JPH06181395A - Heat dissipation printed-wiring board - Google Patents

Abstract

PURPOSE:To contrive economically the improvement of the heat dissipation property of a heat dissipation printed-wiring board without inhibiting the improvement of the mounting density of components and a reduction in the heights of the components. CONSTITUTION:Heating components 2 are mounted and soldered on a printed-wiring board 1. A wire netting 3 covers the whole surface of the board 1 including the mounted heating components 2 and in a state that the wire netting comes into contact to these heating components 2, the wire netting 3 is mounted to the board 1 being formed into a shape that the wire netting is bent at the peripheral edge parts of the board 1 to hold the board between the bent parts and is fixed on the board 2. A method of fixing the wire netting 3 on the board 1 tray be a partial soldering method in addition to a system that the wire netting is bent to hold the board 1 between the bent parts. Accordingly, heat generated from the components 2 is dissipated to the outside being supported by the heat conductivity and air permeabilityof the wire netting 3 via the wire netting 3 to come into contact to these components 2 and a heat dissipation effect is fulfilled. In order to fill up a gap between the wire netting 3 and the components 2 to support heat conduction, a rubber having a heat conductivity may be inserted in the gap and instead of the wire netting, a thin metal plate with small holes opened in its whole surface can be used.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat radiation type printed wiring board which is capable of economically improving heat radiation performance without impeding improvement of mounting density of parts and reduction of height dimension.

[0002]

2. Description of the Related Art In recent years, as the speed and integration of semiconductor devices have increased, the amount of heat generated per component or package has tended to increase. In particular, it is remarkable in a CPU (central processing unit), a PLD (programmable logic device), and the like. Generally, the printed wiring board is
Since a glass cloth base epoxy substrate is used and has a low thermal conductivity, the heat generated from the mounted component is radiated only from the component surface. Therefore, the temperature of the heat-generating component rises anyway, leading to deterioration and lowering the reliability of the device. The forced air cooling method involves structural changes in the entire apparatus, and is therefore difficult to implement due to space limitations. Therefore, it is practical to take measures for heat dissipation on the printed wiring board itself.

As one of the solutions, there is a method of a metal core type printed wiring board. It is more effective to attach a radiation fin (radiator) to this. A conventional example of this metal core type printed wiring board system will be described with reference to FIG. 4 which is a side view of the main part thereof. In FIG. 4, the substrate 21 has a structure in which a metal plate 22 is sandwiched from both sides by insulating layers 23 in a fixed manner. A circuit pattern 24 is formed on the surface of the upper insulating layer 23. Although not shown here, when a through hole is provided, a hollow portion is formed in the metal plate 22 so as to avoid that portion. The heat generating component 26 is mounted and soldered on the circuit pattern 24.
The heat radiation fins 27 are directly screw-attached to the upper surface of the metal plate 22 which is partially exposed. Of course, the insulating layer 23 and the circuit pattern 24 on the upper surface side of the metal plate 22 corresponding to the place where the heat radiation fin 27 is attached are removed. The substrate 21 originally has good heat conductivity due to the metal plate 22, and has excellent heat dissipation. Therefore, the local temperature rise due to the heat generation of the mounted component 26 is suppressed, and it is expected that the service life is extended and the reliability of the entire device is improved. As in this conventional example, the substrate 21
Further, if the radiation fin 27 is attached, it is more effective in terms of heat radiation.

[0004]

The conventional examples of the metal core type printed wiring board system have the following drawbacks. (1)
The board of the metal core type printed wiring board is more expensive than the glass cloth-based epoxy board. (2) The heat dissipation is high, so it is difficult to solder, and it is difficult to replace the parts. (3) The radiator is attached. , It is difficult to attach directly to the heat-generating component or package, and it is necessary to use a package with a special radiator or a package with a radiator attached.
(4) Providing a radiator, which leads to an increase in cost, hinders itself from increasing the mounting density of components, and increases the height dimension of the printed wiring board, which hinders miniaturization.

An object of the present invention is to solve the above problems of the prior art and to improve the heat dissipation and reduce the cost without impeding the improvement of the mounting density of parts and the reduction of the height dimension. The purpose is to provide a printed wiring board.

[0006]

According to a first aspect of the present invention, there is provided a heat radiation type printed wiring board in which a thin plate member having thermal conductivity and air permeability covers the entire surface including a heat generating component mounted and soldered, and In a state of being in contact with the heat generating component, the peripheral part is fixed and attached.

The heat radiation type printed wiring board according to claim 2 is
The printed wiring board according to claim 1, wherein the thermal conductivity,
An insulating member having elasticity is interposed between the thin plate member and the heat generating component. A heat dissipation type printed wiring board according to a third aspect is the printed wiring board according to the first or second aspect, wherein the thin plate-shaped member is a thin metal plate having small holes formed on the entire surface.

A heat dissipation type printed wiring board according to claim 4 is
In the printed wiring board according to claim 1 or 2, the thin plate member is a wire mesh.

[0009]

In the heat dissipation type printed wiring board according to any one of claims 1 to 4, the thin plate-shaped member covers the entire surface including the mounted heat generating component and is in contact with the heat generating component,
Since it is attached to the printed wiring board in such a manner that it is fixed at its peripheral portion, the heat generated from the parts is transferred to the outside through the thin plate-shaped member that comes into contact with the heat generation and the air permeability. Dissipated.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a heat radiation type printed wiring board according to the present invention will be described below with reference to the drawings. FIG. 1 is an exploded perspective view of the embodiment. In the figure, a heat generating component 2 is mounted and soldered on a printed wiring board 1. Here, different types of parts are also commonly denoted by reference numeral 2.
In the state where the wire net 2 covers the entire surface including the mounted heat-generating component 2 and is in contact with the heat-generating component 2, the printed wiring board 1 is
It is attached in such a shape that it is bent at its peripheral portion and sandwiched and fixed. The method of fixing the wire net 3 to the printed wiring board 1 may be partial soldering, in addition to the method of bending and sandwiching. Therefore, the heat generated from the component 2 is dissipated to the outside through the metal net 3 which is in contact with the component 2 and is supported by the heat conductivity and the air permeability, and the heat radiation effect is exhibited.

The contact state between the wire net 3 and the component 2 will be described in more detail with reference to FIG. In the figure,
Since the parts 2a and 2b have different heights, in order to compensate for the difference, the insert parts 4 made of rubber having thermal conductivity are used.
a and 4b are inserted between the wire mesh 3 and the wire mesh 3. Each insert 4
Due to the elasticity of a and 4b, the parts 2a and 2b are firmly fixed to the wire net 3 without any gaps, and also due to their thermal conductivity, the parts 2a and 2b are fixed to the wire net 3
It is assisted to be dissipated through.

FIG. 3 is a side view of the essential part partially modified in the embodiment. The modified point of this embodiment is that the insertion parts are not provided for all the parts between the wire mesh and the parts, but the insertion parts are not provided for some parts and the parts are directly contacted with the wire mesh. . In the figure, the component 2a is provided with an insertion component 4c, but the component 2b is brought into direct contact with the wire mesh 3. Generally, each component is classified into two or three stages according to height, and the configuration can be simplified depending on whether one or two types of insertion components are provided or not. At this time, the partial deformability due to the elasticity of the wire net 3 works effectively. In the extreme case, it is also possible to rely entirely on the partial deformation of the wire mesh 3 and not to use any inserts. Note that, instead of the wire mesh, a thin metal plate having small holes on its entire surface can be used. The metal plate with small holes is
Although the contact area with parts is large and the wire mesh is superior in terms of heat transfer, it is slightly inferior to the wire mesh in terms of partial deformation, so it is necessary to use it properly according to the placement and height of the mounted parts on the printed wiring board. .

[0013]

In the heat dissipation type printed wiring board according to the present invention, the thin plate-shaped member covers the entire surface including the mounted heat generating component,
Moreover, since it is attached to the printed wiring board while being in contact with the heat-generating component in such a manner that it is fixed at its peripheral edge, the heat generated from the component is transferred to the heat-conductive component through the thin plate-shaped member in contact therewith. Since it is diffused to the outside by being supported by the air permeability and the air permeability, it is possible to improve the heat dissipation and reduce the cost without hindering the improvement of the mounting density of components and the reduction of the height dimension.

Particularly, in the heat radiation type printed wiring board according to the second aspect, the insulating member interposed between the thin plate member and the heat generating component assists the dissipation of heat from the component and the component holding, and Since the variation in the height dimension of the component is corrected, the flexibility in applying the mounted component is increased. Particularly, in the heat dissipation type printed wiring board according to claim 3 or 4,
Since the thin plate-shaped member is a metal thin plate or a wire mesh in which small holes are formed on the entire surface, manufacturing is facilitated and cost reduction is supported.

[Brief description of drawings]

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

FIG. 2 is a side view of a main part of the embodiment.

FIG. 3 is a side view of an essential part partially modified in the embodiment.

FIG. 4 is a side view of a main part of a conventional example.

[Explanation of symbols]

 1 Printed wiring board 2a, 2b Parts 3 Wire mesh 4a, 4b, 4c Inserted parts

Claims (4)

[Claims] 1. A thin plate member having thermal conductivity and air permeability,
Covers the entire surface, including heat-generating components mounted and soldered,
A heat radiation type printed wiring board, characterized in that the heat radiation type printed wiring board is mounted so as to be fixed at the peripheral edge while being in contact with the heat generating component. 2. The printed wiring board according to claim 1, wherein an insulating member having thermal conductivity and elasticity is interposed between the thin plate member and the heat generating component. 3. The printed wiring board according to claim 1, wherein the thin plate member is a thin metal plate having small holes formed on the entire surface thereof. 4. The heat dissipation type printed wiring board according to claim 1 or 2, wherein the thin plate member is a wire mesh.