JPH0897609A - Dielectric filter and manufacturing method thereof - Google Patents

Abstract

PURPOSE: To prevent leaked electric field from an open end side of a dielectric resonator by applying solder plating in advance to a prescribed part of a metallic case in order to selectively solder a part in the vicinity of the open end of an outer conductor of a dielectric resonator and the metallic case. CONSTITUTION: A dielectric resonator 1 made of a cylindrical ceramics dielectric material has a center hole 11 in its lengthwise direction and a metallic film inner conductor 12 is formed to the inner face. A metallic film outer conductor 13 is formed similarly to the entire faces except an open end face 14 of an outer side face. Solder plating 62 is applied in advance to the metallic case 2 so that a part around the vicinity of the open end 141 of the outer conductor 13 of the resonator 1 is selectively soldered. Furthermore, a high heat resistant epoxy group adhesives 7 is applied to a part around the end of the case 2 close to a short-circuited end 15 opposite to the open end 14 so that soldering and adhesion are conducted simultaneously. As a result, leakage of an electric field from the open end 14 of the resonator 1 is prevented and components are assembled efficiently without degrading the quality.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dielectric filter used for communication electronic equipment and the like and a method for manufacturing the same.

[0002]

2. Description of the Related Art Typical examples of conventional dielectric filters are shown in FIGS. A conventional dielectric filter is a circuit in which dielectric resonators 1a, 1b, 1c and 1d, a metal case 2 that covers almost the entire dielectric resonator, and a metal case and the dielectric resonator are electrically shielded. A wiring board 3 in which both the wiring surface and the ground surface are covered with copper foil, an input / output terminal 4,
It is composed of a circuit component 8 such as a coil and a capacitor. The metal case 2 has one or more holes, for example, in FIG.
5c and 5d are formed.

Dielectric resonators 1a, 1b, 1c, 1d,
The wiring board 3, the input / output terminal 4 and the circuit component 8 are electrically or mechanically connected to predetermined positions, and the metal case 2 is covered so as to cover the whole of them, and the holes 5a, 5b, 5 are formed.
They are joined to each other by using a method such as pouring solder from c and 5d.

In the above-mentioned conventional technique, the metal case 2 and the dielectric resonators 1a, 1b, 1c, 1d are manually soldered, so that there is a problem that the efficiency of the assembling work is low. Further, the holes 5a, 5b, 5 are formed in the metal case 2.
It takes time and cost to open c and 5d. Furthermore, as shown in FIG. 6, solder 6 is formed around the hole 5b.
However, there are drawbacks such as the adherence of solder, the formation of protrusions due to solder, the increase in size in the thickness direction, and difficulty in making the height constant.

On the other hand, in order to improve these problems,
As shown in FIG. 7, it is also possible to apply cream solder 61 to the surface of the metal case 2 that is to be joined to the dielectric resonator in advance, and after the placement of the cream solder 61 is completed at a predetermined location, heat the whole to join. Although the efficiency of the assembly work is improved, as shown in FIG.
As shown in FIG. 3, the entire surface between the dielectric resonator 1 and the metal case 2 is bonded, and due to the difference in the coefficient of thermal expansion between the bonded resonators, excessive thermal stress is generated, and the dielectric resonator 1
There is a problem that the outer conductor 13 is cracked or peeled off.

[0006]

SUMMARY OF THE INVENTION The present invention has sufficient electrical connection and mechanical strength to join the outer conductor of the dielectric resonator and the metal case covering the dielectric resonator. ,
An object of the present invention is to provide a dielectric filter having a low assembly height and a method for manufacturing the same.

[0007]

SUMMARY OF THE INVENTION In order to overcome the above-mentioned drawbacks of the prior art, the present invention provides a dielectric resonator near an open end of a dielectric resonator electrically or mechanically connected to a wiring board. Selectively solder one end of the container to the metal case,
In order to avoid excessive heat stress while electrically connecting the dielectric resonator to the ground with reliable conductivity, the other end of the dielectric resonator should be It is characterized in that sufficient mechanical strength is maintained by joining with an adhesive.

That is, according to the present invention, a cylindrical ceramic dielectric material is used, and a through hole is formed in the center portion, an inner conductor is formed on the inner surface of the center hole, and an open end surface is formed on one end surface. The dielectric resonator includes an outer conductor formed on the entire side surface, a wiring substrate electrically and mechanically connected to the dielectric resonator, and a metal case covering the dielectric resonator to cover the entire dielectric resonator. A portion of the outer conductor of the body resonator near the open end is selectively soldered to a metal case to electrically connect it, and a portion of the outer conductor of the dielectric resonator near the short-circuit end and the metal case are made of a resin adhesive. It is a dielectric filter characterized by being mechanically joined by using.

The present invention has a structure in which only the portion near the open end of the dielectric resonator, the input / output terminal connecting the dielectric resonator and the wiring board, and the circuit component element in the wiring board are selectively covered. It is the dielectric filter described above, which is made of a metal case.

The present invention is characterized in that a predetermined portion of the metal case is preliminarily solder-plated in order to selectively solder the portion near the open end of the outer conductor of the dielectric resonator and the metal case. It is a method for manufacturing the dielectric filter described above.

According to the present invention, in order to selectively solder an outer conductor near the open end of a dielectric resonator and a metal case,
In the method of manufacturing the dielectric filter described above, cream solder is applied in advance to a predetermined portion of the metal case.

[0012]

According to the present invention, the protrusion of solder on the outer surface of the metal case does not occur, and no excessive thermal stress is applied between the dielectric resonator and the metal case. It is possible to reliably ground the portion of the outer conductor near the open end of the resonator, and even if the portion near the open end of the dielectric resonator is partially soldered, the other end of the dielectric resonator should be By using the resin adhesive, the mechanical strength can be sufficiently ensured and the assembling efficiency can be improved. Furthermore, when the metal case of the present invention is used, it is possible to widen the range of frequency adjustment in addition to reducing the cost of parts.

[0013]

Embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1) FIG. 1 is an exploded perspective view showing an embodiment of the dielectric filter of the present invention, and FIG. 2 is a sectional view after assembly thereof.

As shown in FIGS. 1 and 2, a dielectric resonator 1 made of a cylindrical ceramic dielectric material has a central hole 11 extending in the longitudinal direction at the center of the end face, and an inner surface of the central hole 11 is formed. An inner conductor 12 made of a metal film is formed, and an outer conductor 13 also made of a metal film is formed on the entire outer surface except the open end 14 surface. Solder plating 62 is applied to the metal case 2 in advance so that the vicinity of the open end 14 of the outer conductor 13 of the dielectric resonator 1 is selectively soldered. Further, a resin adhesive 7 is applied near the end of the case near the short-circuit end 15 on the opposite side of the open end 14. In the present invention, a high heat resistant epoxy adhesive is used so that the soldering work and the bonding work can be performed at the same time.

Dielectric resonators 1a, 1b, 1c, 1d,
After the input / output terminal 4 and the circuit constituent element 8 are electrically and mechanically connected to a predetermined position of the wiring board 3, as shown in FIG. 2, the metal case 2 is covered and the whole is heated. By doing so, electrical connection by solder and mechanical joining by an adhesive can be achieved at the same time.

In this embodiment, all the steps of connecting the wiring board 3, the dielectric resonator 1, the input / output terminals 4 and attaching the metal case 2 are preliminarily performed using cream solder and a high heat resistant epoxy resin. It is also possible to perform the heating only once, thereby reducing the thermal stress applied to each component and improving the work efficiency.

(Embodiment 2) FIG. 3 is an exploded perspective view showing another embodiment of the dielectric filter of the present invention, and FIG. 4 is a sectional view after the assembly. As shown in FIGS. 3 and 4, the metal case 2 includes a portion near the open end (the left end surface of FIG. 3) of the outer conductor 13 of the dielectric resonator 1, the input / output terminal 4, and the circuit component portion of the wiring board 3. It is shaped so as to cover selectively. Further, cream solder 61 is applied so that the vicinity of the open end 14 of the outer conductor 13 of the dielectric resonator 1 is selectively soldered, and the end portion of the metal case 2 is provided with the first embodiment. Similarly, a high heat resistant epoxy resin adhesive 7 was applied.

After the dielectric resonators 1a, 1b, 1c, 1d, the input / output terminal 4 and the circuit component 8 are electrically and mechanically connected to predetermined positions of the wiring board 3, these are connected to the metal. The case 2 is covered as shown in FIG. 4, and the whole is heated to electrically connect the outer conductor of the dielectric resonator and the metal case with solder, and the dielectric resonator and the metal case with a resin adhesive. The mechanical joining of is performed at the same time.

In the second embodiment, the dielectric resonator 1a,
1b, 1c, 1d are in a state of being electrically shielded by the outer conductor formed in the dielectric resonator itself, except for the portion near the open end 14. Since the electric field leaks from the open end portion, it is important to electromagnetically shield this vicinity portion.However, by adopting the configuration of the embodiment, the electromagnetic shielding and the grounding effect of the open end portion can be obtained. To be Thus, many parts of the dielectric resonator are
With the structure that the metal case is not covered, fine adjustment of the center frequency, which was conventionally done only near the short-circuit end or by providing a hole in the metal case, is extremely easy and easy to adjust. It is possible to widen the width of.
Further, since the metal case itself becomes small and it is not necessary to form a hole for frequency adjustment, the structure is simplified and the cost of parts is reduced.

Although the embodiment of the present invention has been described as an example of a dielectric filter in which four dielectric resonators are combined, the present invention is limited to a dielectric filter having only four dielectric resonators. It goes without saying that the number of dielectric resonators is not limited.

[0022]

According to the present invention, sufficient electrical connection and mechanical strength are satisfied for joining the outer conductor of the dielectric resonator and the metal case covering the dielectric resonator, and assembly is performed. A dielectric filter having a low height and a manufacturing method thereof can be provided.

[Brief description of drawings]

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

FIG. 2 is a sectional view after assembling of the first embodiment of the dielectric filter of the present invention.

FIG. 3 is an exploded perspective view showing a second embodiment of the dielectric filter of the present invention.

FIG. 4 is a sectional view of the second embodiment of the dielectric filter of the present invention after assembly.

FIG. 5 is an exploded perspective view showing a conventional dielectric filter.

6 is a cross-sectional view after assembly of the conventional dielectric filter shown in FIG.

FIG. 7 is an exploded perspective view showing another example of a conventional dielectric filter.

8 is a sectional view of another example of the conventional dielectric filter shown in FIG. 7 after assembly.

[Explanation of symbols]

 1, 1a, 1b, 1c, 1d Dielectric resonator 2 Metal case 3 Wiring board 4 Input / output terminals 5a, 5b, 5c, 5d Holes (for solder injection) 6 Solder 7 Adhesive 8 Circuit component 11 Center hole 12 Inner conductor 13 Outer conductor 14 Open end 15 Short-circuited end 61 Cream solder 62 Solder plating

Claims (4)

[Claims] 1. A cylindrical ceramic dielectric material,
A dielectric resonator having a through hole in the center, an inner conductor on the inner surface of the center hole, and an open end surface on one end surface, and an outer conductor formed on the entire outer surface excluding the open end surface, and the dielectric resonator. A wiring board electrically and mechanically connected to each other, and a metal case that covers the entire dielectric resonator so as to surround the dielectric resonator, and selectively solders a portion near the open end of the outer conductor of the dielectric resonator to the metal case. A dielectric filter, characterized in that it is attached and electrically connected, and a portion of a dielectric resonator near a short-circuit end and a metal case are mechanically joined together by using a resin adhesive. 2. A metal case configured to selectively cover only a portion near the open end of the dielectric resonator, an input / output terminal connecting the dielectric resonator and the wiring board, and a circuit component in the wiring board. The dielectric filter according to claim 1, wherein the dielectric filter comprises: 3. The solder plating is applied to a predetermined portion of the metal case in advance in order to selectively solder the portion near the open end of the outer conductor of the dielectric resonator and the metal case. 1. The method for manufacturing a dielectric filter according to 1. 4. A cream solder is applied in advance to a predetermined portion of the metal case in order to selectively solder the portion near the open end of the outer conductor of the dielectric resonator and the metal case. Item 2. A method of manufacturing a dielectric filter according to item 1.