Patent ID: 12225661

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

First Preferred Embodiment

A multilayer substrate according to a first preferred embodiment of the present invention will be described with reference to the drawings.FIG.1is an external perspective view of a multilayer substrate10according to the first preferred embodiment of the present invention.FIG.2is an exploded plan view of the multilayer substrate10according to the first preferred embodiment of the present invention.FIG.3Ais a cross-sectional view in a first region of the multilayer substrate10according to the first preferred embodiment of the present invention, andFIG.3Bis a cross-sectional view in a second region of the multilayer substrate10according to the first preferred embodiment of the present invention.FIG.4is a side cross-sectional view of the multilayer substrate10according to the first preferred embodiment of the present invention. In each of the drawings in the following preferred embodiments, the vertical and horizontal dimensional relationship is emphasized as appropriate, and does not always match the actual vertical and horizontal dimensional relationship. In order to make the drawings easy to see, some reference signs are omitted. In addition, inFIG.2, wiring in the stacking direction (a Z-axis direction) is the same or substantially the same at both ends.

As shown inFIG.1,FIG.2,FIGS.3A and3B, the multilayer substrate10includes an insulator110that includes a first region and a second region, terminal electrodes211and212, connection electrodes221and222, a first signal line310, and a second signal line320. The first region and the second region of the insulator110have a flat plate shape.

The second region of the insulator110is located at a position between two first regions, and a thickness of the second region is smaller than a thickness of the first region (a length in the stacking direction is small). In other words, the thickness H2of the second region of the insulator110is smaller than the thickness H1of the first region of the insulator110(H1>H2).

The first region of the insulator110includes a first main surface151on one side of the insulator110and a second main surface152on the other side that faces the one side of the insulator110. In addition, the second region of the insulator110includes a first main surface153on one side of the insulator110and a second main surface154on the other side that faces the one side of the insulator110.

The first main surface151in the first region is on the same side as the first main surface153in the second region. Similarly, the second main surface152in the first region is on the same side as the second main surface154in the second region.

The terminal electrodes211and212are provided on the first main surface151. Each of the terminal electrodes211and212is provided as an input-output electrode to connect to an external device.

The insulator110is preferably made of a polyimide type resin or LCP, for example. In addition, the insulator110may be made of a fluororesin, for example. More specifically, the fluororesin includes polytetrafluoroethylene (PTFE), perfluoroalkoxy alkane (PFA), ethylene-tetrafluoroethylene copolymer (ETFE), and perfluoroethylene-propene copolymer (FEP), for example. Accordingly, chemical resistance, heat resistance, and electrical characteristics are able to be increased. The first signal line310and the second signal line320are made of a material having high electrical conductivity, for example, copper (Cu). The terminal electrodes211and212and the connection electrodes221and222are planar conductors, and are made of copper foil, for example.

A more specific structure of the multilayer substrate10will be described. As shown inFIG.2, the insulator110is defined by stacking a first layer L1, a second layer L2, a third layer L3, and a fourth layer L4on each other.

The first layer L1and the fourth layer L4are provided only in the first region. The second layer L2and the third layer L3are provided in the first region and the second region. In other words, since the first layer L1and the fourth layer L4are not provided in the second region, the thickness of the second region is smaller than the thickness of the first region.

The third layer L3includes a first signal line310and a second signal line320. The first signal line310and the second signal line320have the same or substantially the same shape and are located at parallel or substantially parallel positions. Thus, the first signal line310and the second signal line320are coupled to each other and define a differential line (a coupled line). A detailed structure of the first signal line310and the second signal line320will be described below.

As described above, the terminal electrodes211and212are provided on the first layer L1(the first main surface151of the insulator110). The connection electrodes221and222are provided on the second layer L2.

Interlayer connection conductors TH12and TH22are provided on the first layer L1, and interlayer connection conductors TH11and TH21are provided on the second layer L2. The interlayer connection conductors TH11, TH12, TH21, and TH22are provided, for example, by filling a through hole with conductive paste and solidifying the conductive paste.

The first signal line310is connected to the connection electrode221on the second layer L2through the interlayer connection conductor TH11. The connection electrode221is connected to the terminal electrode211on the first layer L1through the interlayer connection conductor TH12. Thus, the first signal line310is connected to the terminal electrode211.

Similarly, the second signal line320is connected to the connection electrode222on the second layer L2through the interlayer connection conductor TH21. The connection electrode222is connected to the terminal electrode212on the first layer L1through the interlayer connection conductor TH22. Thus, the second signal line320is connected to the terminal electrode212.

A more specific structure of the first signal line310will be described with reference toFIG.2andFIGS.3A and3B. The first signal line310is defined by connecting the signal line311and the signal line312. The signal line311is provided in the first region, and the signal line312is provided in the second region.

The second signal line320is defined by connecting the signal line321and the signal line322. The signal line321is provided in the first region, and the signal line322is provided in the second region.

The first signal line310and the second signal line320, in the first region and the second region, are parallel or substantially parallel with an X-axis direction, and are provided on the same plane (the third layer L3).

FIG.3Ais a view of the first region as viewed in the X-axis direction, andFIG.3Bis a view of the second region as viewed in the X-axis direction. A line width W2of the signal line312(the signal line322) is smaller than a line width W1of the signal line311(the signal line321).

In addition, a distance D1between the first signal line310and the second signal line320in the first region is larger than a distance D2between the first signal line310and the second signal line320in the second region. In other words, the distance D2between the first signal line310and the second signal line320in the second region is smaller than the distance D1between the first signal line310and the second signal line320in the first region.

As a result, in the second region, the line width of the first signal line310and the line width of the second signal line320become smaller, and the distance between the first signal line310and the second signal line320becomes smaller (shorter). Thus, a coupled state between the first signal line310and the second signal line320is able to be easily maintained.

FIG.4is a side cross-sectional view showing a state in which the multilayer substrate10is bent, as viewed from the first signal line310in a Y-axis direction. The multilayer substrate10has a shape that is easily bent in the second region, and is bent in the second region that is thinner than the first region. The multilayer substrate10may be structured so that a second region end portion of the second region being a portion to be connected to the first region may not have a curvature. In other words, the multilayer substrate10may be structured to be bent in a portion of the second region. As a result, stress caused by bending is able to be further reduced or prevented from being transmitted to the first region.

As described above, the second region is thinner than the first region, and, even when the multilayer substrate10is bent in the second region, according to the features and structure described above, the characteristic change of the differential line in the state in which the multilayer substrate10is bent is significantly reduced or prevented, and desired characteristics are able to be provided.

In addition, the multilayer substrate10may preferably have, for example, the following relationship with the signal line in the first region, the signal line in the second region, and a connecting portion. The connecting portion is a portion that connects the signal line in the first region and the signal line in the second region. The connecting portion defines a direction (the Y-axis direction) perpendicular or substantially perpendicular to a transmission direction (the X-axis direction) of the signal line in the first region and the signal line in the second region, as a transmission direction of the signal.

A width Wb (a length parallel or substantially parallel with the X-axis direction) of the connecting portion is smaller than a width Wa (a length parallel or substantially parallel with the Y-axis direction) of the signal line311in the first region, and larger than a width Wc (a length parallel with the Y-axis direction) of the signal line312in the second region. In other words, the width Wa of the signal line311in the first region, the width Wb of the connecting portion, and the width Wc of the signal line312in the second region are reduced in this order. As a result, an abrupt change in impedance in the connecting portion of the first region and the second region is able to be significantly reduced or prevented, and a transmission loss is able to be reduced.

Second Preferred Embodiment

A multilayer substrate according to a second preferred embodiment of the present invention will be described with reference to the drawings.FIG.5is an exploded plan view of a multilayer substrate10A according to the second preferred embodiment of the present invention.FIG.6is a side cross-sectional view of the multilayer substrate10A according to the second preferred embodiment of the present invention. InFIG.5, wiring in a stacking direction (the Z-axis direction) is substantially the same at both ends.

As shown inFIG.5andFIG.6, the multilayer substrate10A according to the second preferred embodiment of the present invention is different from the multilayer substrate10according to the first preferred embodiment of the present invention in the shape of a first signal line310A, the shape of a second signal line320A, the structure of the first signal line310A and the second signal line320A that face each other in the Z-axis direction, the inclusion of a connection electrode231, and the shapes of a second layer L2and a fourth layer L4. Other basic features of the multilayer substrate10A are the same as or similar to the basic features of the multilayer substrate10, and a description of the same or similar features will be omitted.

The multilayer substrate10A includes an insulator110A that includes a first region and a second region, and the first layer L1and the second layer L2are provided only in the first region of the insulator110A. The third layer L3and the fourth layer L4are provided in the first region and the second region of the insulator110A. In other words, since the first layer L1and the second layer L2are not provided in the second region, the thickness of the second region is smaller than the thickness of the first region.

The first signal line310A includes a signal line311A and a signal line312A. The signal line311A is provided in the first region of the second layer L2, and the signal line312A is provided in the second region of the third layer L3.

Interlayer connection conductors TH11and TH23are provided in the first layer L1. Interlayer connection conductors TH22and TH31are provided in the second layer L2. An interlayer connection conductor TH21is provided in the third layer L3. The interlayer connection conductors TH11, TH21, TH22, TH23, and TH31are provided, for example, by filling a through hole with conductive paste and solidifying the conductive paste.

The first signal line310A is defined by connecting the signal line311A and the signal line312A by the interlayer connection conductor TH31. The first signal line310A is connected to a terminal electrode211on the first layer L1through the interlayer connection conductor TH11. Thus, the first signal line310A is connected to the terminal electrode211.

The second signal line320A is defined by connecting a signal line321A and a signal line322A. The signal line321A is provided in the first region, and the signal line322A is provided in the second region.

In addition, the second signal line320A is connected to a connection electrode231on the third layer L3through the interlayer connection conductor TH21. The connection electrode231is connected to a terminal electrode221on the second layer L2through the interlayer connection conductor TH22. The connection electrode221is connected to a terminal electrode212on the first layer L1through the interlayer connection conductor TH23. Thus, the second signal line320A is connected to the terminal electrode212.

The first signal line310A and the second signal line320A are provided at positions that are parallel or substantially parallel with the X-axis direction and face each other in the Z-axis direction. Thus, the first signal line310A and the second signal line320A define a differential line (a coupled line).

In addition, the interlayer connection conductor TH31is provided in the first signal line310A near a first main surface151on which the terminal electrodes211and212are provided. In other words, the interlayer connection conductor TH31extends in a direction (toward the second signal line320A) in which the first signal line310A near the first main surface151is spaced apart from the terminal electrode211. Thus, the line length of the signal line from one terminal electrode211to the other terminal electrode211through the first signal line310A is able to be approximated to the line length of the signal line from one terminal electrode212to the other terminal electrode212through the second signal line320A, so that deviations in impedance are able to be reduced.

In the Y-axis direction of the second region, the line width WA1of the signal line312A in the first signal line310A is preferably larger than the line width WA2of the signal line322A in the second signal line320A, for example. Thus, the first signal line310A, even when shifting in the Y-axis direction in a plan view of the multilayer substrate10A in the Z-axis direction, overlaps with the second signal line320A more easily. In other words, the influence of a positional shift at a time when the multilayer substrate10A is provided is able to be reduced.

FIG.6is a side cross-sectional view of a state in which the multilayer substrate10A is bent. The multilayer substrate10A is bent in the second region that is thinner than the first region. The first signal line310A (the signal line311A) is connected to a connector500A through the terminal electrode211. Although the illustration is omitted inFIG.6, the second signal line320A (the signal line321A) is connected to the connector500A through the terminal electrode212. In addition, the connector500A is connected to another component (the illustration is omitted).

The multilayer substrate10A is preferably bent so that the fourth layer L4may face inside, for example. Thus, the first signal line310A (the signal line312A) extends. In other words, the length of the first signal line310A is able to be further approximated to the length of the second signal line320A.

Even with the features described above, a coupled state between the first signal line310A and the second signal line320A is able to be maintained. In addition, the second region is thinner than the first region, and, even when the multilayer substrate10A is bent in the second region, the characteristic change of the differential line in the state in which the multilayer substrate10A is bent is significantly reduced or prevented, and desired characteristics are able to be provided. Moreover, a difference in the length of the first signal line310A and the second signal line320A is able to be reduced.

Furthermore, in the second region, the distance between the signal line322A and a curved inner surface of the multilayer substrate10A is smaller than the distance between the signal line312A and a curved outer surface of the multilayer substrate10A. As a result, the conductor is brought closer to a curved inner region, the second region is more easily bent.

Third Preferred Embodiment

A multilayer substrate according to a third preferred embodiment of the present invention will be described with reference to the drawings.FIG.7is an exploded plan view of a multilayer substrate10B according to the third preferred embodiment of the present invention.FIG.8is a side cross-sectional view showing a state in which the multilayer substrate10B according to the third preferred embodiment of the present invention is connected to a connector500B. InFIG.7, the wiring in the stacking direction (the Z-axis direction) is the same or substantially the same at both ends.

As shown inFIG.7andFIG.8, the multilayer substrate10B according to the third preferred embodiment is different from the multilayer substrate10A according to the second preferred embodiment in the inclusion of a fifth layer L5and a sixth layer L6, the shapes of a first signal line310B and a second signal line320B, and the inclusion of a terminal electrode211B and a terminal electrode261B. Other basic features of the multilayer substrate10B are the same as or similar to the basic features of the multilayer substrate10A, and a description of the same or similar features will be omitted. The sixth layer L6corresponds to a surface on the side of the second main surface152.

The multilayer substrate10B includes an insulator110B that includes a first region and a second region, and a first layer L1, the fifth layer L5, and the sixth layer L6are provided only in the first region of the insulator110B. In other words, the first layer L1, the fifth layer L5, and the sixth layer L6are not provided in the second region of the insulator110B. Specifically, the thickness of the second region of the multilayer substrate10B is smaller than the thickness of the first region.

The terminal electrode211B is provided on the first layer L1, and the terminal electrode261B is provided on the sixth layer L6. The surface on which the terminal electrode211B is provided corresponds to the first main surface151, and the surface on which the terminal electrode261B is provided corresponds to the second main surface152.

An interlayer connection conductor TH11is provided in the first layer L1. An interlayer connection conductor TH31is provided in the second layer L2. An interlayer connection conductor TH32is provided in the fourth layer L4. An interlayer connection conductor TH21is provided in the fifth layer L5. The interlayer connection conductors TH11, TH21, TH31, and TH32are provided, for example, by filling a through hole with conductive paste and solidifying the conductive paste.

The first signal line310B is defined by connecting the signal line311B and the signal line312B. The signal line311B is provided in the first region of the second layer L2. The signal line312B is provided in the second region of the third layer L3. The signal line311B and the signal line312B are connected by the interlayer connection conductor TH31. The line width of the signal line312B is smaller than the line width of the signal line311B.

The first signal line310B is connected to a terminal electrode211B on the first layer L1through the interlayer connection conductor TH11. Thus, the first signal line310B is connected to the terminal electrode211B.

The second signal line320B is defined by connecting a signal line321B and a signal line322B. The signal line321B is provided in the first region of the fifth layer L5. The signal line322B is provided in the second region of the fourth layer L4. The signal line321B and the signal line322B are connected by the interlayer connection conductor TH32. The line width of the signal line322B is smaller than the line width of the signal line321B.

The second signal line320B is connected to the terminal electrode261B on the sixth layer L6through the interlayer connection conductor TH21. Thus, the second signal line320B is connected to the terminal electrode261B.

The first signal line310B and the second signal line320B are provided at positions that are substantially parallel with the X-axis direction and face each other in the Z-axis direction. Thus, the first signal line310B and the second signal line320B define a differential line (a coupled line).

Accordingly, the length of the first signal line310B and the second signal line320B are able to be equal or substantially to each other. In other words, a distance from the terminal electrode211B on one end to the terminal electrode211B on another end and a distance from the terminal electrode261B on one end to the terminal electrode261B on another end are able to be equal or substantially equal to each other.

FIG.8is a side cross-sectional view of the multilayer substrate10B as viewed in the Y-axis direction, showing a structure in which the multilayer substrate10B is connected to the connector500B. The connector500B includes a connector housing501, a wiring conductor502, a connection conductor503, contact terminals504and505, and an external connection opening506. The connection terminals504and505are connected to the wiring conductor502through the connection conductor503. The wiring conductor502is exposed outside when the connector housing501includes the external connection opening506. The exposed portion is provided as an input-output electrode to connect to an external device.

In the Z-axis direction of the multilayer substrate10B, the connector500B is structured to include at least a portion of a first main surface151and at least a portion of a second main surface152. The multilayer substrate10B connects the connection terminal504and the terminal electrode211B, and connects the connection terminal505and the terminal electrode261B. Then, as described above, the external connection opening506is provided as an input-output electrode, and the multilayer substrate10B is able to be connected to an external device.

Even with the features described above, a coupled state between the first signal line310B and the second signal line320B is able to be maintained, and the characteristic change is able to be further reduced or prevented.

In addition, in multilayer substrate10B, the first layer L1to the third layer L3and the fourth layer L4to the sixth layer L6have a line symmetric structure. Moreover, with the connector500B including the features described above, the distance between the connection terminal504and the terminal electrode211B is equal or substantially equal to the distance between the connection terminal505and the terminal electrode261B. As a result, in the structure of the connector500B and the multilayer substrate10B, a transmission loss is able to be reduced.

In addition, similarly to the above-described preferred embodiments, the second region is thinner than the first region, so that the multilayer substrate10B easily bends (is easily bent) in the second region, the characteristic change of the differential line in the state in which the multilayer substrate10B is bent is significantly reduced or prevented, and desired characteristics are able to be provided.

Fourth Preferred Embodiment

A multilayer substrate according to a fourth preferred embodiment of the present invention will be described with reference to the drawings.FIG.9is an exploded plan view of a multilayer substrate10C according to the fourth preferred embodiment of the present invention.FIG.10Ais an external perspective view of the multilayer substrate10C according to the fourth preferred embodiment of the present invention, andFIGS.10B and10Care side cross-sectional views of the multilayer substrate10C according to the fourth preferred embodiment of the present invention. InFIG.9, the wiring in a stacking direction (the Z-axis direction) is the same or substantially the same at both ends.

As shown inFIG.9, andFIGS.10A to10C, the multilayer substrate10C according to the fourth preferred embodiment is different from the multilayer substrate10A according to the second preferred embodiment in the inclusion of a fifth layer L5and a sixth layer L6, the shapes of a first signal line310C and a second signal line320C, and the inclusion of terminal electrodes211and212, connection electrodes221,222,231,232,233, and251, and conductor patterns241and242. Other basic features of the multilayer substrate10C are the same as or similar to the basic features of the multilayer substrate10A, and a description of the same or similar features will be omitted.

In the multilayer substrate10C, the first layer L1and the sixth layer L6are provided only in a first region. In other words, since the first layer L1and the sixth layer L6are not provided in the second region, the thickness of the second region is smaller than the thickness of the first region.

The terminal electrodes211and212are provided on the first layer L1. The connection electrodes221and222are provided on the second layer L2. The connection electrodes231,232, and233are provided on the third layer L3. The conductor patterns241and242are provided on the fourth layer L4. The connection electrode251is provided on the fifth layer L5. The surface on which the terminal electrodes211and212are provided corresponds to the first main surface151.

As shown inFIG.9, an interlayer connection conductor TH31is provided in the second layer L2. An interlayer connection conductor TH32is provided in the fifth layer L5. The interlayer connection conductors TH31and TH32are provided, for example, by filling a through hole with conductive paste and solidifying the conductive paste.

The first signal line310C is defined by connecting the signal line311C and the signal line312C. The signal line311C is provided in the first region of the second layer L2, and the signal line312C is provided in the second region of the third layer L3. The signal line311C and the signal line312C are connected by the interlayer connection conductor TH31. The line width of the signal line312C is smaller than the line width of the signal line311C.

The second signal line320C is defined by connecting a signal line321C and a signal line322C. The signal line321C is provided in the first region of the sixth layer L6, and the signal line322C is provided in the second region of the fifth layer L5. The signal line321C and the signal line322C are connected by the interlayer connection conductor TH32. The line width of the signal line322C is smaller than the line width of the signal line321C.

The first signal line310C and the second signal line320C are provided at positions that are parallel or substantially parallel with the X-axis direction and face each other in the Z-axis direction. Thus, the first signal line310C and the second signal line320C define a differential line (a coupled line).

A structure in which the first signal line310C is connected to a connector500C will be described with reference toFIG.9andFIGS.10A and10B. The first signal line310C is connected to the connector500C through the terminal electrode211.

The connector500C shown inFIGS.10A to100is connected to the terminal electrodes211and212on a first main surface151of an insulator110C.

Interlayer connection conductors TH15and TH25are provided in the first layer L1. Interlayer connection conductors TH11, TH14, and TH24are provided in the second layer L2. Interlayer connection conductors TH12, TH13, and TH23are provided in the third layer L3. An interlayer connection conductor TH22is provided in the fourth layer L4. An interlayer connection conductor TH21is provided in the fifth layer L5. The interlayer connection conductors TH11, TH12, TH13, TH14, TH15, TH21, TH22, TH23, TH24, and TH25are provided, for example, by filling a through hole with conductive paste and solidifying the conductive paste.

A connection structure of the first signal line310C will be described. The signal line311C on the second layer L2is connected to the connection electrode233on the third layer L3through the interlayer connection conductor TH11. In the third layer L3, the connection electrode233is connected to the conductor pattern241on the fourth layer L4through the interlayer connection conductor TH12. The conductor pattern241is connected to the connection electrode231on the third layer L3through the interlayer connection conductor TH13. The connection electrode231is connected to the connection electrode221on the second layer L2through the interlayer connection conductor TH14. The connection electrode221is connected to the terminal electrode211on the first layer L1through the interlayer connection conductor TH15. Accordingly, the first signal line310C is connected to the terminal electrode211on the first layer L1.

Similarly, a structure in which the second signal line320C is connected to the connector500C will be described with reference toFIG.9andFIGS.10A and100. The second signal line320C is connected to the connector500C through the terminal electrode212.

A connection structure of the second signal line320C will be described. The signal line321C on the sixth layer L6is connected to the connection electrode251on the fifth layer L5through the interlayer connection conductor TH21. The connection electrode251is connected to the conductor pattern242on the fourth layer L4through the interlayer connection conductor TH22. The conductor pattern242is connected to the connection electrode232on the third layer L3through the interlayer connection conductor TH23. The connection electrode232is connected to the connection electrode222on the second layer L2through the interlayer connection conductor TH24. The connection electrode222is connected to the terminal electrode212on the first layer L1through the interlayer connection conductor TH25. Accordingly, the second signal line320C is connected to the terminal electrode212on the first layer L1.

The distance from the first signal line310C to the terminal electrode211is compared with the distance from the second signal line320C to the terminal electrode212.

In the first signal line310C shown inFIG.9and FIG.10B, a thickness H2(a length in a thickness direction) is equal or substantially equal to a length of the interlayer connection conductor TH11+a length of the interlayer connection conductor TH12, and a thickness H1is equal or substantially equal to a length of the interlayer connection conductor TH13+a length of the interlayer connection conductor TH14+a length of interlayer connection conductor TH15.

In the second signal line320C shown inFIG.9andFIG.10C, a thickness H3(a length in the thickness direction) is equal or substantially equal to a length of the interlayer connection conductor TH21+a length of the interlayer connection conductor TH22, and a thickness H1is equal or substantially equal to a length of the interlayer connection conductor TH23+a length of the interlayer connection conductor TH24+a length of interlayer connection conductor TH25.

In other words, the distance from the first signal line310C to the terminal electrode211is equal or substantially equal to H1+H2+a length of the conductor pattern241. In addition, the distance from the second signal line320C to the terminal electrode212is equal or substantially equal to H1+H3+a length of the conductor pattern242. The length of the conductor pattern241and the length of the conductor pattern242are equal or substantially equal to each other.

The second layer L2, the third layer L3, the fourth layer L4, and the fifth layer L5that define the insulator110C have the same or substantially the same thickness in the Z-axis direction, H2=H3is satisfied. Therefore, the distance from the first signal line310C to the terminal electrode211is equal or substantially equal to the distance from the second signal line320C to the terminal electrode212.

In other words, the connection structure of the first signal line310C corresponds to a structure including a wiring portion that passes (bypasses) the interlayer connection conductors TH11and TH12. In other words, the structure does not provide a conductor at a minimum distance, but includes a portion to purposely increase the length of the conductor. The distance of the interlayer connection conductors TH21and TH22of the second signal line320C is offset by such a wiring portion. Thus, the distance from the first signal line310C to the terminal electrode211is able to be equal or substantially to the distance from the second signal line320C to the terminal electrode212.

Even with the features described above, the second region is thinner than the first region, so that the multilayer substrate10C easily bends (is easily bent) in the second region, the characteristic change of the differential line in the state in which the multilayer substrate10C is bent is significantly reduced or prevented, and desired characteristics are able to be provided. Further, the distance from the first signal line310C to the terminal electrode211and the distance from the second signal line320C to the terminal electrode212are equal or substantially equal to each other, so that the difference between the two line lengths is reduced and a transmission loss of the multilayer substrate10C is able to be reduced.

In addition, a coupled state between the first signal line310C and the second signal line320C is able to be maintained, and the characteristic change is able to be further reduced or prevented.

Fifth Preferred Embodiment

A multilayer substrate according to a fifth preferred embodiment of the present invention will be described with reference to the drawings.FIG.11is a side cross-sectional view of a multilayer substrate10D according to the fifth preferred embodiment of the present invention.

As shown inFIG.11, the multilayer substrate10D according to the fifth preferred embodiment is different from the multilayer substrate10A according to the second preferred embodiment in the inclusion of ground conductors601and602, and the line widths and positions of a first signal line310D and a second signal line320D. Other basic features of the multilayer substrate10D are the same as or similar to the basic features of the multilayer substrate10, and a description of the same or similar features will be omitted.

In the Y-axis direction of the multilayer substrate10D, a line width WD1of the first signal line310D is smaller than a line width WD2of the second signal line320D. Thus, the first signal line310D, even in a case of shifting in the Y-axis direction when the multilayer substrate10D is viewed in the Z-axis direction, overlaps with the second signal line320D. In other words, the influence of a positional shift at a time when the multilayer substrate10D is provided is able to be reduced.

The ground conductor601is provided on a first main surface151of the multilayer substrate10D. The ground conductor602is provided on a second main surface152of the multilayer substrate10D. More specifically, the line widths of the ground conductor601and the ground conductor602are larger than the line widths of the first signal line310D and the second signal line320D in the Y-axis direction. Thus, noise that is generated from the first signal line310D and the second signal line320D is able to be reduced or prevented from being emitted to the outside of the multilayer substrate10D. The ground conductor601corresponds to a “first ground conductor”, and the ground conductor602corresponds to a “second ground conductor”.

In addition, in the Z-axis direction of the multilayer substrate10D, the first signal line310D is spaced apart from the first main surface151by a distance HD1. In other words, the first signal line310D is spaced apart from the ground conductor601by the distance HD1.

Similarly, the second signal line320D is spaced apart from the second main surface152by a distance HD2. In other words, the second signal line320D is spaced apart from the ground conductor602by the distance HD2.

As described above, the line width WD1of the first signal line310D is provided to be smaller than the line width WD2of the second signal line320D. Accordingly, the first signal line310D and the second signal line320D may satisfy the relationship of distance HD1<distance HD2. As a result, the effect of making the impedance of the first signal line310D and the second signal line320D the same or substantially the same is provided.

The above-described preferred embodiments describe a structure in which the ground conductor601is provided on the first main surface151and the ground conductor602is provided on the second main surface152. However, as long as at least one of the ground conductors is provided, the noise that is generated from the first signal line310D and the second signal line320D is able to be reduced or prevented from being emitted to the outside of the multilayer substrate10D. However, for example, the ground conductors may be preferably provided on both sides of the first main surface151and the second main surface152to increase the effect of reducing noise that is emitted to the outside of the multilayer substrate10D.

Even with the features described above, a coupled state between the first signal line310D and the second signal line320D is able to be maintained. In addition, the second region is thinner than the first region, so that the multilayer substrate10D easily bends (is easily bent) in the second region, the characteristic change of the differential line in the state in which the multilayer substrate10D is bent is significantly reduced or prevented, and desired characteristics are able to be provided.

By including a layer (the second layer L2in the multilayer substrate10of the first preferred embodiment, for example) on which the first signal line and the second signal line are not provided in the second region, the second region is omissible. As a result, the second region is able to be further thinned, and thus the multilayer substrate10D is able to be more easily bent.

In addition, with respect to the fifth preferred embodiment, a structure in which the widths of the first signal line and the second signal line are equal or substantially equal to each other and the first signal line and the second signal line are provided in parallel or substantially in parallel with each other in the Y-axis direction and provided between two ground conductors is able to be used. Accordingly, the advantageous operational effect by including the ground conductor, that is, the advantageous effect of reducing the noise that is emitted to the outside, is able to be increased.

In addition, with respect to the fifth preferred embodiment, a structure in which the two ground conductors are omitted is able to be used. In this structure, the advantageous operational effect by the first signal line and the second signal line that are provided along in the Z-axis direction (the thickness direction of the insulator) and have different widths, that is, influence of a positional shift when a multilayer substrate is provided, is able to be reduced.

The above-described preferred embodiments describe a structure in which the connecting portion that connects the signal line in the first region and the signal line in the second region has a shape to define a direction perpendicular or substantially perpendicular to a transmission direction of the signal line in the first region and the signal line in the second region as a signal transmission direction. However, the connecting portion may have a shape shown inFIG.12.

FIG.12is an enlarged plan view showing another connecting portion that connects a signal line in the first region and a signal line in the second region. The multilayer substrate shown inFIG.12is different from the multilayer substrate10according to the first preferred embodiment in the shape of the connecting portion that connects the signal line in the first region and the signal line in the second region. Other basic features of the multilayer substrate shown inFIG.12are the same as or similar to the basic features of the multilayer substrate10, and a description of the same or similar features will be omitted.

In the multilayer substrate shown inFIG.12, the signal line311in the first region and the signal line312in the second region are connected by a connecting portion391. In addition, the signal line321in the first region and the signal line322in the second region are connected by a connecting portion392.

The connecting portion391has the same or substantially the same width as the signal line311at a connection end to the signal line311, and has the same or substantially the same width as the signal line312at a connection end to the signal line312. The width of the signal line311is larger than the width of the signal line312. The connecting portion391has a shape in which the width is gradually tapered from the connection end to the signal line311toward the connection end to the signal line312.

The connecting portion392has the same or substantially the same width as the signal line321at a connection end to the signal line321, and has the same or substantially the same width as the signal line322at a connection end to the signal line322. The width of the signal line321is larger than the width of the signal line322. The connecting portion392has a shape in which the width is gradually tapered from the connection end to the signal line321toward the connection end to the signal line322.

According to the features described above, a drastic change in impedance in the connecting portion391and the connecting portion392is able to be further reduced or prevented, so that a transmission loss is able to be further reduced. In addition, connection between the connection portion391and the signal line311, connection between the connection portion391and the signal line312, connection between the connection portion392and the signal line321, and connection between the connection portion392and the signal line322have no corner portion in the conductor pattern. Accordingly, unnecessary concentration of an electric field or the like on the corner portion does not occur, and a transmission loss is able to be reduced.

While preferred embodiments of the present invention have been described above, it is to be understood that variations and modifications will be apparent to those skilled in the art without departing from the scope and spirit of the present invention. The scope of the present invention, therefore, is to be determined solely by the following claims.