Connector module

A connector module includes a substrate including stacked magnetic layers, a first principal surface, and a second principal surface opposite to the first principal surface, a surface mount connector mounted on mounting electrodes on the first principal surface of the substrate, external mounting electrodes disposed on the second principal surface of the substrate, and inductors inside the substrate and each connected at a first end thereof to a corresponding one of the mounting electrodes and connected at a second end thereof to a corresponding one of the external mounting electrodes.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a connector module including a connector for connection to a flexible cable.

2. Description of the Related Art

A mother substrate and a sub-substrate included in an electronic device, such as an information communication device, are connected to each other by a flexible cable (flexible printed circuits (FPC)) therebetween. A problem here is that since high-frequency noise radiated from a high-frequency circuit is superimposed on signal lines of the flexible cable, the noise is superimposed on patterns on the substrates and adversely affects other circuit elements. As a solution to this, a ferrite bead (inductance element) is provided on patterns on a substrate to suppress undesired noise (see, e.g., Japanese Unexamined Patent Application Publication No. 2000-269613). Japanese Unexamined Patent Application Publication No. 2000-269613 discloses a configuration in which a ground pattern and a connector connection pattern on a substrate are connected to each other by a ferrite bead.

The technique disclosed in Japanese Unexamined Patent Application Publication No. 2000-269613 requires space to mount the ferrite bead on the substrate. This means that as the number of ferrite beads increases, the space required to mount also increases. At the same time, it is difficult to mount the ferrite bead.

SUMMARY OF THE INVENTION

Preferred embodiments of the present invention provide a connector module that eliminates the problem of mounting an inductance element and achieves space saving.

A connector module according to a preferred embodiment of the present invention includes a connector, a substrate including a plurality of magnetic layers and a first principal surface and a second principal surface opposite to each other, at least one connector connection terminal disposed on the first principal surface of the substrate, the connector connection terminal being a terminal on which the connector is mounted, at least one first external connection terminal disposed on the second principal surface of the substrate, and at least one inductance element provided inside the magnetic layers and disposed between the connector connection terminal and the first external connection terminal.

With this configuration, with the inductance element being provided inside the substrate with the connector mounted thereon, there is no need to mount a separate inductance element on a printed circuit board onto which the connector module is to be mounted. Therefore, it is not necessary to create space on the printed circuit board to mount an inductance element, and it is possible to avoid the problem of mounting it.

The connector module preferably includes a plurality of connector connection terminals, a plurality of first external connection terminals provided on the second principal surface to correspond to the respective connector connection terminals, and a plurality of inductance elements provided inside the substrate, the inductance elements each being positioned between a corresponding one of the connector connection terminals and a corresponding one of the first external connection terminals.

With this configuration, even when the number of inductance elements increases, there is no need to create space on the printed circuit board to mount each of the inductance elements, and it is possible to avoid the problem of mounting them.

Preferably, the connector connection terminals are provided at locations spaced in a predetermined direction of the first principal surface, the first external connection terminals are arranged at positions opposite the respective connector connection terminals, and the inductance elements are provided between the connector connection terminals and the first external connection terminals.

This configuration enables effective use of space and facilitates formation of a plurality of inductance elements.

The connector module may include a plurality of connector connection terminals, a plurality of first external connection terminals may be provided on the second principal surface to correspond to the respective connector connection terminals, at least one of the connector connection terminals and at least one of the first external connection terminals may be connected, with the inductance element interposed therebetween, and the at least one of the connector connection terminals and the at least one of the first external connection terminals may be connected by a wire routed along a side surface of the substrate.

With this configuration, the inductance element may be provided only where necessary.

The inductance element preferably includes a coil conductor pattern wound around a winding axis parallel or substantially parallel to a stacking direction of the magnetic layers, for example.

This configuration reduces unnecessary wire routing and facilitates formation of the inductance element.

The connector module preferably further includes a ground conductor provided in the substrate and overlapping the inductance element in a stacking direction of the magnetic layers.

In this configuration, the ground conductor overlaps the inductance element and this generates a capacitance therebetween. This capacitance and the inductance component of a wire routed to connect the ground conductor to the ground defines a filter (low pass filter). Thus, a connector module including a filter function is provided.

The ground conductor is preferably disposed between the inductance element and the first principal surface.

With this configuration, with the ground conductor positioned between the inductance element and the first principal surface, the inductance element is shielded from the connector mounted on the first principal surface.

The connector module preferably further includes a second external connection terminal disposed on the second principal surface of the substrate, and an interlayer connection conductor provided in the substrate and configured to connect the ground conductor to the second external connection terminal.

In this configuration, the interlayer connection conductor is long, because the ground conductor is provided above the inductance element (i.e., adjacent to the first principal surface). This increases the inductance component.

With various preferred embodiments of the present invention, there is no need to create space to mount an inductance element on the printed circuit board onto which the connector module is to be mounted, and it is possible to avoid the problem of mounting the inductance element.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

First Preferred Embodiment

FIG. 1is a perspective view of a connector module1according to a first preferred embodiment of the present invention.FIG. 2illustrates the connector module1mounted on a printed circuit board100.FIG. 3is a cross-sectional view of the connector module1.

The connector module1includes a surface mount connector10and a substrate11integral with each other. The surface mount connector10according to the present preferred embodiment is a female connector to and from which a male connector connected to a flexible cable10C is attached and detached. Specifically, the surface mount connector10is preferably a horizontal insertion type surface mount connector including an insertion slot10A on one side to receive the flexible cable10C and a retainer10B on the other side to retain the inserted flexible cable10C. The surface mount connector10corresponds to a “connector” according to a preferred embodiment of the present invention. The surface mount connector10may be a vertical insertion type connector, and the flexible cable10C does not necessarily need to include a connector. The flexible cable10C is preferably a multi-wire cable including a bundle of wires in the present preferred embodiment, but it may be a single-wire cable including only one wire.

The substrate11includes a plurality of magnetic layers that are stacked. Mounting electrodes11A that mount the surface mount connector10thereon are provided on one principal surface (first principal surface in the present preferred embodiment) of the substrate11. AlthoughFIG. 3shows only two mounting electrodes11A for the surface mount connector10, the surface mount connector10includes a plurality of connection terminal pins corresponding to the number of wires, and the number of mounting electrodes11A is the same as that of the connection terminal pins. In the connector module1of the present preferred embodiment, the surface mount connector10preferably includes11connection terminal pins as described below. The mounting electrodes11A are connected by solder13to the respective connection terminal pins. The mounting electrodes11A correspond to a “connector connection terminal” according to a preferred embodiment of the present invention.

External mounting electrodes11B to be mounted on the printed circuit board100are provided on the other principal surface (second principal surface in the present preferred embodiment) of the substrate11. A wiring pattern101is provided on the printed circuit board100. The connector module1is mounted on the printed circuit board100preferably by soldering the external mounting electrodes11B to the wiring pattern101. The external mounting electrodes11B preferably equal in number to the mounting electrodes11A are provided at positions opposite the respective mounting electrodes11A. The external mounting electrodes11B correspond to a “first external connection terminal” according to a preferred embodiment of the present invention.

The substrate11includes coil-shaped inductors12. The inductors12are each wound around a winding axis parallel or substantially parallel to the stacking direction of the magnetic layers. The inductors12are preferably equal in number to the mounting electrodes11A and the external mounting electrodes11B. The inductors12are each connected at a first end thereof to a corresponding one of the mounting electrodes11A and connected at a second end thereof to a corresponding one of the external mounting electrodes11B. The inductors12do not necessarily need to be included in all wires, as long as they are provided for the necessary wires. A wire provided with no inductor12may be routed from the one principal surface to the other principal surface of the substrate11by a via-hole conductor inside the substrate11, or may be routed by a side conductor along the side surface of the substrate11. As described below, to eliminate an unnecessary inductance component in a ground line or other line, the wire is preferably routed along the side surface of the substrate11.

FIG. 4is a graph showing characteristics of the inductors12included in the connector module1. The inductors12included in the connector module1configured as described above have impedance frequency characteristics shown inFIG. 4. With this connector module1, the inductors12are positioned between the surface mount connector10and the wiring pattern101on the printed circuit board100. As can be seen inFIG. 4, the value of impedance Z increases as the frequency increases, and the inductors12define and function as a low pass filter for the wires. When a ferrite material having a high loss in a high-frequency region is used for the magnetic layers, a resistance component R becomes dominant over a reactance component X in the high-frequency region. That is, the inductors12suppress high-frequency noise superimposed on signal lines of the flexible cable10C.

When the inductors12for noise suppression are provided in the substrate11to be integral with the surface mount connector10, there is no need to mount an inductance element on the printed circuit board100. Accordingly, there is no need to create space to mount an inductance element, and it is possible to avoid the trouble of mounting an inductance element.

The substrate11and the inductors12of the connector module1are illustrated in a simplified manner inFIG. 3. A detailed description of the substrate11and the inductors12is provided below.

FIGS. 5 and 6illustrate magnetic layers to be stacked to define the substrate11according to the present preferred embodiment.

The substrate11is preferably formed by stacking rectangular or substantially rectangular magnetic layers111,112,113,114,115,116,117, and118in order. In the following description, the magnetic layer111stacked as above is described as an upper side. The upper principal surface of the magnetic layer111is a principal surface on which the surface mount connector10is mounted. The lower principal surface of the magnetic layer118is a principal surface mounted on the printed circuit board100. Note that the same principal surfaces of the magnetic layers111to118are not shown inFIGS. 5 and 6. Specifically, the upper principal surfaces of the magnetic layers111to116and the lower principal surfaces of the magnetic layers117and118are shown inFIGS. 5 and 6.

First, ground lines provided in the substrate11will be described.

Ground electrodes G1are provided on the magnetic layer111. Ground connection terminal pins of the surface mount connector10are connected to the ground electrodes G1. Ground electrodes G2are provided on the magnetic layer112. The ground electrodes G2are arranged at positions overlapping the respective ground electrodes G1on the magnetic layer111in plan view, and connected by via-hole conductors to the ground electrodes G1. The ground electrodes G2partially extend to, and are exposed from, respective sides of the magnetic layer112.

Side electrodes G3, G4, G5, and G6are provided on corresponding sides of the magnetic layers113,114,115, and116. The side electrodes G3are connected to the respective portions of the ground electrodes G2exposed from the respective sides of the magnetic layer112. The side electrodes G4are connected to the respective side electrodes G5, which are connected to the respective side electrodes G6.

Ground electrodes G7are provided on the magnetic layer117. The ground electrodes G7are partially exposed from respective sides of the magnetic layer117, and the exposed portions are connected to the respective side electrodes G6. Ground outer electrodes G8are provided on the magnetic layer118. The ground outer electrodes G8are connected by via-hole conductors to the respective ground electrodes G7. The ground outer electrodes G8are then soldered to a ground wiring pattern on the printed circuit board.

As described above, in the process of being routed from the magnetic layer111to the magnetic layer118, the ground lines are extended to the side surfaces of the substrate11(magnetic layers112to117). The substrate11is a magnetic member, and when via-hole conductors are provided inside the magnetic member and the ground lines are routed therethrough, inductance components are produced in the ground lines. Routing the ground lines on the side surfaces of the substrate11reduces or prevents the inductance components from being produced in the ground lines.

Signal lines in the substrate11will now be described.

A plurality of (for example,11in the drawing) mounting electrodes21are provided on the magnetic layer111. The mounting electrodes21are arranged at locations spaced in the direction (“predetermined direction” according to a preferred embodiment of the present invention) along the short sides of the principal surface of the magnetic layer111. Specifically, five of the mounting electrodes21are provided along one long side of the principal surface of the magnetic layer, and six of the mounting electrodes21are provided along the other long side of the principal surface of the magnetic layer, for example. The mounting electrodes21correspond to the mounting electrodes11A illustrated inFIG. 3. The connection terminal pins of the surface mount connector10are connected to the mounting electrodes21.

Electrodes22are provided on the magnetic layer112at the same or substantially the same positions as the respective mounting electrodes21in plan view. The electrodes22are connected by via-hole conductors to the mounting electrodes21.

Via-hole conductors24are provided on the magnetic layer113. The via-hole conductors24connect the electrodes22on the magnetic layer112to a plurality of coil electrode patterns25A and25B (described below) provided on the magnetic layer114.

The coil electrode patterns25A and25B are provided on the magnetic layer114. Preferably, the coil electrode patterns25A and25B are both bow-shaped, and are curved in opposite directions. First ends of the coil electrode patterns25A and25B overlap the respective mounting electrodes11A on the magnetic layer114in plan view. The via-hole conductors24on the magnetic layer113are connected to the respective first ends of the coil electrode patterns25A and25B. The first ends of the coil electrode patterns25A and25B are thus connected, by the via-hole conductors24and the electrodes22, to the respective mounting electrodes21.

A plurality of coil electrode patterns26A and26B are provided on the magnetic layer115. Preferably, the coil electrode patterns26A and26B are bow-shaped. The coil electrode patterns26A are curved in a direction opposite the coil electrode patterns25A, and the coil electrode patterns26B are curved in a direction opposite the coil electrode patterns25B. First ends of the coil electrode patterns26A are connected by via-hole conductors to the respective second ends of the coil electrode patterns25A. First ends of the coil electrode patterns26B are connected by via-hole conductors to the respective second ends of the coil electrode patterns25B.

While not shown, more than one magnetic layer114and more than one magnetic layer115are alternately stacked. The second ends of the coil electrode patterns26A and26B are connected by via-hole conductors to the respective first ends of the coil electrode patterns25A and25B on the magnetic layer114stacked below the magnetic layer115. Then, the coil electrode patterns25A and26A define coils each wound around a winding axis parallel or substantially parallel to the stacking direction of the magnetic layers. Similarly, the coil electrode patterns25B and26B define coils each wound around a winding axis parallel or substantially parallel to the stacking direction of the magnetic layers. The helical coils defined by the coil electrode patterns25A and25B and the coil electrode patterns26A and26B correspond to the inductors12illustrated inFIG. 3. Adjacent ones of the plurality of coils are wound and connected such that their magnetic fields are in phase.

Via-hole conductors27are provided on the magnetic layer116. The via-hole conductors27connect the first ends of the coil electrode patterns26A and26B on the magnetic layer115to respective electrodes28(described below) provided on the magnetic layer117.

A plurality of (for example,11in the drawing) external mounting electrodes29are provided on the magnetic layer118. The external mounting electrodes29correspond to the external mounting electrodes11B illustrated inFIG. 3, and are connected to the wiring pattern101(seeFIG. 2) on the printed circuit board100. The electrodes28are provided on the magnetic layer117at the same or substantially the same positions as the respective external mounting electrodes29in plan view. The electrodes28are connected by via-hole conductors to the external mounting electrodes29.

A plurality of (for example, four in the drawing) dummy mounting electrodes29A are provided on the magnetic layer118. Electrodes28A are provided on the magnetic layer117at the same or substantially the same positions as the respective dummy mounting electrodes29A in plan view. The electrodes28A are connected by via-hole conductors to the dummy mounting electrodes29A. With the dummy mounting electrodes29A, it is possible, for example, to improve the strength of mounting to the printed circuit board.

Stacking the magnetic layers including the electrodes thereon produces the substrate11in which the inductors are connected between the mounting electrodes21and the external mounting electrodes29. The mounting electrodes21and the external mounting electrodes29are both arranged at locations spaced in the direction along the short sides of the principal surface of the magnetic layer. This enables effective use of space in plan view and facilitates formation of a plurality of inductors.

In the present preferred embodiment, the coil electrode patterns25A,25B,26A, and26B are provided on the magnetic layers114and115such that the winding axis of each of the inductors12is parallel or substantially parallel to the stacking direction of the magnetic layers. However, the present invention is not limited to this. The electrode patterns may be provided on the magnetic layers such that the winding axis of each of the inductors12is parallel or substantially parallel to the planar direction (i.e., direction along the principal surface) of the magnetic layers. The number of turns of the coils may be appropriately changed. The number of turns of the coils can be changed by changing the number of the magnetic layers114and115that are stacked.

Although the coil electrode patterns are provided on all of the paths between the mounting electrodes21and the external mounting electrodes29corresponding thereto in the present preferred embodiment, the coil electrode patterns do not necessarily need to be provided on all of the paths. Although all of the layers of the multilayer substrate are magnetic layers in the present preferred embodiment, the uppermost and lowermost layers may be non-magnetic layers, or a non-magnetic layer may be provided in the middle of the coil electrode patterns.

Second Preferred Embodiment

FIG. 7is a cross-sectional view of a connector module2according to a second preferred embodiment of the present invention.

The connector module2includes the surface mount connector10and the substrate11integral with each other. The mounting electrodes11A are provided on one principal surface of the substrate11including a plurality of magnetic layers that are stacked, and the external mounting electrodes11B are provided on the other principal surface of the substrate11. The mounting electrodes11A are connected by the solder13to the connection terminal pins of the surface mount connector10. The external mounting electrodes11B are mounted onto the wiring pattern provided on the printed circuit board.

A ground connection electrode11C is provided on the other principal surface of the substrate11. The ground connection electrode11C is mounted on the ground wiring pattern on the printed circuit board. The ground connection electrode11C corresponds to a “second external connection terminal” according to a preferred embodiment of the present invention.

The substrate11includes the inductors12. The inductors12are each wound around a winding axis parallel or substantially parallel to the stacking direction of the magnetic layers. The inductors12are each connected at the first end thereof to a corresponding one of the mounting electrodes11A and connected at the second end thereof to a corresponding one of the external mounting electrodes11B.

A ground electrode14is provided on a magnetic layer of the substrate11. The ground electrode14is provided above the inductors12(i.e., adjacent to the mounting electrodes11A) in the stacking direction of the magnetic layers, and overlaps the inductors12in plan view. The ground electrode14is connected by a via-hole conductor15to the ground connection electrode11C. The via-hole conductor15corresponds to an “interlayer connection conductor” according to a preferred embodiment of the present invention.

In the connector module2structured as described above, a stray capacitance C1is produced between the ground electrode14and the inductors12. The via-hole conductor15includes an inductance component L1. The stray capacitance C1and the inductance component L1define an LC resonant circuit, which is connected by the ground connection electrode11C to the ground.

FIG. 8illustrates an equivalent circuit of the connector module2. The connector module2includes the stray capacitance C1and the inductance component L1as described above. Thus, as illustrated inFIG. 8, the connector module2has a configuration in which the LC resonant circuit connected to the ground is connected to the inductors12. That is, the connector module2provides a filter function (e.g., low pass filter).

Locating the ground electrode14above the inductors12increases the inductance component L1, because the distance between the via-hole conductor15and the ground connection electrode11C is long. The ground electrode14may be located below the inductors12(i.e., adjacent to the external mounting electrodes11B), and this reduces the inductance component L1.

FIG. 9illustrates frequency characteristics of an insertion loss of the connector module2according to the present preferred embodiment. For comparison, the lower graph ofFIG. 9shows frequency characteristics of a connector module that provides no filter function. As shown inFIG. 9, an attenuation pole is provided in a desired band in the frequency characteristics of the connector module2including an LC resonant circuit. The connector module2thus eliminates high-frequency noise in the desired band superimposed on signal lines between the mounting electrodes11A and the external mounting electrodes11B. For example, providing an attenuation pole at around 1.6 GHz reduces or eliminates adverse effects on cellular-band communication circuits.

The connector module2includes the mounting electrodes11A, the external mounting electrodes11B, and a plurality of signal lines. When the ground faces a portion of the coil electrode pattern in each line, a capacitive component is able to be added to each signal line. Additionally, when the ground electrode14is connected to the ground connection electrode11C by a via-hole conductor passing through the magnetic layers, the filter function is able to be added to all of the signal lines. This eliminates the need to include a plurality of inductances (L components) which are elements of the LC resonant circuit, and makes it possible to achieve space saving.

The substrate11, the inductors12, and the ground electrode14of the connector module2are illustrated in a simplified manner inFIG. 7. A detailed description of the substrate11, the inductors12, and the ground electrode14is provided below.

FIGS. 10 and 11illustrate magnetic layers to be stacked to form the substrate11according to the present preferred embodiment. The ground lines and signal lines provided on the stacked magnetic layers111to118will not be described here, as they are similar to those in the first preferred embodiment.

A ground electrode30is provided on the magnetic layer113. The ground electrode30is located at a position overlapping the coil electrode patterns25A,25B,26A, and26B on the magnetic layers114and115in plan view. The ground electrode30corresponds to the ground electrode14illustrated inFIG. 7.

Via-hole conductors31,32,33, and34are provided on the magnetic layers114,115,116, and117, respectively. A ground connection electrode35is provided on the magnetic layer118. The via-hole conductors31to34connect the ground electrode30to the ground connection electrode35. The via-hole conductors31to34correspond to the via-hole conductor15illustrated inFIG. 7. The ground connection electrode35corresponds to the ground connection electrode11C illustrated inFIG. 7, and is soldered to the ground wiring pattern on the printed circuit board.

As described above, the ground electrode30is provided on a different layer from those including the coil electrode patterns25A thereon. This arrangement simplifies the routing of electrodes on each magnetic layer. Also, since the ground electrode30is positioned between the mounting electrodes21and the coil electrode patterns25A, the coils (corresponding to the inductors12) defined by the coil electrode patterns25A are shielded from the mounting electrodes21.

As described above, the substrate11is preferably formed by stacking the magnetic layers including the electrodes provided thereon.

Although the ground electrode14is disposed above the inductors12in the present preferred embodiment, the ground electrode14may be provided both above and below the inductors12to increase the stray capacitance C1. The shape of the coil electrode patterns defining the inductors12may be modified to increase the stray capacitance C1.

FIG. 12illustrates an example in which the shapes of coil electrode patterns are modified to increase the stray capacitance C1.

In this example, a rectangular or substantially rectangular electrode17is provided between the ground electrode14and the coil electrode pattern25A. The electrode17may be provided on an additional magnetic layer stacked between the magnetic layers113and114. When the ground electrode14is provided on the upper principal surface of the magnetic layer113, the electrode17may be provided on the lower principal surface of the magnetic layer113. When the coil electrode pattern25A is provided on the lower principal surface of the magnetic layer114, the electrode17may be provided on the upper principal surface of the magnetic layer114.

The electrode17is connected by a via-hole conductor to the mounting electrode21and the coil electrode pattern25A. The electrode17then defines a coil (corresponding to the inductors12) together with the coil electrode patterns25A and26A. That is, the electrode17defines a portion (one end) of the coil. The stray capacitance C1is increased in this case, because the area in which the ground electrode14and the electrode17face each other is greater than the area in which the ground electrode14and the coil electrode pattern25A face each other.