JPH052010B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a chip-type piezoelectric resonator, and particularly to a structure in which a rectangular piezoelectric resonator is arranged and fixed in a hollow part of a hollow cylindrical insulating case. The present invention relates to a chip-type piezoelectric vibrator having a chip-type piezoelectric vibrator.

[Prior art]

This type of chip-type piezoelectric vibrator is already known.

[Problem to be solved by the invention] Conventionally, conductive adhesives are used to connect and fix piezoelectric resonators, so it is difficult to arrange the piezoelectric resonators in an appropriate state in an insulating case. They were often arranged as shown in Figures and 9B.

In the case shown in FIG. 9A, the entire piezoelectric resonator 2 descends so as to come into contact with the bottom of the inner wall of the hollow part of the insulating case 1. On the other hand, in the case shown in FIG. 9B,
One end of the piezoelectric resonator 2 is lowered and disposed obliquely. In such cases, piezoelectric resonator 2
The gap between the inner wall surface of the insulation case 1 and the inner wall surface of the insulation case 1 becomes smaller.

Therefore, the conductive adhesives 4a and 4b enter this gap more than necessary until the conductive adhesive 4 hardens due to capillary action.
If this happens, the conductive adhesive 4a or 4b will adhere to the vibrating part, making it impossible to perform good vibration, and in some cases, the conductive adhesive 4a or 4b will adhere to the vibrating part.
and the electrode 3, or the conductive adhesive 4b and the electrode 5 become short-circuited.

Therefore, for example, in May 1981, the applicant
Utility model application published on the 19th, 1987-
The prior art of Publication No. 73832 was proposed. However, in this conventional technology, since the solid part is fixed to the piezoelectric element, the leakage of vibration from the vibrating part of the piezoelectric element is reflected by the solid part, which adversely affects the main vibration in the vibrating part of the piezoelectric element, causing vibration. This will worsen the characteristics.

Therefore, the main object of the present invention is to provide a chip-type piezoelectric vibrator that can be easily placed inside an insulating case without deteriorating its vibration characteristics, and that is less likely to produce defective products due to capillary action. It is to be.

[Means to solve the problem]

Simply put, this invention includes a cylindrical insulating case, a piezoelectric resonator that includes a piezoelectric substrate having an energy-trapping vibrating part and is placed in a hollow part of the insulating case, and a piezoelectric resonator that is placed over both ends of the insulating case. A chip-type piezoelectric vibrator comprising a cap and electrically connecting a piezoelectric resonator to the cap includes a plate member and a pair of cut-and-raised pieces cut and raised from the plate member, each having a base portion and a tip. The plate member of the spacer is sandwiched between the end face of the insulating case and the cap, and holds the piezoelectric resonator on one side of the base and the tip of the cut-and-raised piece, thereby making the piezoelectric resonator hollow. This chip-type piezoelectric vibrator is characterized in that it is held by the elasticity of the cut and raised pieces so as not to come into contact with the inner wall of the part.

[Effect]

To describe an example of assembly, first, a spacer and a cap are fitted to one end of a cylindrical insulating case.
At this time, the plate member of the spacer is held between the end face of the insulating case and the cap. Then, insert the piezoelectric resonator into the cylindrical insulating case from the other end where the spacer and cap are not fitted, and connect one end of the piezoelectric resonator to the base of the cut and raised piece of the fitted spacer and Hold it on one side of the tip. Then, a spacer and a cap are fitted to the other end of the insulating case to hold the piezoelectric resonator so that the other end of the piezoelectric resonator is held in the same manner. Then,
The piezoelectric resonator is supported at both ends by spacers so as not to contact the inner wall of the hollow portion of the insulating case. In this case, a conductive adhesive is applied to the inside of the cap to integrally fix the piezoelectric resonator, insulating case, and spacer. The assembly method is not limited to the one described above, but in any case, the spacer maintains an appropriate distance between the piezoelectric resonator and the hollow inner wall of the insulating case.

Further, since the piezoelectric resonator is fixed without being fixed to the spacer, vibration leakage from the vibrating portion of the piezoelectric resonator is absorbed by the spacer and does not affect the main vibration.

〔Effect of the invention〕

According to this invention, since the piezoelectric resonator is held by the spacer, the piezoelectric resonator can be easily placed at an appropriate position within the insulating case without using a complicated jig. This spacer therefore greatly simplifies assembly. In addition, if the height at which the spacer holds the piezoelectric resonator is set at a height that does not cause capillary action between the piezoelectric resonator and the insulating case, the conductive adhesive will hold the piezoelectric resonator due to capillary action. It does not extend to the vibrating part. Furthermore, if the spacer is made of metal,
Reliability is improved because the piezoelectric resonator and the cap are electrically connected not only through the conductive adhesive but also through the spacer. in this way,
According to this invention, the occurrence of defective products can be reduced as much as possible.

Furthermore, since the spacer absorbs vibration leakage from the vibrating part, it does not affect the main vibration, and good vibration characteristics can be obtained.

The above objects, other objects, features and advantages of the present invention will become more apparent from the following detailed description of embodiments with reference to the drawings.

〔Example〕

FIG. 1 shows a sectional view of an embodiment of the present invention,
Figure 2 shows an external view. Caps 12 made of a conductive material such as phosphor bronze are press-fitted into both ends of the hollow cylindrical insulating case 10. The insulating case 10 is made of ceramic such as alumina. Appropriate radii are formed at the outer corners 10a at both ends of the cylindrical insulating case 10 so that the cap 12 can be easily press-fitted therein. It is desirable that the curvature of this corner 10a be smaller than the curvature of the inside radius of the cap 12 that is placed over it. When the radius of the cap 12 is made larger than the radius of the insulating case 10, the cap 1
When press-fitting 2, it is not only easy to press-fit, but also
Cap 12 and electrode 14 on both rounded surfaces
(FIG. 1) are reliably electrically connected, and the reliability of electrical continuity is improved.

As shown in FIG. 3, electrodes 14 having a uniform thickness are formed at both ends of the insulating case 10 so as to surround the rounded corners 10a. This electrode 14 is made of a metal such as Ag, Cu, or Ni, and is formed, for example, by baking.

Thickness p of the electrode 14 from the outer surface of the insulating case 10
The insulating case 10 and cap 12 shown in FIG.
It is set according to the interval q between However, it is better that this thickness p is not too large. This is because if the thickness p is too large, the above-mentioned interval q becomes too large, making the chip shape unfavorable.

Note that in order to reduce the wall thickness p of the electrode 14 on the outside of the insulating case 10, the above-mentioned insulating case 10
It is effective that the corner 10a of is rounded. If such a radius is formed, the outer surface becomes thinner when applying conductive paste for the electrodes 14 to both ends of the insulating case 10 using, for example, a roller.

As shown in FIG. 4, the piezoelectric resonator 16 has vibrating electrodes 18 and 20 formed on its upper and lower surfaces, which partially overlap, as in the conventional piezoelectric resonator. However, the other end of one of the vibrating electrodes 18 and 20 is folded back from the main surface where the vibrating electrodes 18 and 20 are formed, so that the end portions 18a and 20a are
Each is formed to extend to the opposite main surface. The reason for forming the folded end portions 18a and 20a in this manner is to ensure good electrical continuity between the spacer and the vibrating electrodes 18 and 20, which will be described later. At the portion where the vibrating electrodes 18 and 20 overlap approximately in the center of the piezoelectric resonator 16, energy-trapped thickness shear vibration occurs.

As shown in a perspective view in FIG. 5A, the spacer 22 is formed by punching and molding a disk-shaped metal plate, for example, phosphor bronze, as a plate member. In other words, if you make two incisions on opposite sides of a circular metal plate and bend it downward, you get
Tongue-shaped cut and raised pieces 22a and 22b each having a base and a tip are formed. Cut and raised piece 2
The angle at which 2a and 22b are bent is the fifth
As shown in the cross-sectional view in FIG. B, the angle is set to be smaller than 90°, and the width of the base portions of the cut and raised pieces 22a and 22b is formed smaller than the thickness of the piezoelectric resonator 16. During assembly, the ends 18a and 20a are held together by the elastic restoring force of the cut-and-raised pieces 22a and 22b that have been pushed apart by the piezoelectric resonator 16 after the piezoelectric resonator 16 is inserted. This is to ensure good electrical continuity between the spacer 22 and the vibrating electrodes 18 and 20 by sandwiching them.

For example, the insulating case 10, piezoelectric resonator 16, and spacer 22 are assembled as follows. As shown in FIG. 6, the spacer 22 is first fitted into the insulating case 10 so that the cut and raised pieces 22a and 22b are placed in the hollow portion at one end. After that, from the other end where the spacer 22 is not fitted, the piezoelectric vibrator 16
is inserted into the hollow part of the insulating case 10, and the ends thereof are cut and raised and fitted between the respective base parts of the pieces 22a and 22b. Then, the cut and raised pieces 22a and 2
The end of the vibrating electrode 18 or 20 is clamped by the elastic restoring force of the vibrating electrode 2b. And piezoelectric resonator 1
Another spacer 22 is fitted to the end of the insulating case 10 on the side where the spacer 6 is inserted. Then,
As shown in FIG. 6, the ends of the piezoelectric resonator 16 are held between cut and raised pieces 22a and 22b, respectively.
It is integrally fixed to the insulating case 10 by a spacer 22.

Note that when the piezoelectric resonator 16 is held by the spacer 22, the circular plane of the spacer 22 is in close contact with the circular electrode 14 formed on the end surface of the insulating case 10.

After arranging the piezoelectric resonator 16, the insulating case 10
At both ends of the cap 12, a conductive adhesive 24 is applied on the inside, and the cap 12 is fitted as shown in FIG. At this time, a sufficient gap is maintained between the surface of the piezoelectric resonator 16 and the inner wall of the hollow part of the insulating case 10 by the spacer 22, and the conductive adhesive 24 is applied to the piezoelectric resonator 16 by capillary action. It does not extend to the above-mentioned vibrating part. That is, since the spacer 22 arranges the piezoelectric resonator 16 at a predetermined position, capillary action of the conductive adhesive 24 is prevented.

Note that the inner corner 12a of the cap 12 is provided with a radius having the same center of curvature as the radius provided at the corner 10a of the insulating case 10, but having a different curvature, as described above.

When the press-fitting of the cap 12 is completed, the outer thickness p of the electrode 14 is deformed by the press-fitting, and becomes as shown in FIG. Then, the insulating case 10 and the cap 12 are completely fixed together. Then, when the conductive adhesive 24 hardens, the piezoelectric resonator 16 is fixedly held within the insulating case 10. At the same time, the electrodes 18 and 20 of the piezoelectric resonator 16 and the spacer 22 are each completely electrically connected to the cap 12 via the conductive adhesive 24.

Note that the spacer 22 shown in FIG. 7A and FIG.
Those shown in FIG. B, FIG. 8A, and FIG. 8B may be used.

Like the spacer 22, the spacer 26 shown in FIGS. 7A and 7B is formed from a circular metal plate serving as a plate member, but the cut and raised pieces 26a and 26b, each having a base and a tip, are made of a metal plate. It is formed by making a parallel cut approximately in the center, cutting the cut into two parts, and bending the cut in half. The piezoelectric resonator 16 is held by the tips of the cut and raised pieces 26a and 26b. With such a shape, the cut and raised pieces 26a and 26b also function as a guide for causing the conductive adhesive to flow intensively to the piezoelectric resonator.

The spacer 28 shown in FIGS. 8A and 8B is a cut-and-raised piece 28a similar to that shown in FIGS. 7A and 7B.
In addition to 28b and 28b, cut-and-raised portions 28c and 28d are formed to face the ends of the circular metal plate. These cut and raised portions 28c and 28d connect the electrode 14 formed on the insulating case 10 and the cap 1.
In other words, a repulsion force due to elastic restoring force is always generated between the electrode 14 and the cap 12 to ensure good electrical continuity between the electrode 14 and the cap 12.

Note that a solder paste may be used instead of the conductive adhesive used in the above embodiment.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of the present invention. FIG. 2 is an external perspective view of this embodiment. FIG. 3 is an illustrative cross-sectional view showing a state in which electrodes are formed at both ends of the insulating case. FIG. 4 is a perspective view showing the state of the vibrating electrode formed on the piezoelectric resonator. Fifth
FIG. 5B is a perspective view showing an example of the spacer shown in FIG.
The figure is a sectional view taken along line BB in FIG. 5A. FIG. 6 is an illustrative cross-sectional view for explaining the state in which a cap is press-fitted into an insulating case on which electrodes are formed. 7A and 7B show other examples of spacers, with FIG. 7A being a perspective view and FIG. 7B being a sectional view taken along line AA in FIG. 7A.
FIGS. 8A and 8B show other examples of the spacer, with FIG. 8A being a perspective view and FIG. 8B being a sectional view taken along line BB in FIG. 8A. FIGS. 9A and 9B show cross-sectional views of a conventional chip-type piezoelectric vibrator. In the figure, 10 is an insulating case, 12 is a cap, 16 is a piezoelectric resonator, 22, 26, 28 are spacers, 22a, 22b, 26a, 26b, 28
28a and 28b are cut and raised pieces, and 24 is a conductive adhesive.

Claims (1)

[Scope of Claims] 1. A cylindrical insulating case, a piezoelectric resonator including a piezoelectric substrate having an energy trap type vibrating part and disposed in a hollow part of the insulating case, and a piezoelectric resonator placed over both ends of the insulating case. Equipped with a cap,
A chip-type piezoelectric vibrator that electrically connects the piezoelectric resonator to the cap, the spacer including a plate member and a pair of cut-and-raised pieces cut and raised from the plate member, each having a base portion and a tip. The plate member of the spacer is held between the end face of the insulating case and the cap, and holds the piezoelectric resonator at one of the base and the tip of the cut and raised piece, thereby holding the piezoelectric resonator. A chip-type piezoelectric vibrator, characterized in that the piezoelectric resonator is held by the elasticity of the cut-and-raised piece so as not to contact the inner wall of the hollow portion.