Composite heat transfer means

A printed circuit board assembly comprising a thermal plane heat transfer member sandwiched between an opposed pair of printed circuit boards upon which heat generating electronic components are adapted to be mounted and wherein the thermal heat transfer member extends beyond at least one peripheral edge of the pair of printed circuit boards, and wherein the thermal plane heat transfer member comprises a generally planar composite member in which elongated conductive graphite fibers are disposed within a matrix material, the composite member having a pair of opposing planar outer surfaces substantially parallel with each other and a central heat flux conducting portion between the pair of planar outer surfaces, the opposed pair of circuit boards being secured to the pair of opposed planar outer surfaces, and wherein the fibers are oriented predominantly in a common direction within the planar composite member, and wherein at least at one end the fibers are inclined at an angle with respect to the plane of the composite member such that the fiber ends terminate at a peripheral thermal contact surface of the composite member, which thermal contact surface is substantially parallel to a surface of the substantially planar composite member, whereby heat flux into the central heat flux conducting portion of the composite member from the heat generating electronic components on the pair of circuit boards is transferable along the commonly directed fibers and is efficiently transferable from the member through fiber ends at the thermal contact surface.

A printed circuit board assembly comprising:

• a composite member formed from elongated, thermally conductive fibers disposed within a matrix material;
• said fibers being oriented predominantly in a common direction to provide said composite member with at least a pair of generally planar outer surfaces which are substantially parallel with each other and a central heat flux conducting portion between said pair of outer surfaces with the fibers in the central heat flux conducting portion extending parallel to the planar outer surfaces,
• said composite member having at least one end portion wherein said fibers are angularly spaced from said planar outer surfaces such that the end portions of said fibers terminate at a generally planar peripheral thermal contact surface;
• at least one printed circuit board having heat-generating electronic components positioned thereon and secured to one of said composite member planar outer surfaces at a location spaced from said end portion;
• and
• said composite member being operable to transfer heat generated by said electronic components and introduced into said composite member central heat flux conducting portion through said commonly directed fibers to said fiber end portions at said thermal contact surface.