Circuit board module

A circuit board module is electrically connectable to a socket by inserting one end part thereof into the socket, and includes a circuit board and a terminal board having a first surface provided with a column of socket-connection pads and mounted on the surface of the circuit board at the one end part. The terminal board includes first, second, and third pad columns provided on a second surface of the terminal board opposite to the first surface. The circuit board includes fourth, fifth, and sixth pad columns respectively provided on the surface of the circuit board opposing the second surface of the terminal board, at positions opposing the first, second, and third pad columns of the terminal board, respectively.

CROSS-REFERENCE TO RELATED APPLICATION

This application is based upon and claims the benefit of priority of the prior Japanese Patent Application No. 2017-090052, filed on Apr. 28, 2017, the entire contents of which are incorporated herein by reference.

FIELD

Certain aspects of the embodiments discussed herein are related to circuit board modules.

BACKGROUND

A conventional circuit board module, including a terminal board, is inserted into and extracted from a socket when required. For example, the terminal board is fixed to one end part of a circuit board by solder. Electronic components are mounted on a surface of the circuit board. The terminal board has a first surface opposing the surface of the circuit board, and a second surface on a side opposite from the first surface. Socket-connection pads for making contact with and electrically connecting to terminals of the socket are provided on the second surface of the terminal board. In addition, pads, having the same size as the socket-connection pads, are provided on the first surface of the terminal board. The pads provided on the first surface of the terminal board are connected to pads provided on the surface of the circuit board by solder. For example, Japanese Laid-Open Patent Publication No. 2003-046273 proposes a circuit board module similar to that described above.

In the circuit board module, the terminal board is required to connect to the circuit board with a high positional accuracy and a high degree of parallelism, in order to improve reliability of the connection between the circuit board module and the socket. However, in the conventional circuit board module, the positional accuracy and the degree of parallelism of the terminal board with respect to the circuit board may not always be satisfactory.

SUMMARY

Accordingly, it is an object in one aspect of the embodiments to provide a circuit board module which can improve positional accuracy and degree of parallelism of a terminal board with respect to a circuit board.

According to one aspect of the embodiments, a circuit board module that is electrically connectable to a socket by inserting one end part thereof into the socket, and extractable from the socket, includes a circuit board having a surface mounted with an electronic component, and a terminal board having a first surface provided with a column of socket-connection pads, and mounted on the surface of the circuit board at the one end part, wherein the terminal board includes a first pad column, a second pad column, and a third pad column respectively provided on a second surface of the terminal board opposite to the first surface, wherein the first pad column includes a plurality of first pads arranged at predetermined intervals in a first direction, the second pad column includes a plurality of second pads, equal to a number of first pads, arranged at the predetermined intervals in the first direction, and the third pad column includes a plurality of third pads, equal to the number of first pads, arranged at the predetermined intervals in the first direction, wherein the second pad column and the third pad column are arranged on both sides of the first pad column along a second direction perpendicular to the first direction, separated from the first pad column, to be line symmetrical to a centerline of the first pad column that is parallel to the first direction, wherein each first pad has an area larger than an area of each second pad and an area of each third pad, wherein, among adjacent first, second, and third pads along the second direction, centerlines of the second pad and the third pad along the second direction match a centerline of the first pad along the second direction, wherein the circuit board includes a fourth pad column of fourth pads, a fifth pad column of fifth pads, and a sixth pad column of sixth pads respectively provided on a surface of the circuit board opposing the second surface of the terminal board, at positions opposing the first pad column, the second pad column, and the third pad column of the terminal board, respectively, and wherein mutually opposing pads of the first pad column and the fourth pad column, the second pad column and the fifth pad column, and the third pad column and the sixth pad column are respectively bonded by a bonding material.

DESCRIPTION OF EMBODIMENTS

Preferred embodiments of the present invention will be described with reference to the accompanying drawings. In the drawings, those parts that are the same are designated by the same reference numerals, and a repeated description of the same parts may be omitted.

A circuit board module in each embodiment according to the present invention will be described.

First Embodiment

FIGS. 1A and 1Bare diagrams illustrating an example of the circuit board module in a first embodiment.FIG. 1Aillustrates a plan view of the circuit board module, andFIG. 1Billustrates a cross sectional view of the circuit board module along a line A-A inFIG. 1A.FIGS. 2A and 2Bare perspective views illustrating the example of the circuit board module in the first embodiment.FIG. 2Aillustrates the circuit board module by itself, andFIG. 2Billustrates the circuit board module in a state in which the circuit board module is inserted into a socket. InFIG. 2B, a socket90is not a constituent element of a circuit board module1.

As illustrated inFIGS. 1A, 1B, 2A, and 2B, the circuit board module1includes a circuit board10, and a terminal board20. One end part of the circuit board module1can be inserted into and extracted from the socket90. The circuit board module1is electrically connected to the socket90when one end part of the circuit board module1is inserted into the socket90. In other words, the circuit board module1is electrically connectable to the socket90by inserting one end part thereof into the socket90, and the circuit board module1is extractable from the socket90.

The socket90is made to conform to a predetermined format or standard, and may be a slot into which a memory card is inserted. The circuit board module1has shape and dimensions matching the format or standard of the socket90. Of course, the socket90is not limited to the memory card insertion slot, and may be formed to have arbitrary shape and dimensions. In addition, the circuit board module1may be famed to have shape and dimensions that enable the circuit board module1to be inserted into and extracted from the socket90.

The circuit board10includes a board (or base)11, board-connection pads12, component-connection pads13, one or more active components14, and one or more passive components15. In the following description, the active components14and the passive components15may be collectively referred to as “electronic components”. For the sake of convenience, the active components14, the passive components15, and a board (or base)21of the terminal board20illustrated inFIG. 1Aare indicated by half-tone patterns.

For example, the board11may be formed by a plate-shaped member or the like including a glass cloth impregnated with a thermosetting insulating resin such as an, epoxy resin or the like. In this example, the board11has an approximately rectangular shape in a plan view of the board11. The plan view of the board11or circuit board10is a view of the board11or circuit board10from above a surface11mof the board11inFIG. 1A, viewed in a direction perpendicular to the surface11mof the board11inFIG. 1B.

The board-connection pads12are used to electrically connect the circuit board10to the terminal board20. The board-connection pads12may be provided on the surface11mof the board11of the circuit board10, at one end part (right end part inFIG. 1B) of the board11corresponding to the one end part of the circuit board module1. The component-connection pads13are used to mount the active components14and the passive components15on the circuit board10. The component-connection pads13may be provided at arbitrary positions on the surface11mof the board11of the circuit board10. Selected board-connection pads12may be electrically connected to selected component-connection pads13via wiring patterns (not illustrated). The illustration of the wiring patterns is omitted inFIGS. 1A and 1Bto simplify these figures, however, the wiring patterns may be provided on the surface11mof the board11of the circuit board10, and may also be provided on a surface11nof the board11of the circuit board10on a side opposite from the surface11m,when required. The board-connection pads12and the component-connection pads13may be made of a material such as copper or the like, for example. Surfaces of the copper or the like forming the board-connection pads12and the component-connection pads13may be plated with a material such as gold or the like, by electroless plating, for example. Details of the board-connection pads12will be described later in the specification.

The active components14and the passive components15are mounted on the surface11mof the board11of the circuit board10via a bonding material30provided on the component-connection pads13. The active components14may include integrated circuits, transistors, diodes, or the like, for example, and the required active components14may be mounted on the circuit board10. On the other hand, the passive components15may include resistors, capacitors, inductors, or the like, for example, and the required passive components15may be mounted on the circuit board10. The bonding material30may be solder or the like, for example. The solder may be formed by materials such as an alloy including Pb, an alloy of Sn and Cu, an alloy of Sn and Sb, an alloy of Sn and Ag, an alloy of Sn, Ag, and Cu, or the like, for example. The active components14and the passive components15may be provided on the surface11nof the board11of the circuit board10, when required. In this case, the wiring patterns may also be provided on the surface11nof the board11of the circuit board10.

The terminal board20includes the board21, socket-connection pads22, board-connection pads23, and via wirings24. The terminal board20is provided at one end part (right end part inFIGS. 1A and 1B) of the board11of the circuit board10, corresponding to the one end part of the circuit board module1. The board-connection pads23of the terminal board20are connected to the board-connection pads12of the circuit board10via the bonding material30.

For example, the board21may be formed by a plate-shaped member or the like including a glass cloth impregnated with a thermosetting insulating resin such as an epoxy resin or the like. In this example, the board21has an approximately rectangular shape in a plan view of the board21. The plan view of the board21is a view of the board21from above a surface21mof the board21of the terminal board20inFIG. 1A, viewed in a direction perpendicular to the surface21mof the board21in FIG.1B.

The socket-connection pads22are provided on the surface21mof the board21of the terminal board20, and make contact with and electrically connect to terminals (not illustrated) within the socket90. The socket-connection pads22may have an approximately rectangular shape that is elongated in an X-axis direction inFIG. 1A, for example. A centerline22rof the socket-connection pad22, indicated by a one-dot chain line inFIG. 1A, is parallel to the X-axis direction. A plurality of socket-connection pads22are arranged at predetermined intervals in a Y-axis direction inFIG. 1A, for example. In each of the embodiments, the X-axis direction, Y-axis direction, and Z-axis direction are perpendicular to each other as in the case of XYZ coordinate systems. In this example, 8 socket-connection pads22are arranged in the Y-axis direction, to form a column22L of socket-connection pads22. The number of socket-connection pads22that are provided, and shapes of the socket-connection pads22may be appropriately determined according to required specifications. The size or dimensions of the socket-connection pads22may also be appropriately determined according to required specifications.

The board-connection pads23are used to electrically connect the terminal board20to the circuit board10. The board-connection pads23may be provided on the surface21nof the board21of the terminal board20. The socket-connection pads22and the board-connection pads23may be made of a material such as copper or the like, for example. Durability is required of the socket-connection pads22because the circuit board module1is frequently inserted into and frequently extracted from the socket90in a repeated manner, for example. For this reason, surfaces of the copper or the like forming the socket-connection pads22are preferably plated with a material such as hard gold or the like, by electroless plating, for example. The hard gold plating improves hardness, abrasive resistance, or the like by including eutectic cobalt, eutectic nickel, or the like in the plated gold. Surfaces of the copper or the like forming the board-connection pads23may be plated with a material such as gold by electroless plating. Details of the board-connection pads23will be described later in the specification.

Selected socket-connection pads22and selected board-connection pads23may be electrically connected via the via wirings24penetrating the board21. The socket-connection pads22are electrically connected to at least one of pads231,232, and233forming the board-connection pads23. The socket-connection pads22may be electrically connected to two of the pads231,232, and233, or may be electrically connected to each of the pads231,232, and233. The pads231,232, and233forming the board-connection pads23will be described later in the specification.

According to the circuit board module1, the one end part of the board11of the circuit board10, where the terminal board20is mounted, is inserted into and extracted from the socket90. Accordingly, the terminal board20is required to connect to the circuit board10with a high positional accuracy and a high degree of parallelism. For this reason, measures are taken in the board-connection pads12of the terminal board20and in the board-connection pads23of the terminal board20.

FIGS. 3A and 3Bare diagrams illustrating an example of the board-connection pads of the circuit board module in the first embodiment.FIG. 3Aillustrates a view of the terminal board20in its entirety viewed from one side opposing the circuit board10, andFIG. 3Billustrates a view of the terminal board20viewed from another side, that is, from above the surface11mof the board11of the circuit board10.

As illustrated inFIG. 3A, the board-connection pads23provided on the surface21nof the board21of the terminal board20, include the pads231,232, and233. The pads231are arranged on the surface21nof the board21of the terminal board20, approximately at a center along the X-axis direction. The pads232and the pads233are arranged on the surface21nof the board21of the terminal board20, on both sides of the pads231along the X-axis direction. The adjacent pads231,232, and233along the X-axis direction are arranged at predetermined intervals, and a gap of approximately 1 mm, for example, is provided between 2 mutually adjacent pads231and232, and between 2 mutually adjacent pads231and233.

Among the adjacent pads231,232, and233along the X-axis direction, a centerline23rof the pad231, indicated by a one-dot chain line inFIG. 3A, is parallel to the X-axis direction. In addition, centerlines of the pads232and233are parallel to the X-axis direction, and match the centerline23rof the pad231. For example, the centerline23rapproximately matches and overlaps the centerline22rof the corresponding socket-connection pad22in the plan view illustrated inFIG. 1A.

The pads232and the pads233may have approximately rectangular shapes with approximately same areas or sizes. On the other hand, the pads231may have an approximately rectangular shape, with an area or size larger than the area or size of each of the pads232and233. A ratio of the area of the pad231to the area of each of the pads232and233may be approximately 1:0.5 to approximately 1:0.8, for example. A total area of the 3 adjacent pads231,232, and233is designed to be larger than the area of the socket-connection pad22. A ratio of the total area of the 3 adjacent pads231,232, and233to the area of the socket-connection pad22may be approximately 1.05:1 to approximately 2.0:1, for example.

A plurality of pads231are arranged at predetermined intervals in the Y-axis direction inFIG. 3A, for example. In this example, 8 pads231are arranged in the Y-axis direction, to form a pad column231L. A plurality of pads232are arranged at predetermined intervals in the Y-axis direction inFIG. 3A. In this example, the number of pads232is the same as the number of pads231, and 8 pads232are arranged in the Y-axis direction, to form a pad column232L. A plurality of pads233are arranged at predetermined intervals in the Y-axis direction inFIG. 3A. In this example, the number of pads233is the same as the number of pads231, and 8 pads233are arranged in the Y-axis direction, to form a pad column233L. A centerline23sof the pad column231L, indicated by a one-dot chain line inFIG. 3A, is parallel to the Y-axis direction. The pad column232L and the pad column233L are arranged on both sides of the pad column231L along the X-axis direction, separated from the pad column231L, to be line symmetrical to the centerline23sthat is parallel to the Y-axis direction. A gap is formed between the pad columns231L and232L, and a gap is formed between the pad columns231L and233L.

As illustrated inFIG. 3B, the board-connection pads12provided on the surface11mof the board11of the circuit board10, include pads121,122, and123. The pads121are arranged on the surface11mof the board11, at the one end part of the board11of the circuit board10. The pads122and the pads123are arranged on the surface11mof the board11of the circuit board10, on both sides of the pads121along the X-axis direction. The adjacent pads121,122, and123along the X-axis direction are arranged at predetermined intervals, and a gap of approximately 1 mm, for example, is provided between 2 mutually adjacent pads121and122, and between 2 mutually adjacent pads121and123.

A plurality of pads121are arranged at predetermined intervals in the Y-axis direction inFIG. 3B, for example. In this example, 8 pads121are arranged in the Y-axis direction, to form a pad column121L. A plurality of pads122are arranged at predetermined intervals in the Y-axis direction inFIG. 3B. In this example, the number of pads122is the same as the number of pads121, and 8 pads122are arranged in the Y-axis direction, to form a pad column122L. A plurality of pads123are arranged at predetermined intervals in the Y-axis direction inFIG. 3B. In this example, the number of pads123is the same as the number of pads121, and 8 pads123are arranged in the Y-axis direction, to form a pad column123L.

A relationship of the area of the pad121to the areas of the pads122and123, and a symmetry of the pads121,122, and123with respect to a centerline parallel to the X-axis direction, may be the same as the relationship of the area of the pad231to the areas of the pads232and233, and the symmetry of the pads232and233with respect to the centerline23r,respectively. In addition, a line symmetry of the pad columns122L and123L with respect to a centerline of the pad column121L, parallel to the Y-axis direction, may be the same as the line symmetry of the pad columns232L and233L with respect to the centerline23sof the pad column231L.

In other words, the pads121,122, and123are provided on the surface11mof the board11of the circuit board10, at positions to oppose the pads231,232, and233provided on the surface21nof the board21of the terminal board20, respectively. The pads121,122, and123are bonded to the corresponding pads231,232, and233via the bonding material30, respectively.

Accordingly, in the circuit board module1, the board-connection pads12form 3 pad columns121L,122L, and123L that are line symmetrical to the centerline of the pad column121L, parallel to the Y-axis direction. In addition, the area of each pad121forming the center pad. column121L is made larger than the area of each of the pads122and123respectively forming the pad columns122L and123L arranged on both sides of the center pad column121L. Similarly, the board-connection pads23form 3 pad columns231L,232L, and233L that are line symmetrical to the centerline23sof the pad column231L, parallel to the Y-axis direction. In addition, the area of each pad231forming the center pad column231L is made larger than the area of each of the pads232and233respectively forming the pad columns232L and233L arranged on both sides of the center pad column231L.

As a result, self-alignment function improves when bonding the center pad column121L and the center pad column231L by the bonding material30, to improve the positioning accuracy of the terminal board20with respect to the circuit board10.

In addition, the total area of the 3 adjacent pads231,232, and233is designed to be larger than the area of the socket-connection pad22, to increase pad areas that are bonded when bonding the circuit board10and the terminal board20together using the bonding material30. For this reason, it is possible to improve bonding strength of the terminal board20with respect to the circuit board10, and to reduce warping of the terminal board20.

Further, the pad columns122L and123L are arranged at line symmetrical positions with respect to the centerline of the pad column121L, parallel to the Y-axis direction. Similarly, the pad columns232L and233L are arranged at line symmetrical positions with respect to the centerline23sof the pad column231L, parallel to the Y-axis direction. Hence, it is possible to improve the degree of parallelism of the terminal board20with respect to the circuit board10.

Modification of First Embodiment

In a modification of the first embodiment, the circuit board module has an external shape different from that of the first embodiment. In the modification of the first embodiment, those parts that are the same as those corresponding parts of the first embodiment are designated by the same reference numerals, and a repeated description of the same parts may be omitted.

FIGS. 4A and 4Bare diagrams illustrating an example of the circuit board module in the modification of the first embodiment.FIG. 4Aillustrates a plan view of the circuit board, andFIG. 4Billustrates a cross sectional view of the circuit board along a line A-A inFIG. 4A.FIGS. 5A and 5Bare perspective views illustrating the example of the circuit board module in the modification of the first embodiment.FIG. 5Aillustrates the circuit board module by itself, and FIG.5B illustrates the circuit board module in a state in which the circuit board module is inserted into the socket. InFIG. 5B, a socket90is not a constituent element of a circuit board module1A.

As illustrated inFIGS. 4A, 4B, 5A, and 5B, the circuit board module1A includes a circuit board10A, and a terminal board20A. The circuit board10A differs from the circuit board10illustrated inFIGS. 1A and 1B, in that the circuit board10A uses a board11A in place of the board11. In addition, the terminal board20A differs from the terminal board20illustrated inFIGS. 1A and 1B, in that the terminal board20A uses a board21A in place of the board21.

An oblique cutout11xillustrated inFIG. 5Ais provided at each of 2 corners of the board11A at the one end part of the board11A that is inserted into and extracted from the socket90. The oblique cutout11xis an obliquely cut or chamfered portion of the board11A. The oblique cutout11xmay be replaced by a rounded corner part of the board11A. On the other hand, an oblique cutout21xillustrated inFIGS. 4A and 5Ais provided at each of 2 corners of the board21A at the one end part of the board11A that is inserted into and extracted from the socket90. The oblique cutout21xis an obliquely cut or chamfered portion of the board21A. The oblique cutout21xmay be replaced by a rounded corner part of the board21A. Otherwise, the circuit board module1A illustrated inFIGS. 4A, 4B, 5A, and 5Bis the same as the circuit board module1of the first embodiment illustrated inFIGS. 1A, 1B, 2A, and 2B.

According to the circuit board module1A, the oblique cutouts11xare provided at the 2 corners of the board11A, and the oblique cutouts21xare provided at the 2 corners of the board21A, at the one end part of the board11A that is inserted into and extracted from the socket90. For this reason, it is possible to reduce damage to the terminal board20A that may occur when the circuit board module1A is frequently inserted into and frequently extracted from the socket90in a repeated manner, for example. Otherwise, effects obtainable by the modification of the first embodiment are the same as those obtainable by the first embodiment.

Second Embodiment

In a second embodiment, the circuit board module has an external shape different from that of the first embodiment. In the second embodiment, those parts that are the same as those corresponding parts of the first embodiment are designated by the same reference numerals, and a repeated description of the same parts may be omitted.

FIGS. 6A and 6Bare diagrams illustrating an example of the circuit board module in the second embodiment.FIG. 6Aillustrates a plan view of the circuit board module, andFIG. 6Billustrates a cross sectional view of the circuit board module along a line B-B inFIG. 6A.FIG. 7is a perspective view illustrating the example of the circuit board module in the second embodiment.

As illustrated inFIGS. 6A, 6B, and 7, a circuit board module1B includes a circuit board10B, and a terminal board20B. The circuit board10B differs from the circuit board10illustrated inFIGS. 1A and 1B, in that the circuit board10B uses a board11B in place of the board11. In addition, the terminal board20B differs from the terminal board20illustrated inFIGS. 1A and 1B, in that the terminal board20B uses a board21B in place of the board21.

The board11B of the circuit board10B includes a projecting region10tthat projects towards the socket90into which the circuit board module1B is inserted, in the plan view illustrated inFIG. 6A. The terminal board21B is mounted on the projecting region10t.In addition, the board21B has an approximately rectangular shape in the plan view of the board21B illustrated inFIG. 6A, similarly to the board21illustrated inFIG. 1A.

The board-connection pads12are provided in the projecting region10tof the board11B. The board-connection pads12are electrically connected to the board-connection pads23provided on the surface21nof the board21B, via the bonding material30.

An outer periphery of the circuit board10B at the one end part of the circuit board module1B opposes an inner wall of the socket90when the circuit board module1B is inserted into the socket90. An outer periphery of the terminal board20B at the one end part of the circuit board module1B opposes the inner wall of the socket90when the circuit board module1B is inserted into the socket90. The outer periphery of the terminal board20B projects more towards the outside in an inserting direction of the circuit board module1B, that is, towards the right side inFIG. 6B, than the outer periphery of the circuit board10B, at the one end part of the circuit board module1B. A front end surface of the board21B along the inserting direction at the one end part of the circuit board module1B projects by a distance L1from a front end surface of the board11B, as illustrated inFIG. 6B. In addition, a left end surface of the board21B projects more towards the left side along the inserting direction, that is, towards a top side inFIG. 6A, than a left end surface of the board11B. A right end surface of the board21B projects more towards the right side along the inserting direction, that is, towards a bottom side inFIG. 6A, than a right end surface of the board11B. The left end surface of the board21B projects by a distance L2from the left end surface of the board11B, and the right end surface of the board21B projects by a distance L3from the right end surface of the board11B. Each of the distances L1, L2, and L3may be set to 100 μm, for example. However, the distances L1, L2, and L3may be set to a value other than 100 μm, or to mutually different values, when required. Otherwise, the circuit board module1B illustrated inFIGS. 6A and 6Bis the same as the circuit board module1of the first embodiment illustrated inFIGS. 1A and 1B.

Because the front, left, and right end surfaces of the board21B project more towards the respective side than the front, left, and right end surfaces of the board11B, a size tolerance of the board11B can be ignored, and only a size tolerance of the board21B requires consideration when inserting the circuit board module1B into and extracting the circuit board module1B from the socket90. Hence, the board21B itself can maintain a high alignment function with respect to a fitting or receiving part of the socket90, and it is possible to ensure high positioning accuracy between the circuit board module1B and the socket90. As a result, it is possible to reduce poor electrical connection or electrical connection failure when the circuit board module1B is inserted into the socket90. Otherwise, effects obtainable by the second embodiment are the same as those obtainable by the first embodiment.

First Modification of Second Embodiment

In a first modification of the second embodiment, the circuit board module has an external shape different from that of the second embodiment. In the first modification of the second embodiment, those parts that are the same as those corresponding parts of the embodiments and modification described above are designated by the same reference numerals, and a repeated description of the same parts may be omitted.

FIGS. 8A and 8Bare diagrams illustrating an example of the circuit board module in the first modification of the second embodiment.FIG. 8Aillustrates a plan view of the circuit board module, andFIG. 8Billustrates a cross sectional view of the circuit board module along a line B-B inFIG. 8A.FIG. 9is a perspective view illustrating the example of the circuit board module in the first modification of the second embodiment.

As illustrated inFIGS. 8A, 8B, and 9, a circuit board module1C includes a circuit board10C, and a terminal board20C. The circuit board10C differs from the circuit board10B illustrated inFIGS. 6A, 6B, and 7, in that the circuit board10C uses a board11C in place of the board11B. In addition, the terminal board20C differs from the terminal board20B illustrated inFIGS. 6A, 6B, and 7, in that the terminal board20C uses a board21C in place of the board21B.

An oblique cutout11xillustrated inFIG. 9is provided at each of 2 corners of the board11C at the one end part of the board11C that is inserted into and extracted from the socket90, similarly as in the case of the board11A illustrated inFIG. 5A. On the other hand, an oblique cutout21xillustrated inFIGS. 8A and 9is provided at each of 2 corners of the board21C at the one end part of the board11C that is inserted into and extracted from the socket90, similarly as in the case of the board21A illustrated inFIGS. 4A and 5A. Otherwise, the circuit board module1C illustrated inFIGS. 8A, 8B, and9is the same as the circuit board module1B of the second embodiment illustrated inFIGS. 6A, 6B, and 7.

According to the circuit board module1C, the oblique cutouts11xare provided at the 2 corners of the board11C, and the oblique cutouts21xare provided at the 2 corners of the board21C, at the one end part of the board11C that is inserted into and extracted from the socket90. For this reason, it is possible to reduce damage to the terminal board20C that may occur when the circuit board module1C is frequently inserted into and frequently extracted from the socket90in a repeated manner, for example. Otherwise, effects obtainable by the first modification of the second embodiment are the same as those obtainable by the second embodiment.

Second Modification of Second Embodiment

In a second modification of the second embodiment, the circuit board module has an external shape different from that of the first modification of the second embodiment. In the second modification of the second embodiment, those parts that are the same as those corresponding parts of the embodiments and modifications described above are designated by the same reference numerals, and a repeated description of the same parts may be omitted.

FIG. 10is a plan view illustrating an example of the circuit board module in the second modification of the second embodiment. Illustration of a cross sectional view of the circuit board module in the second modification of the second embodiment will be omitted, since a cross sectional view of the circuit board module along a line B-B inFIG. 10is the same as the cross sectional view illustrated inFIG. 8B.

As illustrated inFIG. 10, a circuit board module1D includes a circuit board10C, and a terminal board20D. The terminal board20D differs from the terminal board20C illustrated inFIGS. 8A, 8B, and 9, in that the terminal board20D uses a board21D in place of the board21C.

In the board21C illustrated inFIGS. 8A and 9, the oblique cutouts21xare provided at the 2 corners of the board21C, at the one end part of the board11C that is inserted into and extracted from the socket90. On the other hand, in the board21D illustrated inFIG. 10, oblique cutouts21xare provided at 4 corners of the board21D. Otherwise, the circuit board module1D is the same as the circuit board module1C illustrated inFIGS. 8A, 8B, and9.

According to the circuit board module1D, the oblique cutouts21xare provided at the 4 corners of the board21D, at the one end part of the board11C that is inserted into and extracted from the socket90. For this reason, it is possible to further reduce damage to the terminal board20D that may occur when the circuit board module1D is frequently inserted into and frequently extracted from the socket90in a repeated manner, for example. Otherwise, effects obtainable by the second modification of the second embodiment are the same as those obtainable by the second embodiment.

Third Embodiment

In a third embodiment, a cavity for mounting a component is provided in the circuit board. In the third embodiment, those parts that are the same as those corresponding parts of the embodiments and modifications described above are designated by the same reference numerals, and a repeated description of the same parts may be omitted.

FIGS. 11A and 11Bare diagrams illustrating an example of the circuit board module in the third embodiment.FIG. 11Aillustrates a partial plan view of the circuit board module in a vicinity of the one end part inserted into the socket, andFIG. 11Billustrates a cross sectional view of the circuit board module along a line C-C inFIG. 11A.

As illustrated inFIGS. 11A and 11B, a circuit board module1E includes a circuit board10E, and a terminal board20. The circuit board10E differs from the circuit board10illustrated inFIGS. 1A, 1B, 2A, and 2B, in that the circuit board10E uses a board11E in place of the board11.

In the circuit board10E, a cavity11yextends from the surface11ntowards the surface11mof the board11E by a predetermined depth as illustrated inFIG. 11B. The cavity11yis defined by inner sidewalls of the board11E, and an inner surface of the board11E forming a bottom part of the cavity11y. The cavity11yis formed in a region where the board11E and the terminal board20overlap in the plan view, as illustrated inFIG. 11A. The cavity11yis used for mounting a component therein. For this reason, the shape of the cavity11yin the plan view, and the depth of the cavity11y, may be appropriately determined according to the shape and size of the component that is to be mounted in the cavity11y.

Component-connection pads16are provided at the bottom part of the cavity11y,and a decoupling capacitor18, for example, is mounted on the component-connection pads16via the bonding material30, as illustrated inFIG. 11B. For example, the component-connection pads16are formed by a pair of mutually separated rectangular pads, to match shapes of terminals of the decoupling capacitor18that is mounted in the cavity11y. The 2 mutually separated rectangular pads forming the component-connection pads16are electrically connected to a power supply pad and a grounding pad, respectively, through via wirings17penetrating the board11E. The power supply pad and the grounding pad form a part of the socket-connection pads22. The power supply pad and the grounding pad are electrically connected, respectively, to a power supply terminal and a ground terminal that are provided in the socket90. Otherwise, the circuit board module1E illustrated inFIGS. 11A and 11Bis the same as the circuit board module1of the first embodiment illustrated inFIGS. 1A, 1B, 2A, and 2B.

According to the circuit board module1E, the cavity11yis provided at the position where the circuit board10E and the terminal board20overlap in the plan view illustrated inFIG. 11A. In addition, the decoupling capacitor18is mounted in the cavity11y, so that the decoupling capacitor18may be arranged at a position close to the power pad forming a part of the socket-connection pads22. As a result, it is possible to reduce noise from a power supply provided on the side of the socket90. Of course, an electronic component other than the decoupling capacitor18may be mounted in the cavity11y. Otherwise, effects obtainable by the third embodiment are the same as those obtainable by the first embodiment.

Modification of Third Embodiment

In a modification of the third embodiment, the cavity for mounting the component is provided in the circuit board at a position different from that of the third embodiment. In the modification of the third embodiment, those parts that are the same as those corresponding parts of the embodiments and modifications described above are designated by the same reference numerals, and a repeated description of the same parts may be omitted.

FIG. 12is a cross sectional view illustrating an example of the circuit board module in the modification of the third embodiment. The cross sectional view illustrated inFIG. 12corresponds to the cross sectional view along the line C-C inFIG. 11A.

As illustrated inFIG. 12, a circuit board module1F includes a circuit board10F, and a terminal board20. The circuit board10F differs from the circuit board10E illustrated inFIGS. 11A and 11B, in that the circuit board10F uses a board11F in place of the board11E.

In the circuit board10F, a cavity11zextends from the surface11mtowards the surface11nof the board11F by a predetermined depth as illustrated inFIG. 12, in contrast to the cavity11yillustrated inFIG. 11Bthat extends from the surface11ntowards the surface11m. The cavity11zis defined by inner sidewalls of the board11F, and an inner surface of the board11F forming a bottom part of the cavity11z.The cavity11zis formed in a region where the board11F and the terminal board20overlap in the plan view. The cavity11zis used for mounting the component therein. For this reason, the shape of the cavity11zin the plan view, and the depth of the cavity11z,may be appropriately determined according to the shape and size of the component that is to be mounted in the cavity11z,similarly as in the case of the cavity11y.

Similarly as in the case of the cavity11yillustrated inFIG. 11B, component-connection pads16are provided at the bottom part of the cavity11z,and a decoupling capacitor18, for example, is mounted on the component-connection pads16via the bonding material30, as illustrated inFIG. 12. For example, the component-connection pads16are formed by a pair of mutually separated rectangular pads, to match shapes of terminals of the decoupling capacitor18that is mounted in the cavity11z. The 2 mutually separated rectangular pads forming the component-connection pads16are electrically connected to a power supply pad and a grounding pad, respectively, through wirings (not illustrated). The power supply pad and the grounding pad form a part of the socket-connection pads22. Otherwise, the circuit board module1F illustrated inFIG. 12is the same as the circuit board module1E of the third embodiment illustrated inFIGS. 11A and 11B.

According to the circuit board module1F, the cavity11zis provided at the position where the circuit board10F and the terminal board20overlap in a plan view. In addition, the decoupling capacitor18is mounted in the cavity11z, so that the decoupling capacitor18may be arranged at a position close to the power pad forming a part of the socket-connection pads22. As a result, it is possible to obtain effects similar to the effects obtainable by the third embodiment.

In addition, according to the circuit board module1F, the decoupling capacitor18may be mounted in the cavity11z, simultaneously as when mounting the electronic components on the surface11mof the board11F, by a reflow process. For this reason, compared to a case in which the decoupling capacitor18is mounted in the cavity11yor the decoupling capacitor18is mounted on the terminal board20, it is possible to reduce the number of reflow processes associated with all of the electronic components to be mounted in the circuit board module1F. As a result, it is possible to reduce risks of failure of the electronic components mounted in the circuit board module1F.

In the case in which the cavity11zis provided, it may no longer be possible to provide a part of the pads121in the center pad column121L of the board-connection pads12, and a part of the pads231in the center pad column231L of the board-connection pads23. But in this case, the self-alignment function can still be exhibited to a satisfactory extent by other pads121in the center pad column121L of the board-connection pads12, and other pads231in the center pad column231L of the board-connection pads23.

According to the embodiments and modifications described above, it is possible to provide a circuit board module which can improve the positional accuracy and the degree of parallelism of the terminal board with respect to the circuit board.

Although the embodiments are numbered with, for example, “first,” “second,” “third,” the ordinal numbers do not imply priorities of the embodiments. Many other variations and modifications will be apparent to those skilled in the art.

For example, each of the pads is not limited to the approximately rectangular shape, and other shapes, such as circular and polygonal shapes may be used for each of the pads. In addition, the circuit board and the terminal board are not limited to those of the embodiments and modifications described above, and may be formed by inorganic boards, flexible boards, or the like.