JPH07120917B2 - Piezoelectric vibrator - Google Patents

Description

TECHNICAL FIELD OF THE INVENTION The present invention relates to a piezoelectric vibrator capable of significantly reducing the overall thickness.

(Technical background of the invention and its problems) Generally, a large number of piezoelectric vibrators are used in a wide field of electronic technology, and in particular, a crystal vibrator using a crystal piece as a piezoelectric body has high frequency stability and communication. It is widely used as a time and frequency reference source for equipment, digital control equipment, etc.

In particular, the demand for piezoelectric vibrators has increased in recent years as electronic devices have become smaller and more sophisticated, and cost reduction and miniaturization have progressed at a rapid tempo. In addition, surface mounting technology has become thinner and surface mounting is possible. A piezoelectric vibrator is desired.

Therefore, for example, a piezoelectric vibrator in which a crystal element is held on a plate-shaped base made of ceramic or the like and a cover is placed on the crystal element has been put into practical use.

FIG. 4 is a side sectional view showing an example of such a piezoelectric vibrator. A metal holding piece 2 is fixed to a plate-shaped base 1 made of ceramic, and both ends of a crystal piece 3 are fixed to the holding piece 2. Hold.

Then, the crystal piece 3 is formed on the plate surface of the base 1 through the conductive pattern 4 formed by, for example, a metallizing process.
The electrode formed in the above is led out. A box-shaped ceramic lid 5 having an open bottom is covered on the base 1 to hermetically seal it.

By doing so, the heat resistance of the ceramic used for the base 1 and the lid 5 is good, and the base 1 and the lid 5 are good.
The same material has the same coefficient of thermal expansion, and the reliability can be improved without causing damage such as cracking or chipping even when it is mounted on a printed circuit board and heated for soldering, for example.

However, the ceramic container as shown in FIG. 4 cannot be used for a card type electronic device having a thickness of, for example, about 1 mm because the thickness cannot be made so thin.

For this reason, the Japanese Patent Application No. 62-
As in 161494, it is conceivable that the electrodes are led out to both ends of the piezoelectric body and connected to a thin plate-shaped lead plate, and this lead plate is sandwiched from both sides of the plate surface via a sheet impregnated with an adhesive. ing.

By the way, in such a device, lead plates are fixed in advance to both ends of the piezoelectric body having electrodes formed on the plate surface, and both plate surface sides of the lead plate are sandwiched by a pair of shells having recesses formed on opposite surfaces, High accuracy is required for positioning the lead plate with respect to the shell during assembly, which may cause problems such as poor appearance and deterioration of electrical characteristics due to contact between the piezoelectric body and the shell in extreme cases.

(Object of the Invention) The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a piezoelectric vibrator capable of significantly reducing the overall thickness and easy to assemble. Is.

(Summary of the Invention) According to the present invention, a strip-shaped lead plate is fixed to both ends of a strip-shaped piezoelectric body having electrodes formed on both side plate surfaces, and a recess is formed in the central portion with the same width dimension as the lead plate. It is characterized in that the lead plate is sandwiched between a pair of strip-shaped shells and a sheet impregnated with an adhesive to hermetically seal the piezoelectric body.

(Embodiment) An assembly perspective view showing an embodiment of the present invention shown in FIG.
This will be described in detail with reference to the plan view shown in the drawing and the sectional view of the main part shown in FIG.

11 in the figure, for example, cut a crystal of quartz at a predetermined angle,
This is a piezoelectric body that is formed into a rectangular plate shape and is provided with electrodes 11a on both side plate surfaces, and the electrodes 11a are led to both ends in the longitudinal direction and the connection electrodes 11b.

Then, both ends of the piezoelectric body 11 are respectively fixed to lead plates 12 formed by stripping a thin metal plate such as nickel silver in a strip shape and extended outward, and each lead plate 12 is connected to the connection electrode 11b. It is electrically connected.

Incidentally, a cut 12a is provided on both sides of the portion of the lead plate 12 to which the piezoelectric body 11 is fixed so as to mitigate external impacts or the like acting on the piezoelectric body, and a through hole 12b is further formed in the central portion. The lead plate 12 is formed so as to enhance its elasticity.

Then, facing the both side plate surfaces of the lead plate 12, for example, a recess 13a is formed in the central portion of the facing surface made of a metal thin plate such as SUS304, the width dimension is equal to the lead plate,
A pair of strip-shaped shells 13 are provided.

Then, between the shells 13 and the lead plate 12, a through hole 14a is formed in the central portion corresponding to the recess 13a of the shell 13, and the sheet is made of, for example, glass fiber impregnated with an adhesive. 14 and the lead plate through the sheet 14.
The shell 12 is sandwiched by the shell 13 from both sides and adhered to be hermetically sealed. The sheet 14 thus impregnated with the adhesive is non-conductive, so that the lead plate 12 is fixed to the shell 13 and the two are electrically insulated.

Further, since the width dimensions of the shell 13 and the lead plate 12 are made equal to each other, the positioning can be easily performed by aligning the widthwise edges of the two.

Further, in the above-mentioned embodiment, the thickness of the lead plate 12 located outside the shell 13 is made thicker than the thickness of the lead plate 12 inside the shell 13 and at the penetrating portion, so that the longitudinal direction of the shell 13 The lead plate 12 can be easily positioned with respect to the lead plate, which has the advantage of significantly improving productivity.

In this way, for example, the lead plate 12 and the sheet 14
The thickness of the shell can be set to 0.05 mm and the thickness of the shell 13 can be set to about 0.5 mm,
The total thickness after assembly can be reduced to about 1 mm.

Therefore, it can be used for card type electronic devices,
It is possible to provide a piezoelectric vibrator that is easy to assemble and inexpensive.

The present invention is not limited to the above embodiment,
For example, the shell 13 may be glass, ceramic, or the like,
Of course, these surfaces may be coated with a metal so as to be shielded.

(Effects of the Invention) As described in detail above, according to the present invention, it is possible to provide a piezoelectric vibrator that can be remarkably thin and that can be used in a card-type electronic device.

[Brief description of drawings]

FIG. 1 is an assembly perspective view showing an embodiment of the present invention. FIG. 2 is a plan view showing a state where the piezoelectric body shown in FIG. 1 is fixed to a lead plate, and FIG. 3 is a main part of the embodiment. FIG. 4 is a side sectional view showing an example of a conventional thin piezoelectric vibrator. 11 …… Piezoelectric body 12 …… Lead plate 13 …… Shell 14 …… Sheet

Claims (3)

[Claims] 1. A strip-shaped piezoelectric body in which electrodes are formed on both side plate surfaces, and the electrodes are led out to both ends in the longitudinal direction, and the piezoelectric body is fixed to both ends of the piezoelectric body and extends outwardly, and each of the electrodes is formed. A strip-shaped lead plate electrically connected to, and a pair of shells each having a width equal to the lead plate and having a recess formed in the central portion of the facing surface to sandwich the lead plate from both sides of the plate surface, And a sheet made of fiber impregnated with an adhesive, which has a through hole in the central portion corresponding to the recess and is interposed on both sides of the lead plate on the opposed surfaces of the pair of shells. Piezoelectric vibrator. 2. The piezoelectric vibrator according to claim 1, wherein notches are provided on both sides of a portion of the lead plate to which the piezoelectric body is fixed. 3. The device according to claim 1, wherein a thickness of a portion of the lead plate located outside the shell is smaller than a thickness of a portion inside the shell and a portion passing through the shell. A piezoelectric vibrator characterized by being thickened.