JPH0613835A - Chip type piezoelectric resonator - Google Patents

Abstract

PURPOSE:To improve the connecting reliability between a resonator element and an external electrode by forming a lead-out electrode in a belt-shaped range covering the end face of the resonator element through the middle position between the inner surface of a recessed part of a holding plate and the tip of the electrode extending from the other end side of the resonator element. CONSTITUTION:The width W of each of lead-out electrodes 13 and 14 is set larger than the distance W1 covering one of both ends of a resonator element 1 through the inner surfaces of the recessed parts 5a and 6a of the holding plates 5 and 6. At the same time, the width W is set smaller than the distance W2 covering one of both ends of the element 1 through the tips of electrodes 3 and 4 extending from the other end of the element 1. In other words, W1<W<W2 is satisfied. Thus, the width W is set and therefore, the side parts of the areas of both electrode 3 and 4 that are disconnected most easily can be connected by the electrodes 13 and 14. Even if the disconnection 3a occurs at a part near the adhering part of both electrodes 3 and 4, for example, the electrodes 3 and 4 can be surely connected to the external electrodes via the electrode 13 and 24.

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 resonator, and more particularly to a thin chip type piezoelectric resonator that can be used in thin electronic devices.

[0002]

2. Description of the Related Art Conventionally, as a chip type piezoelectric resonator, as shown in FIG.
The one shown in FIG. 2 is known. This piezoelectric resonator includes an energy trap type thickness shear vibration mode resonator element 1, holding plates 5 and 6, and sealing plates 7 and 8. The resonator element 1 is provided with a piezoelectric substrate 2 made of a rectangular thin piezoelectric ceramic plate, and the piezoelectric substrate 2 is polarized in its longitudinal direction. One electrode 3 is formed from one end side of the front surface of the piezoelectric substrate 2 to a region of approximately ⅔ of the total length, and the other electrode 4 is formed from the other end side of the back surface of the piezoelectric substrate 2 to a region of approximately ⅔ of the total length. Has been formed. The holding plates 5 and 6 are made of a high-strength material such as alumina ceramics, and have the same thickness and the same length as the piezoelectric substrate 2. The holding plates 5 and 6 are electrodes 3 of the resonator element 1.
Concave portions 5a and 6a for securing a vibration space are formed on the opposite surfaces of the resonator element 1 which are bonded to both side surfaces forming the groove 4. The sealing plates 7 and 8 are also made of the same material as that of the holding plates 5 and 6, and are bonded to the upper and lower surfaces of the resonator element 1 and the holding plates 5 and 6 that are bonded and integrated to seal the inside. . The electrodes 3 and 4 of the resonator element 1 are provided on the end face from which the electrodes 3 and 4 are drawn out and on the upper and lower faces of both ends adjacent to the end face.
The external electrodes 9 and 10 which are electrically connected to the respective electrodes are formed by means such as vapor deposition.

In the case of the above chip type piezoelectric resonator, since the surface areas of the electrodes 3 and 4 of the resonator element 1 exposed on the end face side are equal to the thickness thereof, the electrodes 3 and 4 and the external electrodes 9 and 1 are formed.
There is a problem that the contact area with 0 is very small, the connection is insufficient, the wire is easily broken, and the reliability is low.

Therefore, as shown in FIGS. 3 and 4, the resonator element 1
It is proposed that the lead electrodes 11 and 12 for connecting the electrodes 3 and 4 of the resonator element 1 and the external electrodes 9 and 10 are formed in a strip shape on the upper surface of the bonding plate and the holding plates 5 and 6 which are bonded to each other. Has been done. In this case, in addition to the end faces of the electrodes 3 and 4, the external electrodes 9 and
Since it is electrically connected to 10, reliability can be improved.

[0005]

However, even if the extraction electrodes 11 and 12 are provided as described above, if the disconnection 3a (see FIG. 4) occurs in the vicinity of the bonded portion of the electrodes 3 and 4, the electrodes 3 and 4 are connected to each other. In some cases, the external electrodes 9 and 10 were not surely conducted. It is considered that the disconnection 3a is generated in the vicinity of the bonded portions of the electrodes 3 and 4 because the stress when the holding plates 5 and 6 are bonded is applied to the electrodes 3 and 4. Therefore, the purpose of the present invention is to
An object of the present invention is to provide a chip-type piezoelectric resonator capable of improving the connection reliability between the electrodes of the resonator element and the external electrodes without changing the structures of the resonator element and the holding plate.

[0006]

In order to achieve the above object, according to the present invention, an electrode extending from one end of one side surface of a piezoelectric substrate and an electrode extending from the other end of the other side surface are partially opposed to each other. A resonator element formed as described above, a holding plate bonded to both side surfaces provided with electrodes of the resonator element, and provided with a recess for forming a vibration space on a surface facing the resonator element, and the resonator element and A sealing plate adhered to both upper and lower surfaces of the holding plate, and formed on at least the end face side of the resonator element of the sealing plate,
In a chip-type piezoelectric resonator including an electrode of a resonator element and an external electrode electrically connected to the resonator element, an electrode of the resonator element is provided on at least one of the upper surface and the lower surface of both ends of the resonator element and the holding plate bonded to each other. The extraction electrode for connecting the external electrode and the external electrode is formed in a strip shape, and the width of the extraction electrode is defined by the end surface of the resonator element and the tip of the electrode extending from the inner surface of the recess of the holding plate and the opposite side of the resonator element. It is characterized in that the range is set to the intermediate position of.

The extraction electrode is formed in a band shape in a range from one end of the resonator element to an intermediate position between the inner surface of the concave portion of the holding plate and the tip of the electrode extending from the opposite side of the resonator element. In other words, the extraction electrode is formed. By forming a wide portion so as to cover the portion where the wire breakage is likely to occur, even if the wire breakage occurs near the bonded portion of the electrode of the resonator element, it is possible to surely conduct electricity to the external electrode through the extraction electrode. The reason for setting the width of the extraction electrode in the range from one end of the resonator element to the intermediate position between the inner surface of the recess of the holding plate and the tip of the electrode extending from the side opposite to the resonator element is This is because if the width is narrower than the side surface, electrical continuity cannot be measured if a wire breakage occurs near the bonded part of the electrode.On the other hand, if the extraction electrode is widened to the tip position of the electrode extending from the opposite side of the resonator element, resonance will occur. This is because both electrodes of the child element become conductive.

[0008]

FIG. 5 and FIG. 6 show an example of a chip type piezoelectric resonator according to the present invention. The same parts as those of the conventional example (FIGS. 1 to 4) are designated by the same reference numerals and their description is omitted. 5 and 6
The sealing plates 7 and 8 are omitted.

The piezoelectric resonator of the present invention is characterized in that the width of the lead-out electrodes 13 and 14 formed in a strip shape for connecting the electrodes 3 and 4 of the resonator element 1 and the external electrodes 9 and 10 is such that This is a point in the range from one end of the element 1 to an intermediate position between the inner side surfaces of the concave portions 5a, 6a of the holding plates 5, 6 and the tips of the electrodes 3, 4 extending from the other end side of the resonator element 1. That is, in FIG. 6, the width dimension W of the extraction electrodes 13 and 14 is wider than the distance W ₁ from one end of the resonator element 1 to the inner side surfaces of the recesses 5a and 6a of the holding plates 5 and 6, and It is shorter than the distance W ₂ from one end to the tips of the electrodes 3 and 4 extending from the other end of the resonator element 1. This can be expressed as follows.

[0010]

[Equation 1] W ₁ <W <W ₂

By setting the width W of the extraction electrodes 13 and 14 in this manner, the side portions of the electrodes 3 and 4 where the wire breakage is most likely can be connected by the extraction electrodes 13 and 14, even if the electrodes 3 and 4 are connected. Even if the disconnection 3a occurs in the vicinity of the bonded portion, it can be surely conducted to the external electrodes 9 and 10 via the extraction electrodes 13 and 14.

The lead electrodes 13 and 14 are formed by a known method such as vapor deposition after the resonator element 1 and the holding plates 5 and 6 are bonded. That is, the resonator element 1 and the holding plate 5,
The mask is placed on 6 and the extraction electrodes 13 and 14 are formed by adhering the metal particles to predetermined positions on the upper surface. At this time, a part of the metal particles also wraps around inside the recesses 5a and 6a. As shown in FIG. 6, an electrode portion 13a that is electrically connected to the extraction electrodes 13 and 14 may be formed. In this case, the electrode portion 13a covers the disconnection portion 3a and the conductive path from the electrodes 3 and 4 to the external electrodes 9 and 10 is widened, so that there is an advantage that the connection reliability is further improved.

[0013]

As is apparent from the above description, according to the present invention, the extraction electrode is provided with the end face of the resonator element, the inner surface of the recess of the holding plate, and the tip of the electrode extending from the other end side of the resonator element. Since it is formed in a band shape in the range up to the intermediate position, the extraction electrode can cover the portion of the resonator element electrode where the electrode is easily broken, and the connection reliability between the resonator element electrode and the external electrode can be improved. . Further, since it is not necessary to change the structure of the resonator element or the holding plate only by changing the width of the extraction electrode, the manufacturing cost does not increase.

[Brief description of drawings]

FIG. 1 is a perspective view of an example of a chip-type piezoelectric resonator according to the present invention.

FIG. 2 is an exploded perspective view of the piezoelectric resonator shown in FIG.

FIG. 3 is a perspective view of a resonator element and a holding plate in the piezoelectric resonator of FIG.

FIG. 4 is an enlarged perspective view of a part of FIG.

FIG. 5 is a perspective view of a resonator element and a holding plate of the piezoelectric resonator according to the present invention.

FIG. 6 is an enlarged perspective view of a part of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Resonator element 2 Piezoelectric substrate 3,4 Electrode 3a Disconnection part 5,6 Holding plate 7,8 Sealing plate 9,10 External electrode 13,14 Extraction electrode

Claims (1)

[Claims] 1. A resonator element in which an electrode extending from one end of one side of a piezoelectric substrate and an electrode extending from the other end of the other side of the piezoelectric substrate are partially opposed to each other, and an electrode of the resonator element. A holding plate bonded to both side surfaces provided with a concave portion for forming a vibration space on a surface facing the resonator element, and sealing plates bonded to both upper and lower surfaces of the resonator element and the holding plate, In a chip-type piezoelectric resonator that is formed on at least the end face side of the resonator element of the sealing plate and includes an external electrode that is electrically connected to the electrode of the resonator element, both ends of the resonator element and the holding plate bonded to each other Lead-out electrodes for connecting the electrodes of the resonator element and the external electrodes are formed in strips on at least one of the upper and lower surfaces of the portion,
The width of the extraction electrode is set in the range from the end face of the resonator element to the intermediate position between the inner surface of the recess of the holding plate and the tip of the electrode extending from the opposite side of the resonator element. Type piezoelectric resonator.