JPH0265517A - Piezoelectric oscillator - Google Patents

Abstract

PURPOSE:To make the outer size of the piezoelectric oscillator small by clipping a piezoelectric substrate and a spacer from the front side and the rear side as sandwich and integrating the piezoelectric substrate, the spacer, the surface sheet and the rear sheet through the adhesion except the vicinity of at least a tuning fork part. CONSTITUTION:The piezoelectric substrate 2 and the spacer 4 are clipped as a sandwich by the surface side sheet 5 and the rear side sheet 6 in the piezoelectric oscillator 1 and integrated by adhesives 7, 8 as a basic structure. A tuning fork 2a is formed to one side of a square of the piezoelectric substrate 2. The spacer 4 is a plate having nearly the same thickness as that of the piezoelectric substrate 2 and butted to the tuning fork 2a of the piezoelectric substrate 2 by opening an air gap 3. Since the adhesives 7, 8 are flowed to both ends 3a of the air gap 3, the air-tightness of the tuning fork 2a is kept. The outer size of the piezoelectric oscillator 1 is increased than the size of the piezoelectric substrate 2 by the size of the spacer 4, but the size is close to the size of the piezoelectric substrate 2. Thus, miniaturization is attained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a piezoelectric transducer, and more particularly, to a piezoelectric transducer having a structure that can be miniaturized and easily mass-produced.

[Conventional technology]

An example of a conventional piezoelectric vibrator is shown in FIGS. 6 and 7.

This piezoelectric vibrator 101 connects a piezoelectric substrate 102 having a tuning fork portion 1021 to electrodes 1031 and 103 for connection with the outside.
The piezoelectric substrate 10 is glued onto the base plate 103 on which the
A frame-shaped spacer 104 is bonded so as to surround 2, and a lid plate 105 is further bonded.

[Problem to be solved by the invention]

In the conventional piezoelectric vibrator 101 described above, the frame-shaped spacer 104 is larger in size than the piezoelectric substrate 102, and the base plate 103 is also larger in size than the frame-shaped spacer 104.

That is, even if the size of the piezoelectric substrate 102 is reduced to its limit, there is a problem in that the external size of the piezoelectric vibrator 101 becomes twice as large.

Furthermore, a piezoelectric substrate 102 and a base plate 103.

There are manufacturing difficulties such as the necessity of accurately positioning the frame-shaped spacers 104 relative to each other, which makes mass production difficult.

Therefore, an object of the present invention is to provide a piezoelectric vibrator that can be reduced in external size and has a structure that is easy to mass produce.

[Means to solve the problem]

The piezoelectric vibrator of the present invention has a piezoelectric substrate having a tuning fork forming side, a spacer disposed so as to butt against the tuning fork forming side of the piezoelectric substrate, and a sandwich between the piezoelectric substrate and the spacer. The piezoelectric substrate, the spacer, the front sheet, and the back sheet are integrated by adhesive except at least near the tuning fork portion. This is a structural feature.

[Effect]

Since the piezoelectric vibrator of the present invention has a structure in which a piezoelectric substrate and a spacer are sandwiched between a front sheet and a back sheet, the external size of the piezoelectric vibrator is extremely larger than the size of the piezoelectric substrate. Never.

Therefore, the size of the piezoelectric substrate can be reduced (close to the limit possible), and the external size of the piezoelectric vibrator can be reduced.

In addition, since it can basically be manufactured by pasting together three plate-like materials, the manufacturing process is reduced and mass productivity is improved.

Furthermore, since the piezoelectric substrate is fixed except for the vicinity of the tuning fork, the characteristics are also improved.

〔Example〕

Hereinafter, the present invention will be explained in more detail based on an example shown in the figures. 1 is a perspective view of a piezoelectric vibrator according to an embodiment of the present invention, FIG. 2 is an exploded perspective view of the piezoelectric vibrator shown in FIG. 1, and FIG. 3 is a perspective view of a piezoelectric vibrator according to another embodiment of the present invention. FIG. 4 is a diagram corresponding to FIG. 2 of a piezoelectric vibrator according to still another embodiment of the present invention, and FIG. 5 is a diagram corresponding to FIG. 2 of a piezoelectric vibrator according to yet another embodiment of the present invention. This is a diagram equivalent to Figure 2. Note that the present invention is not limited to the following examples.

As shown in FIG. 1, the piezoelectric vibrator 1 has a basic structure in which a piezoelectric substrate 2 and a spacer 4 are sandwiched between a front sheet 5 and a back sheet 6, and are integrated with an adhesive 78. are doing.

As shown in the second WJ, the piezoelectric substrate 2 has a tuning fork portion 2 on one side of the rectangle. was formed. 2T is a slit for forming a tuning fork portion, and 2c is a slit for separating the tuning fork portion. Electrodes 2J and 2.2 are provided on the front and back surfaces near the deepest part of the tuning fork forming slit 2b, respectively. is formed. Further, electrodes 2f and 2g for connection with the outside are provided on the front side and the back side, respectively.

The spacer 4 is a plate-shaped body having approximately the same thickness as the piezoelectric substrate 2.
Tuning fork portion 2 of piezoelectric substrate 2. They are arranged so that they are butted against each other with a gap 3 between them.

The front side sheet 5 and the back side sheet 6 are approximately equal in size to the combined size of the piezoelectric substrate 2 and the spacer 4, and have cutout portions 5m+5b and 8m, 8b, and are further coated with adhesives 7 and 8 along their peripheries. It is coated.

When the piezoelectric substrate 2 and the spacer 4 are sandwiched between the front side sheet 5 and the back side sheet 6, because the adhesives 7 and 8 are thick, at least the tuning fork part 21 of the piezoelectric substrate 2
A void is formed near the . Therefore, the tuning fork portion 2. piezoelectric vibrations are not disturbed.

Further, as shown in FIG. 1, since the adhesives 7 and 8 flow into both end portions 31 of the gap 3, the airtightness of the tuning fork portion 2□ is maintained.

The external size of the piezoelectric vibrator 1 is larger than the size of the piezoelectric substrate 2 by the size of the spacer 4, but is closer to the size of the piezoelectric substrate 2 than in the past. Therefore, it can be made smaller.

Furthermore, since it can be manufactured basically by a technique of bonding plate-like objects together, it is easy to manufacture and has excellent mass productivity.

Further, although there is a gap near the tuning fork portion 21, since the area around the gap is fixed with the adhesive 7.8, vibrations are well confined and the characteristics are improved. - In the example, the peak-to-valley ratio of the frequency characteristics was improved from about 50 dB to about 60 dB.

Note that either one or both of the adhesives 7 and 8 may be applied to the piezoelectric substrate 2 and the spacer 4.

Next, a piezoelectric vibrator 11 shown in FIG. 3 shows another embodiment of the present invention.

In this piezoelectric vibrator 11, the tuning fork portion 12. In this case, an electrode 12J is formed along the edge of the tuning fork forming ring 12b, and electrodes 128 are provided on both sides of the electrode 12-. Further, although not shown in the figure, an electrode is provided on the back surface, which is commonly opposed to the electrodes 12a and 12°. 12112g is a connection electrode to the outside, and a notch 11 is provided in the front sheet 15 to match these positions.
5M, 15& are formed. Since the connection electrodes 12+12 are provided only on the front side, the back sheet 16 is not provided with a cutout.

An adhesive 17 is applied along the periphery of the front sheet 15, and an adhesive 18 is applied along the periphery of the back sheet 16, thereby bonding the piezoelectric substrate 12, spacer 4, front sheet 15, and front side together. The sheet 16 is bonded and integrated.

Next, FIG. 4 shows a piezoelectric vibrator 2 according to still another embodiment of the present invention.
1.

The difference from the piezoelectric sensor 11 of the above embodiment is that the front sheet 15 of the piezoelectric sensor 11 is further provided with a notch [25].
c is provided, and each notch 25m, 25b, 25
Electrodes 25J, 25°, and 25f are formed along the periphery of c, and electrodes 25e and 25C are connected by a connecting electrode 25.

In addition to the spacer 4, an electrode 24. is formed. Such changes are made to improve connectivity with the outside world.

Next, FIG. 5 shows a piezoelectric vibrator 31 according to still another embodiment of the present invention.

In this piezoelectric vibrator 31, the tuning fork portion 321 of the piezoelectric substrate 32
The difference is that the spacer 34 has a convex structure that protrudes outward, and the spacer 34 has a concave structure corresponding to the convex structure of the piezoelectric substrate 32, but the other differences are shown in FIG. It has the same structure as the piezoelectric vibrator 11.

〔Effect of the invention〕

According to the present invention, a piezoelectric substrate having a tuning fork forming side, a spacer disposed so as to butt against the tuning fork forming side of the piezoelectric substrate with a gap, and the piezoelectric substrate and spacer are sandwiched together. The piezoelectric substrate, the spacer, the front sheet, and the back sheet are integrated by adhesive except for at least the vicinity of the tuning fork. A piezoelectric vibrator with a characteristic feature is provided, which makes it possible to reduce the external size of the piezoelectric vibrator to close to the size of a piezoelectric substrate. Moreover, manufacturing is easy and mass productivity is excellent.

Furthermore, the properties are also excellent.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a piezoelectric vibrator according to an embodiment of the present invention, and FIG.
1 is an exploded perspective view of the piezoelectric vibrator shown in FIG. 1, FIG. 3 is a view corresponding to FIG. 2 of a piezoelectric vibrator according to another embodiment of the present invention, and FIG. FIG. 5 is a view corresponding to FIG. 2 of a piezoelectric vibrator, FIG. 5 is a view corresponding to FIG. 2 of a piezoelectric sensor according to yet another embodiment of the present invention, and FIG. 7 is an exploded perspective view of the piezoelectric vibrator shown in FIG. 6 [Explanation of symbols] 1.11, 21.31...Piezoelectric vibrator 2.12.32
. . . Piezoelectric substrate 2, tza, 32. ...Tuning fork part 3.13, 23.33...Gap 4.24.34...Spacer 5.15.25...Front side sheet 6.16...Back side sheet 7.8, 17 .18...Adhesive.

Claims (1)

[Claims] 1. A piezoelectric substrate having a tuning fork forming side, a spacer disposed so as to butt against the tuning fork forming side of the piezoelectric substrate with a gap, and a front side and a back side of the piezoelectric substrate and spacer sandwiched together. A piezoelectric vibrator comprising a front sheet and a back sheet sandwiched between the piezoelectric substrate, the spacer, the front sheet, and the back sheet, which are integrated by adhesive except at least near the tuning fork part. .