JPH02156597A - Shield structure of printed wiring board - Google Patents

Abstract

PURPOSE:To mount circuit parts on a printed wiring board at a high packaging density so as to reduce the size and increase the signal transmitting speed of the board by constituting shielding plates provided with leg pieces to be passed through through-holes of the board to have a shielding structure to be mounted on the mounting surface side of the board. CONSTITUTION:Shielding plates 20 are mounted on a printed wiring board 1 in a state where main plate members 21 of the plates 20 are mounted on the mounting surface side of the board 1, with leg pieces 25 of the plates 20 being passed through slit-type through holes 2 formed in the board 1 along partitioning lines, and upper-side edges 22 of the plates 20 are firmly adhered to an upper cover 10. Front end sections of the leg pieces 25 are put in and firmly adhered to slits 16 formed in a lower cover 15. Thus circuit parts which are mounted on the board 1 and may cause electro-magnetic interference with each other are completely partitioned and shielded from each other by the main plate members 21. Therefore, even when circuit parts are mounted on one printed wiring board at a high packaging density, the possibility of the interference between the parts can be eliminated. Moreover, the printed circuit board thus manufactured can be reduced in line length and improved in signal transmitting speed as compared with the circuit board using connectors, etc., for connection.

Description

[Detailed Description of the Invention] ((Existing) A shield structure for a printed wiring board housed in a metal case, which enables high-density mounting of circuit components, is small in size, is low in cost, and is capable of increasing signal speed. The purpose of this electronic device is to provide a shielding structure for a printed wiring board that does not cause any obstruction. It has a lower edge that abuts the mounting surface of the board, an upper edge that abuts the inner surface of the core cover, and a lateral edge that abuts the inner wall of the frame board, and the upper edge of the mounting surface of the printed wiring board is arranged as desired. A shield plate is provided on the printed wiring board, and includes a main board member for partitioning, and a crosspiece disposed on the lower edge of the printed wiring board so as to pass through slit-shaped through holes arranged along the partition line of the printed wiring board. When installed, the leg piece is fixed to the slit-shaped through hole, the distal edge of the leg piece to the lower cover, and the upper edge of the leg piece to the supranuclear cover, respectively, by soldering or conductive adhesive. The configuration is as follows.

[Industrial application field]

The present invention relates to a shield structure for a printed wiring board housed in a metal case.

[Conventional technology]

2. Description of the Related Art Printed wiring boards used in recent electronic devices have become susceptible to mutual interference in signal circuits within the printed wiring board due to higher signal speeds and higher density mounting of circuit components. When components with long lead terminals are mounted on a printed wiring board, mutual interference is particularly likely to occur, so it is necessary to provide the electronic device with a shield structure.

Therefore, in conventional printed wiring boards where mutual interference may occur, the printed wiring boards are completely divided into two or three pieces, and each is housed in a separate metal case or the like for shielding.

The divided printed wiring boards are connected to each other via connectors.

[Problems to be Solved by the Invention] However, in the conventional shielding means described above, the printed wiring board is divided, housed in separate metal cases, etc., and connected with connectors, etc., so that it is difficult to miniaturize and increase the speed of electronic devices. There was a risk that this would not only be a hindrance to the project, but also lead to higher costs.

The present invention was created in view of these points, and is a shield for printed wiring boards that enables high-density mounting of circuit components, is small in size, is low in cost, and does not impede high-speed signal transmission. The purpose is to provide structure.

[Means to solve the problem]

In order to achieve the above object, the present invention provides an upper cover 10. Lower cover 15. In an electronic device in which a printed wiring board 1 is horizontally housed in a metal case consisting of a frame plate 5, a shield plate 20 is provided on the mounting surface side of the printed wiring board 1.
Attach.

The shield plate 20 has a lower edge 23 that contacts the mounting surface of the printed wiring board 1 and an upper edge 22 that contacts the inner surface of the upper cover 10.
, has a lateral edge that abuts the inner wall of the frame board 5, and has a printed wiring board 1
A main plate member 2l-L21-2 that partitions the upper part of the mounting surface as desired.
．． 21-3, a projection 24 arranged on the upper edge 22, and a leg piece 25 arranged on the lower edge 23 so as to pass through the slit-shaped through holes 2 arranged on the partition line of the printed wiring board l.
It consists of

Then, the base portion of the leg piece 25 is fixed to the slit-shaped through hole 2 by soldering or using a conductive adhesive.

Further, the tip end edge of the leg piece 25 is inserted into the slit 16 parallel to the lower cover 15 and fixed to the lower cover 15 by soldering or using a conductive adhesive.

On the other hand, the protrusions 24 are inserted into the holes 11 parallel to the upper cover IO and fixed to the upper cover 10 by soldering or using a conductive adhesive.

[Effect]

The main plate portion 21 of the shield plate 20 is attached to the mounting surface side of the printed wiring board 1, and the leg pieces 25 are fixed through the slit-shaped through holes 2 arranged on the partition line, and the tip edge of the leg piece 25 is fixed. Place the upper edge 22 on the lower cover 15 and the upper cover 1.
0, respectively. Therefore, circuit components mounted on the printed wiring board 1 that are likely to electromagnetically interfere with each other are completely partitioned and shielded by the main board member 21. In other words, even if circuit components are mounted at high density on two printed wiring boards, there is no risk of mutual interference.

In addition, since each partitioned area is connected by a pattern on the back side of the printed wiring board or a pattern in the inner layer, which is formed in a position avoiding the slit-shaped through hole 2, it is compared to a connector connection etc. Since the line length is short, it does not become an obstacle to increasing the signal speed.

Note that since the space on the back side of the printed wiring board 1 is also partitioned by the leg pieces 25 arranged in a shelf shape, a considerable shielding effect can be expected on the back side of the printed wiring board.

(Example) The present invention will be specifically described below with reference to the drawings.The same reference numerals indicate the same objects throughout the drawings.

FIG. 1 is an isolated perspective view of an embodiment of the invention, and FIG. 2 is a cross-sectional view of an embodiment of the invention.

1 and 2, printed wiring board 1 includes upper cover 10. Lower cover 15. It is configured to be housed horizontally in a metal case consisting of a frame plate 5 and a frame plate 5. In detail,
Desired portions of each side wall of the frame plate 5 are pressed and cut and raised inward, and several supporting pieces 6 are provided horizontally.

Then, the printed wiring board 1 is inserted horizontally into the frame board 5, supported by the support piece 6, and the support piece 6 and the ground pattern part of the printed wiring board 1 are soldered, with the mounting surface facing up. The printed wiring board 1 is housed and mounted within the frame board 5.

Further, in the metal case, a lower cover 15 made of a metal plate is attached to the lower opening of the frame plate 5, and an upper cover 10 made of a metal plate is attached to the upper opening.

On the other hand, a desired area (in the illustrated example, 4
Three straight ground patterns 3-1 shown by dotted lines are provided on the mounting surface of the printed wiring board 1 in order to electromagnetically separate the areas (areas).
3-2 and 3-3 are formed to separate the mounting surface into four desired sections.

A desired number of slit-shaped through holes 2 are arranged in each of the ground patterns 3-L3-2, 3-3. That is, these through-holes are grounded to the frame plate 5 via the ground pattern.

A shield plate 20 made of a thin metal plate is attached to the mounting surface side of the printed wiring board 1 inside the metal case.

The shield plate 20 includes a shield vi 20-1 long enough to be inserted snugly into the frame plate 5 and a shield vi 20-1 divided at right angles to the shield plate 201 in order to divide the mounting surface of the printed wiring board 1 into four desired sections. It is composed of a combination of two shield plates 20-2 and 20-3.

The shield plate 20-1 has a lower edge 23 in contact with a ground pattern 3-1 provided on the mounting surface of the printed wiring board l, and an upper edge 2
2 is in contact with the inner surface of the upper cover 10, and the longitudinal side edge bent at right angles is in contact with the inner wall of the frame board 5, and the main plate member is in the form of an elongated rectangle that partitions the upper part of the printed wiring board l into two parts. 21-1 is the main member.

The shield plate 20-1 has a ground pattern 3-
Leg pieces 25 passing through each of the slit-shaped through holes 2 on the main plate member 21-1 are arranged on the lower edge 23 of the main plate member 21-1. Further, a desired number of protrusions 24 are arranged in one row on the upper edge 22 of the main plate members 21-1.

The lower edge 23 of the shield plate 20-2 is connected to the ground pattern 3.
-2, the upper edge 22 is in contact with the inner surface of the upper cover 10, and one longitudinal side edge bent at right angles is in contact with the frame plate 5.
A short main plate member 21- whose other longitudinal side edge is spot welded to the shield plate 20-1.
2 is the main member.

The shield plate 20-2 has leg pieces 25 that pass through each of the slit-shaped through holes 2 on the ground pattern 3-2.
are arranged on the lower edge 23. Furthermore, the main plate member 21
A desired number of protrusions 24 are arranged in one row on the upper edge 22 of -2.

The shield plate 20-3 is also configured in the same manner as the shield plate 20-2, and is configured such that the lower edge 23 of the main plate member 21-3 comes into contact with the ground pattern 3-3, and the protrusion 24 and the leg piece 2
5 and 5 respectively.

Each shield plate shield plate 2 is attached to the upper cover 10.
Holes 11 are provided in which the projections 24 of the shield plates 20-1.20-2.20-3 are fitted, and the lower cover 15 has holes 11 into which the protrusions 24 of the shield plates 20-1.20-2.20-3 fit. A slit 6 is provided into which the end edge of the leg piece 25 fits.

The shield plate 20 configured as described above is attached to the mounting surface side of the printed wiring board 1 by passing each leg piece 25 through the corresponding slit-shaped through hole 2, and attaching the leg piece 25. The root portion is soldered (or fixed with conductive adhesive) to the slit-shaped through hole 2.

With the shield plate 20 attached to the printed wiring board 1, the printed wiring board 1 is housed and installed in the frame board 5 with the mounting surface facing up, and then the lower cover 15 is attached to the frame board 5 and the slider is inserted. The tip side edge portion of the leg piece 25 that penetrates the eye 6 and projects to the underside of the lower cover 15 is soldered (or fixed with a conductive adhesive) to the lower cover 15. Also, an upper cover 10 is attached to the frame plate 5.
The tip portion of the protrusion 24 that penetrates through the hole 11 and projects above the upper cover IO is soldered (or fixed with a conductive adhesive) to the upper cover 10.

Since it is configured as described above, the shield plate 20-1
．． There is no risk of mutual electromagnetic interference between the circuit components mounted in the compartments partitioned by 20-2 and 20-3.

That is, it becomes possible to mount circuit components that may interfere with each other with high density on a single printed wiring board, promoting miniaturization of electronic devices and reducing costs.

In addition, since the connections between the divided sections are made by patterns on the back side of the printed wiring board or patterns in the inner layer, which are formed at positions avoiding the slit-shaped through holes 2, the connection circuits are short. Speeding up of signals is promoted.

Furthermore, if the leg pieces 25 are arranged in multiple stages with close intervals,
The space on the back side of the printed wiring board 1 can be completely partitioned in terms of electromagnetic waves, and interference between patterns can be prevented.

Note that after the shield plate 20 is accommodated and fixed to the frame plate 5,
The printed wiring board 1 may be inserted into the frame board 5 and the printed wiring board and the leg pieces 25 may be fixed.

By adopting such a mounting order, there is no need to provide the support pieces 6 on the frame plate 5, resulting in lower costs.

〔Effect of the invention〕

As explained above, the present invention provides a shield structure in which a shield plate having leg pieces that penetrate through holes in a printed wiring board is attached to the mounting surface side of the printed wiring board, and circuit components are mounted on the printed wiring board. It has excellent practical effects, such as high-density packaging, miniaturization of electronic devices, low cost, and promotion of higher signal speeds.

[Brief explanation of the drawing]

FIG. 1 is an isolated perspective view of an embodiment of the invention, and FIG. 2 is a cross-sectional view of an embodiment of the invention. In the figure, ■ is a printed wiring board, 2 is a slit-shaped through hole, 3-1, 3-2, 3-3 are ground patterns, 5 is a frame board, 10 is an upper cover 11 is a hole, 15 is a lower cover 16 is Slit, 20.20-1.20-2.20-3 is shield plate, 2
1-1.21-2.21-3 is the main plate member, 22 is the upper edge, 23 is the lower edge, 24 is the protrusion, and 25 is the leg piece. ／＃＼
nJ: Shio Bar

Claims (1)

[Scope of Claims] An electronic device in which a printed wiring board (1) is horizontally housed in a metal case consisting of an upper cover (10), a lower cover (15), and a frame plate (5), the printed wiring board The lower edge (23) that comes into contact with the mounting surface of (1)
, an upper edge (22) that abuts the inner surface of the upper cover (10).
), and a lateral edge abutting the inner wall of the frame plate (5),
A main plate member (21-1, 20-2, 20-3) that partitions the upper part of the mounting surface of the printed wiring board (1) as desired, and slit-shaped through holes ( A shield plate (20) having a leg piece (25) disposed on the lower edge (23) so as to penetrate through the printed wiring board (1), The leg piece (25) is attached to the slit-shaped through hole (2), the tip side edge of the leg piece (25) is attached to the lower cover (15), and the upper edge (22) is attached to the lower cover (15).
A shield structure for a printed wiring board, characterized in that the upper cover (10) is fixed to the upper cover (10) by soldering or with a conductive adhesive.