Electronic device

Abstract

To obtain an electronic device which enables improvement of electromagnetic noise resistance of the electronic device even when an electronic element exists in an area where electronic components are mounted in high density.SOLUTION: An electronic device 110 includes: a housing 1; a printed wiring board 2 which is a substrate provided in the housing 1; a connector 3 serving as a noise entry part provided in the housing 1; an electronic element 4 serving as a noise affected part provided at the printed wiring board 2; ground wiring 61 serving as a ground provided at the printed wiring board 2; and a linear conductor 7 which is provided between the connector 3 and the electronic element 4 and connected to the ground wiring 61.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present disclosure relates to electronic devices. [Background technology]

[0002] External electromagnetic noise generated from noise sources outside an electronic device may combine with electronic elements and wiring that constitute an electronic circuit, causing the electronic device to malfunction. In recent years, electronic devices have become more densely packed with electronic components and have lower driving voltages, which has reduced the resistance of electronic devices to electromagnetic noise.

[0003] A typical method for improving the electromagnetic noise resistance of electronic devices is to use an electromagnetic shield to cover an electromagnetic noise source with an electromagnetic shield case. By covering an electromagnetic noise source with an electromagnetic shield case, it is possible to prevent electromagnetic noise emitted from the electromagnetic noise source from leaking to the outside (for example, see Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2002-368481 A Summary of the Invention [Problem to be solved by the invention]

[0005] Electromagnetic shielding is a method of blocking spatial conduction of electromagnetic noise in the air by surrounding an object with an electromagnetic shield case made of a conductive material. In Patent Document 1, in order to shield electromagnetic noise emitted from an electromagnetic noise source inside an electronic device, an electromagnetic shield case is provided to surround an electronic element that is an electromagnetic noise source. Meanwhile, the electronic element is not only an electromagnetic noise source but also a noise-affected part. A noise-affected part is an element, among the components of an electronic device, whose voltage fluctuates due to external electromagnetic noise. Therefore, by providing an electromagnetic shield case to surround an electronic element that is also a noise-affected part, the electromagnetic noise resistance of the electronic device against external electromagnetic noise can be improved.

[0006] However, in order to improve the electromagnetic noise resistance of electronic devices against external electromagnetic noise by using an electromagnetic shield, it is necessary to ensure a mounting area for the electromagnetic shield case near the electronic element, which is the noise-affected part. In other words, if the electronic element is located in an area where electronic components are densely mounted, there is a problem that the electromagnetic shield cannot improve the electromagnetic noise resistance of the electronic device.

[0007] The present disclosure has been made to solve the problems described above, and aims to provide an electronic device that can improve the electromagnetic noise resistance of the electronic device even when an electronic element is present in an area where electronic components are densely packed. [Means for solving the problem]

[0008] The electronic device according to the present disclosure comprises a housing, a substrate provided inside the housing, a noise intrusion section provided in the housing where noise intrudes from the outside of the housing into the inside of the housing, an electronic element provided on the substrate and whose voltage fluctuates due to noise intruding through the noise intrusion section, and a linear conductor provided between the noise intrusion section and the electronic element and connected to ground. Effect of the Invention

[0009] According to the electronic device according to the present disclosure, even when an electronic element is present in an area where electronic components are densely mounted, the electromagnetic noise resistance of the electronic device can be improved. [Brief description of the drawings]

[0010] [Figure 1] 1 is a top view showing an electronic device according to a first embodiment of the present disclosure. [Diagram 2] 1 is a cross-sectional view showing an electronic device according to a first embodiment of the present disclosure. [Diagram 3] FIG. 2 is a block diagram showing an example of a circuit configuration of an electronic device according to each embodiment of the present disclosure. [Figure 4] 1 is a top view illustrating components of the electronic device according to a first embodiment of the present disclosure, excluding a housing. [Diagram 5] 1 is a perspective view showing components excluding a housing of an electronic device according to a first embodiment of the present disclosure. [Figure 6] 1 is a side view illustrating components excluding a housing of the electronic device according to a first embodiment of the present disclosure. [Figure 7] 4 is a cross-sectional view showing another example of the electronic device according to the first embodiment of the present disclosure. FIG. [Figure 8] 1 is a perspective view showing components, excluding a housing, of an electronic device according to a first modification of the first embodiment of the present disclosure. FIG. [Figure 9] 11 is a cross-sectional view showing components excluding a housing of an electronic device according to a second modification of the first embodiment of the present disclosure. FIG. [Figure 10] 11 is a perspective view showing components, excluding the housing, of an electronic device according to a third modification of the first embodiment of the present disclosure. FIG. [Figure 11] FIG. 11 is a perspective view showing components excluding a housing of an electronic device according to a second embodiment of the present disclosure. [Figure 12] FIG. 11 is a top view illustrating components excluding a housing of an electronic device according to a second embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] An example of an electronic device according to the present disclosure will be described below with reference to the drawings. In the following drawings, the same or corresponding parts are designated by the same reference numerals, and the description thereof will not be repeated.

[0012] Embodiment 1 As an example of an electronic device according to the first embodiment of the present disclosure, an electronic device 110 called a PLC (Programmable Logic Controller) will be described. An input device (not shown) and an output device (not shown) are electrically connected to the electronic device 110. The electronic device 110 has a function of processing signals from the input device and electronically controlling the output device.

[0013] <Configuration of Electronic Device of First Embodiment> The configuration of electronic device 110 according to embodiment 1 of the present disclosure will be described with reference to Fig. 1 and Fig. 2. Fig. 1 is a top view of electronic device 110. In Fig. 1, components provided inside the housing of electronic device 110 are indicated by dashed lines. Fig. 2 is a cross-sectional view of electronic device 110 taken along line II shown in Fig. 1.

[0014] As shown in Figures 1 and 2, electronic device 110 includes a housing 1, a printed wiring board 2 which is a substrate provided inside housing 1, a connector 3 which is a noise intrusion portion provided in housing 1, an electronic element 4 which is a noise-receiving portion provided on printed wiring board 2, a ground wiring 61 which is a ground provided on printed wiring board 2, and a linear conductor 7 which is provided between connector 3 and electronic element 4 and is connected to ground wiring 61.

[0015] Here, the noise intrusion part is a place where noise intrudes from the outside of the housing 1 into the inside of the housing 1. Moreover, the noise-affected part is an element, among the components of the electronic device 110, whose voltage fluctuates due to noise intruding from the noise intrusion part.

[0016] 1 and 2, the housing 1 covers the printed wiring board 2, a part of the connector 3, the electronic element 4, the ground wiring 61, and the conductor 7. The housing 1 has an opening 11 for installing the connector 3. The housing 1 is made of, for example, a metal material such as steel or aluminum, or a resin material such as ABS resin or polycarbonate (PC) resin.

[0017] The printed wiring board 2 is formed of, for example, glass fiber reinforced epoxy resin, phenolic resin, polyphenylene sulfide (PPS), polyether ether ketone (PEEK), or the like. The printed wiring board 2 may also be formed of a material generally considered to have low thermal conductivity, for example, a general-purpose printed wiring board. The printed wiring board 2 may also be formed of, for example, ceramics such as aluminum oxide, aluminum nitride, or silicon carbide. The printed wiring board 2 may also be provided with through holes (not shown) for mounting electronic components, etc. The through holes are holes formed in the printed wiring board 2, the inner surfaces of which are copper-plated.

[0018] A circuit that determines the function of electronic device 110 is formed on printed wiring board 2. The circuit that determines the function of electronic device 110 is composed of wiring (not shown) and electronic components such as electronic element 4 and connector 3.

[0019] The wiring (not shown) is formed on the surface or inside of the printed wiring board 2. The wiring has a thickness of 1 μm or more and 2000 μm or less. The wiring is made of a conductive material, such as copper, nickel, gold, aluminum, silver, tin, or an alloy thereof.

[0020] Electronic components such as electronic element 4 and connector 3 are mounted on printed wiring board 2 and are electrically connected by wiring formed on the surface of or inside printed wiring board 2.

[0021] Here, the circuit configuration of electronic device 110 will be described with reference to Fig. 3. Fig. 3 is a block diagram showing an example of the circuit configuration of electronic device 110. Note that in Fig. 3, the interface is indicated by the symbol "I / F" for simplification.

[0022] As shown in FIG. 3, the circuitry of electronic device 110 includes a control integrated circuit 51, electronic elements 41, a memory integrated circuit 52, an input / output integrated circuit 53, an external interface 30, a power supply integrated circuit 54, an oscillator 42, and a clock driver integrated circuit 55.

[0023] The control integrated circuit 51 is responsible for control and processing of the electronic device 110. The control integrated circuit 51 is, for example, a central processing unit (CPU), a field programmable gate array (FPGA), or an application specific integrated circuit (ASIC).

[0024] The electronic element group 41 is provided to assist the functions of the control integrated circuit 51, such as improving the stability of the power supply or controlling signals. The electronic element group 41 is a plurality of electronic elements 4, and includes, for example, resistors, capacitors, or inductors.

[0025] The memory integrated circuit 52 serves as a working area for the control integrated circuit 51 and stores data and reads and writes data. The memory integrated circuit 52 is, for example, a dynamic random access memory (DRAM) or a static random access memory (SRAM). The memory integrated circuit 52 is composed of a capacitor, a field effect transistor, and peripheral circuits. That is, a general-purpose semiconductor memory can be applied as the memory integrated circuit 52.

[0026] The input / output integrated circuit 53 and the external interface 30 input or output signals between the control integrated circuit 51 and an input device (not shown) and an output device (not shown). The input device transmits an input signal to the input / output integrated circuit 53 via the external interface 30. The input / output integrated circuit 53 converts the input signal from the input device into a digital signal, filters the signal, and transmits the signal to the control integrated circuit 51. The control integrated circuit 51 processes the input signal received from the input / output integrated circuit 53 and generates a control signal for the output device. The control signal generated by the control integrated circuit 51 is converted by the input / output integrated circuit 53 into power or a signal for controlling the output device, and transmitted to the external device via the external interface 30.

[0027] The input / output integrated circuit 53 transmits and receives signals between the control integrated circuit 51 and external devices (not shown) such as input devices and output devices, and shapes or converts the signals into an appropriate format. The input / output integrated circuit 53 is composed of, for example, a CMOS (Complementary Metal Oxide Semiconductor) circuit, a diode, and a resistor. The CMOS element, which is a switching element applied to the CMOS circuit, is formed of, for example, silicon (Si), silicon carbide (SiC), gallium nitride (GaN), or the like. The diode is also formed of, for example, silicon (Si), silicon carbide (SiC), gallium nitride (GaN), or the like.

[0028] The external interface 30 connects the electronic device 110 to an external device (not shown) such as an input device and an output device in order to transmit and receive signals and communicate between the control integrated circuit 51 and the external device. The external interface 30 is, for example, a Small Form Factor Pluggable (SFP) module, Recommended Standard 232 (RS-232), or Ethernet (registered trademark). The SFP module is an expansion module for converting electronic signals into optical signals. RS-232 is one of the connection standards for serial communication between electronic devices. Ethernet is one of the computer networks and is a communication standard for wired local area networks. The components of the external interface 30 include a connector 3 (see FIG. 4) conforming to each standard.

[0029] The power supply integrated circuit 54 generates a power supply voltage to be supplied to the control integrated circuit 51. The power supply integrated circuit 54 is configured by, for example, a linear regulator or a switching regulator. When the power supply integrated circuit 54 is configured by a switching regulator, the power supply integrated circuit 54 includes an inverter circuit, a transformer circuit, a rectifier circuit, and the like.

[0030] The inverter circuit includes switching elements such as MOS type field effect transistors (MOSFETs: Metal Oxide Semiconductor Field Effect Transistors) or insulated gate bipolar transistors (IBGTs: Insulated Gate Bipolar Transistors). Such switching elements are made of materials such as silicon (Si), silicon carbide (SiC), or gallium nitride (GaN).

[0031] The transformer circuit includes a primary high-voltage winding connected to the inverter circuit, a core material such as ferrite, and a secondary low-voltage winding.

[0032] The rectifier circuit includes a diode, which is made of, for example, silicon (Si), silicon carbide (SiC), gallium nitride (GaN), or the like.

[0033] The oscillator 42 and the clock driver integrated circuit 55 control the timing and synchronization of the entire circuitry of the electronic device 110. The oscillator 42 generates a periodic clock signal, and the clock driver integrated circuit 55 supplies the generated clock signal to the control integrated circuit 51. The control integrated circuit 51 operates in synchronization with the clock signal, and executes instructions and processes data with precise timing.

[0034] The oscillator 42 is, for example, a crystal oscillator, a ceramic oscillator, an LC oscillator, etc. The oscillator 42 is formed from, for example, crystal, silicon, ceramic, or other material.

[0035] The clock driver integrated circuit 55 is composed of a CMOS circuit, an LVDS (Low Voltage Differential Signaling) circuit, or the like. The CMOS circuit and the LVDS circuit transmit the clock signal to the control integrated circuit 51. The CMOS circuit transmits the clock signal using a single-ended signal. The LVDS circuit transmits the clock signal using a differential signal.

[0036] Although the circuit configuration of the electronic device 110 has been described as including the control integrated circuit 51, the electronic element group 41, the memory integrated circuit 52, the input / output integrated circuit 53, the external interface 30, the power supply integrated circuit 54, the oscillator 42, and the clock driver integrated circuit 55, the circuit configuration may include a second control integrated circuit. When the circuit configuration of the electronic device 110 includes the second control integrated circuit, bidirectional communication is performed between the control integrated circuit 51 and the second control integrated circuit via wiring. For example, a high-speed serial interface signal, a clock signal, and a reset signal are transmitted. Here, the high-speed serial interface is PCI Express, SATA (Serial ATA), or the like. In addition, wiring for other communication may be formed between the control integrated circuit 51 and the second main control circuit.

[0037] Not limited to the second control integrated circuit, the circuit configuration of the electronic device 110 may include three or more control integrated circuits. Also, not limited to the control integrated circuit, the electronic element group 41, the memory integrated circuit 52, the input / output integrated circuit 53, the external interface 30, the power supply integrated circuit 54, the oscillator 42, and the clock driver integrated circuit 55 may also have a circuit configuration including two or more of them.

[0038] As described above, the circuit of electronic device 110 is formed by electrically connecting electronic components such as electronic element 4 and connector 3 mounted on printed wiring board 2 by wiring (not shown) formed on the surface or inside of printed wiring board 2. The electronic components mounted on printed wiring board 2 will be described with reference to Figs. 4, 5 and 6. Fig. 4 is a top view showing components of electronic device 110 excluding housing 1. Fig. 5 is a perspective view showing components of electronic device 110 excluding housing 1. Fig. 6 is a side view seen from the direction indicated by arrow II in Fig. 5.

[0039] As shown in Figures 4 and 5, a group of electronic elements 41, a memory integrated circuit 52, an input / output integrated circuit 53, a connector 3 functioning as an external interface 30, a power supply integrated circuit 54, an oscillator 42, and a clock driver integrated circuit 55 are mounted on the printed wiring board 2, surrounding the control integrated circuit 51.

[0040] These electronic components that configure the circuit of the electronic device 110 are densely mounted on the printed wiring board 2. In particular, electronic element group 41, that is, electronic element group 41a, electronic element group 41b, and electronic element group 41c, are densely mounted around the control integrated circuit 51. The electronic element group 41a, electronic element group 41b, and electronic element group 41c are a plurality of electronic elements 4, and the combinations of electronic elements 4 may be the same or different.

[0041] Of the electronic components mounted on the printed wiring board 2, excluding the connector 3, the electronic element group 41, the oscillator 42, the control integrated circuit 51, the memory integrated circuit 52, the input / output integrated circuit 53, the power supply integrated circuit 54, and the clock driver integrated circuit 55 are classified as electronic elements 4.

[0042] The electronic elements 4 are electronic components that make up a circuit and have a specific function such as controlling and processing an electric signal. The electronic elements 4 include, for example, resistors, coils, capacitors, transistors, vacuum tubes, diodes, sensors, and integrated circuits 5.

[0043] An integrated circuit 5 is a type of electronic element 4, and among the electronic components mounted on the printed wiring board 2, a control integrated circuit 51, a memory integrated circuit 52, an input / output integrated circuit 53, a power supply integrated circuit 54, and a clock driver integrated circuit 55 are classified as integrated circuits 5.

[0044] The connector 3 is an electronic component that connects the electronic device 110 to an external device, and has a function of transmitting signals but does not have a function of controlling and processing electrical signals. Therefore, the connector 3 is not included in the electronic element 4.

[0045] As shown in Figures 1 and 2, the connector 3 is provided in the housing 1 so as to cover the opening 11 of the housing 1. The connector 3 includes a metal terminal for forming a conductive path, and a resin outer shell for holding and protecting the terminal and electrically isolating the terminal from other conductors. The terminal of the connector 3 is electrically connected to wiring (not shown) formed on the surface or inside of the printed wiring board 2. The connector 3 is electrically connected to an external device (not shown) via a cable (not shown).

[0046] The connector 3 is a portion that receives an electrical signal from an external device via a cable. Therefore, when electromagnetic noise generated in an external device propagates through the cable, the connector 3 becomes a noise intrusion point. A portion of the external electromagnetic noise that intrudes from the connector 3 is conducted through space inside the housing 1 as unwanted electromagnetic waves. In addition, a portion of the external electromagnetic noise is conducted as conducted noise through power lines, signal lines, circuit patterns on printed circuit boards, etc.

[0047] Connector 3 is a connection part with an external device, and is a part that may come into contact with a statically charged object or human body and cause electrostatic discharge. Part of the electrostatic discharge becomes electromagnetic noise, some of which is conducted through space as unwanted electromagnetic waves. When electrostatic discharge occurs in connector 3, connector 3 becomes a noise intrusion point. Part of the external electromagnetic noise that enters through connector 3 is conducted through space inside housing 1 as unwanted electromagnetic waves.

[0048] An electronic element 4 and an integrated circuit 5, which is a type of electronic element 4, are mounted on a printed wiring board 2. When external electromagnetic noise enters from the connector 3, the electronic element 4 and the integrated circuit 5, which is a type of electronic element 4, can become noise-affected parts, in which the voltage fluctuates due to unwanted electromagnetic waves, which are a part of the external electromagnetic noise.

[0049] When the electronic element 4 becomes a noise-affected part, that is, when unwanted electromagnetic waves are coupled to the electronic element 4 and the voltage applied to the electronic element 4 fluctuates, the functions of the electronic element 4, such as signal control, processing, and conversion, may be impaired. For example, when the signal of the electronic element 4 is distorted by the noise voltage, the electronic element 4 causes malfunctions, such as output of an erroneous control signal and operation at an incorrect timing. In this way, the electronic element 4, which is a noise-affected part, is a direct cause of malfunction of the electronic device 110.

[0050] An integrated circuit 5, which is a type of electronic element 4, will malfunction if a voltage exceeding the allowable fluctuation value of the power supply voltage is applied. Due to the recent trend toward lower drive voltages, the allowable fluctuation value of the power supply voltage of the integrated circuit 5 has decreased. As a result, even a slight voltage fluctuation caused by unnecessary electromagnetic waves with small energy is highly likely to cause the integrated circuit 5 to malfunction. Therefore, among the electronic elements 4, the integrated circuit 5 particularly requires measures against noise.

[0051] 4 and 5, electronic element group 41, that is, electronic element group 41a, electronic element group 41b, and electronic element group 41c, are densely mounted in the vicinity of electronic element 4, which is the noise-affected portion, particularly around control integrated circuit 51. For this reason, the mounting area for electromagnetic noise countermeasure components such as an electromagnetic shield is limited.

[0052] 4 and 5, a ground wiring 61 serving as a ground is provided on the surface or inside of the printed wiring board 2. In FIG. 4 and FIG. 5, an example in which the ground wiring 61 is formed on the surface of the printed wiring board 2 is shown.

[0053] The ground wiring 61 is a conductive flat surface, and serves as an electrical reference for the circuit of the electronic device 110. The potential of the ground wiring 61 is FG (Frame Ground), which is a potential different from SG (Signal Ground), which serves as a reference potential for control signals. The ground wiring 61 is made of a conductive material, such as copper, nickel, gold, aluminum, silver, tin, or an alloy thereof. It is desirable for the ground wiring 61 to be flat and have a constant size.

[0054] The conductor 7 is provided on the ground wiring 61, and the ground wiring 61 and the conductor 7 are electrically connected to each other. It is desirable that the length of the ground wiring 61 from the connection between the ground wiring 61 and the conductor 7 to the outer periphery of the ground wiring 61 be equal to or greater than ¼ of the wavelength of the unwanted electromagnetic waves.

[0055] A first metal plate (not shown) may be provided at the bottom of the printed wiring board 2 as a ground having the same function as the ground wiring 61. The first metal plate is made of a conductive material with high conductivity. For example, it is made of copper, nickel, gold, aluminum, silver, tin, or an alloy thereof. For the purpose of reducing manufacturing costs, it is preferable to form it from an inexpensive conductive material. The potential of the first metal plate is the FG potential, similar to that of the ground wiring 61. The first metal plate formed at the bottom of the printed wiring board 2 and the conductor 7 are electrically connected via a through hole (not shown) provided in the printed wiring board 2. It is preferable that the length of the first metal plate from the connection part between the first metal plate and the conductor 7 to the outer periphery of the first metal plate is ¼ or more of the wavelength of the unnecessary electromagnetic waves. The first metal plate may also be provided with a through hole (not shown) for mounting electronic components, etc.

[0056] The conductor 7 is provided between the connector 3, which is a noise intrusion part, and the electronic element 4, which is a noise-affected part. The conductor 7 connected to the ground wiring 61 or the first metal plate is a countermeasure component for unwanted electromagnetic waves, which are part of the external electromagnetic noise that intrudes into the inside of the housing 1 from a specific direction, and is desirably installed as close as possible to the connector 3, which is a noise intrusion part. Specifically, it is desirably that the distance from the noise intrusion part to the conductor 7 is within 1 / 2 of the distance between the noise intrusion part and the electronic element 4. To obtain a greater effect as an electromagnetic noise countermeasure component, it is desirably within 1 / 4 of the distance between the noise intrusion part and the electronic element 4.

[0057] Moreover, it is desirable that the conductor 7 is provided on a straight line connecting the noise intrusion part and the electronic element 4. Specifically, as shown in Fig. 6, it is desirable to install the conductor 7 so that its center position is the same as the center position of the connector 3, which is the noise intrusion part. This is because the magnetic flux density of the unwanted electromagnetic waves entering from the noise intrusion part becomes high on the straight line connecting the noise intrusion part and the electronic element 4.

[0058] The conductor 7 is made of a conductive material with high conductivity. For example, it is made of copper, nickel, gold, aluminum, silver, tin, or an alloy thereof. For the purpose of reducing manufacturing costs, it is preferable to make it of an inexpensive conductive material.

[0059] The length L of the conductor 7 is ¼ of the wavelength of the unwanted electromagnetic waves entering from the noise intrusion part. Here, the length L of the conductor 7 is the length in the longitudinal direction of the conductor 7, as shown in Fig. 5, and indicates the length from the connection part between the conductor 7 and the ground wiring 61 to the upper end part of the conductor 7.

[0060] The conductor 7 is linear and not bent or folded. The conductor 7 may be rod-shaped or flat as long as it is linear. The conductor 7 may have a lead portion for fixing to the printed wiring board 2. The lead portion of the conductor 7 is, for example, a bendable metal lead wire, and serves to insert into a through hole provided in the printed wiring board 2 and fix to the printed wiring board 2. The conductor 7 may also be a metal support such as a spacer or supporter used for fixing between the housing 1 and the printed wiring board 2, or between the printed wiring boards 2 and each other. A typical spacer or supporter has a screw structure at the end.

[0061] 5, it is preferable that the width D of the conductor 7 is as large as possible. Here, the width D of the conductor 7 is the length in the direction perpendicular to the length L of the conductor 7 in the longitudinal direction.

[0062] Although an example of a configuration of electronic device 110 in which connector 3 is provided in opening 11 of metal or resin housing 1 has been described, a configuration in which opening 11a is provided in metal housing 1a without providing connector 3 may also be used. This configuration will be described with reference to FIG. 7. FIG. 7 is a cross-sectional view showing another example of electronic device 110 according to embodiment 1. FIG. 7 shows a cross-section corresponding to line II of electronic device 110 shown in FIG. 1.

[0063] As shown in FIG. 7, the metal housing 1a having the opening 11a may be provided so as to cover the printed wiring board 2, a part of the connector 3, the electronic element 4, the ground wiring 61, and the conductor 7. The opening 11a provided in the metal housing 1a also serves as an opening of the metal housing 1a electrically. Therefore, the opening 11a provided in the metal housing 1a serves as a noise intrusion part of the metal housing 1a. The conductor 7 may be provided between the opening 11a of the metal housing 1a, which is the noise intrusion part, and the electronic element 4, which is the noise-receiving part, to serve as a countermeasure part for the external electromagnetic noise that intrudes into the housing from the opening 11a provided in the metal housing 1a. In this case, it is preferable that the conductor 7 is provided on a straight line connecting the opening 11a of the metal housing 1a and the electronic element 4.

[0064] <Manufacturing method of electronic device according to the first embodiment> Next, a method for manufacturing the electronic device 110 according to the first embodiment of the present disclosure will be described. Note that in this embodiment, only a method for connecting the ground wiring 61 or the first metal plate to the conductor 7 among the manufacturing steps of the electronic device 110 will be described.

[0065] First, a description will be given of an example in which ground wiring 61 is provided on the surface of printed wiring board 2. When ground wiring 61 is formed on the surface of printed wiring board 2, conductor 7 is surface-mounted on printed wiring board 2. Conductor 7 is fixed onto ground wiring 61 formed on the surface of printed wiring board 2 via solder or conductive adhesive.

[0066] The conductor 7 may be connected to the ground wiring 61 formed on the surface of the printed wiring board 2 through a through hole (not shown) provided in the printed wiring board 2. The through hole is a hole formed in the printed wiring board 2 with an inner surface plated with copper, and is electrically connected to the ground wiring 61. The ground wiring 61 and the conductor 7 can be connected by fixing the conductor 7 to the through hole. The fixing between the through hole and the conductor 7 may be realized by using the conductor 7 having a lead portion (not shown) and inserting the lead portion of the conductor 7 into the through hole and using solder or a conductive adhesive. Alternatively, a spacer or supporter having a screw structure at the end (not shown) may be used as the conductor 7, and a screw at the end of the conductor 7 may be inserted into the through hole formed in the printed wiring board 2 to be fixed with the screw.

[0067] In addition, an example in which a ground wiring 61 is provided inside the printed wiring board 2 will be described. When the ground wiring 61 is formed inside the printed wiring board 2, the conductor 7 is connected to the ground wiring 61 formed inside the printed wiring board 2 via the above-mentioned through-hole provided in the printed wiring board 2. The through-hole is electrically connected to the ground wiring 61. The through-hole and the conductor 7 may be fixed by inserting the lead portion of the conductor 7 into the through-hole using solder or a conductive adhesive by using a conductor 7 having a lead portion. Also, by using a spacer or supporter having a screw structure at the end as the conductor 7, a screw at the end of the conductor 7 may be inserted into the through-hole formed in the printed wiring board 2 and fixed with the screw.

[0068] An example in which a first metal plate is provided at the bottom of the printed wiring board 2 will be described. When the first metal plate is formed at the bottom of the printed wiring board 2, the conductor 7 is electrically connected to the first metal plate formed at the bottom of the printed wiring board 2 through the aforementioned through-hole provided in the printed wiring board 2. For example, the first metal plate, which is the ground, and the ground wiring formed on the surface of the printed wiring board 2 are electrically connected through the through-hole. The conductor 7 is fixed on the ground wiring formed on the surface of the printed wiring board 2 through solder or a conductive adhesive, so that the conductor 7 and the first metal plate are electrically connected. In addition, by using the conductor 7 having a lead portion, the lead portion of the conductor 7 may be inserted into the through-holes of the printed wiring board 2 and the first metal plate, and the lead portion of the conductor 7 and the first metal plate may be connected using solder or a conductive adhesive.

[0069] <Function of the Electronic Device of the First Embodiment> Next, the operation of electronic device 110 according to embodiment 1 of the present disclosure will be described.

[0070] The conductor 7 connected to the ground wiring 61 serves to reduce external electromagnetic noise entering through the noise intrusion portion.

[0071] The conductor 7 connected to the ground wiring 61 serves as a monopole antenna and efficiently absorbs unwanted electromagnetic waves in a specific wavelength range by utilizing resonance. When unwanted electromagnetic waves are incident on the conductor 7 connected to the ground wiring 61, the unwanted electromagnetic waves are absorbed as an induced current in the conductor 7. When unwanted electromagnetic waves having a wavelength four times the length L of the conductor 7 are incident on the conductor 7 connected to the ground wiring 61, in other words, when the wavelength of the unwanted electromagnetic waves incident on the conductor 7 is ¼ the length L of the conductor 7, the unwanted electromagnetic waves are in a resonant state with the conductor 7 connected to the ground wiring 61. When the unwanted electromagnetic waves are in a resonant state with the conductor 7 connected to the ground wiring 61, a current easily flows, and the unwanted electromagnetic waves are efficiently absorbed.

[0072] As described above, the conductor 7 is straight without any bends or folds. This is because the conductor 7 connected to the ground wiring 61 functions as a monopole antenna and efficiently absorbs unwanted electromagnetic waves of a specific wavelength. If the conductor 7 is bent or folded, the effective length L of the conductor 7 may change, which may change the wavelength of the electromagnetic waves that resonate with the conductor 7. If the wavelength of the electromagnetic waves that resonate with the conductor 7 changes and the resonant wavelength range of the conductor 7 deviates from the wavelength of the unwanted electromagnetic waves, the unwanted electromagnetic waves cannot be efficiently absorbed. Furthermore, if the conductor 7 is bent or folded, a portion where the electric field is concentrated may be created, which may make it difficult to receive the electromagnetic waves in the portion where the electric field is concentrated.

[0073] The contact point between the ground wiring 61 and the first metal plate, i.e., the ground, and the conductor 7 functions as the power feed point of the monopole antenna. When unwanted electromagnetic waves reach the conductor 7, a current is induced in the conductor 7, and the induced current flows to the ground. In other words, by connecting the conductor 7 to the ground, the unwanted electromagnetic waves can be converted into a current and absorbed.

[0074] The ground wiring 61 and the first metal plate, i.e., the ground, function as a reflecting surface for the conductor 7. The ground reflects electromagnetic waves, and the waves reflected by the ground interfere with the original waves, increasing the electromagnetic waves incident on the conductor 7. When unwanted electromagnetic waves reach the vicinity of the conductor 7 connected to the ground, the unwanted electromagnetic waves incident on the conductor 7 are increased by the ground, and the unwanted electromagnetic waves can be efficiently absorbed.

[0075] As described above, it is desirable for the ground to be flat and have a certain size, for example, such that the length from the connection between the ground wiring 61 and the conductor 7 to the outer periphery of the ground wiring 61 is equal to or greater than ¼ of the wavelength of the unwanted electromagnetic waves. A flat ground can accurately reflect electromagnetic waves and improve the absorption performance of a monopole antenna. A ground with a certain size has a sufficient size to reflect electromagnetic waves, so it can improve the absorption performance of a monopole antenna.

[0076] The conductor 7 also has the effect of absorbing and reflecting unwanted electromagnetic waves as a shield. The reason that the conductor 7 acts as a shield and absorbs unwanted electromagnetic waves is that when unwanted electromagnetic waves are incident on the conductor 7, the energy of the unwanted electromagnetic waves is lost as an induced current. This loss increases as the thickness of the material increases. Therefore, as described above, it is desirable that the width D of the conductor 7 is as large as possible.

[0077] The reason why the conductor 7 has the effect of reflecting unwanted electromagnetic waves as a shield is that the conductor 7 is made of a conductive material with high conductivity. When the specific impedance of the conductor 7 is low compared to the specific impedance of the space, the shielding effect due to reflection is increased. Here, the specific impedance represents the properties of radio waves when they are transmitted as plane waves through the target material, and the higher the conductivity, the lower the specific impedance. As described above, the conductor 7 is made of a conductive material with high conductivity, and therefore has the effect of reflecting unwanted electromagnetic waves.

[0078] The conductor 7 has an improved effect as a shield when the width D is large and the conductor 7 is provided on a straight line connecting the noise intrusion part and the electronic element 4. This is because by providing the conductor 7 with a large width D in the middle of the intrusion path of the unwanted electromagnetic waves, the distance that the unwanted electromagnetic waves travel to reach the electronic element 4 is extended. Since radio waves attenuate in proportion to the square of the distance, the energy of the radio waves that reach the electronic element 4 is reduced.

[0079] In this way, the conductor 7 can absorb and reflect unwanted electromagnetic waves and reduce external electromagnetic noise as a monopole antenna and shield in the electronic device 110. Since the conductor 7 absorbs and reflects unwanted electromagnetic waves, it is desirable to install it in the vicinity of the noise intrusion part.

[0080] 5, the conductor 7 is provided between the connector 3, which is a noise intrusion part, and the electronic element 4, which is a noise-receiving part. Unwanted electromagnetic waves that intrude from the connector 3 are absorbed and reflected by the conductor 7 provided between the connector 3 and the electronic element 4. In other words, the unwanted electromagnetic waves reach the conductor 7 before reaching the electronic element 4, and are absorbed by the conductor 7.

[0081] Since unwanted electromagnetic waves are emitted from the noise entry point, the closer the conductor 7 is placed to the noise entry point, the more it can absorb the unwanted electromagnetic waves entering from the connector 3 before they are diffused.

[0082] By reducing the unwanted electromagnetic waves reaching the electronic element 4, which is the noise-affected part, it is possible to suppress the unwanted electromagnetic waves from being coupled to the electronic element 4. In other words, the conductor 7 can prevent the electronic element 4 from malfunctioning due to the unwanted electromagnetic waves.

[0083] Furthermore, among the components of the electronic device 110, the wiring (not shown) may also be a noise-affected part. The wiring transmits information by changes in current or voltage. For this reason, when the wiring becomes a noise-affected part, that is, when external electromagnetic noise is coupled to the wiring and the current or voltage applied to the wiring fluctuates, the wiring that has become a noise-affected part transmits a signal different from the original one. When this signal different from the original one is transmitted to the electronic element 4, the functions of the electronic element 4, such as control, processing, and conversion of signals, are impaired, which may cause the electronic device 110 to malfunction. In this way, the wiring that is a noise-affected part is an indirect cause of the malfunction of the electronic device 110.

[0084] The conductor 7 absorbs noise, thereby reducing the amount of unwanted electromagnetic waves that reach the wiring, which is the noise-affected portion, and thus making it possible to suppress coupling of noise to the wiring. In particular, noise is reduced in the region closer to the electronic element 4 than the conductor 7. By suppressing coupling of noise to the wiring, the wiring will no longer transmit a signal different from the intended signal to the electronic element 4. In other words, by suppressing coupling of noise to the wiring, which is the noise-affected portion, the conductor 7 indirectly prevents malfunction of the electronic element 4 due to unwanted electromagnetic waves.

[0085] In order for the conductor 7 to efficiently absorb unwanted electromagnetic waves, it is desirable to design the length L of the conductor 7 with the aim of absorbing a specific unwanted electromagnetic wave. Since the propagation speed in a conductor is slower than the propagation speed in a vacuum depending on the dielectric constant of the conductor, the length of the conductor 7 is designed taking into consideration the absorption of radio waves in a frequency band corresponding to a wavelength slightly shorter than the wavelength calculated from the length of the conductor 7.

[0086] In order to prevent the conductor 7 from re-emitting the unwanted electromagnetic waves absorbed by it, it is desirable not to install a noise source inside the electronic device 110 near the conductor 7. An example of the noise source inside the electronic device 110 is an electronic element 4 having a switching function. The conductor 7 may be designed so that the length L of the conductor 7 is not a resonance length for the wavelength of the unwanted electromagnetic waves emitted by the noise source inside the electronic device 110. Furthermore, a conductor shield that is not connected to ground may be provided between the conductor 7 and the noise source inside the electronic device 110.

[0087] Here, we compare this with electromagnetic shielding, a conventional method for improving the electromagnetic noise resistance of electronic devices. Electromagnetic shielding is a method for blocking the spatial conduction of electromagnetic noise in the air by surrounding an object with an electromagnetic shielding case made of conductive material. In general, electromagnetic noise resistance can be improved by surrounding the electronic elements, which are the parts affected by the noise. However, since electronic elements are mounted at high density on a printed wiring board, there are cases where it is not possible to secure an area for mounting an electromagnetic shield near the electronic elements.

[0088] In contrast, in the first embodiment of the present disclosure, the conductor 7 is placed near the noise intrusion portion in order to improve the electromagnetic noise resistance. The conductor 7 does not need to surround the noise-affected portion surrounded by electronic components densely packed. Therefore, according to the first embodiment of the present disclosure, even if the electronic element 4 is present in an area where electronic components are densely packed, the electromagnetic noise resistance of the electronic device 110 can be improved.

[0089] Furthermore, in Patent Document 1, in order to install the electromagnetic shield case so as to surround the electronic element, the electromagnetic shield case is provided with a pressure spring, a recess for pressing the electronic element, a stopper spring, etc. In this way, since the electromagnetic shield case needs to be processed into a predetermined shape, the number of parts and processing steps increase, leading to an increase in the manufacturing cost of the product.

[0090] In contrast, in the first embodiment of the present disclosure, the conductor 7 installed to enhance the electromagnetic noise resistance is formed of an inexpensive conductive material and processed into a rod-like or planar shape. No complicated process is required for installing the conductor 7. Therefore, according to the first embodiment of the present disclosure, the electromagnetic noise resistance of the electronic device 110 can be improved at low cost.

[0091] <Effects of the Electronic Device of the First Embodiment> As described above, according to the electronic device 110 according to the first embodiment of the present disclosure, the conductor 7, which is provided between the noise intrusion section and the electronic element 4 and connected to the ground, suppresses coupling of external electromagnetic noise with the noise-receiving section provided on the electronic element 4 side relative to the conductor 7. Therefore, even when the electronic element 4 is present in an area where electronic components are densely mounted, the electromagnetic noise resistance of the electronic device 110 can be improved.

[0092] Moreover, according to electronic device 110 according to embodiment 1 of the present disclosure, the electromagnetic noise resistance of electronic device 110 can be improved at low cost.

[0093] Variation 1. Next, a first modification of the first embodiment will be described. In the first embodiment, a configuration in which one conductor 7 connected to the ground wiring 61 is provided will be described. In the first modification, a configuration in which a plurality of conductors 7 connected to the ground wiring 61 are provided will be described. Note that the same components as those in the first embodiment will be given the same reference numerals, and descriptions of the same or corresponding parts will be omitted. Hereinafter, an electronic device 111 according to the first modification of the first embodiment will be described with reference to the drawings.

[0094] <Configuration of Electronic Device According to Variation 1 of First Embodiment> 8 is a perspective view showing components, excluding the housing, of electronic device 111 according to Variation 1 of Embodiment 1. In FIG. 8, an example in which ground wiring 61 is formed on the surface of printed wiring board 2 is shown.

[0095] As shown in Fig. 8, a plurality of conductors 7 are provided between the connector 3, which is the noise intrusion portion, and the electronic element 4, which is the noise-receiving portion. The plurality of conductors 7 each have a different length L. Fig. 8 shows an example in which five conductors 7 are provided, namely, conductor 7a, conductor 7b, conductor 7c, conductor 7d, and conductor 7e, and the lengths thereof are La, Lb, Lc, Ld, and Le, respectively.

[0096] The multiple conductors 7 are electrically connected to a ground wiring 61 formed on the surface or inside of the printed wiring board 2. It is desirable that the length of the ground wiring 61 from the connection between the ground wiring 61 and the conductors 7 to the outer periphery of the ground wiring 61 be equal to or greater than ¼ of the wavelength of the electromagnetic noise.

[0097] The number of conductors 7 provided in electronic device 111 is not limited to five, and may be less than five or more than five.

[0098] <Function of Electronic Device According to Modification 1 of First Embodiment> The multiple conductors 7 connected to the ground wiring 61 function as a monopole antenna to efficiently absorb unwanted electromagnetic waves having a wavelength four times the length L of each of the multiple conductors 7. For example, when five conductors 7 each having a different length L are provided as shown in FIG. 8, unwanted electromagnetic waves corresponding to the five lengths L of the five conductors 7 are efficiently absorbed. In other words, by providing multiple conductors 7 with different lengths L, the wavelength range of unwanted electromagnetic waves that can be reduced by the conductors 7 can be expanded. The more conductors 7 that are installed, the wider the wavelength range of unwanted electromagnetic waves that can be reduced.

[0099] By widening the wavelength range of the unwanted electromagnetic waves that can be reduced by the conductors 7, the unwanted electromagnetic waves that reach the electronic element 4, which is the noise-affected part, can be further reduced, and the coupling of the unwanted electromagnetic waves to the electronic element 4 can be further suppressed. In other words, the multiple conductors 7 can prevent the electronic element 4 from malfunctioning due to the unwanted electromagnetic waves.

[0100] <Effects of the Electronic Device According to Modification 1 of the First Embodiment> As described above, according to the electronic device 111 relating to the first variant of the first embodiment of the present disclosure, by providing a plurality of conductors 7 having different lengths L, it is possible to further improve the electromagnetic noise resistance of the electronic device 111 even when the electronic element 4 is present in an area where electronic components are densely packed.

[0101] Variation 2. Next, a second modification of the first embodiment will be described. In the first embodiment, a linear conductor 7 has been described. In the second modification, a linear conductor 71 with a hollow interior will be described. Note that the same components as in the first embodiment will be given the same reference numerals, and descriptions of the same or corresponding parts will be omitted. Hereinafter, an electronic device 112 according to the second modification of the first embodiment will be described with reference to the drawings.

[0102] <Configuration of Electronic Device According to Modification 2 of First Embodiment> Fig. 9 is a cross-sectional view showing components excluding the housing of electronic device 112 according to Variation 2 of Embodiment 1. Fig. 9 shows a cross-section of electronic device 112 corresponding to line segment II of electronic device 110 shown in Fig. 1. Fig. 9 shows an example in which ground wiring 61 is formed on the surface of printed wiring board 2.

[0103] 9, a conductor 71 corresponding to the conductor 7 in the first embodiment is provided between the connector 3, which is a noise intrusion part, and the electronic element 4, which is a noise-receiving part. The conductor 71 is linear and hollow inside.

[0104] The conductor 71 may have a lead portion (not shown) for fixing to the printed wiring board 2. The lead portion of the conductor 7 is, for example, a bendable metal lead wire, and serves to insert into a through hole (not shown) provided in the printed wiring board 2 and fix to the printed wiring board 2. The conductor 71 may also be a hollow metal support having a screw structure at the end, such as a spacer or a supporter. Here, the hollow metal support is different from the metal support such as the spacer or supporter described in the first embodiment. The metal support, which is a type of the conductor 7 described in the first embodiment, is not hollow inside, while the metal support, which is a type of the conductor 71, is hollow inside.

[0105] The conductor 71 is electrically connected to the ground wiring 61 formed on the surface or inside of the printed wiring board 2. It is desirable that the length of the ground wiring 61 from the connection between the ground wiring 61 and the conductor 71 to the outer periphery of the ground wiring 61 is equal to or greater than ¼ of the wavelength of the unwanted electromagnetic waves.

[0106] <Method of Manufacturing Electronic Device According to Modification 2 of First Embodiment> When the ground wiring 61 is formed on the surface of the printed wiring board 2, the hollow conductor 71 is surface-mounted on the printed wiring board 2. The hollow conductor 71 is fixed onto the ground wiring 61 formed on the surface of the printed wiring board 2 by solder or a conductive adhesive.

[0107] The conductor 7 may be connected to the ground wiring 61 formed on the surface of the printed wiring board 2 via a through hole (not shown) provided in the printed wiring board 2. The through hole and the conductor 7 may be fixed by using a conductor 71 having a lead portion (not shown) and inserting the lead portion of the conductor 71 into the through hole and using solder or a conductive adhesive. Alternatively, the conductor 71 may be used with a screw structure at its end (not shown) and the screw at the end of the conductor 71 may be inserted into the through hole and fixed with the screw.

[0108] When the ground wiring 61 is formed inside the printed wiring board 2, the conductor 71 having a hollow interior is connected to the ground wiring 61 formed inside the printed wiring board 2 via the aforementioned through-hole provided in the printed wiring board 2. The through-hole and the conductor 7 may be fixed by using a conductor 71 having a lead portion (not shown) and inserting the lead portion of the conductor 71 into the through-hole and using solder or a conductive adhesive. Alternatively, by using a conductor 71 having a screw structure at its end (not shown), the screw at the end of the conductor 71 may be inserted into the through-hole and fixed with the screw.

[0109] When a first metal plate (not shown) is formed under the printed wiring board 2, the conductor 71 having a hollow interior is connected to the first metal plate formed under the printed wiring board 2 through the aforementioned through-hole provided in the printed wiring board 2. The conductor 71 is inserted into the through-hole, and fixed on the first metal plate provided under the printed wiring board 2 via solder or conductive adhesive. Alternatively, by using the conductor 71 having a lead portion, the lead portion of the conductor 71 may be inserted into the through-hole, and the lead portion of the conductor 71 may be connected to the first metal plate using solder or conductive adhesive. By using the conductor 71 having a screw structure at the end, the conductor 7 may be inserted into the through-hole, and then the screw at the end of the conductor 71 may be inserted into the screw hole formed in the first metal plate to be screwed and fixed.

[0110] Conductor 71 may be fixed by fitting hollow conductor 71 into a spacer or supporter having a screw structure at an end (not shown), which is a type of non-hollow conductor 7 in embodiment 1. At this time, hollow conductor 71 is electrically connected to the non-hollow spacer or supporter. Furthermore, the non-hollow spacer or supporter is connected to ground wiring 61 formed on the surface or inside of printed wiring board 2 via a through hole. The conductor 71, which is hollow inside, may be fitted into a spacer or supporter, which is hollow inside.

[0111] <Function of Electronic Device According to Modification 2 of First Embodiment> Conductor 71, which is hollow inside, is light in weight by the weight of the hollow portion. Therefore, electronic device 112 provided with conductor 71, which is hollow inside, is light in weight. In addition, conductor 71 being lightweight reduces the load on the bonding point between conductor 71 and printed wiring board 2, improving the long-term reliability of bonding of conductor 71 to printed wiring board 2.

[0112] Furthermore, the conductor 71, which is hollow inside, can be mounted by being fitted into a spacer, a supporter, or the like, placed between the connector 3 and the electronic element 4. In the first embodiment, an example has been described in which the spacer and the supporter placed between the connector 3 and the electronic element 4 are used as the conductor 7, but in the example of the present modified example 2, the length L of the conductor 71 can be adjusted arbitrarily. This makes it easy to adjust the length L of the conductor 71 in accordance with unwanted electromagnetic waves.

[0113] <Effects of the Electronic Device According to Modification 2 of the First Embodiment> As described above, according to electronic device 112 relating to variant example 2 of embodiment 1 of the present disclosure, by providing conductor 71 with a hollow interior, it is possible to reduce the weight of electronic device 112 while improving electromagnetic noise resistance even when electronic element 4 is present in an area where electronic components are densely packed.

[0114] Furthermore, according to electronic device 112 according to modification 2 of embodiment 1 of the present disclosure, by providing conductor 71 with a hollow interior, it is possible to reduce the weight of conductor 71 and improve the long-term reliability of adhesion of conductor 71 to printed wiring board 2. Therefore, even when electronic element 4 is present in an area where electronic components are densely mounted, it is possible to improve the electromagnetic noise resistance of electronic device 120 in the long term.

[0115] Furthermore, in electronic device 112 according to the second modification of the first embodiment of the present disclosure, conductor 71 having a hollow interior makes it easy to mount and adjust conductor 71.

[0116] Variation 3. Next, a third modification of the first embodiment will be described. In the first embodiment, a configuration in which a ground wiring 61 is provided on the surface or inside of the printed wiring board 2 for connecting the conductor 7 to the ground, and a configuration in which a first metal plate (not shown) is provided on the lower part of the printed wiring board 2, has been described. In the third modification, a configuration in which the conductor 7 and the ground are electrically connected via a second metal plate 62 provided on the upper part of the connector 3 or on the opening 11a of the metal housing 1a will be described. Note that the same reference numerals are used for the same components as in the first embodiment, and descriptions of the same or corresponding parts will be omitted. Hereinafter, an electronic device 113 according to a third modification of the first embodiment will be described with reference to the drawings.

[0117] <Configuration of Electronic Device of Modification 3 of First Embodiment> Fig. 10 is a perspective view showing components other than the housing of electronic device 113 according to Variation 3 of Embodiment 1. As shown in Fig. 10, conductor 7 in Variation 3 of Embodiment 1 is connected to second metal plate 62 at FG potential provided on the upper part of connector 3.

[0118] The second metal plate 62 is made of a conductive material with high conductivity, such as copper, nickel, gold, aluminum, silver, tin, or an alloy thereof. In order to reduce manufacturing costs, it is preferable to make the second metal plate 62 from a cheap conductive material.

[0119] The second metal plate 62 is at FG potential like the ground wiring 61 and the first metal plate in the first embodiment. The second metal plate 62 is at FG potential, for example, by electrically connecting it to the metal part of the connector 3, which is at FG potential. The metal part of the connector 3 is at FG potential by connecting it to the shield part of the cable connected to the connector 3. The shield part of the cable is a conductor part that is arranged between the cable wire for transmitting a signal and the coating so as to cover the cable wire in order to prevent noise from being mixed in.

[0120] 10, the second metal plate 62 is provided on the upper part of the connector 3. The conductor 7 is fixed on the second metal plate 62, and the second metal plate 62 and the conductor 7 are electrically connected. Note that the second metal plate 62 does not necessarily have to be provided for the purpose of installing the conductor 7, and may be, for example, a metal plate used for fixing electronic components other than the conductor 7 or for vibration countermeasures for a circuit board.

[0121] The second metal plate 62 does not have to be provided on the connector 3, and may be provided in the opening 11a (see FIG. 7) of the metal housing 1a. In this case, the opening 11a of the metal housing 1a is at the FG potential, and the metal plate 62 electrically connected to the opening 11a of the metal housing 1a is also at the FG potential.

[0122] <Manufacturing Method of Electronic Device of Modification 3 of First Embodiment> The second metal plate 62 and the conductor 7 are fixed to each other by solder or a conductive adhesive. The metal plate 62 and the conductor 7 are electrically connected to each other via the solder or the conductive adhesive.

[0123] <Function of Electronic Device According to Modification 3 of First Embodiment> Conductor 7 functions as a noise suppression component that absorbs unnecessary electromagnetic waves by electrically connecting ground and conductor 7 via second metal plate 62. Conductor 7 can be connected to second metal plate 62 even when it is difficult to connect to ground wiring 61 formed on the surface or inside of printed wiring board 2 and to the first metal plate formed under printed wiring board 2, that is, when an area cannot be secured on printed wiring board 2 for mounting conductor 7 in order to connect to ground.

[0124] <Effects of the Electronic Device of Modification 3 of the First Embodiment> As described above, in electronic device 113 relating to variant example 3 of embodiment 1 of the present disclosure, by providing second metal sheet 62, it is possible to electrically connect conductor 7 to a ground provided on the surface, inside, or bottom of printed wiring board 2, which is a substrate, via second metal sheet 62. Therefore, even when an area for mounting conductor 7 cannot be secured on printed wiring board 2, electromagnetic noise resistance can be improved.

[0125] Embodiment 2 In the third modification of the first embodiment, a configuration was described in which the conductor 7 is electrically connected to a ground provided on the surface, inside, or bottom of the printed wiring board 2 via the second metal plate 62. In the second embodiment, a configuration in which the second metal plate 62 and the conductor 7 are integrally formed will be described. Note that the same components as those in the first embodiment are given the same reference numerals, and descriptions of the same or corresponding parts will be omitted. Also, the circuit of the electronic device 110 according to the first embodiment and the circuit of the electronic device 120 according to the second embodiment are the same, and have a circuit configuration as shown in FIG. 3. Hereinafter, the electronic device 120 according to the second embodiment will be described with reference to the drawings.

[0126] <Configuration of Electronic Device of Second Embodiment> Fig. 11 is a perspective view showing components of electronic device 120 according to embodiment 2 of the present disclosure, excluding the housing, and Fig. 12 is a top view showing components of electronic device 120 according to embodiment 2 of the present disclosure, excluding the housing. As shown in Figs. 11 and 12, conductor 72 corresponding to conductor 7 in embodiment 1 is integrally formed with second metal plate 62. Conductor 72 is planar and has length L from the connection between conductor 72 and second metal plate 62 to the end of conductor 72. Second metal plate 62 serves to electrically connect ground and conductor 72.

[0127] 11 shows an example in which the conductor 72 and the second metal plate 62 have approximately the same thickness. However, the conductor 72 and the second metal plate 62 do not necessarily have to have approximately the same thickness. The conductor 72 is straight and has no bends or folds.

[0128] The second metal plate 62 is at FG potential, similar to the ground wiring 61 in the first embodiment. The second metal plate 62 is at FG potential, for example, by being electrically connected to a metal part of the connector 3, which is at FG potential. The metal part of the connector 3 is at FG potential by being connected to a shield part of a cable connected to the connector 3.

[0129] 11 and 12, the second metal plate 62 and the conductor 72 formed integrally are provided on the upper part of the connector 3. The second metal plate 62 and the conductor 72 formed integrally do not have to be provided on the connector 3, and may be provided in the opening 11a (see FIG. 7) of the metal housing 1a. At this time, the opening 11a of the metal housing 1a is at FG potential, and the metal plate 62 electrically connected to the opening 11a of the metal housing 1a is also at FG potential.

[0130] The second metal plate 62 and the conductor 72 are made of a conductive material with high conductivity, such as copper, nickel, gold, aluminum, silver, tin, or an alloy thereof. To reduce manufacturing costs, it is preferable to make them of a cheap conductive material.

[0131] <Manufacturing method of electronic device according to the second embodiment> Next, a method for manufacturing the electronic device 120 according to the second embodiment of the present disclosure will be described. Note that in this embodiment, only the method for forming the second metal plate 62 and the conductor 72 among the steps for manufacturing the electronic device 120 will be described.

[0132] The second metal sheet 62 and the conductor 72 are formed by cutting a conductive material into an integrated shape of the second metal sheet 62 and the conductor 72. Alternatively, the second metal sheet 62 and the conductor 72 may be formed by punching using a die for forming the integrated shape of the second metal sheet 62 and the conductor 72.

[0133] The second metal plate 62 and the conductor 72 may be formed into an integrated shape by welding the second metal plate 62 and the conductor 72 that have been cut into a predetermined shape in advance.

[0134] <Function of the Electronic Device of the Second Embodiment> Similar to the conductor 7 in the third modification of the first embodiment, the conductor 72 in the second embodiment functions as a noise suppression component that absorbs unnecessary electromagnetic waves by electrically connecting the conductor 72 to the ground via the second metal plate 62. Since the second metal plate 62 and the conductor 72 are integrally formed, the long-term reliability of the electrical connection between the second metal plate 62 and the conductor 72 can be ensured.

[0135] Furthermore, even when it is difficult to connect conductor 72 to ground wiring 61 formed on the surface or inside of printed wiring board 2 and the first metal plate formed on the lower part of printed wiring board 2, that is, when an area cannot be secured on printed wiring board 2 to mount conductor 7 of embodiment 1 in order to connect to ground, it is possible to connect to second metal plate 62.

[0136] Furthermore, by integrally forming the metal plate 62 and the conductor 72, the number of manufacturing steps can be reduced, and therefore the electromagnetic noise resistance of the electronic device 120 can be improved at low cost.

[0137] <Effects of the Electronic Device of the Second Embodiment> As described above, according to electronic device 120 of embodiment 2 of the present disclosure, by integrally forming metal plate 62 at FG potential and conductor 72, it is possible to improve the electromagnetic noise resistance of electronic device 120 even in a case where an electronic element is present in an area where electronic components are densely mounted and an area for mounting conductor 7 cannot be secured to the ground on printed wiring board 2, which is the substrate.

[0138] Furthermore, according to electronic device 120 of embodiment 2 of the present disclosure, by integrally forming metal sheet 62 at FG potential and conductor 72, it is possible to ensure long-term reliability of the electrical connection between metal sheet 62 and conductor 72, and to improve the electromagnetic noise resistance of electronic device 120 in the long term.

[0139] Moreover, according to the electronic device 120 according to the second embodiment of the present disclosure, the electromagnetic noise resistance of the electronic device 120 can be improved at low cost.

[0140] Although the present disclosure has been described based on each embodiment, the present disclosure is not limited to each embodiment. In addition, appropriate combinations, modifications, and omissions of each embodiment are also within the scope of the technical idea of ​​the present disclosure.

[0141] Various aspects of the present disclosure are summarized below as appendices.

[0142] (Appendix 1) A housing and A substrate provided inside the housing; a noise intrusion section provided in the housing, the noise intrusion section being a section through which noise intrudes from the outside of the housing into the inside of the housing; an electronic element provided on the substrate, the voltage of which fluctuates due to noise entering through the noise intrusion portion; a linear conductor provided between the noise intrusion portion and the electronic element and connected to a ground; An electronic device comprising: (Appendix 2) The conductor has a length that is ¼ of the wavelength of the unwanted electromagnetic waves entering through the noise intrusion portion. 2. The electronic device according to claim 1. (Appendix 3) The ground is a conductor having a length from a connection part with the conductor to an outer periphery of the ground that is equal to or greater than ¼ of the wavelength of the unwanted electromagnetic waves entering from the noise intrusion part. 10. The electronic device according to claim 1 or 2. (Appendix 4) The conductor is provided on a straight line connecting the noise intrusion portion and the electronic element. 5. The electronic device according to claim 1, (Appendix 5) The noise intrusion unit is a connector that is connected to an external device via a cable. 5. The electronic device according to claim 1, (Appendix 6) The housing is made of metal, The noise intrusion portion is an opening provided in the housing. 5. The electronic device according to claim 1, (Appendix 7) the connector has a metal part connected to the ground, Further comprising a metal plate electrically connected to the metal portion, The conductor is provided on the metal plate and is electrically connected to the metal portion via the metal plate. 6. The electronic device according to claim 5. (Appendix 8) the connector has a metal part connected to the ground, Further comprising a metal plate electrically connected to the metal portion, The conductor is integrally formed with the metal plate. 6. The electronic device according to claim 5. (Appendix 9) a plurality of the conductors are provided between the noise intrusion portion and the electronic element; The plurality of conductors each have a different length. 10. The electronic device according to claim 1, (Appendix 10) The conductor is hollow inside. 10. The electronic device according to claim 1, [Explanation of symbols]

[0143] 1 Case 1a Metal case 11, 11a opening 2. Printed Wiring Board 3 Connector 30 External Interface 4. Electronic elements 41 Electronic elements 42 Oscillator 5. Integrated Circuits 51 Control Integrated Circuits 52 Memory Integrated Circuits 53 Input / Output Integrated Circuits 54 Power supply integrated circuits 55 Clock Driver Integrated Circuit 61 Ground wiring 62 Second Sheet Metal 7, 71, 72 Conductors

Claims

1. A housing and A substrate provided inside the housing; a noise intrusion section provided in the housing, the noise intrusion section being a section through which noise intrudes from the outside of the housing into the inside of the housing; an electronic element provided on the substrate, the voltage of which fluctuates due to noise entering through the noise intrusion portion; a linear conductor provided between the noise intrusion portion and the electronic element and connected to a ground; An electronic device comprising:

2. The conductor has a length that is ¼ of the wavelength of the unwanted electromagnetic waves entering through the noise intrusion portion.

2. The electronic device according to claim 1.

3. the ground is a conductor having a length from a connection portion with the conductor to an outer periphery of the ground that is equal to or greater than ¼ of the wavelength of the unwanted electromagnetic waves entering from the noise intrusion portion; 2. The electronic device according to claim 1.

4. The conductor is provided on a straight line connecting the noise intrusion portion and the electronic element.

2. The electronic device according to claim 1.

5. The noise intrusion unit is a connector that is connected to an external device via a cable.

2. The electronic device according to claim 1.

6. The housing is made of metal, The noise intrusion portion is an opening provided in the housing.

2. The electronic device according to claim 1.

7. the connector has a metal part connected to the ground, Further comprising a metal plate electrically connected to the metal portion, The conductor is provided on the metal plate and is electrically connected to the metal portion via the metal plate.

6. The electronic device according to claim 5.

8. the connector has a metal part connected to the ground, Further comprising a metal plate electrically connected to the metal portion, The conductor is integrally formed with the metal plate.

6. The electronic device according to claim 5.

9. a plurality of the conductors are provided between the noise intrusion portion and the electronic element; The plurality of conductors each have a different length. The electronic device according to any one of claims 1 to 8.

10. The conductor is hollow inside. The electronic device according to any one of claims 1 to 8.

Images