CN118140416A

CN118140416A - Piezoelectric vibration device with thermistor

Info

Publication number: CN118140416A
Application number: CN202280069888.7A
Authority: CN
Inventors: 森本贤周
Original assignee: Large Vacuum Of Co
Current assignee: Large Vacuum Of Co
Priority date: 2021-11-01
Filing date: 2022-10-24
Publication date: 2024-06-04

Abstract

A piezoelectric vibration device (1) with a thermistor is provided with a sandwich device (2) and a sheet-type thermistor (5) mounted on the outer surface of a first sealing member (20) in the sandwich device (2). The sheet thermistor (5) is arranged so as to overlap at least a part of the vibrating portion (13) of the sandwich element (2) in a plan view. The piezoelectric vibrating plate (10) in the sandwich device (2) has a vibrating portion (13), an outer frame (14) surrounding the outer periphery of the vibrating portion (13), and a holding portion (15) for holding the vibrating portion (13) by connecting the vibrating portion (13) to the outer frame (14). The sheet thermistor (5) is arranged so as to overlap with outer frame parts (14) on two sides of the sandwich device (2) that face each other.

Description

Piezoelectric vibration device with thermistor

Technical Field

The invention relates to a piezoelectric vibration device with a thermistor, wherein the piezoelectric vibration device with the sandwich structure is provided with the thermistor.

Background

In recent years, the frequency of operation of various electronic devices has been increased, and the size of packages (particularly, the height thereof) has been reduced. Accordingly, along with the increase in frequency and the miniaturization of packages, piezoelectric vibration devices (e.g., crystal resonators, crystal oscillators, etc.) are demanded to also correspond to the increase in frequency and the miniaturization of packages.

The case of such a piezoelectric vibration device is constituted by an approximately rectangular parallelepiped package. The package includes a first sealing member and a second sealing member made of glass or crystal, for example, and a piezoelectric vibrating plate made of crystal, for example, and having excitation electrodes formed on both principal surfaces, the first sealing member and the second sealing member being laminated and bonded with the piezoelectric vibrating plate interposed therebetween. The vibrating portion (excitation electrode) of the piezoelectric vibrating plate disposed inside the package (internal space) is hermetically sealed. Hereinafter, the laminated form of such piezoelectric vibration devices is referred to as a sandwich structure, and the piezoelectric vibration devices of the sandwich structure are referred to as sandwich devices.

As a piezoelectric vibration device, a thermistor-attached piezoelectric vibration device having a thermistor mounted thereon is also widely used (for example, patent document 1 and patent document 2). However, no product has been found to be formed by mounting a thermistor to a sandwich device to form a piezoelectric vibration device with a thermistor. Moreover, there is a significant technical problem with the sandwich device. In the case of a sandwich device which is a piezoelectric vibration device with a thermistor, there is also a need to solve the technical problems existing in the sandwich device.

For example, since the sandwich device is a thin device realizing low-profile, the internal excitation electrode is susceptible to external noise, and thus noise countermeasure is important. In the case where the sandwich device is a piezoelectric vibration device with a thermistor, such a technical problem needs to be solved as well.

In addition, since the sandwich device is a thin device realizing low-profile, there is a technical problem of low strength. In the case where the sandwich device is a piezoelectric vibration device with a thermistor, such a technical problem needs to be solved as well.

[ Patent document 1] the following: japanese patent No. 5900582

[ Patent document 2 ] the following: japanese patent No. 5888347

Disclosure of Invention

In view of the above, an object of the present invention is to solve the technical problems existing in the sandwich device by using the mounted thermistor in the case where the sandwich device is a piezoelectric vibration device with a thermistor. Specifically, a first object of the present invention is to: provided is a piezoelectric vibration device with a thermistor which uses a sandwich device and takes excellent noise countermeasures; a second object of the present invention is to: provided is a piezoelectric vibration device with a thermistor, wherein a sandwich device is used and a countermeasure in terms of strength is taken.

In order to solve the above-described problems, a piezoelectric vibration device with a thermistor according to a first aspect of the present invention is characterized in that: a piezoelectric vibration device having a sandwich structure, wherein a first sealing member is laminated and joined to a piezoelectric vibrating plate having a vibration portion in which a first excitation electrode is formed on a first main surface and a second excitation electrode is formed on a second main surface, and a second sealing member is laminated and joined to the piezoelectric vibrating plate so as to cover the first main surface side of the piezoelectric vibrating plate, thereby forming an internal space in which the vibration portion is hermetically sealed; the sheet thermistor is mounted on an outer surface of the first sealing member in the piezoelectric vibration device; the sheet-type thermistor is configured to overlap at least a part of the vibration portion in a plan view.

Based on the above-described structure, the sheet thermistor can be used to shield the vibrating portion by disposing the sheet thermistor so as to overlap the vibrating portion of the piezoelectric vibrating device.

In the piezoelectric vibration device with a thermistor, the sheet-type thermistor may be arranged so as to overlap the entirety of the first excitation electrode and the second excitation electrode in a plan view.

With the above configuration, the shielding effect of the sheet thermistor can be maximally exhibited by overlapping the sheet thermistor with the entire first excitation electrode and the second excitation electrode.

In the above-described piezoelectric vibration device with a thermistor, the sheet-type thermistor may be configured such that a common electrode is formed on one main surface of the single-piece thermistor sheet, and a divided electrode is formed on the other main surface, and the common electrode is formed on substantially the entire surface of the thermistor sheet.

With the above configuration, the shielding performance of the sheet thermistor can be improved by enlarging the area of the common electrode on the sheet thermistor.

In the above-described piezoelectric vibration device with a thermistor, the sheet-type thermistor may be configured such that a common electrode is formed on one main surface of the single-piece thermistor sheet, and a divided electrode is formed on the other main surface, and the divided electrode is formed in a portion that occupies half or more of the area of the thermistor sheet.

With the above configuration, the area of the divided electrode on the sheet thermistor is enlarged, so that the sheet thermistor can exhibit a good shielding performance.

In order to solve the above-described problems, a piezoelectric vibration device with a thermistor according to a second aspect of the present invention is characterized in that: a piezoelectric vibration device having a sandwich structure, wherein a first sealing member is laminated and joined to a piezoelectric vibrating plate having a vibration portion in which a first excitation electrode is formed on a first main surface and a second excitation electrode is formed on a second main surface, and a second sealing member is laminated and joined to the piezoelectric vibrating plate so as to cover the first main surface side of the piezoelectric vibrating plate, thereby forming an internal space in which the vibration portion is hermetically sealed; the sheet thermistor is mounted on an outer surface of the first sealing member in the piezoelectric vibration device; the piezoelectric vibrating plate includes the vibrating portion, an outer frame portion surrounding an outer periphery of the vibrating portion, and a holding portion that holds the vibrating portion by connecting the vibrating portion to the outer frame portion; the sheet-type thermistor is arranged to overlap the outer frame portions on both sides of the piezoelectric vibration device facing each other.

With the above configuration, the strength of the piezoelectric vibration device with the thermistor can be ensured by bonding the sheet-like thermistor to the outer peripheral portion of the piezoelectric vibration device, that is, by disposing the sheet-like thermistor so as to overlap the outer frame portion.

In the piezoelectric vibration device with a thermistor, the sheet-type thermistor and the piezoelectric vibration device may be electrically connected to each other by a conductive resin adhesive, and a gap between the sheet-type thermistor and the piezoelectric vibration device may be filled with a nonconductive resin adhesive.

With the above configuration, the sheet thermistor is surface-bonded to the piezoelectric vibration device by the conductive resin adhesive and the nonconductive resin adhesive, and the thermal conductivity between the sheet thermistor and the piezoelectric vibration device can be improved. This makes it possible to maintain the temperature of the sheet thermistor close to the temperature of the vibration portion of the piezoelectric vibration device. In addition, by bonding the piezoelectric vibration device to the sheet-type thermistor surface, the strength of the piezoelectric vibration device with a thermistor can be improved.

In the above-described piezoelectric vibration device with a thermistor, the conductive resin adhesive may have a higher thermal conductivity than the non-conductive resin adhesive.

With the above configuration, the thermal conductivity between the sheet thermistor and the piezoelectric vibration device can be further improved.

In the above-described piezoelectric vibration device with a thermistor, the non-conductive resin adhesive may have a hardness higher than that of the conductive resin adhesive.

With the above structure, the stress between the sheet thermistor and the piezoelectric vibration device can be relieved, and the package strength of the piezoelectric vibration device with the thermistor can be improved.

In the above-described piezoelectric vibration device with a thermistor, the first sealing member and the second sealing member may be made of brittle materials.

The invention has the following effects:

The piezoelectric vibration device with a thermistor according to the first aspect of the present invention can obtain the following effects. That is, by disposing the sheet-type thermistor having the electrode with a large area so as to overlap the vibration portion, the sheet-type thermistor can be used for shielding of the vibration portion, and thus a piezoelectric vibration device with a thermistor that takes excellent countermeasures against noise while using a sandwich device can be realized.

In addition, the piezoelectric vibration device with a thermistor according to the second aspect of the present invention can obtain the following effects. That is, by joining the sheet-type thermistor to the outer peripheral portion of the sandwich element, that is, disposing the sheet-type thermistor so as to overlap the outer frame portion, it is possible to realize a piezoelectric vibration element with a thermistor in which measures in terms of strength are taken while using the sandwich element.

Drawings

Fig. 1 is a plan view showing a piezoelectric vibration device with a thermistor according to a first embodiment of the present invention.

Fig. 2 is a cross-sectional view of the piezoelectric vibration device with a thermistor of fig. 1.

Fig. 3 is a plan view showing the first main surface of the piezoelectric vibrating plate in the sandwich device.

Fig. 4 is a plan view showing the second main surface of the piezoelectric vibrating plate in the sandwich device.

FIG. 5 is a top view showing the first major face of the first sealing member in the sandwich device.

FIG. 6 is a top view showing the second major face of the first sealing member in a sandwich device.

FIG. 7 is a top view showing the first major face of the second sealing member in a sandwich device.

FIG. 8 is a top view showing the second major face of the second sealing member in the sandwich device.

Fig. 9 (a) is a top view of the sheet type thermistor.

Fig. 9 (b) is a bottom view of the sheet type thermistor.

Fig. 10 is an exploded perspective view showing the components of a crystal oscillator with a thermistor according to a second embodiment of the present invention.

Fig. 11 is a plan view of one principal surface of the piezoelectric vibrating plate.

Fig. 12 is a plan view of the other main surface (bottom surface) of the second seal member.

FIG. 13 is a cross-sectional view taken along line A-A of the assembly of the various components of FIG. 10.

Fig. 14 is a plan view of one principal surface of the plate-like thermistor.

Fig. 15 is a plan view of the other main surface of the plate-like thermistor.

Fig. 16 is a cross-sectional view showing another example of the plate-like thermistor.

Detailed Description

< First embodiment >, first embodiment

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Fig. 1 is a plan view of a piezoelectric vibration device with a thermistor (hereinafter referred to as the device) 1 according to the present embodiment. Fig. 2 is a cross-sectional view of the present device 1 (cross-sectional view taken along line A-A in fig. 1). As shown in fig. 1 and 2, the present device 1 is a device in which a sheet thermistor 5 is mounted on a sandwich device (a piezoelectric vibration device having a sandwich structure) 2.

First, the structure of the sandwich device 2 will be explained. As shown in fig. 2, the sandwich device 2 includes a piezoelectric vibrating plate 10, a first sealing member 20, and a second sealing member 30. In the sandwich device 2, the first sealing member 20 is joined to the piezoelectric vibrating plate 10, and the piezoelectric vibrating plate 10 is joined to the second sealing member 30, whereby a package having a sandwich structure of approximately rectangular parallelepiped shape is formed.

Fig. 3 is a plan view showing one principal surface (surface bonded to the first sealing member 20), i.e., the first principal surface 11, of the single piezoelectric vibrating plate 10 before bonding. Fig. 4 is a plan view showing the other main surface (surface to be joined to the second sealing member 30), that is, the second main surface 12 of the single piezoelectric vibrating plate 10 before joining. The piezoelectric vibrating plate 10 is a piezoelectric substrate made of a piezoelectric material such as crystal, and both principal surfaces (first principal surface 11 and second principal surface 12) thereof are processed (mirror-finished) to be flat and smooth surfaces. In the present embodiment, the piezoelectric vibrating plate 10 uses an AT wafer for thickness shear vibration.

In fig. 3 to 8, directions A1 and A2 indicate the longitudinal directions of the piezoelectric vibrating plate 10, the first sealing member 20, and the second sealing member 30, and directions B1 and B2 indicate the short-side directions of the piezoelectric vibrating plate 10, the first sealing member 20, and the second sealing member 30. In the piezoelectric vibrating plate 10, the two main surfaces of the piezoelectric vibrating plate 10 are XZ 'planes, and the direction parallel to the short side direction is the X-axis direction and the direction parallel to the long side direction is the Z' -axis direction.

The piezoelectric vibrating plate 10 has a vibrating portion 13 configured to be approximately rectangular, an outer frame portion 14 surrounding an outer periphery of the vibrating portion 13, and a holding portion 15 that holds the vibrating portion 13 by connecting the vibrating portion 13 and the outer frame portion 14. The portion between the vibrating portion 13 and the outer frame portion 14 is a cut-away portion (an opening portion through which the piezoelectric vibrating plate 10 passes in the thickness direction thereof) except for a portion where the holding portion 15 is formed. Thus, the piezoelectric vibrating plate 10 has a structure in which the vibrating portion 13, the outer frame portion 14, and the holding portion 15 are integrally formed. A pair of excitation electrodes (first excitation electrode 111, second excitation electrode 121) are formed on the first main surface 11 and the second main surface 12 of the piezoelectric vibrating plate 10.

In the present embodiment, the holding portion 15 is provided only at one portion between the vibrating portion 13 and the outer frame portion 14. The vibrating portion 13 and the holding portion 15 are thinner than the outer frame portion 14. By making the outer frame 14 and the holding portion 15 different in thickness, the natural frequency of the piezoelectric vibration of the outer frame 14 and the holding portion 15 can be made different, and resonance between the outer frame 14 and the piezoelectric vibration of the holding portion 15 is made less likely to occur. However, the formation site of the holding portion 15 is not limited to one site, and the holding portion 15 may be provided at two sites between the vibrating portion 13 and the outer frame portion 14.

The first excitation electrode 111 is provided on the first main surface 11 side of the vibration portion 13, and the second excitation electrode 121 is provided on the second main surface 12 side of the vibration portion 13. To the first excitation electrode 111 and the second excitation electrode 112, lead-out wirings (first lead-out wiring 112 and second lead-out wiring 122) for connecting these excitation electrodes to external electrode terminals are connected. The first lead-out wiring 112 is led out from the first excitation electrode 111, and is connected to a connection bonding pattern 114 formed on the outer frame 14 via the holding portion 15. The second lead-out wiring 122 is led out from the second excitation electrode 121, and is connected to the connection bonding pattern 124 formed on the outer frame 14 via the holding portion 15.

On the first main surface 11 and the second main surface 12 of the piezoelectric vibrating plate 10, a bonding pattern for bonding the piezoelectric vibrating plate 10 to the first sealing member 20 and the second sealing member 30 is formed. The bonding pattern includes a sealing pattern for hermetically sealing the internal space of the package, and a conductive pattern for conducting the wiring and the electrode. In fig. 3, 4, 6, and 7, the bonding region where the bonding pattern is formed is indicated by hatching.

As a sealing pattern on the piezoelectric vibrating plate 10, a vibration-side first bonding pattern 113 is formed on the first main surface 11, and a vibration-side second bonding pattern 123 is formed on the second main surface 12. The vibration-side first bonding pattern 113 and the vibration-side second bonding pattern 123 are provided in the outer frame portion 14, and are configured to be seen in a ring shape in a depression. The inner region of the vibration-side first bonding pattern 113 and the vibration-side second bonding pattern 123 is a sealing region of the vibration portion 13 (a region that becomes an internal space of the package after bonding). The first excitation electrode 111 and the second excitation electrode 121 are not electrically connected to the vibration-side first bonding pattern 113 and the vibration-side second bonding pattern 123.

As the conductive pattern in the piezoelectric vibrating plate 10, four connection bonding patterns 115 are formed outside the sealing region (outside the vibration-side first bonding pattern 113) of the first main surface 11, and connection bonding patterns 114, 116 are formed inside the sealing region (inside the vibration-side first bonding pattern 113). Four connection bonding patterns 125 are formed outside the sealing region (outside the vibration-side second bonding pattern 123) of the second main surface 12, and connection bonding patterns 124 are formed inside the sealing region (inside the vibration-side first bonding pattern 113). The connection bonding patterns 115 and 125 are provided in regions near four corners (corner portions) of the outer frame 14.

In the piezoelectric vibrating plate 10, a plurality of through holes 16 are formed between the first main surface 11 and the second main surface 12, and through electrodes for conducting between the first main surface 11 and the second main surface 12 are formed on the inner wall surfaces of the through holes 16. Specifically, there are formed: four through holes 16 (and through electrodes) for conducting between the connection bonding pattern 115 and the connection bonding pattern 125, and one through hole 16 (and through electrodes) for conducting between the connection bonding pattern 116 and the connection bonding pattern 124.

In the piezoelectric vibrating plate 10, the first excitation electrode 111, the second excitation electrode 121, the first lead-out wiring 112, the second lead-out wiring 122, the vibration side first bonding pattern 113, the vibration side second bonding pattern 123, the connection bonding patterns 114 to 116, the connection bonding pattern 124, and the connection bonding pattern 125 can be formed by the same process. Specifically, they may be formed of a base film (Ti film) formed by physical vapor deposition on both main surfaces of the piezoelectric vibrating plate 10, and a bonding film (Au film) formed by lamination of the base film by physical vapor deposition. The structure of the laminated film forming the bonding pattern is not limited to a two-layer structure of the Ti film and the Au film, and may be a structure of three or more layers including other films (for example, a separator formed between the Ti film and the Au film).

Fig. 5 is a plan view showing one main surface (outer surface) of the single first seal member 20 before joining, that is, the first main surface 21. Fig. 6 is a plan view showing the other main surface (surface to be bonded to the piezoelectric vibrating plate 10), that is, the second main surface 22 of the single first sealing member 20 before bonding. The first sealing member 20 is a rectangular parallelepiped substrate made of one glass wafer or one crystal wafer, and the second main surface 22 of the first sealing member 20 is processed (mirror-finished) to be a flat and smooth surface.

As shown in fig. 5, two electrode patterns 211, a wiring pattern 212, and a wiring pattern 213 are formed on the first main surface 21 of the first sealing member 20. The electrode pattern 211 is a mounting pad for mounting the sheet type thermistor 5 (refer to fig. 1). The wiring pattern 212 is a part of a wiring path connecting the first excitation electrode 111 to the external electrode terminal 321 (see fig. 8). The wiring pattern 213 becomes a part of a wiring path connecting the second excitation electrode 121 to the external electrode terminal 321.

As shown in fig. 6, a bonding pattern for bonding the first sealing member 20 to the piezoelectric vibrating plate 10 is formed on the second main surface 22 of the first sealing member 20. The bonding pattern includes a sealing pattern for hermetically sealing an inner space of the package; and a conductive pattern for conducting the wiring and the electrode.

As a pattern for sealing on the first sealing member 20, a sealing-side first bonding pattern 221 is formed. The sealing-side first bonding pattern 221 is configured to be seen as a ring shape in plan view, and an inner region thereof is a sealing region. As the conductive pattern on the first sealing member 20, four connection bonding patterns 222 are formed near four corners (corner portions) outside the sealing region (outside the sealing side first bonding pattern 221), and connection bonding patterns 223 to 225 are formed inside the sealing region (inside the sealing side first bonding pattern 221). The connection bonding pattern 224 and the connection bonding pattern 225 are connected by a wiring pattern 226.

In the first sealing member 20, a plurality of through holes 23 are formed between the first main surface 21 and the second main surface 22, and a through electrode for conducting between the first main surface 21 and the second main surface 22 is formed on an inner wall surface of each through hole 23. Specifically, there are formed: four through holes 23 (and through electrodes) for conducting between the electrode patterns 211 or the wiring patterns 212 and 213 and the connection bonding patterns 222; a through hole 23 (and a through electrode) for conducting between the wiring pattern 212 and the connection bonding pattern 223; and a through hole 23 (and a through electrode) for conducting between the wiring pattern 213 and the connection bonding pattern 225.

In the first sealing member 20, the sealing-side first bonding pattern 221, the connection bonding patterns 222 to 225, and the wiring pattern 226 can be formed by the same process. Specifically, they may be formed of a base film (Ti film) formed by physical vapor deposition on the second main surface 22 of the first sealing member 20, and a bonding film (Au film) formed by lamination of the base film by physical vapor deposition.

Fig. 7 is a plan view showing one principal surface (surface to be bonded to the piezoelectric vibrating plate 10), i.e., the first principal surface 31, of the single second sealing member 30 before bonding. Fig. 8 is a plan view showing the other main surface (outer surface) of the single second sealing member 30 before joining, that is, the second main surface 32. The second sealing member 30 is a rectangular parallelepiped substrate made of one glass wafer or one crystal wafer, and the first main surface 31 of the second sealing member 30 is processed (mirror-finished) to be a flat and smooth surface.

As shown in fig. 7, a bonding pattern for bonding the second sealing member 30 to the piezoelectric vibrating plate 10 is formed on the first main surface 31 of the second sealing member 30. The bonding pattern includes a sealing pattern for hermetically sealing an inner space of the package; and a conductive pattern for conducting the wiring and the electrode.

As a pattern for sealing on the second sealing member 30, a sealing-side second bonding pattern 311 is formed. The sealing-side second bonding pattern 311 is configured to be seen as a ring shape in plan view, and an inner region thereof is a sealing region. As the conductive pattern on the second sealing member 30, four connection bonding patterns 312 are formed near four corners (corner portions) outside the sealing region (outside the sealing side second bonding pattern 311).

As shown in fig. 8, four external electrode terminals 321 electrically connecting the device 1 to the outside are provided on the second main surface 32 of the second sealing member 30. The external electrode terminals 321 are located at four corners (corner portions) of the second sealing member 30, respectively.

In the second sealing member 30, a plurality of through holes 33 are formed between the first main surface 31 and the second main surface 32, and a through electrode for conducting between the first main surface 31 and the second main surface 32 is formed on an inner wall surface of each through hole 33. Specifically, four through holes 33 (and through electrodes) for conducting between the connection bonding pattern 312 and the external electrode terminal 321 are formed.

In the second sealing member 30, the sealing-side second bonding pattern 311 and the connection bonding pattern 312 may be formed by the same process. Specifically, they may be formed of a base film (Ti film) formed by physical vapor deposition on the first main surface 31 of the second sealing member 30, and a bonding film (Au film) formed by lamination of the base film by physical vapor deposition.

In the sandwich device 2, the piezoelectric vibrating plate 10 and the first sealing member 20 are diffusion bonded in a state where the vibrating plate side first bonding pattern 113 and the sealing side first bonding pattern 221, which are sealing patterns, overlap; the piezoelectric vibrating plate 10 and the second sealing member 30 are diffusion bonded in a state where the vibrating plate side second bonding pattern 123 and the sealing side second bonding pattern 311, which are sealing patterns, overlap, thereby manufacturing a package having a sandwich structure. That is, the vibration-side first bonding pattern 113 and the sealing-side first bonding pattern 221 are bonded to form a sealing pattern layer between the piezoelectric vibrating plate 10 and the first sealing member 20, and the vibration-side second bonding pattern 123 and the sealing-side second bonding pattern 311 are bonded to form a sealing pattern layer between the piezoelectric vibrating plate 10 and the second sealing member 30. Thereby, the internal space of the package, that is, the accommodation space of the vibration portion 13 is hermetically sealed.

At this time, the connection bonding patterns as the conductive patterns are also bonded to each other, and the conductive patterns bonded to each other become conductive pattern layers between the piezoelectric vibrating plate 10 and the first sealing member 20 or between the piezoelectric vibrating plate 10 and the second sealing member 30. In the sandwich device 2, electrical conduction is achieved between the first excitation electrode 111 and the second excitation electrode 121 and the external electrode terminals 321 (lower right and upper left in fig. 8). Also, electrical conduction is achieved between the sheet thermistor 5 mounted on the sandwich device 2 and the external electrode terminals 321 (upper right and lower left in fig. 8).

Fig. 9 (a) is a top view of the sheet thermistor 5; fig. 9 (b) is a bottom view of the sheet thermistor 5. The sheet thermistor 5 is an NTC thermistor thinned for good combination with the sandwich device 2, and has a common electrode 52 as a relay electrode formed on one main surface of the single thermistor sheet 51 and a divided electrode 53 as an operation electrode formed on the other main surface. In the present device 1, the thickness of the sandwich device 2 is about 120 μm, and the thickness of the sheet thermistor 5 may be less than half (about 50 μm) of the thickness of the sandwich device 2.

As the thermistor sheet 51, for example, a manganese-based semiconductor ceramic plate can be used. More specifically, the mn—fe—ni based material is formed into a paste together with an adhesive or the like, a thick film forming technique such as a screen printing technique or a doctor blade technique is used to form a green sheet from a wafer-state member of the thermistor sheet 51, and the green sheet is sintered and formed into a wafer of the thermistor sheet 51 by a firing technique. In addition, the Mn-Fe-Ni based material is not limited, and Mn-Co based material or Fe-Ni based material may be used.

The common electrode 52 is formed on the entire surface (or substantially the entire surface) of the thermistor sheet 51. The divided electrodes 53 are arranged at two positions at both ends along one direction (preferably the longitudinal direction) of the thermistor sheet 51, and occupy more than half of the area of the thermistor sheet 51. Each electrode is formed by forming an electrode film (metal film) on the thermistor sheet 51 by sputtering, and patterning the electrode film by a photolithography technique. As a specific metal material, a laminated structure of Ti film, niTi film, and Au film may be used, or another metal film structure may be used. In the case of using the laminated structure in which the Ti film, niTi film, and Au film are laminated, when finally solder-bonding the sheet thermistor 5 to the mounting substrate (in this case, the first sealing member 20), conductive bonding can be performed stably, and solder corrosion is less likely to occur.

In this way, the sheet-type thermistor 5 has a large-area metal electrode (the common electrode 52 and the divided electrode 53), and therefore can function well as a shielding member of the sandwich device 2. In order to use the sheet thermistor 5 as a shielding member, in the present device 1, the sheet thermistor 5 is arranged so as to overlap at least a part of the vibration portion 13 of the sandwich device 2 in a plan view (see fig. 1). Further, the sheet-type thermistor 5 is preferably arranged so as to overlap the entire first excitation electrode 111 and the second excitation electrode 121 in a plan view, so that the shielding effect of the sheet-type thermistor 5 can be maximally exhibited.

The sheet thermistor 5 is arranged such that both ends overlap the outer frame 14 at least on two sides of the sandwich element 2 facing each other. The first sealing member 20 and the second sealing member 30 in the sandwich device 2 are ultrathin substrates, and brittle materials such as glass and crystal are used. Therefore, the strength of the central portion (the region where the outer frame portion 14 does not exist in the piezoelectric vibrating plate 10) of the sandwich device 2 becomes particularly weak. In such a sandwich device 2, if the sheet thermistor 5 is disposed in the region of the central portion of the sandwich device 2, the first sealing member 20 may be broken by the pressing force when the sheet thermistor 5 is mounted.

In contrast, by joining the sheet thermistor 5 to the outer peripheral portion of the sandwich device 2 (the region where the outer frame portion 14 of the piezoelectric vibrating plate 10 exists), that is, disposing the end portion of the sheet thermistor 5 so as to overlap the outer frame portion 14, it is possible to prevent the first sealing member 20 from being broken and to secure the strength of the device 1. In particular, by overlapping the sheet thermistor 5 with the sealing portion (sealing pattern such as the vibration side first bonding pattern 113) of the sandwich element 2, the strength of the present element 1 can be further stabilized. In fig. 1 and 2, the two ends of the sheet thermistor 5 are arranged to overlap the outer frame 14 on the two sides facing each other in the short side direction of the sandwich element 2, but the two sides facing each other in the long side direction of the sandwich element 2 may be arranged to overlap the outer frame 14. Or the sheet thermistor 5 may be configured to overlap not only on two sides of the sandwich device 2 opposite to each other, but also on three sides or four sides.

The sheet thermistor 5 is mounted on the sandwich device 2 in a state in which the split electrode 53 is set as a bottom surface (surface to be bonded to the sandwich device 2) and the split electrode 53 is electrically bonded to the electrode pattern 211 of the first sealing member 20. In this case, it is preferable to adopt a structure in which the divided electrodes 53 and the electrode patterns 211 are electrically bonded to each other by a conductive resin adhesive 61 (see fig. 2). However, the present invention is not limited thereto, and the split electrodes 53 and the electrode patterns 211 may be bonded by Au (gold) bumps. Further, it is preferable that a non-conductive resin adhesive 62 (see fig. 2) is filled in a gap (a gap where the conductive resin adhesive 61 does not exist) between the sheet thermistor 5 and the sandwich element 2. The nonconductive resin adhesive 62 may be filled not only in the bottom surface of the sheet type thermistor 5 but also as a sealing resin for sealing the entire sheet type thermistor 5. Further, as the conductive resin adhesive 61, a silicone-based resin is preferably used; as the nonconductive resin adhesive 62, an epoxy resin is preferably used.

In this way, when the sheet thermistor 5 is surface-bonded to the sandwich element 2 by the conductive resin adhesive 61 and the nonconductive resin adhesive 62, the thermal conductivity between the sheet thermistor 5 and the sandwich element 2 can be improved. Thus, the temperature of the sheet thermistor 5 can be kept close to the temperature of the vibration portion 13 of the sandwich element 2. In addition, the surface bonding between the sandwich device 2 and the sheet thermistor 5 has the advantage of being able to increase the strength of the present device 1.

In the case where the sheet thermistor 5 is bonded by the electrically conductive resin adhesive 61 and the electrically non-conductive resin adhesive 62, the electrically conductive resin adhesive 61 preferably has a higher thermal conductivity than the electrically non-conductive resin adhesive 62. This can improve the thermal conductivity between the sheet thermistor 5 and the sandwich element 2. In addition, it is preferable that the hardness of the nonconductive resin adhesive 62 is higher than the hardness of the conductive resin adhesive 61. This can relieve the stress between the sheet thermistor 5 and the sandwich element 2, and can improve the package strength of the present element 1.

The embodiments disclosed herein are examples of various aspects, and do not constitute a basis for limiting the explanation. Accordingly, the technical scope of the present invention should not be interpreted based on the above embodiments, but should be defined based on the description of the claims. The present invention includes all modifications within the meaning and scope equivalent to the claims.

For example, the present device 1 described above is configured such that the chip thermistor 5 is mounted on the sandwich device 2, and the device is used as a piezoelectric vibrator, but may be used as a piezoelectric oscillator in which an IC chip is further mounted on the chip thermistor 5.

< Second embodiment >

Hereinafter, other embodiments of the present invention will be described in detail with reference to the accompanying drawings. In this embodiment, a case where the piezoelectric vibration device with a thermistor of the present invention is applied to a crystal vibration device with a thermistor will be described as an example. In the second embodiment, the same reference numerals are used for members having the same functions and structures as those of the piezoelectric vibration device with thermistor 1 according to the first embodiment (even if the shapes illustrated in the drawings are different).

As shown in fig. 10, the crystal vibration device with a thermistor according to the present embodiment includes a crystal vibration device Xtl and a thermistor (corresponding to the sheet-type thermistor 5), and as shown in fig. 10, the crystal vibration device Xtl includes a crystal vibrating reed (corresponding to the piezoelectric vibrating plate 10), a first sealing member 20, and a second sealing member 30, which are laminated in this order. And, the thermistor 5 is electrically coupled to the top surface of the crystal vibration device Xtl.

The piezoelectric vibrating plate 10 is constituted by an AT-cut crystal vibrating plate, and has a rectangular plate shape as a whole. The piezoelectric vibrating plate 10 includes: the vibration unit 13, holding units 15 connected to both corner portions of the vibration unit 13, holding units 15t, and an outer frame 14 disposed on the outer periphery of the vibration unit and connected to the holding units 15 and 15 t. Further, a penetrating portion 17 is formed between the vibrating portion 13 and the outer frame portion 14 in addition to the holding portion 15 and the holding portion 15t in the circumferential direction.

The vibrating portion 13 is rectangular having long sides opposite to each other and short sides opposite to each other, and having four corner portions. The vibration portion may have a square shape in plan view. A first excitation electrode 111 and a second excitation electrode 121 having rectangular shapes are formed on one principal surface and the other principal surface (front and back principal surfaces) of the substantially central portion of the vibration portion 13. The first extraction electrode 112 and the second extraction electrode 122 in the form of a belt are connected to the corner portions of the first excitation electrode 111 and the second excitation electrode 121, respectively, and extracted toward both ends of one side (corner portions of the vibrating portion). The first extraction electrode 112 is extracted to the outer frame 14 via the holding portion 15, and the second extraction electrode 122 is extracted to an external electrode terminal 321a and an external electrode terminal 321b formed on the second sealing member 30, which will be described later, via the holding portion 15 t.

Specifically, the first extraction electrode 112 is extracted from the surface of the holding portion 15 to the other main surface via a metal through hole (penetrating metal) V1 formed in the outer frame portion 14, and is connected to a metal through hole V2 formed in the second sealing member 30 described later. The metal through hole V2 is electrically connected to the external electrode terminal 321a formed on the other main surface of the second sealing member 30. The second extraction electrode 122 is extracted from the back surface of the holding portion 15t to the other surface of the piezoelectric vibrating plate 10, and is electrically connected to the metal through hole V3 formed in the second sealing member 30 facing each other. In addition, the metal through hole V3 is electrically connected to the external electrode terminal 321b formed on the other main surface of the second sealing member 30.

The first excitation electrode 111, the second excitation electrode 121, the first extraction electrode 112, and the second extraction electrode 122 are formed of a multilayer metal film, for example, a multilayer structure in which a Ti film is formed in contact with the piezoelectric vibrating plate 10 and then an Au film is formed on the upper portion thereof. As a specific example of the thickness of each metal film, for example, the Ti film is 5nm and the au film is 200nm, but these thicknesses may be changed according to desired characteristics.

A thick portion 13a is formed on one side of the vibration portion 13. The thick portion 13a is located on an edge of one end in the X-axis direction, and extends in the Z' -axis direction so as to occupy the entirety of the edge. The thick portion 13a has a thickness larger than that of the vibration portion 13.

As shown in fig. 11, a holding portion 15 is provided at one corner portion C1 of the vibrating portion 13; a holding portion 15t is provided at the other corner portion C2 of the vibrating portion 13. The holding portions 15 and 15t are connected to the outer frame 14. In this embodiment, the vibration portion, the holding portion, and the frame portion are integrally formed with the crystal plate by using a photolithography technique and a wet etching technique. But dry etching techniques may be used instead of wet etching.

As shown in fig. 10 and 13, the holding portion 15 is thicker than the vibrating portion 13 and the thick portion 13a, and a tapered portion T2 having a slope shape is formed from the thick portion 13a to the top surface of the holding portion 15; a tapered portion T3 having a slope shape is also formed from the vibration portion 13 to the holding portion 15. The holding portion 15 is connected to the outer frame 14, and a tapered portion T1 is formed from the holding portion 15 to the top surface of the outer frame 14. Based on such a structure, the thickness of each portion is set as: the vibration part is smaller than the thick part, the holding part is smaller than the frame body. The thickness of the thick portion 13a and the thickness of the holding portion 15 may be equal to each other. By forming each tapered portion, the boundary region can be made obtuse. In addition, when the risk of a short line is low, such as a small difference in height of the boundary region, the taper portion is not formed, and there is no problem in practical use.

Specific examples of the size of the piezoelectric vibrating plate 10 are as follows. The piezoelectric vibrating plate 10 uses a rectangular AT cut wafer having an external shape of 1.2mm wide and 1.0mm long; the external dimension of the vibration part 13 is 0.7mm wide and 0.7mm long; the outer frame 14 has a size of 0.2mm wide and 0.1mm long; the dimensions of the holding portion 15 were 0.05mm wide and 0.15mm long, and the thickness of each member was as follows: the thickness of the outer frame portion 14 was 0.04mm, the thickness of the holding portion 15 was 0.03mm, the thickness of the thick portion 13a was 0.017mm (17 μm), and the thickness of the vibrating portion 13 was 0.005mm (5 μm). In addition, from the viewpoint of securing mechanical strength, it is preferable that the thickness of the thick portion 13a is greater than the thickness of the vibration portion 13 by more than ten μm.

In the present embodiment, only one main surface of the piezoelectric vibrating plate 10 is thinned, and for example, only one main surface side is thinned to a desired frequency (thickness) by etching. In this case, since the other main surface side is not etched, deterioration of vibration characteristics due to surface roughening by etching can be prevented. However, a structure in which both main surfaces are thinned may be adopted.

Sealing films (corresponding to the vibration-side first bonding pattern 113 and the vibration-side second bonding pattern 123) are formed on the front and rear outer peripheral ends of the outer frame 14 in the circumferential direction, and these sealing films have a multilayer structure in which a Ti film is formed in contact with the piezoelectric vibrating plate 10, and an Au film is formed on the upper portion thereof, as in the electrode films described above.

Further, connection electrodes 141 and 142 are formed on the inner peripheral side of the outer frame 14 at positions distant from the holding portion 15. The connection electrodes 141 and 142 are each formed of a band-shaped metal film extending from the top surface of the outer frame 14 to the bottom surface of the outer frame 14 via the inner side surface of the outer frame 14. The connection electrodes 141 and 142 are electrically connected to electrode pads (corresponding to the divided electrodes 53) of the thermistor 5, which will be described later, and are electrically connected to the external electrode terminals 321c and 321d of the second sealing member 30.

The first sealing member 20 is formed of an AT cut quartz piece having a rectangular plate shape, and has the same shape and size as the piezoelectric vibrating plate 10. A sealing film (corresponding to the sealing-side first bonding pattern 221) corresponding to the vibration-side first bonding pattern 113 is formed on the other main surface (surface facing the piezoelectric vibrating plate 10) of the first sealing member 20 in the circumferential direction.

A pair of rectangular electrode pads (corresponding to the electrode pattern 211) having long sides and short sides are juxtaposed on one main surface of the first sealing member 20, and each electrode pad 211 is led out from the connection electrode 211a to the other main surface via a metal through hole.

The second sealing member 30 is formed of an AT cut quartz piece having a rectangular plate shape, and has the same shape and size as the piezoelectric vibrating plate 10. A sealing film (corresponding to the sealing side second bonding pattern 311) corresponding to the vibration side second bonding pattern 123 is formed on the surface of the second sealing member 30 facing the piezoelectric vibrating plate 10 in the circumferential direction.

Further, external electrode terminals 321a to 321d are formed on the surface of the second sealing member 30 not facing the piezoelectric vibrating plate 10. The external electrode terminals 321a to 321d are rectangular and formed at the corners of the second sealing member 30, respectively. The external electrode terminals 321a and 321b are electrically connected to the first excitation electrode 111 and the second excitation electrode 121, respectively, and the external electrode terminals 321c and 321d are electrically connected to the terminal 53 of the thermistor 5, respectively. The metal film constituting the external electrode terminals 321 has a laminated structure of a Ti film, a NiTi film, and an Au film.

In addition, a metal through hole V2 penetrating the front and rear surfaces is formed near the region of the second seal member 30 corresponding to the holding portion 15, and is electrically connected to the metal through hole V1. In addition, a metal via V3 penetrating the front and rear surfaces is formed near the region corresponding to the holding portion 15 t. With such a structure, the first lead electrode 112 formed on the piezoelectric vibrating plate 10 can be connected to the external electrode terminal 321a via the metal via hole V2, and the second lead electrode 122 can be connected to the external electrode terminal 321b via the metal via hole V3. Further, metal through holes V4 and V5 are formed corresponding to the connection electrodes 141 and 142, respectively, and the metal through holes V4 and V5 are electrically connected to the external electrode terminals 321c and 321d, respectively. With this configuration, the external electrode terminals 321a and 321b for the crystal oscillator and the external electrode terminals 321c and 321d for the thermistor are arranged on the long side and face each other. By changing the design of the electrode wiring, two external electrode terminals (321 a, 321 b) for the crystal oscillator Xtl and two external electrode terminals (321 c, 321 d) for the thermistor may be diagonally arranged.

The thermistor 5 is electrically and mechanically connected to the two electrode pads 211 of the first sealing member 20. The thermistor 5 is a rectangular plate-shaped NTC thermistor, a rectangular plate-shaped thermistor element (corresponding to the thermistor sheet 51) has a thickness G2, a common electrode 52 is formed on the entire surface of one main surface of the thermistor element 51, and two rectangular electrode pads 53 are formed on the other main surface of the thermistor element 51 and are spaced apart from each other by a predetermined interval G1 in the longitudinal direction of the thermistor element 51.

In the thermistor 5, two electrode pads 53 formed on the thermistor element 51 constitute terminals as resistors, and a conductive path leads from one electrode pad 53 to the other electrode pad 53 via the common electrode 52. With this structure, since the cross-sectional area of the conductive path is greatly increased and a path is formed between the surfaces of the two electrode pads 53 and the common electrode 52 facing each other, the resistance value is reduced in a small area, and it is easy to stabilize the characteristics and to increase the withstand voltage.

However, in the case of adopting a structure in which the two electrode pads 53 are close to each other, the conductive path is governed by the flow path between the two electrode pads 53, and a desired resistance value may not be obtained in some cases, depending on the applied voltage. Therefore, in the implementation, the distance G2a between one electrode pad 53 and the common electrode 52, the distance G2b between the other electrode pad 53 and the common electrode 52, and the distance G1 between the two electrode pads 53 are set to satisfy the relationship g2a+g2b < G1. Based on such a setting, a desired resistance value can be obtained, and the accuracy of the thermistor can be stabilized.

The larger the contact area between the thermistor 5 and the crystal oscillator Xtl is, the more accurate the temperature of the crystal oscillator Xtl can be detected. Therefore, it is preferable that the area of the two electrode pads 53 formed on the thermistor 5 is large relative to the thermistor 5. However, if the size is too large, short-circuiting between adjacent electrode pads or short-circuiting due to the conductive bonding material is likely to occur. If the contact area is small, the temperature detection accuracy of the crystal vibration device Xtl may be lowered. Therefore, the total area of the electrode pads 53 is set to 40% to 85% of the area of the thermistor 5 depending on the desired resistance value, and stable temperature detection can be realized. If the total area is 40% or less, the electrode pad of the thermistor 5 is too small to accurately detect the temperature information of the crystal oscillator Xtl, and if the resistance value is too high, the temperature detection performance of the thermistor 5 may be degraded. If the total area is 85% or more, the risk of short-circuiting including the conductive bonding material increases, and if short-circuiting occurs, the function of the thermistor 5 becomes ineffective.

Specific dimensional examples are shown below. The external dimensions of the thermistor 5 (the external dimensions of the thermistor element 51) are: the long side is 0.8mm, the short side is 0.6mm, the thickness is 0.05mm, and the area is 0.48mm ². The external dimensions of each electrode pad 53 formed on the thermistor element 51 are: the long side was 0.52mm (short side of the thermistor element 51), the short side was 0.3mm (long side of the thermistor element 51), and the area was 0.156mm ². With such a configuration, the total area of the electrode pads 53 is set to about 65% of the area of the thermistor 5, and the distances G2a and G2b between the electrode pads 53 and the common electrode 52 are set to 0.05mm, respectively; the distance G1 between the electrode pads 53 is 0.12mm, and the g2a+g2b < G1 holds.

Other specific examples are shown below. The external dimensions of the thermistor 5 (the external dimensions of the thermistor element 51) are: the long side is 0.7mm, the short side is 0.6mm, the thickness is 0.04mm, and the area is 0.42mm ². In addition, the external dimensions of each electrode pad 53 formed on the thermistor element 51 are: the long side is 0.58mm (the short side of the thermistor element 51), the short side is 0.3mm (the long side of the thermistor element 51), and the area is 0.174mm². With this configuration, the total area of the electrode pads 53 is set to be about 83% of the area of the thermistor 5, and the distances G2a and G2b between the electrode pads 53 and the common electrode 52 are set to be 0.04mm, the distance G1 between the electrode pads 53 is set to be 0.09mm, and the above-mentioned g2a+g2b < G1 holds. The above-mentioned dimensions may be appropriately designed according to the dimensions and characteristics of the crystal oscillator Xtl or the specifications of the crystal oscillator with a thermistor.

The plate-like thermistor is obtained by forming a paste of, for example, an mn—fe—ni based material together with an adhesive, forming a green sheet of a thermistor wafer by using a thick film forming technique such as a screen printing technique or a doctor blade technique, and sintering the green sheet into a plate-like thermistor wafer by a firing technique.

An electrode film (metal film) is formed on the plate-like thermistor wafer by sputtering, and is patterned by a photolithography technique. As a specific metal material, a laminated structure in which a Ti film, a NiTi film, and an Au film are laminated may be used, as in the metal film constituting the terminal electrode, or another metal film structure may be used. In the case of using the laminated structure in which the Ti film, niTi film, and Au film are laminated, when finally soldering the sheet-type thermistor to the mounting substrate, the conductive bonding can be stably performed, and solder corrosion is less likely to occur. The metal film structure of the two electrode pads 53 may be different from the metal film structure of the common electrode 52, and for example, the metal film structure of the two electrode pads 53 may be a laminated structure in which the Ti film, the NiTi film, and the Au film are laminated, and the metal film structure of the common electrode 52 may be a laminated structure in which the Ti film and the Au film are laminated.

In this way, a thin film forming method such as sputtering forms a metal film as the two electrode pads 53 and the common electrode 52 on the single-layer plate-like thermistor element 51, thereby obtaining an ultra-thin plate-like thermistor. In addition, the roughness of the plate-like thermistor surface can be reduced by grinding and polishing the surface of the thermistor wafer. With such a configuration, the electrode film (metal film) can be stably formed, and the manufacturing accuracy can be improved, so that the performance of the thermistor 5 can be improved in accuracy.

As shown in fig. 13, the crystal oscillator Xtl has a structure in which the first sealing member 20, the piezoelectric vibrating plate 10, and the second sealing member 30 are stacked in this order. As described above, these members are made of crystal pieces, and the surfaces thereof are mirror polished to smooth surfaces. As a specific example, it is preferable that the average surface roughness ra=0.3 to 0.1nm. By forming the sealing film on such a smooth surface, the metal film (uppermost Au film) on the surface thereof also becomes a very smooth surface state.

The bonding of the first sealing member 20 and the piezoelectric vibrating plate 10 and the bonding of the piezoelectric vibrating plate 10 and the second sealing member 30 are achieved by performing surface treatment on Au of the metal film and then press-bonding the two by diffusion bonding. Thus, the vibrating portion 13 of the piezoelectric vibrating plate 10 is hermetically sealed by the sealing portions S1 and S2 formed by joining the sealing films together in a state surrounded by the first sealing member 20, the second sealing member 30, and the outer frame portion 14. The hermetically sealed interior is a vacuum or inert gas atmosphere.

The thermistor 5 is mounted on the top surface of the crystal vibration device Xtl having the above-described structure, i.e., on one main surface of the first sealing member 20. Specifically, the electrode pads (211 ) formed on the top surface of the crystal vibration device Xtl and the electrode pads (53, 53) formed on the thermistor 5 composed of a plate-like thermistor are surface-bonded by a conductive bonding material (for example, a conductive resin adhesive 61) (R1, R1). Since the electrode pads (211 ) have a larger area than the electrode pads (53, 53), the conductive bonding materials (R1, R1) can electrically bond the crystal oscillator Xtl to the thermistor 5 with rounded corners, and the bonding strength between the two can be improved. The conductive bonding material R1 is formed by adding an electrically conductive filler such as silver powder or silver flake to a paste-like silicone resin bonding material, and has excellent thermal conductivity. As a result, the electrode pads are surface-bonded to each other, and the thermal conductivity is good, so that the thermistor 5 can accurately detect the temperature of the crystal oscillator Xtl with less time delay. In the case where the conductive bonding material R1 is the conductive resin adhesive 61, another resin such as a urethane resin or an epoxy resin other than silicone resin may be used. The conductive bonding material R1 is not limited to the conductive resin adhesive 61, and may be solder.

As shown in fig. 13, in the present embodiment, a thermistor 5 constituted by a plate-like thermistor is covered with a resin material R2. In the structure in which the resin material R2 covers the top surface of the crystal oscillator Xtl, electrode pads (211 ) provided on the thermistor 5 and the crystal oscillator Xtl, and the conductive bonding material R1 are also covered with the resin material R2. The resin material R2 used here is formed by adding a silica (SiO ₂) filler to an epoxy resin, and has a lower thermal conductivity than the conductive bonding material R1. The resin material R2 may be a polyurethane resin other than epoxy resin, a silicone resin, or another resin material. With such a structure, heat detected by the thermistor 5 can be prevented from being emitted to the outside.

With the above configuration, the thermistor 5 can detect the temperature change of the crystal oscillator Xtl with a small time delay via the electrode pads 211 and 53 and the conductive bonding material R1. Further, since the thermistor 5 is covered with the resin material having a lower thermal conductivity than the conductive bonding material, the heat absorbed by the thermistor 5 is not leaked to the outside. This allows accurate detection of the temperature at which crystal oscillator Xtl is operating, and thus allows accurate temperature detection. In addition, the top surface of the crystal oscillator Xtl may be provided with an IC component having an oscillation circuit and a temperature compensation circuit in addition to the thermistor 5, and may be electrically connected to the crystal oscillator Xtl and the thermistor 5. With this configuration, a crystal oscillator device constituting a temperature-compensated crystal oscillator can be obtained.

According to the present embodiment, in the vibration portion 13, a thick portion 13a is formed along almost the entire region of the side where one end of the holding portion 15, 15t is formed; the other end side has a thickness of the thin vibrating piece corresponding to the high frequency. Therefore, vibration excited by the vibration portion 13 can be performed in a state less susceptible to the boundary conditions due to the thick portion 13 a. Thus, the piezoelectric vibrating plate 10 in which the CI value (series resonance resistance) can be maintained in a good state is obtained while suppressing occurrence of spurious and the like. Further, the thick portion 13a can also improve the mechanical strength of the vibration portion 13.

As described above, the thickness of the holding portion 15 is greater than or equal to the thickness of the thick portion 13a, and tapered portions are formed between the outer frame portion 14 and the holding portion 15, and between the thick portion 13a and the vibration portion 13. As described above, the formation of the tapered portion can make the boundary obtuse. Therefore, the first extraction electrode 112 and the second extraction electrode 122 which are extracted from the first excitation electrode 111 and the second excitation electrode 121 to the side of one end of the piezoelectric vibrating plate 10 are formed on the tapered portion without passing through the corner portion region (step portion) of the acute angle, and thus, the reduction of the conduction performance of the electrode and the disconnection of the electrode can be prevented. Thus, the piezoelectric vibrating plate 10 having good electrical characteristics can be obtained.

According to the present embodiment, the outer frame portion 14 and the vibration portion 13 are connected by a plurality of holding portions (15, 15 t), but the thickness of the holding portion 15t is smaller than the thickness of the holding portion 15. In this way, the mechanical strength can be stabilized by holding the vibration plate by the plurality of holding portions, and the vibration of the vibration portion can be prevented from being hindered by providing the holding portion having a small thickness (thin). This suppresses a decrease in the electrical characteristics of crystal oscillator Xtl, and ensures practical electrical performance. In addition, the present embodiment is not limited to this, and a configuration may be adopted in which only one portion of the holding portion 15 is connected to the vibration portion 13.

In the piezoelectric vibrating plate 10, the through-hole 17 may be replaced with a thin portion. In this case, the vibration portion is connected to the frame portion via the holding portion and the thin portion.

In the present embodiment, the metal films of the first excitation electrode 111 and the second excitation electrode 121 and the sealing metal film (i.e., the sealing film) are exemplified by a multilayer structure of Ti and Au, but the present invention is not limited to the metal film of this structure. For example, ti, niTi, au may be used.

The first sealing member 20 and the second sealing member 30 are bonded to the piezoelectric vibrating plate 10 by diffusion bonding, but for example, soldering using AuSn alloy solder may be used, or soldering using other solders such as Sn alloy solder may be used. In the case of using such brazing, the metal film may have a different structure, for example, a structure in which an Ag or Cu film is formed on a Cr base layer, or a structure in which an alloy film with Au is formed.

In the above description, the water crystal plate is used as the material of the first seal member 20 and the second seal member 30, but a glass material or a ceramic material may be used instead of the water crystal plate. In addition, although only a plate-like structure is illustrated as an example of the shape, a concave portion may be provided at a position facing the piezoelectric vibrating plate 10. In the case where the concave portion is provided, the chance of contact between the vibration portion 13 and the first seal member 20 and the second seal member 30 can be reduced, and the characteristics of the crystal vibrator Xtl can be stabilized.

A modification of the present second embodiment will be described with reference to fig. 16. The detailed structure of the crystal vibration device Xtl is omitted in fig. 16. Although the thermistor 5 is mounted on the top surface of the crystal oscillator Xtl, the thermistor 5 is different in structure and arrangement.

On the top surface of the first sealing member 20, two electrode pads 24 are formed. Unlike the example of fig. 13, the two electrode pads 24 are formed to be left when viewed facing the drawing. As a result, a region where the electrode pad 24 is not formed can be secured on the top surface of the first sealing member 20. This region can be used as the adjustment region 25. When the first sealing member 20 is made of a light-transmitting material, the adjustment region 25 is permeable to an energy beam B such as laser light. Therefore, by irradiating the metal films formed on the piezoelectric vibrating plate 10 with the energy beam to remove a part of the metal films, the frequency of the crystal vibration device Xtl can be adjusted.

Further, by forming a metal film for adjustment in advance inside the first sealing member 20, irradiating the metal film for adjustment with an energy beam, and vaporizing the metal film for adjustment to attach the metal film formed on the piezoelectric vibrating plate 10, the frequency of the crystal vibrating device Xtl can be adjusted.

The thermistor 5 is configured such that an electrode film is not formed on one main surface of the thermistor element, two electrode pads 54 are formed on the other main surface of the thermistor element, and an inter-electrode gap G3 is formed. Therefore, a conductive path is formed between the two electrode pads 54, and functions as a thermistor.

By bonding the two electrode pads 54 and the two electrode pads 24 with the conductive bonding material R1 composed of solder, the two electrode pads realize conductive surface bonding, and thereby the two can be bonded in a state of good thermal conductivity. In the example of fig. 16, an insulating resin material R3 having good thermal conductivity is filled between the conductive bonding material R1 and the conductive bonding material R1. With these structures, the other main surface of the thermistor 5 is in a state where the entire surface is bonded to the crystal oscillator Xtl.

The resin material R2 is formed to cover the entire top surface (one main surface) of the first seal member 20. Thereby, the entire thermistor 5 is covered with the resin material R2. The resin material R2 may be formed only in the mounting region of the thermistor 5. In this case, since the adjustment region 25 is not covered with the resin material R2, there is an advantage in that frequency adjustment can be performed by the energy beam B after the thermistor is bonded.

According to the present embodiment, since the thermistor 5 is bonded to substantially the entire other main surface of the crystal oscillator Xtl by the conductive bonding material (solder) R1 and the insulating resin material R3, the temperature change of the crystal oscillator Xtl can be reliably and accurately detected by the thermistor 5. In addition, by covering with the resin material R2, heat emission can also be suppressed. With this configuration, a crystal oscillator with a thermistor capable of performing high-precision temperature detection can be obtained. Further, after the airtight sealing or after the mounting of the thermistor 5, the frequency of the crystal oscillator Xtl can be adjusted by the adjustment region 25, so that the electrical characteristics can be improved.

The structure covered with the resin (resin material R2) in the second embodiment may be naturally combined with the piezoelectric vibration device with a thermistor 1 of the first embodiment.

The present application claims priority based on Japanese patent application No. 2021-178744, which was invented by Japanese patent application No. 2021, 11, 1 and No. 2021, 11, 1, and Japanese patent application No. 2021-178745. It goes without saying that all the contents thereof are imported into the present application.

< Description of reference numerals >

1. Piezoelectric vibration device with thermistor

2. Sandwich device (piezoelectric vibration device of sandwich structure)

10. Piezoelectric vibrating plate

11 First main surface (of piezoelectric vibrating plate)

111. First excitation electrode

112. First lead-out wiring

113. Vibration side first bonding pattern

114-116 Bonding patterns for connection

12 Second main surface (of piezoelectric vibrating plate)

121. Second excitation electrode

122. Second lead-out wiring

123. Vibration side second bonding pattern

124. 125 Joint pattern for connection

13. Vibration part

14. Outer frame

15. Holding part

16. Through hole

20. First sealing member

21 First major face (of first sealing member)

211. Electrode pattern

212. 213 Wiring pattern

22 A second major face (of the first sealing member)

221. Sealing side first bonding pattern

222 To 225 bonding patterns for connection

226. Wiring pattern

23. Through hole

30. Second sealing member

31 First major face (of second sealing member)

311. Sealing side second bonding pattern

312. Bonding pattern for connection

32 A second main surface (of the second sealing member)

321. External electrode terminal

33. Through hole

5. Sheet type thermistor

51. Thermistor sheet

52. Common electrode

53. Divided electrode

61. Conductive resin adhesive

62. Non-conductive resin adhesive

S1, S2 sealing part

T1, T2, T3 taper

V1, V2, V3, V4, V5 metal vias

R1 conductive bonding material

R2 resin material

R3 insulating resin material

Claims

1. A piezoelectric vibration device with a thermistor, characterized in that:

a piezoelectric vibration device with a sandwich structure and a sheet thermistor,

The piezoelectric vibration device is configured such that, on a piezoelectric vibrating plate having a vibrating portion in which a first excitation electrode is formed on a first main surface and a second excitation electrode is formed on a second main surface, a first sealing member is laminated and joined so as to cover the first main surface side of the piezoelectric vibrating plate, and a second sealing member is laminated and joined so as to cover the second main surface side of the piezoelectric vibrating plate, thereby forming an internal space in which the vibrating portion is hermetically sealed;

the sheet thermistor is mounted on an outer surface of the first sealing member in the piezoelectric vibration device;

The sheet-type thermistor is configured to overlap at least a part of the vibration portion in a plan view.

2. The piezoelectric vibration device with a thermistor according to claim 1, characterized in that:

the sheet-type thermistor is configured to overlap the entirety of the first excitation electrode and the second excitation electrode in a plan view.

3. The piezoelectric vibration device with a thermistor according to claim 1, characterized in that:

The sheet-type thermistor is configured such that a common electrode is formed on one main surface of a single-piece thermistor sheet, and a divided electrode is formed on the other main surface, and the common electrode is formed on substantially the entire surface of the thermistor sheet.

4. The piezoelectric vibration device with a thermistor according to claim 1, characterized in that:

The sheet-type thermistor is configured such that a common electrode is formed on one main surface of a single-piece thermistor sheet, and a divided electrode is formed on the other main surface, and the divided electrode is formed in a portion that occupies half or more of the area of the thermistor sheet.

5. A piezoelectric vibration device with a thermistor, characterized in that:

The piezoelectric vibrating plate includes the vibrating portion, an outer frame portion surrounding an outer periphery of the vibrating portion, and a holding portion that holds the vibrating portion by connecting the vibrating portion to the outer frame portion;

The sheet-type thermistor is arranged to overlap the outer frame portions on both sides of the piezoelectric vibration device facing each other.

6. The piezoelectric vibration device with a thermistor according to claim 1 or 5, characterized in that:

the sheet type thermistor and the piezoelectric vibration device are electrically connected by a conductive resin adhesive, and a gap between the sheet type thermistor and the piezoelectric vibration device is filled with a nonconductive resin adhesive.

7. The piezoelectric vibration device with a thermistor according to claim 6, characterized in that:

the conductive resin adhesive has a higher thermal conductivity than the non-conductive resin adhesive.

8. The piezoelectric vibration device with a thermistor according to claim 6, characterized in that:

The hardness of the non-conductive resin adhesive is higher than the hardness of the conductive resin adhesive.

9. The piezoelectric vibration device with a thermistor according to claim 1 or 5, characterized in that:

the first sealing member and the second sealing member are formed of a brittle material.