JP2013012582A - Circuit board shield structure and electronic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To protect a circuit board, and an integrated circuit and an electric component mounted on the circuit board, when external force is added, while shielding a plurality of shield target areas on the circuit board.SOLUTION: A circuit board shield structure 7 includes: a circuit board 1 having on one surface a plurality of shield target areas R1-R6 mutually positioned in separation; and a plurality of shield bodies S1-S6, disposed on one surface 4 of the circuit board 1, for covering the respective corresponding shield target areas R1-R6. The plurality of shield bodies S1-S6 are positioned in such a manner that grooves D, E extending between the plurality of shield bodies S1-S6 do not traverse the circuit board 1 linearly.

Description

  The present invention relates to a substrate shielding structure and an electronic apparatus, and more particularly to the configuration and arrangement of a shielding body provided on a substrate.

  Electronic devices such as portable terminals are often provided with an electromagnetic shield for the purpose of preventing the radiation of electromagnetic waves to other components in the electronic device or for preventing the effects of electromagnetic waves from other components. .

  Patent Document 1 discloses a technique in which a substrate is divided into several shielding target areas and each shielding target area is covered with a dedicated shielding body. Specifically, a plurality of metal frames are installed on the substrate so as to be separated from each other, and a common cover (top plate) is attached thereon, and is shielded for each shielding target area.

  Such a shielding body has an effect of increasing the strength of the substrate and preventing the deformation of the substrate. That is, recent electronic devices typified by portable terminals have various functions added, and there is a tendency for integrated circuits and electrical components such as resistors and capacitors to increase. As the display screen and the battery pack increase in size, the total weight of the entire electronic device tends to increase. However, in order to meet the demands of many end users, electronic devices are directed to thinning. Although a display portion such as a liquid crystal panel can be reinforced with tempered glass or the like, a substrate on which an integrated circuit and an electrical component are mounted is likely to receive an impact force due to dropping or the like as the substrate is thinned. When receiving such an impact force, the integrated circuit and the electrical component may be peeled off from the substrate. Even if the peeling does not occur, a crack may occur in the integrated circuit and the electrical component itself, or a crack may occur in the solder for mounting the integrated circuit and the electrical component on the substrate. In the worst case, the substrate itself may be damaged by a crack. Since the shielding body such as a metal shield provided on the substrate increases the strength of the substrate and prevents deformation, it is effective in preventing such a problem.

JP 2001-160698 A

  In the technique described in Patent Document 1, a rectangular parallelepiped shielding body is regularly arranged. Therefore, a linear groove section that crosses the substrate is formed between adjacent shielding bodies. Since the groove portion is not reinforced by the shielding body, the strength is relatively weak and easily deformed as compared with the portion reinforced by the shielding body of the substrate. That is, the portion reinforced by the shielding body of the substrate does not generate a large stress or deformation even when an external force is applied, but a large force is concentrated on the groove portion, the strength of the entire substrate is lowered, and a large deformation occurs. As the substrate is deformed, integrated circuits and electrical components mounted on the substrate are also easily damaged.

  It is an object of the present invention to provide a substrate shielding structure that can easily protect a substrate, an integrated circuit mounted on the substrate, and an electrical component when an external force is applied while shielding a plurality of shielding target areas on the substrate. Objective.

  In the substrate shielding structure of the present invention, a plurality of shielding target regions are provided on one surface and spaced apart from each other, and a plurality of shielding target regions are provided on one surface of the substrate, each covering a corresponding shielding target region. And a shielding body. The plurality of shielding bodies are positioned such that a groove extending between the plurality of shielding bodies does not cross the substrate in a straight line.

  According to the present invention, the groove extending between the shielding bodies does not cross the substrate linearly. For this reason, when an external force is applied, it is difficult for stress to concentrate on a specific part of the substrate. Since the strength of the entire substrate is improved and deformation is suppressed, the substrate can be easily protected, and the integrated circuit and electrical components mounted on the substrate can be easily protected.

  According to the present invention, there is provided a substrate shielding structure that can easily protect a substrate, an integrated circuit mounted on the substrate, and an electrical component when an external force is applied while shielding a plurality of shielding target regions on the substrate. be able to.

It is a fragmentary perspective view of the board | substrate used for an electronic device. It is a top view of the board | substrate shown in FIG. It is a top view of the board | substrate of a prior art.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The substrate shielding structure 7 of the present invention can be applied to an arbitrary electronic device such as a mobile phone device, a mobile terminal such as a smartphone, a tablet personal computer, and a game device, and in particular, an impact load due to a drop, a collision or the like. The present invention can be suitably applied to portable electronic devices that are highly likely to be received.

  FIG. 1 is a partial perspective view of a substrate used in an electronic device, and FIG. 2 is a plan view of the substrate. FIG. 1 shows only a part of FIG. The illustrated substrate 1 is a printed wiring board incorporated in a mobile terminal. The substrate 1 of the present embodiment is rectangular (see FIG. 2), but the shape is not particularly limited, and includes triangles, quadrilaterals other than rectangles, and polygons that are pentagons or more (including polygons formed by combining several rectangles). As described later, a part may have a notch, and a part may have a curved shape.

  As shown in FIG. 1, a large number of integrated circuits 2 and electrical components 3 such as resistors and capacitors connected to the integrated circuits 2 are mounted on a substrate 1. The integrated circuit 2 and the electrical component 3 are mounted on the front surface 4 of the substrate 1 by solder (not shown), and the integrated circuit 2 and the electrical component 3 that are mounted are mounted on the surface of the substrate 1. 4 or copper wiring (not shown) printed inside is electrically connected.

  As shown in FIG. 2, the integrated circuit 2 and the electrical component 3 mounted on the substrate 1 are divided into several groups (shielding target regions R1 to R6) for each shielding target. Each group usually includes, but is not limited to, an integrated circuit 2 and a plurality of electrical components 3 arranged around the integrated circuit 2, and the integrated circuit 2 alone forms one group. It is also possible to form a group with only the electric component 3. One group may include two or more integrated circuits 2. As a result, on the surface 4 of the substrate 1, a plurality of shielding target areas R1 to R6 indicated by broken lines in FIG.

  A plurality of shielding bodies S1 to S6 are provided on the substrate 1. Each shielding body S <b> 1 to S <b> 6 covers the corresponding shielding target region R <b> 1 to R <b> 6, and an internal space 5 is formed between the surface 4 of the substrate 1 to surround the integrated circuit 2 and the electrical component 3. The shielding bodies S1 to S6 are made of metal in order to ensure shielding performance. However, as long as electromagnetic waves can be shielded appropriately, any material such as a metal film formed on the surface of the resin core material should be used. Can do. The substrate 1 and the shielding bodies S1 to S6 constitute a substrate shielding structure 7.

  Each of the shielding bodies S1 to S6 has a top plate 6 and a side wall 8, and has a box-like shape with one surface opened as a whole. Such shielding bodies S1 to S6 can be formed by bending a metal plate into a box shape. In another embodiment, the shielding bodies S1 to S6 have a curved top plate and have a bowl-like overall shape.

  The shielding bodies S <b> 1 to S <b> 6 are fixed to the substrate 1 so that the end portion 9 of the side wall 8 on the side opposite to the top plate 6 contacts the substrate 1. The shape of the shielding bodies S1 to S6 differs depending on the shape and size of the shielding target regions R1 to R6, that is, the number and arrangement of the integrated circuits 2 and the electrical components 3 included in the shielding target regions R1 to R6. In this embodiment, the contact part 10 with the board | substrate 1 of shielding body S1-S6 is formed as a polygonal closed line other than a rectangle. In another embodiment, the contact portion of the part of the shielding body with the substrate 1 is a polygonal closed line other than the rectangular shape, and the contact portion of the other shielding body with the substrate 1 is a rectangular closed shape. It is formed as a line. In still another embodiment, the contact portion of the part or all of the shielding body with the substrate 1 is formed as a closed line having an arbitrary curved shape or a combination of a curved line and a straight line. Examples of such closed lines are squares, rectangles, trapezoids, rhombuses, other quadrilaterals, pentagonal shapes obtained by diagonally cutting corners of rectangles, and two corners of rectangles being diagonally cut Examples of the hexagonal shape, circular shape, semicircular shape, and fan shape that can be obtained. Although the contact part 10 with the board | substrate 1 of shielding body S1-S6 corresponds with the shape of the outer edge of the top plate 6 in this embodiment, you may differ.

  Referring to FIG. 2, in this embodiment, six shielding bodies S <b> 1 to S <b> 6 are provided on the substrate 1. These shielding bodies S1 to S6 have different shapes. Referring to FIG. 1, a seventh shielding body S <b> 7 is provided on the back surface 11 of the substrate 1. The seventh shielding body S7 is a metal shield member, and is indicated by a thick broken line in FIG.

  Semicircular cutouts 12a and 12b for screwing the substrate 1 to a housing (not shown) are formed on two opposite sides of the substrate 1. The shape and number of the notches are not limited, and for example, three or more notches may be provided at the edge of the substrate 1.

  By covering the integrated circuit 2 and the electrical component 3 included in each shielding target area R1 to R6 with the corresponding shielding bodies S1 to S6, each shielding target area R1 to R6 shields the other shielding target areas R1 to R6. Is done. That is, unnecessary electromagnetic waves are prevented from being emitted from the shielding target areas R1 to R6 to the surroundings, and the shielding target areas R1 to R6 are prevented from receiving unnecessary electromagnetic radiation from the surroundings.

  The shielding bodies S1 to S6 also have a function of increasing the strength of the substrate 1 and preventing the deformation of the substrate 1. This makes it difficult for the integrated circuit 2 and the electrical component 3 to be peeled off from the substrate 1 and increases the strength of the substrate 1 itself.

  This embodiment will be further described in comparison with the prior art.

  FIG. 3 is a plan view similar to FIG. 2 showing an example of the shielding structure of the substrate 1 according to the prior art. The shielding target areas R1 to R6 are the same as those in FIG. As in the present embodiment, six shielding bodies S1 'to S6' are provided on the substrate 1, and these shielding bodies S1 'to S6' are all rectangular parallelepiped shapes. No shielding body is provided on the back surface 11 of the substrate 1. The first shielding body S1 'and the second shielding body S2' have the same shape and size and are located opposite to each other. The third to sixth shielding bodies S3 'to S6' are different from each other in shape and size. Between the first and second shields S1 ′ and S2 ′ and the third to fifth shields S3 ′ to S5 ′, there is a groove A on the substrate 1 that crosses the substrate 1 left and right. ing. Since the groove portion A is not reinforced by the shielding bodies S1 'to S6', it is susceptible to tensile stress, bending stress, and the like. For example, when an impact force is applied to the substrate 1 due to an impact such as a drop, there is a high possibility that the substrate 1 will be damaged along the groove A, such as bending or tearing. When the integrated circuit 2 and the electrical component 3 are mounted at a position across the groove A on the back surface 11 of the substrate 1, cracks are generated in the integrated circuit 2 and the electrical component 3, or cracks are generated in the solder that fixes them. There is a high possibility that the integrated circuit 2 and the electrical component 3 will eventually peel off or drop off from the substrate 1. When the substrate 1 undergoes a large deformation, there is a possibility that the printed wiring that extends on or in the substrate 1 is disconnected or damaged.

  Similarly, a groove B exists on the substrate 1. Unlike the groove part A, the groove part B does not cross the substrate 1, but extends on the substrate 1 over a length of approximately three-quarters of the vertical dimension of the substrate 1. Therefore, large tensile stress, bending stress, etc. are likely to occur along the groove B. The groove portion C extends over the substrate 1 over the length of about three-quarters of the lateral dimension of the substrate 1, and the extension line of the groove portion C passes through the two notches 12a and 12b. Since the lines passing through the notches 12a and 12b tend to concentrate bending stress and the like, the groove C is particularly susceptible to damage.

  On the other hand, in the embodiment shown in FIG. 2, the shielding bodies S1 to S6 are configured such that the groove portions extending between these shielding bodies S1 to S6 (representing the groove portions D and E as a representative) form the substrate 1 in a straight line shape. Located so as not to cross over. The groove portion means a space formed as a gap (valley) between the shielding bodies, and a space without the shielding body on both sides is not a groove portion. Therefore, the non-installed area of the shielding bodies S1 to S6 along the peripheral edge of the substrate 1 does not correspond to the groove. Further, “crossing” means that a groove or an extension line thereof extends so as to intersect two different sides of a polygonal substrate, and typically intersects two opposite sides of a rectangular substrate. Means to extend.

  In the example of FIG. 2, there is no groove corresponding to the groove portion A. Therefore, stress and deformation are dispersed and damage to the substrate 1 is less likely to occur. Furthermore, the length of any groove (for example, groove D) is half the distance between two intersections (for example, points 13a and 13b) between the straight line (for example, line L) passing through the center line of the groove and the edge of the substrate 1. It is as follows. In particular, there is no groove on a straight line passing through the two notches 12a and 12b. Even if a groove portion exists on a straight line passing through the two notches 12a and 12b, the length of the groove portion is equal to the straight line passing through the center line of the groove portion and the edge portion of the substrate 1 (in this case, the edge portion of the substrate 1 is It is desirable that the distance is less than half of the distance between two intersections with the notch edge.

  Thus, in the present embodiment, there is no groove portion that linearly crosses the substrate 1, and the length of the existing groove portion is also half of the length when it is assumed that the groove portion has crossed the substrate 1. It is as follows. Such an arrangement of the grooves can be realized by combining the shielding bodies S1 to S6 in which the contact portion 10 with the substrate 1 is rectangular, but the shape of the contact portion 10 with the substrate 1 of the shielding bodies S1 to S6. By making other than rectangular, it can be realized more easily. That is, since the shielding target regions R1 to R6 depend on the layout of the integrated circuit or the like, when the shape of the contact part 10 of all the shielding bodies S1 to S6 with the substrate 1 is rectangular, the shielding bodies S1 to S6 The degree of freedom of arrangement is restricted, and a long linear groove portion is likely to occur. On the other hand, when the contact part 10 with the board | substrate 1 of the shielding bodies S1-S6 is various shapes other than a rectangle, it is hard to be influenced by layouts, such as an integrated circuit, and adjusts the length of each groove part easily. it can.

  Further, a large shield S7 made of a metal shield is disposed on the back surface 11 of the substrate 1. This shielding body S7 covers a wide area of the back surface 11 of the substrate 1 and increases the rigidity of the entire substrate 1. The shield S7 has a substantially rectangular parallelepiped shape, and the contact portion 10 with the substrate 1 is rectangular, but the contact portion 10 can take any shape such as a polygon. Installation of the shielding body S7 is arbitrary. For example, when the weight of the mobile terminal on which the substrate 1 is mounted is extremely light and the impact at the time of dropping is small, the stress is also small, so the shielding body S7 on the back surface 11 of the substrate 1 is small. Can be omitted.

  As described above, in this embodiment, when an electronic device receives an impact force such as a drop or a collision, the force applied to the substrate is dispersed throughout the substrate, thereby suppressing stress concentration and excessive deformation. Can do. Since stress concentration and excessive deformation do not occur in the substrate, it is possible to prevent damage to the substrate itself, damage to the integrated circuit and electrical components, peeling, and dropping off. Furthermore, disconnection of printed wiring can be prevented.

DESCRIPTION OF SYMBOLS 1 Board | substrate 2 Integrated circuit 3 Electrical component 7 Shielding structure of board | substrate 10 Contact part A-E Groove part R1-R6 Shielding object area | region S1-S7 Shielding body

Claims (6)

A substrate in which a plurality of shielding target areas are spaced apart from each other on one surface;
A plurality of shielding bodies provided on the one surface of the substrate, each covering the shielding target area corresponding thereto;
Have
The substrate shielding structure, wherein the plurality of shielding bodies are positioned such that grooves extending between the plurality of shielding bodies do not cross the substrate linearly.   2. The groove according to claim 1, wherein the groove extends in a straight line on the substrate with a length equal to or less than half of a distance between two intersections between a straight line passing through a center line of the groove and an edge of the substrate. The substrate shielding structure described. The substrate has two or more notches at different positions on the outer periphery,
The substrate shielding structure according to claim 2, wherein the groove extends on a straight line passing through any two of the notches.   4. The substrate shielding structure according to claim 1, wherein at least a part of the shielding body in contact with the substrate is formed as a polygonal closed line other than a rectangle. 5. .   The board | substrate shielding structure of any one of Claim 1 to 4 which has another shielding body on the other surface of the said board | substrate.   An electronic device having the substrate shielding structure according to claim 1.

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