JP2014036066A - Shield case having heat radiation effect and circuit unit including the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a shield case which achieves large design flexibility and has a heat radiation effect.SOLUTION: A shield case 10 is used for shielding a circuit board 3 on which an integrated circuit 2 is mounted. The shield case 10 uses a conductive film formed by bonding a metal foil 14 to a resin film 15 and includes a cover part 11, a heat absorption part 13, and a ground part 12. The cover part 11 has a shape that covers the circuit board 3, and the heat absorption part 13 is formed by disposing a part of the metal foil 14 on the integrated circuit 2. The ground part 12 is formed by placing another part of the metal foil 14, which is different from the heat absorption part 13, in contact with a ground of the circuit board 3.

Description

  The present invention relates to a shield case having a heat dissipation effect with a simple configuration and a circuit unit including the same.

  The processing speed of digital electronic circuits mounted on various electronic devices such as personal computers, mobile phones, and liquid crystal televisions is increasing. This is due to higher technology of semiconductor processes. Accordingly, the clock frequency and data transmission speed of the circuit are increased, and electromagnetic noise is easily generated. Therefore, it is required to shield the electromagnetic noise.

  Furthermore, as the integration of semiconductor processes has advanced, the power consumption density of electronic circuits continues to increase, and the problem of heat dissipation is becoming increasingly important.

  In consideration of the above circumstances, Patent Document 1 discloses a shield case having a heat sink function. FIG. 8 is a cross-sectional view for explaining the electronic component heat dissipation structure of Patent Document 1. In FIG. Heat generating components 102 and 103 are mounted on the printed circuit board 101, and a shield case 104 is attached to the printed circuit board 101 to cover the whole. In the shield case 104, crown portions 105 and 106 are formed in portions corresponding to the heat generating components 102 and 103, and a concave groove 107 is formed around the crown portions 105 and 106. In the crown portions 105 and 106, the top portions of the heat generating components 102 and 103 are fitted. According to this structure, the conductive area between the heat generating components 102 and 103 and the shield case 104 is large, the thermal conductivity is improved, the surface area of the shield case 104 is increased, and the heat dissipation effect from the shield case 104 is also increased. Demonstrate.

JP 2006-222146 A (published August 24, 2006)

  By the way, since the shield case of patent document 1 forms a crown part in the part which hits a heat-emitting component, it is necessary to manufacture a shield case with high precision. Even if the shield case can be manufactured with high precision, if the position and height of the heat generating component mounted on the printed circuit board are slightly shifted, the crown and the heat generating component will not be aligned. High precision is also required for the manufacture of For this reason, high accuracy is required for the production of the shield case and the printed circuit board.

  Further, when manufacturing a shield case to be attached to a printed circuit board having different arrangements of heat generating components, it is necessary to newly manufacture a mold for manufacturing the shield case. For this reason, it is necessary to prepare a mold for manufacturing a shield case according to the number of types of printed circuit boards, which is troublesome.

  The present invention has been made in view of such problems, and the object thereof is to easily form a shape suitable for a circuit board to which a shield case is attached, and has a heat radiation effect with a high degree of freedom in design design. It is to realize a shield case.

  A shield case according to the present invention is a shield case for shielding a circuit board on which an integrated circuit is mounted. The shield case uses a conductive film in which a metal foil and a resin film are bonded together, and has a covering portion, an endothermic structure. And the covering portion has a shape that covers the circuit board, the heat absorbing portion is configured by arranging a part of the metal foil on the integrated circuit, and the grounding portion includes the heat absorbing portion and the heat absorbing portion. Is characterized in that a part of another metal foil is formed in contact with the ground of the circuit board.

  Further, the grounding portion may be configured by folding a part of the conductive film so that the outer side in contact with the ground of the circuit board is a metal foil. Further, the grounding part may have a screw hole through which a screw for attaching to the circuit board is passed. Further, the endothermic portion may be configured by a plurality of portions of metal foil.

  According to the present invention, a shield case having a heat dissipation effect can be mounted on various circuit boards.

It is a disassembled perspective view of the circuit unit by which the shield case which concerns on Embodiment 1 was mounted. 2 is a cross-sectional view of a circuit unit according to Embodiment 1. FIG. 3 is a development view of a shield case according to Embodiment 1. FIG. 6 is a development view of a shield case according to Embodiment 2. FIG. It is a disassembled perspective view of the circuit unit by which the shield case which concerns on Embodiment 3 was mounted. It is sectional drawing and the side view of a circuit unit concerning Embodiment 3. 6 is a development view of a shield case according to Embodiment 3. FIG. It is sectional drawing of the thermal radiation apparatus of patent document 1. FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings of the present invention, the same reference numerals represent the same or corresponding parts. In addition, the dimensional relationships such as the length, width, thickness, and depth of each portion are appropriately changed for clarity and simplification of the drawings, and do not represent actual dimensional relationships.

Embodiment 1
FIG. 1 is an exploded perspective view of a circuit unit 1 having a heat dissipation effect and a shield case 10 that shields electromagnetic noise according to the first embodiment. FIG. 2A is a circuit unit shown in FIG. It is sectional drawing of AA 'part of 1. FIG. FIG. 2B is an enlarged cross-sectional view of a part of the shield case 10. The circuit unit 1 includes an integrated circuit 2, a circuit board 3, and a shield case 10. The integrated circuit 2 is mounted on the circuit board 3, and the shield case 10 is disposed so as to cover the circuit board 3 with respect to the surface including the integrated circuit 2.

  The integrated circuit 2 includes an LSI (Large Scale Integration), an SoC (System-on-a-Chip), and the like, and processes digital signals at high speed. The circuit board 3 mounts various electronic components including the integrated circuit 2 on the surface, and forms a pattern wiring on the board. The circuit board 3 has a plurality of screw holes 4 at the corners of the board, and the circuit board 3 can be fixed to a housing (not shown) by screwing. In addition, ground pattern wiring is formed around the screw hole 4, and the ground pattern wiring of the circuit board 3 can be dropped to the frame ground by screwing. In FIG. 1, four screw holes 4 are provided. However, the number is limited to this number as long as the circuit unit 1 can be fixed to the housing and the ground pattern wiring of the circuit board 3 can be dropped to the frame ground. is not.

  The shield case 10 is made of a conductive film in which a metal foil 14 and a resin film 15 are bonded together as shown in FIG. The metal foil 14 is made of a highly conductive material such as aluminum, copper, or gold, and has a thickness of several tens of μm. The resin film 15 is made of an insulating material such as polyester and has a thickness of about 100 μm. In this embodiment, the composite film 16 which bonded aluminum foil and the polyester film as the electroconductive film was used. The composite film 16 has been conventionally used to block electromagnetic noise, and further has excellent heat resistance, and thus can be said to be suitable as a material for the shield case 10 of the present invention. In addition, since the conductive film such as the composite film 16 used in the present invention is configured as described above, it can be easily processed. Therefore, the shield case 10 with a high degree of freedom in design can be realized.

  When the shield case 10 is joined to the circuit board 3, the surface with respect to the circuit board 3 is a resin film 15 and the opposite outer surface is a metal foil 14. If the surface of the circuit board 3 with respect to the metal foil 14 is used, the metal foil 14 may come into contact with various electronic components including the integrated circuit 2 mounted on the circuit board 3 to cause a short circuit. Therefore, the surface with respect to the circuit board 3 is a resin film 15.

  The shield case 10 includes a covering part 11, a grounding part 12, and a heat absorbing part 13. The covering portion 11 constitutes the exterior of the shield case 10 and includes a top surface 17 and side surfaces 18. The top surface 17 has substantially the same size and shape as the circuit board 3. The side surface 18 forms the side surface of the shield case 10, and a space is provided between the top surface 17 and the circuit board 3 so that the shield case 10 and the circuit board 3 do not contact each other. Further, the side surface 18 is fixed by soldering or the like at a portion in contact with the circuit board 3 in order to join the shield case 10 and the circuit board 3. The covering portion 11 is formed so as to cover the circuit board 3 with respect to the surface including the integrated circuit 2, and serves to protect the integrated circuit 2 and the circuit board 3 and electromagnetic noise generated from the integrated circuit 2 and the circuit board 3. Has the role of shielding.

  The grounding portion 12 has a role of bringing the metal foil 14 of the shield case 10 into conduction with the ground pattern wiring of the circuit board 3 and grounding. The grounding portion 12 is configured such that a part of the metal foil 14 is in contact with the ground pattern wiring of the circuit board 3. In the first embodiment, a part of the composite film 16 is folded back so that the outer surface becomes the metal foil 14. Configured. With this configuration, the metal foil 14 can be joined to and grounded with the ground pattern wiring around the screw hole 4 of the circuit board 3, so that the metal foil 14 of the shield case 10 can be dropped to the frame ground. .

  By dropping the metal foil 14 of the shield case 10 to the frame ground, charging to the shield case 10 can be prevented. The shield case 10 shields electromagnetic noise generated from the integrated circuit 2 and the circuit board 3 at the covering portion 11. If the metal foil 14 is not dropped on the frame ground, the shield case 10 is charged by the received electromagnetic noise. If the charge amount is large, there is a risk of electric shock when the circuit unit 1 is touched. In order to prevent such a problem, the shield case 10 is prevented from being charged by dropping the metal foil of the shield case 10 to the frame ground.

  The heat absorbing unit 13 has a role of absorbing heat generated by the integrated circuit 2 and keeping the temperature of the integrated circuit 2 below a certain temperature. In the integrated circuit 2, a current flows for processing, and heat is generated by the power consumption. The heat generation causes a failure of the integrated circuit 2 and a decrease in life. Therefore, it is necessary to absorb the heat of the integrated circuit 2.

  The heat absorption part 13 of the first embodiment is configured by arranging a part of the metal foil 14 on the integrated circuit 2, and the metal foil 14 having high thermal conductivity absorbs the heat of the integrated circuit 2. The heat transmitted to the heat absorbing unit 13 is transmitted to the covering unit 11, the grounding unit 12, and the casing of the shield case 10 and dispersed or radiated to the surrounding space. When the heat absorbing portion 13 is disposed on the integrated circuit 2, a double-sided tape or the like may be used to firmly fix the heat absorbing portion 13. Further, in order to efficiently absorb the heat of the integrated circuit 2, it is preferable that the heat absorbing portion 13 is disposed on the entire surface of the integrated circuit 2.

  Further, a heat conductive sheet may be provided between the heat absorbing unit 13 and the integrated circuit 2. By providing the thermal conductive sheet, the heat of the integrated circuit 2 can be more efficiently absorbed by the metal foil 14 of the heat absorbing portion 13.

  FIG. 3 is a development view of the shield case 10 according to the first embodiment. The shield case 10 is manufactured by cutting a single composite film 16 into a predetermined shape and bending it. The front surface of FIG. 3 is a metal foil 14, and the back surface is a resin film 15.

  The covering portion 11 includes a top surface 17 and a side surface 18, and side surfaces 18 having the same width are formed on the four sides of the top surface 17. The side surface 18 can be formed by 90-degree mountain folding along the broken line 21 and 90-degree valley folding along the broken line 22. In the first embodiment, in order to be suitable for the rectangular circuit board 3, the covering portion 11 includes the rectangular top surface 17 and the four side surfaces 18, but is not limited thereto. The covering portion 11 only needs to be formed so as to cover the circuit board 3 with respect to the surface including the integrated circuit 2, and the covering portion 11 may be configured according to the shape of the circuit board 3.

  The grounding portion 12 is formed at an end of a certain side surface 18 and can be formed by folding back along a broken line 23 by mountain folding. By doing in this way, since the metal foil 14 can be joined to the ground pattern wiring around the screw hole 4 of the circuit board 3, the metal foil of the shield case 10 can be dropped to the frame ground.

  In the first embodiment, the grounding portion 12 is formed at the end of the side surface 18, but is not limited to this shape. The grounding portion 12 may be formed by bending the composite film 16 in accordance with the position of the ground pattern wiring formed on the circuit board to which the shield case 10 is attached. Therefore, the grounding portion 12 can be formed on the shield case 10 according to the configuration and shape of the circuit board. Moreover, the grounding part 12 may be provided in several places.

  The heat absorption part 13 is formed in the protrusion part 19 protruding from the top surface 17. A fold-back is performed along the broken line 24 between the protruding portion 19 and the top surface 17, a 90-degree valley fold is formed along the broken line 25 in the protruding portion 19, and a 90-degree fold is formed along the broken line 26. By doing so, the heat absorbing portion 13 at the tip of the protruding portion 19 can be disposed on the integrated circuit 2. At this time, by disposing the heat absorbing portion 13 on the entire surface of the integrated circuit 2, heat can be efficiently absorbed.

  In the first embodiment, the endothermic portion 13 is formed at the tip of the protruding portion 19 protruding from the top surface 17, but is not limited to this shape. What is necessary is just to arrange | position metal foil on the integrated circuit mounted on the circuit board, and what is necessary is just to form the heat absorption part 13 according to the position of an integrated circuit. Further, the position and length of the protruding portion 19 may be matched with the position of the integrated circuit mounted on the circuit board. Therefore, the heat absorption part 13 can be formed in the shield case 10 according to the configuration and shape of the circuit board. In addition, a plurality of protrusions 19 including the heat absorption part 13 may exist.

  As described above, the shield case 10 having the heat radiation effect is realized by forming the composite film 16 obtained by bonding the metal foil 14 and the resin film 15 and including the covering portion 11, the grounding portion 12, and the heat absorbing portion 13. Can do. Further, the shield case 10 can be manufactured by cutting into a predetermined shape and bending according to the configuration and shape of the circuit board to which the composite film 16 is attached.

  For example, since the circuit board 3 of the first embodiment has a rectangular shape, the shape of the shield case 10 is made to be a substantially rectangular shape in accordance with the circuit board 3, but is not limited thereto. The shield case 10 can be manufactured according to the shape of the circuit board. Moreover, since the integrated circuit 2 of Embodiment 1 was mounted in the approximate center of the circuit board 3, the protrusion part 19 which has the heat absorption part 13 was comprised according to it, However, It is not restricted to this. What is necessary is just to comprise the protrusion part 19 according to the mounting position of the integrated circuit 2. FIG.

  Further, by adjusting the width of the side surface 18 that forms the height of the shield case 10, the size of the circuit unit 1 on which the shield case 10 is mounted can be freely changed.

  Further, the circuit unit 1 on which the shield case 10 is mounted can be mounted on various electronic devices.

[Embodiment 2]
The shield case of the second embodiment is different from the shield case of the first embodiment in that an opening 31 is provided on the top surface 17 of the covering portion 11, but the other configurations and the respective roles are the same.

  FIG. 4 is a development view of the shield case 30 according to the second embodiment. By providing a plurality of openings 31 in the shield case 30, the heat generated between the shield case 30 and the circuit board 3 can be released from the openings 31 to the outside of the circuit unit 1. Therefore, the heat dissipation effect of the integrated circuit 2 can be enhanced.

  The shape of the opening 31 is not limited to a circle or a rectangle. However, the physical strength of the shield case 30 is ensured by making the opening 31 circular.

  Moreover, it is preferable that the magnitude | size of the opening part 31 is 25 mm or less. Electromagnetic noise generated from the integrated circuit 2 and the circuit board 3 has a wide range of frequencies, which causes other electric appliances to malfunction and interfere with communication radio waves. For this reason, there is a regulation for suppressing the emission of electromagnetic noise, in which a frequency range of 30 MHz to 6 GHz is regulated. Therefore, by setting the size of the opening 31 to 25 mm or less, it is possible to suppress leakage of electromagnetic noise having a frequency of 30 MHz to 6 GHz from the opening 31 to the outside of the circuit unit 1.

[Embodiment 3]
The shield case of the third embodiment is different from the shield case of the first embodiment in the shape of the grounding part and the number of heat absorbing parts, but the other configurations and the respective roles are the same. FIG. 5 is an exploded perspective view of the circuit unit 1a on which the shield case 40 having a heat dissipation effect according to the third embodiment is mounted, and FIG. 6 is a cross-sectional view of the BB ′ portion of the circuit unit 1a shown in FIG. It is. The circuit unit 1a includes an integrated circuit 2, a circuit board 3, and a shield case 40. The integrated circuit 2 and the circuit board 3 have the same configuration as that of the first embodiment.

  The shield case 40 is made of the composite film 16 that is a conductive film, and includes a covering portion 41, four grounding portions 42, and four heat absorbing portions 43. The covering portion 41 constitutes the exterior of the shield case 40 as in the first embodiment, and includes a top surface 44 and a side surface 45.

  FIG. 7 is a development view of the shield case 40 according to the first embodiment. 3, the front surface of FIG. 7 is a metal foil 14, and the back surface is a resin film 15.

  The covering portion 41 includes a top surface 44 and side surfaces 45, and side surfaces 45 having the same width are formed on the four sides of the top surface 44. The side surface 18 can be formed by making a 90-degree mountain fold along the broken line 51 between the top surface 44 and the side surface 45.

  The grounding portion 42 is configured at the tip of a protruding portion 46 formed at the corner of the top surface 44, and a plurality of protruding portions 46 are formed. The protruding portion 46 has two screw holes 47, and the two screw holes 47 are overlapped by being folded back by a mountain fold along the broken line 52. At this time, the metal foil 14 is on the outside. Further, 90-degree valley folding is performed along the broken line 53 between the screw hole 47 and the top surface 44, and 90-degree mountain folding is performed along the broken line 54. By doing so, legs that support the corners of the shield case 40 are formed, and the screw holes 47 are arranged at positions corresponding to the screw holes 4 of the circuit board 3. This operation is performed for each circuit unit 1.

  As a result, the ground portion 42 is joined to the ground pattern wiring around the screw hole 4. Further, the shield case 40 and the circuit board 3 are joined by screwing and fixed to a housing (not shown), whereby the metal foil 14 of the shield case 40 and the ground pattern wiring of the circuit board 3 are made conductive, and the shield case 40 The metal foil 14 can be dropped to the frame ground.

  As described above, the grounding portion 12 includes the screw hole 47 and is disposed at a position corresponding to the screw hole 4 of the circuit board 3, so that the shield case 40 and the circuit board 3 can be easily fixed. Further, the metal foil 14 around the screw hole 47 of the grounding portion 12 is designed to be joined to the ground pattern wiring around the screw hole 4 of the circuit board 3, so that the metal foil 14 of the shield case 40 can be fixed at the same time as the frame ground. Can be dropped.

  In the third embodiment, the grounding portions 42 are provided in the same number as the screw holes 4 of the circuit board 3. However, the metal foil 14 of the shield case 40 is grounded while fixing the shield case 40 and the circuit board 3 to a housing (not shown). If it can be made, it is not restricted to this number.

  The heat absorption part 43 has substantially the same role and configuration as in the first embodiment, but differs from the first embodiment in that a plurality of protrusions 48 having the heat absorption part 43 are formed on each side of the top surface 44. . As in the first embodiment, each protruding portion 48 is folded back by a mountain fold along a broken line 55 between the protruding portion 48 and the top surface 44, and is 90-degree valley folded along a broken line 56 in the protruding portion 48. Fold 90 degrees along the broken line 57. By doing so, the heat absorbing portion 43 at the tip of the protruding portion 48 can be disposed on the integrated circuit 2. When this operation is performed on all the protrusions 48, the metal foil 14 is disposed on the entire surface of the integrated circuit 2 by all the heat absorbing portions 43. By providing the plurality of heat absorbing portions 13, the heat of the integrated circuit 2 can be dispersed, so that the heat can be absorbed more efficiently.

  As described above, by making the grounding portion 42 have the screw hole 47, the metal foil 14 of the shield case 40 can be dropped to the frame ground while the shield case 40 and the circuit board 3 are easily fixed. Moreover, it becomes possible to absorb heat more efficiently by providing two or more heat absorption parts 43. FIG.

  Further, the reason why the configuration of the shield case 40 can be greatly changed from that of the first embodiment as in the third embodiment is that the shield case 40 is formed from the composite film 16. Since the conductive film such as the composite film 16 used in the present invention is very thin, it can be easily processed. Therefore, the shield case 10 with a high degree of freedom in design can be realized.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to said embodiment, The range of this invention is shown by a claim, and the meaning and range equivalent to a claim All changes within are intended to be included.

DESCRIPTION OF SYMBOLS 1, 1a Circuit unit 2 Integrated circuit 3 Circuit board 4 Screw hole 10, 30, 40 Shield case 11, 41 Cover part 12, 42 Grounding part 13, 43 Heat absorption part 14 Metal foil 15 Resin film 16 Composite film 17, 44 Top surface 18, 45 Side surface 19 Protruding part 21, 22, 23, 24, 25, 26, 51, 52, 53, 54, 55, 56, 57 Broken line 31 Opening part 46 Protruding part 47 Screw hole 48 Protruding part

Claims (5)

A shield case for shielding a circuit board on which an integrated circuit is mounted,
The shield case uses a conductive film obtained by bonding a metal foil and a resin film, and includes a covering part, a heat absorbing part, and a grounding part,
The covering portion has a shape that covers the circuit board,
The heat absorption part is configured by arranging a part of the metal foil on the integrated circuit,
The grounding part is configured by a part of the metal foil different from the heat absorbing part being in contact with the ground of the circuit board.   2. The shield case according to claim 1, wherein the ground portion is configured by folding a part of the conductive film so that an outer side in contact with the ground of the circuit board becomes the metal foil.   The shield case according to claim 1, wherein the grounding portion has a screw hole through which a screw for attaching to the circuit board is passed.   The said heat absorption part is comprised by the some part of the said metal foil, The shield case in any one of Claims 1-3 characterized by the above-mentioned.   A circuit unit comprising a circuit board on which the shield case according to claim 1 and an integrated circuit are mounted.