JP2007013014A - Folding pocket electronic instrument and flexible wiring substrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To permit the reduction of ground potentials between circuit substrates received in respective cabinets, even if the length of an FPC (flexible printed circuit board) becomes large, in a folding type pocket electronic instrument. <P>SOLUTION: The foldable pocket electronic instrument consists of two sets of cabinets 1, 3, accommodating circuit modules, respectively and connected so as to be foldable via a hinge unit 2 while the circuit modules in both cabinets 1, 3 are connected by the FPC 21. The FPC 21 is provided with contacts 44 for ground at an intermediate part in the lengthwise direction thereof, and the contacts 44 are connected to the ground units of the circuit modules. The contacts 44 are connected to a metallic frame 9, serving as the base of the circuit modules and is connected to the ground of the circuit substrate 13, at a plurality of places via a contact plate 24. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an electronic device typified by a mobile phone or a portable information terminal, and in particular, a foldable portable electronic device in which a plurality of casings are connected so as to be foldable, and a circuit incorporated in each of the plurality of casings. The present invention relates to a flexible wiring board used for connecting to a cable.

  A foldable mobile electronic device, for example, a foldable mobile phone, includes a first casing provided with a microphone for transmission, a keypad, and the like, and a second casing provided with a speaker for reception, a display, and the like. The case is connected to the case through a hinge part so as to be rotatable, and the circuit divided and stored in the two cases is connected by a flexible wiring board that is inserted through the hinge part. (See Patent Document 1).

Note that the flexible wiring board has ground layers on both the upper and lower sides of the flexible wiring board in order to suppress unnecessary radiation output from the signal lines and to avoid the influence of radiation disturbance noise. Yes (see Patent Document 2 and Patent Document 3), this type of flexible wiring board is used for circuit connection in a foldable portable electronic device in which a circuit is divided and stored in a plurality of cases.
JP 2003-110210 A Japanese Patent Laid-Open No. 7-170089 JP 2000-165085 A

By the way, when a circuit is divided and stored in a plurality of housings, a difference in ground potential tends to occur between circuit boards housed in each housing, and if the difference is large, the circuit can exhibit desired performance. become unable.
In order to reduce the ground potential difference between the circuit boards housed in each housing, it is desirable that the length of the flexible wiring board (FPC) is short. However, because of the arrangement of components in the housing, the hinge FPC May not be connected to the circuit board near the hinge.
For example, in recent mobile phones with a camera, a camera and an illumination light source are often arranged in the central part of the display side unit on the hinge side. In this case, the display side unit is in the vicinity of the hinge part. Since the FPC cannot be connected to the circuit board, the length of the FPC becomes long and the ground potential difference between the circuit boards housed in the two cases becomes large.

  If a flexible wiring board (FPC) having ground layers on both upper and lower sides is used, the width of the ground layer is slightly improved because it is wide. However, if the length of the FPC is increased, the circuit board is accommodated in two cases. The inconvenience that the ground potential difference between the two becomes large and the circuit cannot exhibit the desired performance still remains.

The above inconvenience is related to folding portable electronic devices in general, but in wireless communication devices such as mobile phones, the antenna characteristics may be further changed and deteriorated depending on the length of the flexible wiring board. is there.
That is, when the power radiation from the antenna is also performed from the housing ground, for example, when the antenna is a quarter wavelength antenna, the ground of the circuit board, the metal module frame, the resin module frame, There is also power radiation from a metal plating portion or the like applied to the housing, and current is also applied to the shield ground of the FPC in the hinge portion, and the antenna characteristics may change and deteriorate depending on the length of the FPC.
In such a case, conventionally, a method of changing the length of the FPC so as not to affect the length has been adopted, but this method requires changing the position of the connector for connecting the FPC to the counterpart board. There is a risk that proper arrangement of the parts will be impaired.

An object of the present invention is to make it possible to reduce a difference in ground potential between circuit boards housed in each housing even when the length of an FPC is increased in a folding portable electronic device. is there.
In addition, the second problem of the present invention is that in a folding portable electronic device having a wireless communication function, when the antenna characteristics are poor, the antenna characteristics are changed by the FPC that connects the circuit boards housed in each housing. (Improvement) is to be able to.

  In order to solve the above-described problems, the invention described in claim 1 is, for example, as shown in FIG. 1 to FIG. In a foldable portable electronic device that is connected so as to be foldable and the circuit modules in both housings 1 and 3 are connected by an FPC 21, a ground contact 44 is provided at an intermediate portion in the longitudinal direction of the FPC 21. Is connected to the ground portion of the circuit module.

  According to the first aspect of the present invention, since the ground contact point provided in the intermediate portion in the longitudinal direction of the FPC is connected to the ground portion of the circuit module, even if the length of the FPC becomes long, The difference in ground potential between the circuit boards to be stored can be reduced.

  A second aspect of the present invention is the foldable portable electronic device according to the first aspect, wherein, for example, as shown in FIG. 3, the contact 44 serves as a base of the circuit module and a plurality of grounds of the circuit board 13. It connects with the metal frame 9 connected in the location, It is characterized by the above-mentioned.

  The invention according to claim 3 is the foldable portable electronic device according to claim 1, wherein the contact 44 is connected to the ground of the circuit board 13, for example, as shown in FIG. 5. .

  Invention of Claim 4 is a foldable portable electronic device as described in any one of Claim 1 to 3, Comprising: As shown, for example in FIGS. 3-5, the said FPC21 is the said circuit module. The copper foil layers on both the upper and lower surfaces are removed except for both the ends to be connected to the connectors 22 and 23 to be connected and the region to be the ground contact 44, and the ground layer 42 is formed with a conductive paste at the removed portion. It is characterized by.

  Invention of Claim 5 is a foldable portable electronic device as described in any one of Claim 1 to 4, Comprising: The said circuit module is provided with the transmission part and / or reception part of a radio signal, It is characterized by the above-mentioned. To do.

  According to the fifth aspect of the present invention, the antenna characteristics can be changed (improved) in the case where the circuit module includes a radio signal transmitting unit and / or receiving unit.

  In the invention described in claim 6, for example, as shown in FIGS. 3 and 5, a ground contact 44 connected to the ground portion of the circuit module is provided in the longitudinal intermediate portion of the FPC 21 connecting the two circuit modules. It is characterized by that.

  The invention according to claim 7 is the FPC according to claim 6, for example, as shown in FIG. 3 to FIG. The copper foil layers on both the upper and lower surfaces are removed except for the region to be the contact 44, and a ground layer 42 is formed with a conductive paste in the removed portion.

According to the present invention, even if the length of the FPC is increased by connecting the ground contact provided in the intermediate portion in the longitudinal direction of the FPC to the ground portion of the circuit module, the circuit board is accommodated in each casing. The difference in ground potential between the two can be reduced.
Therefore, in the foldable portable electronic device, the circuit can exhibit desired performance.
Further, in the case of a foldable portable wireless communication device such as a mobile phone, there is an advantage that the antenna characteristics can be changed (improved).

Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings.
(Embodiment 1)
FIG. 1 shows a mobile phone as a configuration of Embodiment 1 of a foldable portable electronic device to which the present invention is applied. Reference numeral 1 denotes an operation side case, 2 denotes a hinge portion, and 3 denotes a display side case.
The operation-side housing 1 is configured by combining a lower case 1a and an upper case 1b, and an operation unit (various operation keys) 4 and a transmission unit (calling microphone) 5 are provided on the upper case 1b. Although not shown, the operation-side housing 1 includes a circuit board, a circuit module, an antenna, and the like.

As shown in FIG. 2, the display-side housing 3 is configured by combining a lower case 3a and an upper case 3b, and a main display unit (LCD) 6 and a receiving unit (speaking speaker) 7 are provided on the upper case 3b. The sub-display unit (LCD) 8 is provided in the lower case 3a. In the illustrated example, the sub LCD 8 is located in a circular window formed in the lower case 3a.
A metal module frame 9 forming an intermediate case is sandwiched between the lower case 3a and the upper case 3b. As shown in FIGS. 2B and 3, the main LCD 6, the sub LCD 8, the camera module 11, and the like are incorporated in the module frame 9, and a display-side unit on which an illumination light (LED) 12 is mounted. The circuit board 13 is assembled into a module.

Specifically, the sub LCD 8 is incorporated on one side of the module frame 9 and the main LCD 6 and the camera module 11 are incorporated on the other side. Note that an opening communicating with the one side on which the sub LCD 8 is incorporated is formed in the camera unit incorporation portion (housing portion) of the module frame 9, and the sub LCD 8 is incorporated in the lens portion of the camera module 11. It is designed to be exposed on one side.
The circuit board 13 of the display-side unit on which the illumination LED 12 or the like that is an illumination light is mounted is overlapped on the surface side of the module frame 9 including the sub LCD 8 and surrounds the sub LCD 8 and the camera module 11. The illumination LED 12 is located beside the camera module 11.

On one side of the circuit board 13 superimposed on the module frame 9, an FPC 14 connected to the main LCD 6 is connected by a connector, and an FPC 15 connected to the camera module 11 is connected by a connector. Note that an FPC connected to the sub LCD 8 is connected to the back surface of the end of the circuit board 13 opposite to the side on which the illumination LED 12 is provided.
Here, the module frame 9 is connected to the ground (ground) of the circuit board 13 at various places. Further, the circuit board 13 is connected to a connector 16 connected to a circuit module of an operation side unit (not shown) built in the operation side housing 1, that is, a module connection FPC 21 with an operation side circuit module including various key switches. Is provided.
Thus, the circuit module of the display side unit, that is, the display side circuit module is configured.

The module connecting FPC 21 is long in the shape of a strip as shown in the figure, and its middle portion in the longitudinal direction is bent into a loop shape corresponding to the hinge portion 2, and the connector 22 provided at one end is connected to the circuit of the display side circuit module. Connect to the connector 16 of the substrate 13. Further, the connector 23 provided at the other end is connected to a connector of a circuit board of an operation side circuit module (not shown).
A ground contact plate 24 is provided at an intermediate portion in the longitudinal direction of the module connecting FPC 21. As will be described in detail later, the contact plate portion 24 is composed of the FPC 21 itself and is also connected to the ground line of the FPC 21, and has connection holes 24a at both ends protruding in the width direction.
A pair of protrusions 17 are integrally formed on the end surface of the module frame 9 on the camera module 11 side. The pair of protrusions 17 correspond to the connection holes 24 a at both ends of the contact plate portion 24.

FIG. 4 shows a cross section of the FPC 21. FIG. 4A shows a cross section at the signal line portion of the wiring layer, and FIG. 4B shows a cross section at the ground line portion.
As shown in the figure, the FPC 21 has a configuration in which two FPCs are bonded. That is, in the two base films 31, the copper foil layer 32 of the copper foil layers (rolled copper layers) formed on the upper and lower surfaces is patterned as a wiring layer, and the other copper foil layer 36 is connected to the connector mounting portion. Further, the contact plate portion 24 is patterned as described above, a cover lay (protective layer) 33 is laminated on the wiring layer 32, and the cover lay 33 side is bonded to each other with an adhesive layer 34 made of an adhesive. Note that the adhesive is provided only in the region corresponding to the connector mounting portion and the contact plate portion 24, and in the figure, 35 is a region without the adhesive.
The connector attachment portions are formed at both ends in the longitudinal direction of the FPC 21, and a part of the copper foil layer 36 of the connector attachment portion formed on the outer surface of each of the upper and lower two base films 31 is connected to the connector. It is patterned as a terminal portion or a terminal portion for a through hole, and the remaining portion is left as a ground portion for maintaining the strength of the connector mounting portion. Further, in the illustrated example, a terminal portion 38 made of a plated portion is formed on the lower surface copper foil layer 36 where a conductive portion 37 is exposed by a through-hole that penetrates the upper and lower copper foil layers 36 and is electrically connected to each other. 22 and 23 are connected. In addition, the solder resist layer 39 is formed including the other copper foil layers 36 around and around the terminal portion 38.

Further, in order to maintain the flexibility of the FPC, basically, the copper foil layers 36 on the surfaces of the upper and lower base films 31 are removed at the intermediate portion in the longitudinal direction of the FPC 21, and the surfaces of the upper and lower base films 31 are removed. However, in this embodiment, as described above, the copper foil layer 36 in the region to be the contact plate portion 24 is left as the ground copper foil layer 41, and this copper foil is used. A shield layer (ground layer) 42 made of a conductive paste (silver paste) is formed over the entire area where the copper foil layer is removed except for the solder resist layer 39 including the layer 41.
And as shown in FIG.4 (b), the electroconductive part 43 by the through hole which penetrates the upper and lower copper foil layers 41 and mutually conducts is formed. Further, in the illustrated example, a ground contact portion 44 is formed by a plating portion on the copper foil layer 41 on the lower surface side where the conductive portion 43 by the through hole is exposed, and the contact portion 44 is exposed from the shield layer 42.

This contact portion 44 becomes a contact plate of the contact plate portion 24 of the FPC 21 shown in FIG.
A pair of protrusions 17 provided on the end surface on the hinge portion 2 side of the module frame 9 are inserted into the connection holes 24a at both ends protruding from the FPC 21 of the contact plate portion 24 on both sides, so that the contact plate portion 24 is connected to the end surface of the module frame 9. Adhere to the connection.
Then, the connector 22 side of the FPC 21 is drawn under the module frame 9 to the side surface side of the module frame 9, where it is bent to the front side (circuit board 13 side) of the module frame 9 and overlaps the outside of the FPC 15. The connector 22 is connected to the connector 16 on the circuit board 13 by drawing out to the front side of the module frame 9 through the side surface. Further, the connector 23 side of the FPC 21 is bent in a loop shape corresponding to the hinge portion 2, and the connector 23 is connected to the connector of the circuit board of the operation side circuit module (not shown).

As described above, the ground contact portion 44 provided in the middle portion in the longitudinal direction of the module connecting FPC 21 that connects the circuit module in the operation-side casing 1 and the circuit module in the display-side casing 3 of the folding cellular phone. Is connected to the ground portion of the circuit module at the hinge portion 2, the following effects are obtained.
That is, in the embodiment, the module frame 9 that is grounded to the circuit board 13 of the display-side circuit module by the contact plate portion 24 formed in the middle portion in the longitudinal direction of the FPC 21 that connects the operation-side circuit module and the display-side circuit module. Therefore, even if the length of the FPC 21 is increased, the difference in ground potential between the circuit board (not shown) in the operation-side casing 1 and the circuit board 13 in the display-side casing 3 can be reduced. it can.
Therefore, as a foldable mobile phone, the circuit can exhibit desired performance.
In addition, since the position where the contact plate 24 is provided can be changed relatively freely, when the antenna characteristics are deteriorated due to the length of the FPC, the contact plate 24 is provided at an appropriate position and connected to the module frame 9. By doing so, a change (deterioration) in antenna characteristics can be suppressed.

(Embodiment 2)
FIG. 5 shows an example in which the module connecting FPC 21 is directly connected to the circuit board 13 of the display side internal module as a configuration of the second embodiment to which the present invention is applied. The ground contact plate portion 25 to be provided is formed in a bent piece 25b in which both end portions projecting in the width direction extend upward. A connection hole 25a is formed in the bent piece 25b.
In addition, a pair of connection pins 18 are mounted upright on the ground line on the end of the circuit board 13 superimposed on the module frame 9 in the vicinity of the illumination LED 12. The pair of connection pins 18 correspond to the connection holes 25 a of the bent pieces 25 b of the contact plate 25.

A pair of connection pins 18 standing on the end of the circuit board 13 on the side of the hinge part 2 are inserted into the connection holes 25a of the bent pieces 25b protruding from the FPC 21 of the contact plate part 25 and extending upward. Then, the bent piece 25b is held in the connected state to the connection pin 18, and the contact portion 25 is bonded to the end face of the module frame 9 in the connected state.
As described above, even when the ground contact portion 44 provided in the middle portion in the longitudinal direction of the module connecting FPC 21 is directly connected to the ground of the circuit board 13 of the display side circuit module by the contact portion 25, the first embodiment described above. The same effect can be obtained.

In the above embodiment, a cellular phone is used as the folding portable electronic device. However, the present invention is not limited to this, and a notebook personal computer, a PDA (Personal Digital Assistance), a portable wireless communication device, Other portable electronic devices may be used.
Further, in the embodiment, the contact point for ground provided in the intermediate portion in the longitudinal direction of the FPC is connected to the module case or the circuit board of the display side circuit module. It may be connected to a circuit board.
Furthermore, the concrete structure of the FPC ground contact, the connection structure of the contact portion, and the like are arbitrary. For example, although the contact plate portions 24 and 25 are configured by the FPC itself, these may be configured by a metal plate, and the metal plate may be bonded and integrated with the contact portion 44 of the FPC. In addition, it is needless to say that specific detailed structures and the like can be appropriately changed. For example, the antenna only needs to be in at least one housing, and may have any one function of transmission or reception.

BRIEF DESCRIPTION OF THE DRAWINGS It is the perspective view which showed the structure of Embodiment 1 of the foldable portable electronic device to which this invention is applied, and is the perspective view which showed the mobile telephone, and is the figure of open state (a), and the figure of closed state (b). . It is the top view (a) of the display side unit of FIG. 1, and its center sectional drawing (b). It is a disassembled perspective view which shows the example connected to the internal module of FIG. 2, and the module frame of FPC. 4A is a cross-sectional view of the FPC in FIG. 3, and FIG. 4A is a cross-sectional view of a wiring layer at a signal line portion and FIG. 5B is a cross-sectional view of a ground line portion. It is a disassembled perspective view which shows the structure of Embodiment 2 to which this invention is applied, and shows the example connected directly to the circuit board of an internal module and FPC.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Operation side housing | casing 2 Hinge part 3 Display side housing | casing 4 Operation part 5 Transmission part 6 Main display part 7 Reception part 8 Sub display part 9 Module frame 11 Camera module 13 Circuit board 17 Protrusion 18 Connection pin 21 FPC
22/23 Connector 24/25 Contact plate 24a / 25a Connection hole 25b Bending piece 31 Base film 32 Wiring layer 33 Cover lay (protective layer)
34 Adhesive layer 36 Copper foil layer 37 Through hole (conductive part)
38 Terminal part 39 Solder resist layer 41 Copper foil part for ground 42 Shield layer (ground layer)
43 Through hole (conductive part)
44 Contact

Claims (7)

In a foldable portable electronic device in which two casings each incorporating a circuit module are foldably connected via a hinge portion, and the circuit modules in both casings are connected by a flexible wiring board,
A ground contact is provided in the longitudinal intermediate portion of the flexible wiring board,
A foldable portable electronic device characterized in that the contact is connected to a ground portion of a circuit module.   2. The foldable portable electronic device according to claim 1, wherein the contact is connected to a metal frame that serves as a base of the circuit module and is connected to a ground of the circuit board at a plurality of locations.   The foldable portable electronic device according to claim 1, wherein the contact is connected to a ground of a circuit board.   In the flexible wiring board, the copper foil layers on both the upper and lower surfaces are removed except for both ends serving as connector mounting portions to which the circuit module is connected and a ground contact, and a ground layer is formed with a conductive paste on the removed portion. The foldable portable electronic device according to any one of claims 1 to 3, wherein the foldable portable electronic device is formed.   The foldable portable electronic device according to any one of claims 1 to 4, wherein the circuit module includes a wireless signal transmitter and / or receiver.   A flexible wiring board characterized in that a ground contact point for connecting to a ground part of a circuit module is provided at a longitudinal intermediate portion of the flexible circuit board for connecting two circuit modules.   The copper foil layers on both the upper and lower surfaces are removed except for both ends serving as connector mounting portions to which the circuit module is connected and the ground contact points, and a ground layer is formed with a conductive paste in the removed portion. The flexible wiring board according to claim 6.

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