Electricity: electrical systems and devices – Miscellaneous
Patent
1987-10-06
1989-04-18
Pellinen, A. D.
Electricity: electrical systems and devices
Miscellaneous
174 35R, 174 51, 361395, 361399, 439 64, 439 76, H05K 900
Patent
active
048232351
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a device for providing an earth connection in a metal core printed circuit board and an improved high heat radiation efficiency. In particular, this invention relates to a device for providing an earth connection in a metal core printed circuit board in which a metal core of the printed circuit board is grounded by connection to a conductive shield casing having the metal core printed circuit board incorporated therein, by means of an electrical conductor which, preferably, has elasticity.
2. Description of the Related Art
As the density at which various electronic components are mounted on a printed circuit board increases, the amount of heat radiation therefrom also increases. To solve the problem of increased heat radiation, thus resulting in an increase of the temperature of the electronic components, a printed circuit board having a metal core, which has a high heat radiation efficiency, has been proposed (see e.g., U.S. Pat. No. 4,336,100.) The heat from the electronic components is uniformly distributed and radiated by the metal core.
This kind of metal core printed circuit board, referred to as a metal core PCB hereinafter, can be implemented, for example, in a bipolar signal/unipolar signal transducer module (B/U transducer) having high frequency devices operating at frequencies higher than 100 megahertz.
It is very important for the metal core PCB to be properly grounded, to ensure that the desired electrical characteristics are realized effectively and reliably.
An example of an earth connection of the metal core PCB is disclosed in, for example, Japanese Unexamined Patent Publication (Kokai) No. 57-155799, in which the metal core has an extension which can be directly connected to a frame which, in turn, can be grounded. In this known earth connection construction, however, the earth connection for the earth pattern of the metal core PCB must be established separately from the earth connection for the metal core. Also, the extension of the metal core, which is inserted in a groove formed in a fastening device provided on the frame to establish an electrical connection between the metal core and the grounded frame, may be accidentally bent and thus incorrectly inserted. The result is that a proper connection cannot be established between the core and the frame.
SUMMARY OF THE INVENTION
The primary object of the present invention is, therefore, to provide an earth connection device in a metal core PCB, which is free from the aforementioned drawbacks and which ensures reliable and stable electrical characteristics.
To achieve the above object, according to the present invention, there is provided an earth connection device in a metal core PCB which has a metal core and an earth pattern in a grounded shield casing, comprising at least one conductive connecting member which is soldered to the earth pattern on the printed circuit board and which is brought into surface contact with the metal core and with the casing when the PCB is assembled with the shield casing.
With this arrangement, the earth connection of the earth pattern and the metal core to the casing can be established at one time by means of a common conductive connecting member.
The metal core is usually made of aluminum, and since, generally speaking, it is very difficult to solder aluminum, it is not practical to attempt to connect the conductive connecting member to the metal core by soldering. Accordingly, the present invention ensures that the connection between the conductive connecting member and the metal core is established merely by a surface contact therebetween.
Preferably, the conductive connecting member is elastic or flexible, so that contact between the metal core and the conductive connecting member and between the metal core and the casing is better ensured, due to the elasticity of flexibility of the conductive connecting member.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a partially cut-away, bottom perspective view, of a sh
REFERENCES:
patent: 4336100 (1982-06-01), Passlick
Arai Katsuyuki
Hayashi Hisao
Kojima Yasushi
Sakiura Jun
Suzuki Mitsuaki
Fujitsu Limited
Pellinen A. D.
Thompson Gregory D.
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