JPH03262201A - Irreversible circuit element - Google Patents

Abstract

PURPOSE:To decrease number of components, to improve the productivity and to reduce the cost by forming an electrode film forming at least part of a circuit element main body into a case. CONSTITUTION:A board part 2e is integrally formed in a case 2 made of an insulating resin, and an electrode film forming a circuit element main body such as a center conductor 3 and capacitor electrodes 17a-17c for a matching circuit is formed to the board part 2e be the chemical plating method or the like. Injection molding is applied to a part of the case 2 corresponding to each electrode film of the board part 2e, each terminal 8, a ground 9 and throughholes 11, 13 by using a resin material with plating adhered thereto in order to make selective plating. Then the forming is arranged in a metallic die corresponding to the entire shape of the case 2 and a resin member to which no plating is adhered is injected into the metallic die. The case 2 is formed by two-stages of injection molding. Chemical plating treatment is applied to the case 2 to form each electrode film to the required part.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to non-reciprocal circuit elements employed as high frequency components in the microwave band, such as circulator isolators, and in particular to reducing costs by reducing the number of parts and assembly man-hours. It also relates to a structure that allows for reduction in size and weight of parts.

[Conventional technology]

In general, circulators and isolators have the function of having almost no attenuation in the signal transmission direction and large attenuation in the opposite direction, and are used, for example, in transmission circuits of mobile communication devices such as mobile phones and car phones. has been adopted. Conventionally, such an isolator has a structure shown in FIG. 7. This isolator 40 has a ferrite assembly 44 in which a pair of ferrites 43 and 43 are opposed to a plurality of center conductors 42 arranged inside a magnetic metal case 41, and a matching circuit on the inner surface of the assembly 44. A pair of dielectric substrates 45.4 on which capacitor electrodes are formed.
A pair of permanent magnets 47.47 are placed in the center hole 452.45a of each dielectric substrate 45, and a pair of permanent magnets 47.47 are brought into contact with a ground electrode formed on the outer surface of each dielectric substrate 45 via a shield plate 46.46, respectively. ing. The ferrite assembly 44 also includes three pairs of reticular center conductors 42 made of copper plates, for example.
are stacked in an electrically insulated state with an insulating sheet interposed between them, and are arranged so as to intersect each other at 120 degrees, and are sandwiched between two ferrite sheets 43. One end of a strip-shaped output terminal 48 embedded in a rectangular frame-shaped resin block 49 disposed along the inner peripheral edge of the case 41 is connected to the external lead-out portion 42a of each center conductor 42. The other end of each terminal 48 is connected to the opening 4 of the case 41.
It protrudes outward from 1a.

Here, when the above-mentioned isolator or circulator is employed in, for example, a mobile phone, there is a demand for lower cost parts, and there is also a demand for smaller and lighter parts.

[Problems to be Solved by the Invention] However, the above-mentioned conventional isolators have problems in that, due to their structure, they cannot sufficiently meet the demand for lower prices, and there are limits to miniaturization and weight reduction.

In other words, the conventional ferrite assembly assembly described above involves intersecting each center conductor alternately and sandwiching an insulating sheet between each center conductor, and the assembly is inserted into the case while being positioned. Since this work is necessary, the number of parts and assembly man-hours increase, which increases costs accordingly.

In addition, since a metal case is used, it is necessary to make the case larger and leave space between the case and the circuit elements in order to avoid short circuits due to contact with each circuit element. Become larger. Furthermore, it is difficult to reduce the weight of the metal case.

The object of the present invention was made in view of the above-mentioned conventional situation, and it is an object of the present invention to provide a non-reciprocal circuit element that can reduce the number of parts and the number of assembly steps to reduce costs, as well as realize smaller and lighter parts. It is an object.

[Means for solving problems]

The invention set forth in item 1 of the present application is such that a circuit element main body including a center conductor and a matching circuit arranged in a cross-shaped manner in an electrically insulated state is disposed in a case, and a ferrite is opposed to the center conductor, and a DC magnetic field is applied. In the non-reciprocal circuit element, the case is formed of an insulating resin, and
The present invention is characterized in that the case is coated with an electrode film constituting at least a part of the circuit element body.

In addition, the invention of item 2 is an invention in which a substrate portion is integrally formed in the case, and a center conductor is coated on the substrate portion, and a part of the center conductor is formed on one main surface of the substrate portion. At the same time, the remaining part of the center conductor is coated on the other principal surface, and the center conductors are connected to each other by a through-hole electrode penetrating the substrate portion.

Here, as the method 7 for forming the center conductor on the substrate part, there is a photo-etching method in which an electrode film is formed on both surfaces of the substrate part and unnecessary parts of the electrode film are removed, or an electroless plating method is used. Can be adopted. For example, when using the electroless plating method, a resin material to which the plating will adhere and a resin material to which the plating will not adhere are used, and the plating is first applied to the portions of the substrate where the electrode film is to be formed. Injection molding is performed using a resin material, the molded product is placed in a mold having a shape corresponding to the remaining case and the substrate portion, and a resin material to which the plating does not adhere is injected into the mold, and injection molding is performed. The case is formed by this two-step injection molding.

Thereafter, by subjecting the case to electroless plating, it is possible to form an electrode film only on the central conductor portion, for example.

[Effect]

According to the non-reciprocal circuit element of the present invention, the case is formed of an insulating resin, and for example, a substrate part is integrally formed within the case, and the electrode film constituting the circuit element body is coated on the substrate part. Therefore, it is possible to easily pattern the circuit element body such as the center conductor by electroless plating method or photoetching method, and it is possible to stack each center conductor with an insulating sheet in between and insert it into the case while positioning it. This eliminates the need for difficult assembly work. Moreover, since the substrate part is integrally formed with the case, the number of parts can be reduced compared to conventional ferrite assemblies, improving productivity and reducing costs, meeting the demand for lower prices.

Furthermore, since the case is insulative, it will not cause a short circuit even if it comes into contact with each circuit element, so the gap for preventing short circuits, which is conventionally necessary, can be omitted, and the size can be reduced accordingly. Furthermore, since the resin case of the present invention can be made smaller in weight than a metal case, the overall weight can be reduced accordingly.

〔Example〕

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

1 to 6 are diagrams for explaining a non-reciprocal circuit element according to an embodiment of the present invention. In this embodiment, a case where the device is applied to a lumped constant type isolator will be explained as an example.

In the figure, ■ is the lumped constant isolator of this embodiment. This isolator 1 is housed inside a box-shaped case 2.
A pair of ferrites 4a and 4b are arranged so as to be in contact with the center conductor 3 formed thereon, and a copper grounding plate 5.5 is arranged on the outer surface of each of the ferrites 4a and 4b. A permanent magnet 6.6 is disposed on the outer surface of the center conductor 3, and the permanent magnet 6 is configured to apply a DC magnetic field to the central conductor 3. Further, a U-shaped magnetic metal yoke 7 is attached to the case 2, and the yoke 7 closes the openings on the top and bottom surfaces of the case 2, thereby forming a magnetic closed circuit. . Note that the metal yoke 7 has a recess 7a in order to prevent a short circuit with a terminal portion, which will be described later.
is formed with a notch.

The case 2 is made of insulating resin and has a rectangular box shape consisting of first to fourth side walls 2a to 2d. Further, a substrate portion 2e is integrally formed in the center of the case 2, and the inside of the case 2 is partitioned into an upper portion and a lower portion by this substrate portion 2e. In addition, the second case of the above case 2. A terminal portion 8 and a ground portion 9 are integrally formed at both lower ends of the outer surfaces of the fourth side walls 2b and 2d, respectively. Further, a second sidewall adjacent to the first side wall 2a is provided at the lower part of the substrate portion 2e. fourth side wall 2b,
A corner part 1 extending to the bottom surface of the case 2 is located at a part of the corner with 2d.
0 is bulged, and a through hole 1) extending in the vertical direction is formed in the corner 10. The upper end of this through hole 1) penetrates the upper surface of the substrate portion 2e, and the lower end penetrates the lower surface of the terminal portion 8.

Furthermore, conical convex portions 12 are formed at three locations on the upper and lower surfaces of the substrate portion 2e to abut on and position the outer peripheral surfaces of the ferrites 4a and 4b, projecting at intervals of 20 degrees. The protruding height of the convex portion 12 is the same as that of the ferrite 4.
The thicknesses of a and 4b and the distance between them are set to -. Further, a grounding piece 5 a projecting from the outer circumferential portion of the grounding plate 5 is in contact with the upper surface of the convex portion 12 . Furthermore, the convex portion 12
A through hole 13 is formed penetrating the axis.

A part and the remaining part of the central conductor 3 divided into two parts are formed on the upper and lower surfaces of the substrate part 2e. This center conductor 3 is point symmetrical with a pair of parallel conductor pieces 3a (part of the center conductor) on the upper surface of the substrate portion 2e and the other conductor piece 3b (the remainder of the center conductor) on the lower surface. In addition, the inner ends of the conductor pieces 3a and 3b are opposed to each other with the substrate portion 2e in between, and the inner ends of the conductor pieces 3a and 3b are connected to each other by a through-hole electrode 14 formed by penetrating the substrate portion 2e. It becomes. As a result, each of the central conductors 3 has a structure in which they are electrically insulated from each other by 120 degrees, and the ferrite 4 is placed at the crossing portions on both sides.
a and 4b are facing each other.

Further, a ground electrode film 16 is formed on the lower surface of the substrate portion 2e, excluding the contact portion of the lower light 4b, and on the outer surface of each convex portion 12. The outer ends of the respective conductors 1'13b on the lower surface are connected to. Further, the ground electrode 16 extends through the through hole 13 of the convex portion 12 to the upper surface of the convex portion 12 on the blood side of the substrate portion 2eJ. ('Connected.Sa [': Yuji [-notation board 2e glue, 1.+'++, three matching circuit capacitor electrode films 17a to 17c are formed, and each electrode film The outer ends of each conductor piece 3a on the upper surface are connected to 17a to 17c.Furthermore, a chip resistor 18 is connected to the one capacitor electrode film 17a, and the resistor 18 is connected to a through-hole electrode. It is connected to the earth electrode film 16 via 19.

Furthermore, the outer surface of each terminal portion 8 and the through hole 1
) is formed with an output electrode film 20,
The electrode film 20 includes two capacitor electrode films 17b and 17c.
It is connected to the. Further, a ground electrode film 22 is formed on the outer surface of each of the ground portions 9.
2 is the second case of case 2 above. It is connected to the ground electrode film 16 on the lower surface of the substrate portion 2e through the inner surfaces of the fourth side walls 2b and 2d.

Here, the center conductor 3. Capacitor electrode film 17a-1
7C2 people, output electrode membrane 20. and earth electrode membrane 16.2
No. 2 was coated by selectively applying electroless plating. To perform this selective plating, for example, the following method can be adopted. First, of the case 2, the substrate section 2e.

Each terminal part8. The portions corresponding to the respective electrode films of the ground portion 9 and the through hole 1) 13 are injection molded using a resin material to which plating will adhere. Next, this molded product is placed in a mold corresponding to the overall shape of the case 2, and a resin material to which plating does not adhere is injected into the mold.

The case 2 is formed by such two-step injection molding. Thereafter, the case 2 is subjected to an electroless plating process to form each electrode film at each of the above-mentioned required locations.

Next, the effects of this embodiment will be explained.

The isolator 1 of this embodiment has a function of blocking reverse flow of signals, and is an essential component for mobile communication devices such as mobile phones and car phones.

According to this embodiment, the case 2 is formed of an insulating resin, and the substrate portion 2e is integrally formed within the case 2, and the center conductor 3° matching circuit capacitor electrodes 172 to 17c are formed on the substrate portion 2e. Since the electrode films constituting the circuit element body are formed, the conventional assembly work of stacking each center conductor with an insulating sheet interposed and inserting it into the case while positioning it can be eliminated. In addition, in this embodiment, the terminal portion 8 is provided in the case 2.
．． Since the ground portion 9 and the ground portion 9 are integrally formed and connected to a predetermined portion by an electrode film, a conventional terminal block can be made unnecessary.

As a result, the number of parts and assembly man-hours can be reduced compared to those using conventional ferrite assemblies and terminal blocks, and costs can be reduced.

In addition, since the case 2 is made of insulating resin, the earth plate 5
There will be no short circuit even if it comes into contact with various circuit elements such as
In addition, since the conventional terminal block is not required, the space for arranging the block and the space for preventing short circuits can be omitted.
The parts can be made smaller accordingly. Furthermore, since the case 2 can be made smaller in weight than a conventional metal case, it can be made lighter.

Furthermore, according to this embodiment, each center conductor has 32 people.

Output electrode film 20. The earth electrode film 16 etc. is connected to the electroless method 2. Since it is formed by plating, pattern formation is easy.

Furthermore, in this case, not only good electrical conductivity can be obtained, but also thermal conductivity can be lowered compared to conventional metal terminals. This is because when reflow soldering the above-mentioned component elements, it is difficult for solder heat to be transmitted to each component element, so that an adverse effect on the characteristics can be avoided and reliability in quality can be improved.

In addition, the capacitor electrode film 172~
17C, the dimensional accuracy can be improved and a more accurate capacitance value can be obtained. This solves the problem that the conventional capacitor electrode film was printed as a thick film on a dielectric substrate and then baked, which caused the electrode film to easily shift.

Furthermore, in this embodiment, since each component element such as the board part 2e and the terminal part 8 is integrally formed in the case 2, the number of soldering points can be significantly reduced compared to the conventional structure. can also improve quality.

In the above embodiment, the center conductor 3. which constitutes the circuit element main body. The capacitor electrode films 178 to 17c, the ground electrode 16, etc. are all coated on the substrate portion 2e, but in the present invention, at least a part of the circuit element body is coated on the substrate portion,
The remaining portion may be formed on the top/side wall, or it is also possible to form all of the circuit elements on the side wall of the case.

Furthermore, in the above embodiment, a case was explained using a resin material to which plating adheres and a resin material 4 to which plating does not adhere, a case was formed by two-step injection molding, and an electroless plating process was applied to the case. However, the method for forming the electrode film of the present invention is not necessarily limited to this, and may be formed by, for example, a photoetching method.

Further, in the above embodiment, the case where two ferrite permanent magnets are used is explained as an example, but in the present invention, if the required characteristics are not so high, the structure may be configured with only one ferrite permanent magnet.

Furthermore, although the above embodiment has been explained using a lumped constant type isolator as an example, the present invention can of course be applied to a distributed constant type isolator, and can also be applied to a circulator. This can be achieved by removing the connected resistor and connecting the terminal portion to the electrode film.

(Effects of the Invention) As described above, according to the non-reciprocal circuit element of the present invention, the case is formed of an insulating resin, and the electrode film constituting at least a part of the circuit element body is formed within the case. Therefore, the conventional and time-consuming assembly work can be made unnecessary, and the number of parts can be reduced. As a result, productivity can be improved and costs can be reduced, and parts can also be made smaller and lighter.

[Brief explanation of drawings]

1 to 6 are diagrams for explaining an isolator according to an embodiment of the present invention, in which FIG. 1 is an exploded perspective view of the isolator, FIG. 2 is a plan view of the case, and FIG. Its bottom view, Fig. 4 is a plan view of the isolator, Fig. 5 is a sectional view taken along the line V-V in Fig. 4, and Fig. 6 is a VI-Vl
A line sectional view, FIG. 7 is a sectional view showing a conventional isolator. In the figure, 1 is an isolator (irreciprocal circuit element), 2
2e is the case, 3.17a to 17C, and 16 are the center conductor, capacitor electrode film, and ground electrode film (
4a+4b are ferrites, and 76 is a permanent magnet.

Claims (2)

[Claims] (1) A circuit element main body including a center conductor and a matching circuit arranged in a cross shape in an electrically insulated state is arranged in a case,
In the non-reciprocal circuit element configured to have a ferrite facing the center conductor and apply a DC magnetic field, the case is formed of an insulating resin, and at least a part of the circuit element main body is configured in the case. A non-reciprocal circuit element characterized by being coated with an electrode film. (2) A substrate section is integrally formed in the case, a part of the center conductor is coated on one principal surface of the substrate section, and the remaining portion of the center conductor is coated on the other principal surface of the substrate section. 2. The non-reciprocal circuit element according to claim 1, wherein the center conductors are connected to each other by a through-hole electrode penetrating the substrate portion.