Connection structure and electronic apparatus

Abstract

To provide a connection structure and an electronic apparatus, which can increase the number of signal patterns and suppress the number of pins while securing the conduction of a large current.SOLUTION: A connection structure 10 connects a main board 12 and a sub board 34 with a flat cable 38. Each of the main board 12 and the sub board 34 has a receptacle connector 50 and a stud 54 provided in the vicinity of the receptacle connector 50 and electrically connected to a ground. The flat cable 38 has a plug connector 48 fitted to the receptacle connector 50 at a first connection portion 46a with the main board 12, and a ground exposed portion 58 where a part of a ground pattern is exposed. The ground exposed portion 58 is fixed to the stud 54 by a screw 64 and is electrically connected to a top surface 54b of the stud 54.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a connection structure that connects a connection source board and a connection destination with a flat cable, and to an electronic device that includes a board, a connection destination, and a flat cable that connects the board and the connection destination. [Background technology]

[0002] Flat cables such as FPCs are highly flexible and bendable, allowing for a high degree of routing freedom, and are therefore sometimes used in electronic devices such as laptop computers. Flat cables are connected to connectors mounted on electronic circuit boards (see Patent Document 1). Flat cables are sometimes used in connection structures between two circuit boards. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-087383 Summary of the Invention [Problem to be solved by the invention]

[0004] As electronic devices become more sophisticated, the number of signal patterns that need to be transmitted between boards and the current between the two boards tend to increase, which in turn requires an increase in the number of connector pins.Connectors also become larger as the number of pins increases, and when the number of pins exceeds a certain level, there are no commercially available standard products, so a new, dedicated product must be designed, which increases costs.

[0005] The present invention has been made in consideration of the above-mentioned problems, and aims to provide a connection structure and electronic device that can increase the number of signal patterns and reduce the number of pins while ensuring the passage of large currents. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems and achieve the object, a connection structure according to a first aspect of the present invention is a connection structure that connects a connection source board and a connection destination board with a flat cable, wherein the board has a receptacle connector and a stud that is provided near the receptacle connector and is conductive to the ground, the flat cable has a connection part with the board, a plug connector that mates with the receptacle connector, and an exposed ground part where a part of a ground pattern that provides conductivity between the ground of the board and the ground of the connection destination is exposed, the flat cable is fixed to the stud with a screw, and the exposed ground part is provided in a position facing the top surface of the stud and comes into contact with and is conductive with the top surface when the screw is threaded.

[0007] In addition, an electronic device according to a second aspect of the present invention is an electronic device comprising a substrate, a connection destination, and a flat cable connecting the substrate and the connection destination, wherein the substrate has a receptacle connector and a stud provided near the receptacle connector and conducting to the ground, the flat cable has a connection portion with the substrate, a plug connector that mates with the receptacle connector, and a ground exposure portion exposing a part of the ground pattern that provides conduction between the ground of the substrate and the ground of the connection destination, the flat cable is fixed to the stud with a screw, and the ground exposure portion is provided in a position facing the top surface of the stud and comes into contact with and conducts to the top surface when the screw is threaded. [Effects of the Invention]

[0008] According to the above aspect of the present invention, the exposed ground portion of the flat cable is electrically connected to the ground of the board via the stud, ensuring the passage of a large current, and enabling the number of power ground pins on the connector to be reduced or the number of signal patterns to be increased. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a perspective view of a connection structure and an electronic device according to one embodiment of the present invention. [Figure 2] FIG. 2 is a schematic perspective view of the connection structure. [Figure 3] FIG. 3 is an exploded perspective view of the first connection portion. [Figure 4] FIG. 4 is a schematic cross-sectional view of the first connection portion. [Figure 5] FIG. 5 is a schematic diagram of the lower end of the flat cable. [Figure 6] Figure 6 is a connector pinout table. [Figure 7] FIG. 7 is a schematic cross-sectional view of a flat cable according to the first embodiment. [Figure 8] FIG. 8 is a schematic cross-sectional view of a flat cable according to the second embodiment. [Figure 9] FIG. 9 is a schematic cross-sectional view of a flat cable according to a third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a connection structure and an electronic device according to the present invention will be described in detail below with reference to the accompanying drawings. However, the present invention is not limited to these embodiments.

[0011] 1 is a perspective view of a connection structure 10 according to one embodiment of the present invention and an electronic device 11. The electronic device 11 illustrated here is a notebook PC, but the connection structure and electronic device according to the present invention can also be applied to other electronic devices such as tablet PCs, mobile phones, smartphones, or portable game consoles.

[0012] 1 shows a state in which the display housing 22 is opened from the main housing 24 by the hinge 18. As shown in Fig. 1, the electronic device 11 has a configuration in which a connecting edge 22a at the bottom end of the display housing 22 and a connecting edge 24a at the rear end of the main housing 24 are rotatably connected by a pair of left and right hinges 18, 18.

[0013] The main body housing 24 is a thin, rectangular box. A keyboard 26 and a touchpad 28 are provided on the top surface of the main body housing 24. The bottom surface of the main body housing 24 is covered with a bottom cover 30. Inside the main body housing 24, a main board (connection source board) 12, a battery 32, etc. are provided. The main board 12 is a motherboard and controls the entire electronic device 11.

[0014] The main board 12 and the battery 32 are each horizontally elongated and are adjacent to each other in the depth direction within the main body housing 24. A sub-board (connection destination) 34 is provided at the right end portion within the main body housing 24. The sub-board 34 is smaller than the main board 12. An IO connector 36 exposed to the side of the housing is mounted on the sub-board 34. The IO connector 36 is, for example, a USB Type-C. A plurality of chips 34a are mounted on the sub-board 34. The chips 34a are a mixture of 5V power supply types and 3V power supply types.

[0015] The display housing 22 is a horizontally long, flat, rectangular box, and has a display 40 on the front, a rear cover 42 that covers the rear of the display 40, and a bezel 44 that surrounds the periphery of the display.

[0016] Fig. 2 is a schematic perspective view of the connection structure 10. Fig. 2 shows the main housing 24 as seen from below with the bottom cover 30 removed, and is left and right reversed from Fig. 1. In Fig. 2, the battery 32 is shown by an imaginary line.

[0017] The main board 12 and the sub-board 34 are connected by a flat cable 38, which constitutes the connection structure 10. Although the flat cable 38 overlaps with the battery 32 for almost its entire length, the flat cable 38 is thin and therefore has almost no effect on the layout space of the battery 32. The flat cable 38 is an FPC (Flexible Printed Circuits). The main board 12 is connected to the battery 32 and receives a supply of power. The main board 12 is equipped with a power supply circuit, and supplies power to the sub-board 34 via the flat cable 38.

[0018] The connection between the main board 12 and the flat cable 38 is referred to as the first connection portion 46a, and the connection between the sub-board 34 and the flat cable 38 is referred to as the second connection portion 46b. The first connection portion 46a and the second connection portion 46b basically have the same structure. The connection portions 46a and 46b are equipped with a connector 52 consisting of a plug connector 48 and a receptacle connector 50. The connector 52 is a commercially available standard product and is inexpensive. The plug connector 48 is provided on the flat cable 38, and the receptacle connector 50 is mounted on the board side. The connector 52 has an elongated multi-pin shape and is of a vertical mating type. In other words, the plug connector 48 is inserted into and removed from the receptacle connector 50 mounted on the board in a direction perpendicular to the surface of the board.

[0019] The connector 52 at the first connection portion 46a is provided so as to extend laterally along the edge of the main board 12 facing the battery 32. The connector 52 at the second connection portion 46b is provided so as to extend in the depth direction along the edge of the sub-board 34 opposite the IO connector 36. In other words, the orientations of the connectors 52 at the first connection portion 46a and the second connection portion 46b differ by 90 degrees. The flat cable 38 has a U-shaped portion midway to prevent excessive force due to twisting or the like from being applied to the first connection portion 46a and the second connection portion 46b.

[0020] Fig. 3 is an exploded perspective view of the first connecting portion 46a. Fig. 4 is a schematic cross-sectional view of the first connecting portion 46a. Fig. 5 is a schematic view of the lower end of the flat cable 38. Note that the second connecting portion 46b has basically the same structure as the first connecting portion 46a, and therefore is not shown or described here. In addition, the side of the first connecting portion 46a of the flat cable 38 that faces the main board 12 and makes contact with the receptacle connector 50 is referred to as the bottom, and the opposite side is referred to as the top.

[0021] A pair of studs 54 are provided on the main board 12 near both sides of the receptacle connector 50. The studs 54 are made of metal. The studs 54 do not have to be positioned strictly symmetrically relative to the receptacle connector 50 depending on the layout. A pair of studs 54 is preferably provided on both sides of the receptacle connector 50, but one or three or more studs may be provided depending on the conditions. The stud 54 protrudes from a through-hole 12b provided in the main board 12, and on the back side, a flange 54a is in contact with and electrically conductive with the ground pad 12a. The ground pad 12a is electrically conductive with the ground of the main board 12. The flange 54a may be soldered to the ground pad 12a.

[0022] The flat cable 38 transmits and receives signals and supplies power between the main board 12 and the sub-board 34, and may also have a shielding effect depending on the specifications. The flat cable 38 is provided with a power supply pattern and a ground pattern for power supply. The mesh pattern 38a in Figure 5 is part of the ground pattern.

[0023] A plug connector 48 is provided at the end of the flat cable 38, and protrusions 56 protruding laterally are provided on both sides of the mounting portion of the plug connector 48. An exposed ground portion 58 that is electrically connected to a ground pattern such as the mesh pattern 38a is provided on the underside of the tip of the protrusion 56. The exposed ground portion 58 is electrically connected to the ground pattern within the flat cable 38. The exposed ground portion 58 is not covered with an insulating coating, and the metal surface is exposed. In other words, the exposed ground portion 58 is a portion where a part of the ground pattern (such as the mesh pattern 38a) that electrically connects the ground of the main board 12 and the ground of the sub-board 34 is exposed. In Figure 4, the exposed ground portion 58 is indicated by a dotted background.

[0024] The exposed ground portion 58 is located opposite the top surface 54b of the stud 54, and comes into contact with and is electrically conductive to the top surface 54b when a screw 64, described below, is threaded into the exposed ground portion 58. The exposed ground portion 58 has the same circular shape as the top surface 54b, but may also be U-shaped. The exposed ground portion 58 and the top surface 54b have areas that are significantly larger than the areas of the pins of the connector 52. A screw hole 58a is formed in the center of the exposed ground portion 58. The exposed ground portion 58 is basically formed on the bottom surface, but an exposed portion may also be formed on the top surface to be electrically conductive to the bracket 60, described next.

[0025] Two brackets 60, 62 are stacked on the top surface of the flat cable 38. Two screw holes 60a, 62a corresponding to the screw holes 58a are formed in the brackets 60, 62, respectively. Two positioning protrusions 60b are formed at positions slightly apart in the bracket 60. Two positioning holes 62b into which the positioning protrusions 60b fit are formed in the bracket 62. The bracket 60 is fixed to the flat cable 38 with adhesive tape or the like, and is substantially integrated with the flat cable 38.

[0026] The flat cable 38 is fixed in place by the mating force of the plug connector 48 to the receptacle connector 50, and is also secured together with the brackets 60 and 62 by two screws 64 passing through screw holes 62a, 60a, and 58a and threadedly engaging with the stud 54. The brackets 60 and 62 hold down the end face of the plug connector 48, reliably preventing it from coming loose. The flat cable 38 is reliably secured by the screws, and the exposed ground portion 58 is pressed firmly against the top surface 54b of the stud 54, ensuring good electrical continuity.

[0027] Figure 6 is a pin layout table for connector 52. As shown in Figure 6, connector 52 has 21 pins. Pins 1, 4, and 7 are grounds. Pins 2 and 3 are high-speed transmit signals. Pins 5 and 6 are high-speed receive signals. Pin 8 is the first logic signal. Pin 9 is the second logic signal. Pins 11 to 13 are +5V power supplies. Pins 15 to 20 are +3V power supplies. Pins 10, 14, and 21 are unused to ensure spacing. Of these, the grounds for pins 1, 4, and 7 are located near the high-speed transmit signals and high-speed receive signals to ensure high-speed signal transmission quality, and serve primarily as signal grounds.

[0028] Because the sub-board 34 is equipped with multiple chips 34a and requires a fairly large current, three pins are assigned to +5V and six to +3V, providing a total of nine power pins. As mentioned above, pins 1, 4, and 7 are essentially signal grounds, so in reality, nine additional pins, the same number as the power pins, would be provided for power grounds corresponding to +5V and +3V. In other words, conventionally, the connector used to connect the main board 12 and the sub-board 34 has a 30-pin (=21+9) specification. In some cases, a standard 30-pin specification product is not available commercially, necessitating the use of an expensive dedicated product.

[0029] In contrast, in the connection structure 10 and electronic device 11 of this embodiment, the ground of the flat cable 38 is electrically connected to the ground of the circuit board via the appropriately large exposed ground portion 58 and stud 54. Furthermore, the screw fastening between the two provides a moderately strong surface pressure, resulting in low contact resistance. This portion essentially serves as the power supply ground, allowing the connector 52 to be a 21-pin connector, fewer than the conventional specifications. This means that the number of pins can be reduced while still ensuring the passage of a large current. Furthermore, by reducing the number of pins required for the ground, it is possible to increase the number of signal patterns accordingly. Furthermore, even when a standard 30-pin connector is available, the 21-pin connector is usually cheaper and smaller.

[0030] Examples of the flat cable 38 are described below. Flat cables 38 are often of the microstrip type or strip type, which are made up of multiple layers. The microstrip type has a ground plane on one side and a signal line on the other side, sandwiched between an insulating layer. This is mainly a double-sided FPC. The strip type has a structure in which the signal line is sandwiched between ground planes on both sides, with an insulating layer in between. This is mainly a multi-layer FPC with three or more layers.

[0031] The ground patterns of the flat cable 38 can be broadly divided into two types. One type is provided in multiple locations on the same layer as the signal pattern S (see FIGS. 7 and 8), and has approximately the same width as the signal pattern S. This is referred to as the first ground pattern Ga. The other type is provided so as to overlap the signal pattern S on another layer and cover almost the entire surface. This is referred to as the second ground pattern Gb. The second ground pattern Gb is also called a solid ground.

[0032] The first ground pattern Ga is used as a signal ground and power ground, and has a relatively large current. The second ground pattern Gb basically provides a shielding effect due to its large area. Furthermore, the faster the signal pattern S, the more its return tends to flow through the second ground pattern Gb directly below it, so the second ground pattern Gb also functions as a return path for high-speed signals. Although the second ground pattern Gb has a large area, the current is relatively small because it functions as a shielding effect and a high-speed return path.

[0033] 7 is a schematic cross-sectional view of a flat cable 38A according to a first embodiment. The flat cable 38A is a two-layer microstrip type using both sides, with a signal pattern S and a first ground pattern Ga provided on one side and a second ground pattern Gb covering the entire other side.

[0034] 8 is a schematic cross-sectional view of a flat cable 38B according to the second embodiment. The flat cable 38B is a three-layer strip type, with a signal pattern S and a first ground pattern Ga provided on the middle layer, and the entire top and bottom layers being covered with a second ground pattern Gb.

[0035] Fig. 9 is a schematic cross-sectional view of a flat cable 38C according to a third embodiment. The flat cable 38C is an irregular three-layer strip type. In the left half of Fig. 9, the flat cable 38C has a signal pattern S and a first ground pattern Ga in the middle layer, and a second ground pattern Gb in the top and bottom layers. In the right half of Fig. 9, the middle layer has the second ground pattern Gb, and the signal pattern S and the first ground pattern Ga are in the top and bottom layers. In this way, the first ground pattern Ga is not necessarily located on the same layer as the signal pattern S; the second ground pattern Gb may also be located on the same layer as the signal pattern S.

[0036] Consequently, the first ground pattern Ga can be identified as being in the same layer as the signal pattern S, but not overlapping with the signal pattern S on other layers. The second ground pattern Gb can also be identified as being in an overlapping position with the signal pattern S on other layers, in order to provide a shielding effect.

[0037] As described above, the exposed ground portion 58 functions as a power supply ground and allows a large current to flow. On the other hand, the first ground pattern Ga needs to allow a relatively large current to flow. Therefore, the exposed ground portion 58 is electrically connected to at least the first ground pattern Ga within the flat cable 38, ensuring the current capacity of the first ground pattern Ga.

[0038] The connection destination of the flat cable 38, which has the main board 12 as its connection source, is not limited to the sub-board 34, but may also be, for example, a chip or a sensor mounted on the flat cable 38. The connection destination of the flat cable 38, which has the main board 12 as its connection source, is not limited to one, but the flat cable 38 may branch and be connected to multiple devices.

[0039] The present invention is not limited to the above-described embodiment, and can of course be freely modified within the scope of the gist of the present invention. [Explanation of symbols]

[0040] 10. Connection structure 11 Electronic equipment 12 Main board (connection source board) 32 Battery 34 Sub-board (connection destination) 34a Chip 36 IO connectors 38, 38A, 38B, 38C flat cable 46a First connection part 46b Second connection part 48 plug connector 50 receptacle connector 52 connectors 54 studs 54a flange 54b Top surface 58 Ground exposure 60,62 bracket Ga 1st ground pattern Gb Second ground pattern

Claims

1. A connection structure that connects a connection source substrate and a connection destination with a flat cable, The substrate is a receptacle connector; a stud provided near the receptacle connector and electrically connected to a ground; and The flat cable is connected to the board, a plug connector that mates with the receptacle connector; a ground exposure portion in which a part of a ground pattern that electrically connects the ground of the substrate and the ground of the connection destination is exposed; and The flat cable is fixed to the stud by a screw, The exposed ground portion is provided at a position facing the top surface of the stud, and is in contact with the top surface and is electrically connected when the screw is threaded. A connection structure characterized by:

2. 2. The connection structure according to claim 1, the flat cable is made up of multiple layers, and includes a first ground pattern provided in the same layer as a layer having a signal pattern and arranged so as not to overlap with signal patterns in other layers, and a second ground pattern arranged so as to overlap with signal patterns in other layers, The exposed ground portion is electrically connected to at least the first ground pattern within the flat cable. The connection structure according to claim 1 .

3. 2. The connection structure according to claim 1, the connector consisting of the receptacle connector and the plug connector is of a vertical mating type, The stud and the exposed ground portion are provided in pairs on both sides of the connector, The end faces of the plug connector are held down by brackets whose both ends are fastened together with the exposed gland portions by the screws. The connection structure according to claim 1 .

4. 2. The connection structure according to claim 1, A second connection portion formed by the flat cable and the connection destination has the same structure as a first connection portion formed by the flat cable and the substrate. The connection structure according to claim 1 .

5. An electronic device comprising a connection source substrate, a connection destination, and a flat cable connecting the substrate and the connection destination, The substrate is a receptacle connector; a stud provided near the receptacle connector and electrically connected to a ground; and The flat cable is connected to the board, a plug connector that mates with the receptacle connector; a ground exposure portion in which a part of a ground pattern that electrically connects the ground of the substrate and the ground of the connection destination is exposed; and The flat cable is fixed to the stud by a screw, The exposed ground portion is provided at a position facing the top surface of the stud, and is in contact with the top surface and is electrically connected when the screw is threaded. An electronic device characterized by:

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