JPH0350877A - Piezoelectric component - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to piezoelectric components used in filter circuits, trap circuits, frequency demodulation circuits, etc. in various electronic circuits.

(Prior Art) With recent technological advances, not only capacitors and resistors, but also coil parts and mechanical parts are becoming smaller.

This trend of miniaturization of electronic components is no exception for piezoelectric components such as piezoelectric resonators and piezoelectric filters.

An exploded perspective view, an external perspective view, and a vertical sectional view of a conventional chip-shaped piezoelectric component, which is an example of a piezoelectric component, are shown in FIGS. 3, 4, and 5, respectively.

The above chip pressure! The component is a chip of a piezoelectric resonator that utilizes the energy-trapped thickness longitudinal vibration of a ceramic piezoelectric substrate 1, and includes an element 2 of the piezoelectric resonator constituted by the piezoelectric substrate 1, and the above-mentioned components of this element 2. A first cover member 3 and a second cover member 4 are bonded to one main surface and the other main surface of the piezoelectric substrate l, respectively, and are formed on the end surfaces of the element 2 and the cover members 3 and 4. A first external terminal electrode 5 and a second external terminal electrode 6 are provided.

The element 2 has one vibrating electrode 7 and the other vibrating electrode 8 of a resonator formed at the center of one main surface and the other main surface of a ceramic piezoelectric substrate l, respectively. The one vibrating electrode 7 has an extraction electrode 9
It is drawn out to an extraction terminal lO formed on one side of one main surface of the piezoelectric substrate l. Further, the other vibrating electrode 8 is led out by a lead-out electrode 11 to a lead-out terminal 12 formed on one side of the other main surface of the piezoelectric substrate 1 . The lead terminals 10, 12 are located on opposite sides of the center of the piezoelectric substrate l. In the piezoelectric substrate 1, its vibrating electrodes 7° and the vicinity thereof perform energy-trapped thickness vibration.

On the other hand, the first cover member 3 and the second cover member 4 are both made of an insulating material, and serve as exterior members for the chip-shaped piezoelectric component. As shown in Figure 3, the first
The cover member 3 is adhered to one main surface of the piezoelectric substrate 1 of the element 2 by a resin 13 applied to one main surface of the piezoelectric substrate 1.

Further, the second cover member 4 also includes the resin 1 applied to the other main surface of the piezoelectric substrate l of the element 2 in the same manner as described above.
4, it is bonded to the other main surface of the piezoelectric substrate 1.

The thickness of the resin 13 forms a gap gI between the vibrating electrode 7 on the piezoelectric substrate l and the cover member 3, and the thickness of the resin 14 forms a gap g2 between the vibrating electrode 8 on the piezoelectric substrate l. is formed.

The first external terminal electrode 5 is the lead-out electrode I.
A lead electrode is formed by applying solder on a metal thin film Sp formed by sputtering on one end face side of the element 2 and cover member 3.4 which are bonded to one side where O is formed. electrically connected to lO. Further, the second external terminal electrode 6 is formed by sputtering on one end surface side of the element 2 and the cover member 3.4, which are bonded to one side on which the extraction electrode 12 is formed. metal thin film S
It is formed by applying solder on p, and is electrically connected to the extraction electrode 12.

(Problem to be Solved by the Invention) In the conventional energy trapping type chip-shaped piezoelectric component having the above-mentioned configuration, the resin 13°14 has a kind of damping effect and suppresses vibrations, so the vibration electrode and It is necessary to form a predetermined vibration space between them, and furthermore, it is necessary to apply resin to a predetermined width or more around the element 2 to ensure adhesiveness and sealing properties.

Conventionally, in the resin application pattern, an inner peripheral contour similar to the contour of the vibrating electrode has been formed so that the distance from the vibrating electrode is constant. As described above, in the past, it was necessary to maintain a certain gap between the vibrating electrode and the vibrating electrode, and this gap defined the limit of miniaturization of chip-shaped piezoelectric components.

In addition, since the hardness and elastic dust during curing differ depending on the type of resin, by selecting a resin with a low degree of vibration suppression, vibration suppression can be alleviated, and the above-mentioned gap can be made smaller, making piezoelectric parts more compact. Although it is theoretically possible to do so, for example, when silicone resin is used, there is almost no damping effect, so the vibrating part becomes too free, creating new problems such as spurious noise. occurs in

As piezoelectric components become smaller, it becomes more difficult to control the characteristics of piezoelectric components based on the relationship between the type of resin and the size of the gap, and the variation in products becomes larger.

SUMMARY OF THE INVENTION An object of the present invention is to provide a piezoelectric component that solves the above problems, can be easily miniaturized, and can prevent the occurrence of solar radiation.

(Means for Solving the Problems) Therefore, the present invention provides an element in which a vibrating electrode is formed on a piezoelectric substrate and the piezoelectric substrate performs energy-confined vibration in the vibrating electrode portion, and a vibration space of the vibrating portion of this element. and an exterior member that covers at least one and the other main surface of the element, and the piezoelectric component has the vibrating electrode pulled out to the outside of the exterior member,
A damping layer having a pattern for damping spurious vibrations of energy trap type vibrations of the element is present between the piezoelectric substrate of the element and the exterior member.

Another feature of the present invention is that the damping layer is an adhesive that adheres the element and the exterior member to each other.

Furthermore, another feature of the present invention is that the damping layer is a sealant that seals the vibration space between the element and the exterior member.

Furthermore, a further feature is that a portion of the damping layer is located on the element within the vibration space.

(Examples) Examples according to the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is an exploded perspective view of an embodiment of a chip-shaped piezoelectric component to which the present invention is applied. The basic configuration is shown in Figure 3~
Since it is similar to the conventional chip-shaped piezoelectric component shown in FIG. 5, detailed explanation will be omitted.

Note that although the resin has functions as an adhesive, a sealant, and a damping agent at the same time, in this embodiment, the function as a damping agent will be mainly explained.

The present invention is characterized in that it effectively obtains an appropriate amount of damping in the piezoelectric substrate by varying the resin coating pattern in accordance with the required characteristics of the piezoelectric component. An example of the application pattern of the resin as a damping agent will be explained, but it is also possible to use another resin for adhesion and apply it in a different application pattern, or it is possible to apply the damping agent and the adhesive using one type of resin. It may be used for both purposes.

FIGS. 2(a) to (f) show top views of the element 2,
FIG. 2(g) shows a longitudinal sectional view of the element 2.

FIG. 2(a) shows a coating pattern of the resin 13 of the element 2 also shown in FIG. This coating pattern is set such that the distance between the vibrating electrode 7 increases in the diagonal direction, and forms a necessary vibration space S for the vibrating electrode 7. In this way, by providing a large gap in a certain direction, it becomes possible for the resin 13 to come close enough to contact the vibrating electrode 7 in a certain direction, which impairs the adhesion and sealing properties with the cover member. Without a doubt,
Appropriate damping is provided and spurious noise is also prevented. In this case, the front side of the vibrating electrode 7 is in contact with the resin 13.

FIG. 2(b) shows a coating pattern of the resin 13 in which gaps are provided radially around the vibrating electrode 7. In this example as well, instead of having a large gap in a certain direction, it is possible to almost eliminate the gap in a certain direction, thereby ensuring adhesiveness and sealing properties and obtaining an appropriate amount of damping. In addition, Fig. 2(b)
Although the distance and length between the convex portion and the concave portion of the resin are constant, the present invention is not limited thereto. Further, the convex portion of the resin may overlap the vibrating electrode 7 in some cases.

FIG. 2(c) shows a resin pattern in which gaps are provided in front and behind the vibrating electrode 7 (on the left and right sides in the figure).

Again, the right and left sides (top and bottom in the diagram)
In this case, the resin 13 may be applied to the vibrating electrode 7.

In FIG. 2(d), a large gap is provided diagonally in front of the vibrating electrode 7 in the left and right directions, and a gap in the diagonally rear direction in the left and right directions, and a small gap is provided in the front of the vibrating electrode 7 as a vibrating part.

FIG. 2(e) shows a pattern in which a rectangular gap is provided around the vibrating electrode 7, and resin is applied in spots within this rectangular gap. This circular portion 13a is used for load adjustment to correct product variations during firing of the piezoelectric substrate 1.

Therefore, the number, shape, and position are arbitrary.

FIG. 2Cf) is an example of a resin pattern in which rectangular vibrating electrodes 7 are arranged obliquely. arrangement of the vibrating electrode 7;
The resin pattern can be varied depending on the shape and the like.

FIG. 2(g) is a longitudinal cross-sectional view of the element 2 coated with resin 13, 14. In this case, the above figure 2(a)
The damping amount is adjusted by partially changing the thickness of the resin, as shown in the figure, instead of changing the planar resin application pattern as shown in (f).

In all of the above embodiments, chip-shaped piezoelectric components have been described, but the present invention is not limited to this. It can also be applied to parts.

(Effects) According to the present invention, since the damping layer exists between the piezoelectric substrate of the element and the exterior member, an appropriate amount of damping can be applied depending on the characteristics, size, etc. of the piezoelectric component. This solves the problems of resin selection and spurious generation associated with miniaturization of conventional piezoelectric components, making it possible to further miniaturize piezoelectric components.

Further, when the damping layer is an adhesive, the damping layer can damp spurious vibrations of the vibrating portion of the element and bond the exterior member to the element.

Furthermore, when the damping layer is a sealant, the vibration space can be sealed between the element and the exterior member by the damping layer.

Furthermore, by locating part of the damping layer on the element within the vibration space, spurious vibrations that need to be removed can be removed more easily.

[Brief explanation of drawings]

FIG. 1 is an exploded perspective view of an embodiment of a chip-shaped piezoelectric component according to an embodiment of the present invention. FIGS. 2(a) to 2(f) are top views of elements showing resin coating patterns of chip-shaped piezoelectric components according to embodiments of the present invention, respectively. FIG. 2(g) is a longitudinal sectional view of an element showing a resin coating pattern of a chip-shaped piezoelectric component according to an embodiment of the present invention. FIG. 3 is an exploded perspective view of a conventional chip-shaped piezoelectric component. FIG. 4 is an external perspective view of a conventional chip-shaped piezoelectric component. FIG. 5 is a longitudinal cross-sectional view of a conventional chip-shaped piezoelectric component. l...piezoelectric substrate, 2...element, 3...first
Cover member, 4...Second cover member, 5.6...
・External terminal, 7.8... Vibration terminal, 9.11... Extracting electrode, 10.12... Extracting terminal, 13.14...
resin.

Claims (4)

[Claims] (1) An element in which a vibrating electrode is formed on a piezoelectric substrate and the piezoelectric substrate performs energy-trapped vibration in the vibrating electrode portion, and a vibration space for the vibrating portion of this element, and at least one of the above elements and the other main body. In a piezoelectric component comprising an exterior member that covers a surface of the piezoelectric element, and in which the vibrating electrode is pulled out to the outside of the exterior member, there is a space between the piezoelectric substrate of the element and the exterior member that generates spurious vibrations of energy-trapped vibrations of the element. A piezoelectric component characterized in that a damping layer having a pattern for damping is present. (2) The piezoelectric component according to claim 1, wherein the damping layer is an adhesive that adheres the element and the exterior member to each other. (3) The piezoelectric component according to claim 1, wherein the damping layer is a sealant that seals the vibration space between the element and the exterior member. (4) The piezoelectric component according to claim 1, wherein a portion of the damping layer is located on the element within the vibration space.