JPH0513972A - Heat dissipating mounting structure of heat releasing part - Google Patents

Abstract

PURPOSE:To enable a heat releasing part to be enhanced in heat dissipating efficiency and shielding effect by a method wherein the heat releasing part is mounted on the wiring pattern of a shielding wiring board, a metal-core board is mounted with a heat sink provided with heat dissipating fins and kept at a signal earth level, and a metal front plate is electrically grounded at a frame earth level. CONSTITUTION:A shielding wiring board 2 and a metal front plate 3 attached to the wiring board 2 overlapping its upside are fixed to a circuit board 1 by screwing so as to fill a front gap between the circuit board 1 and an adjacent circuit board. A heat releasing part 6 is mounted on the wiring pattern 2e of the shielding wiring board 2, and a heat sink 9 provided with heat dissipating fins is mounted on the exposed metal-core board 2b where a second insulating layer 2d is removed. Concerning the shielding wiring board 2, the metal-core board 2b is connected to a signal earth level, and the metal front plate 3 is electrically connected to a shelf by contact and grounded at a frame earth level. The heat released from a heat releasing part is conducted to a heat sink which comes into direct contact with a metal core board, whereby a heat releasing part can be enhanced heat dissipating efficiency.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-dissipating mounting structure for heat-generating components, and more particularly to heat dissipation of heat-generating components mounted on a circuit board and improvement of electromagnetic and electrostatic shielding effects.

In a transmission device, the signal frequency is increased due to the increase in the line capacity, and the wavelength of the electromagnetic wave radiated accordingly is shortened, and electromagnetic noise is becoming a problem. One shelf that constitutes the transmission device has a plurality of circuit boards arranged and mounted, and the circuit boards each have a front plate for closing the front gap between the circuit boards and electromagnetically shielding the front end, and further mounted on the circuit board. The heat generating parts are attached to a heat conducting plate equipped with heat dissipation fins for efficient heat dissipation,
The heat radiation fins are radiated from the opening of the front plate.

However, when the front plate is provided with an opening, the electromagnetic shielding effect is lowered, and there is a problem of electrostatic noise received by electrostatic discharge due to human contact with the front plate and the heat radiation fin. There is.

[0004]

2. Description of the Related Art Conventionally, a circuit board 11 is mounted on a shelf 10 as shown in the perspective view of FIG.
As shown in the perspective view of the main part of FIG. 6, the heat-generating component 12 is mounted, and at the front end, the metal front plate 15 and the right-angled L-shaped heat conduction plate 13 indicated by the chain double-dashed line are attached. A package of the heat-generating component 12 and a radiator 14 having a radiator fin are attached to the plate 13, and the radiator 14 is exposed to the outside through an opening (notched hole) formed in the metal front plate 15 to radiate heat.

[0005]

However, according to the above heat dissipation mounting structure, since the front plate is provided with the notch hole, the electromagnetic shielding effect is deteriorated, or the metal front plate and the heat radiator have a human body. However, there was a problem in that they were touched and received electrostatic noise due to electrostatic discharge.

In view of the above problems, it is an object of the present invention to further improve the heat dissipation efficiency of the heat-generating component and to provide a heat-dissipating mounting structure of the heat-generating component capable of surely shielding electromagnetically and electrostatically. ..

[0007]

In order to achieve the above object, in the heat radiation mounting structure of the heat generating component of the present invention, the first and second insulating layers are provided on both surfaces of the metal core substrate, and further the first insulating layer is formed. On a shield wiring board having a wiring pattern for connecting a heat generating component and a through hole group for connecting to a metal core substrate on a mounting surface where the package of the heat generating component contacts, and a second insulating layer of the shield wiring substrate. A metal front plate that is attached to the circuit board at a front end of the circuit board so as to close a front gap between the circuit board and an adjacent circuit board, and the wiring pattern of the shield wiring board has a heat generating component mounted thereon. The exposed metal core substrate after removing the insulating layer is mounted with a radiator having a radiation fin, and is configured so as to be grounded to a signal ground level and the metal front plate to a frame ground level.

[0008]

[Function] A shield wiring board having a metal front plate stacked thereon is fixed to the front end portion of the circuit board, heat-generating components are mounted on the wiring pattern of the shield wiring board, and a metal core board is mounted on the mounting surface with which the package contacts. By installing a heat sink to the exposed metal core substrate with a group of through holes to be connected, the heat of the heat-generating component is conducted directly from the metal core substrate to the heat sink through the through hole group. It can dissipate heat efficiently. Further, by connecting the metal core substrate of the shield wiring board to the signal ground level and the metal front plate to the signal ground level for ground conduction to the frame ground level, the shield wiring board is protected from electromagnetic noise emitted from the inside. Electromagnetic noise that intrudes from the outside can be shielded, and the metal front plate that is grounded and connected to the frame ground level can shield external electromagnetic noise and electrostatic noise caused by human body contact. The shield wiring board and metal front plate Since the shield layer is doubly formed by and, the shielding effect can be further improved as compared with the conventional case.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The gist of the present invention will be described in detail below with reference to the embodiments shown in the drawings. As shown in the exploded perspective view of the main part of FIG. 1, the circuit board 1 has a shield wiring board 2 at its front end.
And the metal front plate 3 attached to the upper surface of the shield wiring board 2 are screwed and fixed so as to close the front gap between the adjacent circuit board (not shown).

The shield wiring board 2 and the metal front plate 3
Are provided with notches 2a and 3a both of which are provided on the upper and lower ends of the circuit board 1 for escaping the lever 4 for insertion and withdrawal, and spring clips 5 for vertically overlapping and sandwiching the notched edges are provided.

As shown in the side cross-sectional view of the main part of FIG. 2, the shield wiring board 2 has a first metal core board 2b serving as a base and a first metal board 2b.
A wiring pattern 2e that includes an insulating layer 2c and a second insulating layer 2d, and that mounts the heat-generating component 6 on the first insulating layer 2c, and the heat-generating component 6
The mounting surface on which the package 6a comes in contact is provided with a through hole group 2f connected to the metal core substrate 2b for improving heat conduction. Then, the wiring pattern of the shield wiring board 2
The heat-generating component 6 and the second insulating layer 2d are removed from 2e, and the heat radiator 9 having heat radiation fins is attached to the exposed metal core substrate 2b. Further, as shown in the perspective view of the shield wiring board of FIG. 1 viewed from the back surface of FIG. 3, the light emitting diode 7, the connector 8 and the like are also mounted.

The metal front plate 3 is provided with display holes 3b corresponding to the light emitting diodes 7 as shown in FIG. 1, and the upper and lower ends of the metal front plate 3 are shown in a perspective view of the metal front plate of FIG. Attach a contact spring 3c for frame earthing (a shelf (not shown in the drawing, where circuit boards are arranged and housed, is at the grounding level together with the device housing)) and a shield frame 3d surrounding the radiator 9 in FIG. , The shield frame 3d comes out vertically
Equipped with.

The shield wiring board 2 is a metal core substrate.
Connect 2b to the signal ground level via connector 8,
The metal front plate 3 is grounded to the frame ground level by being brought into contact with a shelf (not shown) through a contact spring 3c so as to be conductive.

With this structure, the heat of the heat-generating component is efficiently conducted to the heat dissipating body which is in direct contact with the metal core substrate through the through hole group, so that the heat dissipating efficiency can be improved more than ever. .. Also, since the shield wiring board is conductively connected to the signal ground level, it is possible to shield electromagnetic noise radiated from the inside and electromagnetic noise entering from the outside, and the metal front plate is grounded and conducted to the frame ground level. It is possible to shield external electromagnetic noise and electrostatic noise due to human contact, and since the shield layer is doubled by the shield wiring board and the metal front plate, the shielding effect can be further improved.

[0015]

As described above in detail, according to the present invention,
The heat of the heat-generating component can be dissipated more efficiently than ever before, and the electromagnetic noise and the electrostatic noise can be surely shielded, which is extremely useful in the industry.

[Brief description of drawings]

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

FIG. 2 is a side sectional view of a main part of the shield wiring board of FIG.

3 is a perspective view of the shield wiring board of FIG. 1 seen from the back side.

FIG. 4 is a perspective view of the metal front plate of FIG. 1 viewed from the back side.

FIG. 5 is a perspective view according to the related art.

6 is a perspective view of a main part of the circuit board shown in FIG.

[Explanation of symbols]

1 is a circuit board 2f is a through hole group 2 is a shield wiring board 6 is a heat generating component 2b is a metal core board 6a is a package 2c is a first insulating layer 3 is a metal front plate 2d is a second insulating layer 9 is a radiator 2e Wiring pattern

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Shuichi Tobayashi 1015 Kamiodanaka, Nakahara-ku, Kawasaki-shi, Kanagawa Fujitsu Limited

Claims (1)

Claims: 1. A first insulating layer (2) is provided on both sides of a metal core substrate (2b).
c), a wiring pattern (2e) comprising a second insulating layer (2d) and further connecting the heat generating component (6) on the first insulating layer (2c), and a package (6a) of the heat generating component (6) A shield wiring board (2) having a through hole group (2f) connected to the metal core substrate (2b) on the mounting surface which contacts with the second surface of the shield wiring board (2).
A metal front plate (3), which is stacked and attached onto the insulating layer (2d), is fixed to the front end of the circuit board (1) so as to close the front gap with the adjacent circuit board. The wiring pattern (2e) of the plate (2) mounts the heat-generating component (6), the second insulating layer (2d) is removed and the exposed metal core substrate (2b) has the radiator (9) with the radiation fin. The heat dissipating mounting structure for heat-generating components, characterized in that the metal front plate (3) is grounded to the signal ground level and the metal front plate (3) is grounded to the frame ground level.