JP4057366B2 - Piezoelectric element container and crystal resonator using the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a piezoelectric element container and a crystal resonator using the same, and particularly to a piezoelectric element container that promotes a reduction in height.
[0002]
[Prior art]
(Background of the Invention) Piezoelectric elements, particularly crystal resonators, are widely used in oscillators and filters as frequency control elements. In recent years, downsizing and weight reduction have been established, and further reduction in height has been progressing. The presence of the piezoelectric element container 1 is indispensable for reducing the height.
[0003]
(Example of Prior Art) FIG. 3 is a view of a quartz crystal resonator including a container for a piezoelectric element for explaining one conventional example, FIG. 3 (a) is a sectional view, FIG. 3 (b) is a plan view of a ceramic layer, FIG. 2C is a rear view.
The crystal resonator is formed by sealing and enclosing a crystal piece 2 in a piezoelectric element container 1. The piezoelectric element container 1 includes a container body 3 and a metal cover 4. The container body 3 includes a concave ceramic layer 5 having a laminated structure and a metal ring 6 provided on the upper surface. The ceramic layer 5 is formed by laminating a bottom wall layer 7 and a frame wall layer 8. And it has a pair of crystal terminal 9 as a junction terminal on both sides of the one end part on the inner bottom face of the bottom wall layer 7. Further, a pillow portion 10 made of a dielectric film is formed on the other end portion by printing or the like. Here, the dielectric film is made of the same material as the ceramic layer 5. The pair of crystal terminals 9 are connected to mounting terminals 11 (ab) provided on one outer surface in the diagonal direction through the laminated surface.
[0004]
Further, the mounting terminals 11 (cd) provided on the other diagonal outer surface are connected to the conductive film 12 provided on the upper surface of the frame wall layer 8 by the electrode through hole (via hole) 13. These are integrally formed by firing. A metal ring 6 is joined to the upper surface of the frame wall layer 8 by silver solder and is electrically connected to the conductive film 12. This is formed after firing.
[0005]
The crystal piece 2 is made of AT cut, has excitation electrodes (not shown) on both main surfaces, and extends extraction electrodes on both sides of one end. Both ends of one end of the crystal piece 2 from which the extraction electrode extends are fixed to the crystal terminal 9 of the container body 3 by a conductive adhesive 14 and are electrically and mechanically connected. In this case, the other end portion of the crystal piece 2 is placed on the pillow portion 10. For example, the laser electrode is irradiated with a laser beam to adjust the vibration frequency, the metal cover 4 is joined to the metal ring 6 by seam welding, and the crystal piece 2 is hermetically sealed.
[0006]
[Problems to be solved by the invention]
(Problem of the prior art) However, in the crystal resonator having the above-described configuration, the container body 3 is provided with the metal ring 6 on the frame wall layer having a laminated structure, and the bottom wall layer 7, the frame wall layer 8, and the metal ring 6 are provided. A three-layer structure is adopted. Therefore, there is a problem that the height dimension becomes large and it is difficult to reduce the height. And since it was a laminated structure, there existed a problem which became expensive. The sum of the thickness of the frame wall layer 8 and the metal ring 6 may be larger than the height of the crystal piece 2, but the frame wall and the metal ring 6 inevitably require a minimum thickness, so It becomes larger than the height of 2.
[0007]
From this, it has been considered that the container body 3 is formed of the bottom wall layer 7 and the metal ring 6 (refer to JP 2000-138532 A). However, in this case, in order to connect the crystal terminal 9 and the mounting terminal 11 to increase the sealing degree, the bottom wall layer 7 has a laminated structure with the electrode leading out in a crank shape. Therefore, since the bottom wall layer 7 has a two-layer structure, it is difficult to reduce the height and the cost (reduction in cost).
[0008]
(Object of the invention) An object of the present invention is to provide a container for a piezoelectric element suitable for a reduction in height and a crystal resonator using the same.
[0009]
[Means for Solving the Problems]
According to the present invention (Claim 1), the ceramic layer of the container body is a single layer, and the junction terminal and the mounting terminal are provided on the inner bottom surface and the outer surface of the ceramic layer and on the ceramic layer in the metal ring. , electrically connected via adjacent electrodes through holes (via holes) in the wiring passage end portion, structure provided with the dielectric film on at least one major surface of the electrode through-holes in the hand wiring passage end portion and the electrode through-holes on And As a result, the container body is constituted by a single ceramic layer and a metal ring, thereby achieving a low profile. And since a dielectric film is provided in an electrode through-hole, sealing is ensured.
[0010]
According to the second aspect of the present invention, the dielectric film is provided on the other end side, so that it can be applied as a crystal piece pillow table on which the other end portion of the crystal piece is placed. According to the third aspect of the present invention, since the crystal resonator is configured using the piezoelectric element container, a crystal resonator achieving a low profile can be obtained. An embodiment of the present invention will be described below.
[0011]
【Example】
FIG. 1 is a diagram of a crystal resonator including a piezoelectric element container according to an embodiment of the present invention. FIG. 1 (a) is a sectional view, FIG. 1 (b) is a plan view of a ceramic layer, and FIG. ) Is a back view. In addition, the same number is attached | subjected to the same part as a prior art example, and the description is simplified or abbreviate | omitted.
The crystal resonator is formed by sealing and enclosing a crystal piece 2 in a piezoelectric element container 1 formed by seam welding a container body 3 and a metal cover 4 as described above. The container body 3 here includes a ceramic layer 5 and a metal ring 6. The ceramic layer 5 is a single layer, and a conductive film 12 is formed on the outer periphery. A pair of crystal terminals 9 are formed on one end side of the inner bottom surface, and a via hole 15 is formed on the other end side. The pair of crystal terminals 9 and the via holes 15 are connected by a wiring path. Then, a dielectric film as the pillow 10 is formed on the via hole 15 on the inner bottom surface by printing. Again, the dielectric film is the same material as the ceramic layer 5.
[0012]
Mounting terminals 11 (abcd) are formed at four corners on the outer surface of the ceramic layer 5, and the mounting terminals 11 (cd) on one end side are connected to the conductive film 12 by side electrodes obtained by dividing electrode through holes (not shown). Further, the mounting terminal 11 (ab) on the other end side is electrically connected to the crystal terminal 9 through the via hole 15. These are integrally formed by firing. Then, the metal ring 6 is joined to the conductive film 12 by silver solder to form the container body 3.
[0013]
Then, the other end portion of the crystal piece 2 is placed on the pillow table 10, and both ends of the end portion of the crystal piece 2 from which the extraction electrode extends are electrically and mechanically applied to the pair of crystal terminals 9 by the conductive adhesive 14. Connect. Further, after adjusting the vibration frequency, the metal cover 4 is joined to the metal ring 6 by seam welding, and the crystal piece 2 is hermetically sealed.
[0014]
With such a configuration, the container body 3 is formed from the ceramic layer 5 and the metal ring 6 which are formed as a single layer. Therefore, the crystal piece 2 can be formed by making only the thickness of the metal ring 6 equal to or greater than the height of the crystal piece 2. Space to be accommodated can be secured. Therefore, the minimum thickness can be set to promote downsizing. And since the via hole 15 connected to the mounting terminal 11 is sealed by the pillow table 10, the degree of sealing is ensured.
[0015]
[Other matters]
In the above embodiment, the pair of crystal terminals 9 are extended by the via holes 15 provided in the lower part of the pillow 10 on the other end side and connected to the mounting terminals 11 on the other end side. If standardized, etc., the following may be used. That is, as shown in FIG. 2, one of the crystal terminals 9 is connected to one mounting terminal (not shown) in the diagonal direction by a via hole 15 provided in the lower part of the pillow table 10. The other side of the crystal terminal 9 is connected to the other mounting terminal (not shown) in the diagonal direction by a via hole 15 provided in the vicinity. Then, the via hole 15 is sealed by printing the dielectric film 16 having a thickness smaller than that of the pillow table 10.
[0016]
In addition, via holes may be provided at two locations separate from the pillow table 10 and connected to an arbitrary pair of mounting terminals, and a dielectric film smaller than the thickness of the pillow table 10 may be provided and sealed. The via hole is sealed from the inner bottom surface side of the ceramic layer 5 by the pillow 10 or a dielectric film having a smaller thickness, but may be provided and sealed on the outer surface on the other main surface side. Moreover, you may provide only in an outer surface and the point should just provide in at least any one main surface. In addition, when forming in an outer surface, it is made smaller than the thickness of the mounting terminal 11. FIG.
[0017]
Although described as a quartz resonator, the present invention can also be applied to a filter container including a surface acoustic wave that houses and configures a piezoelectric element. Furthermore, the present invention can be applied to a crystal oscillator in which a concave portion is formed on the back surface of the container body 3 and an IC chip is accommodated, and appropriate changes can be made without departing from the spirit of the crystal oscillator.
[0018]
【The invention's effect】
According to the present invention (Claim 1), the ceramic layer of the container body is a single layer, and the junction terminal and the mounting terminal are provided on the inner bottom surface and the outer surface of the ceramic layer and on the ceramic layer in the metal ring. , electrically connected via adjacent electrodes through holes in the wiring passage end portion, it is provided with the dielectric film on at least one major surface in hand wiring passage end portion and the electrode through-hole electrode on the through-hole, low Achieving profile and ensuring sealing.
[Brief description of the drawings]
FIGS. 1A and 1B are diagrams of a crystal resonator illustrating an embodiment of the present invention, in which FIG. 1A is a cross-sectional view, FIG. 1B is a plan view of a ceramic layer, and FIG. FIG.
FIG. 2 is a plan view of a ceramic layer for explaining another embodiment of the present invention.
3A and 3B are diagrams of a crystal resonator for explaining a conventional example. FIG. 3A is a cross-sectional view, FIG. 3B is a plan view of a ceramic layer, and FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Piezoelectric element container, 2 Crystal piece, 3 Container body, 4 Metal cover, 5 Ceramic layer, 6 Metal ring, 7 Bottom wall layer, 8 Frame wall layer, 9 Crystal terminal, 10 Pillow, 11 Mounting terminal, 12 Conductivity Film, 13, 15 Via hole, 14 Conductive adhesive.

Claims (3)

A ceramic layer having a bonding terminal with a piezoelectric element on the inner bottom surface and having a mounting terminal electrically connected to the bonding terminal on the outer surface, and provided on the outer circumference of the inner bottom surface of the ceramic layer to accommodate the piezoelectric element In the container for a piezoelectric element including a container body composed of a metal ring for seam welding formed with a space, the ceramic layer is a single layer, and the joining terminal and the mounting terminal are inner bottom surfaces of the ceramic layer. and provided with the wiring passage provided on the outer surface of the ceramic layer in the metal ring, electrically connected via the electrode through-holes adjacent to the wiring passage end portion, at least one main surface in hand the wiring A container for a piezoelectric element, wherein a dielectric film is provided on a path end and the electrode through hole . The piezoelectric element container according to claim 1, wherein the joining terminals are provided as a pair on one end side of the ceramic layer, and the dielectric film is provided on the other end side of the ceramic layer. A pair of the junction terminals according to claim 2 is connected to both sides of one end portion of a crystal piece extending from an excitation electrode and an extraction electrode, and the other end portion of the crystal piece is placed on the dielectric film. Child.

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