JPH1065480A - Piezoelectric vibration parts - Google Patents

Abstract

(57) [Problem] To provide a piezoelectric vibration component having stable characteristics capable of securing vibration at a required frequency and suppressing unnecessary vibration that adversely affects characteristics at the same time. It is. SOLUTION: A vibrating electrode 2 is formed on both front and back surfaces of a piezoelectric substrate 1 so as to face each other with the piezoelectric substrate 1 interposed therebetween. An extraction electrode 3 is provided. In order to seal the vibration electrode 2 on the front and back surfaces of the piezoelectric substrate 1, a space 5 larger than the vibration electrode 2 and having irregularities on the outer periphery is formed on the surface of the sealing substrate 4 on the piezoelectric substrate 1 side. An adhesive layer 6 is formed. The space 5 is provided between a predetermined portion of the piezoelectric substrate 1 including the vibration electrode 2 and the sealing substrate 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chip-type piezoelectric vibration component such as an oscillator and a filter used in electronic equipment.

[0002]

2. Description of the Related Art Conventionally, piezoelectric vibrating parts have been disclosed in Japanese Patent Application Laid-Open No. 7-336.
No. 18 is known.

FIG. 7 is an exploded perspective view of a conventional piezoelectric vibrating component, in which a piezoelectric element having a circular vibrating electrode 2 formed partially on both opposing surfaces of a piezoelectric substrate 1 and a piezoelectric element of the piezoelectric element. The space 5 on which the adhesive 6 is not applied is formed of a sealing substrate 4 on a flat plate which is joined to both opposing surfaces and an adhesive 6 which joins the sealing substrate 4 and the piezoelectric element.
Similarly, it has a circular shape.

[0004]

In this type of piezoelectric vibrating component, a structure is required that secures vibration (main vibration) at a required frequency and suppresses vibration other than the required frequency. The space for securing the vibration has the same shape (in this case, a circle) corresponding to the conventional vibrating electrode 2 (that is, corresponding to the state of vibration) and sufficiently attenuates so as not to alienate the vibration of the main vibration. The area was secured. However, in this case, the main vibration is not alienated, and at the same time, other unnecessary vibrations are not alienated and are excited in the same manner as the main vibration, so that the characteristic degradation due to the unnecessary vibration occurs. Conversely, if the adhesive portion is formed up to the vicinity of the vibrating electrode to a region where unnecessary vibration can be suppressed, main vibration is also suppressed, and stable characteristics cannot be secured. Further, unlike the unnecessary vibration described above (in this case, a circular vibration shape similar to the main vibration), when an unnecessary vibration having a vibration shape different from the main vibration is generated, if the unnecessary vibration has the same shape as the vibration electrode, Unnecessary vibration cannot be sufficiently suppressed, and it is necessary to have a space shape corresponding to the vibration shape of the unnecessary vibration. Therefore, an object of the present invention is to provide a piezoelectric vibrating component having stable characteristics capable of securing vibration at a required frequency and suppressing unnecessary vibration that adversely affects characteristics.

[0005]

In order to achieve this object, a piezoelectric vibrating component according to the present invention comprises a piezoelectric substrate having vibrating electrodes provided on both front and rear surfaces thereof, a front surface of the piezoelectric substrate, A sealing substrate bonded to the back surface via an adhesive layer was provided, and a space larger than the vibration electrode and having irregularities on the outer periphery was formed between the vibration electrode on the piezoelectric substrate and the sealing substrate. And the above object can be achieved.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention is directed to a piezoelectric substrate having vibrating electrodes provided on both front and rear surfaces thereof, and an adhesive layer on both front and rear surfaces of the piezoelectric substrate. And a sealing substrate joined via a piezoelectric vibrating component having a space between the vibrating electrode on the piezoelectric substrate and the encapsulating substrate and having a space larger than the vibrating electrode and having irregularities on the outer periphery, It has the effect of suppressing unnecessary vibration.

According to a second aspect of the present invention, there is provided the piezoelectric vibration component according to the first aspect, wherein the space has a shape symmetrical with respect to an axis in an arbitrary direction of the piezoelectric substrate. It has an effect of suppressing unnecessary vibration generated symmetrically in the direction.

According to a third aspect of the present invention, there is provided the piezoelectric vibrating component according to the first aspect, wherein the spatial shape is symmetrical with respect to the width direction of the piezoelectric substrate. It has the effect of suppressing the generated unnecessary vibration.

According to a fourth aspect of the present invention, there is provided the piezoelectric vibrating component according to the first aspect, wherein the spatial shape is a shape symmetrical with respect to the length direction of the piezoelectric substrate. It has the effect of suppressing unnecessary vibrations that have been generated.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. Embodiment 1 FIG. 1 is an exploded perspective view of a piezoelectric vibrating component according to the present embodiment. A vibrating electrode 2 is formed on both front and back surfaces of the piezoelectric substrate 1 so as to face each other with the piezoelectric substrate 1 interposed therebetween, and an extraction electrode 3 to the outside is electrically connected to the vibrating electrode 2 and provided at an opposite end. Is provided. A sealing substrate 4 for sealing the vibrating electrodes 2 on the front and back surfaces of the piezoelectric substrate 1
The adhesive layer 6 has a space 5 having a shape different from that of the vibrating electrode 2 (circular in this embodiment) on the surface on the side of the piezoelectric substrate 1.
To form The space 5 is provided between a predetermined portion of the piezoelectric substrate 1 including the vibration electrode 2 and the sealing substrate 4. FIG. 5 is a state diagram of the vibration of the piezoelectric vibrating component in which the vibrating electrode 2 is circular, and the main vibration is attenuated on the concentric circle of the vibrating electrode 2 (7 in FIG. 5). On the other hand, it is known that various kinds of unnecessary vibrations are generated depending on the excitation state of the vibrations in the piezoelectric substrate 1 and the vibration electrode 2, and the unnecessary vibrations affect the characteristics.
As an example, in the case of a vibrating element utilizing tertiary thickness longitudinal vibration, for example, a 20 MHz oscillator, primary thickness longitudinal vibration (generally called fundamental wave vibration) exists as unnecessary vibration. If the vibration is not suppressed, the oscillation does not occur at 20 MHz, but oscillates at the frequency of the fundamental wave, and the desired characteristics may not be secured. FIG.
Shows an example of the attenuation state of the fundamental wave (8 in FIG. 6). In this case, as in the case of the main vibration, the vibration exists concentrically and vibrates up to the vicinity of the vibrating electrode 2. Therefore, it is more effective to provide the adhesive layer 6 as close to the vibrating electrode 2 as possible.
However, if the adhesive layer 6 is provided in the vicinity of the vibrating electrode 2 in the shape of a concentric circle having the same shape as the vibrating electrode 2 as in the related art, the main vibration is affected. Therefore, the present invention focuses on the fact that the fundamental wave has a large vibration change with respect to the main vibration, and surrounds the vibrating electrode 2 as shown in FIG. The space 5 is formed unevenly so as to provide a portion where the distance between the substrate and the adhesive layer 6 is short or long. A portion where the distance between the vibrating electrode 2 and the adhesive layer 6 is long helps attenuation of the main vibration, and a portion where the distance between the vibrating electrode 2 and the adhesive layer 6 is short (the adhesive layer 6 is present near the vibrating electrode 2). Part) can suppress the vibration of the fundamental wave.

In other words, the piezoelectric vibrating component of the present invention allows the space 5 having a shape that has no effect on the attenuation of the main vibration and has an effect of suppressing the unnecessary vibration to be formed by the generation state of the unnecessary vibration typified by the main vibration and the fundamental wave. 6, the characteristic failure caused by the unnecessary vibration is prevented, and the stable characteristic is secured.

Although the distance from the vibrating electrode 2 to the adhesive layer 6 depends on the frequency of the main vibration, it is approximately 20 mm.
The distance is set to be 0 μm to 500 μm. The portion where the distance between the vibration electrode 2 and the adhesive layer 6 is short or long, that is, the state of the unevenness of the space 5 is determined by the excitation state of the unnecessary vibration and the main vibration.

(Embodiment 2) FIG. 2 is an exploded perspective view of a piezoelectric vibrating part according to the present embodiment. The same components as those in FIG. In FIG. 2, a space 5 has an axis in the width direction of the piezoelectric substrate 1 (A-
B), the shape is symmetric with respect to the direction of ± 45 degrees. This corresponds to unnecessary vibration that is forcibly generated in a direction of ± 45 degrees in the width direction. In other words, in the direction of ± 45 degrees, the adhesive layer 6 is formed up to the vicinity of the vibrating electrode 2, and in other parts, a predetermined distance is provided between the vibrating electrode 2 and the adhesive layer 6 in order to help attenuate the main vibration. The distance is secured.

The direction of the angle of the unnecessary vibration generated with respect to the axis in the width direction as described above is such that the adhesive layer
In other parts, a predetermined distance is secured between the vibrating electrode 2 and the adhesive layer 6 to help attenuate the main vibration, and the other parts are symmetric with respect to the direction axis of the angle of the unnecessary vibration. The space 5 is formed as follows.

(Embodiment 3) FIG. 3 is an exploded perspective view of a piezoelectric vibrating component of the present embodiment. The same components as those in FIG. In FIG. 3, the space 5 has a symmetrical shape with respect to the width direction of the piezoelectric substrate 1. This is a shape corresponding to the unnecessary vibration that is forcibly generated in the width direction. In order to suppress the unnecessary vibration in the width direction as in (Embodiment 2), only the width direction extends to the vicinity of the vibrating electrode 2. The adhesive layer 6 is formed, and the other parts are combined with the vibrating electrode 2 and the adhesive layer 6 to help attenuate the main vibration.
And a space 5 is formed so as to be symmetrical with respect to the direction axis of the angle of the unnecessary vibration.

(Embodiment 4) FIG. 4 is an exploded perspective view of a piezoelectric vibrating component of the present embodiment. The same components as those in FIG. 1 are denoted by the same reference numerals and description thereof will be simplified. In FIG. 4, the space 5 has a symmetrical shape with respect to the length direction of the piezoelectric substrate 1. This is a shape corresponding to unnecessary vibration that is forcibly generated in the length direction. Like in the second embodiment, in order to suppress unnecessary vibration in the length direction, only the vibration electrode 2 in the length direction is used. The adhesive layer 6 is formed up to the vicinity, and a predetermined distance is secured between the vibrating electrode 2 and the adhesive layer 6 to help attenuate the main vibration. The space 5 is formed so as to be symmetrical with respect to the direction axis.

(Embodiment 1) to (Embodiment 4)
In the above, the size of the space 5, that is, the distance between the vibration electrode 2 and the adhesive layer 6 is determined by the state of excitation of the main vibration and the unnecessary vibration. The outer periphery of the space 5 is curved, but may be a space surrounded by straight lines. However, when the vibration is observed on a plane, the outer periphery of the space 5 is considered in consideration of a circular or elliptical shape. It is more effective to form a curve, and it is easy to select an effective shape.

[0018]

As described above, according to the present invention, vibration at a required frequency can be ensured, and at the same time, unnecessary vibration that adversely affects the characteristics can be suppressed. Therefore, a piezoelectric vibration component having stable characteristics can be provided. .

[Brief description of the drawings]

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

FIG. 2 is an exploded perspective view of a piezoelectric vibrating component according to a second embodiment of the present invention.

FIG. 3 is an exploded perspective view of a piezoelectric vibrating component according to a third embodiment of the present invention.

FIG. 4 is an exploded perspective view of a piezoelectric vibrating component according to a fourth embodiment of the present invention.

FIG. 5 is an explanatory diagram showing a damped state of main vibration of a general piezoelectric vibration component.

FIG. 6 is an explanatory diagram showing an attenuation state of unnecessary vibration (fundamental wave vibration) of a general piezoelectric vibration part.

FIG. 7 is an exploded perspective view of a conventional piezoelectric vibration component.

[Explanation of symbols]

 Reference Signs List 1 piezoelectric substrate 2 vibrating electrode 4 sealing substrate 5 space 6 adhesive layer

Claims (4)

[Claims] 1. A piezoelectric substrate having a vibrating electrode provided on both front and back surfaces thereof, and a sealing substrate bonded to both front and back surfaces of the piezoelectric substrate via an adhesive layer, A piezoelectric vibrating component in which a space that is larger than the vibrating electrode and that has irregularities on the outer periphery is formed between the vibrating electrode on the piezoelectric substrate and the sealing substrate. 2. The piezoelectric vibrating component according to claim 1, wherein the space has a shape symmetric with respect to an axis of the piezoelectric substrate in an arbitrary direction. 3. The piezoelectric vibration component according to claim 1, wherein the space has a shape symmetric with respect to a width direction of the piezoelectric substrate. 4. The piezoelectric vibration component according to claim 1, wherein the space has a shape symmetric with respect to a length direction of the piezoelectric substrate.