ELECTRONIC CONTROL DEVICE

Abstract

Electronic control device, comprising: an electronic component (104); a metal housing (101) that covers at least part of the electronic component (104); a metal section (105) which is designed such that the electronic component (104) is located between the metal section (105) and the metal housing (101); a shielding structure that shields radiation noise from the electronic component (104) by means of an electrostatic capacitive coupling formed between the metal section (105) and the metal housing (101), wherein the metal section (105) is provided inside a substrate (102) with the electronic component (104) mounted thereon; and a contact section (106) between the substrate (102) and the metal housing (101), wherein the contact section (106) is arranged sandwich-like between the substrate (102) and the metal housing (101) and contacts both the substrate (102) and the metal housing (101), wherein the contact section (106) is covered with a protective lacquer and prevents an electrical connection between the substrate (102) and the metal housing (101), and wherein the contact section (106) extends only in an outer circumference of the substrate (102) and extends along an entire outer circumference of the substrate (102).

Description

Technical area

[0001] The present invention relates to an electronic control device. State of the art

[0002] Inside electronic control devices, there is a circuit board on which a semiconductor device, etc., is mounted. The operating current of the semiconductor device generates unnecessary radiated noise. It is desirable that this radiated noise be as low as possible to avoid adversely affecting other devices. The tolerance level for such radiated noise is standardized by the Comité international spécial des perturbations radioélectriques (CISPRE), a special committee of the International Electrotechnical Commission (IEC), and a specification for radiated noise of component modules mounted on motor vehicles is established for frequencies up to 960 MHz.

[0003] One means of suppressing radiation noise is to use shielding cases to cover printed circuit boards. The abstract of Patent Literature 1 states that "a shielding area 6 is formed by standing surface portions 3 protruding from a surface of a casing 1 and side surfaces 5 of the casing 1, a substrate 7 with electronic components mounted thereon is fixably disposed inside this shielding area 6, a cover 2 covering the top surface of the shielding area 6 is provided to contact the standing surface portions 3 and the side surfaces 5 of the casing 1, and the substrate 7 with electronic components mounted thereon is covered by the standing surface portions 3, the side surfaces 5 of the casing 1, and the cover 2." Furthermore, Patent Literature 2 discloses an electronic device comprising: a printed circuit board; a conductive case; and a connecting part.The printed circuit board is mounted with an electronic component to configure a predetermined electronic circuit. The conductive housing accommodates the printed circuit board. The connector is disposed between the conductive housing and the printed circuit board and is configured to be capacitively coupled to a conductor pattern of the printed circuit board to conduct radiated noise from the printed circuit board to the conductive housing.

[0004] Patent Literature 3 discloses an electromagnetic shielding member including: a shielding portion containing a metal material for sealing an electronic component on an electronic circuit board between the shielding portion itself and the electronic circuit board; a dielectric portion between a conductive portion of the electronic component and the shielding portion, the dielectric portion containing a dielectric material having a relative permittivity of 6 or more; and a laminated portion around the electronic component, the laminated portion being a laminate of the shielding portion and the dielectric portion. Patent Literature 4 discloses an electromagnetic interference (EMI) shielding semiconductor package and a method for manufacturing the same.The semiconductor packages can contain a single electronic component or be a system in a package (SiP). The EMI shield can be applied on top and along the periphery of the semiconductor package. The periphery EMI shield can consist of cured conductive ink or cured conductive paste arranged on the sidewalls of the mold part that encapsulates the electronic component(s) on the semiconductor package. The vertical sections of the EMI shield, including the periphery EMI shield, can be formed by filling conductive ink into trenches created in-situ during the curing of the mold part. The upper part of the EMI shield and the periphery can additionally consist of cured conductive ink.

[0005] Patent Literature 5 discloses a module including a printed circuit board including an insulating layer and one or more copper foil layers embedded in the insulating layer; an electronic component mounted on the printed circuit board; a sealing part that seals the electronic component on the printed circuit board; and a metal film covering the side surfaces of the printed circuit board and the surfaces of the sealing part. A portion of the copper foil is exposed on the side surfaces of the printed circuit board, an exposed portion of the copper foil has a width of less than 200 μm, and the copper foil and the metal film are electrically connected to each other through the exposed portion.

[0006] Patent Literature 6 discloses an electronic control device. Electronic components are mounted on a substrate. A base covers a surface of the substrate. A cover covers a surface of the substrate. A first connector mounted on the surface connects to a connector attached to an on-board transmission. A second connector mounted on the surface connects to a connector of a wire harness. First vibration-damping members provided on the inner side of the base opposite the surface-side end face of the first connector suppress vibration of the first connector.

[0007] Patent Literature 7 shows a printed circuit board. The printed circuit board includes a wiring board, an insert mount with lead terminals, and a flexible insulator. The wiring board has a first surface, a second surface on a side opposite the first surface, and through holes. The insert mount is mounted on the first surface of the printed circuit board such that the lead terminals are inserted into the through holes and soldered to the through holes. At least one of the lead terminals has a distal end protruding from a corresponding one of the through holes. The insulator is provided on the second surface to cover the distal end of the at least one lead terminal.

[0008] Patent Literature 8 shows a semiconductor device including a wiring substrate, a first semiconductor chip mounted on the wiring substrate, a second semiconductor chip mounted on the wiring substrate in a lateral direction thereof, a first irradiation unit connected to the first semiconductor chip and arranged to extend from an upper surface of the first semiconductor chip to an upper surface of the second semiconductor chip, and a second irradiation unit connected to the second semiconductor chip and arranged to extend from a lower surface of the first irradiation unit to an outer surface thereof in a non-contact state to the first irradiation unit. List of referencesPatent literature Patent Literature 1: JP 2001-53482 A Patent literature 2: US 2016 / 0262259 A1 Patent literature 3: US 2015 / 0282394 A1 Patent literature 4: US 2017 / 0179041 A1 Patent literature 5: US 2012 / 0168214 A1 Patent literature 6: US 2018 / 0020558 A1 Patent literature 7: US 2011 / 0155450 A1 Patent literature 8: US 2011 / 0012255 A1 Summary of the inventionTechnical problem

[0009] For an electronic control device intended for use in automobiles, it is necessary to reduce the influence of vibrations such as noise. According to Patent Literature 1, if the casing lacks sufficient strength and processing precision, the casing and cover may warp due to the influence of vibration, and parts of the cover and casing that are close to each other, excluding the bolted part, may collide and generate noise. Therefore, countermeasures such as increasing the strength and processing precision or arranging the casing and cover away from each other are considered so that even if the casing and cover vibrate, collision will not occur at any part other than the bolted part.However, the first countermeasure would increase costs, and the second countermeasure would result in radiation noise from the gaps between the housing and the base.

[0010] The present invention has been made in view of the above-mentioned problems and aims to obtain, in a vehicle control device, a shielding effect against noise radiated from an electronic component. Solution to the problem

[0011] To solve the above problem, the invention is described in the appended claims. Advantageous effects of the invention

[0012] According to the present invention, a shielding effect against noise radiated from an electronic component can be achieved in a vehicle control device. Short description of the drawings Fig. 1 is a cross-sectional view of an electronic control device according to an embodiment of the present invention. Fig. 2 is a plan view of the electronic control device according to an embodiment of the present invention. Fig. 3 is a diagram describing electromagnetic waves emitted from a noise source and currents inside the metal in the electronic control device according to an embodiment of the present invention. Fig. 4 shows, with respect to the electronic control device according to an embodiment of the present invention, experimental results obtained by measuring emission levels with an actual device. Description of embodiments

[0013] An embodiment of the present invention will be described below with reference to the accompanying drawings. The present embodiment relates to an electronic control device used in an automobile, construction machinery, or the like, on which a semiconductor device is mounted.

[0014] Fig. Figure 1 is a cross-sectional view of the electronic control device according to an embodiment of the present invention. The electronic control device is configured to include a metal housing 101 and a substrate 102.

[0015] The substrate 102 has an inner-layer copper foil pattern (metal portion) 105 inside it. Copper foil patterns (not shown) are also present on the surface on both sides of the substrate 102, and a variety of electronic components 103 are deposited and soldered onto these copper foil patterns. The inner-layer copper foil pattern 105 inside the substrate 102 serves as the ground of the electronic control device and has a shape largely similar to the outer shape of the substrate 102, and is formed to cover the entire inner layer. The copper foil patterns on the surface and inside are electrically connected by vias, etc., depending on the desired circuit.

[0016] Meanwhile, aluminum die-casting, with its light weight and high processability, is recommended for the metal case 101. The metal case 101 has a container-like shape and has an attachment portion 107 inside for installing the substrate 102.

[0017] The substrate 102 has solder resist applied to its surfaces. The solder resist was applied during the printed circuit board manufacturing process. The solder resist serves to prevent the solder from adhering to copper foil patterns, which are not contact points where the solder establishes an electrical connection and forms short circuits, during the above-described soldering assembly of the electronic components. At least a contact portion 106 between the substrate 102 and the metal housing 101 is covered by the solder resist, and a width 108 of the solder resist is larger than a contact width 109 between the attachment portion 107 and the substrate 102 at the contact portion 106, thereby preventing an electrical connection between the substrate 102 and the metal housing 101.

[0018] A radiation noise source 104 is a control processor, a large-area integrated circuit (LSI), a field-programmable gate array (FPGA), a memory, a clock line termination resistor, or the like, and generates electromagnetic noise at its periphery when a current with a large rate of change temporarily flows through it. The radiation noise source 104 is installed in a shielding space 110 surrounded by the metal case 101 and the inner-layer copper foil pattern 105 inside the substrate 102, so that the electromagnetic noise cannot escape to the outside. That is, the radiation noise source 104 is arranged facing the bottom of the metal case 101, which has a container-like shape.

[0019] Fig. 2 is a plan view of the electronic control device according to a first embodiment.

[0020] As in Fig. As shown in Fig. 2(a), the substrate 102 is attached to the mounting portion 107 of the metal case 101 after the electronic components 103 are attached by soldering, and is fixed to the metal case 101 with fixing members such as screws 111. The radiation noise source 104 is mounted on the back of the substrate 102 and is located in a position shown in Fig. 2(a) is not visible. Note that the number of screws 110 used for fastening and the fastening positions can be arbitrarily determined, and it is advantageous to reduce the number of screws and fastening positions as much as possible from the perspective of manufacturing costs.

[0021] At Fig. Figure 2(b) is a diagram illustrating the contact portion 106 between the substrate 102 and the metal case 101. As described above with reference to Fig. 1, the side of the substrate 102 is covered with solder mask, preventing electrical connection between the substrate 102 and the metal housing 101. Furthermore, the inner-layer copper foil pattern 105 serves as the ground of the electronic control device and has a shape largely similar to the outer shape of the substrate 102, and is formed so that the entire inner layer is covered.

[0022] At the contact portion 106 between the substrate 102 and the metal case 101, two metal parts, that is, the inner layer copper foil pattern 105 of the substrate 102 and the metal case 101, face each other and form an electrostatic coupling capacitance C satisfying the relationship in the following expression. (Equation 1) C=εS / d

[0023] Here, s is the area of ​​the contact portion 106 between the substrate 102 and the metal housing 101, which in Fig. 2(b). The area s is determined by the width and length of the outer periphery of the contact portion 106. d is the distance between the substrate 102 and the metal case 101. ε is the dielectric constant between the substrate 102 and the metal case 101 and is a fixed value. Therefore, the electrostatic coupling capacitance C formed at the contact portion 106 between the substrate 102 and the metal case 101 is proportional to the area of ​​the contact portion 106 between the substrate 102 and the metal case 101 and is inversely proportional to the distance between the substrate 102 and the metal case 101.

[0024] Fig. 3 is a diagram describing electromagnetic waves radiated from the noise source and currents inside the metal in the electronic control device according to the present embodiment.

[0025] In Fig. 3, when electromagnetic waves 112 are radiated from the radiation noise source 104, a current 113 flows in the surface of the metal shell 101, so that the electromagnetic waves 112 are extinguished. The current 113 flowing in the metal shell 101 is re-radiated at an edge A. When the boundaries A and A' of the metal shell 101 and the substrate 102 are close to each other, the current 113 in the metal shell 101 is re-radiated at the edge A. When the boundaries A and A' of the metal shell 101 and the substrate 102 are close to each other, the current 113 in the metal shell 101 becomes a current 115 flowing in the inner-layer copper foil pattern 105 in the substrate 102 due to the capacitive coupling C, and it becomes possible to prevent radiation to the outside.

[0026] Fig. shows, with respect to the electronic control device according to the present embodiment, experimental results obtained by measuring emission levels using an actual device.

[0027] Fig. Figure 4(b) shows emission levels received by an antenna (not shown) installed on the outside of the electronic control device when the distance d between the substrate 102 with the radiation noise source mounted thereon and the metal housing 101 in Fig. 4(a) was set to 0 mm, 0.5 mm and 1.0 mm. How the emission levels in Fig. 4(b), it was confirmed that in the 1 GHz and 1.46 GHz bands, the coupling capacitance becomes smaller and the emission level increases according to the distance d when the distance between the substrate 102 and the metal case 101 is increased from 0 mm to 0.5 mm and then to 1.0 mm.

[0028] When the metal housing 101 and the substrate 102 are close to each other, the capacitive coupling C at the contact portion 106 can prevent outward radiation. However, the distance d between the substrate 102 and the metal housing 101 is limited because of the fear that the metal housing 101 and the substrate 102 may come into contact due to deformation when vibrations occur. Therefore, to ensure the width of the contact portion 106 and the integrity of the shield, it is desirable that the metal portion 105 and the metal housing 101 face each other over the entire circumference of the outer edge of the substrate 102 without openings.

[0029] Note that, in order to ensure the electrostatic capacity of the contact portion 106 between the substrate 102 and the metal case 101, it is desirable that there be no through-hole / surface pattern in / on the substrate 102 at the contact portion 106. Furthermore, the radiation noise source 104 is a control processor, a memory, a termination resistor of a clock line, a communication circuit, or a power supply circuit, and it is desirable that they be mounted on the surface opposite to a mounting surface of a resin connector.

[0030] The above-described embodiment includes, for example, a metal case 101; a substrate 102; a radiation noise source 104; a metal portion (inner-layer copper foil pattern) 105 provided inside the substrate 102; a contact portion 106 between the substrate 102 and the metal case 101; and a shielding space 110.

[0031] The radiation noise source 104 is mounted on the substrate 102, and the surface on which the radiation noise source 104 is mounted is covered by the metal housing 101. The radiation noise source 104 is arranged inside the shielding space 110 formed by the metal housing 101 and the metal portion 105 provided in the substrate 102. The metal portion 105 and the metal housing 101 are coupled by electrostatic capacitance at the contact portion 106 between the substrate 102 and the metal housing 101.

[0032] Furthermore, the metal portion 105 and the metal housing 101 face each other at least at the outer peripheral edge of the substrate 102 and are coupled by an electrostatic capacitance determined by the width and the outer peripheral length of the contact portion 106 to form the shielding space 110.

[0033] It should be noted that, in view of the integrity of the shield, it is desirable that the contact portion 106 faces the substrate 102 over the entire circumference of the outer edge of the substrate 102 without openings, that is, it is desirable that the contact portion 106 is closed.

[0034] The metal portion 105 may be formed from a copper foil pattern provided inside the substrate 102, and may be a ground or power source of an electronic control device located at an inner layer or surface layer of the substrate 102 and having a large area.

[0035] To ensure the electrostatic capacitance at the contact portion 106 between the substrate 102 and the metal case 101, it is desirable that no through-hole / surface pattern be present in / on the substrate 102 at the contact portion 106. Furthermore, the radiation noise source 104 is a control processor, an LSI, an FPGA, a memory, a clock line termination resistor, a communication circuit, or a power supply circuit, and it is preferable that it be mounted on the surface opposite to a mounting surface of a resin connector.

[0036] According to the above-described embodiment, a shielding effect against noise radiated from an electronic component can be achieved in a vehicle control device. Furthermore, in addition to the shielding effect, a housing structure and mounting method can be realized that also realize a cost reduction for a contact portion between components that forms the shielding surface. List of reference symbols 101 metal housing 102 Substrat 103 electronic components 104 Radiation noise source 105 inner layer copper foil pattern (metal section) 106 Contact section 107 Attachment section 108 Width of the solder mask 109 Width of the substrate contact 110 Shielding Room 111 screws 112 radiated electromagnetic waves 113 Noise current in the metal housing 114 re-radiated electromagnetic field 115 Noise current in the inner layer of the copper foil pattern

Claims

[1] Electronic control device comprising: an electronic component (104); a metal housing (101) covering at least part of the electronic component (104); a metal portion (105) provided such that the electronic component (104) is located between the metal portion (105) and the metal housing (101); a shielding structure that shields radiation noise from the electronic component (104) by an electrostatic capacitive coupling formed between the metal portion (105) and the metal housing (101), wherein the metal portion (105) is provided inside a substrate (102) having the electronic component (104) mounted thereon; and a contact portion (106) between the substrate (102) and the metal housing (101), wherein the contact portion (106) is sandwiched between the substrate (102) and the metal housing (101) and contacts both the substrate (102) and the metal housing (101), wherein the contact portion (106) is covered with a protective varnish and prevents electrical connection between the substrate (102) and the metal housing (101), and wherein the contact portion (106) extends only in an outer periphery of the substrate (102) and extends along an entire outer periphery of the substrate (102). [2] The electronic control device according to claim 1, wherein the metal portion (105) and the metal housing (101) face each other via an insulator of the substrate (102) having the electronic component (104) mounted thereon. [3] The electronic control device according to claim 1, wherein the metal portion (105) is located on an outer periphery of the substrate (102) on which the electronic component (104) is mounted, and the metal portion (105) faces the metal case (101) over the entire outer periphery of the substrate (102). [4] The electronic control device according to claim 1, wherein the metal portion (105) and the metal case (101) are coupled by an electrostatic capacitance depending on a width and an outer circumferential length over which the metal portion (105) and the metal case (101) face each other to form a shielding space that covers the radiation noise. [5] The electronic control device according to claim 4, wherein the metal portion (105) and the metal case (101) are configured so that the shielding space is closed. [6] The electronic control device according to claim 1, wherein the metal portion (105) is a copper foil pattern provided inside the substrate (102) and connected to a ground or a power source, or is a ground or a power source. [7] The electronic control device according to claim 6, wherein the copper foil pattern is formed in an inner layer of the substrate (102). [8] The electronic control device according to claim 6, wherein the copper foil pattern is located on an outer periphery of the substrate (102). [9] The electronic control device according to claim 1, wherein a source of radiation noise is mounted on a surface opposite to a resin connector mounted on the substrate (102). [10] The electronic control device according to claim 1, wherein a source of the radiation noise is a control processor, a memory, a termination resistor of a clock line, a communication circuit, or a power supply circuit.

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