JP2007266518A - Heat dissipating structure, and information processing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat dissipating structure capable of efficiently dissipating heat from a heater to a heat sink when the heater is apart from the heat sink, and to provide an information processing apparatus. <P>SOLUTION: The heat dissipating structure includes: the heat sink (40); a thermally conductive elastic member (45) arranged between the heat sink and a first heater (21) with heat conductivity and elasticity; and a heat diffusion sheet (50) including a first part (51) of the heat diffusion sheet arranged between the heat conduction elastic member and the first heater, and a second part (52) of the heat diffusion sheet not arranged between the thermally conductive elastic member and the first heater. The heat sink is closely adhered to the thermally conductive elastic member. The thermally conductive elastic member is closely adhered to the first part of the heat diffusion sheet. The first part of the heat diffusion sheet is closely adhered to the first heater. The second part of the heat diffusion sheet is closely adhered to the heat sink. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a heat dissipation structure for cooling a heating element such as an IC package, and an information processing apparatus including the heat dissipation structure.

  A technique for cooling a heat generating element by dissipating heat from the heat generating element to a heat radiating plate is known. When the heat radiating plate cannot be brought into direct contact with the heat generating body, the heat generating body and the heat radiating plate are thermally connected by a heat transfer component.

  FIG. 7 shows a heat transfer component 120 described in Patent Document 1. The heat transfer component 120 is wrapped in a heat conductive heat diffusion sheet 121, a heat conductive heat diffusion sheet 122 bonded to the heat diffusion sheet 121 at the bonding portion 120a, and the heat diffusion sheet 121 and the heat diffusion sheet 122. Metal wool 123. In the heat transfer component 120, a difference is provided in the thickness corresponding to the difference between the distance between the heat generating element 101 and the heat radiating plate 110 and the distance between the heat generating element 102 and the heat radiating plate 110. Due to the repulsive force of the compressed metal wool 123, the thermal diffusion sheet 121 is in close contact with the heat radiating plate 110 having the refrigerant vent 111, and the thermal diffusion sheet 122 is in close contact with the heating elements 101 and 102 mounted on the printed wiring board 100. Therefore, the heating elements 101 and 102 and the heat radiating plate 110 are thermally connected by the heat transfer component 120.

  In the heat dissipation structure shown in FIG. 7, since the two heat diffusion sheets 121 and 122 and the metal wool 123 are sandwiched between the heat generating elements 101 and 102 and the heat dissipation plate 110, The thickness up to the heat radiating plate 110 is large. Further, since the height from the printed wiring board 100 is different between the heating element 101 and the heating element 102, it is difficult to make the heat transfer component 120 adhere to the heating element 101 and the heating element 102 with equal pressure.

  The heat transfer path from the heating element 102 to the heat radiating plate 110 includes a path through which heat generated in the heating element 102 is transferred in the order of the heat diffusion sheet 122, the metal wool 123, the heat diffusion sheet 121, and the heat dissipation plate 110, and heat generation. There is a path through which heat generated in the body 102 is transmitted in the order of the thermal diffusion sheet 122, the bonding portion 120 a, the thermal diffusion sheet 121, and the heat dissipation plate 110.

The contact points in the former heat transfer path are between the heating element 102 and the thermal diffusion sheet 122, between the thermal diffusion sheet 122 and the metal wool 123, between the metal wool 123 and the thermal diffusion sheet 121, and the thermal diffusion sheet 121. And between the heat radiating plate 110. There are three contact points in the latter heat transfer path: between the heating element 102 and the heat diffusion sheet 122, the adhesive portion 120 a, and between the heat diffusion sheet 121 and the heat dissipation plate 110.
Japanese Patent Laid-Open No. 10-294580

  An object of the present invention is to provide a heat dissipation structure and an information processing apparatus capable of efficiently dissipating heat from a heat generating element to a heat sink when the heat generating element and the heat sink are separated from each other.

  Hereinafter, means for solving the problem will be described using the numbers used in (Best Mode for Carrying Out the Invention). These numbers are added to clarify the correspondence between the description of (Claims) and (Best Mode for Carrying Out the Invention). However, these numbers should not be used to interpret the technical scope of the invention described in (Claims).

  The heat dissipation structure according to the present invention includes a heat sink (40), a heat conductive elastic member (45) having thermal conductivity and elasticity disposed between the heat sink and the first heating element (21), and the heat conductive elastic member. Thermal diffusion having a thermal diffusion sheet first portion (51) disposed between the first heating elements, a thermal diffusion elastic member, and a thermal diffusion sheet second portion (52) not disposed between the first heating elements. And a sheet (50). The heat sink and the heat conducting elastic member are in close contact with each other. The heat conducting elastic member and the heat diffusion sheet first portion are in close contact with each other. The first part of the thermal diffusion sheet and the first heating element are in close contact with each other. The second portion of the heat diffusion sheet is in close contact with the heat sink.

  Here, “adhesion” means that the members are brought into direct contact with each other, and the members are heated via an object that deforms in accordance with the shape of the member as exemplified by the adhesive or the heat conducting material (44). Connection.

  According to the present invention, a heat transfer path that thermally connects the first heating element (21) and the heat sink (40) that are separated from each other is formed. The heat generated in the first heating element (21) is transferred to the first part (51) of the thermal diffusion sheet and diffused from the first part (51) of the thermal diffusion sheet to the second part (52) of the thermal diffusion sheet. In the heat transfer path transmitted from the diffusion sheet second portion (52) to the heat sink (40), there are two contact points, and therefore the heat transfer efficiency is excellent. Furthermore, the deviation from the fixed value (ΔH) between the first heating element (21) and the heat sink (4) is absorbed by the heat conducting elastic member (45) which is an elastic body.

  In the heat dissipation structure according to the present invention, the front heat sink may include a heat dissipation plate (41) and a tube (43). Here, the pipe is a heat pipe or a pipe through which a coolant circulates. When the second portion of the heat diffusion sheet is in close contact with the tube, the first heating element is efficiently cooled.

  In the heat dissipation structure according to the present invention, the heat dissipation plate has a flat surface (41b) disposed on the first heat generating body side of the heat dissipation plate. When the tube is disposed along the plane so as to protrude from the plane, the heat dissipation structure according to the present invention is miniaturized.

  In the heat dissipation structure according to the present invention, the first heating element is disposed between the printed wiring board (31) on which the first heating element and the second heating element (22) are mounted and the thermal diffusion sheet. Also good. Here, when the heat sink is disposed so as to face the printed wiring board and is urged in the direction of the printed wiring board to come into close contact with the second heating element, the heat dissipation structure for cooling the two heating elements is small. It becomes.

  In the present invention, the thermal diffusion sheet is preferably a graphite sheet. The graphite sheet has excellent thermal diffusion performance.

  In the present invention, it is preferable that the first heating element and the first portion of the heat diffusion sheet are in close contact with each other via a heat conductive grease or a phase change sheet (44). Heat transfer between the first heating element and the first portion of the heat diffusion sheet is improved by the heat conductive grease or the phase change sheet.

  In the information processing apparatus having the heat dissipation structure (70, 70 ') according to the present invention, the IC package (21) is efficiently cooled by using the heat dissipation structure (70, 70'). Failure due to overheating is prevented.

  ADVANTAGE OF THE INVENTION According to this invention, when the heat generating body and the heat sink are separated, the heat radiating structure and information processing apparatus which can efficiently radiate heat from the heat generating body to the heat sink are provided.

  The best mode for carrying out a heat dissipation structure and an information processing apparatus according to the present invention will be described below with reference to the accompanying drawings.

(First embodiment)
FIG. 1 discloses an information processing apparatus 10 according to a first embodiment of the present invention. The information processing apparatus 10 includes a CPU 11, a storage device 12 such as a memory 16 and a hard disk device, an input device 13 such as a keyboard, a pointing device, and an operation switch, an optical disk drive device 14, and a display device 15. ing. In the information processing apparatus 10, the CPU 11 controls the optical disk drive device 14 and the display device 15 according to a program stored in the storage device 12. For example, the optical disk drive device 14 reads information stored in an optical disk such as a CD or a DVD in response to an input signal from the input device 13, and the display device 15 displays an image indicated by the read information. As the information processing apparatus 10, a notebook personal computer or desktop type in which a first casing provided with a keyboard and a second casing provided with a display device 15 are rotatably coupled by a hinge portion. A personal computer and a DVD player are exemplified.

  FIG. 3 shows a heat dissipation structure 70 provided in the information processing apparatus 10. The heat dissipation structure 70 is a system for cooling the IC packages 21 and 22 that are heating elements. The IC packages 21 and 22 are IC packages provided in the information processing apparatus 10.

  Hereinafter, the case where the IC package 21 is the memory controller hub (hereinafter referred to as MCH) 17 and the IC package 22 is the CPU 11 will be described as an example. The MCH 17 is responsible for the connection between the CPU 11 and the memory 16 as shown in FIG.

  As shown in FIG. 3, the IC packages 21 and 22 are mounted on the board surface 31 a of the printed wiring board 31.

  The heat sink 40 for cooling the IC packages 21 and 22 includes a metallic heat radiation plate 41 having a flat surface 41a and a flat surface 41b arranged on both sides in the thickness direction, and a tube 42 disposed along the flat surface 41a. And a tube 43 disposed along the plane 41b. The tube 42 and the tube 43 protrude on the plane 41a or the plane 41b. Each of the tubes 42 and 43 has a trapezoidal cross section perpendicular to the longitudinal direction (the direction perpendicular to the paper surface in FIG. 3). The tube 42 passes through the position where the IC package 22 is orthogonally projected onto the plane 41a. The tube 43 passes through the vicinity of the position where the IC package 21 is orthogonally projected onto the plane 41b. The pipes 42 and 43 are pipes through which a heat pipe or a coolant is circulated. The heat absorbed by the heat sink 40 from the IC packages 21 and 22 is diffused throughout the heat radiating plate 41 by the action of the tube 42 and the tube 43 and radiated into the atmosphere, or a cooling (not shown) provided separately from the heat radiating plate 41. Or taken to a vessel.

  The cross sections of the tube 42 and the tube 43 may be rectangular or semicircular. Further, the tube 42 may be disposed along the plane 41b similarly to the tube 43, and the tube 42 may pass through the vicinity of the position where the IC package 22 is orthogonally projected onto the plane 41b.

  A base 33 is fixed to the outside of each of the four corners of the IC package 22 on the substrate surface 31a. A male screw part 32 is screwed to each of the bases 33 so as to stand upright on the board surface 31a. The leg 32b of the male screw part 32 is inserted through a through hole 41c that penetrates the heat radiating plate 41 in the thickness direction. The male screw component 32 supports the heat sink 40 so that the flat surface 41b faces the substrate surface 31a. The heat sink 40 is movable along the leg portion 32b. The urging means 34 such as a compression coil spring is disposed between the head portion 32 a of the male screw part 32 and the flat surface 41 a and urges the heat sink 40 toward the printed wiring board 31.

  Here, it is possible to adjust the force for biasing the heat sink 40 in the direction of the printed wiring board 31 by changing the depth at which the male screw part 32 is screwed into the base 33.

  Since the heat sink 40 is urged toward the printed wiring board 31, the flat surface 41 b comes into pressure contact with the upper surface 22 a of the IC package 22. Here, when a heat conductive material 44 having a high thermal conductivity such as a heat conductive grease or a phase change sheet is provided between the flat surface 41b and the upper surface 22a, the surface roughness is formed between the flat surface 41b and the upper surface 22a. Since the gap is filled with the heat conductive material 44, heat transfer between the flat surface 41b and the upper surface 22a is improved.

  The phase change sheet is in a solid state at room temperature, but has a property of softening when the temperature reaches a certain value (about 60 ° C.) or more and closely contacting the upper surface 22a and the flat surface 41b. Since the phase change sheet can be reused when the IC package 21 is replaced, it is suitable for a notebook personal computer.

  When the heat sink 41 shares the same plane 41b in the vicinity of the IC package 21 and in the vicinity of the IC package 22, the distance H between the plane 41b and the substrate surface 31a is not less than the height H2 from the substrate surface 31a of the IC package 22. Here, since the height H1 from the substrate surface 31a of the IC package 21 is lower than the height H2, it is difficult to directly press the upper surface 21a of the IC package 21 and the flat surface 41b.

  Therefore, the heat dissipation structure 70 includes a heat conducting rubber member 45 and a heat diffusion sheet 50 such as a graphite sheet in order to improve heat transfer from the IC package 21 to the heat sink 40. The heat conducting rubber member 45 has thermal conductivity and elasticity, and other members other than rubber may be used as long as they have elasticity. The heat conducting rubber member 45 includes a flat surface 45a that faces the flat surface 41b, and a flat surface 45b that is disposed on the opposite side of the flat surface 45a and faces in a direction opposite to the direction in which the flat surface 45a faces. The heat diffusion sheet 50 has a property of efficiently diffusing heat in a direction along the sheet surface and flexing flexibly with respect to an external force. The thermal diffusion sheet 50 includes a first portion 51 disposed between the flat surface 45b and the upper surface 21a, and a second portion 52 not disposed between the flat surface 45b and the upper surface 21a. For example, the first portion 51 is a central portion of the thermal diffusion sheet 50, and the second portion 52 is a peripheral portion of the thermal diffusion sheet 50. The first portion 51 includes a sheet surface 51a and a sheet surface 51b on both sides in the thickness direction, and the second portion 52 includes a sheet surface 52a and a sheet surface 52b on both sides in the thickness direction. The sheet surface 51a and the sheet surface 52a are continuous, and the sheet surface 51b and the sheet surface 52b are continuous. The sheet surface 51a faces the flat surface 45b, and the sheet surface 51b faces the upper surface 21a. Since the sheet surface 52a is in close contact with the tube 43, the heat transfer path from the IC package 21 to the tube 43 is short, and the heat generated in the IC package 21 is efficiently radiated.

  Here, since the heat sink 40 is biased toward the printed circuit board 31, the flat surface 45a is pressed against the flat surface 41b, the flat surface 45b is pressed against the sheet surface 51a, and the sheet surface 51b is pressed against the upper surface 21a. Here, heat transfer between the sheet surface 51b and the upper surface 21a may be improved by providing the heat conductive material 44 between the sheet surface 51b and the upper surface 21a. However, when a flexible member such as a graphite sheet is used for the thermal diffusion sheet 50, it is sufficient that the sheet surface 51b and the upper surface 21a are in direct contact with each other.

  Therefore, the heat of the IC package 21 is radiated to the heat sink 40 by the two heat transfer paths. In the first heat transfer path, heat generated in the IC package 21 is transferred to the first portion 51, diffused from the first portion 51 to the second portion 52, and transferred from the second portion 52 to the tube 43. It is a route. There are two contact points in the heat transfer path between the upper surface 21 a and the sheet surface 51 b and between the sheet surface 52 a and the tube 43. The second heat transfer path is a path through which heat generated in the IC package 21 is transferred in the order of the first portion 51, the heat conducting rubber member 45, and the heat radiating plate 41. There are three contact points in the heat transfer path between the upper surface 21a and the sheet surface 51b, between the sheet surface 51a and the flat surface 45b, and between the flat surface 45a and the flat surface 41b. In these heat transfer paths, since there are few contact points, the heat of the IC package 21 is efficiently radiated to the heat sink 40.

  Here, the distance ΔH between the upper surface 21a and the flat surface 41b does not become a constant value due to an attachment error of the IC packages 21 and 22 to the printed wiring board 31 or the like. In the heat dissipation structure 70, the heat conducting rubber member 45, which is an elastic member, absorbs the deviation of ΔH from a constant value.

  According to the heat dissipation structure 70, it is possible to efficiently cool a plurality of IC packages mounted on the same printed wiring board with a single heat sink. Failure due to 10 overheating is prevented.

  Since the tube 43 protrudes to the flat surface 41b side, it does not affect the space on the flat surface 41a side and contributes to downsizing the heat dissipation structure 70. If the tube 43 does not protrude toward the flat surface 41a, the heat dissipation structure 70 is further reduced in size. Note that a part of the pipe 43 may enter the inside of the heat radiating plate 41, but if the pipe is embedded in the heat radiating plate 41, the thickness of the heat radiating plate 43 increases, so the pipe 43 is provided on the flat surface 41b. It is preferable that

  If an IC package that generates a large amount of heat or is weak at high temperatures is disposed as the IC package 22, such an IC package can be efficiently cooled.

(Second Embodiment)
FIG. 4 shows a peripheral portion of the IC package 21 of the heat dissipation structure 70 ′ according to the second embodiment of the present invention. 4A is a cross-sectional view of the heat dissipation structure 70 ′ cut along a plane perpendicular to the longitudinal direction of the tube 42 ′. FIG. 4B is a cross-sectional view of the heat dissipation structure 70 ′ parallel to the longitudinal direction of the tube 42 ′. It is sectional drawing cut by a plane. In the heat dissipating structure 70 ′, a pipe 42 ′ is provided instead of the pipe 43, and the sheet surface 52 a is in close contact with the flat surface 41 b at one place and is in close contact with the pipe 42 ′ at other places. Is different from the heat dissipation structure 70, and the others are the same as the heat dissipation structure 70. The pipe 42 ′ is a heat pipe or a pipe through which the coolant is circulated along the flat surface 41 a, and is in close contact with the sheet surface 52 a at a portion protruding from the heat radiating plate 41. The tube 42 'passes through the position where the IC package 21 is orthogonally projected onto the plane 41a.

  In the heat dissipation structure 70 ′, similarly to the heat dissipation structure 70, the heat transfer between the sheet surface 51b and the upper surface 21a may be improved by providing the heat conductive material 44 between the sheet surface 51b and the upper surface 21a. However, when a flexible member such as a graphite sheet is used for the thermal diffusion sheet 50, it is sufficient that the sheet surface 51b and the upper surface 21a are in direct contact with each other.

  FIG. 5 shows a heat dissipation structure 71 having a configuration in which the heat diffusion sheet 50 is removed from the heat dissipation structure 70 ′.

  FIG. 6 shows an experimental result in which the temperature of the IC package 21 when the temperature of the tube 42 ′ is set to about 60 ° C. is compared between the case of the heat dissipation structure 71 and the case of the heat dissipation structure 70 ′. The temperature of the IC package 21 in the case of the heat dissipation structure 70 ′ was approximately 5 ° C. lower than the temperature of the IC package 21 in the case of the heat dissipation structure 71. This indicates that in order to dissipate the heat generated in the IC package 21 to the heat sink 40, the heat transfer efficiency is improved by using the heat diffusion sheet rather than using the heat conducting rubber member.

  In the heat dissipation structure 70 ′, the pipe 42 ′ may be provided so as to pass through a position 41 d obtained by orthogonally projecting the position where the second portion 52 of the thermal diffusion sheet 50 is in contact with the plane 41 b to the plane 41 a.

FIG. 1 is a block diagram of an information processing apparatus according to the first embodiment of the present invention. FIG. 2 is a block diagram for explaining the MCH. FIG. 3 is a cross-sectional view showing the heat dissipation structure according to the first embodiment of the present invention. FIG. 4 is a cross-sectional view showing a heat dissipation structure according to the second embodiment of the present invention. FIG. 5 is a cross-sectional view showing a heat dissipation structure that does not have a thermal diffusion sheet. FIG. 6 is a diagram showing experimental results. FIG. 7 is a view showing a conventional heat transfer component.

Explanation of symbols

10 ... Information processing apparatus 11 ... CPU
12 ... Storage device 13 ... Input device 14 ... Optical disk drive device 15 ... Display device 16 ... Memory 17 ... MCH
21, 22 ... IC packages 21a, 22a ... Upper surface 31 ... Printed wiring board 31a ... Board surface 32 ... Male screw part 32a ... Head 32b ... Leg 33 ... Base 34 ... Biasing means 40 ... Heat sink 41 ... Heat sinks 41a, 41b ... Plane 41c ... Through hole 41d ... Position 42, 42 ', 43 ... Pipe 44 ... Heat conduction material 45 ... Heat conduction rubber members 45a, 45b ... Plane 50 ... Heat diffusion sheet 51 ... First part 52 ... Second parts 51a, 51b 52a, 52b ... sheet surfaces 70, 70 ', 71 ... heat dissipation structure 100 ... printed circuit board 101, 102 ... heating element 110 ... heat dissipation plate 111 ... refrigerant vent 120 ... heat transfer component 120a ... adhesive part 121, 122 ... heat Diffusion sheet 123 ... metal wool

Claims (7)

A heat sink,
A thermally conductive elastic member having thermal conductivity and elasticity disposed between the heat sink and the first heating element;
A thermal diffusion having a first thermal diffusion sheet disposed between the heat conducting elastic member and the first heating element, and a second thermal diffusion sheet not disposed between the thermal conducting elastic member and the first heating element. A sheet,
The heat sink and the heat conducting elastic member are in close contact,
The heat conducting elastic member and the heat diffusion sheet first portion are in close contact,
The first portion of the thermal diffusion sheet and the first heating element are in close contact with each other,
A heat dissipation structure in which the second portion of the heat diffusion sheet is in close contact with the heat sink. The heat sink includes a heat sink and a tube,
The heat diffusion sheet second portion is in close contact with the tube;
The heat dissipation structure according to claim 1, wherein the pipe is a heat pipe or a pipe through which a coolant circulates. The heat sink has a flat surface;
The plane is disposed on the first heating element side of the heat sink,
The heat dissipation structure according to claim 2, wherein the tube is disposed along the plane so as to protrude from the plane. The first heating element is disposed between a printed wiring board on which the first heating element and the second heating element are mounted and the thermal diffusion sheet,
4. The heat dissipation structure according to claim 1, wherein the heat sink is disposed so as to face the printed wiring board, and is urged in the direction of the printed wiring board to be in close contact with the second heating element. . The heat dissipation structure according to claim 1, wherein the thermal diffusion sheet is a graphite sheet. The heat dissipation structure according to any one of claims 1 to 5, wherein the first heating element and the first portion of the thermal diffusion sheet are in close contact with each other via a thermal conductive grease or a phase change sheet. An information processing apparatus comprising the heat dissipation structure according to any one of claims 1 to 6.

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