JPH04313299A - Mounting structure in electronic apparatus - Google Patents

Abstract

PURPOSE:To provide a mounting structure for an electronic apparatus in which a function of conducting a first electrode to a second electrode and a function of conducting a shielded case with a ground pattern are realized by one member to facilitate assembling. CONSTITUTION:An anisotropically conductive member 30 to be conducted only in a thickness direction is interposed between a first electrode 26 and a second electrode 36, and between a ground pattern 24 and the end face of a shielded case 38.

Description

[Detailed description of the invention]

[Purpose 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 such as a radio device having electronic components that require radio wave shielding.

0002

2. Description of the Related Art Among radio devices, portable radio devices are required to be lightweight and thin, and many small and thin parts are mounted thereon. Among these, in portable radio devices having a liquid crystal display section, thin TAB parts (film carrier parts) are often mounted as parts for driving the liquid crystal.

[0003] These TAB components are mounted on printed wiring boards in a completely different manner from ordinary discrete components or flat package components. Therefore, these TAB
The parts are printed wiring boards (main P) on which normal parts are mounted.
The PC board is mounted on a printed wiring board (referred to as a sub PC board) different from the PC board (referred to as a C board), and the sub PC board after this mounting is attached and connected to the main PC board by some means. This conventional structure will be explained using FIG. 5.

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 the liquid crystal is mounted on the sub PC board 5. On the other hand, on the main PC board 1, discrete components 8 and flat package components other than TAB components are mounted.

A shield case 9 is provided to cover the TAB component 7 in order to shield the TAB component 7. At this time, in order to cover the main PC board 1 with the shield case 9 without any gaps, an elastic packing 13 is provided between the ground pattern 11 of the main PC board 1 and the end face of the shield case 9. Usually elastic packing 1
3 with respect to the main PC board 1, a recess 9a is formed on the end surface of the shield case 9.
An elastic packing 13 is fitted inside a.

[0006] The ground pattern 11 is a through hole 1.
5 to the solid ground 17 on the inner layer of the main PC board 1. Therefore, the shield case 9, elastic packing 13, through hole 15 and solid ground 17 provide TA.
Part B 7 is covered and shielded. On the other hand, the terminal of the connector 3 is electrically connected to the through hole 19, and the through hole 19 is further connected to a circuit section outside the shield case 9 by a pattern 20 provided on another inner layer of the main PC board 1. .

[0007] In this structure, in addition to the process of coupling the connector 3, a process of fitting the elastic packing 13 into the recess 9a of the end face of the shield case and positioning it between the shield case 9 and the ground pattern 11 is required.

Furthermore, a recess 9a for positioning the elastic packing 13 must be formed in the shield case 9, and the end face of the case must be made wider accordingly. For this reason, the thickness of the shield case 9 becomes large, which hinders the reduction in weight and size of the entire radio device.

[0009]

[Problems to be Solved by the Invention] The present invention has been made to solve the above-mentioned drawbacks, and aims to achieve the function of connecting two electrodes and simultaneously connecting the shield case to the earth pattern using a single member. This makes assembly easier, and there is no need to form a recess in the shield case for the shield connection member, making the shield case lightweight and lightweight.
The purpose of the present invention is to provide a mounting structure for electronic equipment that can be made compact. [Structure of the invention]

0010

[Means for Solving the Problems] The present invention provides an anisotropic conductive member that conducts only in the thickness direction between the ground pattern of the first PC board and the end face of the shield case, and between the first electrode and the ground pattern of the first PC board. The above object is achieved by interposing it between the electrode and the second electrode.

[0011]

[Operation] With such a structure, the first and second electrodes can be electrically connected to each other by the anisotropic conductive member, and the shield case can be electrically connected to the ground pattern. Therefore, the above function can be achieved simply by attaching the anisotropic conductive member, making assembly easy.

0012

[Embodiment] An embodiment of the present invention will be explained with reference to the drawings. As shown in FIG. 1, a frame-shaped ground pattern 24 is formed on the surface of a first printed wiring board (hereinafter referred to as a first PC board) 22. A through hole 24a electrically connected to the earth pattern 24 is provided in the area of the earth pattern 24, and a screw insertion hole 24b is also formed. On the other hand, the first electrode 2 is located inside the frame-shaped ground pattern 24.
6 and a through hole 28a connected thereto are provided. Further, a through hole 28b is provided in the outer area of the frame-shaped earth pattern 24, and a through hole 28b
is connected to an electronic component (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 . The anisotropic conductive member 30 has thin metal wires regularly embedded in silicone rubber,
It has the property of being electrically conductive only in the thickness direction and bending in the surface direction.

A TAB component 34 is mounted on one side 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 side. The mounting method for the TAB component 34 is different from the mounting method for discrete components. Therefore, the first
TAB parts 3 are mounted on a second PC board independent of the PC board 22 of
4 has been implemented. The second PC board is arranged such that the second electrode 36 sandwiches the anisotropic conductive member 30, faces the first electrode 26, and is in contact with the other surface of the anisotropic conductive member 30. Ru.

The shield case 38 has screw holes 40 at the four corners.
is provided. The shield case 38 is disposed such that its end surface faces the ground pattern 24 with the anisotropic conductive member 30 in between, and is in contact with the other surface of the anisotropic conductive member 30 . In this state, by inserting the screw 42 into the screw insertion hole 24b and tightening it into the screw hole 40, the first PC board 22
Anisotropic conductive member 30, second printed wiring board 32, and shield case 38 are attached to.

As shown in FIG. 2, which is a cross-sectional view taken along line AA in FIG. 1, the first PC board 22 is a multilayer printed wiring board. The through hole 28a connected to the first electrode 26 is connected to the first P
It is connected to a pattern 25 provided on the inner layer of the C plate 22. Furthermore, the pattern 25 is connected to a through hole 28b located outside the area 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 on the other inner layer of the first PC board 22. In this way, one side of the first PC board 22 is covered with the shield case 38, and the other side is covered with the solid earth of the inner layer of the first PC board 22, and both are connected to the anisotropic conductive member 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 thin metal wires of 0 is sufficiently narrower than the pitch of 1/100, assuming that the frequency used by the radio is 1/100. Therefore, electromagnetic waves are completely prevented from entering and exiting, and the TAB component 34 is shielded.

As shown in FIG. 3, which shows some details of FIG. 2,
The first electrode 26 and the second electrode 36 are in contact with one surface 30a and the other surface 30b of the anisotropic conductive member 30, respectively,
Since they are positioned exactly opposite to each other, electrical conduction occurs through the anisotropic conductive member 30. Further, the shield case 38 is also electrically connected to the ground pattern 24 via the anisotropic conductive member 30. Note that since the anisotropic conductive member 30 does not conduct in any direction other than the thickness direction, there is no possibility that the first and second electrodes 26, 36 and the ground pattern 24 will be short-circuited.

In this way, the anisotropic conductive member 30 is placed between the first electrode 26 and the second electrode 36 and between the ground pattern 2
4 and the end face of the shield case 38, the anisotropic conductive member 30 connects the electrodes and at the same time allows the shield case 38 to be electrically connected to the ground pattern 24. Therefore, since it is only necessary to attach the anisotropic conductive member 30, assembly is easier than in the conventional structure, which requires the work of joining connectors and the work of attaching elastic packing for connecting the shield case.

Furthermore, since the anisotropic conductive member 30 also functions as an elastic packing, the elastic packing becomes unnecessary. Therefore, there is no need to provide a recess on the end face of the case for attaching the elastic packing, and the thickness of the case can be reduced, making it lightweight and compact.

Next, another embodiment will be explained using FIG. 4. A ground pattern 46 is provided in a frame shape on the surface of the first PC board 44, and a first electrode 5 is provided in an area outside the frame.
2 is provided.

The ground pattern 46 is connected to the through hole 48 and the solid ground 54 on the inner layer. 1st PC
An anisotropic conductive member 56 is placed on the plate 44 so that one surface thereof is in contact with the ground pattern 46 and the first electrode 52 . A shield case 62 is attached to the other surface of the anisotropic conductive member 56 with an end surface facing the ground pattern 46 . The second PC board 58 also has a second electrode 60
The second electrode 60 is attached to face the first electrode 52. The parts to be shielded are the second
It is not mounted on the first PC board 58, but is mounted on the first PC board 44 in an area covered by the shield case 62. This embodiment also provides the same functions and effects as those of the above embodiment. Note that the second PC board 58 is not limited to a printed wiring board, and may be an electronic component having electrodes, such as an LCD. Furthermore, by increasing the thickness of the anisotropic conductive member, electronic components can be mounted even in the region of the first PC board facing the second PC board.

[0023]

Effects of the Invention As explained above, in the present invention, since the anisotropic conductive member is provided between the first electrode and the second electrode and between the earth pattern and the end face of the shield case, the anisotropic The conductive member allows the electrodes to be electrically connected to each other and the shield case to the ground pattern at the same time. Therefore, compared to the conventional structure that required two attachments, the connector and the elastic packing, the present invention requires only the attachment of the anisotropic conductive member, making assembly much easier.

Furthermore, since there is no need for an elastic packing to connect the shield case to the ground pattern, there is no need to provide a recess on the end face of the shield case for attaching the elastic packing, and the case can be made thinner and lighter and smaller. can do.

[Brief explanation of drawings]

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

FIG. 2 is a sectional view taken along the line AA in FIG. 1;

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 Earth pattern 26 First electrode
30 Anisotropic conductive member 32 Second printed wiring board
36 Second electrode 38 Shield case

Claims (3)

[Claims] 1. A first printed wiring board having a ground pattern and a first electrode, one surface of which is in contact with the ground pattern and the first electrode, and has conductivity only in the thickness direction. having an anisotropic conductive member and a second electrode,
This second electrode sandwiches the anisotropic conductive member and
a second printed wiring board facing the electrode and in contact with the other surface of the anisotropic conductive member, and having an end surface;
and a conductive case, the end face of which faces the ground pattern while sandwiching the anisotropic conductive member, and is provided in contact with the other surface of the anisotropic conductive member. Mounting structure in electronic equipment. 2. The earth pattern is formed in a frame shape, a first electrode is provided within the frame of the earth pattern, and a second electrode is provided within the frame of the earth pattern.
2. The mounting structure for an electronic device according to claim 1, wherein the printed wiring board is covered by a shield case. 3. A printed wiring board having a ground pattern and a first electrode, and an anisotropic printed wiring board having one surface in contact with the ground pattern and the first electrode and having conductivity only in the thickness direction. It has a conductive member and a second electrode, the second electrode sandwiching the anisotropic conductive member, facing the first electrode, and contacting the other surface of the anisotropic conductive member. a unit provided as a base, and an end face, the end face sandwiching the anisotropic conductive member and facing the ground pattern;
and a conductive case provided in contact with the other surface of the anisotropic conductive member.