Electronic device

Abstract

To provide means capable of achieving at least one of the minimization of a dead space in fixing a heat sink to a substrate and the minimization of a cost increase due to heat sink processing.SOLUTION: An electronic apparatus includes: a substrate 1; an IC 4 provided on the substrate 1; a heat sink 2 for dissipating heat emitted from the IC 4; and a holder 3 holding the heat sink 2 such that the protrusion 2c of the heat sink 2 is exposed. The holder 3 is mounted on the substrate 1 such that the protrusion 2c of the heat sink 2 is located on the IC 4.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to an electronic device equipped with a heat sink. [Background technology]

[0002] Electronic devices such as AV receivers are provided with heat sinks to dissipate heat from electrical components such as power transistors. Heat sinks for dissipating heat from electrical components surface-mounted on a board may be fixed as shown in (a) or (b) below.

[0003] (a) As shown in Figure 12, the heat sink is placed on the board and fixed with screws from the board side. In this case, the board needs an area to attach the heat sink closely. This area makes it impossible to arrange components or wire patterns, resulting in a dead space on the board.

[0004] (b) As described on the Thermal Components website at https: / / www.thermal.co.jp / pdf / clipset / tcp_set.pdf, the heat sink is fixed to the board with clips or spring-loaded clips. In this case, the only dead space in the board is the hole. However, there is a problem in that additional processing such as cutting fins into the heat sink is required.

[0005] In addition to the above (a) and (b), it is also possible to use clip terminals fixed by solder to fix the heat sink to the board. Patent Document 1 also discloses an invention that "includes fastening means (5) in the form of hook means (6) mounted on the surface of a circuit board (2) and holding means (7) mounted on a cooling member (4) (corresponding to a "heat sink") and cooperating with the hook means, the holding means (7) being resilient and spring-engageable with the hook means. The fastening means (5) acts to resiliently press the cooling member (4) against the shielding cover (3) and against the component (1)" (see abstract). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Special Publication No. 09-511620 Summary of the Invention [Problem to be solved by the invention]

[0007] For example, it is possible to reduce costs by not performing additional soldering on a board on which an HDMI (registered trademark) IC is mounted, and to avoid increasing costs by minimizing the effective size of the board as much as possible. In this respect, the dead space on the board where the heat sink is fixed is inefficient and is a problem that should be avoided. Similarly, it is desirable to minimize the increase in unit price of parts due to processing of the heat sink.

[0008] An object of the present invention is to provide a means for enabling at least one of minimizing dead space when fixing a heat sink to a substrate and minimizing increased costs due to processing of the heat sink. [Means for solving the problem]

[0009] The electronic device of the first invention comprises a substrate, a component mounted on the substrate, a heat sink for dissipating heat generated by the component, and a holder for holding the heat sink so that the bottom of the heat sink is exposed, and is characterized in that the holder is attached to the substrate so that the bottom of the heat sink is positioned above the component.

[0010] In the present invention, the heat sink is attached to the substrate by the holder, so that the increase in cost due to processing of the heat sink can be minimized. In addition, the holder increases the degree of freedom in design, so that the dead space when fixing the heat sink to the substrate can be minimized.

[0011] An electronic device according to a second aspect of the present invention is the electronic device according to the first aspect of the present invention, characterized in that the holder is made of resin.

[0012] In the present invention, the holder is made of resin. This allows for greater freedom in holder design. Also, unlike metal, patterns can be drawn on the board without worrying about short circuits. This allows for even greater minimization of dead space when fixing the heat sink to the board.

[0013] An electronic device according to a third aspect of the present invention is the electronic device according to the first or second aspect of the present invention, characterized in that the holder is made of polypropylene.

[0014] An electronic device according to a fourth aspect of the present invention is the electronic device according to any one of the first to third aspects of the present invention, further comprising a thermally conductive sheet provided between the component and the heat sink.

[0015] An electronic device according to a fifth aspect of the present invention is the electronic device according to the fourth aspect of the present invention, characterized in that the thermally conductive sheet has elasticity.

[0016] The electronic device of the sixth invention is an electronic device of any of the first to fifth inventions, characterized in that the holder has a substantially rectangular frame with a hollow interior and four legs extending substantially perpendicularly from a plane formed by the frame.

[0017] An electronic device according to a seventh aspect of the present invention is the electronic device according to the sixth aspect of the present invention, characterized in that a hook is provided at the tip of the leg.

[0018] In the present invention, a hook is provided at the tip of the leg. This allows the heat sink held by the holder to be attached to the board by engaging (hooking) the hook into a hole provided in the board. This eliminates the need for additional soldering work to fix the heat sink to the board, and allows the heat sink to be easily attached to the board when assembling the product. Furthermore, if there is a defect in the board, the heat sink can be easily removed.

[0019] An electronic device according to an eighth aspect of the present invention is the electronic device according to the sixth aspect of the present invention, characterized in that a bolt hole is provided at the tip of the leg portion.

[0020] In the present invention, bolt holes are provided at the tips of the legs. This allows the heat sink held by the holder to be attached to the board by inserting bolts through the bolt holes provided at the tips of the legs and the bolt holes provided in the board and fastening the bolts to the metal plate or the like that fastens the board. This eliminates the need for additional soldering work to fasten the heat sink to the board, and allows the heat sink to be easily attached to the board when assembling the product. Furthermore, even if there is a defect in the board, the heat sink can be easily removed.

[0021] The electronic device of a ninth invention is the electronic device of the sixth invention, characterized in that, in the four legs, hooks are provided at two ends, and bolt holes are provided at the two ends.

[0022] An electronic device according to a tenth aspect of the present invention is the electronic device according to any one of the sixth to ninth aspects of the present invention, characterized in that the frame is provided with a positioning portion for positioning the heat sink.

[0023] An electronic device of an eleventh aspect of the present invention is the electronic device of the tenth aspect of the present invention, characterized in that the positioning portion has a substantially semicircular shape and protrudes inwardly of the frame.

[0024] The electronic device of the 12th invention is an electronic device of any of the 1st to 11th inventions, characterized in that the heat sink has a generally rectangular base, a plurality of fins standing vertically from the generally rectangular base to the extension direction of the base, and the bottom provided on the surface opposite the base from the plurality of fins.

[0025] An electronic device according to a thirteenth aspect of the present invention is the electronic device according to the twelfth aspect of the present invention, characterized in that the base is provided with a positioned portion corresponding to a positioning portion provided on the holder. Effect of the Invention

[0026] According to the present invention, it is possible to minimize the increase in cost due to processing of the heat sink, and also to minimize the dead space when fixing the heat sink to the substrate. [Brief description of the drawings]

[0027] [Figure 1] FIG. 2 is a diagram showing an example of a substrate used in the electronic device according to the embodiment of the present invention. [Diagram 2] FIG. 2 is an enlarged view of the heat sink and its surroundings in FIG. [Diagram 3] FIG. [Figure 4] FIG. [Diagram 5] FIG. 4 is a bottom view showing the heat sink and the holder. [Figure 6] FIG. 4 is a cross-sectional view showing a cross section of a heat sink and a holder. [Figure 7] FIG. 2 is a diagram showing a heat sink and a holder mounted on a substrate. [Figure 8] 4 is a cross-sectional view showing a cross section of a heat sink and a holder in a state where the heat sink and the holder are mounted on a substrate. FIG. [Figure 9] 4 is a cross-sectional view showing a cross section of a heat sink and a holder in a state where the heat sink and the holder are mounted on a substrate. FIG. [Figure 10] FIG. 4 is an enlarged cross-sectional view showing the vicinity of the leg portion. [Figure 11] 4 is a cross-sectional view showing a cross section of a heat sink and a holder in a state where the heat sink and the holder are mounted on a substrate. FIG. [Figure 12] 1A and 1B are diagrams showing a conventional structure for attaching a heat sink to a substrate. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] Hereinafter, an embodiment of the present invention will be described. FIG. 1 is a diagram showing an example of a substrate 1 used in an electronic device according to an embodiment of the present invention. FIG. 2 is an enlarged view of the vicinity of a heat sink 2 in FIG. 1. FIG. 3 is a perspective view showing a holder 3. FIG. 4 is a perspective view showing a heat sink 2. FIG. 5 is a bottom view showing the heat sink 2 and the holder 3. FIG. 6 is a cross-sectional view showing a cross section of the heat sink 2 and the holder 3. FIG. 7 is a diagram showing the heat sink 2 and the holder 3 in a state where they are provided on the substrate 1. FIGS. 8, 9, and 11 are cross-sectional views showing a cross section of the heat sink 2 and the holder 3 in a state where they are provided on the substrate 1. FIG. 10 is an enlarged cross-sectional view showing the vicinity of a leg 3d (3e).

[0029] The electronic device is, for example, an AV receiver that is connected to a CD player and a speaker, amplifies an audio signal output from the CD player, and outputs the amplified audio signal to the speaker.

[0030] As shown in the figure, the board 1 is provided with components such as jacks for connecting various ICs and connectors. The board 1 is also provided with a heat sink 2. The heat sink 2 is held by a holder 3. The heat sink 2 is for dissipating heat generated from an IC 4 (component) provided on the board 1. An elastic thermally conductive sheet 5 is provided between the heat sink 2 and the IC 4. In other words, the thermally conductive sheet 5 is sandwiched between the heat sink 2 and the IC 4.

[0031] The holder 3 has a hollow, substantially rectangular frame 3a and four legs 3b to 3e extending substantially perpendicularly from a plane formed by the frame 3a. The four legs 3b to 3e are provided at substantially four corners of the substantially rectangular frame 3a. Hooks 3ba and 3ca are provided at the tips of the legs 3b and 3c provided on one long side of the substantially rectangular frame 3a. Bolt holes 3da and 3ea are provided at the tips of the legs 3d and 3e provided on the other long side of the substantially rectangular frame 3a.

[0032] A positioning portion 3aa is provided on each of the short sides of the substantially rectangular frame 3a. The positioning portion 3aa is substantially semicircular and protrudes inwardly of the frame 3a. The positioning portion 3aa is for positioning the heat sink 2. The positioning portion 3aa is provided in consideration of the extrusion dimensional tolerance of the heat sink 2. A bridge portion 3ab is provided from a position on one long side of the frame 3a where the leg portion 3b is located to the other long side. Similarly, a bridge portion 3ac is provided from a position on one long side of the frame 3a where the leg portion 3c is located to the other long side. Furthermore, a bridge portion 3ad is provided from approximately the center of one long side of the frame 3a to the other long side. The holder 3 is made of, for example, resin. Preferably, the holder 3 is made of polypropylene (PP). Polypropylene is preferable in terms of the relationship between heat and cost.

[0033] The heat sink 2 has a substantially rectangular base 2a, a plurality of fins 2b standing vertically from the substantially rectangular base 2a in the direction in which the base 2a extends, and a protruding portion 2c (bottom) provided on the surface opposite the fins 2b and the base 2a. In this embodiment, 14 fins 2b are provided. Of course, the number of fins 2b is just an example. The protruding portion 2c is substantially frustum shaped. A positioned portion 2aa is provided on each of the short sides of the substantially rectangular base 2a. The positioned portion 2aa is a concave shape corresponding to the positioning portion 3aa provided on the holder 3. The positioned portion 2aa of the heat sink 2 and the positioning portion 3aa of the holder 3 position the heat sink 2 in the holder 3.

[0034] The procedure for attaching the heat sink 2 to the substrate 1 will be described below. The procedure described below is an example. First, the heat sink 2 is inserted into the frame 3a of the holder 3 from the leg portions 3b to 3e side of the holder 3, and the heat sink 2 is attached to the holder 3. At this time, the heat sink 2 is positioned on the holder 3 by the positioned portion 2aa of the heat sink 2 and the positioning portion 3aa of the holder 3. Next, the thermally conductive sheet 5 is placed on the IC 4 provided on the substrate 1. Next, the holder 3 is placed on the substrate 1 so that the protruding portion 2c of the heat sink 2 contacts the thermally conductive sheet 5 on the IC 4. At this time, the hooks 3ba and 3ca of the holder 3 to which the heat sink 2 is attached are inserted into the holes 1a provided in the substrate 1, and the hooks 3ba and 3ca are engaged (hooked) into the holes 1a. Furthermore, bolts 6 are inserted through bolt holes 3da and 3ea of ​​holder 3 and bolt holes (not shown) provided in substrate 1, and the bolts 6 are fixed to sheet metal 7 that fixes substrate 1. In this way, heat sink 2 integrated with holder 3 is attached to substrate 1.

[0035] The holder 3 holds the heat sink 2 so that the protruding portion 2c of the heat sink 2 is exposed. The holder 3 is attached to the substrate 1 so that the protruding portion 2c of the heat sink 2 is positioned above the IC 4.

[0036] As described above, the heat sink 2 is fixed to the substrate 1 by fixing the holder 3 with bolts 6 to the metal plate 7 that fixes the substrate 1, and by engaging (hooking) the hooks 3ba and 3ca on the holder 3 into holes 1a on the substrate 1. Because the holder 3 is made of resin, patterns can be drawn around the holes 1a where the hooks 3ba and 3ca are engaged, without having to worry about short circuits, as is the case with metal. Also, the prohibited area can be made smaller in the area from near the IC to the area connected to other ICs.

[0037] Furthermore, because the heat sink 2 is fixed to the board 1 by the hooks 3ba and 3ca provided on the holder 3 and the bolts 6, no additional soldering work is required, and the heat sink 2 can be fixed to the board 1 when assembling the product. Furthermore, even if a defect occurs in the board 1, the heat sink 2 can be easily removed.

[0038] In addition, an elastic thermally conductive sheet 5 is sandwiched between the heat sink 2 and the IC 4. The heat sink 2 and the holder 3 are designed to compress the thermally conductive sheet 5 to a certain value. For example, the thermally conductive sheet 5 of 1.5 mm is designed to be compressed to 1 mm by the heat sink 2 and the IC 4. When the thermally conductive sheet 5 is compressed, a repulsive force is generated, and the heat sink 2 and the holder 3 are lifted upward. This strengthens the engagement (hooking) of the hooks 3ba and 3ca of the holder 3 with the hole 1a. On the other hand, since the holder 3 is made of resin and has flexibility, excessive pressure on the IC 4 due to the fixation by the holder 3 is reduced.

[0039] In addition, when a heat sink is provided on a high-frequency board, the heat sink may be connected to the ground if there is an effect of radiation, etc. In this case, a clip-shaped leaf spring can be sandwiched between the holder and the heat sink, and the screwed part can be connected to the ground.

[0040] As described above, in this embodiment, the heat sink 2 is attached to the substrate 1 by the holder 3, which minimizes the increase in cost due to processing the heat sink 2. In addition, the holder 3 increases the degree of freedom in design, which minimizes the dead space when the heat sink 2 is fixed to the substrate 1.

[0041] Moreover, in this embodiment, the holder 3 is made of resin (for example, polypropylene). This allows for greater freedom in designing the holder 3. Also, unlike metal, it is possible to draw a pattern on the substrate 1 without having to worry about short circuits. As a result, it is possible to further minimize the dead space when fixing the heat sink 2 to the substrate 1.

[0042] In this embodiment, hooks 3ba and 3ca are provided at the tips of the legs 3b and 3c. This allows the heat sink 2 held by the holder 3 to be attached to the substrate 1 by engaging (hooking) the hooks 3ba and 3ca into holes 1a provided in the substrate 1. This eliminates the need for additional soldering work to fix the heat sink 2 to the substrate 1, and allows the heat sink 2 to be easily attached to the substrate 1 when assembling the product. Furthermore, even if there is a defect in the substrate 1, the heat sink 2 can be easily removed.

[0043] In this embodiment, bolt holes 3da and 3ea are provided at the tips of the legs 3d and 3e. Thus, the heat sink 2 held by the holder 3 can be attached to the board 1 by inserting the bolt 6 through the bolt holes 3da and 3ea provided at the tips of the legs 3d and 3e and through the bolt hole provided in the board 1, and fixing the bolt 6 to the metal plate 7 or the like that fixes the board 1. Therefore, additional soldering work is not required to fix the heat sink 2 to the board 1, and the heat sink 2 can be easily attached to the board 1 when assembling the product. Furthermore, even if there is a defect in the board 1, the heat sink 2 can be easily removed.

[0044] Although an embodiment of the present invention has been described above, the forms to which the present invention can be applied are not limited to the above-described embodiment, and appropriate modifications can be made without departing from the spirit of the present invention. [Industrial Applicability]

[0045] The present invention can be suitably used in electronic devices equipped with a heat sink. [Explanation of symbols]

[0046] 1 Board 2 Heat sink 2a Base 2aa Positioned part 2b Fins 2c Projection (bottom) 3 Holder 3a Frame 3aa Positioning part 3b~3e Legs 3ba, 3ca hook 3da, 3ea bolt holes 4 IC (parts) 5. Thermally conductive sheet 6 Volts 7. Sheet Metal

Claims

1. A substrate; A component provided on the substrate; a heat sink for dissipating heat generated by the component; a holder that holds the heat sink so that a bottom portion of the heat sink is exposed; the holder is mounted on the substrate such that a bottom of the heat sink is positioned on the component; The holder has a generally rectangular frame and four legs extending generally perpendicularly from a plane defined by the frame; The frame has an opening on the inside, The legs are provided with hooks at their tips.

1. An electronic device comprising:

2. 2. The electronic device according to claim 1, wherein the holder is made of resin.

3. 3. The electronic device according to claim 1, wherein the holder is made of polypropylene.

4. 4. The electronic device according to claim 1, further comprising a thermally conductive sheet provided between the component and the heat sink.

5. The electronic device according to claim 4 , wherein the thermally conductive sheet has elasticity.

6. An electronic device as described in any one of claims 1 to 5, wherein the holder has a bridge portion, and the bridge portion is arranged to bridge from one side of a substantially rectangular frame to the other side.

7. 2. The electronic device according to claim 1, wherein a bolt hole is provided at a tip of the leg portion.

8. 2. The electronic device according to claim 1, wherein the four legs each have a hook at one end and a bolt hole at the other end.

9. 9. The electronic device according to claim 1, wherein the frame is provided with a positioning portion for positioning the heat sink.

10. The electronic device according to claim 9 , wherein the positioning portion has a substantially semicircular shape and protrudes inwardly of the frame.

11. The heat sink is A substantially rectangular base; A plurality of fins are provided vertically from the substantially rectangular base in a direction perpendicular to an extension direction of the base; the bottom portion provided on a surface opposite to the plurality of fins and the base; 11. The electronic device according to claim 1, further comprising:

12. 12. The electronic device according to claim 11, wherein the base is provided with a positioned portion that corresponds to a positioning portion provided on the holder.

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