing down) from the state shown in FIG. 4 (with the lid 30b side facing up), and the package 30 is fixed onto the main surface 51 of the mounting member 50 via the vibration absorber 60.

[0022] 1, the external terminals 38 of the package 30 are connected to the package pads 52 of the mounting member 50 by wires 53. In this way, the piezoelectric device 11 is mounted on the mounting member 50.

[0023] Next, the operation and effects of the piezoelectric device 11 will be described. The inventors conducted repeated experiments and studies in an effort to further stabilize the oscillation frequency of piezoelectric devices. As a result, they discovered that minute vibrations (e.g., wind from a cooling fan or vibrations from a cooling fan) from a mounting member (e.g., a printed wiring board) affect the oscillation frequency of the piezoelectric device. This effect is believed to be due to the direct piezoelectric effect (voltage generation due to pressure) of the piezoelectric element. The present disclosure is based on this finding. Specifically, by inserting a vibration absorber 60 between the mounting member 50 and the package 30, the vibrations of the mounting member 50 are absorbed by the vibration absorber 60, thereby suppressing vibrations transmitted from the mounting member 50 to the package 30. Therefore, the piezoelectric device 11 can achieve further stabilization of the oscillation frequency.

[0024] <Embodiment 2> The piezoelectric device 12 of the second embodiment will be described with reference to Figs. 5 to 8. Fig. 5 shows the state before the lid 80b is bonded to the base 80a, with a portion of the base 80a cut away. Fig. 7 shows a portion of the lid 80b and a portion of the base 80a cut away. Fig. 8 shows a portion of the base 130a cut away. First Package 130 The internal structure (piezoelectric element 20, etc.) is shown only in FIGS.

[0025] The piezoelectric device 12 includes a piezoelectric element 20, an electronic element 70 that drives the piezoelectric element 20, a first package 130 that houses the piezoelectric element 20 and the electronic element 70, a second package 80 that further houses the first package 130, and a vibration absorber 60 that supports the first package 130 within the second package 80 and absorbs vibrations transmitted from the second package 80 to the first package 130. The following description will focus on differences from the first embodiment. The piezoelectric element 20 is the same as the piezoelectric element in the first embodiment, so a description thereof will be omitted.

[0026] The first package 130 includes a base 130a on which the electronic element 70 and the piezoelectric element 20 are mounted, and a lid 130b that is bonded to the base 130a to hermetically seal the electronic element 70 and the piezoelectric element 20. The first package 130 in the second embodiment is a TCXO, but may also be a VCXO or OCXO. The three-dimensional shapes of the first package 130 and the second package 80 are not limited to a rectangular parallelepiped shape and may be, for example, a cylindrical shape or an elliptical cylindrical shape.

[0027] The base 130a includes a substrate portion 133 on which the electronic element 70 is mounted, a first frame portion 134a located on the periphery of the substrate portion 133 and on which the piezoelectric element 20 is mounted, and a second frame portion 134b located on the periphery of the first frame portion 134a. The substrate portion 133 has a first main surface 131a and a second main surface 132, which are opposite each other, a plurality of electronic element pads 139 provided on the first main surface 131a, and external terminals 138 provided at each of the four corners of the second main surface 132. The first frame portion 134a has a main surface 131b and a pair of piezoelectric element pads 136, 137 provided on the main surface 131b. The first frame portion 134a is formed in a rectangular frame shape on the periphery of the first main surface 131a of the substrate portion 133, and the second frame portion 134b is formed in a rectangular frame shape on the periphery of the main surface 131b of the first frame portion 134a. The inside of the first package 130 is a recessed space 135 surrounded by a substrate portion 133, a first frame portion 134a, and a second frame portion 134b. The electrodes 23, 24 of the piezoelectric element 20 and the piezoelectric element pads 136, 137 are electrically connected by bonding materials 25, 26 such as conductive adhesive.

[0028] The substrate portion 133, the first frame portion 134a, and the second frame portion 134b are made of, for example, a laminated ceramic plate formed by stacking and firing multiple green sheets. The piezoelectric element pads 136, 137, the external terminals 138, and the electronic element pads 139 are electrically connected to one another by internal wiring (not shown) formed in the substrate portion 133, the first frame portion 134a, and the second frame portion 134b. The internal wiring is made of, for example, a conductor pattern or via-hole conductors printed on the green sheets. The piezoelectric element pads 136, 137, the external terminals 138, and the electronic element pads 139 are made of, for example, a surface Au layer and an underlying Ni layer.

[0029] The lid 130b is a rectangular flat plate having a first main surface 141 and a second main surface 142, which face each other. The lid 130b is made of a material such as a metal such as Kovar or ceramics. The lid 130b is joined to the base 130a by electric welding or glass sealing, and hermetically seals the recessed space 135. The lid 130b and the external terminal 138 are electrically connected by internal wiring (not shown) formed in the substrate portion 133, the first frame portion 134a, and the second frame portion 134b.

[0030] The electronic element 70 is an IC having the function of a temperature sensor 71 and the function of an oscillation circuit of the piezoelectric element 20. (Integrated Circuit) The electronic element 70 is a flip chip (FC) in which the connection terminals 72 are bumps. The bumps are made of, for example, gold or solder and are electrically connected to the electronic element pads 139. The same number of connection terminals 72 and electronic element pads 139 are provided. That is, the electronic element 70 is mounted face-down on the base 130a via the connection terminals 72, with the circuit-forming surface including the connection terminals 72 of the electronic element 70 facing the electronic element pads 139 on the first main surface 131a. The temperature sensor 71 utilizes the forward voltage of a p-n junction formed in, for example, an IC. The forward voltage of this p-n junction decreases as the temperature increases. Therefore, voltage information can be obtained by passing a constant current through the p-n junction and measuring the forward voltage. Temperature information of the electronic element 70 and, ultimately, the piezoelectric element 20 can be obtained by converting the voltage information. The electronic element 70 may be a temperature sensor only, such as a thermistor or diode, or may be a resin-molded product or packaged product, not limited to an FC. The connection terminals 72 may be formed using wires made of aluminum or gold instead of bumps.

[0031] The second package 80 includes a base 80a on which the first package 130 is mounted, and a lid 80b that hermetically seals the first package 130 by being joined to the base 80a.

[0032] The base 80a includes a substrate 83 on which the first package 130 is mounted, a first frame 84a located on the periphery of the substrate 83, and a second frame 84b located on the periphery of the first frame 84a. The substrate 83 has a first main surface 81a and a second main surface 82, which are opposite each other, and external terminals 88 provided at four corners of the second main surface 82. The first frame 84a has a main surface 81b and package pads 86 provided on the main surface 81b. The first frame 84a is provided in a rectangular frame shape on the periphery of the first main surface 81a of the substrate 83, and the second frame 84b is provided in a rectangular frame shape on the periphery of the main surface 81b of the first frame 84a. The second package 80 includes a recessed space 85 surrounded by the substrate 83, the first frame 84a, and the second frame 84b. The external terminals 138 of the first package 130 and the package pads 86 are electrically connected by wires 87. The wires 87 are made of a metal such as gold or aluminum and are flexible. The wires 87 are connected using a general wire bonding technique.

[0033] The substrate portion 83, the first frame portion 84a, and the second frame portion 84b are made of, for example, a laminated ceramic plate formed by stacking and firing a plurality of green sheets. The package pads 86 and the external terminals 88 are electrically connected to each other by internal wiring (not shown) formed in the substrate portion 83, the first frame portion 84a, and the second frame portion 84b. The internal wiring is made of, for example, a conductor pattern or via-hole conductors printed on the green sheets. The package pads 86 and the external terminals 88 are made of, for example, an Au layer on the surface and an Ni layer underneath.

[0034] The lid 80b is a rectangular flat plate having a first main surface 91 and a second main surface 92, which face each other. The lid 80b is made of a material such as a metal such as Kovar or ceramics. The lid 80b is joined to the base 80a by electric welding or glass sealing, and hermetically seals the recessed space 85. The lid 80b and the external terminals 88 are electrically connected by internal wiring (not shown) formed in the substrate portion 83, the first frame portion 84a, and the second frame portion 84b.

[0035] The vibration absorber 60 is similar to the vibration absorber in embodiment 1, but the first main surface 61 is fixed to the first main surface 81a of the second package 80 via an adhesive, and the second main surface 62 is fixed to the first package 130 via an adhesive.

[0036] Next, a method for assembling the piezoelectric device 12 will be described.

[0037] 8, the surface of the electronic element 70 on which the connection terminals 72 are formed is faced toward the first main surface 131a in the recessed space 135, the pads 139 for the electronic element are aligned with the connection terminals 72, and the connection terminals 72 are pressed against the pads 139 for the electronic element while heat or ultrasonic waves are applied. As a result, the connection terminals 72 are bonded to the pads 139 for the electronic element, and the electronic element 70 is mounted in the first package 130.

[0038] Next, bonding materials 25, 26 made of a conductive adhesive are applied to the piezoelectric element pads 136, 137 on the main surface 131b of the first frame portion 134a. Then, the electrodes 23, 24 of the piezoelectric element 20 are placed on the bonding materials 25, 26, and heat treatment is performed at a predetermined temperature for a predetermined time to harden the bonding materials 25, 26. As a result, the piezoelectric element 20 is fixed in a cantilever shape on the first frame portion 134a, and the piezoelectric element 20 is mounted in the first package 130.

[0039] Next, the recessed space 135 of the base body 130a is sealed with the lid body 130b, and the first package 130 is completed.

[0040] 7, the first package 130 is turned upside down (with the lid 130b side facing down) from the state shown in Fig. 8 (with the lid 130b side facing up). Then, the first package 130 is fixed onto the first main surface 81a inside the second package 80 via the vibration absorber 60.

[0041] 5, the external terminals 138 of the first package 130 and the package pads 86 of the second package 80 are connected by wires 87. In this way, the first package 130 is mounted inside the second package 80.

[0042] Finally, the recessed space 85 of the second package 80 is sealed with the lid 80b, and the piezoelectric device 12 is completed.

[0043] Piezoelectric device 12 configured as described above is mounted on the surface of a printed wiring board that constitutes an electronic device by fixing the bottom surfaces of external terminals 88 to the printed wiring board by soldering, Au bumps, conductive adhesive, etc. Piezoelectric device 12 is used as an oscillation source in various electronic devices, such as personal computers, watches, game consoles, communication devices, and in-vehicle devices such as car navigation systems.

[0044] Next, the function and effect of the piezoelectric device 12 will be described.

[0045] Piezoelectric device 12 has a structure in which piezoelectric element 20 and electronic element 70 are housed in a first package 130, and first package 130 is further housed in a second package 80. Therefore, according to piezoelectric device 12, first package 130, which houses piezoelectric element 20 and electronic element 70, is isolated from the surrounding atmosphere by second package 80, making it difficult for temperature changes in the surrounding atmosphere to reach piezoelectric element 20 and electronic element 70, thereby stabilizing the oscillation frequency.

[0046] In addition, by inserting the vibration absorber 60 between the second package 80 and the first package 130, the vibration of the second package 80 is absorbed by the vibration absorber 60, thereby suppressing vibration transmitted from the second package 80 to the first package 130. Therefore, with the piezoelectric device 12, these effects combine to achieve further stabilization of the oscillation frequency. In particular, the piezoelectric device 12 is significantly effective against sudden temperature changes and vibrations caused by wind from a cooling fan. The other configurations, actions, and effects of the second embodiment are the same as those of the first embodiment.

[0047] <Embodiment 3> The piezoelectric device 13 of the third embodiment will be described with reference to Fig. 9. The cross section shown in Fig. 9 corresponds to the cross sections shown in Figs. 2 and 6. As can be seen from these correspondences, the piezoelectric device 13 of the third embodiment has many parts in common with the piezoelectric device 11 of the first embodiment (Fig. 2) and the piezoelectric device 12 of the second embodiment (Fig. 6). Therefore, the first package 30 will be designated by the reference numeral of the package 30 (Fig. 2) of the first embodiment, and the second package 80 will be designated by the reference numeral of the second package 80 (Fig. 6) of the second embodiment.

[0048] The piezoelectric device 13 comprises a piezoelectric element 20, a first package 30 incorporating the piezoelectric element 20, an electronic element 70 that drives the piezoelectric element 20, a second package 80 that further incorporates the electronic element 70 and the first package 30, and a vibration absorber 60 that supports the first package 30 within the second package 80 and absorbs vibrations transmitted from the second package 80 to the first package 30.

[0049] The first package 30 has a first base 30a on which the piezoelectric element 20 is mounted, and a first lid 30b that hermetically seals the piezoelectric element 20 together with the first base 30a. The second package 80 has a second base 80a on which the electronic element 70 is mounted and on which the first package 30 is mounted via a vibration absorber 60, and a second lid 80b that hermetically seals the electronic element 70 and the first package 30 together with the second base 80a.

[0050] The piezoelectric device 13 differs from the piezoelectric device 12 of the second embodiment (FIG. 6) in that the electronic element 70 is mounted on the first main surface 81a of the second package 80, rather than in the first package 30. In the third embodiment, pads 89 for the electronic element are formed on the first main surface 81a, and the electronic element 70 and the first package 30 are arranged side by side on the first main surface 81a.

[0051] According to the piezoelectric device 13, the electronic element 70 and the first package 30 are arranged side by side on the first main surface 81a, so that the conditions for heat conduction via the first main surface 81a are the same for the electronic element 70 and the first package 30. Therefore, the temperature sensor 71 in the electronic element 70 can measure the temperature of the piezoelectric element 20 in the first package 30 more accurately, thereby improving the temperature compensation accuracy. The other configurations, actions, and effects of the third embodiment are the same as those of the first and second embodiments. Therefore, the piezoelectric device 13 According to the present invention, these effects work together to achieve even greater stabilization of the oscillation frequency.

[0052] <Embodiment 4> A piezoelectric device 14 of embodiment 4 will be described with reference to Fig. 10. In this embodiment 4, as in embodiment 3, the first package 30 will be designated by the same reference numeral as the package 30 in embodiment 1 (Fig. 2), and the second package 80 will be designated by the same reference numeral as the second package 80 in embodiment 2 (Fig. 6).

[0053] The piezoelectric device 14 comprises a piezoelectric element 20, a first package 30 incorporating the piezoelectric element 20, an electronic element 70 that drives the piezoelectric element 20, a second package 80 that further incorporates the electronic element 70 and the first package 30, and a vibration absorber 160 that supports the first package 30 within the second package 80 and absorbs vibrations transmitted from the second package 80 to the first package 30.

[0054] The first package 30 has a first base 30a on which the piezoelectric element 20 is mounted, and a first lid 30b that hermetically seals the piezoelectric element 20 together with the first base 30a. The second package 80 has a second base 80a on which the electronic element 70 is mounted and on which the first package 30 is mounted via a vibration absorber 160, and a second lid 80b that hermetically seals the electronic element 70 and the first package 30 together with the second base 80a.

[0055] The piezoelectric device 14 differs from the piezoelectric device 12 of the third embodiment (FIG. 9) in that the electronic element 70 and the first package 30 overlap in plan view. The vibration absorber 160 is divided into two parts along two opposing sides of the first package 30 in plan view, with a first main surface 161 fixed to the first main surface 81a of the second package 80 via an adhesive, and a second main surface 162 fixed to the first package 30 via an adhesive. The height of the vibration absorber 160 is made larger than the height of the electronic element 70 mounted on the first main surface 81a, so that the electronic element 70 can be inserted between the pair of vibration absorbers 160. Vibration absorber 160 The material etc. of the vibration absorber 160 is the same as the material etc. of the vibration absorber in embodiment 1. The vibration absorbers 160 may be provided at the four corners of the first package 30 in plan view.

[0056] According to the piezoelectric device 14, the electronic element 70 and the first package 30 overlap in plan view, which reduces the area occupied by the piezoelectric device 14, thereby contributing to the miniaturization of electronic devices incorporating the piezoelectric device 14. 4 The other configurations, actions, and effects are the same as those of the first to third embodiments.

[0057] <Embodiment 5> A piezoelectric device 15 of embodiment 5 will be described with reference to Fig. 11. In embodiment 5, as in embodiment 3, the first package 30 will be designated by the same reference numeral as the package 30 in embodiment 1 (Fig. 2), and the second package 80 will be designated by the same reference numeral as the second package 80 in embodiment 2 (Fig. 6).

[0058] The piezoelectric device 15 comprises a piezoelectric element 20, a first package 30 incorporating the piezoelectric element 20, an electronic element 70 that drives the piezoelectric element 20, a second package 80 that further incorporates the electronic element 70 and the first package 30, and a vibration absorber 60 that supports the first package 30 within the second package 80 and absorbs vibrations transmitted from the second package 80 to the first package 30.

[0059] The first package 30 includes a first main surface 31 and a second main surface 32, which are opposite surfaces, and has a first base 30a on which a piezoelectric element 20 is mounted on the first main surface 31 and an electronic element 70 is mounted on the second main surface 32, and a first lid 30b that hermetically seals the piezoelectric element 20 together with the first base 30a. The second package 80 has a second base 80a on which the first package 30 is mounted via a vibration absorber 60, and a second lid 80b that hermetically seals the electronic element 70 and the first package 30 together with the second base 80a. Connection terminals 72 of the electronic element 70 are electrically connected to electronic element pads 39 provided on the second main surface 32 of the first base 30a.

[0060] Piezoelectric device 15 differs from piezoelectric device 14 of embodiment 4 (FIG. 10) in that piezoelectric element 20 is mounted on first main surface 31 of first package 30 and electronic element 70 is mounted on second main surface 32. Vibration absorber 60 is similar to the vibration absorber of embodiment 1, but first main surface 61 is fixed to first main surface 81a of second package 80 via adhesive, and second main surface 62 is fixed to first package 30 via adhesive.

[0061] In the piezoelectric device 15, the electronic element 70 is mounted on the first package 30 supported by the vibration absorber 60, so that not only vibrations transmitted from the second package 80 to the first package 30 but also vibrations transmitted from the first package 30 to the electronic element 70 are suppressed by the vibration absorber 60. Therefore, the piezoelectric device 15 can suppress malfunction of the electronic element 70 and extend the life of the electronic element 70, and these effects combine to achieve further stabilization of the oscillation frequency. This embodiment 5 The other configurations, actions, and effects are the same as those of the first to fourth embodiments.

[0062] <Embodiment 6> A piezoelectric device 16 of embodiment 6 will be described with reference to Fig. 12. In embodiment 6, as in embodiment 3, the first package 30 will be designated by the same reference numeral as the package 30 in embodiment 1 (Fig. 2), and the second package 80 will be designated by the same reference numeral as the second package 80 in embodiment 2 (Fig. 6).

[0063] The piezoelectric device 16 comprises a piezoelectric element 20, a first package 30 incorporating the piezoelectric element 20, an electronic element 70 that drives the piezoelectric element 20, a second package 80 that further incorporates the electronic element 70 and the first package 30, and a vibration absorber 260 that supports the first package 30 within the second package 80 and absorbs vibrations transmitted from the second package 80 to the first package 30.

[0064] The first package 30 has a first base 30a on which the piezoelectric element 20 is mounted and a first lid 30b that hermetically seals the piezoelectric element 20 together with the first base 30a. The second package 80 has a second base 80a on which the electronic element 70 is mounted, with the first package 30 fixed via a vibration absorber 260, and a second lid 80b that hermetically seals the electronic element 70 and the first package 30 together with the second base 80a. The vibration absorber 260 has a first main surface 261 fixed to the electronic element 70 via an adhesive and a second main surface 262 fixed to the first package 30 via an adhesive. The materials and the like of the vibration absorber 260 are the same as those of the vibration absorber in the first embodiment.

[0065] The piezoelectric device 16 differs from the piezoelectric device 14 of the third embodiment (FIG. 9) in that the vibration absorber 260 is not between the first package 30 and the first main surface 81a, but is between the first package 30 and the electronic element 70. According to the piezoelectric device 16, the electronic element 70 and the vibration absorber 260 are disposed between the second package 80 and the first package 130. 260 By inserting the vibration absorber 260, vibrations of the second package 80 are attenuated by the electronic element 70 and then absorbed by the vibration absorber 260, thereby further suppressing vibrations transmitted from the second package 80 to the first package 130. Therefore, the piezoelectric device 16 can more reliably achieve further stabilization of the oscillation frequency. The other configurations, actions, and effects of the sixth embodiment are the same as those of the first to fourth embodiments.

[0066] <Other> Although the present disclosure has been described above with reference to the above-described embodiments, the present disclosure is not limited to the above-described embodiments. Various modifications that would be understood by a person skilled in the art can be made to the details of the configuration of the present disclosure. The present disclosure also includes appropriate combinations of part or all of the configurations of the above-described embodiments. [Industrial Applicability]

[0067] The present disclosure can be used as a piezoelectric device. [Explanation of symbols]

[0068] 11,12,13,14,15,16 Piezoelectric devices 20 Piezoelectric element 21 First principal surface 22 Second principal surface 23,24 electrode 25,26 Bonding material 27 Crystal piece 30 packages (first package) 30a Base (first base) 31 First principal surface 32 Second principal surface 33 Circuit board section 34 Frame 35 Recessed space 36,37 Piezoelectric element pad 38 External terminal 39 Pads for electronic elements 30b Lid body (first lid body) 41 First principal surface 42 Second principal surface 50 Mounting materials 51 Main Surface 52 Package pad 53 Wire 60,160,260 Vibration absorber 61,161,261 First principal surface 62,162,262 Second principal surface 70 Electronic Elements 71 Temperature Sensor 72 Connection terminal 80 Second Package 80a Base (second base) 81a First principal surface 81b Main surface 82 Second principal surface 83 Circuit Board 84a First frame 84b Second frame part 85 Recessed space 86 Package pad 87 Wire 88 External terminal 89 Pads for electronic elements 80b Lid body (second lid body) 91 First principal surface 92 Second principal surface 130 First Package 130a Base 131a First principal surface 131b Main surface 132 Second principal surface 133 Circuit Board 134a First frame 134b Second frame part 135 Recessed space 136,137 Piezoelectric element pad 138 External terminal 139 Pads for electronic elements 130b Lid body 141 First principal surface 142 Second principal surface

Claims

1. a piezoelectric element; a first package incorporating the piezoelectric element; an electronic element that drives the piezoelectric element; a second package further incorporating the electronic element and the first package; a vibration absorber that supports the first package within the second package and absorbs vibrations transmitted from the second package to the first package; Equipped with the first package includes a first base on which the piezoelectric element is mounted, and a first lid that hermetically seals the piezoelectric element together with the first base, the first substrate of the first package includes a first main surface and a second main surface which are opposite surfaces, the piezoelectric element is mounted on the first main surface which corresponds to the inner surface of the first substrate, and the electronic element is mounted on the second main surface which corresponds to the outer surface of the first substrate; the second package includes a second base on which the first package is mounted via the vibration absorber, and a second lid that hermetically seals the electronic element and the first package together with the second base, The vibration absorber has a first main surface and a second main surface which are opposite sides of the surface, the second main surface of the vibration absorber is fixed to the outer surface of the first lid of the first package, and the first main surface of the vibration absorber is fixed to the inner surface of the second base of the second package.

2. The vibration absorber is made of a gel material. The piezoelectric device according to claim 1 .

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