JP4899460B2 - Heat transfer body and electronic equipment using it - Google Patents

Description

  The present invention relates to a heat transfer body and an electronic device using the same.

  For example, even in portable electronic devices such as personal computers and mobile phones, semiconductor integrated circuits (CPUs) and power amplifiers provided inside them become heat-generating components, and suppressing the heat generation improves the performance as electronic devices. It is necessary above.

In view of the above situation, in recent electronic devices, a heat radiator is brought into contact with the heat generating component via the graphite sheet, and the heat of the heat generating component is radiated to the heat radiator via the graphite sheet, and the temperature rise is increased. There is something to be suppressed (for example, Patent Document 1 below).
JP 2005-311079 A

  In the above conventional example, the heat of the heat generating component is surely transferred to the radiator through the graphite sheet, and as a result, the temperature rise of the heat generating component is greatly suppressed, and the performance is not deteriorated. .

  In such a conventional example, the graphite sheet is obtained by forming expanded graphite into a sheet, that is, graphite produced by a so-called expanding method, in which graphite powder obtained by heating natural graphite after acid treatment is formed into a sheet shape. Although it is a sheet, since such an expanded graphite sheet is brittle, its upper and lower surfaces are covered with a heat transfer material such as an aluminum sheet.

  The expanded graphite sheet having such a structure has a high heat transfer effect as it is, but in order to further enhance the heat transfer effect, the wall thickness must be further increased.

  However, since portable electronic devices such as the above personal computers and mobile phones are required to be smaller and lighter, it is necessary to further increase the thickness of the expanded graphite sheet to increase its heat transfer effect. It is impossible to increase the heat transfer effect without increasing the wall thickness.

  Therefore, the object of the present invention is to further enhance the heat transfer effect without increasing the wall thickness so much.

  In order to achieve this object, the heat transfer body of the present invention includes an expanded graphite sheet, a U-shaped pyrolytic graphite sheet enclosing at least a part of each of the upper and lower surfaces of the expanded graphite sheet, and the expanded graphite. The intended purpose is achieved by wrapping the upper and lower surfaces of the polymer of the sheet and the pyrolytic graphite sheet.

  As described above, the present invention is a U-shaped pyrolytic graphite sheet that is thinner than the expanded graphite sheet and has a much higher heat transfer effect per unit volume. Since at least a part of each of the upper and lower surfaces of the graphite sheet is wrapped, the heat transfer effect can be further enhanced without increasing the thickness of the heat transfer body so much.

  Further, since the pyrolytic graphite sheet has a U-shape, and the U-shaped pyrolytic graphite sheet wraps at least part of the upper and lower surfaces of the expanded graphite sheet, the pyrolytic graphite sheet is expanded graphite. It can be easily and easily mounted on the upper and lower surfaces of the seat.

  Hereinafter, a heat transfer body of the present invention and an electronic device using the heat transfer body will be described with reference to an embodiment and drawings. The pyrolytic graphite sheet means a highly oriented graphite sheet obtained by treating a polymer film such as polyimide at a high temperature in a neutral or reducing atmosphere.

  FIG. 1 shows a portable personal computer, 1 is a display, 2 is a keyboard, and 3 is a main body.

  A circuit board 4 shown in FIG. 2 is provided inside the main body 3, and an outlet 5 is mounted on the circuit board 4, and a control device 6 is attached to the outlet 5.

  As is well known, the control device 6 has a built-in CPU and the like, and in recent years, the processing speed has been dramatically increased, so that heat generation is also increased. Therefore, in this embodiment, this control device 6 will be described as a heating element.

  The top surface of the control device 6 is in contact with the lower surface of the heat transfer body 7 shown in FIGS. 2 and 3, and on the upper surface of the heat transfer body 7, a heat radiating plate 8 formed of aluminum as a heat radiating member is applied. It is touched. Further, the heat radiating plate 8 is extended to an appropriate place in the main body 3 shown in FIG. 1, whereby final heat radiation is performed.

  Here, the heat transfer body 7 shown in FIGS. 2 and 3 will be described.

  The heat transfer body 7 includes a rectangular expanded graphite sheet 9 shown in FIG. 4, a partially U-shaped pyrolytic graphite sheet 10 wrapping at least a part of each of the upper and lower surfaces of the expanded graphite sheet 9, and The expanded graphite sheet 9 and a heat transfer sheet 11 used as an example of a heat transfer material enclosing the upper and lower surfaces of the polymer of the pyrolytic graphite sheet 10 are constituted.

  As shown in FIG. 4, the inner heat transfer sheet 11 is composed of two upper and lower heat transfer sheets 11a and 11b. The inner and lower heat transfer sheets 11b are wider than the upper heat transfer sheet 11a. In the case where the expanded graphite sheet 9 is extruded in a longitudinal trapezoidal shape downward and in an inverted trapezoidal shape to wrap the upper and lower surfaces of the polymer of the pyrolytic graphite sheet 10, the upper heat transfer sheet 11a is in a flat state, After the outer periphery of the transfer sheet 11b is bent from the outer periphery of the expanded graphite sheet to the upper heat transfer sheet 11a, the outer peripheral surfaces of the upper and lower heat transfer sheets 11a and 11b are polymerized and bonded together, thereby expanding. The upper and lower surfaces of the polymer of the graphite sheet 9 and the pyrolytic graphite sheet 10 are structured to be wrapped by these two upper and lower heat transfer sheets 11a and 11b.

  And the heat transfer body 7 formed in this way pushes the central part in the longitudinal direction downward in an inverted trapezoidal shape, and presses the pushed part against the top surface of the control device 6 as shown in FIG.

  Now, the lower surface side of the expanded graphite sheet 9 corresponding to the extruded portion 7A is covered with the pyrolytic graphite sheet 10 in a reverse trapezoidal shape downward in the longitudinal center of the heat transfer body 7 as described above. .

  The pyrolytic graphite sheet 10 is partially U-shaped as described above, and the upper surface side of the pyrolytic graphite sheet 10 covers the upper surface side of the expanded graphite sheet 9 widely.

  Specifically, as shown in FIG. 5, if the square pyrolytic graphite sheet is cut into an L-shape, two pyrolytic graphite sheets 10 can be formed. For example, the U-shaped pyrolytic graphite sheet 10 shown in FIG. 4 can be formed.

  In the above state, the heat generated by the control device 6 is transmitted to the heat transfer body 7, where it is widely spread outward, and then extended to an appropriate place in the main body 3 via the heat radiating plate 8. Thereby, final heat dissipation is performed.

  Here, on the lower surface side of the expanded graphite sheet 9 corresponding to the extruded portion 7A, that is, the portion pressed against the top surface of the control device 6 in the inverted trapezoidal shape downward in the longitudinal center portion of the heat transfer body 7, As shown in the figure, it is covered with the pyrolytic graphite sheet 10.

  Since the pyrolytic graphite sheet 10 is thinner than the expanded graphite sheet 9 and has a much higher heat transfer effect per unit volume, the heat of the top surface portion of the control device 6 is effectively transferred outward. Heat can be transferred, and the pyrolytic graphite sheet 10 is U-shaped and covers the upper surface of the expanded graphite sheet 9, so that the heat of the top surface of the control device 6 is also effective from this point. Therefore, heat can be transferred outward, and as a result, the heat transfer effect can be further enhanced without increasing the thickness of the heat transfer body 7 so much.

  In addition, since the U-shaped pyrolytic graphite sheet 10 wraps at least part of the upper and lower surfaces of the expanded graphite sheet 9, the pyrolytic graphite sheet 10 is placed on the upper and lower surfaces of the expanded graphite sheet 9, It can be easily installed with good workability.

  In the above embodiment, the pyrolytic graphite sheet 10 is L-shaped as shown in FIG. 5 and the amount of the pyrolytic graphite sheet 10 used is reduced. The heat transfer effect may be further enhanced by covering.

  As described above, according to the present invention, the temperature rise of the heat-generating component is greatly suppressed, and substantial performance deterioration does not occur. Therefore, the present invention is extremely useful in various electronic devices.

The perspective view of one Embodiment of this invention The principal part enlarged front view of one Embodiment of this invention The principal part expansion perspective view of one Embodiment of this invention The principal part disassembled perspective view of one Embodiment of this invention The principal part enlarged plan view which shows the manufacturing method of one Embodiment of this invention

Explanation of symbols

6 Control device (heat generating parts)
7 Heat transfer body 8 Heat sink 9 Expanded graphite sheet 10 Pyrolytic graphite sheet

Claims (3)

An expanded graphite sheet, a U-shaped pyrolytic graphite sheet enclosing at least a part of each of the upper and lower surfaces of the expanded graphite sheet, and heat enveloping the upper and lower surfaces of a polymer of the expanded graphite sheet and the pyrolytic graphite sheet A heat transfer body provided with a transfer material , wherein the heat transfer body on the lower surface side of the expanded graphite sheet is brought into contact with a heat generating body, and the upper surface side of the expanded graphite sheet of the pyrolytic graphite sheet A heat transfer body characterized in that the area is larger than the area on the lower surface side of the expanded graphite sheet . The heat transfer body according to claim 1, wherein the pyrolytic graphite sheet is obtained by bending an L-shaped piece. An electronic apparatus comprising the heat transfer body according to claim 1, wherein an upper surface of the heat transfer body is brought into contact with a heat radiating body.

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