JPH0918285A - Ladder filter - Google Patents

Abstract

PURPOSE: To provide the ladder filter whose surface mounting is adapted to a printed circuit board and to which an automatic assembling device can be applied. CONSTITUTION: In a ladder filter 10, laminated bodies 3a and 3b consisting of piezoelectric resonators 31a to 33a and 31b to 33b and terminal assemblies 24, 34, 35, 37, 39, 51, and 71 are arranged in the storage body consisting of a lower case 1 like a box, where input/output terminal electrodes 5 and 6 and an grounding terminal electrode 7 are integrally formed and a cavity part 11 is provided, and an upper case 2 concealing the cavity part 11. Laminated bodies 3a and 3b are put one over the other as planes from the aperture on the upper face side of the cavity part 11. Terminal electrodes and terminal assemblies are connected on the outside of the cavity part 11, and these connection parts are covered with resin.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is a ladder type filter suitable for surface mounting on a printed wiring board and capable of being automatically assembled, in which a laminated body is horizontally stacked and arranged from a piezoelectric element and a terminal plate. And a ladder type filter.

[0002]

2. Description of the Related Art Conventionally, a ladder-type filter with a lead has a laminated body in which a piezoelectric resonance element having vibrating electrodes formed on both front and back surfaces and a plurality of terminal plates contacting the vibrating electrodes are alternately laminated on one surface. It was arranged in a case having an opening.

Piezoelectric resonance elements constituting a laminated body are composed of a plurality of piezoelectric resonance elements (series piezoelectric elements) forming a series circuit section of a ladder type circuit and a plurality of piezoelectric resonance elements (series parallel circuit section of a ladder type circuit). Parallel piezoelectric elements), and a terminal plate having a predetermined structure is used so that these have a ladder-type circuit configuration. It should be noted that the lead portions extend to the terminal plates that serve as the input / output and the ground potential, respectively.

The housing structure of the ladder type filter with leads has been arranged in parallel by inserting and arranging from the end face direction of each piezoelectric element and the terminal plate so that the lead portion extends from the opening of one surface. Then, a sealing member such as paper is placed in the opening, and the sealing resin is filled and cured.

In a surface-mounting type ladder filter using one side surface of the above-mentioned case as a mounting surface (bottom surface) of a printed wiring board, a lead portion extended from an opening located in a side surface portion is bent, It was designed to extend to the bottom of the case.

In any of the structures, it is necessary to insert and arrange a laminated body composed of a series piezoelectric element, a parallel piezoelectric element, and a terminal plate from the opening of the case from the end face direction of each piezoelectric element and the terminal plate. The placement process was very difficult.

Further, since the lead portion extending from the opening is bent to form a ladder filter that can be surface-mounted, the bending state may be different between a plurality of lead portions, and the lead portion may be different. The height of the mounting part varied due to the spring back, etc., and it was not possible to surface-mount it on the printed wiring board in a stable state.

With respect to the above-mentioned arranging step, a laminated body composed of a series piezoelectric element, a parallel piezoelectric element, and a terminal plate is divided into two sets, and the two laminated bodies are placed flat on the opening of the case. There was a ladder type filter with a structure
-134344).

In this ladder type filter, it is composed of a lower case body and a lid body, and the laminated body is laminated and placed from an opening located on the upper surface of the lower case.

[0010]

[Problems to be Solved by the Invention]
The ladder type filter described in No. 134334 is not a surface mount type but a ladder type filter with leads,
The lead portion extending from the predetermined terminal plate forming the laminated body extends through the bottom surface of the lower case to the outside. Moreover, in the case, since the terminal plate placed two-dimensionally and the lead portion extending from the bottom surface of the case are orthogonal to each other, it is necessary to perform bending processing near the boundary between the terminal plate and the lead portion. However, the contact state between the terminal plate and the piezoelectric element often changes due to stress during bending of the lead portion, and stable characteristics cannot be derived.

Also in the stacking / mounting, since the piezoelectric element and the terminal plate are arranged so as to overlap each other in plan view from the opening on the upper surface side of the case, it seems that the arrangement process becomes easy, When arranging the formed terminal plate, it is necessary to insert the terminal plate into the through hole on the bottom surface of the case, which makes the arrangement process difficult.

Further, the relationship between the lower case body and the lid body is simply arranged so as to cover the lower case body, and the airtightness of the gap between the lower case body and the lid body is taken into consideration. Absent.

The present invention has been devised in view of the above-mentioned problems, and an object thereof is a surface-mounting ladder type in which a laminated body including a piezoelectric element and a terminal plate can be easily arranged in a case. It provides a filter.

Still another object of the present invention is to provide a surface-mounting ladder type filter which can stably and reliably connect the laminated body and the terminal electrode.

Still another object of the present invention is to provide a surface-mounting ladder type filter having improved connection reliability at the above-mentioned connecting portion.

Still another object of the present invention is to provide a surface-mounting ladder type filter capable of reliably hermetically sealing the inside of the case in which the laminated body is housed.

Further, another object of the present invention is to provide a surface mount type ladder type filter which can simplify the structure of a laminated body composed of a piezoelectric element and a terminal plate.

[0018]

According to a first aspect of the present invention, there is provided a laminated body comprising a plurality of piezoelectric resonators and a plurality of terminal plates, on which an input / output terminal electrode and an earth terminal electrode are integrally formed, and which is provided on the upper surface. A ladder-type filter in which each piezoelectric resonator and a terminal plate are arranged horizontally in a housing body that includes a housing-shaped lower case in which a cavity portion having an opening is formed and an upper case that conceals the cavity portion. Is.

According to a second invention, in the ladder type filter of the first invention, a notch is formed on a side wall of the cavity of the lower case, and one of the terminal plates is provided through the notch. In the ladder-type filter, a terminal plate connecting portion extending from the terminal electrode is led out to the outside of the cavity portion and connected to a terminal electrode connecting portion extending from the terminal electrode on the outside of the cavity portion.

A third aspect of the present invention is the ladder type filter of the second aspect of the present invention, in which the upper case has a side wall facing the outer side wall of the cavity, and the terminal electrode is connected to the side wall. A ladder-type filter in which a cutout portion is formed to expose a connection portion between the connection portion and the connection portion of the terminal plate, and the cutout portion is filled with an insulating sealing resin.

A fourth aspect of the present invention is the ladder type filter of the third aspect of the present invention, in which a ridge is formed on the outer surface of the side wall of the cavity of the lower case and / or the inner surface of the side wall of the upper case.
A ladder-type filter in which a gap is formed between the outer surface of the side wall of the cavity portion and the inner surface of the side wall of the upper case by the protrusion, and the gap is filled with an insulating sealing resin.

A fifth aspect of the present invention is the ladder type filter of the first aspect of the invention, wherein a part of the upper case and / or the lower casing case is brought into contact with the piezoelectric resonator constituting the laminated body,
Moreover, it is a ladder type filter in which a terminal plate connected to one of the terminal electrodes is embedded.

[0023]

According to the first aspect of the present invention, the lower case is formed with the cavity portion having the upper surface opened, and the piezoelectric element and the terminal plate constituting the laminated body are formed from the opening of the upper surface of the cavity portion. Since they can be sequentially stacked horizontally, the stacking / arranging process becomes very simple and can be easily carried out by an automatic assembling apparatus. Further, since the input / output / ground terminal electrodes connected to the predetermined terminal board are integrally formed in the lower case, the processing / forming state of each terminal electrode can be made uniform, which enables the printed wiring board and The connection states can be made the same, and the surface mounting can be performed reliably and stably.

At the same time, since each terminal electrode is integrally formed in the lower case and it is not necessary to form a through hole or the like through which the lead portion penetrates on the bottom surface of the case as in the conventional case, the laminated body is arranged. The inside of the cavity can be hermetically sealed.

According to the second aspect of the present invention, the side wall of the cavity portion is formed with a notch formed in a part of the predetermined terminal plate to extend the connecting portion of the terminal plate, and the predetermined terminal electrode. A part of the terminal electrode extending from the vicinity of the cutout portion to the vicinity of the cutout portion is arranged, and the connection portion of the terminal plate and the connection portion of the terminal plate are joined to each other outside the cutout portion. Therefore, it is not necessary to make a connection when superposing and arranging the constituent members constituting the laminated body in the cavity portion, and particularly, the connection between the terminal plate and the terminal electrode can be performed outside the cavity portion. Therefore, both steps of stacking the laminate and connecting the terminal plate and the terminal electrode are facilitated, and the terminal plate and the terminal electrode can be stably and reliably connected.

According to the third aspect of the present invention, the upper case is provided with a cutout portion that exposes a connection portion between the terminal electrode connection portion and the terminal plate connection portion, and the cutout portion is insulated. Since the resin is filled with a conductive sealing resin, the connection step described above can be performed by any connection method even after attaching the upper case.
This can be performed reliably and easily, and since the insulating sealing resin with which the cutout portion is filled completely covers the connection portion, the connection reliability is further improved.

According to the fourth aspect of the present invention, the protrusion is formed on the contact surface of either the outer surface of the side wall of the cavity portion of the lower case or the inner surface of the side wall of the upper case, and the side wall of the storage cavity portion is formed. Since a gap is formed between the upper case and the side wall of the upper case, and the gap is filled with the insulating sealing resin, the airtight sealing property at the contact portion between the lower case and the upper case is improved, and as a result, ,
It is possible to hermetically seal the inside of the cavity portion in which the laminated body is arranged.

According to a fifth invention, the upper case and / or
Alternatively, since a terminal plate that is in contact with the piezoelectric resonance element that constitutes the laminate and that is connected to the terminal electrode is embedded in a part of the lower case, the terminal plate that should originally be part of the laminate is It is omitted, and the number of members to be laminated in the laminated body is substantially reduced, and the laminating / arranging process is simplified. In addition, since the thickness of the laminated body is reduced, a low profile ladder type filter is achieved. At the same time, impact resistance is improved because the metal member of the case is embedded.

[0029]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The ladder type filter of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is an external perspective view of a ladder type filter according to the present invention, FIG. 2 is a sectional view taken along line XX in FIG. 1, and FIG. 3 is a sectional view taken along line YY in FIG. And FIG. 4 is FIG.
5 is a sectional view taken along the line Z-Z, FIG. 5 is an exploded perspective view, and FIG. 6 is an equivalent circuit diagram of a ladder type filter. In the embodiment, the first laminated body including the three piezoelectric resonance elements (hereinafter referred to as series piezoelectric elements) forming the series circuit section of the ladder type circuit and the three parallel circuit sections of the ladder type circuit are formed. Description will be made using a surface mount ladder type filter having two sets of laminated bodies including a second laminated body including a piezoelectric resonance element (hereinafter, referred to as a parallel piezoelectric element) and six elements.

As shown in FIGS. 1 to 3, the ladder type filter 10 includes a lower case 1 and an upper case 2 which form a container.
And a laminated body 3a of serial circuit constituent members in which three series piezoelectric elements and terminal plates are alternately laminated, and a laminated body 3b of parallel circuit constituent members in which three parallel resonant piezoelectric elements and terminal plates are alternately laminated. , And a sealing member 4.

The lower case 1 is made of a heat-resistant insulating resin, and as shown in FIG. 7, a base 12 having substantially the same shape as that of the upper case 2 in a plan view and a base 4 provided upright on the base 12.
Cavity 11 composed of side walls 11a to 11d
It is composed of and, and is made in the shape of a box as a whole.

Side walls 11a, 1 of this cavity portion 11
Inside the 1c, the cavity portion 11 is provided with two storage portions 1
Partition parts 13a and 13b for partitioning into 11 and 112 are formed, respectively. The partition parts 13a and 13b are 2
Although it is divided into two parts, it may be a partition wall that is connected in series. In addition, the side walls 11a to 1 of the cavity portion 11
Part of 1d, for example, the outer surface of the side walls 11b and 11d,
Protrusions 14b and 14d are formed which come into contact with the actual upper case 2. Further, the side wall 11 of the cavity portion 11
Protrusions 15 are formed on the inner surface side of a to 11d to prevent the planar displacement of the stacked bodies 3a and 3b housed in the cavity 11.

Further, the input terminal electrode 5, the output terminal electrode 6, at least one ground terminal electrode 7, and in FIG. 8, one ground terminal electrode 7 and a dummy are provided on the opposing edges of the base 12 of the lower case 1. The electrode 8 and the electrode 8 are formed by integral molding of resin. The dummy terminal electrode 8 may be electrically floating or may be integrally connected to the other terminal electrodes 5, 6, 7 and the like. Here, the terminal electrodes 5 to 8 are formed so as to be exposed from the end surface of the base 12 to the back surface thereof in order to enable surface mounting on the printed wiring board.

Further, the side wall 11a of the cavity portion 11
11d is partially formed, for example, on the side wall 11a, a cutout portion 12a having a connecting portion 6a extending from the output terminal electrode 6 is formed, and on the side wall 11c, a cutting portion having a connecting portion 7a, 7b extending from the ground terminal electrode 7a. Notches 12b, 12
c are respectively formed.

The cutout 12a is a slight cutout from the upper end of the accommodating cavity 11, and the cutout 12b is an approximate amount of the thickness of the parallel piezoelectric element from the upper end of the accommodating cavity 11. The cutout amount is two elements, and the cutout portion 12c is the storage cavity portion 1.
1 is the cutout amount for one element of the thickness of the parallel resonant piezoelectric element from the upper end of 1.

On the bottom surface of the cavity portion 11,
A buried input terminal plate 51, which is electrically connected to the stacked body 3a and is integrated with the input terminal electrode 5, is buried and formed in the first housing portion 111, and the second housing portion 112 includes:
An embedded terminal plate 71 that is electrically connected to the laminated body 3b and integrated with the ground terminal electrode 7 is embedded and formed.

The upper case 2 is made of an insulating resin, as shown in FIG.
As shown in the perspective view seen from the lower surface side of the lower case 1, the top plate 21 and at least the storage cavity portion 11 are enclosed by 4
Side walls 22a to 22d.

Of the four side walls 22a to 22d, the pair of opposing side walls 22a and 22c have cutouts 23a and 23, respectively.
a, 23c, and 23c are formed respectively. In addition, between the notch portions 23a and 23a, pillar portions 25a and 25c that contact the surface of the base 12 are formed between the notch portions 23c and 23c. Further, on the upper side of the cutout portion 23c,
Projections 26b and 26c that fit into the cutouts 12b and 12c formed in the side wall 11c of the cavity 11 are formed.

On the inner surface of the top plate 21 of the upper case 2, that is, on the ceiling surface, the first storage portion 111 and the second storage portion 1 are provided.
A buried output terminal plate 24 is formed so as to extend across 12 and to be electrically connected to the stacked bodies 3a and 3b. One end of the embedded terminal plate 24 is, for example, an embedded output terminal plate connecting portion 24a extending near the cutout portion 23a.

The cavity portion 11 of the lower case body 1 described above.
The first accommodating section 111 of the above has a laminated body 3a mainly constituting a series circuit section of a ladder type circuit, and the second accommodating section 112 has a laminated body 3b mainly constituting a parallel circuit section of a ladder type circuit. Are superposed and arranged respectively.

Here, the term "superposition / arrangement" means that the piezoelectric elements and the terminal plates, which form each of the laminated bodies 3a and 3b, are laminated / arranged in a substantially horizontal state on the base 12 of the lower case 1. It means that there is.

The laminated body 3a constitutes the series circuit portion of the ladder type circuit shown in FIG. 6, and is composed of three relatively thick piezoelectric elements (series piezoelectric elements) and two common terminal plates. ing. On the embedded input terminal plate 51 of the first housing portion 111 of the lower case 1 shown in FIG. 7, the first series piezoelectric element 31a, the common terminal plate 34, and the second series piezoelectric element 32 are provided.
a, the common terminal plate 35, and the third series piezoelectric element 33a are sequentially superposed and arranged.

Furthermore, by covering the upper case 2, the third case
The embedded output terminal plate 24 is arranged on the upper surface of the serial piezoelectric element 33a.

As a result, as shown in FIG. 6, the input terminal electrode 5, the embedded input terminal plate 51, and the first series piezoelectric element 31.
a, the common terminal plate 34, the second series piezoelectric element 32a, the common terminal plate 35, the third series piezoelectric element 33a, the embedded output terminal plate 24, and the output side terminal electrode 7 are connected in series to form a ladder type circuit. The serial circuit section of is constructed.

The laminated body 3b constitutes a parallel circuit portion of the ladder type circuit shown in FIG. 6, and includes three relatively thin piezoelectric elements (parallel piezoelectric elements), two common terminal plates, and two.
It consists of one insulating spacer and two independent terminal boards. On the embedded ground terminal plate 71 of the second housing portion 112 of the lower case 1 shown in FIG. 7, the first parallel piezoelectric element 31b,
Common terminal board 34, insulating spacer 36, independent terminal board 3
7, the second parallel piezoelectric element 32b, the common terminal plate 35, the insulating spacer 38, the independent terminal plate 39, and the third parallel piezoelectric element 33b are sequentially superposed and arranged. Further, by covering the upper case 2, the embedded output terminal plate 24 is arranged on the upper surface of the third parallel piezoelectric element 33b.

In this laminated body 3b, the independent terminal board 3
A part of 7, 39 is a side wall portion 11c of the cavity portion 11.
The connection portions 37a and 39 are led out from the cutout portions 12b and 12c to the outside. The connecting portion 37a is provided with the cutout portion 1 when the independent terminal board 37 is placed at a predetermined position.
2b, the connecting portion 39a is provided with the cutout portion 1a when the independent terminal plate 39 is arranged at a predetermined position.
It is formed so as to be derived from 2c.

As a result, the connecting portion 37 of the independent terminal board 37 is
a is led out to the cutout portion 12b, and the cavity portion 1
1 is connected to the ground terminal electrode connecting portion 7a outside. In addition, the connecting portion 39a of the independent terminal board 39 has the cutout portion 12
It is led to c and is connected to the earth terminal electrode connecting portion 7b outside the cavity portion 11.

By the covering of the upper case 2, the notches 12b and 12c are fitted by the projections 26b and 26c of the upper case 2, and the connecting portion 24 of the embedded output terminal board 24 is also provided.
a is connected to the connecting portion 6a of the output terminal electrode 6 of the lower case 1.

That is, as shown in FIG. 6, the first parallel piezoelectric element is provided between the common terminal plate 34 which is also connected to the first series piezoelectric element 31a and the embedded ground terminal plate 71 which is integrated with the ground terminal electrode 7. 31b is connected.

The second parallel piezoelectric element 32b is connected between the common terminal plate 35 which is also connected to the second series piezoelectric element 32a and the independent terminal plate 37 which is connected to a part of the ground terminal electrode 7.

Further, the third parallel piezoelectric element 33b is connected between the embedded output terminal plate 24 also connected to the third series piezoelectric element 33a and the independent terminal plate 39 connected to a part of the ground terminal electrode 7. It That is, the laminated body 3b including the first to third parallel piezoelectric elements 31b to 33b constitutes the parallel circuit portion of the ladder type circuit. In the laminated body 3b, the insulating spacers 36, 38 are the common terminal plates 34, 3
5 and the independent terminal plates 37 and 39 are electrically separated,
First-stage ladder circuit, second-stage ladder circuit, and second
A short circuit is prevented between the ladder circuit of the third stage and the ladder circuit of the third stage.

Here, the series piezoelectric elements 31a to 33a and the parallel piezoelectric elements 31b to 33b are constituted by vibrating electrodes formed on both main surfaces of a piezoelectric substrate in a spreading vibration mode.

Each terminal board 51, 71, 24, 34, 35,
37 and 39 are formed by Ag-plating a metal having relatively high elasticity such as phosphor bronze.
Contact protrusions are formed at the portions that come into contact with the central portions of 1a to 33a and 31b to 33b. This is formed by cutting press working and texturing from the above-mentioned metal member.

Further, the contact protrusions and the series piezoelectric elements 31a ...
33a, in order to enhance the contact stability with the parallel piezoelectric elements 31b to 33b, common terminal plates 34, 35, independent terminal plates 37,
Like the common piezoelectric element side of the common terminal plates 34 and 35 of FIG. 5, the structure of 39 is composed of a frame body and a cross-shaped molding portion, and one end of the cross-shaped molding portion is connected to the frame body so as to project to the lower surface. It is desirable that the contact protrusion is provided at the central portion of the cross-shaped diaphragm structure.

On the side of the serial piezoelectric elements of the common terminal plates 34, 35, two serial piezoelectric elements, for example, 31a,
It is necessary to form the above-mentioned contact protrusions on both main surfaces of the terminal plate 34 so that the 32a abuts at the same time. For this reason, a part of the common terminal plates 34, 35 (on the side of the laminated body 3a) is folded back to form an upward contact protrusion portion at the center of the flat plate.

That is, the common terminal boards 34, 35 are the same as the laminated body 3
Although it is commonly used to connect a and 3b, it has a substantially flat plate shape although a part thereof has a folded structure.

The material of the insulating spacers 36, 38 is an elastic member such as a silicon rubber plate, a plastic plate or the like, and its thickness is a predetermined thickness so that the common terminal plates 34, 35 can be arranged horizontally. Is set to That is,
The total thickness of the first series piezoelectric element 31a and the folded terminal portion of the common terminal plate 34, and the first parallel piezoelectric element 31b,
The thickness of the insulating spacer 36 is set to a predetermined value so that the total thickness of the insulating spacer 36 and the independent terminal plate 37 is the same.

Further, the cavity portion 11 of the lower case 1
The positions of the buried input terminal plate 51 and the buried ground terminal plate 71 buried in the inner bottom surface of the, that is, the depth from the upper end of the cavity portion 11 to the projection of the buried input terminal plate 51 and the buried ground terminal plate 71 is The first storage portion 111, which is the embedded earth terminal plate 71 side, is slightly deep so as to absorb the thickness difference between the first series piezoelectric element 31a and the first parallel piezoelectric element 31b. In addition to the method of absorbing the difference in thickness between the first series piezoelectric element 31a and the first parallel piezoelectric element 32b depending on the depth of the housing portion 111, the embedded input terminal plate 51 and the embedded ground terminal plate 71 are formed. The height of the protruding portion may be slightly increased on the embedded earth terminal plate 71 side.

Next, in the above structure, the sealing structure and the assembling structure will be described.

First, the lower case 1 as described above is prepared.

Next, the first series piezoelectric element 31a is planarly placed on the embedded input terminal plate 51 of the first housing portion 111 of the lower case 1, and the buried earth of the second housing portion 112 is placed. The first parallel piezoelectric element 31b is placed on the terminal plate 71 in a plane.

Next, the common terminal plate 34 is planarly arranged on the first series piezoelectric element 31a and the first parallel piezoelectric element 31b straddling the first storage section 111 and the second storage section 112. Overlay and arrange.

Next, the common terminal 34 of the second storage section 112.
The insulating spacer 36 and the independent terminal plate 37 are respectively placed on the top in a plane. At this time, the independent terminal plate connecting portion 37a protruding from the independent terminal plate 37 comes into contact with the ground terminal electrode connection 7a of the cutout portion 12b.

Next, the common terminal plate 3 of the first storage portion 111
4, the second series piezoelectric element 32a is placed in a plane, and on the independent terminal plate 37 of the second housing portion 112,
The second parallel piezoelectric element 32b is placed flat.

Next, the common terminal plate 35 is planarly arranged on the second series piezoelectric element 32a and the second parallel piezoelectric element 32b, straddling the first storage section 111 and the second storage section 112. Overlay and arrange.

Next, the common terminal 35 of the second storage portion 112.
The insulative spacer 38 and the independent terminal plate 39 are placed on a flat surface. At this time, the independent terminal plate connecting portion 39a protruding from the independent terminal plate 39 comes into contact with the ground terminal electrode connection 7b of the cutout portion 12c.

Next, the upper case 2 is placed and covered so as to cover the cavity 11.

As a result, the two protrusions of the embedded output terminal plate 24 embedded in the upper surface of the inner surface of the upper case 2 come into contact with the third series piezoelectric element 33a and the third parallel piezoelectric element 33b. At the same time, the upper case 2 is formed by the notch 12a.
The connection portion 24a of the embedded output terminal plate 24 and the connection portion 6a of the output-side terminal electrode 6 formed on the above contact each other.

At this time, the protrusions 26b, 26c of the upper case 2
Will be fitted into the notches 12b and 12c.
The notch 12a formed in the storage cavity 11 of the lower case 1 is exposed from the notch 23a, and the embedded output terminal board 24 formed in the upper case 2 at the notch 12a is exposed.
The connection portion 24a of the output terminal electrode 6 and the connection portion 6a of the output terminal electrode 6 contact each other.

Next, the independent terminals 37, 3 by the mounting described above.
9 and the contact portions between the connecting portions 37a and 39a protruding from 9 and the connecting portions 7a and 7b of the ground terminal 7 and the embedded output terminal plate 24.
The contact portion between the connection portion 24a and the connection portion 6a of the output terminal electrode 6 is joined by spot welding, laser welding, or the like.

Next, the notches 23a, 2 of the upper case 2
The sealing member 4 is filled in the concave portion formed by 3c and the wall surfaces 11a, 11c of the cavity portion 11 that appear by recessing from the cutout portions 23a, 23c. Specifically, this recess is filled with an insulative sealing resin such as epoxy resin and cured by heat treatment. From this, the notch 23
The connection portions of the predetermined terminal plates 24, 37, 39 located at a and 23c and the predetermined terminal electrodes 6, 7 are completely hidden, and the lower case 1 and the upper case 2 can be hermetically sealed. .

The ribs 14b and 14d are formed on the outer surfaces of the side walls 11b and 11d of the cavity 11 of the lower case 1.
Are formed. Therefore, the lower case 1 is replaced by the upper case 2
When coated with, the side wall 11b of the cavity portion 11,
A slight gap is formed between 11d and the side walls 22b and 22d of the upper case 2. Then, when the sealing resin of the sealing member 4 is filled, the sealing resin causes a capillary phenomenon,
Since the root also goes around in this gap, the cutouts 23a, 2
Not only 3c but also the insulating sealing resin is sufficiently present in this gap, and the hermetic sealing property is further improved.

In the ladder type filter described above, the lower case 1 is formed with the cavity portion 11 having an opening on the upper surface, and the piezoelectric elements 31a to 33a, 31b to constitute the laminated bodies 3a, 3b are formed from the upper surface opening. 33b, common terminal boards 34, 35, insulating spacers 36, 38, independent terminal board 3
7, 39 (laminate body constituting members) are arranged in a plane.

Therefore, the superposing and arranging steps of the laminated body constituent members are very simple and can be easily carried out by the automatic assembling apparatus.

Further, the input terminal electrode 5, the output terminal electrode 6, and the ground terminal electrode 7 are integrally formed at the end of the base 12 of the lower case 1. Therefore, in the above-mentioned stacking / arrangement of the laminated body constituent members, it is possible to carry out without considering the connection with the input terminal electrode 5, the output terminal electrode 6, the ground terminal electrode 7, etc. The arrangement process becomes very simple. It is easy to make the exposed heights of the terminal electrodes 5, 6, 7 exposed on the end portion of the base 12, especially on the back surface, the same as in the conventional case, and the exposed height by the spring back due to the bending process of the lead portion is reduced. The difference is eliminated, the connection state with the printed wiring board can be easily made the same, and reliable and stable surface mounting can be performed. Further, unlike the conventional case, since the terminal electrode is formed in the lower case 1 without using the through hole in the bottom surface portion of the lower case, the airtightness of the inside of the container is particularly maintained.

Further, on the side wall 11c of the cavity portion 11 of the lower case 1, the cutout portions 12b, 12 for mounting the connection portions 37, 39 formed on a part of the independent terminal plates 37, 39 are placed.
c is formed, and the connecting portions 37a and 39a of the independent terminals 37 and 39 and the earth terminal electrode connecting portions 7a and 7b integrated with the earth terminal electrode 7 are connected in the cutout portions 12b and 12c and It is performed outside, which extends slightly beyond the cutouts 12b and 12c.

Therefore, since the stacking / arranging step and the connecting step of the laminated body constituent members are performed in separate steps, both steps are facilitated. Further, the terminal plates 37, 39 and the connecting portions 37a, 7a, 39a and 7b of the terminal electrode 7 are exposed to the outside,
Since the joining is performed at this portion, the connected state can be stably and reliably performed. This is because it can be performed while visually checking the connection state, and an arbitrary joining method for achieving strong joining can be used.

In the upper case 2, the joint between the connecting portion 6a of the output terminal electrode 6 and the connecting portion 24a of the terminal plate 24 on the output side, the connecting portions 7a and 7b of the ground terminal electrode 7 and the independent terminal plate. Cutouts 23a, 23a, 23c, 23c are formed to expose the joints between 37 and 39 with the connecting portions 37a, 39a. Further, the cutouts 23a, 23a, 2a, 2c are formed.
3c and 23c are filled with the insulating sealing resin of the sealing member 4,
It is hardened.

Therefore, the above-mentioned joining step can be performed reliably and easily by any joining method even after the upper case 2 is arranged, and the notches 23a, 23 are formed.
Since the joint portion is completely covered with the insulating sealing resin filled in a, 23c, and 23c, the connection reliability is further improved.

The cavity portion 1 of the lower case 1
1 side walls 11b and 11d, upper side case 2 side wall 22b,
Since the ridges 14b and 14d that come into contact with the inner surface of 22d are formed, when the cavity portion 11 of the lower case 1 is covered with the upper case 2, a slight gap is formed between the contact surfaces. . Then, since the insulating sealing resin filled in the cutouts 23a, 23a, 23c, 23c wraps around this gap, the side wall 1 of the cavity portion 11
Notches 23a, 23a, 2 through which 1a, 11c are exposed
Insulating resin can be supplied not only to 3c and 23c but also to the outer peripheral portions of the side walls 11b and 11d of the cavity portion 11 of the lower case 1, and as a result, inside the storage portion 11 in which the stacked bodies 3a and 3b are arranged. Can be hermetically sealed.

The ridges 14b and 14d may be formed on the side walls 22a to 22d of the upper case 2.

A terminal plate 51 which is integrated with the input terminal electrode 5 in the lower case 2 and is in contact with the piezoelectric element 31a.
However, a terminal plate 24 that is connected to the output terminal electrode 6 and is in contact with the piezoelectric elements 33a and 33b is embedded in the upper case 2. For this reason, since the terminal plate, which should originally be a part of the stacked bodies 3a and 3b, is buried in a part of the upper case 1 and the lower case 2, the thickness of the stacked bodies 3a and 3b is substantially reduced. In addition, the number of members to be laminated in the laminated body is also reduced, the laminating / arranging process is very simple, and the height of the ladder type filter can be reduced. At the same time, impact resistance is improved because the metal member of the case is embedded.

In the above embodiment, two sets of laminated body 3 are used.
Although described in a and 3b, the number of laminated bodies may be one, for example. Also, the ladder type filter of 6 elements using 3 series resonators and 3 parallel resonators has been described, but the number of elements is not limited to 6 and the number of elements is arbitrary according to the filter characteristics. It can be changed.

Although the embedded terminal plates 51 and 24 are embedded in both cases 1 and 2, respectively, they may be embedded in either case side.

Furthermore, the ladder type filter of 6 elements using 3 series resonators and 3 parallel resonators has been described, but the number of elements is not limited to 6 and the elements may be changed according to the filter characteristics. The number can be changed arbitrarily.

[0087]

As described above, according to the present invention, the piezoelectric elements and the terminal plates constituting the laminated body can be sequentially arranged horizontally inside the lower case and the upper case, particularly in the cavity of the lower case. , Its assembly structure can be greatly simplified,
A ladder type filter that can be automatically assembled. In addition, the terminal plate of the laminated body and the terminal electrode can be connected very stably and reliably, and the surface mounting type ladder filter has improved connection reliability. Further, since the terminal electrode is formed integrally with the lower case, the airtight sealing in the housing portion is improved and the bonding to the printed wiring board is stabilized.

Further, it becomes a surface-mounting type ladder type filter capable of surely hermetically sealing the inside of the case accommodating the laminated body.

Further, since the terminal plate is embedded in a part of the case body, the structure of the laminated body can be simplified,
It is a surface-mounted ladder type filter with a thin thickness and excellent impact resistance.

Further, since the terminal electrode is formed integrally with the lower case, it is easy to hermetically seal the inside of the housing portion, and the bonding to the printed wiring board is stabilized.

[Brief description of the drawings]

FIG. 1 is an external perspective view of a ladder type filter of the present invention.

FIG. 2 is a cross-sectional view showing a cross section taken along line XX in FIG.

FIG. 3 is a cross-sectional view showing a cross section taken along line YY in FIG.

FIG. 4 is a cross-sectional view showing a cross section taken along the line ZZ in FIG.

FIG. 5 is an exploded perspective view of the ladder type filter of the present invention.

FIG. 6 is an equivalent circuit diagram of the ladder-type filter of the present invention.

FIG. 7 is a plan view of a lower case used in the ladder type filter of the present invention.

FIG. 8 is a perspective view of the upper case used in the ladder type filter of the present invention viewed from the lower surface side.

[Explanation of Codes] 10 ... Ladder type filter 1 ... Lower case 11 ... Cavity part 111 ... First storage part 112 ... ..Second storage portions 11a to 11d ... Side walls 12a, 12b, 12c ... Cutout portions 14b, 14d ...・ Sidewalls 23a, 23d ... Cutouts 24 ... Embedded output terminal board 24a ... Embedded output terminal board connecting portions 3a, 3b. 33a ... Series piezoelectric elements 31b to 33b ... Parallel piezoelectric elements 34, 35 ... Common terminal plates 36, 38 ... Insulating spacers 37, 39.・ Independent terminal board 4 ・ ・ ・ Seal member 5 ・ ・ ・ Input terminal electrode 51 ・ ・ ・ Embedded Power terminal plate 6 ... Output terminal electrode 6a ... Output terminal electrode connection portion 7 ... Ground terminal electrode 71 ... Embedded ground terminal plate 7a, 7b ... Ground terminal electrode connection portion

Claims (5)

[Claims] 1. A laminated body including a plurality of piezoelectric resonators and a plurality of terminal plates, wherein an input / output terminal electrode and a ground terminal electrode are integrally formed, and a cavity portion having an opening on an upper surface is formed. A ladder-type filter characterized in that each piezoelectric resonator and a terminal plate are arranged horizontally in a housing body composed of a housing-shaped lower case and an upper case that covers the cavity portion. 2. The ladder type filter according to claim 1, wherein a notch is formed in a side wall of the cavity of the lower case, and the terminal plate 1 is formed through the notch.
A ladder-type filter characterized in that a terminal plate connecting portion extending from one end is led out to the outside of the cavity portion and is connected to a terminal electrode connecting portion extending from the terminal electrode outside the cavity portion. 3. The ladder type filter according to claim 2, wherein the upper case has a side wall facing the outer surface of the side wall of the cavity in the upper case, and the side wall has the terminal electrode connecting portion and the terminal. A ladder-type filter, characterized in that a cutout portion that exposes a connection portion with a plate connection portion is formed, and the cutout portion is filled with an insulating sealing resin. 4. The ladder type filter according to claim 3, wherein a protrusion is formed on an outer surface of a side wall of the cavity portion of the lower case and / or an inner surface of a side wall of the upper case, and the side wall outer surface of the cavity portion is formed. Between the inner surface of the side wall of the upper case,
A ladder-type filter characterized in that a gap is formed by the protrusions and the gap is filled with an insulating sealing resin. 5. The ladder type filter according to claim 1, wherein a part of the upper case and / or the lower case of the housing is provided.
A ladder type filter, wherein a terminal plate that is in contact with the piezoelectric resonator that constitutes the laminated body and that is connected to one of the terminal electrodes is embedded.