JP4605501B2 - Non-reciprocal circuit element - Google Patents

Description

  The present invention relates to a nonreciprocal circuit device having a nonreciprocal transmission characteristic with respect to a high-frequency signal, and more particularly to an improvement of a lower case that accommodates a multilayer substrate incorporating a plurality of capacitance elements.

  Conventionally, there are non-reciprocal circuit elements such as isolators and circulators as one of transmission / reception circuit components such as mobile phones and automobile phones used in the microwave band and UHF band. In general, an isolator or a circulator is used for the purpose of preventing the amplifier from being damaged, and has a function of reducing the insertion loss in the signal transmission direction and increasing the reverse loss in the reverse direction. Hereinafter, the present specification will be described by taking an isolator as an example of the non-reciprocal circuit device.

FIG. 11 is an exploded perspective view showing an example of a conventional isolator. This isolator is a metal case which serves as a magnetic yoke (upper case 1, the lower case 30), the permanent magnet 2, the central conductor assembly 20, incorporating a plurality of capacitance elements, the upper surface lamination, the electrode pattern on the bottom surface is formed A substrate 15 and a resistance element (not shown) are provided. In this conventional example, the center conductor assembly 20 has a structure in which the center conductor is laminated on the garnet ferrite (ferrimagnetic material) with an electrode pattern, but is also punched into a predetermined shape or etched. There is also a configuration in which a copper thin plate formed in this manner is wound around garnet ferrite.

FIG. 12 is a plan view of a lower case constituting a conventional isolator. This lower case is made of a resin such as a ground electrode, external terminals IN, OUT, GND , a lower case that constitutes the wall portion 25 to be erected, and engineering plastic (shown by hatching in the figure) with heat resistance. It is configured by insert molding, and has external terminals IN, OUT, and GND for connection to a mounting substrate, and is configured to be surrounded by walls formed by the resins 35 and 36 on all sides. .
An electrode pattern for connection with the lower case is formed on the lower surface of the multilayer substrate 15, and the multilayer substrate is placed on the ground electrode that appears on the inner bottom surface of the lower case to which the solder paste is applied. , a multilayer substrate 15 and the lower case is soldered by a solder re flow. Further, the electrode pattern 17 formed on the upper surface of the multilayer substrate 15 and the center conductor (not shown) of the center conductor assembly 20 are appropriately soldered.

JP 2003-204207 A

  As mobile phones become smaller and more multifunctional, nonreciprocal circuit elements are also strongly required to be smaller. The embodiment of Patent Document 1 discloses a non-reciprocal circuit element having an outer dimension of 5 mm × 5 mm × 2 mm, but at present, a small non-reciprocal circuit element having an outer dimension of 4 mm × 4 mm × 1.7 mm is disclosed. Non-reciprocal circuit elements having outer dimensions of 3.2 mm × 3.2 mm × 1.6 mm have also been proposed. As such nonreciprocal circuit elements are miniaturized, components such as the upper and lower cases, the central conductor assembly, and the multilayer substrate are also miniaturized.

The input / output terminal and ground terminal formed on the lower case are preferably formed in as wide an area as possible from the viewpoint of ensuring connection reliability against vibration, impact, or deformation. The area must be reduced. Particularly, since the input / output terminals are only held by the resin constituting the resin wall portion of the lower case, a strong mechanical holding force cannot be expected. For this reason, when the input / output terminals are reduced in area, the input / output terminals may fall out of the lower case when the nonreciprocal circuit element is solder-mounted on a circuit board and used for a bending test or the like.
Therefore, an object of the present invention is to provide an irreversible circuit element having excellent connection reliability against vibration, impact, or deformation by configuring the input / output terminals in a shape that is difficult to drop off from the lower case.

According to a first aspect of the present invention, there is provided a substantially box-shaped housing that accommodates a central conductor assembly in which a plurality of central conductors are arranged on a ferrimagnetic body, and a multilayer substrate on which a plurality of capacitance elements constituting a resonance circuit with the central conductor is formed. A nonreciprocal circuit device comprising a lower case, a permanent magnet that applies a DC magnetic field to the ferrimagnetic material, and an upper case that houses the permanent magnet, wherein the lower case includes a lower surface portion and the lower surface portion A magnetic yoke part constituting two yoke wall parts rising and facing each other and a resin wall part constituting the remaining two wall parts, each of the resin wall parts having a plurality of ground terminals and the ground terminal An input / output terminal is formed between the terminals, and a part of the resin constituting the resin wall extends to the lower surface side of the lower case to hold the input / output terminal and to be continuous with the input / output terminal. Connected to the ground terminal It is exposed to the same plane magnetic yoke section as the inner bottom surface of the lower case that, said central conductor and the terminal portion and the magnetic yoke portion electrically connected to the electrode pattern of the multilayer substrate, wherein the terminal portion, the lower comprising a first major surface appearing inside bottom of the case to connect the input and output electrodes of the multilayer substrate, and the second major surface is the table on the back surface of the lower case, the side surfaces connecting between these main surfaces The side surface of the terminal portion includes a stepped portion and / or an inclined portion and is covered with a resin constituting the resin wall portion, and the first main surface side of the terminal portion is more than the second main surface side. A nonreciprocal circuit device having a large area .

  In the present invention, it is preferable that the terminal portion is formed wider on the inner bottom surface side of the lower case than on the rear surface side of the lower case.

  According to the present invention, it is possible to provide an irreversible circuit element that is excellent in connection reliability against vibration, impact, or deformation by configuring the input / output terminals in a shape that does not easily drop from the lower case.

A nonreciprocal circuit device according to an embodiment of the present invention will be described in detail below.
1 is an external view of a non-reciprocal circuit device according to an embodiment of the present invention, FIG. 2 is an exploded perspective view thereof, FIG. 3 is a plan view of a lower case, and FIG. 4 is a back surface of the lower case. FIG. In FIG. 1 to FIG. 4, hatched portions indicate portions made of resin. 5 to 7 are external views of the input / output terminals, and FIGS. 8 to 10 are views for explaining a method of manufacturing the lower case.

First, a method for manufacturing the lower case 30 will be described with reference to FIGS. The long sheet material made of a magnetic metal material, punched into a predetermined shape by press working machine, as shown in FIG. 8, a portion of the lower case at the distal end of the plurality of supporting portions 53 which connects the hoops 60 The magnetic yoke portion to be formed is integrally formed.
Thereafter, by bending the predetermined portion in the mold, as shown in FIG. 9, to form two walls 25 facing erected from the magnetic yoke portion forming the lower surface of the lower case. The tip of the other support part 54 is formed separately from the magnetic yoke part. The support 54 constitutes an input / output terminal of the non-reciprocal circuit element when the lower case is used.
In the middle of the support portions 53 and 54, a portion whose width is narrowed is formed. In the subsequent process, the narrow portion is separated from the hoop 60. By separating the narrow portion in this way, the area where the metal surface of the magnetic yoke portion is exposed is minimized, and oxidation of the exposed portion is reduced. is doing.

The magnetic metal material constituting the hoop 60 is excellent in magnetic properties such as SPCC, 42Ni · Fe alloy, 45Ni · Fe alloy, Fe-Co alloy, etc., and these metal materials are cold to about 100 to 300 μm. Rolled or hot rolled. Since the magnetic yoke portion is used as a part of the magnetic circuit, it is preferable to select a magnetic material having excellent magnetic characteristics. As for the magnetic properties, the maximum permeability is 5000 or more and the saturation magnetic flux density is 0.6 Tesla or more, preferably 1.4 Tesla or more. If such a magnetic material is selected, when a nonreciprocal circuit element is miniaturized, even if a thin plate having a thickness of 160 μm or less is used, the leakage of magnetic flux can be reduced, and a necessary and sufficient DC magnetic field can be applied to garnet ferrite. Can be given.
In addition, a highly conductive metal film having an electrical resistivity of 5.5 μΩ · cm or less made of a metal or alloy containing at least one of silver, copper, gold, and aluminum is formed on the surface. The film thickness at this time is 0.5 to 25 μm. The magnetic yoke also functions as a ground, but with this configuration, the metal film serves as a path to the ground terminal for high-frequency current, thereby improving the transmission efficiency of high-frequency signals and suppressing mutual interference with the outside. Loss can be reduced.
Among highly conductive metal films, silver has excellent properties such as good solderability, low contact resistance, and low cost compared to gold. However, the silver surface is very active and has a tendency to adsorb on the surface. Discoloration easily occurs due to reaction with corrosive media such as moisture. This discoloration film impairs the solderability and increases the contact resistance. For this reason, it is preferable to form a protective film such as an organic chelate film on the silver surface to protect the silver surface.

Sprocket holes 52 are provided in the hoop 60 at predetermined intervals, and the hoops 60 are sequentially fed into the injection mold by the sprocket. A resin such as liquid crystal polymer and polyphenylene sulfide is injected into the magnetic yoke portion disposed in the injection molding machine, and insert molding is performed . As shown in FIG. Two wall portions 35 were formed . Further, in the post-process, the lower case 30 is formed by integrating the magnetic yoke portion and the input / output terminals by separating from the hoop 60 at the narrow portion .

As shown in the plan view of FIG. 3, the lower case 30 has terminal portions TT1, TT2 continuous with the input / output terminals IN and OUT and a magnetic yoke portion continuous with the ground terminal GND exposed on the inner bottom surface thereof. The inner bottom surface of the lower case 30 is formed on the same plane with the magnetic yoke portion, the terminal portions TT1 and TT2, and the resin supporting the terminal portion.
5 to 7 show external views of the input / output terminals. The terminal portions TT1 and TT2 corresponding to the tip portions of the input / output terminals are formed so that the side that appears on the inner bottom surface of the lower case is wider than the side that appears on the back surface of the lower case. Specifically, the side surface of the terminal portion forms a step as shown in FIG. 5, forms a slope as shown in FIG. 7 , or forms a step as shown in FIG. In addition to forming a slope to form a shape that does not easily fall off, the area covered with the resin is increased to improve the mechanical holding force.

  The lower case 30 formed in this manner is sequentially conveyed through the assembly steps while being connected to the hoop using the sprocket holes 52. In the next step, solder is applied to the terminal portions TT1 and TT2 that are continuous with the input / output terminals IN and OUT of the lower case 30 and the magnetic yoke portion that is continuous to the ground terminal GND, and then a multilayer substrate in which a plurality of capacitors are integrated is disposed. did.

The multilayer substrate 15 is formed by printing an electrode pattern for forming a capacitance element on a dielectric ceramic green sheet and laminating the electrode patterns so as to oppose each other as appropriate, thereby forming a plurality of capacitance elements having a predetermined capacitor capacity. It will be. The ceramic green sheets are laminated and pressure-bonded to form a laminated body and then fired to form a laminated substrate 15. The electrode inside the multilayer substrate is formed by simultaneous firing with ceramic. In this laminated substrate, electrodes extending over different layers are electrically connected by via electrodes formed in the substrate. A plurality of electrode patterns 17 are formed on the upper surface of the multilayer substrate 15, and the resistors 11 are formed between the electrode patterns by printing and baking methods.

In addition, on the lower surface of the multilayer substrate 15, that is, on the connection surface with the inner bottom surface side of the lower case, input / output electrodes connected to the terminal electrodes TT <b> 1 and TT <b> 2 formed on the lower case 30, A grounding electrode connected to a magnetic yoke portion continuous with the ground terminal GND formed in the lower case is formed in a region including the center portion. Since the inner bottom surface side of the lower case is formed wider than the back surface side of the lower case, the terminal portion can be easily connected to the input / output electrodes of the multilayer substrate 15 and can be vibrated or shocked. The connection strength against deformation can be improved.
Further, the ground electrode is placed so as to contact the large area relative to the inner bottom surface of the lower case 30. With this configuration, the distribution of the high-frequency current on the inner bottom surface of the lower case 30 is made uniform, and the electrical characteristics are stabilized.

  Next, solder is applied to the electrode pattern 17 formed on the upper surface of the multilayer substrate 15, placed on the central conductor assembly 20 composed of the central conductors 5 and 6 and the garnet ferrite 3, and solder reflowed. 15, contact portions of the lower case 30 and the central conductor assembly 20 were mechanically and electrically connected. In this embodiment, since the electrode pattern 17 can be formed up to the very vicinity of the outer peripheral edge of the multilayer substrate 15, the formation area can be further increased. Of course, the resistor 11 can be mounted on the electrode pattern 17 together with the central conductor assembly 20 as a chip resistor.

Next, the upper case 1 in which the permanent magnet 2 was disposed so as to apply a DC magnetic field to the central conductor assembly 20 was put on the lower case 30.
The upper case 1 is formed by punching out a long sheet material made of a magnetic metal material into a predetermined shape with a press machine and bending it with a die, as with the lower case 30, so that an upper surface portion and four walls are formed. A slit portion 22 that is continuous in the height direction is formed at the ridge portion of the adjacent side surface. The upper case 1 is put on the lower case 30 together with the slit portion 22 and the resin columnar portion 26 of the lower case 30.

  Thereafter, the connecting portions 53 and 54 of the long hoop 60 were cut to obtain the nonreciprocal circuit device shown in FIG. In this embodiment, the non-reciprocal circuit element is assembled in the state of the hoop 60. However, after forming the lower case, the connecting portions 53 and 54 may be cut and assembled using the individual lower cases. Needless to say.

  According to the present invention, it is possible to provide an irreversible circuit element that is excellent in connection reliability against vibration, impact, or deformation by configuring the input / output terminals in a shape that does not easily drop from the lower case.

1 is a perspective view of a non-reciprocal circuit device according to an embodiment of the present invention. 1 is an exploded perspective view of a non-reciprocal circuit device according to one embodiment of the present invention. It is a top view of the lower case used for the nonreciprocal circuit device based on one Example of this invention. It is a reverse view of the lower case used for the nonreciprocal circuit device based on one Example of this invention. BRIEF DESCRIPTION OF THE DRAWINGS It is an external view of the input / output terminal of the lower case used for the nonreciprocal circuit device based on one Example of this invention, (a) Top view, (b) Side view, (c) Front view. BRIEF DESCRIPTION OF THE DRAWINGS It is an external view of the input / output terminal of the lower case used for the nonreciprocal circuit device based on one Example of this invention, (a) Top view, (b) Side view, (c) Front view. BRIEF DESCRIPTION OF THE DRAWINGS It is an external view of the input / output terminal of the lower case used for the nonreciprocal circuit device based on one Example of this invention, (a) Top view, (b) Side view, (c) Front view. It is a figure which shows the assembly state of the lower case used for the nonreciprocal circuit device based on one Example of this invention. It is a figure which shows the assembly state of the lower case used for the nonreciprocal circuit device based on one Example of this invention. It is a figure which shows the assembly state of the lower case used for the nonreciprocal circuit device based on one Example of this invention. It is a disassembled perspective view of the conventional nonreciprocal circuit device. It is a top view of the lower case used for the conventional nonreciprocal circuit device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Upper case 2 Permanent magnet 3 Garnet ferrite 5, 6, 7 Center conductor 12 Lower case 15 Laminated substrate 20 Central conductor assembly 28 Resin protrusion 35, 35 Resin wall TT1, TT2 Terminal part IN, OUT Input / output terminal

Claims (1)

A center conductor assembly in which a plurality of center conductors are arranged on a ferrimagnetic body; a substantially box-shaped lower case that houses a laminated substrate on which a plurality of capacitance elements that constitute a resonance circuit with the center conductors; A nonreciprocal circuit device comprising a permanent magnet for applying a DC magnetic field to a magnetic body, and an upper case for housing the permanent magnet,
The lower case includes a lower surface portion thereof, a magnetic yoke portion constituting two yoke wall portions rising from and opposed to the lower surface portion, and a resin wall portion constituting the remaining two wall portions,
Each of the resin wall portions includes a plurality of ground terminals and an input / output terminal sandwiched between the ground terminals, and a part of the resin constituting the resin wall portion extends to the lower surface side of the lower case. The input / output terminal is held, the terminal portion continuous with the input / output terminal, the magnetic yoke portion continuous with the ground terminal are exposed on the same plane as the inner bottom surface of the lower case, and the central conductor and the terminal portion The magnetic yoke part is electrically connected by the electrode pattern of the laminated substrate,
The terminal portion has a first major surface to connect the input and output electrodes of the multilayer substrate appearing on the inside bottom surface of the lower case, and the second major surface is the table on the back surface of the lower case, between the main surface The side surface of the terminal portion is provided with a stepped portion and / or an inclined portion, and is covered with a resin constituting the resin wall portion, and the first main surface side of the terminal portion is the second side. A non-reciprocal circuit device characterized by having a larger area than the main surface side .

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