JP2904449B2 - Mounting structure in electronic equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

 [Object of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mounting structure for an electronic device having an electronic component requiring a radio wave shield such as a wireless device.

[0002]

2. Description of the Related Art A small number of small and thin components are mounted on a portable wireless device which is required to be lightweight and thin.
Among them, in a portable wireless device having a liquid crystal display unit, a thin TAB component (film carrier component) is often mounted as a component for driving a liquid crystal.

[0003] These TAB components are mounted on a printed wiring board in a completely different manner from ordinary discrete or flat package components. Therefore, these TAB
The components are printed wiring boards (main P
The printed circuit board is mounted on a printed wiring board (referred to as a sub-PC board) different from the printed circuit board (referred to as a C-board), and the mounted sub-PC board is attached and connected to the main PC board by some means. This conventional structure will be described with reference to FIG.

A sub-PC board 5 is attached to the main PC board 1 via a pair of male and female connectors 3. A TAB component 7 for driving liquid crystal is mounted on the sub-PC board 5. On the other hand, discrete components 8 and flat package components other than TAB components are mounted on the main PC board 1.

[0005] In order to shield the TAB component 7, a shield case 9 is provided so as to cover the TAB component 7. At this time, an elastic packing 13 is provided between the ground pattern 11 of the main PC board 1 and an end face of the shield case 9 so as to cover the shield case 9 with no gap on the main PC board 1. Normally, elastic packing 1
A recess 9 a is formed in the end surface of the shield case 9 for positioning the base 3 with respect to the main PC board 1.
The elastic packing 13 is fitted in a.

The ground pattern 11 is a through hole 1
5 is connected to a solid ground 17 on the inner layer of the main PC board 1. Therefore, the TA is formed by the shield case 9, the elastic packing 13, the through hole 15, and the solid ground 17.
The B component 7 is covered and shielding is performed. On the other hand, the terminals of the connector 3 are electrically connected to the through holes 19, and the through holes 19 are connected to a circuit part outside the shield case 9 by a pattern 20 provided in another inner layer of the main PC board 1. .

In this structure, in addition to the step of connecting the connector 3, a step of fitting the elastic packing 13 into the concave portion 9a on the end face of the shield case and positioning it between the shield case 9 and the ground pattern 11 is required.

Further, a concave portion 9a for positioning the elastic packing 13 must be formed in the shield case 9, and the end face of the case needs to be widened accordingly. For this reason, the thickness of the shield case 9 is increased, which hinders the weight reduction and downsizing of the entire wireless device.

[0009]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned drawbacks, and is to realize a function of connecting two electrodes and simultaneously conducting a shield case to an earth pattern with one member. As a result, the assembly is easy and the shield case is lightweight without forming a recess for the shield connection member in the shield case.
An object of the present invention is to provide a mounting structure in an electronic device that can be reduced in size. [Configuration of the Invention]

[0010]

According to the present invention, one anisotropic conductive member that conducts only in the thickness direction is provided between the ground pattern of the first PC board and the end face of the shield case and between the first electrode and the first electrode. The above-mentioned object is achieved by interposing between the second electrode and the second electrode.

[0011]

With this configuration, the first and second electrodes can be electrically connected and the shield case can be electrically connected to the ground pattern by the anisotropic conductive member. Therefore, the above-mentioned function can be achieved only by attaching the anisotropic conductive member, so that the assembling becomes easy.

[0012]

Embodiments of the present invention will be described with reference to the drawings. As shown in FIG. 1, a ground pattern 24 is formed in a frame shape on the surface of a first printed wiring board (hereinafter, referred to as a first PC board) 22. In the area of the ground pattern 24, a through hole 24a that is electrically connected to the ground pattern 24 is provided, and a screw insertion hole 24b is formed. On the other hand, the first electrode 2
6 and a through hole 28a connected thereto. A through hole 28b is provided in an outer region of the frame-shaped ground pattern 24.
Are connected to electronic components (not shown).

One surface of the anisotropic conductive member 30 laminated on the first PC board 22 is brought into contact with the ground pattern 24 and the first electrode 26. In the anisotropic conductive member 30, fine metal wires are regularly embedded in silicon rubber,
It has the property of conducting only in the thickness direction and bending in the surface direction.

A TAB component 34 is mounted on one surface of a second printed wiring board (hereinafter, referred to as a second PC board) 32, and a second electrode 36 is printed on the other surface. The mounting method of the TAB component 34 is different from the mounting method of the discrete component. Therefore, the first mounting of discrete components
TAB parts 3 on a second PC board independent of PC board 22
4 are implemented. The second PC board is arranged such that the second electrode 36 is opposed to the first electrode 26 with the anisotropic conductive member 30 interposed therebetween and is in contact with the other surface of the anisotropic conductive member 30. You.

The shield case 38 has screw holes 40 at four corners.
Is provided. The shield case 38 is arranged such that its end face faces the ground pattern 24 with the anisotropic conductive member 30 interposed therebetween and contacts the other surface of the anisotropic conductive member 30. In this state, the screw 42 is inserted into the screw insertion hole 24b and tightened into the screw hole 40, so that the first PC board 22
The anisotropic conductive member 30, the second printed wiring board 32, and the shield case 38 are attached thereto.

As shown in FIG. 2 showing a cross section taken along line AA of FIG. 1, the first PC board 22 is a multilayer printed wiring board. First
The through holes 28 a connected to the electrodes 26 are connected to the patterns 25 provided in the inner layer of the first PC board 22. Further, the pattern 25 is connected to a through hole 28b located outside a region surrounded by the shield case 38.

On the other hand, the through hole 24b connected to the ground pattern 24 is connected to a solid ground 23 provided in another inner layer of the first PC board 22. As described above, one side of the first PC board 22 is covered by the shield case 38, and the other side is covered by the solid ground of the inner layer of the first PC board 22, and both are covered by the anisotropic conductive members 30,
Since they are connected via the ground pattern 24 and the through hole 24a, they have the same potential. Moreover, the anisotropic conductive member 3
The pitch of the fine metal wire of 0 is sufficiently narrower than the input / 100 when the operating frequency of the radio is input. Therefore, ingress and egress of electromagnetic waves are completely prevented, and the TAB component 34 is shielded.

As shown in FIG. 3 showing a part of FIG. 2 in detail,
The first electrode 26 and the second electrode 36 contact one surface 30a and the other surface 30b of the anisotropic conductive member 30, respectively.
Since they are positioned directly opposite each other, conduction is achieved through the anisotropic conductive member 30. The shield case 38 is also electrically connected to the ground pattern 24 via the anisotropic conductive member 30. Since the anisotropic conductive member 30 does not conduct except in the thickness direction, there is no possibility that the first and second electrodes 26 and 36 and the ground pattern 24 are short-circuited.

As described above, the anisotropic conductive member 30 is provided between the first electrode 26 and the second electrode 36 and the ground pattern 2.
4 and the end face of the shield case 38, the electrodes can be connected to each other by the anisotropic conductive member 30 and the shield case 38 can be electrically connected to the ground pattern 24 at the same time. Accordingly, since it is only necessary to attach the anisotropic conductive member 30, the assembly becomes easier as compared with a structure in which the joining operation of the connector and the attaching operation of the elastic packing for connecting the shield case are conventionally required.

Further, since the anisotropic conductive member 30 also functions as the elastic packing, the elastic packing becomes unnecessary. Therefore, it is not necessary to provide a concave portion for mounting the elastic packing on the end face of the case, and the thickness of the case can be reduced.

Next, another embodiment will be described with reference to FIG.
An earth pattern 46 is provided in a frame shape on the surface of the first PC board 44, and the first electrode 5 is provided in an area outside the frame.
2 are provided.

The ground pattern 46 is connected to the through hole 48 and the inner solid ground 54. First PC
On the plate 44, one surface of the anisotropic conductive member 56 is arranged so as to contact the ground pattern 46 and the first electrode 52. The other surface of the anisotropic conductive member 56 is attached with the end surface of the shield case 62 facing the ground pattern 46. The second PC plate 58 is provided with a second electrode 60.
And the second electrode 60 is attached in a state where the second electrode 60 faces the first electrode 52. Parts to be shielded are second
Is mounted on the first PC board 44 and in a region covered by the shield case 62. According to this embodiment, the same operation and effect as those of the above embodiment can be obtained. Note that the second PC board 58 is not limited to a printed wiring board, and may be an electronic component having electrodes, for example, an LCD. In addition, by increasing the thickness of the anisotropic conductive member, it is possible to mount electronic components also in the area of the first PC board facing the second PC board.

[0023]

As described above, in the present invention, the anisotropic conductive member is provided between the first electrode and the second electrode and between the ground pattern and the end face of the shield case. The shield case can be electrically connected to the ground pattern at the same time as the electrodes are electrically connected by the conductive member.
Therefore, in contrast to the conventional structure requiring two attachments of the connector and the elastic packing, the present invention requires only the attachment of the anisotropic conductive member, so that the assembling becomes much easier.

Further, since the elastic packing for connecting the shield case to the ground pattern is not required, there is no need to provide a concave portion for mounting the elastic packing on the end face of the shield case, and the thickness of the case can be reduced, and the case can be reduced in weight and size. can do.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view illustrating an embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is an enlarged view of a part of FIG. 2;

FIG. 4 is a diagram illustrating another embodiment of the present invention.

FIG. 5 is a diagram illustrating a conventional example.

[Explanation of symbols]

 22 First Printed Wiring Board 24 Ground Pattern 26 First Electrode 30 Anisotropic Conductive Member 32 Second Printed Wiring Board 36 Second Electrode 38 Shield Case

Continuation of the front page (56) References JP-A-1-125897 (JP, A) JP-A-3-265186 (JP, A) JP-A-64-73794 (JP, A) Jpn. , U) Japanese Utility Model Showa 58-95097 (JP, U) Japanese Utility Model Showa 62-94379 (JP, U) Japanese Patent Publication No. 37-31965 (JP, B1) (58) Fields surveyed (Int. Cl. ⁶ , DB Name) H05K 9/00

Claims (3)

(57) [Claims] A first printed wiring board having an earth pattern and a first electrode; and a first printed wiring board having the earth pattern and the first electrode.
An anisotropic conductive member having one surface in contact with the first electrode and having conductivity only in the thickness direction; and a second electrode, the second electrode sandwiching the anisotropic conductive member. A second printed wiring board provided opposite to the first electrode and in contact with the other surface of the anisotropic conductive member; and an end surface, the end surface comprising the anisotropic conductive member. And a conductive case provided in contact with the ground pattern and in contact with the other surface of the anisotropic conductive member. 2. The ground pattern is formed in a frame shape, a first electrode is provided in the frame of the ground pattern, and the second printed wiring board is covered by a shield case. 2. A mounting structure in the electronic device according to 1. 3. A printed wiring board having an earth pattern and a first electrode, and an anisotropic film having one surface in contact with the earth pattern and the first electrode and having conductivity only in a thickness direction. A conductive member and a second electrode;
A unit provided opposite to the first electrode with the anisotropic conductive member interposed therebetween and in contact with the other surface of the anisotropic conductive member; A conductive case provided opposite to the ground pattern with the anisotropic conductive member interposed therebetween and in contact with the other surface of the anisotropic conductive member. Mounting structure.