JPH088688A - Multi-stage surface mount piezoelectric filter - Google Patents

Abstract

(57) [Abstract] [Purpose] To obtain a multi-stage connection surface mount type piezoelectric filter in which the electrical characteristics can be easily combined and the area of the entire filter component is reduced. Also, the purpose is to prevent electromagnetic coupling that occurs between the input and output terminals of the piezoelectric filter and to obtain desired electrical characteristics. [Constitution] The storage case 2 is made of ceramics or a resin material, and the side surface of the storage case Convex connection part 2 formed on
4 and 26 and concave connecting portions 25 and 27. The crystal filter 1 is stored in the storage case 2, and the input / output terminal 11, the ground terminal 12, and the input / output terminal 13 are fixed to the terminal fixing plates 31, 32, 33, respectively.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piezoelectric filter such as a crystal filter used in communication equipment and the like, and more particularly to a multistage connection surface mount type piezoelectric filter which is compatible with surface mounting and facilitates multistage connection. .

[0002]

2. Description of the Related Art In a piezoelectric filter such as a crystal filter, a crystal filter may be connected in multiple stages for the purpose of sharpening a pass band characteristic gradient, improving a guaranteed attenuation amount, and removing spurious. FIG. 9 shows a structure in which two crystal filters are connected in multiple stages to achieve the above-mentioned object. In FIG. 9, a crystal filter F1,
F2 is connected in multiple stages through necessary circuit components such as a capacitor and a resistor. With the recent miniaturization of electronic devices, the crystal filter used here is required to be small and to be mounted on a printed wiring board at a high density on its surface. As an example of surface mounting a crystal filter, there is a structure as shown in Japanese Utility Model Laid-Open No. 4-15312.

[0003]

Generally, when connecting crystal filters in multiple stages, a proper combination is required according to the required electrical characteristics, and if the combinations are different, the characteristics deteriorate. Was there. Conventionally, even if this appropriate combination was obtained, it was necessary to store this combination in some form until it was connected to the printed wiring board, which was troublesome to manage. Further, since a plurality of crystal filters are mounted on the printed circuit board by soldering or the like, there is a problem that the area constituting the filter becomes large as a whole. Also,
Electromagnetic coupling due to a direct wave may occur between terminals of one piezoelectric filter or between terminals of another piezoelectric filter adjacent thereto, and desired electrical characteristics cannot be obtained in terms of guaranteed attenuation and the like. There were cases.

The present invention has been made to solve the above problems, and in obtaining a multi-stage connection surface mount type piezoelectric filter, the electrical characteristics can be easily combined, and the area of the filter constituent portion as a whole can be reduced. It is intended to obtain a multi-stage connection surface mount type piezoelectric filter.
Another object is to prevent electromagnetic coupling that occurs between the input and output terminals of the piezoelectric filter and obtain desired electrical characteristics.

[0005]

In order to solve the above-mentioned problems, a multi-stage connection surface mount type piezoelectric filter according to the present invention is a piezoelectric filter main body and a piezoelectric element in which an input / output terminal and a ground terminal are extended from the piezoelectric filter main body. A multi-stage connection surface mounting type filter comprising a filter and a plurality of surface mounting type piezoelectric filters, each accommodating the piezoelectric filter, the accommodating case having a recess having at least one surface opened, the accommodating case comprising: An electrode lead-out mechanism that is electrically connected to the lead terminal and leads the lead terminal out of the housing case is provided, and at least one side surface of the housing case is connected to one or more other surface-mounted piezoelectric filters by engagement. It is characterized by having a connecting portion.

Further, in the multi-stage connection surface mount type piezoelectric filter according to claim 1, a conductive mechanism is provided near the periphery of at least one terminal of the piezoelectric filter, and the conductive mechanism is conductively connected to the ground terminal. It is characterized by Examples of the conductive mechanism include, but are not limited to, a metal plate, a metal film formed on a storage case, or a combination thereof.

[0007]

According to the present invention, the piezoelectric filter having the terminals for input / output and the like is housed in the housing case, and the terminals are electrically led out of the housing case. A surface-mounted piezoelectric filter can be obtained simply by installing the filter. In addition, a suitable combination of multi-stage connections is made according to the required electrical characteristics.When this suitable combination is obtained, other surface mount filters can be easily installed by the connecting part provided on the side of the storage case. It can be integrated, and it is extremely easy to store the combination of the multi-stage connection of surface mount filters. Also, it is not confused with other surface mount piezoelectric filters.

According to the invention described in claim 2, in the multi-stage connection surface mount type piezoelectric filter described above,
Since the conductive mechanism is provided at least between the input / output terminals of the piezoelectric filter, it is possible to absorb the direct wave generated between the input / output terminals.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described with reference to the drawings, taking a crystal filter as an example. 1 is an exploded perspective view showing a first embodiment of the present invention, FIG. 2 is a perspective view showing a configuration in which the respective constituent parts of FIG. 1 are connected, and FIG. 3 is a front view of FIG.
FIG. 4 is a plan view showing a state in which two surface mount piezoelectric filters having the configuration of FIG. 2 are connected. The crystal filter 1 includes a crystal filter body 10 and an input / output terminal 1 extending from the body.
1, 13 and the ground terminal 12. Although not shown, the crystal filter body 10 has a quartz plate having two input / output electrodes on the front surface and a common electrode on the back surface installed on the base and is hermetically sealed with a metallic cap. . The base is provided with a flange used for hermetically sealing with the cap. Each of the electrodes is led to the outside by each of the terminals. The storage case 2 is made of ceramics or a resin material, and has a concave portion 20 for storing the crystal filter and terminal mounting portions 21, 22, 23 for mounting and fixing the terminals.
And a metal terminal fixing plate 3 fixed to this terminal installation portion
1, 32, 33, external lead-out electrodes 34, 35, 36 electrically connected to the terminal fixing plate independently of each other, and convex connecting portions 24, 26 and concave connecting portions formed on the side surface of the storage case. It is composed of parts 25 and 27. Terminal fixing plates 31, 32,
33 is embedded and fixed in a storage case, and has a shape for fixing each terminal with a clip as shown in FIG. In addition, each connecting portion has a shape in which the convex and concave portions slightly expand toward the tip thereof, and is configured so that the concave and convex portion that engages during connection does not come off.

As shown in FIG. 2, the crystal filter 1 is housed in the housing case 2, and the input / output terminal 11, the ground terminal 12, and the input / output terminal 13 are fixed to the terminal fixing plates 31, 32, 33, respectively. . If desired, this fixing portion may be fixed with a conductive bonding material. Although not shown, the opening of the recess of the storage case may be sealed with a cover plate if necessary.

In such a surface mount type crystal filter, for example, as shown in FIG. 2, the input / output terminals 11 are arranged.
It is specified that the position with is on the side surface side where the convex connecting portion 24 exists. The convex connecting portion 24 serves as a marker to clearly indicate the specified input / output terminal side. As shown in FIG. 4, when connecting the storage cases 2 and 2 ′ to the surface-mount type crystal filter whose terminal positions are clearly defined as described above, the convex connecting portion 24 ′ is engaged with the concave connecting portion 27. With
By engaging the convex connecting portion 26 with the concave connecting portion 25 ', both are connected.

As shown in FIG. 5, wiring is provided inside or around the storage case with the electrode film E, and when the storage case 2 and the storage case 2'are connected, a proper combination is prepared in advance. The input / output terminal 13 and the input / output terminal 11 'may be electrically connected. With such a configuration, it is possible to partially save the time and effort for making an electrical connection outside the storage case.

A second embodiment of the present invention will be described with reference to the drawings. FIG. 6 is a perspective view showing a second embodiment of the present invention. The same components as those in the first embodiment will be described using the same numbers, and description thereof will be partially omitted. The storage case 2 storing the crystal filter 1 is provided with a terminal fixing plate and external lead-out electrodes, and shield electrodes 41 and 42 are provided on both inner walls of the terminal installation portion 22 for installing the ground terminal and on the upper surface adjacent thereto. Has been formed. The shield electrodes 41 and 42 are electrically connected to each other and are also connected to the external lead-out electrode 35 for grounding. This shield electrode can absorb a direct wave generated between the input / output terminals or the terminals of another crystal filter, and can improve the electrical characteristics (eg, guaranteed attenuation amount) of the crystal filter.

A third embodiment of the present invention will be described with reference to the drawings. FIG. 7 is a perspective view showing a third embodiment. The same components as those in the first embodiment will be described using the same numbers, and description thereof will be partially omitted.
The storage case 2 in which the crystal filter 1 is stored is provided with a terminal fixing plate and external lead-out electrodes, and a fixed terminal plate 3
2 is integrally provided with a shield metal plate 32a extending along the inner wall of the terminal installation portion. Of course, the fixed terminal plate 32 is connected to the external lead-out electrode 35 for grounding, and this shield metal plate 32a absorbs the direct wave generated between the input / output terminals or the terminals of other crystal filters, and the crystal It is possible to improve the electrical characteristics as a filter (for example, the guaranteed attenuation amount).

In the second and third embodiments, the shield electrode or the shield metal plate is not limited to being formed only around the ground terminal, but around the input / output terminal or the storage case. You may expand and form in another part. However, in either case, it must be electrically connected to the ground terminal. Moreover, you may use a shield electrode and a shield metal plate together. In this case, there is an effect of enhancing the electromagnetic shield effect.

A fourth embodiment of the present invention will be described with reference to the drawings. FIG. 8 is a plan view showing the fourth embodiment. The same components as those in the first embodiment will be described using the same numbers, and description thereof will be partially omitted.
The storage case 5 is formed with two recesses 50A and 50B, the outer periphery of which is provided with connecting portions 51, 52, 53 and 54, and the crystal filters 1 and 1 ', respectively.
Is stored. Terminal installation parts 61, 62, 63, 6
A metal film is formed on 4, 65, 66, and the input / output terminal 11, the ground terminal 12, and the input / output terminal 1 are respectively formed.
3, the input / output terminal 11 ', the ground terminal 12', and the input / output terminal 13 'are installed and conductively joined by the conductive joining material S1. The input / output terminal 13 of the crystal filter 1 and the input / output terminal 11 ′ of the crystal filter 1 ′ are wired so as to be electrically joined inside the housing case 5, and the ground terminal is also commonly connected. This saves the trouble of electrical connection outside the storage case. When the multi-stage connection of the surface mount type crystal filters in which two such crystal filters are accommodated in one case is further connected, another pair of surface mount type crystal filters are connected by the connecting portion.
The shape of the connecting portion is not limited to the shape of the above embodiment, and may be any configuration that mechanically connects the surface-mounted piezoelectric filter.

[0017]

According to the present invention, since the piezoelectric filter having the terminals for input / output and the like is housed in the housing case and the terminals are led out of the housing case, the piezoelectric filter is provided in the recess of the housing case. A surface-mounted piezoelectric filter can be obtained simply by installing. Also, an appropriate combination of multi-stage connection is made according to the required electrical characteristics,
When this appropriate combination is obtained, the connection part provided on the side surface of the storage case makes it easy to integrate other surface mount filters, and it is extremely possible to save the combination of the multi-stage connection of surface mount filters. It is not easily confused with other surface-mounted piezoelectric filters.

According to the invention described in claim 2, in the multi-stage connection surface mount type piezoelectric filter described above,
Since the conductive mechanism is provided at least between the input / output terminals of the piezoelectric filter, it is possible to absorb the direct wave generated between the input / output terminals. Therefore, it is possible to prevent electromagnetic coupling and improve electrical characteristics such as guaranteed attenuation.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing a first embodiment of the present invention.

FIG. 2 is a perspective view showing a first embodiment of the present invention.

FIG. 3 is a front view showing the first embodiment of the present invention.

FIG. 4 is a plan view showing a first embodiment of the present invention.

FIG. 5 is a plan view showing another example of the first embodiment of the present invention.

FIG. 6 is a perspective view showing a second embodiment of the present invention.

FIG. 7 is a perspective view showing a third embodiment of the present invention.

FIG. 8 is a perspective view showing a fourth embodiment of the present invention.

FIG. 9 is a diagram showing a conventional example of the present invention.

[Explanation of symbols]

 1 Crystal Filter (Piezoelectric Filter) 2 Storage Case 20 Recesses 21, 22, 23 Terminal Installation Part 31, 32, 33 Terminal Fixing Plate 34, 35, 36 External Lead-out Electrode

Claims (2)

[Claims] 1. A surface mount comprising a piezoelectric filter main body, a piezoelectric filter having an input / output terminal and an earth terminal extended from the piezoelectric filter main body, and a storage case for accommodating the piezoelectric filter, the storage case having a recess at least one surface of which is open. A multi-stage connection surface mounting type filter formed by connecting a plurality of piezoelectric piezoelectric filters, wherein the storage case is provided with an electrode lead-out mechanism that is electrically connected to the lead terminals and leads out the lead terminal to the outside of the storage case. A multi-stage connection surface-mount type piezoelectric filter, wherein at least one side surface of the housing case has a connecting portion that is connected to one or more other surface-mounting piezoelectric filters by engagement. 2. A conductive mechanism is provided between at least input / output terminals of the piezoelectric filter, and the conductive mechanism is conductively connected to the ground terminal.
A multi-stage connection surface mount type piezoelectric filter as described in the item.