JP3157975B2 - Ladder type filter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ladder type filter, and more particularly to a surface mount type ladder type filter.

[0002]

2. Description of the Related Art Conventionally, as a surface mount type ladder type filter, a part of a terminal plate of a laminated body including a piezoelectric resonator and a terminal plate housed in a case is used as a lead terminal to extend outside the case. Using a normal ladder-type filter, specifically, a lead terminal extending to the outside of the case was bent to make the end of the lead terminal approximately parallel to the bottom surface of the case (the joint surface of the wiring board) ( No. 2-32322).

In such a surface mount type ladder type filter, in order to bend a lead terminal extending outside the case using a bending jig or the like, the bent portion of the lead terminal and the case need to be bent. It was necessary to provide a sufficient interval between them. For this reason, when the surface mount type ladder type filter is surface-mounted on the printed wiring board, there is a problem that the occupied area required for the joining becomes very large. In addition, the control of the bending jig causes a deformation state of the bending process among a plurality of lead terminals, and there is a problem that it is difficult to obtain lead terminals that are uniformly bonded to a printed wiring board.

This is because the lead terminal, which is a part of the terminal plate extending from the case, is simply bent using a normal lead-bonded ladder-type filter so as to be compatible with a surface mount type. It is.

Therefore, the present inventor has proposed a ladder-type filter in which a terminal plate and a lead terminal are formed as separate members as a structure suitable for a surface-mount type ladder-type filter. Also,
A ladder-type filter has been proposed in which the terminal plate, the lead terminal, and the intermediate conductor for connecting the two are formed of different members.

A ladder-type filter in which the terminal plate and the lead terminal are formed as separate members is, for example, Japanese Utility Model Laid-Open No. 5-4622, in which all the lead terminals are integrally formed on a lid. A part of the plate is connected to a lead terminal near the lid. According to this, since the bending of the plurality of lead terminals can be performed during the processing of the lid, the processing can be performed easily and with high accuracy. As a result, the joint surfaces of the plurality of lead terminals can be reliably formed on the printed wiring board. It can be joined to.

A ladder-type filter in which the terminal plate, the lead terminal, and the intermediate conductor are formed as separate members is disclosed in, for example, Japanese Utility Model Application Laid-Open No. Hei 5-22691. The cover is integrally formed by molding so as to be exposed on the bottom side, and the lid is integrally formed with an intermediate conductor for connecting a part of the terminal plate and a lead terminal integrated with the case. In particular, one of the plurality of lead terminals is routed to the end on the side facing the opening by using the bottom surface of the case in order to ensure the bonding stability when the surface is mounted.

[0008]

SUMMARY OF THE INVENTION
In the surface mount type ladder type filter 622, since the bending of the lead terminal is obliquely led outward from the opening, when mounted on a printed wiring board, the effect of reducing the occupied area can be sufficiently obtained. I can't. In the case of reflow soldering, only one end side of the opening side is bonded, so that the bonding stability is lacking, and further, solder soldering (solder fillet) is not sufficiently formed, and sufficient bonding is performed. There was a problem that strength could not be obtained.

In the surface mount type ladder filter disclosed in Japanese Utility Model Application Laid-Open No. 5-22691, since the lead terminals are formed integrally with the case, a sufficient amount of solder fillet is particularly provided at the lead terminals on the case opening side. However, there was a problem that it could not be formed. This is because it is regulated by the thick part of the case around the opening.

The present invention has been devised in view of the above-mentioned problems, and has as its object to define the structure and arrangement of lead terminals so that a solder fillet can be reliably formed.
An object of the present invention is to provide a ladder-type filter that minimizes the occupied area required for surface mounting and that has excellent surface-mounting stability.

[0011]

According to the present invention, there is provided a laminated body in which a plurality of piezoelectric resonators are connected in a ladder circuit via a plurality of terminal plates, and a hollow portion for accommodating the laminated body. A case having an opening at one end, an exposed portion exposed to the inner wall of the opening of the case, and a joining portion at the bottom and side surfaces of the other end of the case, and a case formed integrally with the case. One lead terminal, one intermediate conductor that fits into the opening and connects the predetermined terminal plate and the first lead terminal, and two second lead terminals connected to the predetermined terminal plate are integrally formed. A ladder-type filter comprising: a lid formed in the above; and a sealing material that fills a space defined by an inner wall of the opening of the case and an outer surface of the lid, and covers the intermediate conductor. To form ribs on the outer surface to partition into three areas In the three regions, the intermediate conductor is disposed at the center of the three regions, and the second lead terminals are disposed on both sides of the intermediate conductor, and the second lead terminals are extended outwardly of the sealing material. An extending portion, a solder fret forming portion bent substantially vertically downward from the extending portion, and a wiring board joint portion bent from the solder fret forming portion to the case side were formed in a substantially U-shaped cross section. This is a ladder-type filter characterized by the following.

[0012]

According to the present invention, when the first lead terminal and the second lead terminal are distributed to the opposite ends of the case and led out, the first lead terminal and the second lead terminal can be mounted on a printed circuit board. The joining stability is improved.

[0013] Further, the second lead terminal has an extension protruding outward of the sealing material in the opening, and a solder fillet forming portion bent downward and substantially vertically from the extension.
When surface mounting is performed on a printed wiring board, a solder fillet of reflow-treated solder can be sufficiently formed, and thus strong bonding can be achieved.

Further, since the end of the second lead terminal, that is, the connection portion of the wiring board is bent toward the case and has a substantially U-shaped cross section as a whole, the mounting area on the printed wiring board is minimized. Can be

Note that, structurally, the piezoelectric resonator, the terminal plate, and the first lead terminal are integrated and a case body having an opening, the second lead terminal connected to the terminal plate, the terminal plate and the first
And a lid body integrally formed with an intermediate conductor for connecting the lead terminal to the lead terminal, so that the number of components does not increase, and there is no deterioration in productivity.

Two second materials are formed from the sealing material filled in the opening.
Only the lead terminals of the above are extended. That is, in the lid for fitting the opening of the case, an intermediate conductor is disposed between the two second lead terminals, and the intermediate conductor and the second lead terminal are formed by ribs formed on the outer surface of the lid. It is divided into three areas. Therefore, since there is an intermediate conductor between the two second lead terminals, the distance between the two second lead terminals protruding outside the case is widened to ensure that both are short-circuited by solder bridging during surface mounting. In addition, the ribs formed on the lid can prevent the conductive resins connecting the intermediate conductor and the terminal plate and the second lead terminal and the terminal plate from flowing into each other's area and causing a short circuit. Therefore, it is possible to provide a highly reliable ladder-type filter capable of simultaneously preventing a short circuit during manufacturing and a short circuit during mounting.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A ladder type filter according to 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, and FIG. 2 is a view showing a cross section taken along line XX in FIG. In the embodiment, a four-element type including two series resonators and two parallel resonators will be described.

The ladder type filter 1 includes a piezoelectric resonator 11,
12, 13, 14, a filter member group (laminate) including terminal plates 21, 22, 23, and 24, a case 3 in which first lead terminals 41 are integrated, and second lead terminals 42, 43,
It is mainly composed of the lid 5 in which the intermediate conductor 44 is integrated.

As shown in FIG. 3, the case 3 is made of a resin having a relatively high melting temperature, for example, a liquid crystal polymer, and has a substantially rectangular parallelepiped shape having a housing hollow portion therein. An opening 31 is provided at one end of the case 3, and a slight step 32 is formed in the opening 31 as shown in FIG. 3. The step 32 acts on the positioning of the lid 5.

In the bottom surface of the end of the case 3 on the side of the opening 31, recesses 33 and 34 are formed. This depression 3
Reference numerals 3 and 34 denote the ends of the second lead terminals 42 and 43, which prevent the height of the ladder filter from increasing due to the thickness of the second lead terminals 42 and 43. Are temporarily held by the lid 5 in which the lead terminals 42 and 43 are integrated.

On the bottom and side surfaces of the other end of the case 3, first lead terminals 41 which are surface-mounted on a predetermined wiring pattern of a printed wiring board are integrally formed.

The first lead terminal 41 is made of, for example, metal-plated iron or the like having good solder wettability, such as Ag, and is buried in a thick portion on the bottom surface of the case 3. As shown in FIG. 3, the case 3 is exposed to the inner wall of the opening at one end where the opening 31 is formed.
As shown in FIG. 7, the case 3 is exposed at the bottom surface of the other end of the case 3 facing the opening 31, and the other end is bent and disposed on a part of the side surface orthogonal to the bottom surface of the case 3.
The one end portion of the case 3 exposed to the opening 31 side is particularly referred to as an exposed portion 41a of the first lead terminal, and the exposed other end portion of the bottom surface and the side surface is particularly referred to as the first lead terminal 41. It is called a joint 41b.

The structure of the case 3 and the integration of the first lead terminals 41 can be formed by resin molding.

In the above-described case 3, a group of filter members is arranged in a stacked manner. Specifically, as shown in FIG. 2, from below, a U-shaped terminal plate 2 serving also as the first and fourth terminal plates
1, the first series resonator 11, the second terminal plate 22, the second
The parallel resonator 12, the third terminal plate 23, and the second parallel resonator 1
3, a part of the U-shaped terminal plate 21 serving as a fourth terminal plate,
The series resonator 14 and the fifth terminal 24 are each sequentially laminated. When actually housed in the case 3, the first series resonator 11 and the second
A terminal plate 22, a second parallel resonator 12, a third terminal plate 23;
A second parallel resonator 13 is disposed, a second series resonator 14 and a fifth terminal 24 are laminated on the U-shaped terminal plate 21, and a filter member group is disposed in a gap above the inside of the case 3. The spring terminals 25 for stably connecting the respective terminal plates 21 to 24 and the piezoelectric resonators 11 to 14 are further laminated.

Each of the terminal plates 21 to 24 is made of a metal having a spring property, such as phosphor bronze, and is formed into a single plate shape, a folded laminated plate shape, a U-shaped cross section, or the like.

Protrusions 21 are provided on the main surfaces of the terminal plates 21 to 24 at the portions electrically connected to the resonators 11 to 14, respectively.
a to 24a are formed by press molding or the like.

The second terminal plate 22, the third terminal plate 23, and the fifth terminal plate 24 are formed with lead portions 22b, 23b and 24b extending from the main surface to the opening 31 of the case 3 in the horizontal direction. I have. Note that the lead portions 22b, 23b, 24b
When viewed from the top of the ladder-type filter, the ladder-type filters are displaced so as not to overlap each other and extend to the opening 31 of the case 3.

The piezoelectric resonators 11 to 14 have electrodes (
(Not shown) is formed of a piezoelectric ceramic plate member, and has a substantially square shape. First and second series resonators 1
The thicknesses of the first and second parallel resonators 12 and 13 are set to be larger than those of the first and second parallel resonators 12 and 13.

The lid 5 is made of a resin such as a liquid crystal polymer, for example, as shown in FIG.
Ridge ribs 52, 53 that partition the outer main surface of the
Two second lead terminals 42 integrated with the main body 51,
43 and one intermediate conductor 44. Then, as shown, the two second lead terminals 42, 43
An intermediate conductor 44 is disposed therebetween.

In the main body 51, each of the regions whose outer main surface is divided into three regions by the ridge ribs 52 and 53 is provided with a second region.
Through holes 54a, 54b and 54c from which the lead portions 22b, 23b and 24b of the terminal plate 22, the third terminal plate 23 and the fifth terminal plate 24 respectively extend. Around the through holes 54a, 54b, 54c, at least one ends of the second lead terminals 42, 43 and the intermediate conductor 44 integrated with the main body 51 are exposed.

Second lead terminal 4 embedded in main body 51
2, 43 and the intermediate conductor 44 are made of, for example, iron plated with a material having a good solder wetting property such as silver.

One end of each of the second lead terminals 42 and 43 is exposed at least around the through holes 54a and 54c, and the second lead terminals 42 and 43 extend outward from a predetermined position on one surface of the outside of the opening of the main body 51. It is protruding. The second lead terminals 42 and 43 projecting outward from the opening of the main body 51 are extended portions 42a and 43a projecting outward from the opening.
43a, the solder fillet forming portions 42b and 43b bent downward substantially vertically from the solder fillet forming portion 42b;
Wiring board joints 42c, 43 bent from 43b to the case 3 side so as to be arranged in the depressions 33, 34 of the case 3
c, and has a substantially U-shaped cross section as a whole.

Here, the extension amount of the extension portions 42a, 43a of the second lead terminals 42, 43 is
Is set so as to extend at least outside the opening 31 of the case 3, and is perpendicular or inclined to the main body 51.

The solder fillet forming portions 42b and 43b of the second lead terminals 42 and 43 are set so as to be substantially vertical on the printed wiring board, and the length (distance in the height direction) of the surface is In order to sufficiently form a rise (solder fillet) of the solder when mounting, for example, 1.
5 mm or more.

Further, the wiring board joints 42c and 43c of the second lead terminals 42 and 43 are substantially in contact with the predetermined wiring pattern of the printed wiring board from the solder fillet forming parts 42b and 43b to the case 3 side. It is formed by bending. The length has such a length that a part of the front end can be arranged in the depressions 33 and 34 formed on the bottom surface of the opening 31 of the case 3.

The intermediate conductor 44 has one end exposed at least around the through hole 54b and the other end extending vertically and downward. The exposed portion at the other end is referred to as a lead terminal connection portion 44a.

The above-described piezoelectric resonators 11 to 14, terminal plate 21
-24, the case 3, and the assembly of the lid 5 will be briefly described.
First, in the case 3, the piezoelectric resonators 11 to 14, the terminal plate 2
The filter components 1 to 24 and the spring terminals 25 are stacked and arranged in a predetermined order.

Next, a through hole 54 is formed in the opening 31 of the case 3.
A base thin plate 61 made of paper or film having holes or cuts formed at positions corresponding to positions a, b, and c. As a result, the terminal plate 22
To 24 lead portions 22b to 24b are inserted. The positioning of the base thin plate 61 is performed by a step 32 provided on the inner wall of the opening 31 of the case 3.

Next, the lid 5 in which the second lead terminals 42 and 43 and the intermediate conductor 44 are integrated is fitted into the opening 31 of the case 3. At this time, the lead portion 22b of the terminal plate 22 through which the base thin plate 61 is inserted projects from the through hole 54a of the lid 5, and the lead portion 23b of the terminal plate 23 through which the base thin plate 61 is inserted projects through the through hole 54b. The lead portion 24b of the terminal plate 24 through which the base thin plate 61 is inserted through the hole 54c.
Protrudes. The positioning of the lid 5 is performed via a thin base plate 61 at a step 32 provided on the inner wall of the opening 31 of the case 3.

Thus, the second lead terminals 42, 43 projecting from the lid 5 and having a substantially U-shaped cross section project outward from the opening 31, and the tips of the second lead terminals 42, 43 extend into the recesses 33 on the bottom surface of the case 3. 34.

The lead terminal connecting portion 44a at the lower end of the intermediate conductor 44 embedded in the lid 5 and the exposed portion 41a at one end of the first lead terminal 41 exposed from the inner wall of the opening 31 of the case 3 are close to each other. State.

Next, one ends of the intermediate conductors 44 of the second lead terminals 42 and 43 exposed around the through holes 54a to 54c and the terminal plate 2 protruding from the through holes 54a to 54c.
The lead portions 2b to 24b are electrically connected to the tips of the lead portions 22b to 24b by connecting members 62 such as solder or conductive resin. Here, the ridge rib 5 of the main body 51 of the lid 5 is provided.
2 and 53 are formed, so that a joint between one end of each second lead terminal 42 and the lead portion 22b, a joint between one end of the second lead terminal 43 and the lead portion 24b, and an intermediate conductor 44 Since the one end and the joining portion of the lead portion 23b are divided into the respective regions, the connecting members 62 do not short-circuit to the adjacent connecting portions.

At the same time, the lead terminal connection portion 44a of the intermediate conductor 44 and the exposed portion 41a of the first lead terminal 41
Are electrically connected by the connection member 63.

At this time, the main body 51 of the lid 5 is
Since the inner walls 2 and 53 are formed, the inner wall of the case 3 and the end faces of the ribs 52 and 53 come into contact with a relatively large area. And can be temporarily held stably.

Thus, the second terminal plate 22 is electrically connected to the second lead terminal 42 via the lead portion 22b, and the third terminal plate 23 connects the lead portion 23b and the intermediate conductor 44. The fifth terminal plate 24 is electrically connected to the second lead terminal 43 via the lead portion 24b.

Next, a sealing material 64 made of, for example, a thermosetting resin such as an epoxy resin is filled in a space region sandwiched between the lid 5 and the opening 31 of the case 3 and thermosetting is performed.

When the sealing material 64 such as a resin is filled and cured, the lid 5 has already been connected to the conductive connecting members 62 and 63.
And so on. Therefore, the connection portions between the lead terminals 42 and 43 of the lid 5 and the lead portions 22b and 24b and the connection portion between the intermediate conductor 44 and the lead portion 23b can be reliably covered. Accordingly, the inside of the case 3 does not communicate with the outside air, and the case 3 can be hermetically sealed with high reliability.

As a result, a filter in which the first series resonator 11, the parallel resonator 12, the second parallel resonator 13, and the second series resonator 14 are connected in a ladder form, and a stable operation can be achieved. Will be.

In the ladder-type filter described above, surface mounting is performed on a predetermined wiring pattern of a printed wiring board (not shown) by reflow soldering.

For surface mounting by reflow soldering, creamy solder is generally applied on a predetermined wiring pattern of a printed wiring board (not shown), and the wiring pattern coated with the creamy solder and the surface mount type ladder filter 1 are used. After being arranged so that each of the lead terminals 41, 42, and 43 comes into contact with each other, 20
The cream solder is melted by being put into a reflow furnace at about 0 ° C. and cooled, and the solder is cooled and hardened.

The solder melted by the reflow process spreads due to the solder wettability of the lead terminals 41 to 43. At this time, since the tip of the first lead terminal 41 is bent and disposed over the bottom surface and the side surface of the case 3, a part of the molten solder bent at a substantially right angle to the printed wiring board is processed. Rise up. Also, the second lead terminal 4
Solder fillet forming portion 42 which is an intermediate portion between 2 and 43
The solder rises to a part of b and 43b. As a result, strong mechanical bonding and reliable electrical connection between the lead terminals 41 to 43 and the predetermined wiring pattern of the printed wiring board are achieved.

At this time, in particular, the second lead terminals 42 and 43
It is desired that the area occupied by the surface mounting on the printed wiring board be minimized in the above structure, but in the present invention, in the second lead terminals 42 and 43, the outside of the opening 31 of the case 3 is required. Extensions 42a, 43a projecting toward
Of the solder fillet forming part 4
The portions 2b and 43b do not protrude greatly outside the case 3, and furthermore, the wiring board joint 42
Since c and 43c are bent toward the case 3 side,
Since the largest portions projecting outward from the case 3 are the solder fillet forming portions 42b and 43b, the occupied area can be minimized as a whole.

Here, it is desirable that the distance between the opening 31 of the case 3 and the solder fillet forming portions 42b, 4ba is zero (the periphery of the opening 31 of the case 3 and the second lead terminals 42, 43 are in contact with each other). . In this case, the sealing member 6
When the resin 4 is filled, the resin may spread to the second lead terminals 42 and 43 due to the surface tension of the resin, so it is important to control the viscosity of the resin to a predetermined value. .

Even if the resin spreads over the lead terminals 42 and 43, the main surface on which the solder for soldering on the printed wiring board is attached is different from the main surface on which the resin spreads. There is no possibility that the solder joints with 42 and 43 cannot be made, and the reliability of the electrical connection and the mechanical joint does not decrease. Conversely, when the resin of the sealing material 64 spreads to the tip portions of the second lead terminals 42 and 43, the resin reaches the gaps between the depressions 33 and 34 formed on the bottom surface of the case 3 and the lead terminals 42 and 43. , Lead terminal 42,
In some cases, the mechanical fixing between the case 43 and the case 3 may be strengthened.

Further, as described above, the wiring board joint 42
c, 43c are bent toward the case 3 side, and the solder fillets in the solder fillet forming portions 42b, 43b are changed to solder fillet forming portions 42b,
Since the solder fillet is formed on the main surface of the ladder 43b, the formation state of the solder fillet, that is, the bonding state between the printed wiring board and the surface mount type ladder type filter 1, can be easily visually checked. Can be determined by

Furthermore, although the lead portions 22b, 23b, 24b of the second terminal plate 22, third terminal plate 23, and fifth terminal plate 24 of the filter component extend toward the opening 31, The lead portion 23 b is connected to the first lead terminal 41 via the intermediate conductor 44 integrated with the main body 51 of the lid 5.
Is extended to the end of the case 3 on the side facing the opening 31. That is, two second lead terminals 42 and 43 are disposed at one end of the case 3 on the opening 31 side, and the first lead terminal 41 is provided at the other end of the case 3 facing the opening 31 side. Are located. That is, case 3
The second lead terminal and the first lead terminal are arranged separately at one end and the other end of the ladder filter. Therefore, when soldering is performed on a printed wiring board, the bonding stability of the surface mount type ladder filter is improved. Will be improved.

Further, of the entire lead terminals (three lead terminals in the embodiment), for example, the sealing material 64 of the opening 31 is used.
Lead terminals extending from the second lead terminals 42 and 43. Therefore, the interval between the two adjacent second lead terminals 42 and 43 can be easily widened as compared with the case where three lead terminals are usually routed from the opening. Thus, when soldering is performed on the printed wiring board, a short circuit phenomenon caused by the generation of a solder bridge between the lead terminals can be eliminated.

Further, it is possible to easily cope with the case where the number of lead terminals is increased, and conversely, it is also possible to easily cope with a small ladder type filter.

In the above-described embodiment, a four-element ladder-type filter using two series resonators and two parallel resonators has been described. However, the number of elements is not limited to four. The number of elements can be arbitrarily changed according to the filter characteristics.

[0061]

As described above, according to the ladder-type filter of the present invention, the lead terminals are respectively distributed to the opposite ends of the case and are bent so that a solder fillet can be formed. The solder fillet improves the bonding strength of the solder. In addition, the bonding stability of surface mounting is very excellent.

Since the second lead terminal disposed on the opening side of the case is bent into a substantially U-shaped cross section, the occupation area required for surface mounting can be minimized.

The lead terminals extending from the sealing material through the case opening are two second lead terminals,
As compared with the case where three lead terminals are extended, the interval between adjacent lead terminals can be widened, and the short-circuit phenomenon of the lead terminals can be eliminated.

[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 longitudinal sectional view showing a section taken along line XX in FIG.

FIG. 3 is an external perspective view of a case.

FIG. 4 is an external perspective view of a lid.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Ladder type filter 11-14 ... Piezoelectric resonator 21-24 ... Terminal plate 3 ... Case 31 ... Opening 41 ... 1st lead terminal 42, 43. 2nd lead terminal 41b ... joining part 42b, 43b ... solder fillet forming part 44 ... intermediate conductor 5 ... lid 64 ... sealing material

──────────────────────────────────────────────────続 き Continued on the front page (56) References JP-A-2-150052 (JP, A) JP-A-5-4624 (JP, U) JP-A-5-4623 (JP, U) JP-A-5-624 119130 (JP, U) Japanese Utility Model 375631 (JP, U) Japanese Utility Model 2-38820 (JP, U) Japanese Utility Model Utility Model 61-184320 (JP, U) Japanese Utility Model Utility Model 5-59953 (JP, U) Jikgyo 3-23703 (JP, Y2) (58) Fields investigated (Int. Cl. ⁷ , DB name) H03H 9/00-9/215 H03H 9/54-9/60

Claims (1)

(57) [Claims] 1. A case having a laminate in which a plurality of piezoelectric resonators are connected in a ladder circuit via a plurality of terminal plates, a hollow portion accommodating the laminate, and an opening at one end. A first lead terminal integrally formed in the case, and having an exposed portion exposed on the inner wall of the opening of the case and a bottom surface and a side surface of the other end of the case; and Fit together with the predetermined terminal plate and the
A lid body integrally formed with one intermediate conductor for connecting to one lead terminal and two second lead terminals for connecting to the predetermined terminal plate; an inner wall of the opening of the case and an outer surface of the lid body A ladder-type filter that is filled with a space to be filled and that seals the intermediate conductor , wherein a rib that partitions the lid into three regions is formed on an outer surface of the lid.
In each of the three regions, the middle conductor is provided at the center thereof.
And second lead terminals are arranged on both sides thereof, respectively, and
One, the second lead terminals, and the extending portion projecting outwardly of the sealing material, and solder fret forming portion that is bent downward substantially perpendicular from the extending portion, the case side from solder fret forming section ladder-type filter characterized by being formed in a substantially U-shaped cross section so as to have a bent the wiring board joints.