JP3171273B2 - Piezo components - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piezoelectric component used as, for example, a filter, a resonator or an oscillator.

[0002]

2. Description of the Related Art As a prior art relating to this kind of piezoelectric component, there is known a structure in which a piezoelectric substrate and a supporting substrate having a concave portion are bonded together via an adhesive. In addition, when the piezoelectric substrate and the support substrate are bonded using an adhesive, a technique of extending a part of the adhesive to an inner wall surface of a vibration space formed by the piezoelectric substrate and the support substrate and damping spurious is also available. Are known.

[0003]

However, when a structure is adopted in which the piezoelectric substrate and the supporting substrate having the concave portion are bonded via an adhesive, it is difficult to control the amount and area of application of the adhesive. Hangs into the inside of the vibration space, so that a required vibration space cannot be formed, or a problem such as being attached to the vibrating portion and causing a vibration obstacle is likely to occur.

[0004] Even if the amount and area of application of the adhesive can be made constant, it is necessary to avoid the generation of voids in the adhesive layer and to obtain the necessary adhesive force by connecting the piezoelectric substrate to the support substrate. Since it is necessary to take a step of applying pressure between the two to bond them together, the adhesive drips into the vibrating space due to the pressing force, and the required vibrating space cannot be formed, or the adhesive adheres to the vibrating portion. Vibration may occur.

Further, when a structure is adopted in which a part of the adhesive extends on the inner wall surface of the vibration space formed by the piezoelectric substrate and the supporting substrate to dampen spurious components, the adhesive protrudes from a predetermined area. However, there has been a problem that the vibration of the main frequency band is also damped.

Therefore, an object of the present invention is to solve the above-mentioned conventional problems, to prevent the adhesive from dripping into the cavity, and to have a structure capable of reliably forming a vibration space having a required space volume. It is to provide a piezoelectric component.

[0007]

In order to solve the above problems, a piezoelectric component according to the present invention has a piezoelectric substrate, a front cover, and a back cover. The piezoelectric substrate has a vibrating part, and the vibrating part includes a front electrode and a back electrode which are arranged on a front surface and a back surface so as to face each other. Each of the front cover and the back cover has a cavity layer and a sealing layer. The cavity layer has a cavity on one side, and the cavity has an opening on the one side and a ceiling surface on the other side,
The ceiling surface has a through hole having a diameter smaller than the inner diameter of the hollow portion in a substantially central portion thereof , and the one surface side is adhered to the front surface or the back surface of the piezoelectric substrate, and the vibration space by the hollow portion is formed around the vibrating portion. Has formed. The sealing layer has an adhesive layer and an outer layer.
And a plate member. One side of the adhesive layer is formed of the hollow layer.
A cut glued to the other side and overlapping the cavity area
It has a hollow recess. The outer plate member has a flat shape.
The adhesive layer is adhered to almost the entire other surface of the adhesive layer,
The part is closed .

[0008]

The piezoelectric substrate includes a front electrode and a back electrode whose vibrating portions are disposed on the front and back surfaces of the piezoelectric substrate. The front cover and the back cover each have a cavity on one side and the one surface has a front surface of the piezoelectric substrate. The cavity part forms a vibration space around the vibrating part, and the sealing layer is adhered to the other surface side of the cavity layer. can get.

[0009] The cavity layer has a cavity portion opened on one side and a ceiling surface on the other side, and the ceiling surface has a through hole having a diameter smaller than the inner diameter of the cavity approximately at the center. Therefore, the cavity has a cross-sectional shape having an overhang. Therefore, when the sealing layer is adhered to the cavity layer, the overhang portion prevents the adhesive from flowing into the cavity. In addition, the adhesive layer constituting the sealing layer is cut out so as to overlap with the cavity area.
Since the outer plate member of the sealing layer is pressurized and bonded to the cavity layer, the outer plate member does not press the adhesive on the cavity portion because the outer plate member has the concave shape . For this reason, the deformation of the cavity is prevented, and the adhesive does not drip into the cavity. Further, the outer plate member has a flat shape.
The adhesive layer is adhered to almost the entire other surface of the adhesive layer,
Because the parts are closed, create a closed vibration space.
Can be.

Further, when a structure for damping spurious components with an adhesive is used, damping for vibrations in the main frequency band can be minimized, and damping can be selectively and reliably applied to predetermined spurious components.

[0011]

FIG. 1 is an exploded perspective view of a piezoelectric component according to the present invention.
2 is a perspective view in the assembled state, FIG. 3 is a front partial cross-sectional view, FIG. 4 is a front cross-sectional view, and FIG.
6 is a cross-sectional view taken along line A2-A2 in FIG. 1 is a piezoelectric substrate, 2 is a front cover, and 3 is a back cover.

The piezoelectric substrate 1 has front electrodes 61, 71 and back electrodes (62, 63), (72, 7) in which the vibrating portions 4, 5 are formed on the front and back surfaces of the piezoelectric substrate 1 so as to face each other.
3) is provided. The front electrodes 61 and 71 are commonly connected to the lead electrode 8. The capacitor electrodes 9 provided on both sides of the piezoelectric substrate 1 are also electrically connected to the lead electrodes 8.

The back electrodes 62 and 72 are electrically connected to each other via a capacitor electrode 10 facing the capacitor electrode 9, and the back electrodes 63 and 73 are piezoelectrically connected by lead electrodes 64 and 74 formed on the piezoelectric substrate 1. It is led to the ends of both corners of the substrate 1. Concerning the electrode arrangement, it is possible to adopt an arrangement relationship in which the electrodes (62, 63) and (72, 73) are used as front electrodes and the electrodes 61, 71 are used as back electrodes, contrary to the illustration.

The front cover 2 includes a hollow layer 21 and a sealing layer 22.
23, and the back cover 3 also includes a cavity layer 31 and sealing layers 32 and 33. The cavity layers 21 and 31 have cavity portions (211 and 21) at portions corresponding to the vibrating portions 4 and 5, respectively.
2) and (311 and 312) are adhered to the piezoelectric substrate 1. Cavities (211 and 212), (311 and 31)
2) has an opening on one side and a ceiling surface (2) on the other side.
13, 214) and (313, 314), and the ceiling surface (213, 214) and (313, 314) are hollow (2, 214).
11, 212) and (311, 312) have through holes (215, 216) and (315, 316) smaller in diameter than the inner diameters. Therefore, the cavities (211 and 212), (31)
1, 312) are ceiling surfaces (213, 214) and (31
3, 314) has a cross-sectional shape protruding as an overhang portion. One side of the cavity layers 21 and 31 is adhered to the front surface or the back surface of the piezoelectric substrate 1 to form a vibration space around the vibration portions 4 and 5 by the cavity portions (211 and 212) and (311 and 312). In forming the vibration space, resist is applied to the area of the vibration part by means such as printing,
The resin is dried, and then, for example, an ultraviolet-curable resin paint is applied by means of printing or the like, dried, and then the resist is dissolved and removed with a solvent to cure the resin layer. Thereby, a cavity layer is formed.

The sealing layers 22 and 23 constituting the front cover 2
Is formed by bonding an adhesive layer 22 and an outer plate member 23 together. The adhesive layer 22 is a synthetic resin adhesive, and is applied by means such as screen printing. Adhesive layer 22
Has concave portions 221 and 222 formed by through holes at portions corresponding to the hollow portions 211 and 212. The outer plate member 23 is made of ceramics such as alumina, and is formed by the adhesive force of the adhesive layer 22.
It is adhered on the cavity layer 21. Thereby, the cavity portions 211 and 212 of the cavity layer 21 are sealed.

The sealing layers 32 and 33 constituting the back cover 3
Also, like the sealing layer of the front cover 2, the adhesive layer 32 and the outer plate member 33 are attached to each other. The adhesive layer 32
Synthetic resin adhesive, applied by means such as screen printing. The adhesive layer 32 has the hollow portions 311 and 312
Have concave portions 321 and 322 formed by through holes. The outer plate member 33 is made of ceramics such as alumina, and is adhered on the cavity layer 31 by the adhesive force of the adhesive layer 32. Thereby, the cavity 311 of the cavity layer 31,
312 is sealed.

As described above, the piezoelectric substrate 1 has the vibrating sections 4 and 5
Are disposed on the front and rear surfaces of the front electrode 6 so as to face each other.
1 and 71 and back electrodes (62, 63) and (72, 73), and the front cover 2 and the back cover 3 have cavities (211 and 212) and (311 and 312) on one side. The side is overlapped and adhered to the front and back surfaces of the piezoelectric substrate 1,
The cavities (211 and 212) and (311 and 312) form a vibrating space around the vibrating portions 4 and 5, and the sealing layers (22, 2
3) and (32, 33) are adhered to the other surfaces of the hollow layers 21 and 31, so that the hollow portions (211 and 212) and (31)
According to (1, 312), a piezoelectric component having a required vibration space can be obtained.

The cavity layers 21 and 31 have a cavity (21).
1, 212) and (311, 312) are open on one side, and the ceiling surfaces (213, 214), (313,
314), and ceiling surfaces (213, 214), (31)
3, 314) are cavities (211, 212), (311,
312) Through holes (215, 216) smaller in diameter than the inner diameter,
(315, 316), the cavity (21
1, 212) and (311, 312) have a cross-sectional shape having an overhang. For this reason, when the sealing layers (22, 23) and (32, 33) are bonded to the hollow layers 21 and 31 (see FIGS. 9 and 10), the adhesive forming the bonding layers 22 and 32 includes the hollow portions ( 211, 212), (311, 31)
It is blocked by the overhang portion of 2) and does not flow into the cavity.

Moreover, the sealing layers (22, 23), (32,
33) are cavities (211 and 212), (311 and 31)
The recesses (221, 222) and (32)
1, 322), even when the sealing layers (22, 23) and (32, 33) are bonded to the cavity layers 21 and 31 by pressing (see FIG. 10), the sealing layers (22, 23) , (3
2, 33) are hollow parts (211, 212), (311, 3)
No adhesive is pressed on 12). Therefore, the deformation of the cavities (211 and 212) and (311 and 312) is prevented, and the adhesive forming the adhesive layers 22 and 32 is applied to the inside of the cavities (211 and 212) and (311 and 312). No more drooping.

In the figure, further, on the back side of the piezoelectric substrate 1,
A lead electrode 11 facing the front-side lead electrode 8 is provided. The lead electrode 8 on the front side and the lead electrode 11 on the back side are connected to each other by a conductor 12 passing through the piezoelectric substrate 1 in the front and back directions. The conductor 12 is a position that does not affect the main vibration mode, and any position or shape can be selected as long as the position can connect the lead electrodes 8 and 11 to each other. For example, a notch opening at the end of the piezoelectric substrate is provided,
The conductor 12 may be formed on the surface. Conductor 12 shown
Can be formed by attaching a conductor to the through holes provided in the piezoelectric substrate 1 at the same time as the lead electrodes 64, 74, 8, and 11 by a thin film technique such as sputtering or a thick film technique such as printing. The through holes can be formed by punching a green sheet before firing and by laser processing after firing. Front electrodes 61, 71, back electrodes (62, 63), (7
2, 73) and the lead electrodes 64, 74, 8, 11 can be formed by a thin film technique such as sputtering or a thick film technique.

A notch 41 is formed at one edge of the outer plate member 33.
To 43 are provided. External connection terminals 13 to 15 are attached to the insides of the cutouts 41 to 43 and the periphery thereof. The external connection terminals 13 to 15 are formed by a thick film forming technique, a plating technique, or a combination thereof. The lead electrodes 64, 11 and 74 provided on the back side of the piezoelectric substrate 11
The outer plate member 33 is arranged so as to face the external connection terminals 13 to 15 provided around the notches 41 to 43. Then, the conductive agent 16 to conductive material such as conductive paint is applied to the missing portions 41 to 43.
18 (see FIG. 2) is applied, and the lead electrodes 64, 11 and 74 are electrically connected to the external connection terminals 13 to 15.

As described above, the front electrodes 61 and 71 are electrically connected to the lead electrode 11 provided on the back side by the conductor 12 passing through the piezoelectric substrate 1 in the front and back directions, and the back electrodes 63 and 73 are provided on the back side. The outer plate member 33 has external connection terminals 13 to 15 on its outer surface, and the external connection terminals 13 to 15 are connected to the other lead electrodes 64 and 74.
Since it is electrically connected to 74, a cap-shaped terminal fitting made of a thin metal plate is not required. For this reason, the number of parts is reduced, and the structure for removing the vibrating portion is simplified. Since the cap-shaped terminal fitting is unnecessary, warpage of the cap-shaped terminal fitting,
The reliability does not decrease due to damage or the like.

Further, since the outer plate member 33 has external connection terminals 13 to 15 on its outer surface and the external connection terminals 13 to 15 are electrically connected to the lead electrodes 64, 11, 74, the outer plate member 33 is provided on the outer plate member 33. The external connection terminals 13 to 15 serve as external connection portions. Therefore, it is possible to prevent the lead electrodes 64, 11, 74 derived from the vibrating parts 4, 5 and formed of a thin film from being eroded by solder. Since the external connection terminals 13 to 15 of the outer plate member 33 can be formed as a thick film, the influence of solder erosion can be substantially ignored.

FIG. 6 is an exploded perspective view of still another embodiment of the piezoelectric component according to the present invention, and FIG. 7 is a sectional view thereof. In the drawings, the same reference numerals as those in FIGS. 1 and 2 indicate the same components. This embodiment is characterized in that the outer plate members 23 and 33 have the hollow portions (211 and 212) and (31).
1, 312) and corresponding recesses (231, 232), (3
31 and 332), and the same operation and effect as the embodiment of FIGS. 1 and 2 can be obtained.

[0025]

As described above, according to the present invention, the following effects can be obtained. (A) The piezoelectric substrate includes a front electrode and a back electrode in which a vibrating portion is disposed on the front and back surfaces of the piezoelectric substrate, and the front cover and the back cover each have a cavity on one surface side and the one surface has a front surface of the piezoelectric substrate. The cavity part forms a vibration space around the vibrating part, and the sealing layer is adhered to the other surface side of the cavity layer. Can be provided. (B) The cavity layer has a cavity portion opened on one surface side and a ceiling surface on the other surface side, the ceiling surface has a through-hole having a diameter smaller than the inner diameter of the cavity portion, and the sealing layer has a cavity portion. Since there is a concave portion in the corresponding portion, even when the sealing layer is pressed and bonded to the cavity layer, the required space volume is reduced without causing deformation of the cavity portion and dripping of the adhesive into the cavity portion. It is possible to provide a piezoelectric component that can reliably form a vibration space having the piezoelectric component. (C) When a structure is employed in which spurious vibrations are damped by an adhesive, it is possible to provide a piezoelectric component capable of minimizing damping for vibrations in the main frequency band and selectively and reliably damping predetermined spurious vibrations.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a piezoelectric component according to the present invention.

FIG. 2 is a front view of the piezoelectric component according to the present invention shown in FIG.

FIG. 3 is a front sectional view of the piezoelectric component according to the present invention shown in FIG. 1;

FIG. 4 is a sectional view taken on line A1-A1 of FIG. 3;

FIG. 5 is a sectional view taken on line A2-A2 of FIG. 3;

FIG. 6 is an exploded perspective view of another embodiment of the piezoelectric component according to the present invention.

FIG. 7 is a front sectional view of the piezoelectric component according to the present invention shown in FIG. 6;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Piezoelectric substrate 2 Front cover 21 Cavity layer 211, 212 Cavity part 213, 214 Ceiling surface 215, 216 Through hole 22 Adhesive layer 221, 222 Depression 23 Outer plate member 3 Back cover 31 Cavity layer 311 312 Cavity part 313, 314 Ceiling Surfaces 315, 316 Through holes 32 Adhesive layers 321, 322 Concave portions 33 Outer plate members 4, 5, Vibrating portions 61, 71 Front electrodes 62, 72, 63, 73 Back electrodes 64, 74 Lead electrodes

────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Yoshiju Yamashita 1-13-1 Nihonbashi, Chuo-ku, Tokyo Inside TDK Corporation (56) References JP-A-2-180417 (JP, A) 1-74623 (JP, U) Hikaru Hei 2-36221 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) H03H 9/02 H03H 9/56

Claims (1)

(57) [Claims] 1. A piezoelectric component having a piezoelectric substrate, a front cover, and a back cover, wherein the piezoelectric substrate has a vibrating portion, and the vibrating portion is disposed on a front surface and a back surface so as to face each other. A front electrode and a back electrode, wherein each of the front cover and the back cover has a cavity layer and a sealing layer, wherein the cavity layer has a cavity on one surface side; Has an opening on the one surface side and has a ceiling surface on the other surface side, the ceiling surface has a through hole having a diameter smaller than the inner diameter of the hollow portion in a substantially central portion thereof , and the one surface side has a surface of the piezoelectric substrate. Alternatively, a vibration space is formed by the cavity around the vibrating portion, which is adhered to the back surface, wherein the sealing layer includes an adhesive layer and an outer plate member, and the adhesive layer has one surface formed of the cavity layer. Glued to the other side
And has a cut-out recess overlapping the region of the cavity.
The outer plate member is in the form of a flat plate, and the other side of the adhesive layer
A piezoelectric component that is adhered to substantially the entire surface of the piezoelectric element and closes the recess .