JP2022127586A - Communication module and electronic apparatus - Google Patents

Abstract

To reduce radiation noise.SOLUTION: A rigid wiring board 101 has a plurality of signal lines 111 and a ground line 120. A flexible wiring board 200 has a conductor layer 201 including a plurality of signal lines 212 and a conductor layer 202 including a shield member 210. The plurality of signal lines 111 and the plurality of signal lines 212 are electrically connected with each other with a plurality of signal terminals 901. A connection member 902 being a conductive member is provided between the ground line 120 and the shield member 210. The connection member 902 is arranged to partially overlap at least one of the plurality of signal lines 212 when seen in a Z direction.SELECTED DRAWING: Figure 5

Description

The present invention relates to noise countermeasure technology.

2. Description of the Related Art Electronic devices such as digital multi-function peripherals and digital cameras have a communication module that includes two electronic units that transmit data using digital signals. A signal line used for data transmission between two electronic units carries a current of a digital signal to be transmitted. Radiation noise such as electric field noise may occur due to the current flowing through the signal line. When radiation noise interferes with a component in an electronic device, there is a risk that the component or another component via the component may malfunction.

On the other hand, Japanese Patent Application Laid-Open No. 2002-200000 discloses that a part of the ground line of a flexible wiring board is exposed from an insulating material and a part of the ground line is electrically connected to a conductor as a noise countermeasure.

JP 2007-243091 A

However, even if noise countermeasures such as those disclosed in Japanese Patent Laid-Open No. 2002-200310 are taken, radiation noise is unavoidably generated from the communication module, and further reduction of radiation noise has been demanded.

An object of the present invention is to reduce radiation noise.

One aspect of the present invention is a first wiring board having a plurality of first signal lines and a first ground line, a first layer including a plurality of second signal lines, and a second layer including a shield member. 2 wiring boards, a plurality of first connection members for electrically connecting the plurality of first signal lines and the plurality of second signal lines, respectively, and provided between the first ground line and the shield member and at least one electrically conductive member that is connected to at least one of the plurality of second signal lines when viewed in a direction perpendicular to the main surface of the first wiring board. The communication module is characterized in that it is arranged so as to partially overlap the two signal lines.

According to the present invention, radiation noise is reduced.

1A and 1B are perspective views of an imaging device that is an example of an electronic device according to a first embodiment; FIG. 2A and 2B are perspective views showing the device main body of the imaging device according to the first embodiment; FIG. 2 is a block diagram of the device main body of the imaging device according to the first embodiment; FIG. 1 is an explanatory diagram showing a schematic configuration of part of an apparatus body of an imaging apparatus according to a first embodiment; FIG. 1A is a plan view showing a part of a rigid wiring board and a connection structure according to the first embodiment; FIG. (b) is a plan view showing a part of the flexible wiring board and the connection structure according to the first embodiment. (c) is a cross-sectional view of the rigid wiring board, the flexible wiring board, and the connection structure according to the first embodiment. (a) is an explanatory diagram of the flow of a return current in the first embodiment. (b) is an explanatory diagram of the flow of the return current in the comparative example. 3(a) to 3(c) are explanatory diagrams of the configuration used in the simulation of Example 1. FIG. 5 is a graph showing simulation results of electric field intensity of electric field noise in Example 1. FIG. (a) is a plan view showing a portion of a rigid wiring board and a connection structure according to a second embodiment. (b) is a plan view showing a portion of a flexible wiring board and a connection structure according to a second embodiment; (c) is a cross-sectional view of a rigid wiring board, a flexible wiring board, and a connection structure according to a second embodiment. (a) is a plan view showing a portion of a rigid wiring board and a connection structure according to a third embodiment. (b) is a plan view showing a portion of a flexible wiring board and a connection structure according to a third embodiment; (c) and (d) are cross-sectional views of a rigid wiring board, a flexible wiring board, and a connection structure according to a third embodiment. (a) is a plan view showing a portion of a rigid wiring board and a connection structure according to a fourth embodiment. (b) is a plan view showing a portion of a flexible wiring board and a connection structure according to a fourth embodiment; (c) is a cross-sectional view of a rigid wiring board, a flexible wiring board, and a connection structure according to a fourth embodiment. (a) is a plan view showing a portion of a rigid wiring board and a connection structure of a modification. (b) is a plan view showing a part of a flexible wiring board and a connection structure of a modification. (c) is a cross-sectional view of a rigid wiring board, a flexible wiring board, and a connection structure of a modification. (a) is a plan view showing a portion of a rigid wiring board and a connection structure according to a fifth embodiment. (b) is a plan view showing a portion of a flexible wiring board and a connection structure according to a fifth embodiment; (c) is a cross-sectional view of a rigid wiring board, a flexible wiring board, and a connection structure of a modification according to the fifth embodiment. FIG. 9 is a schematic diagram showing a measurement system for measuring reception sensitivity in Example 2; (a) and (b) are schematic diagrams showing a measurement system for measuring reception sensitivity in Example 2. FIG. FIG. 5 is a cross-sectional view showing the structure of a flexible wiring board in Example 2; (a) to (c) are schematic diagrams for explaining the measurement conditions of Example 2. FIG. (a) and (b) are schematic diagrams for explaining the measurement conditions of Example 2. FIG. 9 is a graph showing the results of measuring the interference amount of electric field noise in Example 2. FIG.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings.

[First embodiment]
FIGS. 1A and 1B are perspective views of an imaging device 1000, which is an example of electronic equipment according to the first embodiment. FIG. 1A is a perspective view of the imaging device 1000 as seen from the liquid crystal screen 1301 side. FIG. 1B is a perspective view of the imaging device 1000 as viewed from the lens barrel 1302 side. The imaging device 1000 is a digital camera and has a function of capturing still images and/or moving images. The imaging device 1000 has a housing 1001 that is an exterior case, a liquid crystal screen 1301 provided on the housing 1001 , and a grip 1304 provided on the housing 1001 . A grip 1304 is provided with a shutter button 1303 . A lens barrel 1302 is detachable from the housing 1001 .

A memory connector 702 having a slot 702A is arranged inside the housing 1001 . A memory card M1 such as an SD card or a CF card can be inserted into and removed from the slot 702A of the memory connector 702. FIG. By removing the lid (not shown) from the housing 1001, the slot 702A of the memory connector 702 is exposed to the outside of the housing 1001. FIG. By inserting the memory card M1 into the slot 702A, image data obtained by imaging can be written to the memory card M1, and image data written to the memory card M1 can be read.

FIGS. 2A and 2B are perspective views showing an apparatus main body 1500, which is an internal structure arranged inside a housing 1001 of the imaging apparatus 1000 according to the first embodiment. FIG. 3 is a block diagram of the device main body 1500 according to the first embodiment. The imaging device 1000 includes a housing 1001 and a device body 1500 arranged inside the housing 1001 . 2(a) is a perspective view of the device main body 1500 viewed from the same direction as FIG. 1(a), and FIG. 2(b) is a perspective view of the device main body 1500 viewed from the same direction as FIG. 1(b). It is a diagram.

The device main body 1500 has an imaging unit 100 , an image processing unit 300 , a wireless communication unit 500 and an accessory unit 700 . The image processing unit 300 is electrically connected to the imaging unit 100, the wireless communication unit 500, and the accessory unit 700 so that they can communicate with each other.

A support member 1008 made of resin or metal is arranged inside the housing 1001 , and the imaging unit 100 , the image processing unit 300 , the wireless communication unit 500 , and the accessory unit 700 are supported by the support member 1008 . ing. The imaging unit 100 is arranged on the side of the lens barrel 1302 shown in FIG. 1B with respect to the support member 1008 . The image processing unit 300 is fixed to a support member 1008 with a fixing member 1005 such as a screw.

The imaging unit 100 includes a rigid wiring board 101 that is an example of a first wiring board, an image sensor 102 mounted on the rigid wiring board 101 , and a connector 103 mounted on the rigid wiring board 101 . The rigid wiring board 101 is a printed wiring board, that is, a rigid printed wiring board. The image sensor 102 is a semiconductor device that is an example of an electronic component. Image sensor 102 is an image sensor such as a CMOS image sensor or a CCD image sensor. The image sensor 102 photoelectrically converts an incident optical image and outputs a data signal, which is a digital signal representing a captured image. The connector 103 is electrically connected to the image sensor 102 by wiring of the rigid wiring board 101 .

The image processing unit 300 has a rigid wiring board 301 which is an example of a wiring board, and an image processing IC 302 mounted on the rigid wiring board 301 . The rigid wiring board 301 is a printed wiring board, that is, a rigid printed wiring board. The image processing IC 302 is a semiconductor device that is an example of an electronic component. The image processing unit 300 also has connectors 303 , 304 , and 305 electrically connected to the image processing IC 302 mounted on the rigid wiring board 301 by wiring of the rigid wiring board 301 .

The wireless communication unit 500 is capable of wireless communication with an external device such as a PC or a wireless router. A wireless communication unit 500 includes a rigid wiring board 501 that is an example of a wiring board, and a wireless communication IC 502 mounted on the rigid wiring board 501 . The rigid wiring board 501 is a printed wiring board, that is, a rigid printed wiring board. A rigid wiring board 501 has an antenna 503 configured by a conductor pattern or the like. The wireless communication unit 500 also has a connector 504 electrically connected to the wireless communication IC 502 mounted on the rigid wiring board 501 by wiring of the rigid wiring board 501 .

A wireless communication IC 502 is an IC capable of transmitting and/or receiving data to and from an external device via an antenna 503 . For example, the wireless communication IC 502 modulates a digital signal representing image data and transmits it from the antenna 503 as radio waves at a communication frequency of wireless standards. Also, for example, the wireless communication IC 502 demodulates radio waves received by the antenna 503 into digital signals representing image data. The communication frequency is a frequency in the GHz band, which is a frequency of 1 GHz or higher, such as a frequency in the 2 GHz band or the 5 GHz band. Here, the 2 GHz band is a frequency range from 2.4 GHz to 2.5 GHz. Also, the 5 GHz band is a frequency range from 5.2 GHz to 5.8 GHz.

The wireless communication unit 500, that is, the wireless communication IC 502, is configured to wirelessly communicate with an external device in compliance with wireless communication standards. The wireless communication standard is, for example, the WiFi (registered trademark) standard or the Bluetooth (registered trademark) standard.

The accessory unit 700 has a rigid wiring board 701 which is an example of a wiring board, and the above-described memory connector 702 mounted on the rigid wiring board 701 . The rigid wiring board 701 is a printed wiring board, that is, a rigid printed wiring board. The accessory unit 700 also has a memory connector 702 mounted on the rigid wiring board 701 and a connector 703 electrically connected by the wiring of the rigid wiring board 701 .

The imaging unit 100 and the image processing unit 300 are communicably connected to each other by a flexible wiring board 200, which is an example of a second wiring board. Flexible wiring board 200 is a printed wiring board, that is, a flexible printed wiring board. The image processing unit 300 and the wireless communication unit 500 are communicably connected to each other via a harness 400 . The image processing unit 300 and the accessory unit 700 are connected by a harness 600 so as to be able to communicate with each other. A first longitudinal end of flexible wiring board 200 is attached to connector 103 of imaging unit 100 , and a second longitudinal end of flexible wiring board 200 is attached to connector 303 of image processing unit 300 . A first longitudinal end of harness 400 is attached to connector 304 of image processing unit 300 , and a second longitudinal end of harness 400 is attached to connector 504 of wireless communication unit 500 . A first longitudinal end of the harness 600 is attached to the connector 305 of the image processing unit 300 , and a second longitudinal end of the harness 600 is attached to the connector 703 of the accessory unit 700 . The harness 400 may be a flexible printed wiring board, and the harness 600 may be a flexible printed wiring board.

In the first embodiment, as shown in FIG. 3, a communication module 800 is configured with an imaging unit 100, an image processing unit 300, and a flexible wiring board 200. FIG. The imaging unit 100 is an example of a first electronic unit, and the image processing unit 300 is an example of a second electronic unit. The imaging unit 100 and the image processing unit 300 are connected by a flexible wiring board 200 so as to perform data transmission in the form of digital signals. For example, the image sensor 102 of the imaging unit 100 can transmit digital signals, which are data signals, to the image processing IC 302 of the image processing unit 300 via the flexible wiring board 200 .

A data signal communicated between the imaging unit 100 and the image processing unit 300 through the flexible wiring board 200 is a digital signal with a transmission rate of 1 Gbps or higher. The data signal is a digital signal of image data in the first embodiment. A digital signal transmitted via flexible wiring board 200 may be either a single-ended signal or a differential signal, but is preferably a differential signal that enables faster transmission than a single-ended signal. . In the first embodiment, the digital signal transmitted from the imaging unit 100 to the image processing unit 300 via the flexible wiring board 200 is a differential signal.

The image processing IC 302 can acquire a digital signal, which is an electrical signal representing a captured image, from the image sensor 102 and perform image processing. The image processing IC 302 can also perform processing of writing image data to the memory card M1 and processing of reading image data from the memory card M1. Furthermore, the image processing IC 302 can perform processing for acquiring image data from the wireless communication IC 502 and processing for sending image data to the wireless communication IC 502 .

The flexible wiring board 200 includes signal lines used for transmitting data signals, that is, data signal lines. Furthermore, flexible wiring board 200 may include wiring other than data signal lines, such as control lines, power lines, and ground lines. Note that another signal may be added to the data signal transmitted through the data signal line. Another signal is, for example, a synchronization signal.

FIG. 4 is an explanatory diagram showing a schematic configuration of part of the apparatus main body 1500 according to the first embodiment. When transmitting a digital signal using flexible wiring board 200, flexible wiring board 200 is provided in order to reduce noise emitted from flexible wiring board 200 or to reduce external noise superimposed on the digital signal. A shield member 210 is included. An image sensor 102 (FIG. 2(b)) and a connector 103 are mounted on the main surface 101A of the rigid wiring board 101. As shown in FIG. A flexible wiring board 200 is attached to the connector 103 . Here, the direction perpendicular to the main surface 101A is defined as the Z direction. The directions crossing the Z direction are defined as the X direction and the Y direction. The X and Y directions are preferably orthogonal to the Z direction. Moreover, the Y direction is a direction that crosses the X direction, and is preferably orthogonal to the X direction.

FIG. 5A is a plan view showing a portion of rigid wiring board 101 and a connection structure according to the first embodiment. FIG. 5(b) is a plan view showing a portion of the flexible wiring board 200 and the connection structure according to the first embodiment. FIG. 5(c) is a sectional view of the rigid wiring board 101, the flexible wiring board 200, and the connection structure according to the first embodiment. FIG. 5(c) schematically shows a cross section along line VC-VC shown in FIGS. 5(a) and 5(b).

Rigid wiring board 101 is a printed wiring board having at least one conductor layer, conductor layer 1011 in the first embodiment. A conductor layer is a layer on which a conductor pattern is arranged. The conductor layer 1011 is an outer layer, ie, a surface layer. Conductive layer 1011 corresponds to main surface 101A shown in FIG.

A solder resist 105 is arranged on the conductor layer 1011 . Rigid wiring board 101 has insulator 110 which is an insulating substrate, a plurality of signal lines 111 , and ground line 120 . In the first embodiment, the number of signal lines 111 is six. Each signal line 111 and ground line 120 is made of a conductive member, that is, a metal. A part or the whole of each signal line 111 is arranged on the conductor layer 1011 . Also, part or all of the ground line 120 is arranged on the conductor layer 1011 . A ground potential is applied to the ground line 120 as a reference for each part. For example, the ground line 120 is electrically connected to the negative pole of a battery (not shown).

Each signal line 111 is a first signal line. Each signal line 111 includes a conductor pattern 1111 arranged on the conductor layer 1011 and extending in the longitudinal direction, which is the wiring direction. The conductor pattern 1111 is an example of a first conductor pattern and an example of a first signal pattern. Ground line 120 is the first ground line. The ground line 120 includes a solid conductor pattern 1200 arranged on the conductor layer 1011 . Conductive pattern 1200 is an example of a first ground pattern. Of the plurality of signal lines 111, two signal lines 111 adjacent to each other form a differential pair wiring, which is a transmission line for transmitting differential signals. In the first embodiment, six signal lines 111 constitute three differential pair wirings.

The first end in the longitudinal direction of the flexible wiring board 200 is the end 231 in the X direction in the example of FIGS. 5(b) and 5(c). An end portion 231 of flexible wiring board 200 is attached to connector 103 . The flexible wiring board 200 is a two-layer flexible printed wiring board having two conductor layers 201 and 202 spaced apart in the thickness direction, the Z direction in the example of FIG. be. That is, the conductor layer 201 and the conductor layer 202 are arranged adjacent to each other in the Z direction with the insulator 205 interposed therebetween.

The conductor layer 201 is an example of a first layer, and the conductor layer 202 is an example of a second layer. The conductor layer 202 is another conductor layer different from the conductor layer 201 . Flexible wiring board 200 has a plurality of signal lines 212 and at least one ground line arranged on conductor layer 201 . In the first embodiment, the at least one ground line is the plurality of ground lines 220 . Also, in the first embodiment, the number of signal lines 212 is six, which is the same as the number of signal lines 111 . Six signal lines 212 constitute three differential pair wirings. The number of ground lines 220 is two. Each signal line 212 and each ground line 220 is made of a conductive material, that is, a metal.

Each signal line 212 is a second signal line. Each signal line 212 is an example of a conductor pattern extending in the longitudinal direction and is an example of a second signal pattern. Each ground line 220 is a second ground line. Each ground line 220 is an example of a conductor pattern extending in the longitudinal direction and an example of a second ground pattern.

The plurality of signal lines 212 and the plurality of ground lines 220 are arranged at intervals in a predetermined direction, which is the Y direction in the example shown in FIG. 5B. That is, in the example shown in FIG. 5B, the predetermined direction is the Y direction. The predetermined direction is also the width direction of the flexible wiring board 200 , that is, the width direction of each of the plurality of signal lines 212 . Therefore, the length of the signal line 212 in the Y direction can also be said to be the width of the signal line 212 in the Y direction.

The plurality of signal lines 212 and the plurality of ground lines 220 are formed extending in the longitudinal direction, that is, in the X direction in the example shown in FIG. 5B. The six signal lines 212 are arranged adjacent to each other while being spaced apart from each other in the Y direction. The two ground lines 220 are spaced apart from the two signal lines 212 located at both ends in the Y direction so as to sandwich the six signal lines 212 in the Y direction. Note that the arrangement order of the signal lines 212 and the ground lines 220 is not limited to this. A ground line may be arranged between a plurality of signal lines 212, such as between differential pair wirings, for example. The differential pair wiring in this case is a pair of signal lines 212 adjacent to each other.

A shield member 210 is arranged on the conductor layer 202 . The shield member 210 is a conductor pattern made of a member having conductivity, and is arranged on the conductor layer 202 so as to be exposed to the outside. A part of each signal line 212 and a part of each ground line 220 are exposed to the outside at an end portion 231 of the flexible wiring board 200 so as to be attachable to the connector 103 . That is, the shield member 210 is not arranged on the wiring at the end portion 231 . In the flexible wiring board 200, the end portion opposite to the end portion 231, that is, the end portion attached to the connector 303 shown in FIG.

Connector 103 mounted on rigid wiring board 101 has a plurality of signal terminals 901 and a plurality of ground terminals 903 . The plurality of signal terminals 901 and the plurality of ground terminals 903 are arranged in a line with an interval in the Y direction.

Each signal terminal 901 is an example of a first connection member. Each ground terminal 903 is an example of a ground connection member and an example of a second connection member. The plurality of signal terminals 901 are electrically and mechanically connected to the plurality of signal lines 111 with a bonding material such as solder. The plurality of ground terminals 903 are both electrically and mechanically connected to the ground wire 120 with a bonding material such as solder. By attaching the end portion 231 of the flexible wiring board 200 to the connector 103 , the plurality of signal lines 111 of the rigid wiring board 101 and the plurality of signal lines 212 of the flexible wiring board 200 are connected to the plurality of signal terminals 901 of the connector 103 . They are electrically connected to each other. Also, by attaching the end portion 231 of the flexible wiring board 200 to the connector 103 , the ground line 120 of the rigid wiring board 101 and the plurality of ground lines 220 of the flexible wiring board 200 are electrically connected to the plurality of ground terminals 903 of the connector 103 . connected In the first embodiment, since the flexible wiring board 200 is detachable from the connector 103 , the flexible wiring board 200 is detachably connected to the rigid wiring board 101 via the connector 103 including a plurality of signal terminals 901 .

A data signal representing an image generated by the image sensor 102 is transmitted as a differential signal to the image processing IC 302 via a pair of signal lines 111, a pair of signal terminals 901, and a pair of signal lines 212. FIG.

Here, in the shield member 210 of the flexible wiring board 200 , a return current for the digital signal current flowing through each signal line 212 flows. Each signal line 212 includes a portion 2121 facing the shield member 210 in the Z direction, which is the thickness direction. A portion 2121 is a portion other than the pair of ends. One of the pair of ends is the end 231 . A portion 2121 in each signal line 212 is a portion hidden by the shield member 210 in FIG. 5(b). Since the current of the digital signal flowing through the portion 2121 of each signal line 212 and the return current flowing through the shield member 210 are close to each other, the electric fields generated by the respective currents cancel each other, and radiation noise from each signal line 212 is reduced. can be effectively reduced.

On the other hand, connector 103 does not have shield member 210 of flexible wiring board 200 . Therefore, in the first embodiment, communication module 800 is provided with at least one terminal between rigid wiring board 101 and flexible wiring board 200 in order to secure the path of the return current flowing through shield member 210 of flexible wiring board 200 . It has two conductive members. In a first embodiment, the at least one conductive member is one connecting member 902 . The material of the connection member 902 is a material having conductivity, that is, a metal. For example, the connecting member 902 can be a metal gasket. Connection member 902 electrically connects ground line 120 of rigid wiring board 101 and shield member 210 of flexible wiring board 200 . The closer the connection member 902 is to the connector 103 , the better, in order to distribute the return current in the connector 103 to the connection member 902 .

An opening 1051 is formed in solder resist 105 of rigid wiring board 101 , and portion 1201 of ground line 120 is exposed from opening 1051 . Connection member 902 contacts portion 1201 of ground line 120 through opening 1051 of solder resist 105 . Flexible wiring board 200 is attached to connector 103 so that shield member 210 faces portion 1201 of ground line 120 of rigid wiring board 101 . A connection member 902 provided on the portion 1201 of the ground line 120 contacts the shield member 210 .

At least one of ground line 120 of rigid wiring board 101 and shield member 210 of flexible wiring board 200 is preferably connected to connecting member 902 with a conductive double-sided adhesive tape. When one of the ground wire 120 and the shield member 210 and the connection member 902 are connected with a conductive double-sided adhesive tape, the other of the ground wire 120 and the shield member 210 and the connection member 902 are connected by soldering or the like. may be joined with a joining material. Also, the connection member 902 itself may be a conductive double-sided adhesive tape.

FIG. 6A is an explanatory diagram of the return current flow in the first embodiment. FIG. 6B is an explanatory diagram of the return current flow in the comparative example. The comparative example shown in FIG. 6(b) shows a state in which the connecting member 902 is omitted from FIG. 6(a). 6A and 6B, illustration of the insulator 205 of the flexible wiring board 200 is omitted.

Without connection member 902 as in the comparative example shown in FIG. At the frequency corresponding to the transmission rate of the digital signal transmitted through flexible wiring board 200 and in the vicinity of that frequency, the level of conduction noise superimposed on the digital signal tends to increase. In flexible wiring board 200, radiation noise can be reduced by canceling out the electric field generated by the signal current containing conduction noise and the electric field generated by the return current. However, in the comparative example shown in FIG. 6B, the return current flowing through shield member 210 concentrates on ground terminal 903 of connector 103 . Therefore, in the connector 103 and in the vicinity of the connector 103, the effect of canceling out the electric field generated by the signal current including conduction noise and the electric field generated by the return current is reduced. Accordingly, in the comparative example, the level of electric field noise radiated from the connector 103 and the vicinity of the connector 103 tends to be high. If electric field noise radiated from the connector 103 and its vicinity interferes with the wireless communication unit 500, the wireless communication unit 500 may malfunction. For example, in a digital signal, when a common mode component with a frequency of 2.4 GHz or 5 GHz used in wireless communication of the wireless communication unit 500 or a frequency in the vicinity thereof occurs, electric field noise with the same frequency as the frequency of the common mode component is generated. do. If the radiated electric field noise interferes with the wireless communication unit 500, a communication failure may occur in the wireless communication unit 500. FIG.

In the first embodiment, the connection member 902 is arranged so as to partially overlap at least one signal line 212 of the plurality of signal lines 212 when viewed in the Z direction. As a result, as shown in FIG. 6A , connection member 902 secures a path for a return current flowing from flexible wiring board 200 to rigid wiring board 101 .

In the first embodiment, the connection member 902 overlaps a portion of at least one signal line 212 of the plurality of signal lines 212 in the X direction when viewed in the Z direction, and a portion of the at least one signal line 212 in the Y direction or overlap with the whole. In the example of FIG. 5(b), the connection member 902 partially connects two or more of the six signal lines 212, specifically five signal lines 212, when viewed in the Z direction. Overlap. More specifically, when viewed in the Z direction, the connection member 902 overlaps a portion of each of the five signal lines 212 in the X direction. In addition, when viewed in the Z direction, the connection member 902 overlaps the entire Y direction of each of the four signal lines 212 among the five signal lines 212 and overlaps a portion of the one signal line 212 in the Y direction.

As described above, according to the first embodiment, the connection member 902 secures the path of the return current flowing from the flexible wiring board 200 to the rigid wiring board 101 . Accordingly, it is possible to reduce the radiation noise from the connector 103 which is the connection portion between the flexible wiring board 200 and the rigid wiring board 101 and the signal line 212 in the vicinity thereof. Moreover, since radiation noise can be reduced, noise interference can be reduced in the wireless communication unit 500 shown in FIG.

It is preferable that the signal terminal 901 and the connection member 902 are close to each other without contact.

(Example 1)
Example 1 is an example in which the communication module 800 of the first embodiment is simulated by numerical calculation by a computer. In Example 1, a computer performed a three-dimensional electromagnetic field simulation. A three-dimensional electromagnetic field simulator HFSS manufactured by ANSYS was used for the computer simulation. A simulation model is explained. 7(a) to 7(c) are explanatory diagrams of the configuration used for the simulation of the first embodiment. FIG. 7A is a plan view schematically showing rigid wiring board 101, connector 103, and connection member 902. FIG. FIG. 7(b) is a plan view schematically showing flexible wiring board 200, connector 103, and connection member 902. FIG. FIG. 7(c) is a diagram schematically showing a cross section along line VIIC--VIIC shown in FIGS. 7(a) and 7(b).

The dimensions used in the simulation will be explained. Rigid wiring board 101 was a two-layer board with an outer shape of 5.3 mm wide, 10.35 mm long, and 0.236 mm thick. Rigid wiring board 301 (FIG. 2(b)) on the receiving side of signals transmitted from rigid wiring board 101 also has the same dimensions.

The flexible wiring board 200 was a two-layer substrate having an outer shape of 10.35 mm wide, 129 mm long, and 57.5 μm thick. The dimensions of the signal line 212 on the conductor layer 201 were 54 μm in width, 129 mm in length, and 6 μm in thickness.

As shown in FIG. 7A, a rigid wiring board 101 is provided with 20 signal lines 111 as a plurality of first signal lines. A digital signal transmitted through the signal line 111 is a differential signal. Therefore, a pair of adjacent signal lines 111 form a differential pair wiring through which differential signals are transmitted. In addition, a pair of signal lines 111 in each differential pair of wirings was short-circuited at the starting ends thereof, and a 1 W feeding point 7010 was provided at the short-circuited portion so that noise would propagate through the differential pair of wirings. In the rigid wiring board 101, there are ten pairs of signal lines 111, that is, differential pair wirings. Each signal line 111 was supplied with AC voltage and AC current with a frequency of 0.1 to 8.0 GHz at intervals of 0.1 GHz under the condition that the power was always 1 W.

Similarly, as shown in FIG. 7B, the flexible wiring board 200 is provided with 20 signal lines 212 as a plurality of second signal lines. A pair of adjacent signal lines 212 constitute a differential pair wiring through which differential signals are transmitted. In the flexible wiring board 200, there are ten pairs of signal lines 212, that is, differential pair wirings. The interval between the pair of signal lines 212 was set to 55 μm. In the flexible wiring board 200, the interval between two adjacent differential pair wirings was set to 141 μm.

Also, the width of each ground line 220 is set to 1.2 mm. The distance in the Y direction between the ground line 220 and the signal line 212 adjacent to the ground line 220 was set to 215 μm. The thickness of the shield member 210 in the Z direction was set to 5 μm. Each ground line 220 was arranged so as to overlap the shield member 210 when viewed in the Z direction, and was electrically connected to the shield member 210 at intervals of 5 mm in the X direction.

Connector 103 was provided on rigid wiring board 101 so that the distance in the Z direction between rigid wiring board 101 and flexible wiring board 200 was 95 μm. Then, the connection member 902 was provided at a position 0.2 mm away from the connector 103 in the +X direction so that the connection member 902 overlaps all the signal lines 212 in the Y direction when viewed in the Z direction. The dimensions of the connecting member 902 were 0.3 mm in length, 5.3 mm in width, and 0.95 mm in height.

The insulator 205 of the flexible wiring board 200 is made of polyimide having a dielectric constant of 3.5. The insulator 110 of the rigid wiring board 101 was made of FR4 with a dielectric constant of 4.3. The signal line 111, the ground line 120, the signal line 212, the ground line 220, the signal terminal 901 and the ground terminal 903 of the connector 103, and the connection member 902 were made of copper with a conductivity of 5.8×10 ⁷ S/m.

Twenty-two measurement points were set at positions 5 mm away from the shield member 210 in the -Z direction. Twenty-two measurement points were set at intervals of 2.5 mm from the center of flexible wiring board 200 toward rigid wiring board 301 (FIG. 2A) in the X direction. The electric field intensity of the electric field noise at each measurement point was obtained by simulation under each condition with and without the connection member 902 . Table 1 shows the maximum electric field strength among the 22 measurement points for each condition of the presence or absence of the connection member 902 . Each value of the electric field strength shown in Table 1 indicates a value at 5.5 GHz, which is the frequency of the wireless LAN, as an example.

From Table 1, it can be seen that the electric field intensity of the electric field noise is reduced by about 8.4 dBV/m when the connection member 902 is present, compared to when the connection member 902 is not provided. Accordingly, in the first embodiment, electric field noise, that is, radiation noise can be reduced.

Next, a simulation was performed by changing the width of the connection member 902 in the Y direction. Let Li be the length (width) of each signal line ₂₁₂ in the Y direction. i is a positive integer from 1 to n. n is the total number of signal lines 212; For example, if the number of signal lines 212 is 20, then n=20. Assuming that the total length (width) of the plurality of signal lines 212 in the Y direction is L _sum , the following formula (1) holds.

For example, if the length of each of the 20 signal lines 212 in the Y direction is the same length L, the total length L _sum is 20×L.

Among the plurality of signal lines 212, the length (width) in the Y direction of the portion of the signal line 212 that overlaps with the connection member 902 when viewed in the Z direction is _Wj . j is a positive integer from 1 to m. m is the number of signal lines 212 overlapping the connecting member 902 when viewed in the Z direction, and 1≦m≦n. Let W _sum be the sum of the Y-direction lengths of the portions of the plurality of signal lines 212 that overlap the connecting member 902 when viewed in the Z-direction, then the following equation (2) holds.

For example, when looking at one signal line 212 that overlaps the connection member 902 when viewed in the Z direction, the Y-direction length _Wj of the portion of the signal line 212 that overlaps the connection member 902 is the Y-direction length of the signal line 212. length (width) or less.

When the ratio of the total length W _sum to the total length L _sum is R, the following formula (3) holds.

FIG. 8 shows the result of simulating the electric field strength dBV/m of the electric field noise with respect to the ratio R. In FIG. 8 is a graph showing a simulation result of electric field intensity of electric field noise in Example 1. FIG. The horizontal axis is the ratio R, and the vertical axis is the electric field strength dBV/m of the electric field noise.

As a result of the simulation, it was found that the electric field intensity of the electric field noise decreased as the ratio R increased. It was found that the electric field strength of the electric field noise is almost saturated when the ratio R is 3/5 or more. Therefore, the ratio R is preferably 3/5 or more and 1 or less, which is highly effective in reducing electric field noise.

In the signal line 212 overlapping the connection member 902 when viewed in the Z direction, if the Y-direction length _Wj of the portion overlapping the connection member 902 is the same as the Y-direction length _Li of the signal line 212, The denominator and numerator in Equation (3) can also be represented by the number of signal lines. In this case, the signal line 212 that overlaps the connection member 902 when viewed in the Z direction partially overlaps the connection member 902 in the X direction and entirely overlaps the connection member 902 in the Y direction.

The total number of the plurality of signal lines 212 is n as described above, and the number of signal lines 212 partially overlapping the connection member 902 in the X direction when viewed in the Z direction among the plurality of signal lines 212 is m as described above. . In this case, the ratio R of the number m to the total number n is represented by m/n. Therefore, in this case as well, the ratio R is preferably 3/5 or more and 1 or less, which is highly effective in reducing electric field noise. For example, in the example of twenty signal lines 212, there would be ten differential pair wirings. In this example, it is preferable that 6 to 10 differential pair wirings out of the 10 differential pair wirings overlap the connection member 902 when viewed in the Z direction.

[Second embodiment]
A second embodiment will be described. Although the flexible wiring board 200 is detachable from the connector 103 in the first embodiment, the connection form between the flexible wiring board 200 and the rigid wiring board 101 is not limited to this. FIG. 9A is a plan view showing a portion of rigid wiring board 101 and a connection structure according to the second embodiment. FIG. 9(b) is a plan view showing a portion of a flexible wiring board 200A and a connection structure according to the second embodiment. FIG. 9C is a cross-sectional view of rigid wiring board 101, flexible wiring board 200A, and connection structure according to the second embodiment. FIG. 9(c) schematically shows a cross section along line IXC-IXC shown in FIGS. 9(a) and 9(b). In the second embodiment, the same reference numerals are used for the same configuration as in the first embodiment, and detailed description thereof is omitted.

A rigid wiring board 101 of the second embodiment has the same configuration as that of the first embodiment. 200 A of flexible wiring boards of 2nd Embodiment are flexible printed wiring boards, and are an example of a 2nd wiring board. The flexible wiring board 200A is the same as the first embodiment except that the shape of the end 231A differs from the shape of the end 231 of the first embodiment. 200 A of flexible wiring boards are two-layer flexible printed wiring boards which have the conductor layers 201 and 202 like 1st Embodiment. A flexible wiring board 200A has a plurality of signal lines 212 and a plurality of ground lines 220 arranged on a conductor layer 201, and a shield member 210 arranged on the conductor layer 202, as in the first embodiment.

In the second embodiment, the rigid wiring board 101 and the flexible wiring board 200A are directly connected by a conductive bonding material such as solder instead of the connector 103 shown in FIGS. Connection strength is ensured. Specifically, the plurality of signal lines 111 of the rigid wiring board 101 and the plurality of signal lines 212 of the flexible wiring board 200A are electrically and mechanically connected at a plurality of signal joints 901A. Each signal junction 901A is an example of a first connection member. Ground line 120 of rigid wiring board 101 and multiple ground lines 220 of flexible wiring board 200A are electrically and mechanically connected at multiple ground joints 903A. Each ground joint portion 903A is an example of a ground connection member and an example of a second connection member. Each signal joint 901A and each ground joint 903A is made of a conductive joint material such as solder.

As described above, according to the second embodiment, the connection member 902 secures the path of the return current flowing from the flexible wiring board 200A to the rigid wiring board 101 . Accordingly, it is possible to reduce radiation noise from the signal joint portion 901A, which is the connection portion between the flexible wiring board 200A and the rigid wiring board 101, and the signal line 212 in the vicinity thereof. Moreover, since radiation noise can be reduced, noise interference can be reduced in the wireless communication unit 500 shown in FIG.

The ground line 120 and the connection member 902 may be connected with a conductive double-sided adhesive tape, or may be connected with a conductive bonding material such as solder. Similarly, the shield member 210 and the connection member 902 may be connected with a conductive double-sided adhesive tape, or may be connected with a conductive bonding material such as solder. Also, the connection member 902 itself may be a conductive double-sided adhesive tape, or may be a conductive bonding material such as solder.

[Third embodiment]
A third embodiment will be described. FIG. 10(a) is a plan view showing part of a rigid wiring board 101 and a connection structure according to the third embodiment. FIG. 10(b) is a plan view showing a portion of a flexible wiring board 200A and a connection structure according to the third embodiment. 10(c) and 10(d) are cross-sectional views of a rigid wiring board 101, a flexible wiring board 200A, and a connection structure according to the third embodiment. FIG. 10(c) schematically shows a cross section along line XC-XC shown in FIGS. 10(a) and 10(b). FIG. 10(d) schematically shows a cross section along line XD-XD shown in FIGS. 10(a) and 10(b). In the third embodiment, the same reference numerals are used for the same configurations as in the first and second embodiments, and detailed description thereof is omitted.

A rigid wiring board 101 of the third embodiment has the same configuration as those of the first and second embodiments. 200 A of flexible wiring boards of 3rd Embodiment are the same as that of 2nd Embodiment. In the third embodiment, the configuration of a connection member 902B, which is an example of a conductive member, differs from the connection members 902 of the first and second embodiments. The connection structure between the signal line 111 of the rigid wiring board 101 and the signal line 212 of the flexible wiring board 200A and the connection structure between the ground line 120 of the rigid wiring board 101 and the ground line 220 of the flexible wiring board 200A are second. It is similar to the embodiment. Specifically, the plurality of signal lines 111 of the rigid wiring board 101 and the plurality of signal lines 212 of the flexible wiring board 200A are electrically and mechanically connected at a plurality of signal joints 901A. Ground line 120 of rigid wiring board 101 and multiple ground lines 220 of flexible wiring board 200A are electrically and mechanically connected at multiple ground joints 903A. Each signal joint 901A and each ground joint 903A is made of a conductive joint material such as solder.

The connection member 902B is formed in a substantially U shape when viewed in the Z direction. The connection member 902B is arranged so as to contact each ground joint 903A. This further increases the connection strength between rigid wiring board 101 and flexible wiring board 200A.

As described above, according to the third embodiment, the connecting member 902B secures the path of the return current flowing from the flexible wiring board 200A to the rigid wiring board 101. FIG. Accordingly, it is possible to reduce radiation noise from the signal joint portion 901A, which is the connection portion between the flexible wiring board 200A and the rigid wiring board 101, and the signal line 212 in the vicinity thereof. Moreover, since radiation noise can be reduced, noise interference can be reduced in the wireless communication unit 500 shown in FIG.

[Fourth embodiment]
A fourth embodiment will be described. In the first to third embodiments, the case where at least one conductive member is one connection member 902 or 902B has been described, but the present invention is not limited to this. Depending on the wiring structure of the first wiring board and the second wiring board, it may be preferable for the at least one conductive member to include a plurality of conductive members. FIG. 11(a) is a plan view showing a portion of a rigid wiring board 101C and a connection structure according to the fourth embodiment. FIG. 11(b) is a plan view showing a portion of a flexible wiring board 200C and a connection structure according to the fourth embodiment. FIG. 11(c) is a cross-sectional view of a rigid wiring board 101C, a flexible wiring board 200C, and a connection structure according to the fourth embodiment. FIG. 11(c) schematically shows a cross section along the XIC-XIC line shown in FIGS. 11(a) and 11(b). In the fourth embodiment, the same reference numerals are used for the same configurations as in the first to third embodiments, and detailed description thereof is omitted.

In the fourth embodiment, in the communication module, the rigid wiring board 101 and the flexible wiring board 200 shown in FIG. 2B are replaced with the rigid wiring board 101C and the flexible wiring board 200C shown in FIGS. is replaced with 101 C of rigid wiring boards of 4th Embodiment are an example of a 1st wiring board, and are rigid printed wiring boards. 200 C of flexible wiring boards of 4th Embodiment are an example of a 2nd wiring board, and are flexible printed wiring boards. Rigid wiring board 101C and flexible wiring board 200C are connected by connector 103C. A differential signal, which is a digital signal, is transmitted to the flexible wiring board 200C from the image sensor 102 mounted on the rigid wiring board 101C.

Rigid wiring board 101C has a plurality of signal lines 111C wired on both sides of connector 103C. Each signal line 111C is an example of a first signal line. FIG. 11A shows a total of 12 signal lines 111C as the plurality of signal lines 111C. 12 signal lines 111C constitute 6 differential pair wirings. The twelve signal lines 111C are composed of six signal lines 111C wired on one side of the connector 103C and six signal lines 111C wired on the other side opposite to the one side of the connector 103C.

A rigid wiring board 101C of the fourth embodiment differs from the rigid wiring board 101 of the first embodiment in the number of signal lines 111C and the wiring structure, but the rest of the configuration is the same as that of the rigid wiring board 101 of the first embodiment. is almost the same as Rigid wiring board 101C has at least two conductor layers 1011C and 1012C. 1011 C of conductor layers and 1012 C of conductor layers are arrange|positioned facing the Z direction through the insulator 110C which is an insulating substrate. Each signal line 111C is wired across the two conductor layers 1011C and 1012C. The ground line 120C is an example of a first ground line and is wired on the conductor layer 1011C.

The flexible wiring board 200C includes a plurality of signal lines 212C wired on both sides of the connector 103C, a plurality of ground lines 220C wired on both sides of the connector 103C, and a shield member arranged to avoid the connector 103C. 210C and Each ground line 220C is an example of a second ground line. FIG. 11B shows a total of 12 signal lines 212C as the plurality of signal lines 212C. 12 signal lines 212C constitute 6 sets of differential pair wiring. The twelve signal lines 212C are composed of six signal lines 212C wired on one side of the connector 103C and six signal lines 212C wired on the other side opposite to the one side of the connector 103C.

Although the flexible wiring board 200C of the fourth embodiment differs from the flexible wiring board 200 of the first embodiment in the number of signal lines 212C and the wiring structure, other configurations are the same as those of the flexible wiring board 200 of the first embodiment. is almost the same as A flexible wiring board 200C is a two-layer flexible printed wiring board having conductor layers 201C and 202C arranged opposite to each other in the Z direction via an insulator 205C, as in the first embodiment. The conductor layer 201C is an example of a first layer, and the conductor layer 202C is an example of a second layer different from the first layer. Each signal line 212C and ground line 220C are arranged on the conductor layer 201C, and the shield member 210C is arranged on the conductor layer 202C.

The connector 103C has a plurality of signal terminals 901C electrically connecting the plurality of signal lines 111C and the plurality of signal lines 212C. Each signal terminal 901C is an example of a first connection member. Also, the connector 103C has a plurality of ground terminals 903C electrically connecting the ground line 120C and the plurality of ground lines 220C. Each ground terminal 903C is an example of a ground connection member and an example of a second connection member.

In the fourth embodiment, two connection members 902C are provided between the rigid wiring board 101C and the flexible wiring board 200C for the twelve signal lines 212C. Each of the two connecting members 902C is an example of a conductive member. The material of each connecting member 902C is a conductive material, that is, a metal. Each connection member 902C electrically connects the shield member 210C of the flexible wiring board 200C and the ground line 120C of the rigid wiring board 101C. The connection member 902C is connected to a portion 1201C of the ground line 120C exposed through an opening formed in the solder resist 105C of the rigid wiring board 101C.

One of the two connection members 902C is arranged corresponding to six signal lines 212C wired on one side of the connector 103C. The other of the two connection members 902C is arranged corresponding to the six signal lines 212C wired on the other side with respect to the connector 103C. Each connection member 902C is arranged so as to partially overlap at least one signal line 212C among the six signal lines 212C when viewed in the Z direction.

Each of the plurality of signal lines 111C includes a conductor pattern 1111C, which is an example of a first conductor pattern arranged on the conductor layer 1011C, and a conductor pattern 1112C, which is an example of a second conductor pattern arranged on the conductor layer 1012C. . Also, each of the plurality of signal lines 111C includes a via conductor 1113C that electrically connects the conductor pattern 1111C and the conductor pattern 1112C. Each conductor pattern 1111C is in contact with each signal terminal 901C. With the above configuration, each signal line 111C is wired so as not to interfere with the ground line 120C arranged on the conductor layer 1012C.

As described above, according to the fourth embodiment, the path of the return current flowing from the flexible wiring board 200C to the rigid wiring board 101C is secured by the plurality of connection members 902C. As a result, it is possible to reduce radiation noise from the connector 103C, which is the connecting portion between the flexible wiring board 200C and the rigid wiring board 101C, and the signal line 212C in the vicinity thereof. Moreover, since radiation noise can be reduced, noise interference can be reduced in the wireless communication unit 500 shown in FIG.

[Modified example of the fourth embodiment]
FIGS. 12(a) to 12(c) are diagrams showing modifications of the fourth embodiment. FIG. 12(a) is a plan view showing a portion of a rigid wiring board 101C of a modification and a connection structure. FIG. 12(b) is a plan view showing a part of a flexible wiring board 200C of a modified example and a connection structure. FIG. 12(c) is a cross-sectional view of a rigid wiring board 101C, a flexible wiring board 200C, and a connection structure of a modification. FIG. 12(c) schematically shows a cross section along line XIIC-XIIC shown in FIGS. 12(a) and 12(b). In the modified example, the same reference numerals are used for the same configuration as in the fourth embodiment, and detailed description thereof is omitted. In the fourth embodiment, the case where the plurality of conductive members are two connecting members 902C has been described, but the present invention is not limited to this. The plurality of conductive members may be three or more connecting members 902C. At that time, each connecting member 902C is preferably arranged so as to be close to the connector 103C.

[Fifth embodiment]
A fifth embodiment will be described. In the first embodiment, the connection member 902 electrically connects the ground line 120 of the rigid wiring board 101 and the shield member 210 of the flexible wiring board 200. It is not limited. FIG. 13(a) is a plan view showing a portion of rigid wiring board 101 and a connection structure according to the fifth embodiment. FIG. 13(b) is a plan view showing a portion of the flexible wiring board 200 and the connection structure according to the fifth embodiment. FIG. 13(c) is a cross-sectional view of rigid wiring board 101, flexible wiring board 200, and connection structure according to the fifth embodiment. FIG. 13(c) schematically shows a cross section along line XIII-XIII shown in FIGS. 13(a) and 13(b). In the fifth embodiment, the same reference numerals are used for the same configurations as in the first embodiment, and detailed description thereof is omitted.

A rigid wiring board 101 of the fifth embodiment is a rigid printed wiring board and has the same configuration as that of the first embodiment. A flexible wiring board 200 of the fifth embodiment is a flexible printed wiring board and has the same configuration as that of the first embodiment. Between rigid wiring board 101 and flexible wiring board 200, connection member 902D, which is an example of a conductive member, is arranged. The material of the connection member 902D is a material having conductivity, that is, a metal.

In the fifth embodiment, connection member 902</b>D contacts shield member 210 of flexible wiring board 200 but does not contact ground line 120 of rigid wiring board 101 . An insulating member 1310 is provided between the connecting member 902</b>D and the ground line 120 of the rigid wiring board 101 . The path of the return current flowing from flexible wiring board 200 to rigid wiring board 101 in such a configuration is substantially the same as in the first embodiment because of capacitive coupling between connection member 902D and ground line 120. FIG.

The insulating member 1310 is, for example, polyimide tape. The material of the insulating member 1310 is not particularly limited as long as it is electrically insulating. It is preferable that the thickness of the insulating member 1310 in the Z direction is a thickness that facilitates capacitive coupling between the connection member 902D and the ground line 120 . Specifically, it is preferably 0.2 mm or less. More preferably, it is 0.1 mm or less.

As described above, according to the fifth embodiment, the path of the return current flowing from flexible wiring board 200 to rigid wiring board 101 is secured by connecting member 902</b>D and insulating member 1310 . Accordingly, it is possible to reduce radiation noise from the signal terminal 901 which is the connection portion between the flexible wiring board 200 and the rigid wiring board 101 and the signal line 212 in the vicinity thereof. Moreover, since radiation noise can be reduced, noise interference can be reduced in the wireless communication unit 500 shown in FIG.

Insulating member 1310 may be provided between connecting member 902D and shield member 210 of flexible wiring board 200 instead of between connecting member 902D and ground line 120 . Also, two insulating members 1310 may be provided between the connecting member 902D and the ground line 120 and between the connecting member 902D and the shield member 210. FIG.

(Example 2)
In Example 2, based on the simulation performed in Example 1, the noise interference amount of the wireless communication unit 500 mounted in the digital camera, which is the imaging device 1000, was measured. 14, 15(a) and 15(b) are schematic diagrams showing a measurement system for measuring reception sensitivity in the second embodiment. The reception sensitivity was measured by calculating the ratio of the number of packets transmitted from the evaluation device and the number of packets received by the wireless communication unit 500 using a transmission/reception characteristic measuring instrument 1401 (manufactured by Anritsu MT8862A).

FIG. 14 shows a wireless communication unit 500, a rigid wiring board 101, a flexible wiring board 200, and a transmission/reception characteristics measuring device 1401, which are part of the imaging device 1000. FIG. Flexible wiring board 200 has one end connected to rigid wiring board 101 and the other end connected to rigid wiring board 1400 . Wireless communication unit 500 was brought close to flexible wiring board 200, and the reception sensitivity of noise that interfered with wireless communication unit 500 among noises radiated from flexible wiring board 200 was measured.

The measurement conditions will be explained in more detail. 15(a) is a side view showing part of the electronic module 1501 in Example 2, and FIG. 15(b) is a plan view showing part of the electronic module 1501 in Example 2. FIG. As shown in FIGS. 15A and 15B, the flexible wiring board 200 was stretched straight in the X direction. Rigid wiring board 101 and rigid wiring board 1400 were fixed to one surface of metal frame 1502 via metal member 1503 .

Rigid wiring board 101 has external dimensions of 129.0 mm in X direction, 210.0 mm in Y direction, and 1.6 mm in thickness in Z direction. Rigid wiring board 101 is a six-layer board. Twenty ICs (THCV215 manufactured by Thine) for outputting differential signals were mounted on rigid wiring board 101 . Flexible wiring board 200 has external dimensions of 144.0 mm in X direction, 27.0 mm in Y direction, and 37.5 μm in thickness in Z direction. The flexible wiring board 200 is a single-layer substrate on which signal lines are arranged. A shield member 210 made of silver was provided on the entire surface of one side of the flexible wiring board 200 by shield printing. DF40C-70DS-0.4V [51] and DF40C-70DP-0.4V [51] manufactured by Hirose Electric Co., Ltd. were used as connectors 1504 for connecting flexible wiring board 200 and rigid wiring board 101 .

E02S020015RT-450 manufactured by Seiwa Denki Co., Ltd. was used for the connection member 902 that connects the shield member 210 and the rigid wiring board 101 . Ground lines were arranged at both ends and the center of the flexible wiring board 200 in the Y direction, which is the width direction.

Rigid wiring board 1400 has external dimensions of 50.0 mm in X direction, 70.0 mm in Y direction, and 1.6 mm in thickness in Z direction. Rigid wiring board 1400 is a six-layer board.

DF40C-70DS-0.4V [51] and DF40C-70DP-0.4V [51] manufactured by Hirose Electric Co., Ltd. were used for the connector 1505 connecting the flexible wiring board 200 and the rigid wiring board 1400 .

Two signal lines included in the differential pair wiring provided on rigid wiring board 1400 were terminated with a resistance of 100Ω. Rigid wiring boards 101 and 1400 were electrically connected to metal frame 1502 with metal member 1503 having a height of 15.0 mm and a diameter of 6 mm. The metal frame 1502 was a metal plate with a length in the X direction of 325 mm, a length in the Y direction of 250 mm, and a thickness in the Z direction of 1.0 mm. In order to measure electromagnetic noise radiated from flexible wiring board 200 , wireless communication unit 500 was installed at a point 5 mm high from the center of flexible wiring board 200 .

The frequency of the differential signal was set to 2.65 GHz. The rigid wiring board 101 was provided with 20 sets of differential pair wirings composed of two signal lines. When a differential signal was output to flexible wiring board 200, electromagnetic noise due to common mode current was detected over a frequency band from 1 GHz to 6 GHz.

FIG. 16 is a schematic diagram showing a cross-sectional structure of a flexible wiring board 200 of Example 2. As shown in FIG. Signal line 1600 is made of copper. The insulating member 1601 is made of polyimide. The wiring width L of each signal line 1600 is 55 μm, the distance S between two signal lines 1600 of the differential pair wiring is 140 μm, the thickness T1 of each signal line 1600 is 6 μm, and the thickness T2 of the insulating member 1601 is 37.5 μm. and Also, the thickness T3 of the shield member 210 was set to 5 μm, and the distance D between the shield member 210 and the metal frame 1502 was set to 15.0 mm. The dielectric constant of polyimide was 3.38.

Radiation noise was measured under four conditions. 17(a) to 18(b) are schematic diagrams showing conditions during measurement in Example 2. FIG. Structure A is a condition in which there is no connection member 902 . Structure B is a condition in which the connection member 902 is not in contact with the ground line 120 and the shield member 210 . Structure C is a condition in which the connection member 902 is in contact with the ground line 120 but not in contact with the shield member 210 . Structure D is a condition in which the connection member 902 is in contact with the shield member 210 but not in contact with the ground line 120 . Structure E is the case where the connection member 902 is in contact with the ground line 120 and the shield member 210 . In structure B, structure C, and structure D, a polyimide tape with a thickness of 0.1 mm was used as the insulating member 1310 . The amount of noise interference for Structures A to E was obtained. The results are shown in FIG. FIG. 19 is a graph showing the amount of electromagnetic noise interference at 5.3 GHz, which is the frequency of wireless LAN. The amount of interference is the difference obtained by subtracting the reception sensitivity deteriorated due to noise interference from the reception sensitivity in the absence of noise.

From FIG. 19, it was found that Structures B to E had less noise interference than Structure A, which is a comparative example. In particular, it was found that Structure E has the highest effect of reducing the amount of noise interference. Moreover, it was found that the structure C and the structure D were able to fully exhibit the effect of reducing the amount of noise interference with respect to the structure A and the structure B.

The present invention is not limited to the embodiments described above, and many modifications are possible within the technical concept of the present invention. Moreover, the effects described in the embodiments are merely enumerations of the most suitable effects resulting from the present invention, and the effects of the present invention are not limited to those described in the embodiments.

As described in the first to fifth embodiments, it is preferable to provide the conductive member on the first wiring board on the transmission side of the digital signal, but the present invention is not limited to this. A conductive member may be provided on the first wiring board on the receiving side of the digital signal. For example, in the example of the first embodiment, a connection member 902, which is an example of a conductive member, may be provided between rigid wiring board 301 and flexible wiring board 200. FIG. Moreover, the conductive member may be provided on both the first wiring board on the digital signal transmission side and the first wiring board on the digital signal reception side.

Further, in the first to fifth embodiments, the case where the electronic component that transmits the digital signal is the image sensor 102 has been described. That is, since the image sensor 102 transmits a large amount of image data, the number of signal lines 111 is large. Therefore, from the viewpoint of securing a return current path, it is preferable to arrange a conductive member between the rigid wiring board on which the image sensor 102 is mounted and the flexible wiring board, but the present invention is not limited to this. . A conductive member may be provided between the first wiring board on which electronic components other than the image sensor 102 are mounted and the second wiring board.

Further, although the number of signal lines 111 is six in the first to fifth embodiments, the number of signal lines 111 is not limited to this. The present invention is applicable even if the number of signal lines increases, and in particular the number of signal lines may be 20 or more.

Also, in the first to fifth embodiments, the case where the electronic device is the imaging device 1000 has been described, but the electronic device is not limited to this. The present invention can also be applied to electronic devices other than imaging devices. In that case, the electronic device preferably has a wireless communication unit capable of wirelessly communicating with the external device.

DESCRIPTION OF SYMBOLS 101... Rigid wiring board (1st wiring board), 111... Signal line (1st signal line), 120... Ground line (1st ground line), 200... Flexible wiring board (2nd wiring board), 201... Conductor layer (First layer) 202 Conductor layer (second layer) 210 Shield member 212 Signal line (second signal line) 800 Communication module 901 Signal terminal (first connection member) 902 Connection member (conductive member), 1310... Insulating member

Claims (20)

a first wiring board having a plurality of first signal lines and a first ground line;
a second wiring board having a first layer including a plurality of second signal lines and a second layer including a shield member;
a plurality of first connection members electrically connecting the plurality of first signal lines and the plurality of second signal lines, respectively;
at least one conductive member provided between the first ground line and the shield member;
The at least one conductive member is arranged to partially overlap at least one second signal line among the plurality of second signal lines when viewed in a direction perpendicular to the main surface of the first wiring board. ing,
A communication module characterized by: the at least one conductive member is electrically connected to at least one of the first ground line and the shield member;
The communication module according to claim 1, characterized by: the at least one conductive member is electrically connected to the first ground line and the shield member;
The communication module according to claim 1, characterized by: The first layer and the second layer are arranged with an insulator interposed therebetween,
4. The communication module according to any one of claims 1 to 3, characterized in that: The at least one second signal line includes 20 or more second signal lines,
5. The communication module according to any one of claims 1 to 4, characterized in that: The plurality of second signal lines are arranged at intervals in a predetermined direction,
the conductivity of the at least one of the plurality of second signal lines with respect to the total length of the plurality of second signal lines in the predetermined direction when viewed in a direction perpendicular to the main surface of the first wiring board; The ratio of the total length of the portion overlapping with the member is 3/5 or more and 1 or less,
6. The communication module according to any one of claims 1 to 5, characterized in that: The plurality of second signal lines are arranged at intervals in a predetermined direction,
A second wiring board that partially overlaps the at least one conductive member among the plurality of second signal lines with respect to the total number of the plurality of second signal lines when viewed in a direction perpendicular to the main surface of the first wiring board. The ratio of the number of signal lines is 3/5 or more and 1 or less.
6. The communication module according to any one of claims 1 to 5, characterized in that: the first layer of the second wiring board includes a second ground line;
further comprising a second connection member that electrically connects the first ground line of the first wiring board and the second ground line of the second wiring board;
The communication module according to any one of claims 1 to 7, characterized in that: the at least one conductive member is arranged in contact with the second connection member;
9. The communication module according to claim 8, characterized by: the at least one electrically conductive member comprises a plurality of electrically conductive members;
A communication module according to any one of claims 1 to 9, characterized in that: The first wiring board is a rigid wiring board,
The second wiring board is a flexible wiring board,
A communication module according to any one of claims 1 to 10, characterized in that: The second wiring board is detachably connected to the first wiring board via the plurality of first connection members,
A communication module according to any one of claims 1 to 11, characterized in that: The plurality of first signal lines are respectively joined to the plurality of second signal lines by the plurality of first connection members,
A communication module according to any one of claims 1 to 11, characterized in that: each of the plurality of first signal lines includes a first conductor pattern with which a corresponding first connection member of the plurality of first connection members contacts;
14. A communication module according to any one of claims 1 to 13, characterized in that: each of the plurality of first signal lines includes a second conductor pattern electrically connected to the first conductor pattern by a via conductor;
15. A communication module according to claim 14, characterized in that: further comprising an electronic component mounted on the first wiring board and electrically connected to the plurality of first signal lines;
16. A communication module according to any one of claims 1 to 15, characterized in that: The electronic component is configured to transmit a signal to each of the plurality of first signal lines,
17. A communication module according to claim 16, characterized in that: The electronic component is configured to transmit a differential signal as the signal to two first signal lines among the plurality of first signal lines,
18. A communication module according to claim 17, characterized in that: a housing;
a wireless communication unit arranged inside the housing and capable of wireless communication with an external device;
a communication module according to any one of claims 1 to 18 arranged inside the housing,
An electronic device characterized by: a housing;
a wireless communication unit arranged inside the housing and capable of wireless communication with an external device;
a communication module according to any one of claims 16 to 18 arranged inside the housing,
the electronic component of the communication module is an image sensor;
An electronic device characterized by:

Images