JP2011238888A - Electronic apparatus with box type electronic component and heat radiation plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thin electronic apparatus that efficiently conducts heat dissipation of an electronic component while securely shielding an electronic circuit for a tuner from an electromagnetic wave.SOLUTION: A box-type electronic component 0410 is placed on a base substrate 0400. A circuit board 12 is incorporated in a housing 0413 of the box-type electronic component 0410 similarly to the case of the prior art. An electronic circuit consists of an electronic component including an integrated circuit for a tuner 0411 on the circuit board 12. However, unlike the case of the prior art, an upper part of the circuit board 12 is fully or partly opened before a heat radiation plate 0416 is installed to the box-type electronic component 0410 (the opening section 0417 is referred to as "window" hereafter). A heat radiation sheet 0415 is crimped through the window to the upper part of the integrated circuit for the tuner 0411, furthermore, the heat radiation plate 0416 is crimped thereon.

Description

  The present invention relates to a technique for efficiently radiating electronic components while ensuring shielding from electromagnetic waves in an electronic circuit for a tuner and reducing the thickness thereof.

  In recent years, a major issue in household appliances such as televisions and video decks that are being reduced in weight and thickness is the internal temperature of the equipment. When the product is made thinner, the integration of components inevitably progresses. However, the integration of components means that the heat generation source is concentrated, and at the same time, the path for releasing heat to the outside is limited.

  Of the electronic components for which heat dissipation is an issue, special attention must be paid to electronic components for tuners. Tuner electronic components are used to generate clear audio and video signals that are not affected by electromagnetic noise generated by surrounding motors, etc., and at the same time, to prevent leakage of noise generated from tuner electronic components to the outside. It is housed in an aluminum case that can be electromagnetically shielded. However, heat is likely to be trapped inside the case that is shielded from the outside, and heat dissipation becomes a major issue.

  As for electronic components for tuners, various proposals have been made to solve the conflicting problems of electromagnetic shielding and heat dissipation. Patent Document 1 proposes a method of releasing heat by cutting a part of the lid of a metal case and bending it inside the case, and then crimping the tip to the IC chip on the internal substrate. is doing. Patent Document 2 is similar to Patent Document 1 in that the case lid is similarly cut, but a device for making the crimping to the IC chip perfect is made by forming the cut portion in a spring shape. . In Patent Document 3, the tuner electronic circuit is divided into a portion that should give priority to electromagnetic wave shielding and a portion that should give priority to heat radiation, and the former maintains a completely shielded state inside the case, while the latter is external. A method of pressing on a claw formed continuously on a case upper lid while being placed on a substrate exposed to the surface is proposed. Patent Document 4 discloses a method in which a through hole is provided in a circuit board inside a case, a heat radiating sheet is pressure-bonded to an integrated circuit through the through hole, and heat is radiated to the outside by pressing the heat radiating sheet to the case. Has proposed. Patent Document 5 proposes a method of locking a heat sink to a substrate with rivets.

  FIG. 1 is a diagram of a typical example of the prior art when a tuner electronic component is installed on a base substrate. A box-type electronic component 0110 is installed on the base substrate 0100. On the base substrate, in addition to the box-type electronic components, many other electronic components such as an integrated circuit 0101 and a capacitor 0102 are installed. The box-type electronic component is typically an electronic component for a tuner, and a circuit board 0112 is housed inside a housing 0113 that is a box or case of the box-type electronic component. On the circuit board, an electronic circuit is constituted by electronic components including the tuner integrated circuit 0111. The casing is covered with a lid 0114, and the tuner electronic circuit is electromagnetically shielded from the outside. A heat radiating plate 0116 is pressure-bonded to the top of the lid so as to sandwich the heat radiating sheet 0115.

  FIG. 2 is a view showing a state in which a heat sink is pressure-bonded to a tuner electronic component according to a conventional technique. A box-type electronic component 0210 is installed on the base substrate 0200. On the lid 0214 of the box-type electronic component, the heat radiating plate 16 is pressure-bonded so as to sandwich the heat radiating sheet 0215.

  FIG. 3 is a cross-sectional view of the box-type electronic component of FIG. A box-type electronic component 0310 is installed on the base substrate 0300. An electronic substrate 0312 is housed inside a box-type electronic component housing 0313, and tuner integrated circuits 0311 and 0321 are provided on both upper and lower surfaces thereof. On the upper part of the housing, a heat radiating plate 0316 is mounted by pressure with a heat radiating sheet 0315 interposed therebetween. Although not shown in the figure, the heat sink is usually fixed by screwing a foot lowered from the heat sink to the base substrate.

JP-A-10-284650 (FIG. 1) JP 2002-190684 A (FIGS. 1 and 3) JP 2000-216582 (FIG. 1) JP-A-2006-166126 (FIGS. 1 and 6) JP-A-8-88303 (FIG. 1)

  The above-mentioned Patent Documents 1 to 4 all provide a certain solution for the compatibility between electromagnetic wave shielding and heat dissipation in a tuner electronic circuit. However, demands for lightweight and thin electronic devices have become stronger in recent years, and the techniques disclosed in these documents cannot meet the demands. In the prior art example described with reference to FIG. 3, there is a useless gap 0322 between the tuner integrated circuit and the case lid. Further, the thickness of the upper lid 0314 itself of the housing is also an obstacle to thinning. None of the techniques proposed in Patent Documents 1, 2, or 4 can solve these problems. Although there is no such gap in Patent Document 3, it is for an integrated circuit that is less affected by electromagnetic waves, and does not provide a solution for a general tuner electronic circuit. Patent Document 5 does not provide a solution to these problems.

  In addition, it has been stated that the heat sink of FIG. 3 is usually fixed by screwing the feet lowered from the heat sink to the base board. However, in order to secure the screwing portion on the heat sink and the base board, these There is a problem that these parts become larger than necessary.

  In view of such problems, the inventors of the present invention have completed a technique that satisfies the recent demand for light weight and thinness, and at the same time, can achieve both electromagnetic shielding and heat dissipation.

  According to a first aspect of the present invention, there is provided an electronic device comprising a base substrate, a box-type electronic component disposed on the base substrate, and a heat sink, wherein the box-type electronic component includes an electronic circuit. A configured circuit board, a box-shaped housing for housing the circuit board, a window provided on a surface of the housing facing one surface of the circuit board, and heat dissipation disposed on the electronic component disposed on the one surface A sheet, and the heat dissipation plate relates to an electronic device that is pressure-bonded to the heat dissipation sheet via the window.

  According to a second aspect of the present invention, the heat radiating plate is fixed to the base substrate, covers other electronic components disposed on the base substrate, and generates heat generated from the other electronic components. Further, the present invention relates to the electronic device according to claim 1 configured to dissipate heat.

  According to a third aspect of the present invention, in the electronic device according to the second aspect, the heat radiating plate is fixed to the base substrate with a rivet penetrating the box-type electronic component from the base substrate. About.

  According to a fourth aspect of the present invention, the calorific value of the electronic component arranged on the circuit board in the box-type electronic component is the electronic value of the total calorific value of the electronic component arranged on the window side. It is related with the electronic device as described in any one of Claim 1 to 3 larger than the heat_generation | fever total amount of components.

  According to the first aspect of the invention, first, it becomes possible to make the electronic device on which the box-type electronic component is mounted respond to the need for light weight and thinness that is severely approximated. Secondly, the box-type electronic component of the prior art indirectly transfers heat to the heat sink through the case, whereas the box-type electronic component of the first invention passes the heat-dissipating sheet from the component that requires heat dissipation. Because heat is directly transferred to the heat sink, the heat dissipation efficiency is greatly improved. Thirdly, when all the upper parts of the circuit board are opened, the case upper lid can be completely abolished, and the number of parts can be reduced and the work process can be simplified.

    According to the second aspect of the invention, there is provided the electronic device of the first aspect of the invention in which not only the components inside the box-type electronic component but also the other electronic components on the base substrate can be radiated simultaneously with one heat radiating plate.

    According to the 3rd invention, the electronic device of the 2nd invention with which the heat sink was simply and stably fixed is provided.

    According to the fourth invention, the electronic parts of the first to third inventions in which a large number of electronic parts are housed in a small circuit board while ensuring the heat radiation efficiency by arranging electronic parts with a large amount of heat generation on the heat sink side. Equipment is provided.

The figure of the typical example of the prior art in the case of installing the electronic component for tuners in a base board. The figure of the state by which the heat sink was crimped | bonded to the electronic component for tuners by the prior art. Sectional drawing of the box-type electronic component of FIG. The figure showing the procedure which installs a heat sink on a box-type electronic component in Example 1. FIG. The figure of the state by which the heat sink was crimped | bonded to the electronic component for tuners in Example 1. FIG. Sectional drawing around the box-type electronic component of the electronic apparatus of Example 1. FIG. 6 is a diagram illustrating an outline of an electronic apparatus according to a second embodiment. The figure showing the state by which the heat sink was installed in the electronic device of Example 2. FIG. FIG. 10 is a diagram illustrating an outline of an electronic apparatus according to a third embodiment. In the electronic device of Example 3, the figure showing the state by which the heat sink was fixed with the rivet. Sectional drawing centering on the rivet installed in the electronic apparatus of Example 3. FIG.

  Example 1 relates to the first invention. Similarly, Example n (n is an integer of 2 to 4) relates to the nth invention.

<Concept of Example 1>
FIG. 4 is a diagram illustrating a procedure for installing a heat sink on a box-type electronic component in the first embodiment. The arrows in the figure indicate the installation direction of components. This also applies to other drawings in this specification. A box-type electronic component 0410 is installed on the base substrate 0400. A circuit board 0412 is accommodated in the box-type electronic component casing 0413 as in the case of the prior art. On the circuit board, an electronic circuit is constituted by electronic components including the tuner integrated circuit 0411. However, unlike the case of the prior art, in the state before the heat sink is installed, all or part of the upper part of the circuit board is opened in the box-type electronic component (this opening portion 0417 will be referred to as “window” hereinafter). . Through this window, the heat radiating sheet 0415 is pressure-bonded to the upper part of the tuner integrated circuit 0411, and the heat radiating plate 0416 is further pressure-bonded thereon. Note that the casing of the box-type electronic component of Example 1 is formed to be lower than that of the prior art. This is because the space between the lid and the circuit board is not required and the lid itself is unnecessary.

  The upper diagram of FIG. 5 is a diagram showing a state where the heat sink is pressure-bonded to the tuner electronic component in the first embodiment. A box-type electronic component 0510 is installed on the base substrate 0500. A heat radiating plate 0516 is pressure-bonded directly on the tuner integrated circuit of the box-type electronic component with a heat radiating sheet (not shown) interposed therebetween.

  The following figure is a reproduction of the prior art example of FIG. 2 for comparison. The electronic device of Example 1 is significantly thinner than the conventional one. This is because, as already described, in the box-type electronic component of the first embodiment, the space between the lid and the circuit board is unnecessary, and the lid itself is unnecessary.

  6 is a cross-sectional view around the box-type electronic component of the electronic device of the first embodiment. In the left figure, the difference from the prior art explained in FIG. 3 is described. The upper part of the casing 0613 of the box-type electronic component 0610 is open, and directly to the tuner integrated circuit 0611 arranged on the upper surface of the circuit board 0612. A heat radiation sheet 0615 is placed, and a heat radiation plate 0616 is placed thereon. The right figure shows a cross-sectional view of the prior art described in FIG. 3 for comparison. In the electronic apparatus according to the first embodiment, since there is no thickness of the cover of the casing and the space between the cover and the integrated circuit for tuner, it can be seen that the thickness can be reduced as compared with the case of the prior art. .

<Configuration of Example 1>
The configuration of the electronic apparatus according to the first embodiment will be described with reference to FIG. 4 again. The electronic apparatus according to the first embodiment includes a base substrate 0400, a box-type electronic component 0410, and a heat sink 0416. The box-type electronic component includes a circuit board 0412, a housing 0413, a window 0417, and a heat dissipation sheet 0415. Hereinafter, each configuration will be described.

  The “base substrate” is an electronic substrate on which a large number of electronic components including box-type electronic components are mounted, on which various electronic circuits constituted by these electronic components are mounted. In addition to the audio or video receiving circuit realized by the box-type electronic component, for example, a drawing electronic circuit for generating a video signal, an amplifier circuit for generating a speaker, and the like are configured on this base substrate.

  A “box-type electronic component” is an electronic component in which a circuit board is housed in a box-type case. As already described, tuner electronic components are typical, and the purpose of housing them in the case is to shield the internal circuit board from the influence of electromagnetic waves or the like, and to protect components that are vulnerable to vibration from impacts and the like.

  The “heat radiating plate” is a plate for radiating heat generated from an electronic component or the like. In addition to the literal plate shape depicted in Fig. 4 etc., there are a number of folds formed on the surface in order to increase the area for heat dissipation, bent plates, and for the purpose of lightening and thinning. This includes a fan and a water-cooled sink. The material of the heat sink is generally a metal such as iron or aluminum, but other materials having high heat conduction characteristics may be used.

  The “circuit board” is a small board for constituting an electronic circuit such as an electronic circuit for a tuner inside the box-type electronic component. The circuit board is usually a flat plate, and electronic components are arranged on one or both sides thereof.

  The “casing” is a box that is an outer shell of the box-type electronic component, and is configured to be able to store a circuit board therein. The case of FIG. 3 is a box having a rectangular side and bottom, but is not limited to this. However, a shape not suitable for the purpose of thinning is not preferable. As the material for forming the casing, aluminum having high electromagnetic shielding properties and light weight is often used as long as it is an electronic component for a tuner. However, other metals or conductive resins may be used.

  The “window” is an opening formed in the housing, and is used to provide a space for crimping the heat dissipation sheet and the heat dissipation plate on an electronic component such as an integrated circuit for a tuner. In the example of FIG. 4, the entire circuit board is open, but the entire upper part of the circuit board does not need to be exposed for the purpose of crimping a heat-dissipating sheet or the like to an electronic component that requires heat dissipation. A window having a shape in which only an upper part of an electronic component that requires heat radiation is opened may be used. By doing so, the shielding property of electromagnetic waves becomes slightly high. In that case, the portion other than the opening is like a lid with a hole, so that it seems that the effect of thinning by losing the lid is diminished. However, electronic components other than those that require heat dissipation are often small, and even if such a lid is provided, installation is possible while avoiding large electronic components, and there is little obstacle to thinning.

  The “heat dissipating sheet” is installed by crimping between an electronic component that requires heat dissipation and the heat dissipating plate. There are several reasons why heat sinks are not placed directly on electronic components. First, even if hard objects are brought into close contact with each other, they are not brought into close contact with each other, and heat conduction is difficult to be efficiently performed between the electronic component and the heat sink. However, if a soft material is sandwiched between the two, they can be brought into intimate contact with each other to increase thermal conductivity. Secondly, it is necessary to avoid the situation where the shock received by the heat sink is transmitted to the electronic component and damages the electronic component, but if a soft material is sandwiched between the two, the shock received by the heat sink is directly transmitted to the electronic component. It is possible to protect the electronic components from impact. Thirdly, when a plurality of electronic components having different heights are radiated by a single heat radiating plate, the height difference can be adjusted by the thickness of the heat radiating sheet.

  A material for the heat-dissipating sheet is preferably soft, sticky, and high in thermal conductivity. In general, silicon is frequently used. In addition, acrylic or graphite can be used.

  A heat sink is crimped | bonded to the said heat radiating sheet through the said window. There are various methods for fixing the heat sink by pressure bonding. There is a method of fixing by the adhesive force of the heat radiating sheet itself, and a method of using an adhesive for the heat radiating sheet, the heat radiating plate, and the crimping surface of the electronic circuit. When using an adhesive, attention must be paid to the thermal conductivity of the adhesive itself. There is also a method of fixing a screw by dropping a foot from the heat sink onto the base substrate.

  It is preferable to leave a slight gap between the heat sink and the housing of the box-type electronic component. This is because if there is no gap, the heat sink, the heat sink sheet, and the tuner integrated circuit may not be sufficiently bonded. Even if this gap exists, the shielding property of electromagnetic waves is almost the same as that of the prior art. This is because the upper part of the casing is covered with a heat radiating plate having electromagnetic shielding properties, and electromagnetic waves that can enter from the gap are limited.

<Effect of Example 1>
According to the first embodiment, first, it becomes possible to meet the need for a lighter and thinner thickness of an electronic device on which a box-type electronic component is mounted. Secondly, the box-type electronic component of the prior art indirectly transfers heat to the heat dissipation plate through the case, whereas the box-type electronic component of Example 1 passes through the heat dissipation sheet from the component that requires heat dissipation. Because heat is directly transferred to the heat sink, the heat dissipation efficiency is greatly improved. Thirdly, when all the upper parts of the circuit board are opened, the case upper lid can be completely abolished, and the number of parts can be reduced and the work process can be simplified.

<Concept of Example 2>
FIG. 7 is a diagram illustrating an outline of the electronic apparatus according to the second embodiment. In the electronic device of Example 1, the heat sink cooled only the electronic components inside the box-type electronic component. The electronic device according to the second embodiment is characterized in that the heat radiating plate performs not only the electronic components inside the box-type electronic component but also other electronic components that are on the base substrate and need to be radiated. FIG. 8 is a diagram illustrating a state in which a heat sink is installed in the electronic device of the second embodiment.

<Configuration of Example 2>
In the electronic device according to the second embodiment, the heat dissipation plate is fixed to the base substrate, covers other electronic components arranged on the base substrate, and dissipates heat generated from the other electronic components. Configured as follows. The description will be continued with reference to FIG. A box-type electronic component 0710 is installed on the base substrate 0700. Two tuner integrated circuits 0711 that generate heat are installed on a circuit board 0712 inside the box-type electronic component. On the other hand, an integrated circuit 0701 that generates heat is also provided over the base substrate. A heat radiating sheet 0715 is pressure-bonded on top of these integrated circuits, and a heat radiating plate 0716 is further pressure-bonded thereon.

  The heat radiating plate is formed in a shape that covers all electronic components that require heat dissipation. And if it is such, it does not need to be a rectangle as shown in the figure, and should just be large enough to perform heat dissipation. Other characteristics of the heat sink are the same as those of the first embodiment.

<Effect of Example 2>
According to the second embodiment, it is possible to provide an electronic apparatus capable of simultaneously radiating not only the components inside the box-type electronic component but also other electronic components on the base substrate with one heat radiating plate.

<Concept of Example 3>
FIG. 9 is a diagram illustrating an outline of the electronic apparatus according to the third embodiment. In the electronic device of Example 1 or 2, the heat radiating plate was fixed with the adhesive force of the heat radiating sheet, an adhesive, or a screw. The electronic device according to the third embodiment is configured to more easily fix the heat sink using rivets. FIG. 10 is a diagram illustrating a state in which the heat radiating plate is fixed by rivets in the electronic apparatus according to the third embodiment.

<Configuration of Example 3>
The electronic device according to the third embodiment is the electronic device according to the second embodiment in which the heat dissipation plate is fixed to the base substrate with a rivet penetrating the box-type electronic component from the base substrate. This will be specifically described with reference to FIG. A box-type electronic component 0910 is installed on the base substrate 0900, and a circuit board 0912 is accommodated inside the box-type electronic component. A hole 0918 is formed in the circuit board, and although not shown in the drawing, this hole is also formed so as to penetrate through the casing and the base board therebelow. On the other hand, holes 0919 are also formed in the heat sink 0916, and rivets 0920 are attached so as to penetrate these holes. The rivet includes an “shaft” having a diameter slightly smaller than the diameter of the hole and a “head” having a diameter sufficiently larger than the hole formed at one end of the shaft. After the rivet is passed through these holes, it is fixed by sandwiching the heat sink and the base substrate by caulking on the opposite side (in the figure, the back side of the base substrate).

  FIG. 11 is a cross-sectional view centered on a rivet installed in the electronic device of the third embodiment. A box-type electronic component 1110 is installed on the base substrate 1100. A circuit board 1112 is housed inside a box-shaped electronic component casing 1113, and tuner integrated circuits 1111 and 1121 are arranged on both upper and lower surfaces of the circuit board. A heat radiation sheet 1115 is placed on the tuner integrated circuit on the upper side of the circuit board, and a heat radiation plate 1116 is placed thereon. The heat sink, the circuit board, the case, and the base board are perforated, and the rivets 1120 are crimped after passing through the holes, whereby the heat sink, the circuit board, the case, and the base board are It is fixed by crimping so that it is sandwiched between the two heads of the rivet.

  A plurality of rivets may be used, but one is sufficient in the example of FIG. That is, since the heat radiating plate is also supported by the electronic components 0901 and 0911 with the heat radiating sheet 0915 interposed therebetween, if one place is tightened with a rivet, it is stably fixed as a whole.

  There are various rivet head shapes, such as a hemispherical round rivet, a flat conical dish rivet, and a disk-shaped flat rivet. If the purpose of thinning is to be thoroughly achieved, it is preferable to form a groove in the hole of the heat sink so that the head of the rivet is immersed. FIG. 11 shows an example in which such a groove is formed in the heat sink and the base substrate.

  The material of the rivet may be a metal such as aluminum or brass, but a plastic with small magnetism is preferable. In the case of plastic, it is fixed by melting one side with heat or locking the cap.

<Effect of Example 3>
According to the third embodiment, the electronic device of the second embodiment in which the heat sink is simply and stably fixed is provided.

<Concept of Example 4>
The outline of Example 4 will be described using FIG. 11 again. As already described, both sides of the circuit board inside the box-type electronic component are often used to arrange a large number of electronic components by effectively using a small area. The electronic device according to the fourth embodiment is an electronic device that can appropriately dissipate the electronic component by disposing the electronic component having a large heat generation amount on the window side surface of the circuit board. That is, the electronic component 1111 on the upper side of the circuit board 1112 is an electronic component that generates a relatively large amount of heat, and the lower electronic component 1121 is an electronic component that generates a relatively small amount of heat.

<Configuration of Example 4>
In the electronic device according to the fourth embodiment, the heat generation amount of the electronic component disposed on the circuit board in the box-type electronic component is the heat generation amount of the electronic component disposed on the back side of the total heat generation amount of the electronic component disposed on the window side. The electronic device is larger than the total amount. Which electronic component generates more heat can be calculated from the circuit characteristics, and temperature measurement is also possible, so it is easy to determine which electronic component is placed on the window side. The problem is wiring in a small circuit board, which can be realized by forming the wiring inside the board in a three-dimensional structure and forming the wiring in three dimensions.

<Effect of Example 4>
According to the fourth embodiment, a compact electronic device is provided in which a large number of electronic components are housed in a small circuit board while an electronic component with a large amount of heat generation is arranged on the heat dissipation plate side to ensure heat dissipation efficiency.

0400 Base substrate 0410 Box-type electronic component 0411 Tuner integrated circuit 0412 Circuit substrate 0413 Case 0414 Lid 0415 Heat radiation sheet 0416 Heat radiation plate

Claims (4)

A base substrate;
A box-type electronic component disposed on the base substrate;
A heat sink,
An electronic device comprising:
The box-type electronic component is
A circuit board on which an electronic circuit is configured; and
A box-shaped housing for storing circuit boards;
A window provided on the surface of the housing facing one surface of the circuit board;
A heat dissipating sheet disposed on the electronic component disposed on the one surface;
Have
The said heat sink is an electronic device crimped | bonded to the said heat radiating sheet through the said window. The heat dissipation plate is fixed to the base substrate, covers other electronic components disposed on the base substrate, and is configured to dissipate heat generated from the other electronic components. 1. The electronic device according to 1. The electronic apparatus according to claim 2, wherein the heat radiating plate is fixed to the base substrate with a rivet penetrating the box-type electronic component from the base substrate. The calorific value of the electronic component arranged on the circuit board in the box-type electronic component is larger than the total calorific value of the electronic component arranged on the back side of the electronic component arranged on the window side. 4. The electronic device according to any one of 3.