JP2018056484A - Electronic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve shielding against an electromagnetic wave.SOLUTION: An electronic apparatus comprises: a substrate having circuit parts formed on a first surface thereof and a second surface opposite the first surface; and a housing accommodating the substrate and having a first rib surrounding the circuit part on the first surface and a second rib opposite the first rib and surrounding the circuit part on the second surface. The substrate has: a first ground pattern formed on the first surface so as to be in contact with the first rib; a second ground pattern formed on the second surface so as to be in contact with the second rib; and a plurality of vias connecting the first ground pattern and the second ground pattern at a position in contact with a contour when the first ground pattern or the second ground pattern is viewed in a thickness direction.SELECTED DRAWING: Figure 6

Description

  The present invention relates to an electronic device.

  In various types of electronic equipment, a board with circuit portions formed on both sides is often housed in a housing, and it is important to shield electromagnetic waves generated from the board and electromagnetic waves entering the board from outside the housing. is there. For this reason, the structure which isolates the circuit part of both surfaces of a board | substrate electromagnetically is employ | adopted.

  For example, a pair of ribs facing each other and surrounding the circuit portions on both sides of the substrate are provided on the housing, and a ground pattern that contacts the pair of ribs is formed on both sides of the substrate. There is a structure in which a ground pattern is connected by a via while being sandwiched between ribs. In this structure, the circuit portions on both sides of the substrate are isolated by a casing, a pair of ribs provided on the casing, a ground pattern on both sides of the substrate, and vias. As a result, electromagnetic waves generated from the substrate and electromagnetic waves entering the substrate from the outside of the housing are shielded by the housing, the pair of ribs provided on the housing, the grounding patterns on both surfaces of the substrate, and vias.

JP-A-8-330772 Japanese Patent Laid-Open No. 10-200288 Japanese Patent Laid-Open No. 9-18186

  However, when the ground patterns on both sides of the substrate are connected by vias, there is a problem that the shielding property of electromagnetic waves may be lowered.

  That is, when the ground patterns on both sides of the substrate are connected by vias, the vias are generally formed at contact portions between the ground patterns and a pair of ribs provided on the housing. For this reason, each ground pattern is formed with a portion projecting from the via (hereinafter referred to as a “ground pattern projecting portion”) toward the contour line when the ground pattern is viewed from the thickness direction. When a ground pattern protrusion is formed on each ground pattern, the ground pattern protrusion functions as an antenna for electromagnetic waves having a specific wavelength. For this reason, even if the ground patterns on both sides of the substrate are connected by vias, the ground pattern protrusions transmit or receive unintended electromagnetic waves, and as a result, the shielding properties of the electromagnetic waves may be reduced.

  The disclosed technology has been made in view of the above, and an object thereof is to provide an electronic device capable of improving the shielding property of electromagnetic waves.

  An electronic device disclosed in the present application is, in one aspect, a substrate having a circuit portion formed on a first surface and a second surface opposite to the first surface, and a housing that houses the substrate. A housing having a first rib surrounding the circuit portion on the first surface and a second rib facing the first rib and surrounding the circuit portion on the second surface; A first ground pattern formed on the first surface so as to be in contact with one rib, a second ground pattern formed on the second surface so as to be in contact with the second rib, and the first ground pattern or A plurality of vias connecting the first ground pattern and the second ground pattern at a position in contact with the contour line when the second ground pattern is viewed from the thickness direction.

  According to one aspect of the electronic device disclosed in the present application, there is an effect that the shielding property of electromagnetic waves can be improved.

FIG. 1 is a perspective view illustrating an appearance of an electronic apparatus according to the present embodiment. FIG. 2 is an exploded perspective view of the electronic apparatus of the present embodiment. FIG. 3 is a plan view of the upper case as viewed from the substrate side. FIG. 4 is a plan view of the lower case as viewed from the substrate side. FIG. 5 is a plan view of the substrate as viewed from the first surface. FIG. 6 is a cross-sectional view illustrating a state in which the substrate is accommodated in the housing. FIG. 7 is an enlarged cross-sectional view showing a J portion of FIG. FIG. 8 is a plan view when the first ground pattern shown in FIG. 7 is viewed from the thickness direction. FIG. 9 is a diagram for explaining an arrangement mode of the plurality of first vias and the plurality of second vias. FIG. 10 is a diagram for explaining a modification of the arrangement mode of the plurality of first vias and the plurality of second vias.

  Hereinafter, embodiments of an electronic device disclosed in the present application will be described in detail with reference to the drawings. The disclosed technology is not limited by this embodiment.

  FIG. 1 is a perspective view illustrating an appearance of an electronic apparatus according to the present embodiment. FIG. 2 is an exploded perspective view of the electronic apparatus of the present embodiment. As shown in FIGS. 1 and 2, the electronic device 100 of this embodiment includes a substrate 110 and a housing 120.

  A circuit unit 111, connector units 112 and 113, and an antenna unit 114 are formed on the first surface and the second surface of the substrate 110. Here, the first surface and the second surface of the substrate 110 correspond to the front surface and the back surface of the substrate 110. Hereinafter, the surface illustrated in FIG. 2 is referred to as a first surface, and the surface opposite to the surface illustrated in FIG. 2 is referred to as a second surface. In FIG. 2, the circuit unit 111, the connector units 112 and 113, and the antenna unit 114 formed on the first surface of the substrate 110 are shown. However, it is assumed that the circuit portion 111, the connector portions 112 and 113, and the antenna portion 114 are also formed on the second surface of the substrate 110. The circuit unit 111 is an area where various circuits are mounted. The connector portions 112 and 113 are areas where various connectors are mounted. The antenna unit 114 is an area where the antenna is mounted. Details of the substrate 110 will be described later.

  The housing 120 is made of a material having an electromagnetic wave shielding property, and includes an upper case 130 and a lower case 140. The upper case 130 and the lower case 140 are fitted so as to sandwich the substrate 110, whereby the substrate 110 is accommodated in the housing 120. Further, the upper case 130, the lower case 140, and the substrate 110 are fixed by screws 150. A resin cover 131 and a cover 141 are attached to the upper case 130 and the lower case 140, respectively. The antenna unit 114 formed on the first surface and the second surface of the substrate 110 is covered with a cover 131 and a cover 141.

  FIG. 3 is a plan view of the upper case as viewed from the substrate side. FIG. 4 is a plan view of the lower case as viewed from the substrate side. As shown in FIG. 3, the upper case 130 is formed with an upper rib 132 surrounding the circuit portion 111 on the first surface of the substrate 110. On the other hand, as shown in FIG. 4, the lower case 140 is formed with a lower rib 142 that faces the upper rib 132 and surrounds the circuit unit 111 on the second surface of the substrate 110.

  Next, details of the substrate 110 will be described with reference to FIGS. 2 and 5 to 9. FIG. 5 is a plan view of the substrate as viewed from the first surface. FIG. 6 is a cross-sectional view illustrating a state in which the substrate is accommodated in the housing. 6 corresponds to a cross-sectional view taken along the line II of FIG. FIG. 7 is an enlarged cross-sectional view showing a J portion of FIG.

  As shown in FIGS. 2 and 5 to 7, the substrate 110 includes a first ground pattern 115, a second ground pattern 116, and a plurality of vias 117.

  The first ground pattern 115 is formed on the first surface of the substrate 110 so as to contact the upper rib 132 of the upper case 130. The second ground pattern 116 is formed on the second surface of the substrate 110 so as to contact the lower rib 142 of the lower case 140. That is, when the upper case 130 and the lower case 140 are fitted, the first ground pattern 115 and the upper rib 132 are in contact with each other, and the second ground pattern 116 and the lower rib 142 are in contact with each other. Accordingly, as shown in FIGS. 6 and 7, the substrate 110 has an upper rib 132 at a contact portion between the upper rib 132 and the first ground pattern 115 and a contact portion between the lower rib 142 and the second ground pattern 116. And the lower rib 142.

  The plurality of vias 117 penetrate the substrate 110 and connect the first ground pattern 115 and the second ground pattern 116.

  As described above, the plurality of vias 117 are connected to the first ground pattern 115 and the first ground pattern 115 in a state where the substrate 110 is sandwiched between the upper rib 132 and the lower rib 142 via the first ground pattern 115 and the second ground pattern 116. 2 The ground pattern 116 is connected. For this reason, the circuit portion 111 on the first surface and the circuit portion 111 on the second surface of the substrate 110 include a housing 120, an upper rib 132, a lower rib 142, a first ground pattern 115, a second ground pattern 116, and a plurality of Isolated by via 117. As a result, the electromagnetic wave generated from the substrate 110 or the electromagnetic wave entering the substrate 110 from the outside of the housing 120 causes the housing 120, the upper rib 132 and the lower rib 142, the first ground pattern 115, the second ground pattern 116, and the like. Blocked by a plurality of vias 117.

  Here, details of the plurality of vias 117 will be described. FIG. 8 is a plan view when the first ground pattern shown in FIG. 7 is viewed from the thickness direction. In the example shown in FIG. 8, it is assumed that the contour line when the first ground pattern 115 is viewed from the thickness direction and the contour line when the second ground pattern 116 is viewed from the thickness direction are the same. Here, the contour line when the first ground pattern 115 or the second ground pattern 116 is viewed from the thickness direction includes the first contour line O1 and the second contour line O2. The first contour line O1 is a contour line closer to the circuit portion 111 on the first surface of the substrate 110 and the circuit portion 111 on the second surface of the substrate 110 than the upper rib 132 and the lower rib 142. The second contour line O2 is a contour line that exists on the opposite side of the first contour line O1 with respect to the upper rib 132 and the lower rib 142.

  As shown in FIG. 8, the plurality of vias 117 are in contact with the contour line (first contour line O1 or second contour line O2) when the first ground pattern 115 or the second ground pattern 116 is viewed from the thickness direction. , The first ground pattern 115 and the second ground pattern 116 are connected. Specifically, the plurality of vias 117 are contour lines so that the plurality of vias 117 do not overlap the contact portion C between the upper rib 132 or the lower rib 142 and the first ground pattern 115 or the second ground pattern 116. It is formed at a position in contact with (first outline O1 or second outline O2). In the present embodiment, the plurality of vias 117 include a plurality of first vias 117a formed at positions in contact with the first contour line O1, and a plurality of second vias 117b formed at positions in contact with the second contour line O2. Have

  FIG. 9 is a diagram for explaining an arrangement mode of the plurality of first vias and the plurality of second vias. As shown in FIG. 9, the plurality of first vias 117 a and the plurality of second vias 117 b are from contact portions C between the upper rib 132 or the lower rib 142 and the first ground pattern 115 or the second ground pattern 116. Placed at a distance. That is, the distance between the plurality of first vias 117a and the contact portion C and the distance between the plurality of second vias 117b and the contact portion C are both L1.

  In addition, the plurality of first vias 117a are arranged at equal intervals, and the plurality of second vias 117b are arranged at equal intervals. That is, the intervals between the plurality of first vias 117a are all L2, and the intervals between the plurality of second vias 117b are all L2.

  As described above, the plurality of vias 117 connect the first ground pattern 115 and the second ground pattern 116 at a position in contact with the first contour line O1 or the second contour line O2. Therefore, each of the first ground pattern 115 and the second ground pattern 116 is formed with a portion projecting from the plurality of vias 117 toward the first contour line O1 or the second contour line O2, that is, a ground pattern projecting portion. Not. Therefore, a situation where the first ground pattern 115 and the second ground pattern 116 transmit or receive an unintended electromagnetic wave is avoided. As a result, electromagnetic wave shielding properties can be improved.

  As described above, according to the present embodiment, each ground pattern is formed in a state where the substrate is sandwiched between the pair of ribs of the housing via the two ground patterns formed on the first surface and the second surface of the substrate. The two ground patterns are connected by a plurality of vias at a position in contact with the contour line of. Accordingly, the ground pattern protrusion is not formed on each of the two ground patterns formed on the first surface and the second surface of the substrate. For this reason, the situation where the two ground patterns formed on the first surface and the second surface of the substrate transmit or receive unintended electromagnetic waves is avoided. As a result, electromagnetic wave shielding properties can be improved.

  In addition, according to the present embodiment, a plurality of vias are formed at positions in contact with the contour lines of the respective ground patterns so that the plurality of vias do not overlap each contact portion between each rib of the housing and each ground pattern of the substrate. To do. As a result, bumps due to vias are not formed at the contact portions between the ribs of the housing and the ground patterns of the substrate, so that poor contact between the ribs of the housing and the ground patterns of the substrate is avoided. . For this reason, the clearance gap which accept | permits passage of electromagnetic waves is not formed between each rib of a housing | casing, and each grounding pattern of a board | substrate. As a result, the shielding property of electromagnetic waves can be further improved.

  In addition, according to the present embodiment, a plurality of first vias are formed at positions in contact with the first contour lines close to the circuit portions of the first surface and the second surface of the ground pattern among the contour lines of each ground pattern. A plurality of second vias are formed at positions in contact with the second contour line opposite to the first contour line with respect to each rib of the body. Thereby, regarding the space between the two grounding patterns formed on the first surface and the second surface of the substrate, the shielding property of the electromagnetic wave can be further improved.

  Further, according to the present embodiment, the plurality of first vias and the plurality of second vias are arranged at an equal distance from the contact portion between each rib of the housing and each grounding pattern of the substrate, and the plurality of first vias Are arranged at equal intervals, and the plurality of second vias are arranged at equal intervals. As a result, when the ground pattern is formed in the substrate manufacturing stage, the stress distribution inside the plating layer can be equalized and the flatness of the plating surface can be improved. For this reason, the contact between each rib of the housing and each ground pattern of the substrate can be further stabilized.

  In the above embodiment, the plurality of first vias 117a and the plurality of second vias 117b may be arranged in a staggered manner as shown in FIG. FIG. 10 is a diagram for explaining a modification of the arrangement mode of the plurality of first vias and the plurality of second vias. 10, the same parts as those in FIG. 9 are denoted by the same reference numerals.

  As shown in FIG. 10, the plurality of first vias 117a and the plurality of second vias 117b are arranged in a staggered manner with the gaps between the plurality of second vias 117b shielded by the first vias 117a. Is done.

  As described above, by arranging the plurality of first vias 117a and the plurality of second vias 117b in a staggered manner, the electromagnetic wave is related to the gap between the plurality of first vias 117a and the gap between the plurality of second vias 117b. The shielding property can be further improved.

  In addition, the electronic device 100 described in the above embodiment can be disposed on a moving body such as an automobile. In a mobile body such as an automobile, generally, standards relating to electromagnetic interference (EMI) are strict. By arranging the electronic device 100 in such a moving body, electromagnetic waves leaking from the moving body can be suppressed. As a result, the EMI standard is satisfied in the moving body.

100 Electronic device 110 Substrate 111 Circuit portion 115 First ground pattern 116 Second ground pattern 117 Via 117a First via 117b Second via 120 Case 130 Upper case 132 Upper rib 140 Lower case 142 Lower rib 150 Screw

Claims (5)

A substrate having a circuit portion formed on a first surface and a second surface opposite to the first surface;
A housing for accommodating the substrate, comprising: a first rib that surrounds the circuit portion of the first surface; and a second rib that faces the first rib and surrounds the circuit portion of the second surface. A housing,
The substrate is
A first ground pattern formed on the first surface so as to be in contact with the first rib;
A second grounding pattern formed on the second surface so as to contact the second rib;
A plurality of vias connecting the first ground pattern and the second ground pattern at a position in contact with a contour line when the first ground pattern or the second ground pattern is viewed from the thickness direction; Electronic equipment. The plurality of vias are
The plurality of vias are formed at positions in contact with the contour line so as not to overlap a contact portion between the first rib or the second rib and the first ground pattern or the second ground pattern. The electronic device according to claim 1. The contour line includes a first contour line closer to the circuit portion of the first surface and the circuit portion of the second surface than the first rib and the second rib, and the first rib and the second rib. A second contour existing on the opposite side of the first contour as a reference,
The plurality of vias are
A plurality of first vias formed at positions in contact with the first contour line;
The electronic device according to claim 1, further comprising: a plurality of second vias formed at positions in contact with the second contour line. The plurality of first vias and the plurality of second vias are arranged at an equal distance from a contact portion between the first rib or the second rib and the first ground pattern or the second ground pattern,
The plurality of first vias are arranged at equal intervals from each other,
The electronic device according to claim 3, wherein the plurality of second vias are arranged at equal intervals.   The electronic device according to claim 3 or 4, wherein the plurality of first vias and the plurality of second vias are arranged in a staggered manner.

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