JPH088678A - Piezoelectric vibrator - Google Patents

Abstract

(57) [Abstract] [Purpose] The objective is to reduce the size of piezoelectric vibrators used in microcomputers and the like. [Structure] A piezoelectric vibrating element 3 is provided inside a case 1 having a U-shaped cross section, and the piezoelectric vibrating element 3 is bonded and fixed to a metal plate 6 in a side opening of the case 1 by using a conductive adhesive 5. .

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piezoelectric vibrator utilizing the vibration of a piezoelectric element.

[0002]

2. Description of the Related Art In recent years, piezoelectric vibrators are products that are expected to develop in the future as electronic components indispensable for clock oscillation for microcomputers, oscillation of various remote control devices, and the like.

An example of a conventional piezoelectric vibrator will be described below. FIG. 7 is an external perspective view of a conventional piezoelectric vibrator, FIG. 8 is an enlarged cross-sectional view of a main part thereof, and FIG. 9 is an equivalent circuit diagram thereof. Note that FIG. 8 shows only the left half because it is bilaterally symmetric. A first electrode 13a, a second electrode 13b, and a third electrode 13c are provided on the front and back surfaces of the insulating substrate 12 at regular intervals, and the first to third electrodes 13a to 13c are each an insulating substrate. Electrical connection is made between the front and back sides via semicircular notch-shaped side surface electrodes 13d, 13e, 13f formed on the side surfaces of twelve. The capacitive element 14 is a front electrode 15a,
Also, by the front side electrode (not shown) and the back side electrode 15b which are symmetrical to this, two capacitors in the longitudinal direction (see FIG.
A, B) of each of the electrodes 13a, 13b, 13c of the insulating substrate 12 and each electrode 1 of the capacitive element 14
5a and 15b are connected by the conductive adhesive 16 to the first electrode 13a and the front side electrode 15a, the second electrode 13b and the back side electrode 15b, and the third electrode 13c and the front side electrode.

The piezoelectric vibrating element 17 is a thin plate and has a front electrode 18.
a and the back side electrode 18b are provided, and both ends in the longitudinal direction are formed by the conductive adhesive 16 on the front side electrode 1 of the capacitive element 14.
5a and the front side electrode 18a of the piezoelectric vibrating element 17, and the front side electrode and the back side electrode 18b are connected respectively. The cap case 19 is a box having a U-shaped cross section, and accommodates the capacitive element 14 and the piezoelectric vibrating element 17, and its opening is fixed on the insulating substrate 12 with an adhesive.

FIG. 9 shows the above structure in an equivalent circuit.

[0006]

However, in the above conventional structure, the piezoelectric vibrating element 17 is mounted on the insulating substrate 12, and the cap case 19 is bonded to the substrate 12 so as to house the piezoelectric vibrating element 17. , At both ends of the element,
Due to the amount of the conductive adhesive 16 applied and restrictions on assembly accuracy, it is necessary to provide a dimensional allowance between the conductive adhesive 16 and the cap case 19, and the product size in the length direction of the piezoelectric vibrating element 17 becomes large. There was a problem. Further, since an adhesive is used for joining the cap case 19 and the insulating substrate 12, it is different from the conductive adhesive 16 used when the piezoelectric vibrating element 17 is adhesively fixed to the insulating substrate 12. Due to the difference in the curing conditions, the adhesive curing step is required multiple times, and there is a problem in terms of mass productivity.
Therefore, the present invention aims at downsizing and improvement in mass productivity.

[0007]

In order to achieve this object, the piezoelectric vibrator of the present invention has a case having a U-shaped cross section, a substrate joined to an opening of the case, and a case inside the case. A piezoelectric vibrating element accommodated therein and a metal plate adhered and fixed to a side surface of the case with a conductive adhesive are provided, and the piezoelectric element in the case is adhesively fixed to the metal plate with the conductive adhesive.

[0008]

With this configuration, it is not necessary to provide a space for a dimension allowance at both ends of the piezoelectric vibrating element, and the product length dimension can be made substantially the same as the piezoelectric vibrating element length dimension. Since the element and the metal plate can be adhesively fixed at the same time by using the same conductive adhesive, the production process can be simplified.

[0009]

【Example】

(Embodiment 1) An embodiment of the present invention will be described below with reference to the drawings.

In FIGS. 1 and 2, reference numeral 1 denotes a case having a U-shaped cross section, in which an insulating substrate 2 is joined to the lower opening and metal plates 6 are joined to both side openings.

The metal plate 6 used here is slightly smaller than the outer peripheral size of the joined body of the case 1 and the insulating substrate 2, so that a part of the metal plate 6 does not protrude from the product. I have to.

FIG. 3 is a sectional view taken along the line YY 'in FIG. 1, showing the internal structure. In FIG. 3, only the left half is shown because it is bilaterally symmetrical. A piezoelectric vibrating element 3 is housed inside the case 1. The piezoelectric vibrating element 3 has a thin plate shape and is provided with a front electrode 4a and a back electrode 4b. Both ends thereof are electrically and mechanically connected to the thin metal plate 6 installed on the side surface by the conductive adhesive 5.

FIG. 4 is a cross-sectional view of the product of FIG. 1 taken along the line XX ', showing that the piezoelectric vibrating element 3 is bonded and fixed to the case 1 and the substrate 2 by the conductive adhesive 5. Is. FIG. 4 also shows only the left half for the sake of left-right symmetry.

As described above, according to this embodiment, the lengthwise dimension of the product can be made substantially the same as the length of the piezoelectric vibrating element 3, and the product can be miniaturized.

Further, as shown in FIG. 5, as the insulating substrate 7, one having electrodes 8a, 8b and 8c provided on the surface of the dielectric to form a capacitance between the electrodes 8a-8b and 8c-8b is used. , An end face electrode 9a connected to the electrode 8a, and an end face electrode 9c connected to the electrode 8c are connected to the metal plate 6 via the conductive adhesive 5 to form an equivalent circuit shown in FIG. The piezoelectric vibrator can be configured.

The side surface of the insulating substrate 7 is connected to the electrode 8b so that the soldering state of the electrode 8b can be confirmed from the side surface when mounted on the wiring board by soldering.
b is formed.

Further, as shown in FIG. 6, at least one convex portion 10 and 11 are provided on the inner side surface of the U-shaped case 1 and the insulating substrate 2 (or 7) on the storage side of the piezoelectric vibrating element 3. By forming or attaching the piezoelectric vibrating element 3, it is possible to prevent the surface of the piezoelectric vibrating element 3 from coming into close contact with the surface of the case 1 or the insulating substrate 2, and it is possible to reliably secure a space required for vibration. The convex portions 10 and 11 are formed of the conductive adhesive 5
Since it is possible to expect the effect of preventing the flowing of the piezoelectric vibrating element 3 from the end portion to the central portion, two pieces are formed on each side of the case 1 and the insulating substrate 2 as shown in the embodiment of FIG. are doing.

[0018]

As described above, according to the present invention, a metal plate is bonded to a side opening of a case having a U-shaped cross section and a substrate joined to the opening of the case with a conductive adhesive. At the same time, since the internal piezoelectric element is also bonded by this conductive adhesive, the longitudinal dimension of the product can be made almost the same as the length of the piezoelectric vibrating element, and the size can be reduced and the conductive adhesive can be used. Thus, the piezoelectric vibrating element and the metal plate can be bonded and fixed and electrically connected at the same time in a single step, so that mass productivity can be improved.

[Brief description of drawings]

FIG. 1 is a perspective view of a piezoelectric vibrator showing an embodiment of the present invention.

FIG. 2 is an exploded perspective view showing an embodiment of the present invention.

FIG. 3 is an enlarged sectional view of an essential part of a piezoelectric vibrator showing an embodiment of the present invention.

FIG. 4 is an enlarged sectional view of an essential part of a piezoelectric vibrator showing an embodiment of the present invention.

FIG. 5 is a perspective view of a substrate showing an embodiment of the present invention.

FIG. 6 is an enlarged sectional view of an essential part of a piezoelectric vibrator showing an embodiment of the present invention.

FIG. 7 is a perspective view of a conventional piezoelectric vibrator.

FIG. 8 is an enlarged sectional view of a main part of a conventional piezoelectric vibrator.

FIG. 9: Equivalent circuit diagram of built-in capacitor type piezoelectric vibrator

[Explanation of symbols]

 1 Case 2 Substrate 3 Piezoelectric Vibrating Element 5 Conductive Adhesive 6 Metal Plate

Claims (3)

[Claims] 1. A case having a U-shaped cross section, a substrate joined to an opening of the case, a piezoelectric vibrating element housed inside the case, and a side surface of the case bonded by a conductive adhesive. A piezoelectric vibrator comprising a fixed metal plate, and a piezoelectric vibrating element in a case adhered and fixed to the metal plate by the conductive adhesive. 2. The piezoelectric vibrator according to claim 1, wherein the substrate has an electrode on its surface that forms an electrostatic capacitance. 3. The case and the substrate are provided with at least one or more protrusions on the inner surface sides of both ends thereof.
The piezoelectric vibrator according to item 1.