JP2009199816A - Electronic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electronic apparatus capable of enhancing a shield effect by reducing connection resistance when grounding a connector component to be grounded to a frame of a housing of the apparatus or the like, and being downsized by compactly collecting up conductive members interposed between the connector component to be grounded and the housing of the apparatus. <P>SOLUTION: The electronic apparatus 1 includes a circuit board 4 having a wiring pattern with electronic components 5 mounted thereon, and a connector 2 for transmitting/receiving signals to/from an external apparatus. The electronic apparatus also includes a shielding flexible board 8 for shielding electromagnetic noise generated from the circuit board 4 and the electronic components 5 by covering the circuit board 4 and the electronic components 5. The flexible board 8 is structured to cover the circuit board 4 and the electronic components 5 from both surfaces by being folded back. It is preferable that conductive elastic bodies 9 and 10 electrically connecting the flexible board 8, a metallic shell of the connector 2 and a metallic case of the electronic apparatus 1 to one another are added. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a structure for countermeasures against electromagnetic wave noise in an electronic device, particularly an electronic device having an external input / output interface.

  In an electronic device having an external input / output interface such as USB (Universal Serial Bus), for example, a small portable electronic device such as a camera, in order to perform high-speed signal processing with an external device such as a personal computer or a printer, There is a problem in that electromagnetic noise is generated from an electronic circuit board or circuit components mounted on the circuit board, and this electromagnetic noise is radiated from a connector such as a USB or a cable connected to the connector.

  5 and 6 show examples of conventional electronic devices having a USB connector. Here, a camera which is a small portable electronic device is assumed as the electronic device, FIG. 5 shows a state in which the electronic device is upright, and FIG. 5 and 6, the electronic device 1 includes a USB connector 2 on the side surface. A connector provided at one end of the USB cable 3 is inserted into the USB connector 2 and connected to an external device such as a printer via the cable 3, and signals are exchanged between the external device and the electronic device 1. It is like that.

  As shown in FIG. 7, the electronic device 1 has an internal space formed by joining the rear case 6 and the front case 7 together in a bellows shape, and the electronic circuit board 4 is disposed in the internal space and appropriately fixed. It is fixed to the case by means. The electronic circuit board 4 is made of a hard material, the base portion of the USB connector 2 is fixed to one end, and the conductive portion of the USB connector 2 into which the connector of the cable 3 is inserted is exposed on the side surface of the rear case 6 or the front case 7. Yes. An appropriate number of electronic circuit components 5 are mounted on the electronic circuit board 4, and the USB connector 2 and a part of the electronic circuit components 5 are electrically connected via a circuit pattern or the like formed on the electronic circuit board 4. ing.

  As described above, electromagnetic wave noise is generated in the electronic circuit board 4 and the electronic circuit component 5 mounted thereon. In order to prevent this electromagnetic noise from propagating from the electronic circuit board 4 or the electronic circuit component 5 to other electronic components, electronic circuits, etc., generally, a shield-type sheet metal connected to the circuit board 4 and the ground (GND) is used. It is known to shield the circuit board 4 including the circuit component 5. The shield-type sheet metal has a large volume, and if it is provided in a small device such as a small portable device, the device becomes bulky and the merchantability is reduced.

  Therefore, an elastic and conductive material, such as a conductive sponge, is provided on the metal shell of the USB connector, that is, the outer shell, and the connector shell is connected to the frame constituting the housing of the electronic device via the conductive sponge. And the shell is dropped to the ground. However, according to such a shield structure, it is difficult to reduce the contact resistance between the metal shell of the USB connector and the metal case (housing) of the electronic device, and electromagnetic wave noise is transmitted to the USB cable.

  In addition to what has been described above, various inventions relating to shield structures applicable to electronic devices are described in the patent literature. The invention described in Patent Document 1 is one of them, and a camera capable of arranging a circuit device that easily generates noise and a circuit device that dislikes noise in a shielded state and in a space-efficient state. The assembly structure of electrical components in is described. More specifically, a plate-shaped shield member bent in a crank shape is disposed so as to sew a gap between the circuit device that is partly grounded and easily generates noise and a circuit device that dislikes noise. Thus, the circuit device is cut off between the two circuit devices. And the structure which provided the shield pattern in the range which interrupts | blocks and covers the said both circuit devices is formed by forming the said shield member with a flexible substrate.

  In Patent Document 2, in an electronic device installed outdoors, a LAN connection plug (for example, a product name “Ethernet” plug) insertion opening is formed in a part of a wall constituting a case body, and Ethernet A configuration is disclosed in which a connector is mounted on a printed circuit board at a soldering portion, and a gasket is sandwiched between the Ethernet connector and the wall. The invention described in Patent Document 2 relates to a seal structure for preventing external moisture or the like from entering a cable relay connection room.

  Patent Document 3 describes a connection structure between a board-side connector and a shielded cable-side connector arranged on an electric board. The shielded cable side connector is a metal outer shell member that is in direct contact with the shield material, and the inner side of the outer shell member that is electrically connected to the outer shell member and is electrically connected to the board side connector. A configuration including a metal member is disclosed. The outer shell member is provided with an extended structure portion that is extended so as to be in direct contact with the ground pattern of the electric substrate, and the extended structure portion covers the board-side connector.

Japanese Patent No. 3269717 JP 2007-220375 A Japanese Patent No. 3826054

  The invention described in Patent Document 1 is characterized in that the shield member is formed of a flexible substrate and the space between both circuit devices is covered with the shield member. However, it is basically close to a conventional general shield structure, and a sufficient shielding effect cannot be obtained. In particular, no consideration is given to the shielding effect at the connector portion connected to the external device.

  The invention described in Patent Document 2 relates to a cable repeater for connecting outdoor and indoor devices, and features a seal structure for preventing external moisture and the like from entering the cable relay connection room. Yes. Therefore, there is no direct relationship with a shield structure for shielding electromagnetic wave noise in an electronic device having an external input / output interface as in the present invention.

  The invention described in Patent Document 3 relates to a shield structure in a connector portion that electrically connects an electronic device and an external device. A shielded cable side connector includes a metal outer shell member that directly contacts a shield material. An extension structure extended to directly contact the ground pattern of the substrate is provided. Since the extended structure portion covers the board-side connector, it is considered that the shield effect at the connector portion is high. However, the presence of the extended structure provided in the outer shell member makes the operability at the time of connector connection extremely poor. When connecting the connector with the outer shell member to the mating connector, connect both connectors in a state where the extension structure is bent against the elasticity so that it does not interfere with the mating connector. This is because it is necessary to perform a troublesome operation.

  In addition to the inventions described in the patent documents described above, an object of the present invention is to solve the problem of the shield structure in the connector portion with the outside of a conventional general electronic device. Specifically, when the connector part to be grounded is grounded to the frame of the housing of the device, the connection resistance can be reduced to enhance the shielding effect, and the connector component and the device to be grounded It is an object of the present invention to provide an electronic device that can be made compact by making it possible to compactly combine conductive members interposed between the frame of the housing and the like.

  The present invention relates to a circuit board having a printed wiring pattern on which an electronic component is mounted, and an electronic apparatus having a connector that exchanges signals with an external device, and the circuit board covers the circuit board and the electronic component. The most important feature is that it has a flexible substrate for shielding that shields electromagnetic noise from electronic components.

The flexible substrate may be configured to cover the circuit board and the electronic component from both sides by being folded.
A conductive elastic body that electrically connects the flexible substrate to the metal shell of the connector and the metal case of the electronic device may be added.

  Since the flexible board for shielding is provided to cover the circuit board and the electronic component, even if the electronic device has no room in the internal space, the electromagnetic wave emitted from the circuit board and the electronic component by the arrangement of the flexible board for shielding Noise can be effectively shielded, and the electronic device can be made compact while enhancing the shielding effect.

If the circuit board and the electronic component are covered from both sides by folding the flexible substrate, electromagnetic wave noise emitted from the circuit board and the electronic component can be effectively blocked from being radiated to the outside.
By adding a conductive elastic body that electrically connects the flexible board to the metal shell of the connector and the metal case of the electronic device, the shield pattern of the flexible board, the metal shell of the connector, and the metal case of the electronic device can be made small. The contact resistance can connect to the metal case of the electronic device, and the shielding effect by the flexible substrate can be further enhanced.

  Embodiments of an electronic apparatus according to the present invention will be described below with reference to FIGS. 1 to 4 are examples of a camera which is a small portable electronic device, and shows a face down state, that is, a state in which the front face is directed downward. Components and components that are substantially the same as those of the conventional example shown in FIGS. 5 to 7 are denoted by the same reference numerals.

  1 and 2, the electronic device 1 includes a USB connector 2 on the side surface as an input / output interface with an external device. A connector provided at one end of the USB cable 3 is inserted into the USB connector 2 and connected to an external device such as a printer via the cable 3, and signals are exchanged between the external device and the electronic device 1. It is like that.

  In the electronic device 1, an inner space is formed by joining the rear case 6 and the front case 7 to each other, and the electronic circuit board 4 is disposed in the inner space and is fixed to the case by appropriate fixing means. Yes. The circuit board 4 is made of a hard synthetic resin material, the base of the USB connector 2 is fixed to one end of the circuit board 4, and the conductive part of the USB connector 2 into which the connector of the cable 3 is to be inserted is the rear case 6 or the front case 7. It is exposed on the side. The base portion of the USB connector 2 is a metal outer shell, that is, a metal shell. An appropriate number of electronic circuit components 5 are mounted on the circuit board 4, and the USB connector 2 and a part of the circuit components 5 are electrically connected via a circuit pattern or the like formed on the circuit board 4. The configuration described so far is substantially the same as the configuration of the conventional example.

  In the internal space of the electronic device 1 formed by the rear case 6 and the front case 7, a shield flexible substrate 8 that blocks electromagnetic wave noise from the circuit board 4 and the electronic component 5 is disposed. The flexible substrate 8 has a conductive pattern for shielding and is folded back in a U shape so as to include the connector 2 metal shell portion and cover the circuit substrate 4 from both sides in the vertical direction. Therefore, the flexible substrate 8 has an area necessary for covering the circuit substrate 4 from both sides in the vertical direction. The flexible substrate 8 is covered with an insulating layer on both sides except an appropriate number of connection pads 81 and 82. An appropriate number of connection pads 41 and 42 are also formed on the circuit board 4. The connection pads 81 and 82 of the flexible substrate 8 are formed at positions facing the connection pads 41 and 42 of the circuit board 4 and positions facing the metal shell of the USB connector 2 fixed to the circuit board 4. .

  The flexible substrate 8, the metal shell of the connector 2, and the metal case of the electronic device, that is, the rear case 6 and the front case 7, are electrically connected, and the flexible substrate 8 and the metal shell of the connector 2 are grounded to the metal case. The specific structure of these electrical connections is as follows. As shown in FIGS. 2 and 3, there is no electrical conduction between one connection pad formed on the upper surface of the upper portion of the flexible substrate 8 that is folded up and down and the inner surface of the rear case 6. The elastic substrate 10 is interposed, and the flexible substrate 8 and the metal case are electrically connected. Further, a conductive elastic body 9 is interposed between a connection pad formed on the lower surface of the upper portion of the flexible substrate 8 so as to face the metal shell of the connector 2 and the metal shell of the connector 2. The flexible substrate 8 and the metal shell of the connector 2 are electrically connected. These conductive elastic bodies 10 and 9 are made of, for example, a conductive sponge. In the illustrated example, the conductive sponge is formed in a rectangular parallelepiped shape.

  1 to 3, the rear case 6, the upper and lower portions of the flexible substrate 8, the circuit board 4, and the front case 7 are separated from each other, and the conductive elastic bodies 10 and 9 are respectively connected to the rear case 6 and the connector 2. A state of being separated from the metal shell is shown. FIG. 4 shows a state in which the rear case 6 and the front case 7 are coupled in a bellows shape, and the flexible substrate 8, the circuit substrate 4, and the like are incorporated in the internal space formed by these cases 6 and 7. Yes. In the embodiment shown in FIG. 4, the conductive elastic body 10 is compressed between the inner surface of the rear case 6 and one of the connection pads of the flexible substrate 8, and the shield pattern of the rear case 6 and the flexible substrate 8 is electrically connected. Has been. Further, the conductive elastic body 9 is compressed between another one of the connection pads of the flexible substrate 8 and the metal shell of the connector 2, and the shield pattern of the flexible substrate 8 is electrically connected to the metal shell of the connector 2. ing.

  Although not shown in FIGS. 3 and 4, another connection pad formed on the upper and lower surfaces of the upper portion of the flexible substrate 8 and a connection pad on the upper surface side of the rear case 6 and the circuit board 4 You may interpose in the state which compressed the electroconductive elastic body between each, respectively. Similarly, the conductive elastic body is compressed between another connection pad formed on the upper and lower surfaces of the lower portion of the flexible substrate 8 and the connection pads on the lower surface side of the front case 7 and the circuit board 4. You may interpose in the state. By doing so, the metal case and the flexible substrate 8 for shielding can be connected with a smaller contact resistance, and the shielding effect by the flexible substrate 8 can be further enhanced.

  According to the embodiment described above, the electromagnetic wave noise emitted from the circuit board 4 and the circuit components mounted on the circuit board 4 is provided by the shielding flexible board 8 arranged so as to cover the circuit board 4 from both sides. It is shielded and electromagnetic noise is prevented from being radiated to the outside. In addition, since the metal shell of the USB connector 2 is grounded to the flexible board through the conductive elastic body, and further from the flexible board to the metal case, electromagnetic wave noise emitted from the circuit board 4 and the circuit components is detected by the USB connector. 2 is prevented from being released to the outside. On the other hand, electromagnetic noise that tries to enter from the outside is blocked by the USB connector 2.

According to the said Example, the following effects other than said effect can be acquired.
1. The flexible substrate 8 can be used as a shielding material even in a small form device with little space, and thus electromagnetic wave noise from the circuit board 4 and the electronic component 5 can be effectively blocked.
2. The conductive elastic bodies 9 and 10 are used in combination with the flexible substrate 8 and are overlapped to ground the flexible substrate 8 to the metal case and to ground the metal shell of the connector 2, so that the circuit board 4 Since the electromagnetic wave noise from the component 5 is shielded, the contact area between the conductive elastic body and the flexible substrate 8 and the metal case is increased by compressing the conductive elastic body. Metal cases can be connected by the shortest path. As a result, the contact resistance between the flexible substrate 8 and the metal case and the contact resistance between the flexible substrate 8 and the metal shell of the connector 2 can be reduced, and the USB cable 3 connected to the connector 2 (see FIGS. 1 and 2). It is possible to prevent electromagnetic wave noise from being transmitted. As a result, it is possible to simultaneously shield electromagnetic waves generated by the circuit board 4 and the electronic component 5 and to prevent electromagnetic noise from entering and exiting via the USB cable and the USB connector performing high-speed communication.

  For the above example, the noise margin (dBuV) was measured by an EMI test which is a predetermined standard. The EMI test is performed by standing an antenna at a location 10 m away from the electronic device that is the subject and measuring the electromagnetic wave entering the antenna while the electronic device is in operation. As a standard, the electromagnetic wave intensity must be 30 dB or less from 30 MHz to 230 MHz and 37 dB or less from 230 MHz to 1000 MHz. In measuring, the electronic device is placed at a position of 80 cm height of the turntable that rotates 360 degrees, the turntable is rotated while operating the electronic device, and the orientation of the biconical antenna is horizontal (HOR) or vertical (VER) Find the location with the strongest electromagnetic wave and record the intensity of the electromagnetic wave. Conforming standards include VCCI (Japan), FCC (US), EN55022 (Europe) based on the information processing standard (CISPR22) defined by the International Special Committee on Radio Interference.

  Table 1 shows the results of the EMI test of the example. For comparison, when there is no shield flexible substrate, when only a shield flexible substrate is provided, when a shield flexible substrate and two conductive sponges as a conductive elastic body are used as shown in FIG. The measured value is shown. The numerical value is a margin value (dBuV) with respect to the standard. “−” Indicates that there is no noise peak.

Table 1

  As is apparent from Table 1, it can be seen that the noise margin is increased by using the shield flexible substrate as in the present invention. Furthermore, it can be seen that the noise margin is further increased by using a flexible substrate for shielding and two conductive sponges as conductive elastic bodies.

It is a disassembled perspective view from the rear surface side which shows the Example of the electronic device concerning this invention. It is a disassembled perspective view from the rear surface side which shows the example which added the electroconductive elastic body to the said electronic device. It is a decomposition | disassembly bottom view which shows the example of the electronic device which added the said conductive elastic body. It is a bottom view which shows the example of the final assembly of the electronic device which added the said conductive elastic body. It is the perspective view seen from the back side which shows the example of the conventional electronic device. It is a perspective view shown in the state where the conventional example of the above-mentioned electronic device was turned down. It is a disassembled perspective view shown in the state which turned down the prior art example of the said electronic device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electronic device 2 Connector 3 Cable 4 Circuit board 41 Connection pad 42 Connection pad 5 Electronic component 6 Rear case 7 Front case 8 Flexible board 81 Connection pad 82 Connection pad 9 Conductive elastic body 10 Conductive elastic body

Claims (8)

A circuit board having a printed wiring pattern on which electronic components are mounted, and an electronic device having a connector for exchanging signals with an external device,
An electronic device having a flexible substrate for shielding that shields electromagnetic wave noise from the circuit board and the electronic component by covering the circuit board and the electronic component.   The electronic device according to claim 1, wherein the flexible substrate is folded to cover the circuit substrate and the electronic component from both sides.   The electronic device according to claim 1, wherein the flexible substrate, the metal shell of the connector, and the metal case of the electronic device are electrically connected. A circuit board having a printed wiring pattern on which electronic components are mounted, and an electronic device having a connector for exchanging signals with an external device,
A flexible substrate that blocks electromagnetic wave noise from the circuit board and the electronic component by covering the circuit board and the electronic component;
A conductive elastic body for electrically connecting the flexible substrate and the metal shell of the connector and the metal case of the electronic device;
Having electronic equipment.   The electronic device according to claim 4, wherein the flexible substrate is folded back to cover the circuit substrate and the electronic component from both sides.   The electronic device according to claim 4, wherein the conductive elastic body is interposed between the flexible substrate, the metal shell of the connector, and the metal case of the electronic device in a compressed state.   The flexible substrate has connection pads on both sides, and a conductive elastic body is interposed between one connection pad and the metal shell of the connector, and between the other connection pad and the metal case of the electronic device. The electronic device according to claim 4, 5 or 6.   The electronic device according to claim 6, wherein the flexible substrate has a shielding pattern covered with an insulating layer except for a connection pad portion.

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