JP2007149855A - Electronic device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electronic device which has a simple and space-saving structure to efficiently cool a heater. <P>SOLUTION: The electronic device comprises a circuit board (main board 15), the heater (IC board 16) mounted on the circuit board; a heat receiving member 33 thermally connected to the heater; a heat dissipating means (heat exchanger 18) which dissipates heat from the heat receiving member 33; a heat transfer means (heat pipe 35) of which one end and the other end are connected thermally to the heat receiving member and the heat dissipating means, respectively, and which transfers heat from the heat receiving member to the heat dissipating means; and a press means (press spring 37) which presses the part of heat receiving means that is other than the part to which the heat transfer means is connected, toward the heater to press the heat receiving means to the heater. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a heat receiving member for cooling a heating element such as an IC board mounted on a circuit board and an electronic device such as a personal computer provided with a heat radiating means. More specifically, the heating element is cooled by a simple and space-saving structure. It relates to an electronic device that has been made possible.

  As disclosed in Patent Document 1 and Patent Document 2, as a general cooling structure example for cooling a heating element such as an IC substrate mounted on a circuit board, a good heat conducting material such as aluminum is used on the heating element. The heat receiving member is placed, and the heat receiving member and the heat exchanger are connected by a heat pipe, and the heat receiving member is pressed onto the heating element by a spring-like pressing member to heat the heat receiving member to the heating element. It is known that the heat of the heat generating element is transferred to the heat exchanger side by connecting the heat generating elements.

  In the cooling structure of Patent Document 1, a heat pipe is disposed in the center of the heat receiving member placed on the heating element, and is formed in a four-leg shape so as to cover the heating element, the heat receiving part, and the heat pipe. The heat receiving member is pressed against the heat generating body together with the heat pipe by the central portion of the leaf spring-shaped pressing member, and thereby the heat receiving member is pressed against the heat generating element.

Further, in the cooling structure of Patent Document 2, the four corners of the heat receiving member placed on the heating element are pressed toward the heating element by a coil spring-like pressing member, and the heat receiving member is pressed against the heating element.
JP 2003-101269 A JP 2003-258472 A

  However, in the cooling structure of Patent Document 1, since the heating element, the heat receiving member, the heat pipe, and the pressing member are all overlapped in the height direction, a large space is required. It was difficult to apply.

  Moreover, in order to prevent the heat pipe formed of a relatively soft material from being directly pressed by the pressing member and deformed, it is necessary to interpose a protective plate between the heat pipe and the pressing member. It was forced to become.

  Further, in the cooling structure of Patent Document 2, the number of parts increases and the structure becomes complicated. At the same time, when the pressing forces of the four pressing members are not uniform, the heat receiving member may be inclined with respect to the heating element. In this case, there is a concern that the heating element and the heat receiving member cannot be in close contact with each other, and the cooling efficiency is greatly reduced.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an electronic device that can efficiently cool a heating element with a simple and space-saving structure.

  In order to achieve the above object, an electronic device according to the present invention includes a circuit board, a heating element mounted on the circuit board, a heat receiving member thermally connected to the heating element, and heat of the heat receiving member. A heat dissipating means for dissipating heat, a heat transfer means for thermally transferring one end to the heat receiving member and the other end to the heat dissipating means, respectively, and transferring heat of the heat receiving member to the heat dissipating means; and Pressing means for pressing the heat receiving member against the heating element by pressing a part other than the part to which the heat transfer means is connected to the heating element side.

  According to the electronic device of the present invention, the heating element can be cooled with good cooling efficiency by a simple and space-saving structure.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a perspective view of a notebook personal computer showing an example of an electronic apparatus to which an embodiment of the present invention is applied. In the personal computer 1, a display unit 3 is connected to a main body 2 via a hinge unit 4 so as to be opened and closed. A keyboard 5 and a touch pad 6 are provided on the upper surface of the main body 2. A liquid crystal display panel (LCD) 7 is provided inside the display unit 3.

  The main body 2 has a main body housing 9 made of resin, and the display unit 3 has a display unit housing 10 made of resin. The display housing 10 has an exposure opening 11 for exposing the built-in liquid crystal display panel 7.

  A main board 15 (circuit board) is built in the main body housing 9, and an IC board 16 (heating element) is mounted on the main board 15 on the left side, for example, as shown in FIGS. Has been. A heat exchanger 18 (heat dissipating means) is installed behind the IC substrate 16, and a fan unit 19 is installed adjacent to the inside of the heat exchanger 18.

  The fan unit 19 includes a fan 23 that is rotationally driven by an electric motor 22 inside a fan case 21, and air inlets 24 are opened on the upper and lower surfaces of the fan case 21. On the other hand, the heat exchanger 18 includes a fin cover 27 that is continuous with the ejection opening 25 on the left side surface of the fan case 21, and a plurality of radiating fins 28 are arranged in parallel with each other at a predetermined interval. The surface direction of each radiating fin 28 is along the ejection direction (arrow A) of the fan unit 19, and the outlet opening 29 of the fin cover is provided on the left side surface of the main body housing 9 (see FIG. 1). Facing inside.

[First Embodiment]
The IC substrate 16 serving as a heat generating portion is substantially square and is mounted on the upper surface of the main substrate 15 and electrically connected thereto. A small square heat conducting portion 32 is provided on the upper surface. On the upper surface of the heat conducting portion 32, a heat receiving member 33 formed in a short plate shape by a good heat conducting material such as aluminum is placed. The outer peripheral dimension of the heat receiving member 33 is slightly larger than that of the IC substrate 16, and the lower surface of the heat receiving member 33 and the upper surface of the heat conducting portion 32 are in surface contact with each other.

  For example, one end of two heat pipes 35 (heat transfer means) is placed near the left and right ends of the upper surface of the heat receiving member 33 so as to overlap the heat receiving member 33 in plan view (see FIG. 3). They are joined and thermally connected by joining means such as adhesion and fitting. The other end of the heat pipe 35 extends to the heat exchanger 18 side, passes through the fin cover 27 and the heat radiation fin 28 of the heat exchanger 18, and is thermally connected to each heat radiation fin 28. The heat pipe 35 has a known structure in which a coolant such as water or chlorofluorocarbon is enclosed with air inside a metal tube such as an aluminum tube or a brass tube whose ends are closed.

  On the other hand, a pressing spring 37 (pressing means) is provided between the heat receiving member 33 in a plan view, where the heat pipe 35 does not overlap, for example, between the two heat pipes 35. The pressing spring 37 is installed so as to straddle the heat receiving member 33 from above, and the heat receiving member 33 is pressed against the IC substrate 16 by the urging force of the pressing spring 37, so that the space between the heat conducting portion 32 and the heat receiving member 33 of the IC substrate 16 is increased. The surface contact pressure increases, and both members 32 and 33 are thermally connected well.

  The pressing spring 37 is formed in a plate spring shape having a constant width, for example, and the longitudinal direction thereof is parallel to the longitudinal direction of the heat pipe 35. As shown in FIGS. 2 and 4, the pressing spring 37 is bent so that the central portion has a substantially trapezoidal shape, fastening pieces 39 are formed at both front and rear ends thereof, and the intermediate portion is the pressing portion 40. A pressing protrusion 41 that protrudes downward is formed on the pressing portion 40.

  The fastening piece 39 of the pressing spring 37 is fastened and fixed on the main substrate 15 with a screw 42 or the like, the pressing projection 41 abuts on the center of the upper surface of the heat receiving member 33, and the heat receiving member 33 is moved to the IC substrate 16 by the urging force of the pressing spring 37. It is pressed against the heat conducting part 32.

  In the personal computer 1 configured as described above, the heat generated when the IC board 16 is operated is received by the heat receiving member 33 through the heat conducting portion 32 and further transferred to the heat exchanger 18 by the two heat pipes 35. Is done. When the electric motor 22 of the fan unit 19 is activated and the fan 23 rotates, the air inside the main body housing 9 is sucked from the air inlet 24 of the fan case 21, and the sucked air is discharged from the ejection opening 25 of the fan case 21. It flows into the fin cover 27 of the heat exchanger 18, passes through between the numerous heat radiation fins 28, and is discharged to the outside through the outlet opening 29 and the heat exhaust port 30 of the main body housing 9. At that time, the heat of the IC substrate 16 transferred to each of the heat radiation fins 28 is taken away and discharged from the heat exhaust port 30, and the heat of the IC substrate 16 is radiated from the heat exchanger 18.

  In the present embodiment, two heat pipes 35 are connected (fixed) near both sides of the upper surface of the heat receiving member 33, and the upper surface of the heat receiving member 33 other than the portion to which the heat pipe 35 is connected, for example, two heat pipes A pressing spring 37 formed in the shape of a leaf spring having a constant width is disposed in parallel with the heat pipe 35 at the center of the upper surface of the heat receiving member 33 between the pressing protrusions 41 provided at the center of the pressing spring 37. Thus, the heat receiving member 33 is pressed to the IC substrate 16 side to receive heat. For this reason, the heat pipe 35 and the pressing spring 37 are not stacked in the height direction, and both the members 35 and 37 overlap in a side view (see FIG. 4). The heat receiving member 33, the heat pipe 35, and the pressing spring 37 can be easily installed even when the casing main body 9 is thin.

  In addition, since the heat pipe 35 made of a relatively soft material is not directly pressed by the pressing spring 37, it is not necessary to install a protective plate or the like for preventing the deformation of the heat pipe 35 that has been necessary in the past. Thus, the structure can be simplified.

  Since only the central portion of the heat receiving member 33 is pressed by the pressing spring 37 (pressing protrusion 41), the heat receiving member 33 can be brought into surface contact with the heat conducting portion 32 of the IC substrate 16 without being inclined relatively, and the heat of the IC substrate 16 can be efficiently transferred. It can receive heat and has high cooling efficiency. As described above, the heating element such as the IC substrate 16 can be efficiently cooled by the simple and space-saving structure.

[Second Embodiment]
FIG. 6 shows a second embodiment of the present invention. In this figure, the configuration of the main board 15, the IC board 16, the heat conducting section 32, the heat pipe 35, and the pressing spring 37 is the same as that of the first embodiment shown in FIG. .

  The heat receiving member 45 has a bent vertical cross-sectional shape, and stepped portions 46 are formed on both sides of the upper surface so as to enter the IC substrate 16 side (downward here). And the heat pipe 35 is mounted on the upper surface of this level | step-difference part 46, and it joins and is thermally connected.

  The pressing spring 37 is installed across the heat receiving member 45 in the same manner as in the first embodiment, and is arranged in parallel between the two heat pipes 35 in a plan view (see arrow B in FIG. 6). The pressing protrusion 41 presses the center of the upper surface of the heat receiving member 45 to press the heat receiving member 45 against the IC substrate 16 (heat conducting portion 32). The operation of each part is the same as in the first embodiment.

  In this configuration, since the heat pipe 35 is placed on the stepped portion 46 formed on the heat receiving member 33, the heat receiving member 45, the heat pipe 35, the pressing spring 37, and the heat receiving member 45 are viewed in the surface direction (see arrow C in FIG. 6). Are overlapping. As a result, the height from the main board 15 to the upper surface of the heat pipe 35 can be further reduced to greatly contribute to the thinning of the casing body 9.

  Further, since the heat pipe 35 is in contact with the heat receiving member 45 on its two lower and inner surfaces, the heat of the heat receiving member 45 can be efficiently transferred to the heat pipe 35. The step 46 is formed on the lower surface side of the heat receiving member 45 and the heat pipe 35 is fixed to the heat receiving member 45 from below, or the step 46 is formed in a groove shape so that the heat pipe 35 is formed on the lower surface and both side surfaces. The heat receiving member 45 may be brought into contact with the surface.

[Third Embodiment]
FIG. 7 shows a third embodiment of the present invention. In this figure, the configurations of the main board 15, the IC board 16, the heat conducting section 32, and the heat receiving member 33 are the same as those in the first embodiment shown in FIG.

  Here, one heat pipe 49 is provided at the center of the upper surface of the heat receiving member 33, and two pressing springs 50 are provided on both sides thereof. The shapes and actions of the heat pipe 49 and the pressing spring 50 are the same as those in the first embodiment and the second embodiment.

  If the two pressing springs 50 are provided in this manner, the heat receiving member 33 can be pressed against the IC substrate 16 (heat conducting portion 32) with a stronger pressing force, thereby improving the cooling efficiency. Further, it is possible to improve the vibration resistance by preventing the heat receiving member 33 from being displaced with respect to the IC substrate 16. Two or more heat pipes 49 may be arranged, or a plurality (or a single) heat pipe 49 and a plurality (or a single) pressing spring 50 may be alternately arranged. In short, the heat pipe 49 and the pressing spring 50 may not be stacked in the thickness direction (height direction).

  By the way, the present invention can be widely applied not only to a notebook personal computer but also to any other electronic device such as a desktop personal computer, a word processor, an audio device, a video device, and a communication device.

FIG. 11 is a perspective view of a notebook personal computer showing an example of an electronic apparatus according to the invention. The perspective view which shows the principal part of this invention. The top view which shows the principal part of this invention. The side view by the IV arrow of FIG. The front view which shows 1st Embodiment of this invention by the V arrow view of FIG. The front view which shows 2nd Embodiment of this invention. The top view which shows 3rd Embodiment of this invention.

Explanation of symbols

1 Personal computer (electronic equipment)
15 Main board (circuit board)
16 IC board (heating element)
33 Heat receiving member 18 Heat exchanger (heat dissipation means)
35 Heat pipe (heat transfer means)
37 Pressing spring (pressing means)
46 steps

Claims (6)

A circuit board;
A heating element mounted on the circuit board;
A heat receiving member thermally connected to the heating element;
A heat radiating means for radiating heat of the heat receiving member;
One end is thermally connected to the heat receiving member, the other end is thermally connected to the heat radiating means, and a heat transfer means for transferring heat of the heat receiving member to the heat radiating means,
A pressing unit that presses the heat receiving member against the heating element by pressing a portion other than the portion to which the heat transfer unit of the heat receiving member is connected to the heating element;
An electronic apparatus comprising: The heat transfer means is at least one heat pipe that overlaps the heat receiving member in a plan view of the circuit board, and the pressing means is disposed in a portion where the heat pipe of the heat receiving member does not overlap in the plan view of the circuit board. The electronic device according to claim 1. The electronic apparatus according to claim 2, wherein a plurality of the heat pipes are disposed on the heat receiving member, and the pressing unit is disposed between the plurality of heat pipes. 3. The electronic apparatus according to claim 2, wherein one heat pipe is disposed on the heat receiving member, and the pressing means is disposed on both sides thereof. By providing a step portion on one side of the heat receiving member and arranging the heat pipe on the step portion, the heat receiving member, the heat pipe, and the pressure spring overlap each other when viewed in the surface direction of the heat receiving member. The electronic apparatus according to claim 2, wherein the electronic apparatus is used. The said pressing means is a leaf spring-like pressing spring that has a longitudinal direction parallel to the longitudinal direction of the heat pipe and presses the heat receiving member toward the heating element. The electronic device in any one of.

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