JPH08330896A - Ladder type filter - Google Patents

Abstract

(57) [Summary] [Objective] The present invention is suitable for surface mounting on a printed wiring board.
Also, the present invention relates to a ladder type filter that can be applied to an automatic assembling apparatus. [Structure] Series piezoelectric resonators 31a to 33a and a terminal plate 34,
A series laminated body 3a composed of 35 and a parallel piezoelectric resonator 31.
b-33b, the terminal plates 34, 35, 37, 39, and the insulating spacers 36, 38, the parallel laminated body 3b, the input / output terminal electrodes 5, 6 and the ground terminal electrode 7 are integrally formed, and 2 The ladder-type filter 10 is arranged in a container including a housing-shaped lower case 1 having a cavity 11 made up of two housings 111 and 112, and an upper case 2 concealing the housing cavity 11. Then, from the opening on the upper surface side of the storage section 111, the laminated body 3 a is inserted into the storage section 112.
From the opening on the upper surface side of the laminated body 3b to the respective laminated bodies 3a,
The constituent members of 3b are superposed in a plane.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is a ladder type filter which is suitable for surface mounting on a printed wiring board and which can be automatically assembled. Two sets of laminated bodies each consisting of a piezoelectric element and a terminal plate are arranged in a horizontal direction. The present invention relates to a ladder type filter that is arranged.

[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.

The laminated body comprises 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 (parallel piezoelectric elements) forming a parallel circuit section of a ladder type circuit. The series piezoelectric element and the parallel piezoelectric element are composed of terminal plates of various structures for forming a ladder type circuit, and lead portions extend to the terminal plates for input / output and ground potential.

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 a predetermined terminal plate forming the two stacked bodies penetrates the bottom surface of the lower case and extends 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 the springback of the lead portion, and stable characteristics cannot be derived.

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

Further, in the lead portion penetrating from the bottom surface, the lead portion cannot be inserted unless the through hole is set to be slightly larger than the lead portion. If a gap is formed between the lead portion and the through hole, it becomes difficult to completely hermetically seal the inside of the laminated body,
As a result, corrosion may occur on the terminal plate and vibrating electrode,
It is not a ladder filter that can derive stable characteristics over a long period of time.

Further, since the common terminal board common to both laminated bodies is bent at the central portion thereof and a step is formed on the terminal board, even if an attempt is made to dispose this common terminal board, it will be However, it was difficult to place them in a stable manner.

Furthermore, since the two laminated bodies have the series piezoelectric elements and the parallel piezoelectric elements mixed, it is necessary to use the series piezoelectric elements or the parallel piezoelectric elements properly according to the laminating order of the respective laminated bodies. The stacking / arrangement becomes very difficult.

Further, since the electrical connection state between the terminals is complicated, it is necessary to use terminal plates of several different shapes when increasing or decreasing the number of stages of the ladder circuit, and the versatility is very low. .

The present invention has been devised in view of the above-mentioned problems, and an object thereof is to provide a surface on which two sets of a laminate consisting of a piezoelectric element and an end plate can be simply and reliably arranged in a case. An implementation type ladder type filter is provided.

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-mounting ladder type filter which can simplify the constitution itself of the piezoelectric element and the terminal plate constituting the laminated body.

[0019]

A first aspect of the present invention is to provide a lower case having two accommodating portions whose upper surfaces are open and at least input / output terminal electrodes and an earth electrode, and the two accommodating portions. An upper case for concealing the opening, a series circuit constituent member in which a plurality of piezoelectric resonance elements and a plurality of terminal plates are alternately laminated in a horizontal shape, a plurality of piezoelectric resonance elements, and for parallel connection between the piezoelectric resonance elements And a parallel circuit component formed by horizontally stacking the terminal plate of FIG. 1 and the serial circuit component in one storage part of the lower case, and the parallel circuit component in the other storage part. Type filter.

A second aspect of the present invention is the ladder type filter, wherein the terminal plate sandwiched between the two piezoelectric resonance elements of the series circuit constituent member is horizontally disposed between the two piezoelectric resonance elements of the parallel circuit constituent member. It is a common terminal board extending.

A third aspect of the present invention is the ladder-type filter described above, wherein between the two piezoelectric resonance elements of the parallel circuit constituent member, the common terminal plate, the insulating spacer, and the independent terminal plate connected to the ground terminal are provided. Intervened.

A fourth aspect of the present invention is the above-mentioned ladder type filter, wherein a bottom surface of one of the housings of the lower case is embedded with an embedded terminal plate connected to one of the input / output terminal electrodes and the other housing. An embedded terminal plate that is connected to the ground terminal electrode is embedded in the bottom surface, and an embedded terminal plate that is connected to one of the input / output terminal electrodes across the two accommodating parts is embedded in the ceiling surface of the upper case. It is buried.

[0023]

According to the first invention, the storage portion of the lower case is
Since the piezoelectric elements and the terminal plates constituting the laminated body can be horizontally overlapped and arranged from the top openings of the two housings, the laminating and arranging steps are very simple and can be easily performed by the automatic assembling apparatus.

At the same time, since the terminal electrodes connected to the terminal board are integrally formed on the lower case which is surface-mounted on the printed wiring board, the connection state between each terminal electrode and the printed wiring board is made the same. This facilitates reliable and stable surface mounting.

Moreover, since the terminal electrodes are integrally formed in the lower case, it is not necessary to form a through hole or the like in the bottom surface of the lower case, so that the laminated body is excellently hermetically sealed. .

In particular, the two accommodating portions have a laminated body composed of the piezoelectric resonance element and the terminal plate, which constitute the series circuit portion of the ladder type circuit, and a laminated body composed of the piezoelectric resonance element and the terminal plate, which constitute the parallel circuit portion. The body and the body are stored separately.
Therefore, in forming each laminated body, the arrangement and management of the piezoelectric resonance element forming the series circuit section and the piezoelectric resonance element forming the parallel circuit section are very simple.

According to the second invention, in addition to the above-mentioned operation,
In order to connect the two sets of laminated bodies, the terminal plate between the two piezoelectric resonance elements forming the series circuit part and the terminal plate between the two piezoelectric resonance elements forming the parallel circuit part are shared. Moreover, since this common terminal board has a substantially planar shape, the stacking and arranging steps are also very simple, and automatic assembly can be performed easily.

Generally, the piezoelectric resonance element forming the parallel circuit section has a smaller element thickness than the piezoelectric resonance element forming the series circuit section, so that the laminated body forming the parallel circuit section has a smaller thickness. According to the third invention, a common terminal plate is provided between the two piezoelectric resonance elements constituting the parallel circuit section,
An insulating spacer and an independent terminal plate connected to the ground terminal are interposed, and the thickness of the insulating spacer can be set to be substantially the same as the thickness of the laminated body forming the series circuit portion. Therefore, when the stacked bodies that form the series circuit and the stacked bodies that form the parallel circuit section are stacked in parallel at the same time, the common terminal board can be particularly arranged horizontally, so that the stacking / arranging process is more efficient. It will be easier.

Further, since the two piezoelectric elements forming the parallel circuit portion are electrically separated by the insulating spacer, the parallel circuit can be easily formed.

According to the fourth invention, a buried terminal plate connected to one of the input / output terminal electrodes is buried in the bottom surface of one of the housings of the lower case, and the ground terminal electrode is buried in the bottom of the other housing. An embedded terminal plate that is connected to the embedded case is embedded, and an embedded terminal plate that is connected to one of the input / output terminal electrodes is embedded on the ceiling surface of the upper case across the two storage portions. That is, the terminal board, which should originally be a part of both laminates,
Since it is embedded in a part of the case, the thickness of the laminated body is substantially reduced, the number of members to be laminated in the laminated body is also reduced, and the laminating / arranging process becomes very simple. At the same time, impact resistance is improved because the metal member of the case is embedded.

[0031]

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 of 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.
FIG. 5 is a sectional view taken along the line Z-Z, and FIG. 5 is an exploded perspective view.
In the embodiment, three piezoelectric resonance elements (hereinafter, serial piezoelectric elements) that configure the series circuit section of the ladder type circuit and three piezoelectric resonance elements (hereinafter, parallel piezoelectric elements) that configure the parallel circuit section of the ladder type circuit. The following description will be given using a six-element surface-mounted ladder-type filter composed of (elements).

In the figure, the ladder type filter 10 includes a lower case 1 and an upper case 2 which are accommodating bodies, a laminated body 3a of serial circuit constituent members in which three serial piezoelectric elements and a terminal plate are alternately laminated, and 3a. It is composed of a laminated body 3b of parallel circuit constituent members in which one parallel resonant piezoelectric element, a terminal plate and the like are alternately laminated, and a sealing member 4.

The lower case 1 is made of an insulating resin and has a base 12 having substantially the same shape as that of the upper case 2 in plan view and four side walls 11a to 11d provided upright on the base 12. It is composed of a tee portion 11 and has a housing shape as a whole. 11 of this cavity part 11
A partition portion 13 for partitioning the cavity portion 11 into two storage portions 111 and 112 is provided in the central portion of a and 11c.
a and 13b are formed respectively. In addition, the partition 13
Although a and 13b are divided into two, they may be continuous partition walls.

Further, the input terminal electrode 5, the output terminal electrode 6, and at least one ground terminal electrode 7 are integrally formed of resin on the end side of the base 12 of the lower case 1. In the figure, the input terminal electrode 5 and the output terminal electrode 6 are formed on one end side of the base 12, and the ground terminal electrode 7 and the dummy terminal electrode 8 are formed on the other end side opposite to the one end side. ing. 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.

Further, the side wall 11a of the cavity portion 11
A cutout 12a having a connecting portion 6a extending from the output terminal electrode 6 is formed on a part of 11d to 11d, and a cutout having a connecting portion 7a, 7b extending from the ground terminal electrode 7a is formed on the side wall 11c. Parts 12b, 12c
Are formed respectively.

The cutout portion 12a is a slight cutout amount from the upper end of the accommodating cavity portion 11, and the cutout portion 12b is an approximate amount of the thickness of the parallel piezoelectric element from the upper end of the accommodating cavity portion 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 that is electrically connected to the stacked body 3 a and that is integral with the input terminal electrode 5 is provided in the first storage portion 111.
Is embedded in the second housing portion 112, and an embedded terminal plate 71 that is electrically connected to the stacked body 3b and is integral with the ground terminal electrode 7 is embedded in the second storage portion 112.

The upper case 2 is made of an insulative resin, has a top plate 21, and at least four side walls 22a to 22d surrounding the storage cavity portion 11 and has a substantially housing-like shape. Notches 23a and 23c are formed in 22a and 22c, respectively. In addition, column portions 25a and 25c that contact the surface of the base substrate 2 are formed in the central portions of the cutout portions 23a and 23c, and the cavity portion 11 is provided on the upper side of the cutout portion 23c.
Protrusions 26b and 26c that fit into the cutouts 12b and 12c formed on the side wall 11c 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 extends, for example, in the vicinity of the cutout portion 23a and serves as the embedded output terminal plate connection portion 24a.

Two sets of laminated bodies 3a and 3b are housed in the housing body constituted by the case bodies 1 and 2. Specifically, they are housed in the two housing parts 111, 112 of the cavity part 11 partitioned by the partition parts 13a, 13b, respectively.

The first accommodating section 111 has the laminated body 3a which mainly constitutes the series circuit section of the ladder type circuit, and the second accommodating section 1
In FIG. 12, the laminated bodies 3b mainly constituting the parallel circuit portion of the ladder type circuit are superposed and arranged. Here, the term “superposition / arrangement” means that the piezoelectric elements and the terminal plates that form each of the laminated bodies 3 a and 3 b are laminated / arranged in a substantially horizontal state on the base 12 of the lower case 1. .

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.

Specifically, the first series piezoelectric element 31a, the common terminal board 34, and the second series piezoelectric element are sequentially arranged on the embedded input terminal plate 51 from the opening side of the upper surface of the first housing portion 111. 32a, common terminal plate 35, third series piezoelectric element 33a
The stacked body 3a is configured by superposing and arranging the above. The terminal plate on the upper surface side of the third series piezoelectric element 33a is the embedded output terminal plate 2 embedded in the upper case 2 described above.
4, and when the upper case 2 is covered with the lower case 1, the laminated body 3a forming an electric circuit is achieved.

That is, as shown in FIG. 6, the embedded input terminal plate 51, the first series piezoelectric element 31a, the common terminal plate 34, the second series piezoelectric element 32a, the common terminal plate 35, and the third series piezoelectric element. 33a and the embedded output terminal board 24 are connected in series to form a series circuit portion of a ladder type circuit.

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.

Specifically, the first parallel piezoelectric element 31b, the common terminal plate 34, the insulating spacer 36, and the independent spacers are sequentially provided on the embedded earth terminal plate 71 from the opening side of the upper surface of the second housing portion 112. A terminal plate 37, a second parallel piezoelectric element 32b, a common terminal plate 35, an insulating spacer 38, an independent terminal plate 39,
The stacked body 3b is configured by superposing and disposing the third parallel piezoelectric elements 33b, respectively. The terminal plate on the upper surface side of the third parallel piezoelectric element 33b is the embedded output terminal plate 24 embedded in the above-mentioned upper case 2, and when the upper case 2 is covered with the lower case 1, an electrical circuit is formed. The laminated body constituting the above will be achieved.

In this laminated body 3b, the independent terminal board 3
Connection portions 37 a and 39 extending to the outside of the cavity portion 11 are formed on a part of the portions 7 and 39. The connecting portions 37a and 39a are arranged in the cutouts 12b and 12c when the independent terminal plates 37 and 39 are arranged at predetermined positions. Specifically, the connection portion 37a of the independent terminal board 37
Extends into the cutout portion 12b, and the cutout portion 12b
Then, it is connected to the ground terminal electrode connecting portion 7a. Further, the connection portion 39a of the independent terminal plate 39 extends to the cutout portion 12c, and the cutout portion 12c is used for the ground terminal electrode connection portion 7.
Connect with b. The notches 12b and 12c are covered with the upper case 2 so that the cutouts 12b and 12c are the protrusions 26b and 26c of the upper case 2.
Will be fitted and sealed.

That is, as shown in FIG. 6, the first parallel piezoelectric element 31b is connected between the common terminal plate 34 which is also connected to the first series piezoelectric element 31a and the embedded earth terminal plate 71, and the second parallel piezoelectric element 31b is connected. A common terminal plate 35 also connected to the series piezoelectric element 32a and an independent terminal plate 3 connected to a part of the ground terminal electrode 7.
The second parallel piezoelectric element 32b is connected between the
Embedded output terminal plate 24 that is also connected to the serial piezoelectric element 33a
And an independent terminal plate 39 connected to a part of the ground terminal electrode 7.
The third parallel piezoelectric element 33b is connected between and to form a parallel circuit portion of the ladder type circuit.

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

Each terminal plate 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. The contact protrusions are formed from the spring metal member by cutting and pressing, and at the same time, they are formed by texturing.

Further, the contact protrusion and the series piezoelectric element 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 series piezoelectric element side of the common terminal plates 34, 35, two series 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, as shown in the drawing, a part of the common terminal plates 34, 35 is folded back to form an upward contact protrusion portion at the center of the flat plate.

That is, the common terminal plates 34 and 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.

Next, the correspondence between the equivalent circuit diagram and the above-mentioned laminated structure will be described with reference to FIG.

In order to form the first stage ladder circuit from the input terminal electrode 5 side shown in FIG. 6, the input terminal electrode 5 is connected to the first series piezoelectric element via the embedded input terminal plate 51 shown in FIG. The element 31a is brought into contact with the first parallel piezoelectric element 31b and the second series piezoelectric element 32a via the common terminal plate 34 at the same time. The first parallel piezoelectric element 31b is connected to the ground terminal electrode 7 via the embedded ground terminal plate 71.

Similarly, in order to form the second stage ladder circuit, the common terminal plate 35 having the same shape as the common terminal plate 34 is used as the second terminal plate.
Of the series piezoelectric element 32a, the second parallel piezoelectric element 32b, and the third series piezoelectric element 33a. Here, one vibration electrode of the second parallel piezoelectric element 32b is connected to the ground terminal electrode 7
An independent terminal plate 37 is provided to connect to the. Then, by connecting the connection portion 37a extending from one end of the independent terminal 37 and the connection portion 7a of the ground terminal electrode 7, the second
The ladder circuit of the stage is achieved. In particular, an insulating spacer 36 is inserted between the common terminal 34 and the independent terminal plate 37 to prevent a short circuit between them.

Similarly, in the ladder circuit of the third stage, the embedded output terminal plate 24 embedded in the case 2 makes contact with the third series piezoelectric element 33a and the third parallel piezoelectric element 33b, and the embedded output terminal plate 24 is provided. A part of the connection portion 24a of the output terminal electrode 6 is connected to the connection portion 6a of the output terminal electrode 6.

Similar to the second parallel piezoelectric element 32b, the third parallel piezoelectric element 33b is in contact with the independent terminal plate 39, and the connecting portion 39a extending from one end of the independent terminal plate 39 and the connecting portion of the ground terminal electrode 7. By connecting 7b, a third stage ladder circuit is achieved. Here, an insulating spacer 38 is inserted between the common terminal 35 and the independent terminal plate 39.

The thickness of the insulating spacers 36 and 38 is set to a predetermined thickness so that the common terminal plates 34 and 35 can be arranged horizontally. That is, the first series piezoelectric element 31a
And the total thickness of the folded terminal portions of the common terminal board 34,
The thickness of the insulating spacer 36 is set to a predetermined value so that the total thickness of the first parallel piezoelectric element 31b, the insulating spacer 36, and the independent terminal plate 37 is the same.

The position of the embedded input terminal plate 51 and the embedded ground terminal plate 71 embedded in the inner bottom surface of the cavity 11 of the lower case 1, that is, from the upper end of the cavity 11 to the embedded input terminal plate 51, the embedded The depth of the ground terminal plate 71 to the protruding portion is the buried earth terminal plate 71 side of the first housing so that the difference in thickness between the first series piezoelectric element 31a and the first parallel piezoelectric element 31b is absorbed. The part 111 is slightly deeper. In addition to absorbing the difference in thickness between the first series piezoelectric element 31a and the first parallel piezoelectric element 32b due to the depth of the storage portion 111, the embedded input terminal plate 51 and the embedded ground terminal plate 7 are also provided.
1. The height of the protrusion formed in 1 is set as the embedded earth terminal plate 71.
May be slightly higher on the side.

The insulating spacers 37 and 39 may be made of an elastic material such as a silicon rubber plate or a plastic plate.

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

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

Next, the first series piezoelectric element 31a is placed flat 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 section 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, 26 of the upper case 2
c will fit into the notches 12b and 12c. A notch 12a formed in the storage cavity 11 of the lower case 1 is exposed from the notch 23a, and a connecting portion 24a of the embedded output terminal board 24 formed in the upper case 2 at the notch 12a and an output The connection portion 6a of the terminal electrode 6 abuts 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. .

In order to improve the airtightness between the lower case 1 and the upper case 2, the side walls 11a to 11d forming the storage cavity portion 11 of the lower case 1 and the side wall 22 of the upper case 2 are formed.
A protrusion is formed on one of the surfaces a to 22b that are in contact with each other so that a slight gap is formed between the surfaces, and the sealing resin of the sealing member 4 is collected in this gap. May be. In FIG. 5, on the side walls 11b and 11c of the cavity portion 11 of the lower case 1, the ridge portions 25b and 2 that extend in the height direction are provided.
5d is formed.

In the ladder type filter described above, as the first invention of the present invention, the opening of the cavity portion 11 formed of the two housing portions 111 and 112 of the lower case 1 is located on the upper surface side, and From the opening, the stack 3a, 3
Piezoelectric elements 31a to 33a and 31b to 33b constituting b
Also, since the terminal plates 34, 35, 37, 39 can be horizontally overlapped and arranged, the stacking / arranging process becomes very simple, and the automatic assembling apparatus can easily cope with them.

This is because the terminal electrodes 5, 6, 7 connected to the terminal boards 24, 51, 37, 39 are integrally formed on the lower case 1 which is surface-mounted on the printed wiring board. 24, 51, 37, 39 and the terminal electrodes 5, 6,
7, the side walls 11a, 1 of the cavity portion 11 which avoid the portions where the structural members of the stacked bodies 3a, 3b overlap.
Since it is performed outside the cutouts 12a, 12b, 12c formed in 1c, connection with the terminal electrodes 5, 6 is performed in the lamination / arrangement step of the laminated bodies 3a, 3b, and the lamination / arrangement as a whole is performed. The process can be performed very efficiently.

Since each terminal electrode 5, 6, 7, 8 is formed integrally with the lower case, the exposed height of each terminal electrode 5, 6, 7, 8 exposed at the end of the base 12, especially on the back surface, is adjusted. The same problem can be solved, the problem of springback due to bending of the lead part as in the past can be solved, the connection state with the printed wiring board can be easily made to be in the same plane state, and reliable and stable surface mounting can be performed. it can.

Further, unlike the conventional case, it is not necessary to form a through hole or the like on the bottom surface of the lower case 1, so that the laminated bodies 3a, 3
b can be sealed with high airtightness in the storage portions 111 and 112.

In particular, since the laminated body 3a having the series circuit configuration of the ladder type circuit and the laminated body 3b having the parallel circuit configuration are respectively arranged in the storage portions which are distinguished in the cavity portion 11, the respective lamination layers are laminated. In constructing the bodies 3a and 3b, only the series piezoelectric elements 31a to 33a are stored in the first storage portion 111, and the parallel piezoelectric elements 31b to 33 are stored in the second storage portion 112.
Since only b is required to be laminated, the piezoelectric elements 31a to 33a
The stacking management of a and 31b to 33b becomes very simple.

According to the second invention, in addition to the above-mentioned action,
Since the common terminal plates 34, 35 for connecting the two sets of the laminated bodies 3a, 3b are formed in a substantially flat plate shape, the stacking / arranging process is also very simple, which is easy with an automatic assembling apparatus. And the series piezoelectric elements 31a ...
It is possible to stabilize the contact state with the 32a and the parallel piezoelectric elements 31b to 32b.

According to the third invention, in particular, the common terminal plate 3 is provided between the two parallel piezoelectric resonant elements of the laminated body 3b on the parallel side.
4, 35, insulative spacers 36, 38, and independent terminal plates 37, 39 connected to the ground terminal are interposed. Particularly, by controlling the thickness of the insulative spacers 36, 38, substantially the series resonance It can be substantially the same as the thickness of the laminated body 3a. This is because the common terminal plates 34 and 35 can be arranged horizontally when, particularly, when the laminated body 3a on the series resonance side and the laminated body 3b on the parallel resonance side are laminated and arranged in parallel at the same time. Also, the stacking / arranging process becomes easier.

Further, by interposing the insulating spacers 36 and 38, the parallel piezoelectric elements 31b to 33b can be electrically isolated from each other, and the parallel circuit portion of the ladder type circuit can be stably formed easily. . As a result, unlike the conventional case, a series piezoelectric element and a parallel piezoelectric element are not mixed in one laminated body, and it is not necessary to use a U-shaped coupling terminal plate. management,
The structure of the terminal is simplified.

According to the fourth invention, a buried input terminal plate 51 connected to the input terminal electrode 5, for example, is buried in the bottom surface of the first housing portion 111 of the lower case 1, and in the second housing portion. Embedded earth terminal plate 71 connected to the earth terminal electrode 7
Is buried.

Therefore, in practice, it is not necessary to arrange the lowermost terminal plate in the laminated body, the thickness of the laminated body is reduced, and the number of members to be laminated in the laminated body is reduced.・ The placement process is very simple. At the same time, impact resistance is improved because the metal member of the case is embedded.

Further, throughout the present invention, in the embodiment, three piezoelectric elements 31a to 33a and 31b to 33 are provided, respectively.
The ladder-type filter configured in b is a versatile ladder because even if the number of elements increases or decreases, the common terminal plate, the insulating spacer, and the independent terminal plate can be easily changed in terms of the circuit. Can be called a type filter.

[0088]

As described above, according to the present invention, in a container formed of an upper case and a lower case, a laminated body which constitutes a series circuit portion including a piezoelectric element and a terminal plate and a laminated body which constitutes a parallel circuit portion are laminated. The body is arranged separately in the storage part,
With this superposition / arrangement, the piezoelectric element, the terminal plate, etc. can all be arranged horizontally from the opening on the upper surface, so that the superposition / arrangement can be easily and reliably arranged, and the ladder type filter can be automatically assembled.

Further, since the terminal electrodes are 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, since the common terminal plate commonly used for the laminated body which constitutes the series circuit part and the laminated body which constitutes the parallel circuit part is plate-shaped, it can be arranged easily and surely. .

Further, since the common electrode, the insulating spacer, and the independent terminal plate are arranged between the piezoelectric elements of the laminated body forming the parallel circuit portion, the laminated body forming the parallel circuit can be simplified in structure. Even if the number of stages of the ladder circuit is increased or decreased, the constituent members of the laminated body are not changed, and the versatility is high. In addition, the thickness of the insulating spacer can absorb the difference in thickness between the laminated body forming the series circuit part and the laminated body forming the parallel circuit part, which also simplifies the superposition and arrangement.

Since the terminal plate is embedded in a part of the case body, the structure of the laminated body can be simplified.

[Brief description of 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 filter of the present invention.

[Explanation of symbols]

 10-Ladder type filter 1-Lower case 11-Storage cavity 111-First storage 112-Second Storage portions 11a to 11d ... Side walls 12a, 12b, 12c ... Notched portion 2 ... .... Buried output terminal plate 24a ... Buried output terminal plate connecting portion 3a, 3b ... Laminated body 31a-33a ... Series piezoelectric element 31b-33b ...・ Parallel piezoelectric elements 34, 35 ・ ・ ・ ・ ・ ・ Common terminal plates 36, 38 ・ ・ Insulating spacers 37, 39 ・ ・ Independent terminal plates 4 ・ ・ ・ ・ Sealing member 5 ... Input terminal electrode 51 ... Embedded input terminal plate 6 ... Output terminal electrode 6a ...・ Output terminal electrode connecting part 7 ・ ・ ・ Grounding terminal electrode 71 ・ ・ ・ Embedded grounding terminal plates 7a, 7b ・ ・ Grounding terminal electrode connecting part

Claims (4)

[Claims] 1. A lower case having two storage parts whose upper surfaces are opened and having at least input / output terminal electrodes and a ground electrode formed thereon, and an upper case which covers the openings of the two storage parts. A series circuit constituent member in which a piezoelectric resonance element and a plurality of terminal plates are alternately laminated in a horizontal shape, a plurality of piezoelectric resonance elements, and a terminal plate for parallel connection between the piezoelectric resonance elements are laminated in a horizontal shape. A ladder type filter comprising a parallel circuit constituent member, wherein the series circuit constituent member is accommodated in one accommodating portion of the lower case and the parallel circuit constituent member is accommodated in the other accommodating portion. 2. The terminal plate sandwiched between the two piezoelectric resonance elements of the series circuit constituent member is a common terminal board extending horizontally between the two piezoelectric resonance elements of the parallel circuit constituent member. Item 1. A ladder type filter according to item 1. 3. A common terminal plate, an insulating spacer, and an independent terminal plate connected to the ground terminal are interposed between the two piezoelectric resonance elements of the parallel circuit constituent member. Ladder filter described. 4. A buried terminal plate connected to one of the input / output terminal electrodes is buried in one bottom surface of the lower case, and a bottom terminal plate connected to the ground terminal electrode in the other bottom surface. 2. The embedded terminal plate is embedded in the ceiling surface of the upper case and is connected to one of the input / output terminal electrodes across the two storage portions. Ladder filter described.