Electronic Board

Abstract

An electronic substrate provided with: a substrate having an upper surface ground on an upper surface thereof; at least one first land formed on the upper surface and connected to a first signal line; at least one second land formed on the upper surface and connected to a second signal line; at least one third land disposed on the upper surface between the first land and the second land, and connected to the upper surface ground; and at least one fourth land disposed on the upper surface opposite the third land with the first land therebetween, and connected to the upper surface ground.

Description

[Technical field]

[0001] The present invention relates to an electronic substrate. [Background technology]

[0002] Patent Document 1 discloses a camera including a circuit board that converts light passing through a lens into an electric signal, a connector having an outer conductor and connecting the circuit board to an external cable, a shielding conductor arranged on the outside of the circuit board, and an insulating housing that accommodates the circuit board and the shielding conductor. The connector in this camera is composed of an inner connector mounted on the circuit board, an intermediate connector connected to the inner connector and connected to the shielding conductor, and an outer connector that connects an external cable to the intermediate connector, the shielding conductor is supported by the outer conductor of the intermediate connector, the support structure of the shielding conductor by the outer conductor has rotational symmetry with respect to the entire circumference of the outer conductor, the shielding conductor has a form that envelops the circuit board starting from the boundary between the outer conductor and the shielding conductor of the intermediate connector, and the insulating housing is connected to and supported by the intermediate connector. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-75715 A Summary of the Invention

[0004] The present disclosure has been devised in view of the above-mentioned conventional situation, and has an object to provide an electronic board capable of suppressing the influence of noise.

[0005] The present disclosure relates to a substrate having a top surface ground, at least one first land formed on the top surface and connected to a first signal line, at least one second land formed on the top surface and connected to a second signal line, at least one third land disposed on the top surface between the at least one first land and the at least one second land and connected to the top surface ground, and at least one fourth land disposed on the top surface on the opposite side of the at least one first land from the at least one third land and connected to the top surface ground, At least one The first land and the first of further comprising a shielding conductor for electromagnetically shielding the signal line; The shield conductor has a first contact, The above At least one The third land To connection Be , The shield conductor is connected to a second contact The above At least one Connect to the 4th land and the at least one third land and the at least one fourth land are arranged so that a first magnetic field loop generated around the first contact point and a second magnetic field loop generated around the second contact point and rotating in the same direction as the first magnetic field loop cancel each other out. The present invention provides an electronic substrate.

[0006] According to the present disclosure, the effects of noise can be suppressed. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a diagram showing an example of a system configuration in which a camera having an electronic board according to a first embodiment is used; [Diagram 2] FIG. 1 is a plan view of an example of an electronic substrate according to a first embodiment; [Diagram 3] Schematic diagram showing the cross section of FIG. 2 [Figure 4A] FIG. 11 is a plan view showing an example of a magnetic field loop generation state in an electronic substrate according to a comparative example; [Figure 4B] Schematic diagram showing a cross section of FIG. 4A along line 4B-4B. [Diagram 5] FIG. 1 is a plan view illustrating an example of a magnetic field loop generation state in an electronic substrate according to the first embodiment; [Figure 6] An explanatory diagram showing an example of the correlation between the distance and the magnetic field attenuation caused by each of the two magnetic field loops. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] (Background to the content of the first embodiment) Patent Document 1 discloses a camera in which the shielding conductor has a shape that envelops the circuit board, and the support structure of the shielding conductor by the outer conductor of the intermediate connector has rotational symmetry with respect to the entire circumference of the outer conductor. As a result, the conventional camera stabilizes the potential, effectively shields electromagnetic waves radiated from peripheral devices toward the circuit board, and obtains noise resistance. The conventional camera also effectively shields electromagnetic waves radiated from the circuit board toward peripheral devices. However, in the structure of the circuit board of the conventional camera, when multiple cables connected to different systems are connected to the circuit board in close proximity to each other, interference occurs between the cables, and it may be impossible to suppress the effects of noise.

[0009] In the following first embodiment, an example of an electronic board capable of suppressing the influence of noise when multiple cables are used will be described.

[0010] Hereinafter, with reference to the drawings as appropriate, an embodiment specifically disclosing the configuration and operation of the camera board according to the present disclosure will be described in detail. However, more detailed explanation than necessary may be omitted. For example, detailed explanation of already well-known matters or duplicate explanation of substantially the same configuration may be omitted. This is to avoid the following explanation becoming unnecessarily redundant and to facilitate understanding by those skilled in the art. Note that the attached drawings and the following explanation are provided to enable those skilled in the art to fully understand the present disclosure, and are not intended to limit the subject matter described in the claims.

[0011] FIG. 1 is a diagram showing an example of the configuration of a system in which a camera 11 having an electronic board 13 according to the first embodiment is used. FIG. 2 is a plan view of the electronic board 13. The camera 11 according to the first embodiment is, for example, a vehicle-mounted camera. The electronic board 13 according to the first embodiment is described as an electronic board provided in the camera 11, but it goes without saying that the application is not limited to a camera. The electronic board 13 does not have to be a board provided in the camera 11. For example, the electronic board 13 may be a board provided in a converter for separating video, audio, control signals, and the like.

[0012] The camera 11 is configured to have at least a lens (not shown) and an image sensor (not shown). The image sensor is, for example, a solid-state imaging element such as a CCD (Charged-Coupled Device) or a CMOS (Complementary Metal Oxide Semiconductor), and converts an optical image formed on an imaging surface into an electric signal. The camera 11 is used, for example, as one of sensing technologies for realizing automatic driving of a vehicle, and is connected to the first control device 15 and the second control device 17 so as to be able to communicate with each other. The camera 11 transmits a video signal including a captured image to the first control device 15. The camera 11 also generates a control signal and transmits the generated control signal to the second control device 17. Note that, for example, the video signal is a signal (high-speed signal) having a frequency of several MHz or more, and the control signal is a signal (low-speed signal) having a frequency of several hundred kHz or less, and the video signal is a signal faster than the control signal.

[0013] The transmission method for the video signal including the image captured by the camera 11 may be an analog video signal output method or a high-speed serial digital signal output method capable of stably outputting high-definition image information.

[0014] The first control device 15 receives a video signal of an image captured by the camera 11, and controls the output of this video signal. The first control device 15 is, for example, an in-vehicle navigation system.

[0015] The second control device 17 executes control based on the control signal received from the camera 11. The second control device 17 is, for example, a central control device of the vehicle.

[0016] The electronic board 13 according to the first embodiment (see FIG. 2) is provided in the vehicle-mounted camera 11, and transmits a video signal to the first control device 15 and a control signal to the second control device 17.

[0017] The electronic board 13 includes a substrate 19 , a first land 21 , a second land 23 , a third land 25 , and a fourth land 27 .

[0018] The electronic board 13 is integrally connected to the camera 11. The electronic board 13 receives an electrical signal converted from, for example, an image sensor on the opposite side to a camera lens (not shown) (that is, the rear side of the camera 11).

[0019] The image sensor (not shown) is provided with a plurality of terminals (not shown) such as bumps on the side opposite to the imaging surface. The electronic board 13 is provided with a plurality of terminals for connecting between the camera 11 and a plurality of cables (not shown). Furthermore, each of the plurality of terminals is connected to each of the plurality of cables using solder or the like.

[0020] The electronic substrate 13 is a multi-layer substrate. Note that the electronic substrate 13 is not limited to a multi-layer substrate, and may be any of a single-sided substrate, a double-sided substrate, a build-up substrate, a rigid substrate, and a flexible substrate.

[0021] In electronic board 13, a plurality of first lands 21, a second land 23, a third land 25, and a fourth land 27 are formed on an upper surface 29 of substrate 19. In the first embodiment, the surface opposite to the lens (not shown) of camera 11 on which each of the plurality of lands is formed is referred to as upper surface 29 of substrate 19.

[0022] A ground 31 is formed on an upper surface 29 of the substrate 19. Each of the multiple lands formed on the upper surface 29 of the substrate 19 is connected to a terminal portion of an image sensor (not shown) or the like by a through hole, a via hole, or a printed circuit pattern. When the substrate 19 is a rigid substrate, for example, a glass epoxy substrate or the like can be used, but is not limited to this.

[0023] Furthermore, the substrate 19 is formed in a rectangular shape, but is not limited to this. For example, the substrate 19 may be formed in a rectangular shape with four rounded corners.

[0024] The ground 31 is made of copper foil or the like and has a shape similar to and smaller than the substrate 19, covering the upper surface 29. The ground 31 may be provided linearly, for example, along the shape of each of the multiple lands.

[0025] Each of the multiple first lands 21 is formed on the upper surface 29 of the substrate 19. Each of the multiple first lands 21 is arranged in a line along the long side of the substrate 19 and is formed insulated from the ground 31. The first land 21 is formed, for example, in a rectangular shape with the long side extending along the short side of the substrate 19. Note that the shape of each of the multiple first lands 21 is not limited to this. Furthermore, the number of each of the multiple first lands 21 is not limited to the number shown in FIG. 2, and may be one or three or more.

[0026] The second land 23 is formed on the upper surface 29 of the substrate 19. The second land 23 is arranged next to the left first land 21 among the multiple first lands 21 in the direction along the long side of the substrate 19, and is formed insulated from the ground 31. The second land 23 is formed in a rectangular shape with the long side extending along the short side of the substrate 19. Note that the shape of the second land 23 is not limited to this. Furthermore, the number of second lands 23 is not limited to the number shown in FIG. 2, and may be more than one.

[0027] The third land 25 is formed on the upper surface 29 of the substrate 19. The third land 25 is disposed between each of the multiple first lands 21 and the second land 23, and is formed so as to be connected to the ground 31. The third land 25 according to the first embodiment is formed in a substantially cross shape by cutting out the four corners of a rectangular shape into an L shape, so that the midpoints of the four sides are connected to the ground 31. As a result, the third land 25 can suppress the diffusion of heat due to thermal conduction and facilitate soldering when joining a wiring conductor using solder or the like.

[0028] The fourth land 27 is formed on the upper surface 29 of the substrate 19. The fourth land 27 is disposed on the opposite side of the third land 25 across each of the multiple first lands 21, and is formed by being connected to the ground 31. Like the third land 25, the fourth land 27 is formed in a substantially cross shape with the midpoints of the four sides connected to the ground 31 by cutting out the four corners of a rectangle in an L shape. This makes it possible for the fourth land 27 to easily perform soldering by suppressing the diffusion of heat due to thermal conduction when joining a wiring conductor using solder or the like.

[0029] In the electronic board 13, the multiple first lands 21, the second land 23, the third land 25, and the fourth land 27 are arranged in a line on the upper surface 29 of the board 19. These multiple lands are arranged in the order of the second land 23, the third land 25, the multiple first lands 21, and the fourth land 27 from one end side (the left end side in FIG. 2) of the board 19 shown in FIG. 2 to the other end side (the right end side in FIG. 2). The multiple first lands 21 are provided adjacent to each other for differential use. Therefore, in the electronic board 13, five lands consisting of the second land 23, the third land 25, the multiple first lands 21, and the fourth land 27 are arranged in an aligned manner along the long side of the board 19. The number and area of ​​each land are not limited to the example shown in FIG. 2.

[0030] In addition, in order to obtain the effect of reducing the influence of noise, the electronic board 13 according to the first embodiment is preferably configured such that the number of the third lands 25 and the number of the fourth lands 27 are the same and the third lands 25 and the fourth lands 27 are arranged symmetrically to each other, but is not limited thereto. For example, the number and area of ​​the third lands 25 and the fourth lands 27 may be different. Specifically, the area of ​​the third land 25 may be smaller or larger than the area of ​​the fourth land 27. Also, the third lands 25 and the fourth lands 27 may be plural. Specifically, two third lands 25 may be formed and one fourth land 27 may be formed. In such a case, the third lands 25 and the fourth land 27 are arranged side by side in a direction intersecting (preferably perpendicular to) a line passing through one third land 25 and one fourth land 27 (i.e., the 3-3 cross-sectional line in FIG. 2). In other words, when a plurality of third lands 25 and a plurality of fourth lands 27 are provided, they are arranged side by side in the direction along the short side of the substrate 19.

[0031] In the electronic substrate 13, the first land 21 is disposed within an area that is 80% of the center-to-center distance between the third land 25 and the fourth land 27 (see FIG. 6). Moreover, the electronic substrate 13 is formed so that the area of ​​the third land 25 is equal to or smaller than the area of ​​the fourth land 27.

[0032] FIG. 3 is a schematic diagram showing a cross section taken along line 3-3 of an example of the electronic substrate 13 shown in FIG.

[0033] In the electronic board 13, a first signal line 33 is connected to each of the multiple first lands 21. Each of the multiple first lands 21 and each of the multiple first signal lines 33 are connected by, for example, solder. A second signal line 35 is connected to the second land 23. The second land 23 and the second signal line 35 are connected by, for example, solder. The third land 25 and the fourth land 27 are connected to the same shielding conductor 37. The shielding conductor 37 is made of a box-shaped conductor that is open at least at the bottom.

[0034] The shielding conductor 37 according to the first embodiment is formed in a cylindrical shape so as to cover the first lands 21 and the first signal lines 33. The shielding conductor 37 at the 3-3 cross section in FIG. 2 is connected between the third land 25 and the fourth land 27 by solder or the like. That is, the shielding conductor 37 is connected to the ground 31 via the third land 25 and the fourth land 27, and has the same potential as the ground 31. As a result, the first land 21 and the first signal line 33 are electromagnetically shielded by the shielding conductor 37. The connection portions between the third land 25 and the fourth land 27 and the shielding conductor 37 by solder or the like become contact points 39, which will be described later. Generally, the entire circumference of the shielding conductor 37 is not connected to the ground 31, that is, the shielding conductor 37 and the ground 31 are connected at multiple points, and multiple gaps are generated at the points where they are not connected.

[0035] In the electronic board 13, gaps 41 are provided between the outer circumference of each of the first lands 21 and the second land 23 and the ground 31, and connection between the ground 31, the third land 25, and the fourth land 27 is avoided. Each of the gaps 41 includes a clearance 45 of a predetermined distance in addition to an insulating gap 43 for avoiding coupling between adjacent lands or with the ground. The insulating gap 43 is usually formed to be about 0.1 mm. The clearance 45 for facilitating the generation of a magnetic field loop, which will be described later, is set to a predetermined distance, for example, about 0.2 to 0.4 mm. Each of the gaps 41 is preferably provided to be 0.3 mm to 0.5 mm, but is not limited thereto. For example, when the electronic board 13 according to the first embodiment is sufficiently large, each of the gaps 41 may be provided to be larger than 0.5 mm.

[0036] Furthermore, each of the plurality of clearances 45 does not have to be uniform on each side of each of the plurality of first lands 21, the second land 23, the third land 25, and the fourth land 27. Each of the plurality of clearances 45 may be provided so that each of the plurality of gaps 41 including the insulating gap 43 is 0.3 mm to 0.5 mm, as described above. In other words, the worker who manufactures the substrate 19 according to the first embodiment only needs to arrange (connect) each of the lands so that each of the plurality of gaps 41 including the clearance 45 and the insulating gap 43 is 0.3 mm to 0.5 mm, which can improve the efficiency of the arrangement (connection) work of each land.

[0037] The substrate 19 in the electronic substrate 13 has a bottom surface 47 opposite to the top surface 29, and a ground 31 covering the bottom surface 47. The ground 31 is provided with a plurality of ground cut-out portions 49 corresponding to the positions of each of the plurality of first lands 21 and the second land 23. This allows the electronic substrate 13 to avoid connection (contact) between the ground 31 and each of the plurality of first lands 21 and the second land 23 by each of the plurality of ground cut-out portions 49.

[0038] FIG. 4A is a plan view showing an example of a state in which a magnetic field loop occurs in an electronic board 51 according to a comparative example, and FIG. 4B is a schematic diagram showing a cross section taken along line 4B-4B of FIG. 4A.

[0039] In the electronic board 51 according to the comparative example shown in FIG. 4A, an image transmission pin (not shown) of the camera 11 that outputs a high-speed signal is connected to each of the first lands 21 by, for example, a via hole penetrating the electronic board 51. In the electronic board 51, a control signal pin (not shown) that transmits a low-speed signal is connected to the second land 23. Each of the first lands 21 according to the comparative example is connected to each of the first signal lines 33 on the upper surface 29 of the board 19. In addition, the second land 23 according to the comparative example shown in FIG. 5 is connected to the second signal line 35 on the upper surface 29 of the board 19.

[0040] In the electronic board 51 according to the comparative example, noise in the video signal in the high-speed signal generated from each of the multiple first signal lines 33 jumps into the second signal line 35. This causes the second signal line 35 to function as an antenna and generate radiated noise. When the second signal line 35 receives an external radio wave, it becomes an antenna and causes the generated radiated noise to jump into the video signal of each of the multiple first signal lines 33, causing image disturbance.

[0041] In addition, in the electronic board 51 according to the comparative example, the system to which each of the first signal lines 33 (video transmission cables) connected to each of the first lands 21 is connected is different from the system to which the second signal line 35 (vehicle control cable) connected to the second land 23 is connected, so each of the first lands 21 and the second land 23, which are connected to different destinations, cannot be covered with the same shielding conductor 37. Furthermore, video signals are usually signals that are communicated at high speed, and there are concerns about the influence of noise. Therefore, as described above, it is necessary to provide a shielding conductor that shields noise. Note that control signals are signals that are communicated at low speed, and are generally less affected by noise, so shielding is not necessarily required (i.e., it is not essential).

[0042] Therefore, as in the electronic board 51 of the comparative example, when multiple lands on the same board are connected to different systems and one of the lands includes a video signal communicated at high speed, there is a possibility that noise will be emitted from the video signal or the video signal will be disrupted by external radio waves.

[0043] However, the electronic board 51 according to the comparative example described above is provided with only one contact point 39 that conducts (connects) the shielding conductor 37 and the third land 25. At this time, a common mode current generates one magnetic field loop 55 shown in Fig. 4A centered on the contact point 39 that connects the ground 31 and the shielding conductor 37. Therefore, in the electronic board 51 according to the comparative example, noise is introduced into the video transmission cable (each of the multiple first signal lines 33) due to the magnetic field loop 55, making it difficult to suppress the effects of noise.

[0044] FIG. 5 is an explanatory diagram showing, in a plan view, an example of a state in which a magnetic field loop 55 is generated in the electronic board 13 according to the first embodiment.

[0045] In the electronic board 13 according to the first embodiment, a third land 25 connected to the ground 31 is arranged between each of the multiple first lands 21 and the second land 23, and a fourth land 27 connected to the ground 31 is arranged on the opposite side of the third land 25 across the first land 21. The third land 25 and the fourth land 27 shown in FIG. 5 are arranged symmetrically across the first land 21. That is, in the electronic board 13 according to the first embodiment, the contact points 39 between the ground 31 and the shielding conductor 37 are arranged symmetrically across the first land 21. As a result, in the electronic board 13, magnetic field loops 55 are generated that rotate in the same direction around the two contact points 39 that connect the third land 25 arranged on the left side of the multiple first lands 21 and the fourth land 27 arranged on the right side of the multiple first lands 21 to the shielding conductor 37.

[0046] The arrangement of the third land 25 and the fourth land 27 is not limited to the bilateral symmetry described above. The third land 25 and the fourth land 27 may be arranged so as to cancel out the magnetic field loops originating from each other. For example, the third land 25 and the fourth land 27 may be arranged line-symmetrically with respect to a line that passes through the midpoints of the multiple first lands 21 shown in FIG. 2 and is perpendicular to the 3-3 cross section line. The third land 25 and the fourth land 27 may also be arranged line-symmetrically with respect to the 3-3 cross section line.

[0047] The two magnetic field loops 55 generate magnetic fields in opposite directions and cancel each other out in the portion where the multiple first lands 21 are arranged (i.e., inside the shielding conductor 37). In other words, by generating the two magnetic field loops 55, the electronic board 13 can cancel out the magnetic field loops 55 generated by the common mode current in the portion where the multiple first lands 21 are arranged (i.e., inside the shielding conductor 37).

[0048] As a result, the electronic board 13 according to the first embodiment can reduce noise generated from the second signal lines 35 for each of the multiple first signal lines 33. Furthermore, the electronic board 13 can suppress the influence of noise even when it is impossible to cover the circuit board with the same shielding conductor 37 or when only a portion of the wiring can be covered with the shielding conductor 37 in an incomplete state. As a result, the electronic board 13 can improve low-noise and noise-resistant performance.

[0049] Furthermore, the electronic board 13 of embodiment 1 can suppress noise radiation from the video signal and suppress disturbance of the video signal due to external radio waves, even when multiple lands on the same board are connected to different systems and one of the systems includes a video signal communicated at high speed.

[0050] FIG. 6 is an explanatory diagram showing an example of the correlation between the distance and the magnetic field attenuation amount by each of the two magnetic field loops 55. In FIG.

[0051] The electronic substrate 13 is arranged so that each of the multiple first lands 21 is located within an area (i.e., an area 0.8D shown in FIG. 6) that is 80% of the center-to-center distance D between the third land 25 and the fourth land 27. The position of the midpoint (0.8D) / 2 of the area 0.8D coincides with the position of the midpoint D / 2 of the center-to-center distance D.

[0052] When a current flows through a wiring of finite length, the magnetic field strength H at a point P a distance R away from the wiring is H=(cosθ1+cosθ2) / 4πR, and is inversely proportional to the distance R. Therefore, the magnetic field strength H is maximum at the midpoint D / 2 of each of the first lands 21, and decreases with increasing distance from this center position toward the third land 25 or the fourth land 27.

[0053] Two magnetic field loops 55 (see FIG. 5) generated around the third land 25 and the fourth land 27, respectively, have the same magnetic field strength at the center of each of the first lands 21, and are opposite in direction, so they cancel each other out. As shown in FIG. 6, the magnetic field strength H of each of the third land 25 and the fourth land 27 is opposite in direction and equal in strength at the midpoint D / 2 of the center distance D.

[0054] The electronic board 13 ensures the effectiveness of the noise reduction effect by arranging each of the multiple first lands 21 so as to be located within an area that is 80% of the center-to-center distance D between the third land 25 and the fourth land 27 (i.e., area 0.8D shown in Fig. 6). In other words, the electronic board 13 is configured to ensure the effectiveness of the noise reduction effect by each of the two magnetic field loops 55 by arranging each of the multiple first lands 21 so as to be located within area 0.8D shown in Fig. 6.

[0055] As described above, the electronic board 13 of embodiment 1 comprises a board 19 having a ground 31, a first land 21 formed on an upper surface 29 of the board 19 and connected to a first signal line 33, a second land 23 formed on the upper surface 29 and connected to a second signal line 35, a third land 25 disposed on the upper surface 29 between the first land 21 and the second land 23 and connected to the ground 31, and a fourth land 27 disposed on the upper surface 29 opposite the third land 25 across the first land 21 and connected to the ground 31.

[0056] As a result, in the electronic board 13 according to the first embodiment, the board 19 has a ground 31. The ground 31 is provided, for example, covering the upper surface 29 of the board 19. Four types of lands are arranged in a row on the upper surface 29 of the board 19. The four types of lands are arranged in the following order from one end side to the other end side of the board 19: the second land 23, the third land 25, the first land 21, and the fourth land 27. In the first embodiment, two first lands 21 are provided. Therefore, five lands are lined up.

[0057] Of these, a first signal line 33, for example a video transmission cable, is connected to the first land 21. A second signal line 35, for example a vehicle control cable, is connected to the second land 23.

[0058] The first land 21 and the second land 23 are insulated from the ground 31. The insulation between the ground 31 and the land is made possible by separating the ground 31 covering the upper surface 29 of the substrate 19 from the outer periphery of the land at the position of each land. In this case, the gap 41 formed between the periphery of the land and the ground 31 includes an insulating gap 43.

[0059] On the other hand, the third land 25 and the fourth land 27 arranged on both sides of the two first signal lines 33 are connected to the ground 31. The connection between these lands and the ground 31 is made possible by leaving a part of the outer periphery of each land connected to the ground 31.

[0060] Therefore, the electronic board 13 of embodiment 1 can suppress noise radiation from the video signal and suppress disturbance of the video signal due to external radio waves, even when multiple lands on the same board are connected to different systems and one of the lands includes a video signal communicated at high speed.

[0061] Furthermore, in electronic board 13 according to embodiment 1, the first land is disposed within an area that is 80% of the center-to-center distance between the third land and the fourth land. This ensures that electronic board 13 according to embodiment 1 can effectively reduce noise by each of two magnetic field loops 55.

[0062] In addition, in the electronic board 13 according to the first embodiment, the first land 21 and the second land 23 are formed with a gap 41 between the periphery of each land and the ground 31. This gap 41 includes an insulating gap 43 and a clearance 45. The insulating gap 43 is provided to prevent a short circuit between the land and the ground 31, and is usually formed to be about 0.1 mm. The clearance 45 is provided separately from the insulating gap 43 to facilitate the generation of the magnetic field loop 55, and is set to about 0.2 to 0.4 mm. That is, in the electronic board 13, the gap 41 of about 0.3 to 0.5 mm is set between the periphery of the first land 21 and the second land 23 and the ground 31. As a result, the electronic board 13 facilitates the generation of the magnetic field loop 55 (in other words, makes it difficult for the magnetic field loop 55 to be coupled with the ground 31), and facilitates the noise reduction effect. It goes without saying that the insulating gap 43 and the clearance 45 are not limited to the above-mentioned values.

[0063] Furthermore, in the electronic board 13 according to the first embodiment, the board 19 has a ground 31 covering a bottom surface 47 opposite to the top surface 29. The ground 31 on the bottom surface 47 is removed at positions corresponding to the first land 21 and the second land 23. This makes it difficult for the magnetic field loop 55 to couple with the ground 31 even on the bottom surface 47 of the board 19 in the electronic board 13. As a result, the magnetic field loop 55 is more likely to occur, making it easier to obtain a noise reduction effect.

[0064] Furthermore, the substrate 19 is formed to be thin. In the thin substrate 19, for example, the second signal line 35 connected to the second land 23 is coupled with the ground 31 on the lower surface 47 provided directly below it, causing a phenomenon in which noise spreads. In the electronic substrate 13, the ground 31 on the lower surface 47 is removed at a position corresponding to the first land 21 and the second land 23, so that the spread of noise caused by the ground 31 provided on the lower surface 47 can be suppressed.

[0065] In addition, in the electronic board 13 according to the first embodiment, the first land 21 and the second land 23 have a gap 41 between the outer periphery of each land and the ground 31. The gap 41 is made up of an insulating gap 43 for avoiding coupling and a clearance 45 of a predetermined distance. The insulating gap 43 is usually formed to be about 0.1 mm. The clearance 45 for facilitating the generation of the magnetic field loop 55 is a predetermined distance, and is set to, for example, about 0.2 to 0.4 mm. The clearance 45 only needs to be secured at a predetermined distance, and does not need to be formed evenly. This allows the electronic board 13 to relax the processing accuracy required when forming the lands.

[0066] The electronic substrate 13 has at least one of the first land 21, the second land 23, the third land 25, and the fourth land 27 in plural.

[0067] Moreover, the electronic board 13 according to the first embodiment is provided with a plurality of any lands among the first land 21, the second land 23, the third land 25, and the fourth land 27. For example, the first land 21 to which the first signal line 33, which is a video transmission cable, is connected may be provided in two, thereby enabling balanced transmission using two video signals with a phase difference of 180°. Thus, the electronic board 13 can reduce radiation and be less susceptible to external noise by performing balanced transmission.

[0068] In the electronic substrate 13, the third lands 25 and the fourth lands 27, each of which is arranged in a plurality, are arranged side by side in a direction intersecting a line passing through one third land 25 and one fourth land 27.

[0069] Moreover, the electronic board 13 according to the first embodiment has a plurality of third lands 25 and a plurality of fourth lands 27 arranged. In this case, the plurality of third lands 25 and the plurality of fourth lands 27 are arranged in a direction intersecting a line passing through one third land 25 and one fourth land 27. That is, the plurality of third lands 25 and the plurality of fourth lands 27 are arranged so as not to be arranged in a straight line. For example, when two third lands 25 and two fourth lands 27 are arranged, the third lands 25 are arranged at each of a pair of adjacent corners of a rectangle, and the fourth lands 27 are arranged at each of the other pair of adjacent corners. As a result, the electronic board 13 can increase the cancellation effect of the magnetic field loop and obtain a greater noise reduction effect, compared to the case where there is one each of the third land 25 and the fourth land 27.

[0070] Furthermore, in the electronic substrate 13 according to the first embodiment, the third land 25 is disposed between the first land 21 and the second land 23. As a result, when the third land 25 is formed with an area equal to or smaller than that of the fourth land 27, it is possible to prevent the third land 25 from interfering with other elements or lands (for example, the first land 21 or the second land 23).

[0071] Although various embodiments have been described above with reference to the drawings, it goes without saying that the present disclosure is not limited to such examples. It is clear that a person skilled in the art can conceive of various modifications, corrections, substitutions, additions, deletions, and equivalents within the scope of the claims, and it is understood that these also naturally belong to the technical scope of the present disclosure. In addition, the components in the various embodiments described above may be arbitrarily combined within the scope of the invention. [Industrial Applicability]

[0072] The present disclosure is useful as an electronic substrate that suppresses the effects of noise. [Explanation of symbols]

[0073] 13 Electronic Board 19 Substrate 21 The First Land 23 The Second Land 25 The Third Land 27 The Fourth Land 29 Top side 31 Grand 33 First signal line 35 Second signal line 41 Gap 43 Insulation gap 45 Clearance 47 Bottom side 49 Ground cutout D Center distance

Claims

1. a substrate having a top surface ground on its top surface; At least one first land formed on the top surface and connected to a first signal line; at least one second land formed on the top surface and connected to a second signal line; at least one third land disposed on the top surface between the at least one first land and the at least one second land and connected to the top surface ground; at least one fourth land is disposed on the top surface opposite the at least one third land across the at least one first land, and is connected to the top surface ground; the substrate further includes a shielding conductor for electromagnetically shielding the at least one first land and the first signal line; the shield conductor is connected to the at least one third land at a first contact; the shield conductor is connected to the at least one fourth land at a second contact; the at least one third land and the at least one fourth land are arranged so that a first magnetic field loop generated around the first contact and a second magnetic field loop generated around the second contact and rotating in the same direction as the first magnetic field loop cancel each other out. Electronic board.

2. The at least one third land and the at least one fourth land are arranged symmetrically on either side of the at least one first land. The electronic substrate according to claim 1 .

3. The shielding conductor is formed in a cylindrical shape so as to cover the at least one first land and a portion of the first signal line. The electronic substrate according to claim 1 .

4. The at least one first land is disposed within an area that is 80% of a center-to-center distance between the at least one third land and the at least one fourth land. The electronic substrate according to claim 1 .

5. a gap provided between an outer periphery of each of the at least one first land and the at least one second land and the upper surface ground includes a clearance of a predetermined distance; The electronic substrate according to any one of claims 1 to 3.

6. the substrate has a bottom ground covering a bottom surface opposite to the top surface, the bottom ground is not present at a position corresponding to the at least one first land and the at least one second land; The electronic substrate according to any one of claims 1 to 5.

7. The clearance is not uniform. The electronic substrate according to claim 5 .

8. At least one of the at least one first land, the at least one second land, the at least one third land, and the at least one fourth land is a plurality of land. The electronic substrate according to any one of claims 1 to 7.

9. the plurality of third lands or the plurality of fourth lands are arranged side by side in a direction intersecting a line passing through one of the plurality of third lands and one of the plurality of fourth lands; The electronic substrate according to claim 8 .

10. an area of ​​the at least one third land is equal to or less than an area of ​​the at least one fourth land; The electronic substrate according to any one of claims 1 to 9.

11. An electronic device comprising the electronic substrate according to any one of claims 1 to 10. In-car camera.

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