JPH05243808A - Surface mounting type dielectric filter - Google Patents

Abstract

PURPOSE:To simply set a lead part of a lead terminal formed on a capacitance substrate and a ground terminal on the same plane by providing a cut piece for abutting on the upper side end face of the capacitance substrate on the upper case, and pressing the cut piece. CONSTITUTION:In a part of the upper case 4 corresponding to the upper part of a capacitance substrate 2, cut pieces 42a, 42b are formed in a state recessed from the upper face. The cut pieces 42a, 42b abut on the upper side end face Y of the substrate 2, and press the substrate 2 downward. As a result, in an assembly process, lead parts 24a, 25b of input/output lead terminals 24, 25 extended out of the substrate 2, and a group terminal 32 can be corrected simply to the same plane, and after the assembly process, a correction process of the terminal becomes unnecessary, and high reliability is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dielectric filter suitable for surface mounting.

[0002]

2. Description of the Related Art Conventionally, a surface mount type dielectric filter has been composed of a filter portion including a plurality of resonators, a capacitor substrate, and a metal case. For example, FIG. 5 shows its typical structure.

The filter unit 1 includes a plurality of resonators 1a to 1e.
Are joined together, and are arranged on the flat lower case 3. As shown in FIG. 7, in each of the resonators 1a to 1e, a through hole 12 is formed in a block body 11 of a dielectric ceramic, and an inner conductor 13 is formed on an inner wall of the through hole 12.
Further, an outer conductor 14 is formed on the outer periphery of the block body 11 except the surface (open end surface) where one opening of the through hole 12 is exposed. In such resonators 1a to 1e, a slit 16 is formed on a joint surface with an adjacent resonator, and the interstage coupling K is made through the slit 16.

In the vicinity of the open end face of the filter part 1, the capacitive substrate 2 has its main surface substantially orthogonal to the lower case 3, that is, its main face is substantially the open end face of the filter part 1. They are arranged in parallel. The capacitor substrate 2 is made of, for example, an alumina substrate 21 having a predetermined dielectric constant, and capacitor electrodes 22a to 22f are formed on both main surfaces and / or one main surface thereof. The predetermined capacitance electrodes 22a to 22d and the inner conductor 13 of the predetermined resonators 1a, 1b, 1d, and 1e of the filter unit 1 are partially inserted into the through holes 12, and the pin portions 15a extend from the inserted portions. It is electrically connected by the pin 15. Further, the predetermined capacitance electrodes 22e and 22f of the capacitance substrate 2 have L-shaped input / output lead terminals 24,
25 is connected to the L-shaped input / output lead terminals 24, 2
The lead portions 24b and 25b of No. 5 extend to the outside so as to be substantially flush with the flat lower case 3. In addition to the input / output capacitance components C _in and C _out ,
Capacitive components C ₁ and C ₂ for capacitively connecting the predetermined resonators 1a and 1d, 1b and 1e to achieve a polarized filter, for example, are formed as needed.

The metal case is composed of a flat plate-shaped lower case 3 and a box-shaped upper case 4 whose one surface is open. From a predetermined position of the lower case 3, the ground terminals 32 ... ..

The surface mount type dielectric filter 1 having the above structure.
0 facilitates the resonators 1a to 1e and the capacitance substrate 2 first. Next, the L-shaped lead terminals 24 and 25 are brazed to the predetermined capacitance electrodes 22e and 22f of the capacitance substrate 2. After that, with the plurality of resonators 1a to 1e serving as the filter unit 1 temporarily held, the filter unit 1 and the capacitor substrate 2 are connected by soldering or the like with the connection pin 15. Further, cream solder or the like is applied to the surfaces of the lower case 3 and the upper case 4 that contact the outer conductors 14 of the resonators 1a to 1e, and the filter unit 1 and the capacitance substrate 2 are arranged on the lower case 3. Next, the upper case 4 is covered from above the filter unit 1, and finally soldered by reflowing or the like, and the filter unit 1 and the capacitance substrate 2 are shielded by the lower case 3 and the upper case 4.

When mounting the surface mount type dielectric filter 10 thus achieved on a printed wiring board (not shown), first, the leads of the lead terminals 24 and 25 formed on the printed wiring board are formed. Parts 24b and 25b, the electrode pads that come into contact with the ground terminals 32, ... Are coated with cream solder, and the pads and the lead terminals 24b and 25b3.
The dielectric filter 10 is arranged so that the two contacts with each other, and heat treatment is performed in a reflow furnace at the same time as other electronic components to achieve surface mounting.

[0008]

2. Description of the Related Art In order to reliably achieve surface mounting of such a dielectric filter 10, a ground terminal 32 ...
., And the lead portions 24b of the input / output lead terminals 24, 25,
25b and must be on the same plane.
This is because if the difference in level is slightly different, for example, 0.2 mm or more, even if solder bonding is performed with cream solder, a gap is created between any of the terminals and the pad, and electrical connection cannot be achieved.

Therefore, in assembling the above-described surface mount type dielectric filter 10, the lead portions 24b and 25b of the input / output lead terminals 24 and 25 formed on the capacitance substrate 2 and the ground terminal 32 extending from the lower case 3 ... Careful attention is required so that and are on the same plane.

However, in practice, in consideration of the outer size tolerance of the capacitance substrate 2, the tolerance when mounting the lead terminals 24 and 25, the tolerance of the connection between the filter portion 1 and the capacitance substrate 2, and the like, the lead terminal 24 is considered. The positions of the lead portions 24b, 25b of the input / output lead terminals 24, 25 may fluctuate by about 0.5 mm at the maximum, and the input / output lead terminals 24, 25 should be connected to the ground terminal 32 in consideration of such tolerance. It was extremely difficult to manufacture them in the same plane.

The present invention has been devised in view of the above problems, and an object thereof is to make the lead portion of the lead terminal formed on the capacitor substrate and the ground terminal easily on the same plane. It is to provide a surface mount type dielectric filter capable of performing the above.

[0012]

In order to achieve the above-mentioned object of the present invention, the present invention provides a filter section having a plurality of dielectric resonators, and an input / output capacitance of the dielectric resonators. A capacitor substrate having a component and arranged on the open end face side of the filter portion, and an upper case and a lower case for accommodating the filter portion and the capacitor substrate, and a ground terminal extends from the lower case to the outside. At the same time, a surface mount type dielectric filter in which the input / output lead terminals extend to the outside from the capacitance substrate, wherein the upper case is provided with a segment body that comes into contact with the upper end surface of the capacitance substrate, and by pressing the segment body. It is a surface mount type dielectric filter characterized in that a tip portion of an input / output lead terminal extending from a capacitance substrate is made to be the same plane as an extending plane of the ground terminal.

[0013]

As described above, according to the present invention, when the filter part and the capacitance substrate arranged in the lower case are covered with the upper case, the assembly process is performed by the section body provided in a part of the upper case. At the same time, the upper end surface of the capacitance substrate is pressed downward, the input / output lead terminals are set on the same plane as the ground terminal, and the connection pin and the segment body are bent so that the capacitance substrate is fixed at that position. Therefore, the assembled filter can surely position the input / output lead terminal on the same plane as the extension plane of the ground terminal, and the joining reliability of surface mounting is improved. Further, since the lead terminal and the ground terminal can be corrected during the assembling process, it is not necessary to correct the terminal after the assembling process, which simplifies the manufacturing process.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The surface mount type dielectric 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 surface mount type dielectric filter of the present invention, and FIG.
FIG. 3 is a sectional view taken along line A, and FIG. 3 is an equivalent circuit diagram thereof. still,
The same parts as those of the prior art will be described with the same reference numerals.

In the figure, a dielectric filter 10 is composed of a filter portion 1, a capacitor substrate 2, a lower case 3 and an upper case 4.

The filter unit 1 includes five dielectric resonators 1a ...
1e is joined and comprised. For example, dielectric resonator 1
As shown in FIG. 2, a is a through hole 12 penetrating a dielectric book 11 made of a dielectric ceramic such as barium titanate.
Is formed on the inner wall of the through hole 12, and the inner conductor 1 such as silver is formed.
3 is formed. Further, except for the end surface (open end surface) having one opening of the through hole 12, the dielectric block 11
An outer conductor 14 such as silver is formed on the outer peripheral surface of the. The inner conductor 12 and the outer conductor 13 described above are electrically connected via the other end face (short-circuited end face).

Further, the inner conductor 12 formed in the through hole 12
From the above, the connection pin 15 is embedded in the through hole 12 for connecting to the capacitance substrate 2. The connecting pin 15 has a pin portion 15a extending from the open end face side of the resonator 1a. The connection pin 15 is formed such that a phosphor bronze cylindrical portion having a thickness of, for example, about 0.1 mm and a pin portion 15a are formed at the tip thereof.

A plurality of dielectric resonators 1a to 1 having the above structure.
e is disposed on the flat lower case 3 as shown in FIG. The interstage coupling K in the circuit diagram of FIG. 3 is achieved by the slits 16 formed on the joint surface of the adjacent dielectric resonators.

The capacitance substrate 2 has at least input / output capacitances C _in and C _out , and as shown in FIG. 4, a substrate material having a predetermined dielectric constant, for example, an alumina substrate 21.
And capacitance electrodes 22a to 22f. In the figure, in addition to the input / output capacitances C _in and C _out , there are capacitance components C ₁ and C ₂ for polarization, and four capacitance electrodes 22a to 22d are formed on one main surface side of the substrate 21. Two capacitive electrodes 22e and 22f are formed on the other main surface. Further, on the substrate 21, the pin portion of the above-mentioned connection pin 15 is 15
Lead holes 23a to 23d into which a is inserted are formed. In addition, the lead hole 23a corresponds to the capacitor electrode 22a and the lead hole 2
3b is the capacitance electrode 22b, and lead hole 23c is the capacitance electrode 22.
c and the lead hole 23d are formed in the capacitance electrodes 22a to 22d so as to be electrically connected to the capacitance electrode 22d. The capacitance electrodes 22a to 22f are formed by applying silver or the like onto the alumina substrate after firing by screen printing and baking. The input / output capacitance C in FIG.
_in is generated between the capacitive electrodes 22a and 22e in the substrate thickness direction, and is electrically connected to the resonator 1a by the pin portion 15a of the connection pin 15, and the capacitance C ₁ is the extension portion of the capacitive electrode 22a and the capacitive electrode. 22c generated between the substrate surface and the resonator 1
d is electrically connected to the capacitance electrode 22c by the pin portion 15a, and the output capacitance C _out is equal to the capacitance electrodes 22d and 22f.
Between the resonator 1e and the resonator 1e are electrically connected by the pin portion 15a of the connection pin 15, and the capacitance C
₂ is generated between the extended portion of the capacitance electrode 22d and the substrate surface of the capacitance electrode 22b, and the resonator 1b is electrically connected to the capacitance electrode 22b by the pin portion 15a.

Further, L-shaped input / output lead terminals 24, 25 extend from the lower end surface X of the capacitance substrate 1 on the capacitance substrate 2. Specifically, the joint portion 2 of the input lead terminal 24
4a is connected to the capacitor electrode 22e by silver brazing,
The lead portion 24b is the ground terminal 32 of the lower case 3 described later.
The extension plane is substantially the same as the extension plane. The joint portion 25a of the output lead terminal 25 is connected to the capacitor electrode 22f by silver brazing or the like, and the lead portion 25b is extended so as to be substantially the same as the extension plane of the ground terminal 32 of the lower case 3 described later. There is.

The lower case 3 is made of a flat metal plate such as iron and has a plurality of ground terminals 32, ... Formed so as to extend in the same plane as the flat plate. Further, a protruding piece 31 joined to the upper case 4 is formed upward on the open end surface side of the filter portion of the lower case 3. The lower case 3 is formed with a cutout portion so as not to contact the input / output lead terminals 24 and 25 described above.

The upper case 4 is made of iron or the like having a thickness of 0.2 mm, for example, and is formed in a substantially box shape so as to cover the filter portion 1 and the capacitance substrate 2. In the figure, the filter portion 1 is formed so that the short-circuit end face side is exposed. Further, the upper case 4 is formed with windows 41 ... That expose a part of the open end faces of the resonators 1a to 1e. The window portions 41 ... Can remove a part of the outer conductor 14 in order to adjust the resonance characteristic of each resonator.

What is important in the present invention is that the part of the upper case 4 corresponding to the upper part of the capacitive substrate 1 is formed with the cutouts 42a and 42b which are recessed from the upper surface. Specifically, a part of the side surface on the open end surface side of the upper case 4 is formed by bending. This section 42a, 42b
Touches the upper end surface Y of the capacitance substrate 2, and thus pushes the capacitance substrate 2 downward.

Next, the method of assembling the surface mount type dielectric filter of the present invention will be simply connected. First, the capacitance substrate 2 is prepared by connecting the resonators 1a to 1e in which the connection pin 15 is embedded in the inner conductor 13 and the input / output lead terminals 24 and 25.

Next, the resonators 1a to 1e are placed on the alignment jig.
Is temporarily held in a state of being bonded through the bonding surface, and the resonator 1
The capacitance substrate 2 is connected to a to 1e with the connection pin 15. Specifically, the pin portion 15a of the connection pin 15 is penetrated through the lead holes 23a to 23d, and the pin portion 15a protruding from the capacitance substrate 2 and the capacitance electrodes 22a to 22d are soldered.

Next, cream solder is applied to the contact portion of the mounting portion of the filter portion 1 of the lower case 3.

Next, the lower case 3 is placed on the lower heater block (not shown), the bonded body of the filter portion 1 and the capacitive substrate 2 is placed, and the lower case 3 and the filter are heated by heating the heater block. Solder joining is performed with the portion 1. This state is shown in FIGS.

Here, it is important to note that, as shown in FIG. 6, the lead portions 24b of the lead terminals 24, 25 in the state where the lower case 3 and the filter portion 1 are soldered together.
It is important that the bottom surface of 25b is raised above the bottom surface of the ground terminal 32 of the lower case 3 at the same or extremely narrow interval d. That is, when the dimensions of the capacitance substrate 2 and the tolerances due to the mounting of the lead terminals 24, 25 are all maximized, the bottom surfaces of the lead portions 24b, 25b and the ground terminal 32 are
It is sufficient to set so that the bottom surfaces of are the same.

Next, cream solder is applied to the upper case 4 which comes into contact with the outer conductor 14 of each of the resonators 1a to 1e, and on the table,
The upper case 4 is arranged so as to cover the filter portion 1 and the capacitor substrate 2, and the heated upper heater block is pressed against the upper case.

In the initial state, the section body 42 of the upper case 4
The a and 42b come into contact with the capacitance substrate 2, and the capacitance substrate 2 is further pushed down by the segment bodies 42a and 42b. Then, the pin portion 15a of the connection pin 15 connecting the capacitance substrate 2 and the filter portion 1 is bent, and the lead terminals 24 and 25 extending from the capacitance substrate 2 come into contact with the reference base. At the time of this contact, the pressing force of the heater block is applied to the segment bodies 42a and 4a.
By acting on 2b, the segment bodies 42a and 42b are bent slightly upward while being in contact with the upper end surface of the capacitance substrate 2. Then, when the upper case 4 and the outer conductor 14 of the resonators 1a to 1e come into contact with each other, the bending operation of the segment bodies 42a and 42b ends.

Then, by returning the temperature to room temperature, the upper case 4 and the filter portion 1 are firmly soldered to each other, and the surface mount type dielectric filter is completed.

Here, the important thing is that the section bodies 42a, 4a
The material of 2b, that is, the material of the upper case 4 is elastic (springy).
There is no choice. That is, the lead terminal 2
Connect the lead parts 24b and 25b of 4, 25 to the ground terminal 32.
..After being corrected to the same plane as that of the lead terminals 24 and 25 of the lead terminals 24 and 25 by springback or the like
This is to prevent b from protruding beyond the ground terminals 32.

The positions of the segment bodies 42a and 42b bent from the side wall of the upper case 4 on the open end face side. That is,
This is a position that is sufficient to push down the raised distance d in FIG. 6 and does not cause damage to the capacitance substrate 2. Specifically, the maximum bending amount of the segmented bodies 42a and 42b varies depending on the mounting of the lead terminals 24 and 25, the dimensional variation of the capacitance substrate 2, and the maximum tolerance of the variation when the filter unit 1 and the capacitance substrate 2 are connected. Set it to the same as. For example, in consideration of the bending allowance of about 0.4 mm, the segment bodies 42a and 42b are bent at a predetermined position on the side wall on the open end face side of the upper case 4.

Although the lower heater block and the upper heater block are used in the above-mentioned assembly process, the lower case 3 and the filter portion 1 are first solder-joined in the heater block, and then the filter body is inverted. The upper case 4 may be soldered to the same heater block, or the lower heater block and the upper heater block may be sandwiched at the same time for soldering. In addition, cases 3 and 4 described above
Various modifications such as forming a solder layer by plating in advance are possible.

As described above, in the surface mount type dielectric filter of the present invention, the capacitive substrate 2 is provided in a part of the upper case 3.
Since the segmented bodies 42a, 42b that come into contact with the upper end surface Y of the are provided, the lead portions 24b, 25b of the input / output lead terminals 24, 25 extending from the capacitance substrate 2 are connected to the ground terminals 32 ... In the assembly process. Because it can be easily corrected to the same plane,
The terminal correction step is not necessary after the assembly step, and the surface mount dielectric filter has high reliability.

Incidentally, in the above-mentioned embodiment, the section bodies 42a, 4a
Although 2b is formed by bending the side wall of the upper case 3 on the open end face side, it may be formed, for example, by extending a crosspiece between the two window portions 41 and bending the crosspiece. Also, the number is not limited to two.

Although one substrate 21 has been described as the capacitance substrate 2, separate capacitance substrates are arranged for the resonator 1a and the resonator 1e, respectively, and cut so as to abut the upper end surface of each capacitance substrate. The bodies 42a and 42b may be provided. Further, at least the input / output capacitors C _in and C are provided on the capacitor substrate 2.
are those having _out, and an inductance component in place of the slit coupling capacitance between the electrodes, also a coupling capacitance K may be formed by the capacitor substrate 2.

Also, the number of resonators constituting the filter section is not limited to five, and any number of resonators can be used according to the filter characteristics. It may be a filter having a resonator built in the body block, or may be a filter having a triplate resonator in which a strip-shaped conductor film is sandwiched between dielectric substrates.

[0039]

As described above, according to the surface mount type dielectric filter of the present invention, the input / output lead terminal extending from the capacitor substrate and the ground terminal extending from the lower case can be set substantially on the same plane, and Since the correction can be performed during the assembly process, the surface mount type dielectric filter has high surface mount reliability and easy assembly.

[Brief description of drawings]

FIG. 1 is a perspective view of a surface-mounted dielectric filter of the present invention.

FIG. 2 is a cross-sectional view taken along the line AA of FIG.

3 is an equivalent circuit diagram of the surface-mounted dielectric filter of FIG.

FIG. 4 is a plan view showing an example of a capacitance substrate used for the surface mount type dielectric filter of the present invention.

FIG. 5 is a perspective view in the assembly process of the surface mount dielectric filter of the present invention.

FIG. 6 is a cross-sectional view in the assembly process of the surface-mounted dielectric filter of the present invention.

FIG. 7 is a cross-sectional view of a conventional surface mount dielectric filter.

[Explanation of symbols]

 10- ・ Surface-mount type dielectric filter 1 --- filter unit 1a to 1e-dielectric resonator 11- ・ Dielectric block 12- Through hole 13: Inner conductor 14: Outer conductor 15: Connection pin 15a: Pin portion 2: Capacitance substrate 21 ... .... Dielectric substrate 22a to 22f, capacitance electrodes 23a to 23d ... Lead hole 24 ... Input lead terminal 24b ... Lead portion 25 ... Output lead terminal 25b・ ・ ・ ・ ・ Lead part 3 ・ ・ ・ Lower case 32 ・ ・ ・ ・ ・ Grounding terminal 4 ・ ・ ・ ・ ・ ・ Upper case 41 ・ ・ ・ ・ ・ ・ Window part 42a, 42b ・ Section body

Claims (1)

[Claims] 1. A filter section having a plurality of dielectric resonators, a capacitance substrate having an input / output capacitance component of the dielectric resonators and arranged on the open end face side of the filter section, the filter section and the capacitance. A surface mount type dielectric filter comprising an upper case and a lower case for accommodating a substrate, wherein a ground terminal extends to the outside from the lower case and an input / output lead terminal extends to the outside from a capacitor substrate. The upper case is provided with a section body that comes into contact with the upper end surface of the capacitance substrate,
2. A surface mount type dielectric filter, wherein a tip end portion of an input / output lead terminal extending from a capacitance substrate by pressing the section body is made to be the same plane as an extending plane of the ground terminal.