JPH03181216A - Piezoelectric parts - Google Patents

Abstract

PURPOSE:To miniaturize the piezoelectric parts by inserting a metallic terminal piece into a gap between a terminal electrode and the inner surface of a case, and holding the metallic terminal piece in its positioning state to the case by a piezoelectric element and also to electrically take the piezoelectric element out of the case. CONSTITUTION:When a metallic terminal piece 2 inserted into a gap between the terminal electrodes 1c/1d provided at both ends of a piezoelectric element 1 and the inner surface of a case 3 is made into a shape whose both ends are expanded in U-shape. Under such conditions, the element 1 can be held at an inner part 2e of the piece 2, furthermore the element 1 is naturally positioned to center on the case 3 when the both ends of the element 1 abut on the inner surface of the case 3. In addition, the element 1 can be positioned with only the piece 2 when one of both ends of the piece 2 is exposed out of the case 3. At the same time, the element 1 can be electrically taken out of the case 3 through both electrodes 1c and 1d even though no electrode to be taken out is included in the case 3.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a piezoelectric component in which a piezoelectric element is housed in a case.

Conventionally, a piezoelectric resonator, for example, is a piezoelectric component that has a rectangular shape inside a cylindrical case 23, as shown in FIG.
1, and caps 22 are placed on both ends of the cylindrical case 23, and the caps 22 and terminal electrodes 21a, 21a formed on both ends of the piezoelectric diaphragm 21 are connected to the conductive paste 2.
The configuration is electrically connected via 4.24. Note that 21b and 21c are electrodes for thickness shear vibration formed on the front and back surfaces of the piezoelectric diaphragm 21.

(The piezoelectric diaphragm is designed to
It is necessary to store it in a centered state within the cylindrical case. However, in the case of the above-mentioned configuration, since the case is cylindrical, it is difficult to center the case, and the conductive paste moves easily, making it difficult to connect the terminal electrode and the cap, making it difficult to mass-produce. Ta. Furthermore, since the case is circular, the hollow part is large relative to the piezoelectric component element, making the whole large.Conversely, if you try to make the case smaller, the above-mentioned centering will become increasingly difficult, and the conductive paste will not fit between the case and the piezoelectric diaphragm. There is a problem in that the capillary phenomenon that occurs in the gap between the two leads to a short-circuit.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an electronic component that is small in size, has excellent mass productivity, and has a structure that does not cause short circuits.

The first aspect of the present invention is a piezoelectric component in which a plate-shaped piezoelectric element is housed in a rectangular parallelepiped-shaped case, in which terminal electrodes are formed at both ends of the piezoelectric element, and the terminal electrode A conductive metal terminal piece is inserted into the gap between the piezoelectric element and the inner surface of the case, and this metal terminal piece holds the piezoelectric element in position with respect to the case, and allows electrical extraction to the outside of the case. It is characterized by being formed.

A second aspect of the present invention is a piezoelectric component in which a plate-shaped piezoelectric element is housed in a rectangular parallelepiped case, and thick terminal electrodes are formed at both ends of the piezoelectric element. The thick terminal electrode is characterized in that it holds the piezoelectric element in a positioned state with respect to the case, and is formed so as to have conduction with an external connection pattern provided on the case.

In the present invention, since the case is formed in the shape of a rectangular parallelepiped, the piezoelectric element is accommodated within the case without large gap fluctuations. In item 1, a metal terminal piece is inserted into the gap between the terminal electrodes formed at both ends of the piezoelectric element and the inner surface of the case, so that the U-shaped ends are wide, as will be explained later. If the piezoelectric element is shaped like this, the piezoelectric element can be held deep inside the metal terminal piece, and it will be positioned automatically when both ends are in contact with the inner surface of the case, so alignment is not required. The piezoelectric element can be centered with respect to the case. Furthermore, by leaving one end of the metal terminal piece exposed outside the case, the piezoelectric element can be positioned using only this metal terminal piece, and the terminal can be positioned even when no lead electrode is formed on the case. Electrical output can be taken from the electrode to the outside of the case.

In addition, in item 2, by forming the thick terminal electrodes formed on both ends of the piezoelectric element to an appropriate thickness, the piezoelectric element can be inserted into the case without the need for alignment. It can be centered with respect to the case, and has electrical continuity with the external connection pattern previously formed on the case.

Figure 1 is an exploded perspective view showing the case where the present invention is applied to a piezoelectric resonator. 1 in Figure 1 is a strip-shaped piezoelectric element made of a piezoelectric substrate such as a single crystal or ceramic; Electrodes 1a and lb are formed on the main surface of the horse in a state where they partially face each other, and terminal electrodes 1c and 1d are connected to the electrodes 1a and 1b at both ends.
is formed. Note that the electrodes 1a and lb are for thickness shear vibration, and are formed into a different predetermined shape when generating other vibration modes.

This piezoelectric element 1 has terminal electrodes 1c and ld with metal terminal pieces 2.
2 is inserted into the rectangular parallelepiped-shaped case 3, and then the case 3 is inserted into the opening 3a. 4 is installed and sealed.

The metal terminal piece 2 has four protruding portions 2a, 2b, and 2c of a rectangular plate with four corners cut off to form a substantially cross shape.
, 2d are bent to the same side, and has a U-shaped cross section with both ends widened.
Terminal electrode 1c on e.

1d is inserted into the case 3 together with the piezoelectric element 1. By this insertion, the protruding portions 2a and 2c that protrude upward and downward from the piezoelectric element 1 come into contact with the inner surface of the case 3 in a pressed state. Furthermore, when the lid 4 is attached to the opening 3a of the case 3 and sealed, the protrusions 2b and 2d protruding laterally from the piezoelectric element 1 are pressed against the inner surface of the case 3 facing 14. contact with.

Therefore, without positioning the piezoelectric element 1 with respect to the case 3, the piezoelectric element 1 is naturally centered in the height direction of the case 3 by the vertical protrusions 2a and 2c, as shown in FIG. At the same time, the piezoelectric element 1 is centered in the lateral direction of the case 3 at the lateral protruding portions 2b and 2d. In addition, the terminal electrodes 1c, l of the piezoelectric element 1
d is connected via the metal terminal piece 2 to an inner surface electrode 5a of an electrode 5 formed on the inner and outer surfaces of the case 3 so as to be connected through an opening 3a.

The piezoelectric resonator configured in this manner is preferably attached by placing the outer electrode 5b of the electrode 5 on the wiring of the printed circuit board and performing soldering.

Note that the connection between the metal terminal piece 2 and the terminal electrodes 1c and ld and the connection between the metal terminal piece 2 and the inner surface electrode 5a may be made by simply bringing them into contact as in this example, but if there is a conductive In this way, even if there are dimensional errors in the case or the piezoelectric element, the connection can be made without any problem. However, the amount of paste is preferably small to prevent short circuits.

Furthermore, in consideration of dimensional errors, it is preferable that the metal terminal piece 2 is provided with elastic protrusions 2g on both sides as shown in FIG. 3 on the outer surface 2f. The protrusion 2g (the one in the center of the figure) facing toward the outside is easily connected to the terminal electrodes 1c, ld, while the protrusion 2g (the one on the side of the figure) facing outward is easily connected to the inner electrode 5a. In this example, the protrusion 2g is on the outer surface 2f.
Although it is formed by making a cut in a U-shape and bending it, it may also be formed by attaching it by welding or the like.The protrusion 2g is formed on the outside of the outer surface 2r. They may be formed so as to face only inward, or only inward, and there are no limitations on their number or position.

FIG. 4 is an exploded perspective view showing another embodiment of the present invention.

The metal terminal piece 12 shown in this example is centered in the height direction of the case 13, and has a J-shape but has a U-shaped piezoelectric element fixing part 12a on the short side.
is inserted into the case 13 from below with both ends of the same piezoelectric element l inserted into the fixing part 12a, and the fifth
As shown in the figure, the tip of the long side of the metal terminal piece 12 protruding above the case 13 is bent. The upper bent portion 12b and the lower bent portion 12c form the case 13.
A metal terminal piece 12 is fixed to the metal terminal piece 12, and the piezoelectric element 1 is further fixed to the fixing portion 12a of the metal terminal piece 12.

Therefore, the U-shaped fixing portion 1 of the metal terminal piece 12
By designing the center of 2a to match the center of the height inside the case 13, the piezoelectric element 1 fixed to the metal terminal piece 12 is automatically centered without having to determine its height. be able to.

After this state is reached, the case 14 is attached to the lower opening 13a of the case 13, and the inside of the case is sealed.

With such a configuration, the terminal electrodes 1c and ld can be electrically taken out of the case via the metal terminal piece 12, and forming the electrode 5 on the case 13 can be omitted. It has the advantage of being able to

In this example, the width of the metal terminal piece 12 and the inner dimension in the width direction of the case 13 are almost equal. Therefore, when the metal terminal piece 12 is inserted into the case 13, the metal terminal piece 12 is inserted into the case 13. Since the piece 12 is centered in the width direction, positioning in the lateral direction is not considered.
However, if the width of the metal terminal piece 12 is much smaller than the inner dimension in the width direction of the case 13, the metal terminal piece 12 may be provided with protruding portions 2b, 2 as described above that can be centered laterally.
d (see FIG. 1).

FIG. 6 is a sectional view showing still another embodiment of the present invention.

In this example, the thickness of the terminal electrodes 1c and ld of the piezoelectric element 1 is increased over the whole, for example, the thickness of the terminal electrodes 1c and ld of the piezoelectric element 1 is increased.
The dimension t1 in the thickness direction is equal to the inner dimension (height direction) of the case 3, and the thickness of the parts protruding in the thickness direction on both sides of the piezoelectric element 1 is the same, and the length of the piezoelectric element 1 is The dimension t2 in the direction is formed to be equal to the inner dimension (length direction) of the case 3.

Therefore, when such a piezoelectric element 1 is placed in a case 3 in which electrodes 5 are formed on both inner corner surfaces, it is naturally centered and electrically connected to the inner product electrode 5a of the electrode 5.

Note that connecting by making the terminal electrodes 1c and ld thicker as described above is not limited to this example, but can also be applied to the cases shown in Figure 1 and Figure 4, which will further improve the connection with the one-sided electrode. It's easy to do.

Further, in each of the above embodiments, a case with a short height (1) and a long width (W) is used, but a case with a long height (W) and a short width (W) may also be used as shown in FIG. .

Furthermore, although each of the above embodiments is applied to a piezoelectric resonator,
It is a theory that the present invention is not limited to this, but can be applied to general piezoelectric components using single crystals or piezoelectric substrates.

As described in detail above, in the case of the present invention, the case is formed in the shape of a rectangular parallelepiped, so that the piezoelectric element 2 can be stored at a tilt of 4 degrees without large gap fluctuations, and therefore it can be made compact. Furthermore, since a case with only one side open can be used, the sealing performance can be improved.

In addition, by using the metal terminal piece described above, the piezoelectric element can be centered with respect to the case without the need for alignment, which makes it possible to increase mass production efficiency. When using this, not only centering but also the terminal electrode can be electrically taken out from the case via this metal terminal piece, and it is possible to omit forming a lead-out electrode in the case.

Also, if the terminal electrodes at both ends of the piezoelectric element are made thicker,
It is possible to connect to centering and inner electrodes formed on the case without using metal terminal pieces.

Furthermore, since the structure is such that there is no problem even if the conductive paste is omitted, an excellent effect can be achieved in that short circuits are less likely to occur.

[Brief explanation of drawings]

Fig. 1 is an exploded perspective view showing the case where the present invention is applied to a piezoelectric resonator, Fig. 2 is a front view thereof, Fig. 3 is a perspective view showing another metal terminal piece, and Fig. 4 is an exploded perspective view showing the case where the present invention is applied to a piezoelectric resonator. FIG. 5 is a front view thereof, FIG. 6 is a sectional view showing still another embodiment of the present invention, and FIG. 7 is another case example applicable to the present invention. FIG. 8 is an exploded perspective view showing the structure of a conventional product. 1...Piezoelectric element, la, lb-electrode, lc, ld...
・Terminal electrode, 2...Metal terminal piece, 2a-2d...Protrusion part, 2e...Inner depth, 2g...Protrusion part, 3...
・Case 4...1L5...Electrode, 12...Metal terminal piece, 12a...Fixing part for piezoelectric element, 13...Case.

Claims (2)

[Claims] (1) A piezoelectric component in which a plate-shaped piezoelectric element is housed in a rectangular parallelepiped-shaped case, in which terminal electrodes are formed at both ends of the piezoelectric element, and conductive material is formed in the gap between the terminal electrode and the inner surface of the case. A metal terminal piece is inserted, and the metal terminal piece holds the piezoelectric element in a positioned state with respect to the case, and is formed in a state that allows electrical extraction to the outside of the case. piezoelectric components. (2) A piezoelectric component in which a plate-shaped piezoelectric element is housed in a rectangular parallelepiped-shaped case, and thick terminal electrodes are formed at both ends of the piezoelectric element,
A piezoelectric component characterized in that the thick terminal electrode is formed so as to hold the piezoelectric element in a positioned state with respect to the case and to have conduction with an external connection pattern provided on the case.