JPH0452640B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a printed board having a shield cover with a heat dissipation mechanism for the printed board.

Printed boards on which digital signal circuits and the like are formed are generally equipped with a shield cover on the pattern-forming surface in order to prevent electromagnetic waves from entering from the outside and to prevent electromagnetic interference with other printed boards.

Furthermore, as electronic devices become smaller, components are mounted on printed boards at a higher density to reduce the number of printed boards. Therefore, among the mounted components, it is necessary to install a special heat dissipation mechanism for heat generating components that generate a particularly large amount of heat (for example, power transistors, etc.) in order to maintain the characteristics of the heat generating components and other mounted components. It is.

When equipped with such a heat dissipation mechanism for heat generating parts,
This heat dissipation mechanism is required not to impede high-density mounting of components.

[Conventional technology]

FIG. 4 is a partially cutaway side view of a conventional printed board equipped with a heat dissipation mechanism.

In FIG. 4, the shield cover 5 is made of a metal plate (for example, a thin steel plate), and has a shallow box shape whose planar shape is approximately the same as the shape of the printed board 1.

The shield cover 5 is fixed to the printed board 1 with setscrews 6 at its four corners so that the four peripheral frame surfaces are in close contact with the edges of the pattern-formed surface 1B of the printed board 1, and shields the pattern-formed surface 1B. are doing.

Furthermore, a heat generating component 2 is mounted on the component mounting surface 1A of the printed board 1. The heat generating component 2 is in close contact with the component mounting surface 1A via a heat dissipating sheet 4A whose bottom surface is made of a metal plate (for example, aluminum),
It is fixed to the printed board 1 with fixing screws 3.

The heat dissipation sheet 4A is stretched toward one end surface of the heat generating component 2, and heat dissipating pieces 4 are formed in parallel to the main body of the heat generating component 2.

Therefore, most of the heat of the heat generating component 2 is transmitted to the heat radiating piece 4 through the heat radiating sheet 4A, and is radiated from the portion of the heat radiating piece 4 having a large heat radiating area.

[Problem that the invention seeks to solve]

However, the conventional heat dissipation mechanism described above has a problem in that high-density mounting of components is inhibited because a heat dissipation piece with a large heat dissipation area is provided on the component mounting surface.

[Means for solving problems]

The above problem can be solved by the present invention, in which a heat generating component is attached to the component mounting surface on the front surface of the printed board, a shield cover is attached to cover it to the pattern forming surface on the back side, and the shield cover is made of a metal plate and has a planar shape. has a shallow box shape approximately equal to the shape of the printed board, and its edge frame surface is fixed to the edge of the pattern forming surface of the printed board, the shield cover portion corresponding to the component mounting surface of the printed board is a recessed part, A heat dissipation mechanism characterized in that the bottom plate of the recess is closely attached to the pattern forming surface of the printed board through an insulating sheet, and the heat generating component and the bottom plate of the recess of the shield cover are fixed with metal fixing screws through the printed board. The problem is solved by a printed circuit board with a shield cover.

[Effect]

According to the above means of the present invention, the bottom plate portion of the concave portion of the shield cover is brought into close contact with the pattern forming surface of the printed board corresponding to the position where the heat generating component is mounted, and the heat of the heat generating component is transmitted through the bottom plate portion, and almost The heat is transmitted and radiated to the shield cover, which has a large heat radiation area equivalent to that of a printed circuit board. Therefore, there is no need to mount a special heat dissipation piece or the like on the component mounting surface side, and components can be mounted at high density.

〔Example〕

The gist of the present invention will be specifically explained below with reference to illustrated examples. Note that the same reference numerals indicate the same objects throughout the figures.

FIG. 1 is a partially cutaway side view of one embodiment of the present invention, FIG. 2 is a top view of the main part, and FIG. 3 is a back plan view of the main part.

1 to 3, heat generating components 2 are mounted in parallel (three in the illustrated example) on a component mounting surface 1A of a printed board 1, and a shield cover 10 is attached to a pattern forming surface 1B. .

The shield cover 10 is made of a metal plate (for example, a thin steel plate, an aluminum plate, etc.), and has a shallow box shape whose planar shape is approximately the same as the shape of the printed board 1.

This shield cover 10 has at least four corners fixed to the printed board 1 with set screws 6 so that the four peripheral frame surfaces are in close contact with the edges of the pattern forming surface 1B of the printed board 1, and the pattern forming surface 1B
is shielded. In addition, parallel heat generating parts 2
A portion corresponding to 1 is recessed toward the pattern forming surface by drawing or the like, and a recess 11 is provided.

The size of the bottom plate portion 12 of the recess 11 is approximately equal to the area occupied by the heat generating components 2 on the component mounting surface 1A where the heat generating components 2 are arranged in parallel. An insulating sheet (for example, a mica sheet) 7 is inserted between the bottom plate part 12 and the pattern forming surface 1B, and the heat generating component 2 is attached to the printed board 1.
The bottom plate part 12 is brought into close contact with the pattern forming surface 1B by fixing screws 3 attached to the bottom plate part 12.

In this way, the insulating sheet 7 is inserted between the bottom plate part 12 and the pattern forming surface 1B, so that the pattern formed on the pattern forming surface 1B is not short-circuited by the bottom plate part 12.

Since the present invention is configured as described above,
The heat of the heat-generating component 2 is transmitted and radiated via the bottom plate portion 12 of the recess 11 to the shield cover 10, which has a large heat radiating area approximately equal to that of the printed board 1.
Therefore, there is no need to mount a special heat sink or the like on the component mounting surface 1A, and components can be mounted at high density.

In addition, since the shield cover 10 also serves as a heat dissipation mechanism, there is no need for any other heat dissipation mechanism.
Low cost.

〔Effect of the invention〕

As explained above, the present invention has a shield cover equipped with a heat dissipation mechanism, and there is no need to mount a special heat dissipation piece on the component mounting surface of the printed board, and components can be mounted at high density. is possible,
In addition, it has excellent practical effects such as low cost.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway side view of one embodiment of the present invention;
FIG. 2 is a front surface plan view of the main part, FIG. 3 is a back plan view of the main part, and FIG. 4 is a partially cutaway side view of a conventional printed board equipped with a heat dissipation mechanism. In the figure, 1 is a printed board, 1A is a component mounting surface, 1B is a pattern forming surface, 2 is a heat generating component, 3 is a fixing screw, 4 is a heat sink, 5 and 10 are shield covers, 6 is a set screw, and 7 is insulation 11 indicates a recessed portion, and 12 indicates a bottom plate portion.

Claims (1)

[Claims] 1 Heat-generating components are attached to the component mounting surface on the front of the printed board, and a shield cover is attached to the pattern forming surface on the back to cover it.The shield cover is made of a metal plate and has a planar shape that roughly matches the shape of the printed board. In a configuration in which the edge frame surface is fixed to the edge of the pattern forming surface of the printed board in an equally shallow box shape, the shield cover part corresponding to the component mounting surface of the printed board is a recessed part, and the bottom plate part of the recessed part is covered with an insulating sheet. A printed board having a shield cover with a heat dissipation mechanism, which is closely attached to the pattern forming surface of the printed board through the printed board, and is fixed to the heat generating component and the concave bottom plate part of the shield cover with metal fixing screws through the printed board. .