LAYERED HEAT SPREADER AND METHOD OF MAKING THE SAME

摘要

A HEAT SPREADER (22) HAVING AT LEAST TWO ADJOINING LAYERS EACH HAVING AT LEAST TWO PYROLYTIC GRAPHITE STRIPS CUT FROM A SHEET (10) OF PYROLYTIC GRAPHITE ALONG THE Z DIRECTION. THERMAL CONDUCTIVITY IN THE XY PLANE OF THE GRAPHITE SHEET (10) IS GREATER THAN IN THE Z DIRECTION. THE Z DIRECTION CUT PROVIDES STRIPS WHICH ARE EACH ORIENTED 90 DEGREES SUCH THAT THE THICKNESS DIRECTION OF THE ORIGINAL SHEET (10) BECOMES THE WIDTH OR LENGTH OF THE CUT STRIP. A SIDE OF A FIRST STRIP ADJOINS A SIDE OF A SECOND STRIP IN EACH LAYER. BECAUSE OF THE GREATER THERMAL CONDUCTIVITY IN THE XY PLANE OF THE STRIPS AS COMPARED TO THE Z DIRECTION HEAT TRANSFERS MORE RAPIDLY IN THE LENGTH AND THICKNESS DIRECTION OF THE STRIPS THAN ACROSS ADJOINING SIDES OF THE ORIENTED STRIPS IN EACH LAYER. THE FIRST LAYER STRIPS ARE ORIENTED ABOUT 90 DEGREES FROM THE ORIENTATION OF THE SECOND LAYER STRIPS.