JP2010067491A - Connection structure and electronic device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a connection structure that achieves sure waterproofness, and also to provide an electronic device utilizing the same. <P>SOLUTION: FPCs 22 inside each casing 31, 41 are electrically connected to each other via an FPC 21 and two connecting parts 15. Each substrate 35, 45 executes transfer of signals through each harness part 25, each FPC 22, each connecting part 15, and the FPC 21. A connecting wall 31x is configured by embedding each anisotropic conductor 12 into a part of a casing wall. The anisotropic conductor 12 has conductivity only in the vertical direction of the connecting wall 31x. An ACF 13 is interposed between the connecting wall 31x and the FPCs 21, 22 in the connecting part 15. Each FPC 22 is arranged inside each casing while the FPC 21 is arranged in a slide part 8 outside each casing. Since each FPC does not pass through the opening, waterproof performance is surely secured. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a connection structure for a casing of a mobile terminal, a PDA, a personal computer or the like, and an electronic apparatus including the connection structure.

  Conventionally, an FPC-integrated gasket having a connection structure for a through-hole of a casing of an electronic device such as a portable terminal is known.

1 to 3 of Patent Document 1 disclose an FPC-integrated gasket that is integrated with the FPC 30 and formed in a grommet shape. The FPC integrated gasket 1 is provided with a pair of gaskets 10 made of a rubber-like elastic body. A protrusion 50 that seals the through hole 3 of the housing 2 is provided at the tip of each gasket 10. The protrusion 50 has a tapered surface 53 that is inclined from the cross-sectional area surface 52 larger than the diameter of the through hole 3 of the housing 2 toward the tip surface 54.
In the FPC-integrated gasket, when the protrusion 50 is brought into close contact with the end portion of the through hole 3, water intrusion into the housing 2 is prevented. That is, the pair of gaskets 10 can transmit and receive electrical signals between circuits in each housing 2 while waterproofing the two housings 2.

Patent Document 2 discloses a packing provided so as to sandwich an FPC 15 inserted between a pair of housings, as disclosed in FIGS. Specifically, an annular case packing 7 is mounted between a pair of partial housings constituting the first housing A1. The case packing 7 is obtained by fitting the first and second flexible portion packings sandwiching the FPC 15 with the FPC sandwiched therebetween. Thereby, the FPC integrated gasket formed in the grommet shape integrally with FPC is comprised.
Similarly to the above, an annular case packing 13 is mounted between a pair of partial housings constituting the second housing A2.

Registered Utility Model No. 3127071 JP 2005-32752 A

However, the conventional FPC integrated gasket has the following problems.
In Patent Document 1, there are the following problems. In some cases, the casing and the wiring member are sealed in a thin space between the two casings in the electronic device, such as a slide portion of a sliding portable terminal. In that case, in the above structure, the height dimension of the entire gasket becomes considerably large, so that it is difficult to arrange in such a small gap.

  Patent Document 2 has the following problems. Simply, when an FPC is sandwiched between packings, a gap is always generated. Therefore, the case packing needs to be injection-molded integrally with the FPC, but a special mold or the like is required. Therefore, a new injection mold is required every time the FPC design is changed, and the cost increases. Further, since it is molded integrally with the FPC, the rubber-like elastic material constituting the case packing is limited.

  As described above, as long as the structure in which the wiring member is extended to the inside and outside of the casing through the opening of the casing is adopted, securing waterproofness requires a considerable cost, and the fundamental solution is difficult.

  An object of the present invention is to provide a connection structure that can be reliably waterproofed by providing a structure that can be electrically connected while separately disposing various members inside and outside the housing, and an electronic device using the connection structure. is there.

The connection structure of the present invention has a basic concept of a structure in which members inside and outside the casing are electrically connected through a part of the wall portion of the casing.
For this purpose, a first member having a first conductor is disposed outside the housing of the electronic device. In addition, a second member having a second conductor is disposed inside the housing. Further, a connection wall portion having an anisotropic conductor is provided as a part of the wall portion of the housing. Then, the first conductor and the second conductor are electrically connected via the anisotropic conductor.

  The first and second members having the first and second conductors are not limited to wiring members. The electrodes of the electronic device can also be used as the first and second conductors. Also, when the first and second members are wiring members, they are not limited to flexible printed wiring boards (hereinafter referred to as FPC). In addition to the FPC, there are a rigid printed wiring board (PCB), a flat cable, a micro coaxial cable, and the like. The electrodes of these wiring members can also be used as the first and second conductors.

Thereby, the following effects are obtained.
In this structure, even when the first member is a wiring member, the wiring member does not enter the inside from the outside of the housing. Therefore, it is not necessary to form an opening for passing a wiring member or the like through the housing. Therefore, it is possible to prevent water or the like from entering the housing through the connection structure portion without providing a sealing member.

As a typical example of the connecting wall portion, there is a structure in which a rod-like, granular, or layered anisotropic conductor is formed in the through hole.
Specifically, the rod-like anisotropic conductor is a wire member. The granular anisotropic conductor and the layered anisotropic conductor are formed by electroless plating or the like. In the case of a layered anisotropic conductor, the through hole does not need to be closed. This is because the gap is naturally blocked by the first and second conductors and the adhesive.

  Another typical example of the connecting wall is a structure using an anisotropic conductive adhesive in which conductive particles are dispersed. In this structure, there is no gap from the outside to the inside of the housing in the entire connection structure. Therefore, it is possible to prevent water or the like from entering the housing through the connection structure portion without providing a sealing member.

  A typical example of the first member is an FPC which is an extremely thin wiring member. By using FPC, a highly waterproof connection structure can be provided in an extremely narrow space.

  It is preferable to provide a seal tape or an adhesive layer that covers the first member and the housing. As a result, contact of water or the like with the first conductor of the first member or the anisotropic conductor of the connection wall can be reliably prevented. That is, reliability can be improved.

  The electronic device of the present invention has the above connection structure, and an electronic device having a reliable waterproof structure can be obtained. Typical examples include hinged or sliding portable terminals, digital cameras, personal computers, PDAs and the like.

  According to the connection structure or the electronic device of the present invention, waterproofness can be surely exhibited without providing an opening in the housing.

(Embodiment 1)
FIG. 1 is a perspective view schematically showing the structure of a mobile terminal (electronic device) according to Embodiment 1 of the present invention.
The mobile terminal 1 includes a display unit 3 for displaying various information, an input unit 4, and a slide unit 8. The display unit 3 is provided with a display device 6 using a liquid crystal display panel, a speaker, and the like. The input unit 4 is provided with input keys and a microphone. The slide unit 8 is configured by slidingly fitting an outer frame 8a provided on the display unit 3 side and an inner frame 8b provided on the input unit 4 side.

FIG. 2 is a cross-sectional view illustrating a configuration of a connection portion via the slide portion 8 of the mobile terminal 1 according to the first embodiment.
The display unit 3 is provided with a display unit casing 31 and a display unit substrate 35 as main members. The display unit substrate 35 includes a circuit or the like for sending a display signal to the display device 6. The display unit casing 31 includes a first casing 31a and a second casing 31b that are connected to each other. The first housing 31a is made of a resin such as ABS, PC, PMMA, or an inorganic insulator material.

  The input unit 4 is provided with an input unit housing 41 and an input unit substrate 45 as main members. The input key board 45 includes a circuit for controlling a signal sent from the input key. The input unit housing 41 includes a first housing 41a and a second housing 41b that are connected to each other. And the 1st housing | casing 41a of the input part housing | casing 41 is also comprised by resin, such as ABS, PC, and PMMA, or an inorganic insulator material.

  The slide portion 8 is provided with an FPC 21 (first member) that connects between the connection wall portions 31x and 41x of the housings 31a and 41a. In each of the casings 31a and 41a, wiring bodies 20 that connect the connection wall portions 31x and 41x and the substrates 35 and 45 are provided, respectively. The wiring body 20 includes an FPC 22 (second member) and a harness portion 25 provided at an end portion of the FPC 22. Each harness portion 25 is connected to each substrate 35, 45.

  FIG. 3 is a plan view that virtually shows the wiring path between the harness portions 25. The FPC 21 and each FPC 22 relay signals at the connection unit 15. Therefore, the FPC 22 in the display unit casing 31 and the FPC 22 in the input unit casing 41 are electrically connected via the FPC 21 and the two connection portions 15. Thereby, each board | substrate 35 and 45 is comprised so that transmission / reception of a signal may be performed via each harness part 25, each FPC22, each connection part 15, and FPC21.

As shown in the partial enlarged cross-sectional view of FIG. 2, in the first housing 31 a of the display unit housing 31, the connection portion 15 is provided around the connection wall portion 31 x. Similarly, also in the 1st housing | casing 41a of the input part housing | casing 41, the connection part 15 is provided in the periphery of the connection wall part 41x.
In the connection portion 15, the ACF 13 is interposed between the connection wall portion 31 x and the FPCs 21 and 22. The structure of the ACF 13 will be described later. In the slide portion 8, the FPC 21 and the connection wall portion 31 x are covered with the seal tape 14. Note that the FPCs 21 and 22 are fixed to the first housing 31a by the adhesive layer 16. The adhesive layer 16 ensures alignment between the conductors of the FPCs 21 and 22.

  The connection wall portion 31x is configured by embedding the anisotropic conductor 12 in a part of the housing wall. The anisotropic conductor 12 has conductivity in the vertical direction of the connection wall portion 31x, but does not have conductivity in the horizontal direction. Details of the FPCs 21, 22, ACF 13, and the connection wall 31x will be described below.

FIGS. 4A and 4B are a partial cross-sectional view and a partial cross-sectional view taken along line IVb-IVb, respectively, which further illustrate the partial enlarged cross-sectional view of FIG. 2 in detail. In the figure, the illustration of the sealing tape 14 is omitted for easy viewing.
As shown in the figure, the FPC 21 includes a base film 21a, a circuit layer 21b (first conductor), and a cover lay 21c. Similarly, the FPC 22 includes a base film 22a, a circuit layer 22b (second conductor), and a cover lay 22c. In the connection part 15, the cover films 21c and 22c are removed, and the circuit layers 21b and 22b are exposed.

  As shown in FIG. 4B, the circuit layer 21b of the FPC 21, the circuit layer 22b of the FPC 22, and the anisotropic conductor 12 are aligned with each other. On the other hand, the ACF 13 is called an anisotropic conductive film. As shown in the partial enlarged sectional view of FIG. 4A, the ACF 13 is configured by dispersing the conductive particles 13a in the resin 13b (a state before curing). As the resin 13b of the ACF 13, a repairable resin is used.

When the resin 13b of the ACF 13 is solidified, the connection portion 15 is pressed and solidified. Then, since the conductor particles 13a contact each other only in the vertical direction, anisotropic conductivity is obtained in which the conductive particles 13a are conductive in the vertical direction but are not conductive in the horizontal direction. That is, the circuit layers 21b and 22b of the FPCs 21 and 22 are electrically connected to the anisotropic conductor 12, respectively.
The connection unit 15 in the first housing 41a of the input unit housing 41 is also as described above.

  Examples of the material of the base films 21a and 22a of the FPCs 21 and 22 include polyimide resin, polyester resin, and glass epoxy resin. As the material for the coverlays 21c and 22c, the same material as that for the base films 21a and 22a is generally used. In addition, epoxy resin, acrylic resin, polyimide resin, polyurethane resin, etc. are used.

  The first and second members having the first and second conductors are not limited to wiring members such as FPC. The electrodes of various electronic devices can also be used as the first and second conductors of the connection portion 15. Further, when the first and second members are wiring members, the invention is not limited to the FPC. In addition to the FPC, there are a rigid printed wiring board (PCB), a flat cable, a micro coaxial cable, and the like. The wirings or electrodes of these wiring members can be used as the first and second conductors.

-Method of forming connection 15-
FIGS. 5A to 5D are plan views showing a procedure for forming the connecting portion 15 in the first embodiment. In this example, a procedure for forming the connection portion 15 in the first housing 31a of the display housing 31 will be described.

First, as shown in FIG. 5A, a wide opening through which the FPC passes is not formed in the connection wall portion 31x of the first housing 31a. Next, as shown in FIG.5 (b), the through-hole H is formed in the 1st housing | casing 31a by laser processing or microdrilling. Next, as shown in FIG. 5C, the anisotropic conductor 12 filling the through hole H is formed by electroless plating or the like. Thereafter, as shown in FIG. 5 (d), ACF 13 is applied to the front and back of the connection wall portion 31 x, and the FPCs 21 and 22 are attached onto the ACF 13. Then, the ACF 13 is solidified while pressing the FPCs 21 and 22.
The above procedure is also applied to the formation of the connection portion 15 in the first housing 41a of the input unit housing 41.

  According to the present embodiment, the following effects can be obtained. In the connection portion 15, members such as the FPCs 21 and 22 are electrically connected via the anisotropic conductors 12 of the connection wall portions 31 x and 41 x of the housing. Since the members such as the FPCs 21 and 22 do not need to pass through the wall portion of the housing, the structure for sealing becomes simple. Therefore, it is possible to reliably prevent water or the like from entering the housing (31a, 41a) through the connection portion 15.

In the above embodiment, the ACF 13 is provided, but the ACF 13 is not necessarily required. That is, the circuit layers 21 b and 22 b of the FPCs 21 and 22 may be in direct contact with the anisotropic conductor 12. However, if the ACF 13 is present, the anisotropic conductor 12 and the circuit layers 21 b and 22 b are covered with the resin 13 b of the ACF 13. Therefore, the resin 13b prevents the contact of water or the like to the anisotropic conductor 12 and the circuit layers 21b and 22b.
Therefore, not only the entry of water or the like into the casing, but also the entry of water or the like into a conductor such as a wiring member can be prevented, thereby improving reliability. In a broad sense, the waterproof property includes the reliability of the wiring and the electrode. Therefore, providing the ACF 13 improves the waterproof property.

  As the seal tape 14, what is called a single-sided waterproof tape can be used, for example. For example, there is one in which a butyl rubber, an acrylic pressure-sensitive adhesive, or the like is applied to one side of a base film such as a polyethylene base material, a polyester nonwoven fabric, or an aluminum foil. The seal tape 14 is not always necessary. However, by providing the sealing tape 14, contact of water or the like to the anisotropic conductor 12 and the circuit layers 21b and 22b is more reliably prevented. That is, as described above, reliability, that is, waterproofness is further improved.

(Modified example of arrangement of anisotropic conductor)
FIG. 6 is a plan view showing the positional relationship between the circuit layers 21b and 22b and the anisotropic conductor 12 in a modified example of the arrangement of anisotropic conductors. In this modification, the anisotropic conductor 12 has a structure that can be used for various FPC standards. The anisotropic conductors 12 are not arranged in alignment with the positions of the circuit layers 21b and 22b, but are uniformly distributed. Basically, one or several anisotropic conductors 12 need only exist in the width direction of the circuit layers 21b and 22b. However, it is necessary to avoid contact of a plurality of wirings of the circuit layer 21b (or 22b) with one anisotropic conductor 12 because a short circuit occurs.

Further, there is no problem even if the anisotropic conductor 12 exists in the gap between the wirings of the circuit layers 21b and 22b. If contact with the anisotropic conductor 12 is ensured for each wiring, each wiring is electrically connected without short-circuiting. Further, it is only necessary that each wiring is electrically connected by at least one anisotropic conductor 12.
Furthermore, the diameter of the anisotropic conductor 12 may be made significantly smaller than the wiring width of each circuit layer 21b, 22b.

(Modified example of anisotropic conductor structure)
7A and 7B are cross-sectional views showing modified examples 1 and 2 of the anisotropic conductor.
In Modification 1 shown in FIG. 7A, the cylindrical anisotropic conductor 12 is provided by performing electroless plating on the wall surface of the through hole H. Also in this modified example, since the through hole H is closed by the ACF 13, the sealing function can be maintained.

Modification 2 shown in FIG. 7B is an example in which an anisotropic conductor 12 made of a wire is embedded in a through hole.
In the second modification, the anisotropic conductor 12 and the first housing 31a may be integrally molded by setting a wire in the molding die.

  In any of the above modifications, the FPCs 21 and 22 can be electrically connected through the anisotropic conductor 12. That is, waterproofness can be reliably ensured by performing electrical connection while keeping members such as FPC inside and outside the casing.

(Embodiment 2)
FIGS. 8A and 8B are a partial cross-sectional view in the circuit layer direction of the connection portion 15 in the second embodiment and a partial cross-sectional view taken along the line VIIIb-VIIIb in this order. In the figure, members common to those shown in FIGS. 4A and 4B are assigned the same reference numerals and description thereof is omitted.

In the present embodiment, in the connection portion 15, the entire connection wall portion 31 x is configured by the ACF 13. As described above, the ACF 13 has anisotropic conductivity that exhibits conductivity only in the vertical direction. Therefore, the circuit layers 21 b and 22 b of the FPCs 21 and 22 are electrically connected to each other due to the anisotropic conductivity of the ACF 13. In this example, an anisotropic conductor is constituted by a row of each conductor particle 13a that is in contact with the entire length of the connection wall portion 31x.
Although not shown, the connection portion 15 around the connection wall portion 41x in the first housing 41a of the input unit housing 41 has the same structure.

  The structure shown in FIGS. 8A and 8B is realized by the following procedure, for example. An opening is formed in the first casing 31x in advance, and the ACF 13 is applied to the opening with the FPC 21 attached to the back surface thereof. In this state, as shown in the partially enlarged view of FIG. 7A, the conductor particles 13a are dispersed in the resin 13b.

  Thereafter, the ACF 13 is solidified while pressing the FPC 22 on the ACF 13. Thereby, the row | line | column of each conductor particle 13a which contacted over the whole vertical direction of the connection wall part 31x is formed, and each circuit layer 21b and 22b are electrically connected.

Also in the present embodiment, the FPCs 21 and 22 can be electrically connected through the anisotropic conductor formed of the row of the conductor particles 13a. That is, waterproofing can be reliably ensured by performing electrical connection while keeping members such as FPC inside and outside the housing.
In this embodiment, although it is necessary to form an opening for the connection wall portion in the housing, there is an advantage that the process is simpler than that in the first embodiment.

  Also in the present embodiment, the same seal tape 14 as in the first embodiment may be provided (see FIG. 2).

(Other embodiments)
In each of the above embodiments, the first casings 31a and 41a of the display unit casing 31 and the input unit casing 41 are made of resin, but may be made of metal. In that case, only the connection wall portions 31x and 41x and their peripheral portions may be made of resin or an inorganic insulating material.

  The structure of the embodiment of the present invention disclosed above is merely an example. Therefore, the scope of the present invention is not limited to the scope of these descriptions. The scope of the present invention includes the scope indicated by the recitation of the claims. Furthermore, the scope of the present invention includes all modifications within the meaning and range equivalent to the description of the claims.

  The connection structure of the present invention can be used for electronic devices such as portable terminals, PDAs, personal computers, and digital cameras.

It is a perspective view which shows roughly the structure of the portable terminal which concerns on Embodiment 1 of this invention. 3 is a cross section illustrating a configuration of a connection portion through a slide portion of the mobile terminal according to Embodiment 1. It is a top view which shows virtually the wiring path | route between each harness part. (A), (b) is the partial sectional drawing which further shows in detail the partial expanded sectional view of FIG. 2, and the partial sectional view in the IVb-IVb line in order. (A)-(d) is a top view which shows the formation procedure of the connection part in Embodiment 1. FIG. It is a top view which shows the positional relationship of the circuit layer and anisotropic conductor in the modification of arrangement | positioning of an anisotropic conductor. It is sectional drawing which shows the modifications 1 and 2 of an anisotropic conductor. (A), (b) is the partial sectional view in the circuit layer direction of the connection part in Embodiment 2, and the partial sectional view in a VIIIb-VIIIb line in order.

Explanation of symbols

1 Mobile terminal (electronic equipment)
DESCRIPTION OF SYMBOLS 3 Display part 4 Input part 6 Display apparatus 8 Slide part 8a Outer frame 8b Inner frame 12 Anisotropic conductor 13 ACF
13a Conductor particles 13b Resin 14 Seal tape 15 Connection 16 Adhesive layer 20 Wiring body 21 FPC (first member)
21a Base film 21c Coverlay 21b Circuit layer (first conductor)
22 FPC (second member)
22a Base film 22b Circuit layer (second conductor)
22c cover lay 25 harness part 31 display part case 31a first case 31b second case 31x connection wall part 35 display part substrate 41 input part case 41a first case 41b second case 41x connection wall part 45 input Substrate H Through hole

Claims (7)

A connection structure for electrically connecting a first conductor of a first member arranged outside a housing of an electronic device and a second conductor of a second member arranged inside the housing. ,
Provided as a part of the wall portion of the housing, comprising a connection wall portion containing an anisotropic conductor,
The connection structure in which the first conductor and the second conductor are electrically connected via the anisotropic conductor of the connection wall portion. The connection structure according to claim 1,
The connection wall portion has a structure in which a rod-like, granular, or layered anisotropic conductor is formed in a through-hole penetrating the connection wall portion. The connection structure according to claim 2,
A connection structure in which at least one of the first conductor and the second conductor is electrically connected to the anisotropic conductor via an anisotropic conductive adhesive. The connection structure according to claim 1,
The connection wall part is a connection structure configured by an anisotropic conductive adhesive in which conductive particles are dispersed. In the connection structure as described in any one of Claims 1-4,
The connection structure, wherein the first member is a flexible printed wiring board. In the connection structure according to any one of claims 1 to 5,
A connection structure further comprising a seal tape or an adhesive layer covering the first member and the housing.   The electronic device provided with the connection structure as described in any one of Claims 1-6.

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