JPH06216693A - Piezoelectric resonance component - Google Patents

Abstract

PURPOSE:To improve reliability by reducing stress applied to a piezoelectric element when mechanical stress is applied to a mounted substrate and suppressing and preventing the damage of the piezoelectric element and the deviation of a resonance frequency. CONSTITUTION:In a piezoelectric resonance component A provided with the piezoelectric element 4, holding substrates 6 adhered to both side faces of the piezoelectric element 4 by adhesive 8 for holding the piezoelectric element 4 so as to enable vibration and sealing substrates 7 for sealing by holding the piezoelectric element 4 and the holding substrates 6 there between from both upper and lower main surface sides, the thickness of the adhesive (layer) 8 for adhering the holding substrates 6 to both side faces of the pizoelectric element 4 is defined as >=100mum.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piezoelectric resonance component, and more particularly to a piezoelectric resonance component which has improved strength against external stress such as bending of a mounting substrate.

[0002]

2. Description of the Related Art In recent years, as electronic devices and electric devices have been miniaturized, there has been an increasing demand for miniaturization of piezoelectric resonance components used therein. FIG. 5 is an exploded perspective view showing an example of a thin piezoelectric resonance component utilizing a thickness shear vibration mode developed to meet such a demand.

In this piezoelectric resonance component B, as shown in FIG. 5, vibrating electrodes 22 are arranged on the longitudinal side surfaces of the piezoelectric substrate 21 that face each other, and each vibrating electrode 22 is connected to the piezoelectric substrate 21. Extraction electrode 23 at the end on the different side
The piezoelectric element 24 of the thickness-shear vibration mode formed by pulling out is used.

The vibrating electrode 22 of the piezoelectric element 24
The vibrating electrodes 22 of the piezoelectric element 24 are provided on both side surfaces on which the
A holding substrate 26 made of an insulating material in which a concave portion 25 is formed to secure a vibration space between the surface of the piezoelectric element 24 and the surface on which the piezoelectric element 24 is vibrated by the holding substrate 26. Held possible. In the conventional piezoelectric resonance component, the thickness of the adhesive (layer) 28 is usually about several μm.

Further, the piezoelectric element 24 and the holding substrate 26
Is sealed by adhering a sealing substrate 27 made of an insulating material such as resin from above and below both main surfaces with an adhesive 30. Since the adhesive 30 also functions as a spacer and forms a gap between the piezoelectric element 24 and the sealing substrate 27, the sealing substrate 27 does not hinder the vibration of the piezoelectric element 24. In addition, external electrodes 29 that are electrically connected to the extraction electrodes 23 are formed on both end surfaces of the laminated body obtained by sealing the piezoelectric element 24 and the holding substrate 26 with the sealing substrate 27.

[0006]

However, in the above-mentioned conventional piezoelectric resonance component B, as shown in FIG. 3, when the piezoelectric resonance component B is mounted on the mounting substrate 31, the mounting substrate 31 is indicated by the arrow X. When stress is applied in the direction as shown, the piezoelectric resonance component B is transformed into a fan shape. And
As the piezoelectric resonance component B is deformed, the piezoelectric element 24 constituting the piezoelectric resonance component B is deformed by the stress as shown in FIG. There is a problem of damage.

As described above, in the above-described conventional piezoelectric resonance component B, when the mounting substrate is deformed, stress is likely to be applied to the piezoelectric element 24, and the characteristics may be varied or the piezoelectric element 24 may be damaged. However, the reality is that it is not always reliable.

Note that FIGS. 3 and 6 schematically show the state of deformation of the piezoelectric resonance component B, and the degree of deformation is shown largely for ease of understanding. ,
The piezoelectric resonance component B does not deform so much as shown in FIGS.

The present invention solves the above-mentioned problems, and when mechanical stress is applied to the mounting board,
An object of the present invention is to provide a highly reliable piezoelectric resonance component capable of preventing deterioration of characteristics such as shift of resonance frequency and damage of piezoelectric element without applying excessive stress to the piezoelectric element. .

[0010]

In order to achieve the above object, in a piezoelectric resonance component of the present invention, vibrating electrodes are provided on surfaces of a piezoelectric substrate that face each other, and the piezoelectric substrate is different from each vibrating electrode. A piezoelectric element in a thickness-shear vibration mode in which a lead-out electrode is drawn out to an end portion on the side, a holding substrate that is adhered to both side surfaces of the piezoelectric element with an adhesive to vibratably hold the piezoelectric element, the piezoelectric element, and A piezoelectric resonance component comprising a holding substrate that holds and holds the holding substrate from both upper and lower main surfaces thereof, wherein the adhesive (layer) adheres the holding substrate to both side surfaces of the piezoelectric element.
Is 100 μm or more in thickness.

[0011]

Since the thickness of the adhesive (layer) for adhering the holding substrate to both sides of the piezoelectric element is 100 μm or more, stress is applied to the mounting substrate and the piezoelectric resonance component is deformed to hold the piezoelectric element. Even when the holding substrate is deformed, the adhesive absorbs the stress caused by the deformation and prevents excessive stress from being applied to the piezoelectric element, which deteriorates the characteristics such as the resonance frequency shift and damages the piezoelectric element. It becomes possible to prevent such.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an exploded perspective view showing a piezoelectric resonance component according to an embodiment of the present invention, and FIG. 2 shows a state in which a piezoelectric element is vibrably held by attaching a holding substrate to both side surfaces of the piezoelectric element. It is a top view shown.

As shown in FIGS. 1 and 2, in the piezoelectric resonance component A of this embodiment, the piezoelectric substrate (PZT substrate) 1
Of the thickness-shear vibration mode, which are formed by arranging the vibrating electrodes 2 on the longitudinal side surfaces facing each other and pulling out the extraction electrodes 3 from the respective vibrating electrodes 2 to the ends on the different sides of the piezoelectric substrate 1. 4 is used.

Further, on both side surfaces of the piezoelectric element 4 on which the vibrating electrode 2 is arranged, a concave portion 5 for securing a vibrating space with the surface of the piezoelectric element 4 on which the vibrating electrode 2 is arranged. A holding substrate 6 made of an insulator in which is formed,
The piezoelectric element 4 is vibratably held by the holding substrate 6. The holding substrate 6 is adhered to the piezoelectric element 4 by an adhesive 8 having a greater flexibility than the piezoelectric substrate 1 and the holding substrate 6 (for example, an epoxy resin-based or silicone resin-based adhesive) 8. The thickness T (FIG. 2) of the (layer) 8 is adjusted to be about 300 μm.

Further, the piezoelectric element 4 and the holding substrate 6 are sealed by adhering the sealing substrate 7 with the adhesive 10 from both upper and lower main surface sides thereof. Since the adhesive 10 also functions as a spacer and forms a gap between the piezoelectric element 4 and the sealing substrate 7, the sealing substrate 7 does not hinder the vibration of the piezoelectric element 4.

External electrodes 9 that are electrically connected to the extraction electrodes 3 are formed on both end surfaces of the laminated body obtained by sealing the piezoelectric element 4 and the holding substrate 6 with the sealing substrate 7.

In the piezoelectric resonance component A of this embodiment,
As described above, the holding substrate 6 is adhered to both side surfaces of the piezoelectric element 4 on which the vibrating electrode 2 is arranged, by the adhesive 8 having greater flexibility than the piezoelectric substrate 1 and the holding substrate 6 forming the piezoelectric element 4. And the thickness T (FIG. 2) of the adhesive (layer) 8 is
Since it is significantly thicker than the conventional piezoelectric resonance component of several μm, that is, about 300 μm, stress is applied to the mounting substrate 31 when the piezoelectric resonance component A is mounted on the mounting substrate 31, as shown in FIG. When the holding substrate 6 holding the piezoelectric element 4 of the piezoelectric resonance component A is deformed, the adhesive 8 is deformed to absorb the stress caused by the deformation of the holding substrate 6, as shown in FIG. As a result, excessive stress is prevented from being applied to the piezoelectric element 4, and the mounting substrate 31 (FIG. 3)
It is possible to prevent the deterioration of characteristics such as the shift of the resonance frequency and the damage of the piezoelectric element 4 due to the deformation of the piezoelectric element 4 when the piezoelectric element 4 is deformed.

In the above embodiment, the case where the thickness of the adhesive (layer) is about 300 μm has been described, but if the thickness of the adhesive (layer) is 100 μm or more, a temporary stress absorbing effect can be obtained. If it is 500 μm or more, a larger stress absorption effect can be obtained.
It should be noted that even if the thickness of the adhesive (layer) exceeds 1000 μm, no significant improvement in the stress absorption effect is seen, and the thickness of the piezoelectric resonance component, which is a product, becomes large. The thickness of the agent (layer) is preferably 1000 μm or less.

Further, in the piezoelectric resonance component of the present invention, there is no particular restriction on the kind of the adhesive, and various kinds of adhesives having greater flexibility than the piezoelectric substrate and the holding substrate forming the piezoelectric element after the bonding (after curing) are used. It is possible to use an adhesive.

In the above embodiment, the case where the piezoelectric element having the vibrating electrodes provided on both side surfaces of the piezoelectric substrate is used has been described, but in the present invention, the vibrating electrodes are arranged on the upper surface and the lower surface of the piezoelectric substrate. The present invention can be applied to a piezoelectric resonance component using the provided piezoelectric element, and the same effect can be obtained in that case as well.

Further, the piezoelectric resonance component of the present invention is not limited to the above-mentioned embodiment in other respects, and the shape of the piezoelectric element, the electrode pattern, the constituent members such as the holding substrate and the sealing substrate, etc. With respect to the target shape and the like, various applications and modifications can be made within the scope of the invention.

[0022]

As described above, in the piezoelectric resonance component of the present invention, since the thickness of the adhesive (layer) for adhering the holding substrate to both side surfaces of the piezoelectric element is 100 μm or more, mechanical stress is not applied to the mounting substrate. Even when applied, it is possible to prevent the adhesive from deforming and absorbing the stress caused by the deformation of the piezoelectric resonance component, and thus applying excessive stress to the piezoelectric element.

Therefore, when the mounting substrate is deformed, it is possible to prevent the deterioration of the characteristics such as the shift of the resonance frequency due to the deformation of the piezoelectric element and the damage of the piezoelectric element, so that the reliability can be improved. .

[Brief description of drawings]

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

FIG. 2 is a plan view showing a state in which a holding substrate is bonded to both side surfaces of a piezoelectric element that constitutes a piezoelectric resonance component according to an embodiment of the present invention, and the piezoelectric element is vibratably held.

FIG. 3 is a plan view showing a state in which a mounting board on which a piezoelectric resonance component according to an embodiment of the present invention is mounted is deformed by stress.

FIG. 4 is a plan view schematically showing a deformed state of a piezoelectric element or the like when stress is applied to a piezoelectric resonance component according to an embodiment of the present invention.

FIG. 5 is an exploded perspective view showing a conventional piezoelectric resonance component.

FIG. 6 is a plan view schematically showing a deformed state of a piezoelectric element or the like when stress is applied to a conventional piezoelectric resonance component.

[Explanation of symbols]

 A Piezoelectric resonance component 1 Piezoelectric substrate 2 Vibration electrode 3 Extraction electrode 4 Piezoelectric element 5 Recessed portion 6 Holding substrate 7 Sealing substrate 8 Adhesive 9 External electrode 31 Mounting substrate

Claims (1)

[Claims] 1. A thickness-shear vibration mode piezoelectric element in which vibrating electrodes are provided on mutually opposing surfaces of a piezoelectric substrate, and lead-out electrodes are drawn from the respective vibrating electrodes to end portions on different sides of the piezoelectric substrate. A holding substrate that is adhered to both side surfaces of the piezoelectric element with an adhesive to hold the piezoelectric element in a vibrating manner, and a sealing substrate that holds the piezoelectric element and the holding substrate from both upper and lower main surface sides to seal them. A piezoelectric resonance component comprising: a piezoelectric resonance component, wherein the thickness of the adhesive (layer) for adhering the holding substrate to both side surfaces of the piezoelectric element is 100 μm or more.