Piezoelectric vibrator

Abstract

The present invention provides a piezoelectric vibrator, the frequency precision of which is adjustable after encapsulation.　A piezoelectric vibrator (1) comprises: a piezoelectric vibration element (10) having a vibrating part (110) and excitation electrodes (14a, 14b) respectively provided on upper and lower surfaces of the vibrating part (110); an upper substrate layer (20) provided on the upper-surface side of the piezoelectric vibration element (10); a lower substrate layer (30) provided on the lower-surface side of the piezoelectric vibration element (10); first resin bonding materials (X1, X2) provided between the upper substrate layer (20) and the lower substrate layer (30), and along an outer periphery in a plan view; and a first protective film (F1) having light-shielding properties against irradiating light (R) of a prescribed wavelength for cleaning the excitation electrodes (14a, 14b), said film being provided on the upper substrate layer (20) and / or the lower substrate layer (30) in an area overlapping the first resin bonding materials (X1, X2) in a plan view.

Description

Piezoelectric vibrator

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

[0002] Piezoelectric vibrators are known, each of which has a piezoelectric vibration element disposed inside a sealed package. The piezoelectric vibrator has a pair of excitation electrodes on the top and bottom surfaces of the vibrating part, and the piezoelectric vibrator oscillates at a constant frequency using the piezoelectric effect. Piezoelectric vibrators are used as timing devices, sensors, oscillators, and other applications in various electronic devices, such as mobile communication terminals, communication base stations, and home appliances.

[0003] Patent Document 1 describes that by externally irradiating oxygen plasma or ultraviolet light onto the piezoelectric vibration element inside the package, organic matter in the internal space of the package is reduced and a decrease in the degree of vacuum is prevented.

[0004] JP 2009-021773 A

[0005] However, in the piezoelectric vibrator described in Patent Document 1, for example, when the internal space after sealing is cleaned by ultraviolet irradiation, the ultraviolet rays may hit the resin bonding material used in the package, causing organic matter to be generated, which may deteriorate the sealing ability of the package or cause frequency fluctuations.

[0006] The present disclosure has been made in view of the above circumstances, and aims to provide a piezoelectric vibrator whose frequency accuracy can be adjusted after sealing.

[0007] A piezoelectric vibrator according to one aspect of the present disclosure comprises a piezoelectric vibration element having a vibration portion and excitation electrodes respectively provided on the upper and lower surfaces of the vibration portion, an upper substrate layer provided on the upper surface side of the piezoelectric vibration element, a lower substrate layer provided on the lower surface side of the piezoelectric vibration element, a first resin bonding material provided between the upper substrate layer and the lower substrate layer along the outer periphery in a planar view, and a first protective film that is provided on at least one of the upper substrate layer and the lower substrate layer in an area that overlaps with the first resin bonding material in a planar view and that is light-blocking against irradiation light of a predetermined wavelength that cleans the excitation electrode.

[0008] According to the present invention, it is possible to provide a piezoelectric vibrator whose frequency accuracy can be adjusted after sealing.

[0009] FIG. 1 is an exploded perspective view of a piezoelectric vibrator according to a first embodiment. FIG. 2 is a plan view of the piezoelectric vibrator according to the first embodiment from above. FIG. 3 is a cross-sectional view of the piezoelectric vibrator according to the first embodiment taken along line III-III. FIG. 4 is a cross-sectional view of the piezoelectric vibrator according to the first embodiment. FIG. 5 is an exploded perspective view of a piezoelectric vibrator according to a second embodiment. FIG. 6 is a plan view of the piezoelectric vibrator according to the second embodiment from above. FIG. 7 is a cross-sectional view of the piezoelectric vibrator according to the second embodiment taken along line VII-VII. FIG. 8 is a cross-sectional view of the piezoelectric vibrator according to the second embodiment.

[0010] The following describes an embodiment of the present invention. The drawings of the embodiment are merely examples, and the dimensions and shapes of each part are schematic, so the technical scope of the present invention should not be interpreted as being limited to the embodiment.

[0011] First Embodiment A piezoelectric vibrator 1 according to a first embodiment will be described with reference to Fig. 1 to Fig. 4. Fig. 1 is an exploded perspective view of the piezoelectric vibrator 1 according to the first embodiment.

[0012] The piezoelectric vibrator 1 includes a piezoelectric vibration element 10, an upper substrate layer 20, a lower substrate layer 30, and an external electrode T. For example, as shown in Fig. 1, the piezoelectric vibrator 1 has a structure in which the lower substrate layer 30, the piezoelectric vibration element 10, and the upper substrate layer 20 are stacked in the thickness direction. In the piezoelectric vibrator 1, the upper substrate layer 20 and the lower substrate layer 30 face each other with the piezoelectric vibration element 10 sandwiched therebetween.

[0013] The piezoelectric vibrator 1 has a sealed package structure in which the upper substrate layer 20 and the lower substrate layer 30 are bonded to each other at the top and bottom surfaces of the piezoelectric vibration element 10 by a resin bonding material X1 provided on the outer periphery of the upper substrate layer 20 and a resin bonding material X2 provided on the outer periphery of the lower substrate layer 30, thereby forming a vibration space inside in which the vibration part of the piezoelectric vibration element 10 vibrates.

[0014] The external electrode T includes a power supply terminal for applying a drive voltage to the piezoelectric vibration element 10. The external electrode T may also include a ground terminal for applying a reference potential to the piezoelectric vibration element 10. The external electrode T may also include a dummy terminal for balancing electrical characteristics such as capacitance and mechanical strength.

[0015] The piezoelectric vibration element 10 is an electromechanical energy conversion element that converts electrical energy into mechanical energy and vice versa by the piezoelectric effect.

[0016] The piezoelectric vibration element 10 includes a vibration part 110 and excitation electrodes 14 provided on the upper and lower surfaces of the vibration part 110. The piezoelectric vibration element 10 includes, for example, a type of piezoelectric substrate made of a piezoelectric material in which the vibration part 110 vibrates in response to an applied voltage. The excitation electrodes 14 apply an alternating voltage to the piezoelectric substrate of the vibration part 110 to excite the vibration part 110.

[0017] 2 is a plan view of the piezoelectric vibrator 1 seen from the side of the upper substrate layer 20. The piezoelectric vibrator 1 may have, for example, a rectangular shape.

[0018] 2, when the piezoelectric vibrator 1 is viewed from above in a plan view, a protective film F1 is provided on the outer periphery of the upper substrate layer 20. Specifically, the protective film F1 is provided in an area overlapping with a resin bonding material X1 provided on the outer periphery of the upper substrate layer 20 and a resin bonding material X2 provided on the outer periphery of the lower substrate layer 30. Note that the protective film F1 is not shown in FIG.

[0019] The protective film F1 has a light-blocking property against irradiation light (e.g., ultraviolet light) of a predetermined wavelength that is irradiated onto the sealed piezoelectric vibrator 1 and is used to clean the excitation electrodes inside the piezoelectric vibrator 1. The protective film F1 has a function of protecting the resin bonding material X1 and the resin bonding material X2 from the irradiation light. Here, the protective film F1 is not limited to a film that completely blocks the irradiation light, but also includes a film that mitigates the effects of the irradiation light. By blocking the irradiation light with the protective film F1, it is possible to prevent the irradiation light from hitting organic matter inside the piezoelectric vibrator 1 or to mitigate the effects of irradiation with the irradiation light.

[0020] FIG. 3 is a cross-sectional view taken along line III-III in FIG.

[0021] 3, the piezoelectric vibration element 10 has an excitation electrode 14a provided on the upper surface of the vibration part 110 and an excitation electrode 14b provided on the lower surface of the vibration part 110. The excitation electrode 14a and the excitation electrode 14b face each other in the thickness direction of the vibration part 110.

[0022] The excitation electrodes 14a and 14b apply an alternating voltage to the piezoelectric substrate of the vibration part 110 to excite the vibration part 110. The excitation electrodes 14a and 14b are provided, for example, in the center of the vibration part 110, and when viewed from above, the excitation electrodes 14a and 14b have a substantially rectangular shape similar to the vibration part 110, and may be arranged so that they substantially entirely overlap each other.

[0023] The shapes of the excitation electrodes 14a and 14b in plan view are not limited to rectangular. That is, they may be polygonal, circular, elliptical, or a combination of these. Furthermore, the shapes of the excitation electrodes 14a and 14b are not limited to being the same, and they may be different from each other. Furthermore, the areas of the two electrodes may be different.

[0024] The excitation electrodes 14a and 14b may have a single-layer structure made of, for example, an aluminum layer, but are not limited to this. The excitation electrodes 14a and 14b may also have a multilayer structure in which a base layer and a surface layer are stacked. For example, the base layer is a chromium (Cr) layer that has good adhesion to the quartz substrate, and the surface layer is a gold (Au) layer that has good chemical stability. The electrodes of the quartz vibrating element may contain silver (Ag), copper (Cu), titanium (Ti), molybdenum (Mo), or an aluminum-copper alloy (AlCu).

[0025] The piezoelectric vibration element 10 may also have a frame-shaped holding portion 120 that surrounds the vibration portion 110 at a distance from the vibration portion 110, and a support arm portion 130 that is connected to a part of the holding portion 120 and supports the vibration portion 110.

[0026] The vibrating section 110 is excited at a predetermined frequency based on the applied alternating voltage. The vibrating section 110 is held so as to be vibrable in a vibration space provided between the upper substrate layer 20 and the lower substrate layer 30. The main vibration of the vibrating section 110 is, for example, a thickness shear vibration mode.

[0027] The upper substrate layer 20 is provided on the upper surface side of the piezoelectric vibration element 10. That is, the upper substrate layer 20 faces the vibration portion 110, the holding portion 120, and the support arm portion 130 of the piezoelectric vibration element 10 with a gap interposed therebetween via the resin bonding material X1. The upper substrate layer 20 may be provided in a flat plate shape.

[0028] The lower substrate layer 30 is provided on the lower surface side of the piezoelectric vibration element 10, opposite the upper substrate layer 20. That is, the lower substrate layer 30 faces the vibration section 110, the holding section 120, and the support arm section 130 of the piezoelectric vibration element 10, with a gap interposed between them and the resin bonding material X2, on the opposite side of the upper substrate layer 20. The lower substrate layer 30 may be provided in a flat plate shape.

[0029] 1 , the resin bonding material X1 is provided along the outer periphery of the upper substrate layer 20. Here, the resin bonding material X1 may be provided in contact with the outer periphery edge of the upper substrate layer 20, or may be provided with a gap from the outer periphery edge. The resin bonding material X1 bonds the piezoelectric vibration element 10 and the outer periphery of the upper substrate layer 20 along the frame-like shape of the holding portion 120.

[0030] 1, the resin bonding material X2 is provided along the outer periphery of the lower substrate layer 30. Here, the resin bonding material X2 may be provided in contact with the outer periphery edge of the lower substrate layer 30, or may be provided with a gap from the outer periphery edge. The resin bonding material X2 bonds the piezoelectric vibration element 10 and the outer periphery of the lower substrate layer 30 along the frame-like shape of the holding portion 120.

[0031] The resin bonding material X1 and the resin bonding material X2 may be, for example, an organic adhesive containing an epoxy-based, vinyl-based, acrylic-based, urethane-based, or silicone-based resin.

[0032] The holding portion 120 is a portion for holding the vibration portion 110. The shape of the holding portion 120 is not limited to a frame shape. The holding portion 120 only needs to be provided in at least a part of the frame-shaped region surrounding the vibration portion 110, and may be provided in the shape of two rails, for example.

[0033] The support arm 130 is connected to a part of the holding part 120 to support the vibration part 110. The support arm 130 connects the vibration part 110 and the holding part 120. As shown in FIG. 3 , the support arm 130 connects a part of the vibration part 110 and a part of the holding part 120.

[0034] Here, the piezoelectric vibrator 1 may be, for example, a quartz crystal vibrator made of quartz crystal. In this case, the piezoelectric vibrator 1 may be used as a component of, for example, a temperature compensated crystal oscillator (TCXO), a voltage controlled crystal oscillator (VCXO), or an oven controlled crystal oscillator (OCXO).

[0035] The piezoelectric vibration element 10 may be a quartz vibration element. Specifically, the vibration part 110, the holding part 120, and the support arm part 130 may all be made of quartz. The vibration part 110 (piezoelectric substrate) may be, for example, an AT-cut quartz crystal substrate. Other cuts such as BT-cut, GT-cut, or SC-cut may also be used. Furthermore, the upper substrate layer 20 and the lower substrate layer 30 may be made of quartz crystal.

[0036] When the piezoelectric vibrating element 10, the upper substrate layer 20, and the lower substrate layer 30 are made of quartz crystal, the package of the piezoelectric vibrator 1 is translucent, which allows light (e.g., ultraviolet light) directed at the piezoelectric vibrator 1 to be irradiated to the inside of the piezoelectric vibrator 1, thereby cleaning the excitation electrodes 14 a and 14 b.

[0037] Cleaning the excitation electrodes 14a, 14b with irradiated light refers to, for example, irradiating the excitation electrodes 14a, 14b with ultraviolet light to remove or prevent foreign matter such as organic matter adhering to the surfaces of the excitation electrodes 14a, 14b. This makes it possible, for example, to adjust the frequency of the piezoelectric vibrator so that it is stable. Note that cleaning the excitation electrodes 14a, 14b with irradiated light may also include adjusting the frequency of the piezoelectric vibrator 1.

[0038] The irradiated light may be irradiated from the upper substrate layer 20 side or from the lower substrate layer 30 side.

[0039] The irradiation light may include, for example, ultraviolet light with a wavelength range of 100 to 600 nm (nanometers) or green laser. If the wavelength range is infrared light (760 to 830 nm), the absorption rate of the irradiation light may be low depending on the material of the excitation electrodes 14a, 14b, which may result in inefficient removal of organic matter from the surface. Therefore, a wavelength range of 100 to 600 nm is preferable.

[0040] 3, when ultraviolet light R is irradiated from the side of the upper substrate layer 20, the excitation electrode 14a is cleaned. Here, in the piezoelectric vibrator 1, the protective film F1 is provided on the upper substrate layer 20, so that the ultraviolet light R can be blocked from the resin bonding material X1 and the resin bonding material X2.

[0041] 2, the protective film F1 may be provided, for example, along the outer periphery of the upper substrate layer 20. That is, the protective film F1 is provided in an area overlapping with the resin bonding material X1 and the resin bonding material X2 in a plan view, thereby blocking ultraviolet rays R. This makes it possible to reduce the risk of frequency instability, such as when the ultraviolet rays R that clean the excitation electrode also hit the resin bonding material and the sealing property of the piezoelectric vibrator is impaired by outgassing caused by decomposition of organic matter.

[0042] The protective film F1 is made of a metal material, and may be at least one of titanium tungsten (TiW), copper (Cu), nickel (Ni), and gold (Au). Alternatively, the protective film F1 may have a structure in which a plurality of metal materials are stacked. This allows the protective film F1 to block irradiated light such as ultraviolet light R. By stacking these metal materials, the protective film F1 can be made thicker, further enhancing the light-blocking effect.

[0043] When irradiation light (e.g., ultraviolet light R) is irradiated from above, the protective film F1 may be provided on the upper substrate layer 20 in an area that overlaps with the resin bonding material X1 and the resin bonding material X2 in a planar view, on at least one of the outside and inside of the piezoelectric vibrator 1.

[0044] 3, the protective film F1 may be provided on the outside of the piezoelectric vibrator 1. That is, the protective film F1 may be provided on the outer periphery of the upper substrate layer 20, on the side of the piezoelectric vibrator 1 facing the outside.

[0045] 4, the protective film F1 may be provided on the inner side of the piezoelectric vibrator 1. That is, the protective film F1 may be provided on the outer periphery of the upper substrate layer 20 on the side facing the inside of the piezoelectric vibrator 1.

[0046] Also, although not shown, when the irradiation light is irradiated from below, the position of the protective film F1 may be provided on the lower substrate layer 30, on at least one of the outside and inside of the piezoelectric vibrator 1, in an area that overlaps with the resin bonding material X1 and the resin bonding material X2 in a planar view.

[0047] When the protective film F1 is provided on the outside of the lower substrate layer 30, it can also serve as the external electrode T.

[0048] In the piezoelectric vibrator 1 according to the first embodiment, by providing a protective film F1 at a predetermined position as needed, it is possible to prevent the resin bonding material inside the piezoelectric vibrator from being irradiated with irradiated light. In this way, the excitation electrodes of the piezoelectric vibrator 1 can be cleaned even after sealing, and the frequency of the vibration part can be adjusted. The position and number of the protective film F1 may be changed as appropriate according to the direction of the irradiated light and the position of the resin bonding material inside the piezoelectric vibrator.

[0049] 5 to 8, a piezoelectric vibrator 2 according to a second embodiment will be described. Differences from the first embodiment will be described below, and the details described in the first embodiment can be applied to the rest.

[0050] 5 is an exploded perspective view of the piezoelectric vibrator 2 according to the second embodiment. The piezoelectric vibrator 2 includes a piezoelectric vibrating element 40, an upper substrate layer 50, and a lower substrate layer 60.

[0051] The piezoelectric vibrator 2 has, for example, an outer edge of the upper substrate layer 50 extending out and bonded to the outer periphery of the lower substrate layer 60 by a resin bonding material X3, forming a sealed package structure inside which a vibration space is formed in which the vibration part of the piezoelectric vibration element 40 vibrates. The piezoelectric vibration element 40 is fixed to the lower substrate layer 60 by a conductive resin bonding material Y.

[0052] 6 is a plan view of the piezoelectric vibrator 2 seen from the side of the upper substrate layer 50. The piezoelectric vibrator 2 may have, for example, a rectangular shape.

[0053] 6, when the piezoelectric vibrator 2 is viewed from above in a plan view, a protective film F1 may be provided on the outer periphery of the upper substrate layer 50. In addition to the protective film F1, a protective film F2 is provided in a predetermined region of the short side of the upper substrate layer 50. Specifically, the protective film F1 is provided in a region overlapping with the resin bonding material X3 provided on the outer periphery of the lower substrate layer 60, and the protective film F2 is provided in a region overlapping with the conductive resin bonding material Y that fixes the piezoelectric vibrating element 40. Note that the protective films F1 and F2 are not shown in FIG.

[0054] FIG. 7 is a cross-sectional view taken along line VII-VII in FIG.

[0055] 7, the piezoelectric vibrator 2 has a cavity recess in at least one of the upper substrate layer 50 and the lower substrate layer 60. In the case of Fig. 7, the upper substrate layer 50 has the cavity recess, and the piezoelectric vibrating element 40 is housed in the cavity recess.

[0056] The piezoelectric vibration element 40 is fixed to the lower substrate layer 60 by a conductive resin bonding material Y.

[0057] The conductive resin bonding material Y is not limited to silicone resin as long as it is a curable resin, and may be, for example, epoxy resin or acrylic resin. The conductivity is not limited to being imparted by silver particles, and may be imparted by other metals, conductive ceramics, conductive organic materials, etc. Furthermore, the main component may be a conductive polymer.

[0058] Because the conductive resin bonding material Y is provided, as shown in Figure 6, the piezoelectric vibrator 2 has, in addition to the protective film F1, a protective film F2 in the area that overlaps with the conductive resin bonding material Y in a planar view of the upper substrate layer 50 and the lower substrate layer 60.

[0059] In the case of FIG. 7, a protective film F2 is provided on the upper substrate layer 50.

[0060] When irradiation light (e.g., ultraviolet light R) is irradiated from above, the protective film F1 and the protective film F2 may be provided on the upper substrate layer 50 in an area that overlaps with the resin bonding material X3 and the conductive resin bonding material Y in a planar view, on at least one of the outside and inside of the piezoelectric vibrator 2.

[0061] 7, the protective film F1 and the protective film F2 may be provided on the outside of the piezoelectric vibrator 2. That is, the protective film F1 may be provided on the outer periphery of the upper substrate layer 50, on the side facing outward of the piezoelectric vibrator 2. The protective film F2 may be provided at a predetermined position on the upper substrate layer 50, on the side facing outward of the piezoelectric vibrator 2.

[0062] 8, the protective film F1 and the protective film F2 may be provided on the inside of the piezoelectric vibrator 2. That is, the protective film F1 may be provided between the resin bonding material X3 that bonds the upper substrate layer 50 and the lower substrate layer 60 and the extended outer edge of the upper substrate layer 50. The protective film F2 may be provided at a predetermined position on the upper substrate layer 50 on the side facing inward of the piezoelectric vibrator 2.

[0063] Also, although not shown, when the irradiation light is irradiated from below, the positions of the protective film F1 and the protective film F2 may be provided on the lower substrate layer 60, on at least one of the outside and inside of the piezoelectric vibrator 2, in an area that overlaps with the resin bonding material X3 and the conductive resin bonding material Y in a planar view.

[0064] In addition, when the protective film F1 and the protective film F2 are provided on the outside of the lower substrate layer 60, they can also serve as the external electrodes T.

[0065] <Supplementary Notes> Some or all of the embodiments of the present invention are described below, but the present invention is not limited to the following supplementary notes.

[0066] <Supplementary Note 1> A piezoelectric vibrator comprising: a vibrating section; and a piezoelectric vibrating element having excitation electrodes provided on the upper and lower surfaces of the vibrating section, respectively; an upper substrate layer provided on the upper surface side of the piezoelectric vibrating element; a lower substrate layer provided on the lower surface side of the piezoelectric vibrating element; a first resin bonding material provided between the upper substrate layer and the lower substrate layer along the outer periphery in a planar view; and a first protective film provided on at least one of the upper substrate layer and the lower substrate layer in an area overlapping with the first resin bonding material in a planar view, the first protective film having light blocking properties against irradiation light of a predetermined wavelength that cleans the excitation electrodes.

[0067] According to Supplementary Note 1, when the excitation electrode is cleaned by irradiating it with light from outside the sealed piezoelectric vibrator, the protective film prevents the light from hitting the resin bonding material provided along the outer periphery in a planar view between the upper substrate layer and the lower substrate layer, and prevents the light from hitting the organic matter inside the piezoelectric vibrator, causing the organic matter to decompose, thereby preventing deterioration of sealing due to increased outgassing and frequency fluctuations.

[0068] <Supplementary Note 2> A piezoelectric vibrator according to Supplementary Note 1, wherein the piezoelectric vibration element further has a frame-shaped holding portion that surrounds the vibration portion at a distance from the vibration portion, and a support arm portion that connects to a part of the holding portion and supports the vibration portion, and the piezoelectric vibrator further comprises: a first bonding portion at which the upper substrate layer and the holding portion of the piezoelectric vibration element are bonded on their upper surface side by a first resin bonding material; and a second bonding portion at which the lower substrate layer and the holding portion of the piezoelectric vibrator are bonded on their lower surface side by the first resin bonding material.

[0069] According to Supplementary Note 2, the present invention can be applied to a piezoelectric vibrator having a structure in which a piezoelectric vibrating element is sandwiched between an upper substrate layer and a lower substrate layer (for example, a WLP (Wafer Level Packaging) structure).

[0070] <Supplementary Note 3> A piezoelectric vibrator according to Supplementary Note 1, wherein at least one of the upper substrate layer and the lower substrate layer has a cavity recess, the piezoelectric vibrating element is housed in the cavity recess, and the piezoelectric vibrator further comprises: a second resin bonding material that fixes the piezoelectric vibrating element to the lower substrate layer; and a second protective film that is provided in at least one of the upper substrate layer and the lower substrate layer in an area that overlaps with the second resin bonding material in a planar view of the upper substrate layer and the lower substrate layer and that has light-blocking properties against irradiation light of a predetermined wavelength that cleans the excitation electrode.

[0071] According to Supplementary Note 3, the present invention can be applied to a piezoelectric vibrator in a package in which, for example, an upper substrate layer of a cap structure is joined to a lower substrate layer.

[0072] <Supplementary Note 4> The piezoelectric vibrator according to Supplementary Note 2, wherein the first protective film is provided on the upper substrate layer in an area that overlaps with the first resin bonding material in a plan view on at least one of the outer side and the inner side of the piezoelectric vibrator.

[0073] According to Appendix 4, for example, in a piezoelectric vibrator having a WLP structure, when light is irradiated onto an excitation electrode inside the piezoelectric vibrator from the side of the upper substrate layer, a protective film provided on at least one of the outside and inside of the upper substrate layer can prevent the light from hitting the resin bonding material inside the piezoelectric vibrator.

[0074] <Supplementary Note 5> The piezoelectric vibrator according to Supplementary Note 3, wherein the second protective film is provided on the upper substrate layer in an area that overlaps with the second resin bonding material in a planar view on at least one of the outside and the inside of the piezoelectric vibrator.

[0075] According to Appendix 5, in a piezoelectric vibrator having a package structure in which an upper substrate layer (or lower substrate layer) of a cap structure is joined to the other lower substrate layer (or upper substrate layer), for example, when irradiating light from the upper substrate layer side onto an excitation electrode inside the piezoelectric vibrator, a protective film provided on at least one of the outside and inside of the upper substrate layer can prevent the irradiated light from hitting the resin bonding material (including conductive resin bonding material) inside the piezoelectric vibrator.

[0076] <Supplementary Note 6> The piezoelectric vibrator according to Supplementary Note 1 or Supplementary Note 2, wherein the first protective film is provided on the lower substrate layer in an area that overlaps with the first resin bonding material in a planar view on at least one of the outside and the inside of the piezoelectric vibrator.

[0077] According to Appendix 6, for example, in a piezoelectric vibrator having a WLP structure, when irradiating light onto an excitation electrode inside the piezoelectric vibrator from the side of the lower substrate layer, a protective film provided on at least one of the outside and inside of the lower substrate layer can prevent the irradiated light from hitting the resin bonding material inside the piezoelectric vibrator.

[0078] <Supplementary Note 7> The piezoelectric vibrator according to Supplementary Note 1 or Supplementary Note 3, wherein the second protective film is provided on the lower substrate layer in an area that overlaps with the second resin bonding material in a planar view on at least one of the outside and the inside of the piezoelectric vibrator.

[0079] According to Appendix 7, in a piezoelectric vibrator having a package structure in which an upper substrate layer (or lower substrate layer) of an example cap structure is joined to the other lower substrate layer (or upper substrate layer), for example, when irradiating light onto an excitation electrode inside the piezoelectric vibrator from the side of the lower substrate layer, a protective film provided on at least one of the outside and inside of the lower substrate layer can prevent the irradiated light from hitting the resin bonding material (including conductive resin bonding material) inside the piezoelectric vibrator.

[0080] <Supplementary Note 8> The piezoelectric vibrator according to any one of Supplementary Note 1, Supplementary Note 4, and Supplementary Note 6, wherein the first protective film is made of a metal material, and the metal material includes at least one of titanium tungsten, copper, nickel, and gold.

[0081] According to Supplementary Note 8, the protective film provided is made of a predetermined metal material, which makes it difficult for the irradiated light to pass through, thereby providing the effect of further preventing the irradiated light from reaching the resin bonding material.

[0082] <Supplementary Note 9> The piezoelectric vibrator according to any one of Supplementary Note 1 to Supplementary Note 8, wherein the piezoelectric vibrating element is a quartz vibrating element, and the upper substrate layer and the lower substrate layer are made of quartz.

[0083] According to Supplementary Note 9, the present invention can be applied when the piezoelectric vibrator is a quartz vibrator.

[0084] REFERENCE SIGNS LIST 1... Piezoelectric vibrator 10... Piezoelectric vibrating element 14... Excitation electrode 14a... Excitation electrode 14b... Excitation electrode 110... Vibration section 120... Holding section 130... Support arm section 20... Upper substrate layer X1... Resin bonding material 30... Lower substrate layer X2... Resin bonding material T... External electrode R... Irradiated light (ultraviolet light) F1... Protective film 2... Piezoelectric vibrator 40... Piezoelectric vibrating element 50... Upper substrate layer 60... Lower substrate layer X3... Resin bonding material Y... Conductive resin bonding material F2... Protective film

Claims

1. A piezoelectric vibrator comprising: a vibrating section; and a piezoelectric vibrating element having excitation electrodes provided on the upper and lower surfaces of the vibrating section; an upper substrate layer provided on the upper surface side of the piezoelectric vibrating element; a lower substrate layer provided on the lower surface side of the piezoelectric vibrating element; a first resin bonding material provided between the upper substrate layer and the lower substrate layer along the outer periphery in a planar view; and a first protective film provided on at least one of the upper substrate layer and the lower substrate layer in an area overlapping with the first resin bonding material in a planar view, the first protective film having light blocking properties against irradiation light of a predetermined wavelength that cleans the excitation electrodes.

2. The piezoelectric vibrator according to claim 1, wherein the piezoelectric vibrating element further has a frame-shaped holding portion that is spaced apart from the vibrating portion and surrounds the vibrating portion, and a support arm portion that is connected to a part of the holding portion and supports the vibrating portion, and the piezoelectric vibrator further comprises: a first bonding portion where the upper substrate layer and the holding portion of the piezoelectric vibrating element are bonded on the upper surface side with the first resin bonding material; and a second bonding portion where the lower substrate layer and the holding portion of the piezoelectric vibrator are bonded on the lower surface side with the first resin bonding material.

3. A piezoelectric vibrator as described in claim 1, wherein at least one of the upper substrate layer and the lower substrate layer has a cavity recess, the piezoelectric vibrating element is housed in the cavity recess, and the piezoelectric vibrator further comprises: a second resin bonding material that fixes the piezoelectric vibrating element to the lower substrate layer; and a second protective film that is provided on at least one of the upper substrate layer and the lower substrate layer in an area that overlaps with the second resin bonding material in a planar view of the upper substrate layer and the lower substrate layer and that has light blocking properties against irradiation light of a predetermined wavelength that cleans the excitation electrode.

4. A piezoelectric vibrator as described in claim 2, wherein the first protective film is provided on the upper substrate layer in an area that overlaps with the first resin bonding material in a planar view on at least one of the outside and inside of the piezoelectric vibrator.

5. A piezoelectric vibrator as described in claim 3, wherein the second protective film is provided on the upper substrate layer in an area that overlaps with the second resin bonding material in a planar view on at least one of the outside and inside of the piezoelectric vibrator.

6. A piezoelectric vibrator according to claim 1 or claim 2, wherein the first protective film is provided on the lower substrate layer in an area that overlaps with the first resin bonding material in a plan view, on at least one of the outside and inside of the piezoelectric vibrator.

7. A piezoelectric vibrator as described in claim 1 or claim 3, wherein the second protective film is provided on the lower substrate layer in an area that overlaps with the second resin bonding material in a plan view, on at least one of the outside and inside of the piezoelectric vibrator.

8. The piezoelectric vibrator according to any one of claims 1, 4 and 6, wherein the first protective film is made of a metal material, and the metal material includes at least one of titanium tungsten, copper, nickel and gold.

9. A piezoelectric vibrator according to any one of claims 1 to 8, wherein the piezoelectric vibrating element is a quartz vibrating element, and the upper substrate layer and the lower substrate layer are made of quartz.

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