Electronic modules and electronic equipment

Abstract

The present invention provides an electronic module that can suppress the arrival of magnetic fields over a wider range of circuits. [Solution] The electronic module includes a printed circuit board having first and second surfaces, a first inductor element having a first coil and positioned on the first surface such that the direction of the winding axis of the first coil intersects the first surface, a second inductor element having a second coil and positioned on the first surface such that the direction of the winding axis of the second coil intersects the first surface, and a third inductor element having a third coil, wherein the first and second inductor elements are arranged such that the magnetic fields of them are opposite to each other when energized, and the third inductor element is arranged such that the direction of the winding axis of the third coil is parallel to the second direction, and when energized, the polarity of the magnetic pole at the end of the third coil closer to the first inductor element in the second direction is always opposite to the polarity of the magnetic pole at the end of the first coil closer to the third inductor element in the first direction.

Description

Technical Field

[0001] The present invention relates to electronic modules and electronic devices.

Background Art

[0002] In electronic devices equipped with an image sensor, such as digital cameras and smartphones, when magnetic field noise links with the image sensor, disturbance occurs in captured images due to the magnetic field noise. In recent years, with the improvement of ISO sensitivity, even weak magnetic field noise that did not cause problems in the past can now cause image disturbance. Additionally, along with the increase in the number of pixels, the current required for driving the image sensor has also increased. To suppress power loss in current supply, an increasing number of cases involve mounting a power supply circuit near the image sensor. A key challenge is suppressing image disturbance of the image sensor caused by magnetic field noise from the inductor circuit used in the power supply circuit.

[0003] Patent Document 1 discloses a configuration where an inductor circuit is formed of two inductor components, which are mounted on one surface of a printed wiring board and configured such that opposite magnetic fields are generated when energized to cancel each other out, thereby suppressing the influence of magnetic fields on circuits such as image sensors.

Prior Art Literature

Patent Literature

[0004]

Patent Document 1

Summary of the Invention

Problem to be Solved by the Invention

[0005] Patent Document 1 describes a configuration that only exhibits a magnetic field suppression effect on circuits and wiring located on the orthogonal plane of the midpoint of the line segment connecting the centers of two inductor components. In other words, the configuration in Patent Document 1 did not provide sufficient noise reduction for circuits and wiring located away from symmetrical positions from the two coils. Therefore, there is a need for a technology that suppresses magnetic fields over a wide area, not just at specific locations.

[0006] The object of the present invention is to provide an electronic module and electronic device that can suppress the arrival of a magnetic field over a wider range of circuits. [Means for solving the problem]

[0007] According to one aspect of the present disclosure, a printed circuit board having a first surface and a second surface facing each other, a first inductor element having a first coil and disposed on the first surface such that the direction of the winding axis of the first coil intersects the first surface, a second inductor element having a second coil and disposed on the first surface such that the direction of the winding axis of the second coil intersects the first surface, and a third inductor element having a third coil, wherein the first inductor element, the second inductor element and the third inductor element are configured to always generate currents in phase when energized, the first inductor element and the second inductor element are arranged such that when energized, the first magnetic field generated by the first coil in a first direction intersecting the first surface and the second magnetic field generated by the second coil in the first direction are in opposite directions, and the third inductor element is configured such that, in the first direction, the center point of the first inductor element and the center point of the second inductor element are opposite to each other An electronic module is provided which is provided in a range between the center point closer to one plane and the second plane, and in a second direction connecting the center point of the first inductor element and the center point of the second inductor element, is provided in a range between the center point of the first inductor element and the center point of the second inductor element, and is arranged such that the direction of the winding axis of the third coil is parallel to the second direction, and when energized, the polarity of the magnetic pole of the end of the third coil closer to the first inductor element in the second direction is the opposite polarity of the magnetic pole of the end of the first coil closer to the third inductor element in the first direction, and when energized, the polarity of the magnetic pole of the end of the third coil closer to the second inductor element in the second direction is the opposite polarity of the magnetic pole of the end of the second coil closer to the third inductor element in the first direction. [Effects of the Invention]

[0008] According to this disclosure, it is possible to provide a circuit board and electronic device that can suppress the arrival of magnetic fields over a wider range of circuits. [Brief explanation of the drawing]

[0009] [Figure 1] This is a schematic diagram showing an imaging device, which is an example of an electronic device according to the first embodiment. [Figure 2A] This is a plan view showing a sensor module according to the first embodiment. [Figure 2B] This is a cross-sectional view showing a sensor module according to the first embodiment. [Figure 3A] This is a perspective view showing an inductor circuit according to the first embodiment. [Figure 3B] This is a plan view showing an inductor circuit according to the first embodiment. [Figure 3C] This is a cross-sectional view showing an inductor circuit according to the first embodiment. [Figure 3D] This is a cross-sectional view showing an inductor circuit according to the first embodiment. [Figure 4] This graph shows the calculation results of the magnetic flux density distribution in Example 1 and the Comparative Example. [Figure 5A] This is a plan view showing a sensor module according to the second embodiment. [Figure 5B] This is a cross-sectional view showing a sensor module according to the second embodiment. [Figure 6A] This is a perspective view showing an inductor circuit according to the second embodiment. [Figure 6B] This is a plan view showing an inductor circuit according to the second embodiment. [Figure 6C] This is a cross-sectional view showing an inductor circuit according to the second embodiment. [Figure 6D] This is a cross-sectional view showing an inductor circuit according to the second embodiment. [Figure 7] This graph shows the calculation results of the magnetic flux density distribution in Example 2 and the Comparative Example. [Figure 8A] This is a schematic diagram showing a modified connection configuration of an inductor circuit according to another embodiment. [Figure 8B] This is a schematic diagram showing a modified connection configuration of an inductor circuit according to another embodiment. [Figure 8C]It is a schematic diagram showing a modification of the connection configuration of an inductor circuit according to another embodiment. [Figure 8D] It is a schematic diagram showing a modification of the connection configuration of an inductor circuit according to another embodiment. [Figure 8E] It is a schematic diagram showing a modification of the connection configuration of an inductor circuit according to another embodiment. [Figure 8F] It is a schematic diagram showing a modification of the connection configuration of an inductor circuit according to another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] [First Embodiment] An electronic device according to a first embodiment of the present invention will be described with reference to FIG. 1. FIG. 1 is a schematic diagram showing a digital camera 1 which is an image pickup apparatus as an example of the electronic device according to the present embodiment.

[0011] As shown in FIG. 1, the digital camera 1 serving as the image pickup apparatus is an interchangeable-lens digital camera, and includes a camera body 2. A lens unit (lens barrel) 3 including a lens is detachably attachable to the camera body 2. The camera body 2 includes a housing 4, a processing module 5, a sensor module 6, a cable 7, and a battery 8. The processing module 5, the sensor module 6, the cable 7, and the battery 8 are arranged inside the housing 4.

[0012] The processing module 5 is an example of an electronic module, and includes a printed wiring board 10 and an electronic component 12. The electronic component 12 is mounted and installed on the printed wiring board 10. The processing module 5 is electrically connected to the sensor module 6 via the cable 7.

[0013] The sensor module 6 is an example of an electronic module and comprises a printed circuit board 11, an image sensor 9 which is an imaging device, a power supply circuit 13, and electronic components 14. The image sensor 9 is mounted on one side of the printed circuit board 11. The power supply circuit 13 and electronic components 14 are mounted on the other side of the printed circuit board 11. The image sensor 9 is, for example, a CMOS (Complementary Metal Oxide Semiconductor) image sensor or a CCD (Charge Coupled Device) image sensor. The image sensor 9 is a circuit that has the function of converting light incident via the lens unit 3 into an electrical signal. The power supply circuit 13 supplies power at a predetermined voltage necessary for the operation of components such as the image sensor 9 and electronic components 14. By mounting the power supply circuit 13 on the printed circuit board 11 instead of the printed circuit board 10, it is possible to suppress power loss through the cable 7. The battery 8 is a power supply that supplies power to the processing module 5, the sensor module 6, etc.

[0014] Next, a sensor module 6, which is an example of an electronic module according to this embodiment, will be described using Figures 2A and 2B. Figures 2A and 2B are schematic diagrams showing in detail the sensor module 6 according to this embodiment in the digital camera 1 shown in Figure 1. Figure 2A is a plan view of the sensor module 6 as seen from the +Z direction. Figure 2B is a cross-sectional view showing a section along the dashed line A100-A'100 in Figure 2A.

[0015] As shown in Figures 2A and 2B, the printed circuit board 11 in the sensor module 6 according to this embodiment has a first surface 11a and a second surface 11b that are parallel to each other and face each other. A power supply circuit 13 is arranged and mounted on the first surface 11a. An image sensor 9, which is a semiconductor element, is arranged and mounted on the second surface 11b. The printed circuit board 11 has a rectangular planar shape. The image sensor 9 has a rectangular planar shape that is smaller than the printed circuit board 11. The image sensor 9 is arranged so that its long side and short side are aligned with the long side and short side of the printed circuit board 11, respectively. In the following description, a right-handed XYZ coordinate system is used, and the direction perpendicular to the first surface 11a and the second surface 11b is defined as the Z direction, with the direction facing outwards from the printed circuit board 11 relative to the first surface 11a being defined as the +Z direction. Furthermore, among the directions perpendicular to the Z direction, the direction parallel to the long side of the printed circuit board 11 is defined as the X direction, and the direction parallel to the short side of the printed circuit board 11 is defined as the Y direction.

[0016] Furthermore, other circuits, semiconductor elements, electronic components, etc. may be arranged and mounted on the first surface 11a of the printed circuit board 11, either together with the power supply circuit 13 or in place of the power supply circuit 13. Also, other circuits, semiconductor elements, electronic components, etc. may be arranged and mounted on the second surface 11b of the printed circuit board 11, either together with the image sensor 9 or in place of the image sensor 9.

[0017] The power supply circuit 13 includes an input terminal 101, an output terminal 102, a power supply control IC (Integrated Circuit) 103, an inductor circuit 104, a capacitor component 105, wirings 106, 107, and 108, and ground wirings 109 and 110. The input terminal 101 is connected to one end of wiring 106. The other end of wiring 106 is connected to one terminal of the power supply control IC 103. The other terminal of the power supply control IC 103 is connected to one end of wiring 107. The other end of wiring 107 is connected to one end of the inductor circuit 104. The other end of the inductor circuit 104 is connected to one end of wiring 108. The other end of wiring 108 is connected to the output terminal 102. One of the two terminals of the capacitor component 105 is connected to wiring 108. The other terminal of the two terminals of the capacitor component 105 is connected to ground wiring 110. The power control IC 103, a circuit component that controls power, incorporates, for example, a power semiconductor device and converts the power input from the input terminal 101 into a predetermined voltage by time-division switching. The voltage converted by the power control IC 103 is filtered by the inductor circuit 104 and the capacitor component 105 and output as a stable low voltage from the output terminal 102. In this way, the low voltage power generated by the power supply circuit 13 is supplied to load devices such as the image sensor 9.

[0018] The inductor circuit 104 includes a first inductor element 111, a second inductor element 112, and a third inductor element 113. The first inductor element 111, the second inductor element 112, and the third inductor element 113 are electrically connected. One of the two terminals of the first inductor element 111 corresponds to one end of the inductor circuit 104 and is connected to the other end of the wiring 107. One of the two terminals of the second inductor element 112 corresponds to the other end of the inductor circuit 104 and is connected to one end of the wiring 108. One of the two terminals of the third inductor element 113 is connected to the other terminal of the first inductor element 111. The other terminal of the third inductor element 113 is connected to the other terminal of the second inductor element 112. Thus, the first inductor element 111, the second inductor element 112, and the third inductor element 113 are sequentially connected in series from the power control IC 103 side to the output terminal 102 side, forming a series connection circuit. The first inductor element 111, the second inductor element 112, and the third inductor element 113 are connected in series, or they may be connected in parallel or in series-parallel.

[0019] In a plan view in the Z direction, the first inductor element 111, the second inductor element 112, and the third inductor element 113 are arranged to overlap with the image sensor 9.

[0020] As shown in Figure 2B, the first inductor element 111 and the second inductor element 112 are provided on the first surface 11a of the printed circuit board 11, while the third inductor element 113 is provided inside the printed circuit board 11. It is not necessary for the entire third inductor element 113 to be provided inside the printed circuit board 11; at least a portion of the third inductor element 113 must be provided inside the printed circuit board 11.

[0021] Next, the first inductor element 111, the second inductor element 112, and the third inductor element 113, which constitute the inductor circuit 104, will be described in detail using Figures 3A to 3D. Figures 3A to 3D are schematic diagrams showing the area of ​​the inductor circuit 104 enclosed by dashed lines in Figures 2A and 2B, including the printed circuit board 11 and the image sensor 9. Figure 3A is a perspective view. Figure 3B is a plan view of Figure 3A from the +Z direction. Figure 3C is a cross-sectional view showing a section along the dashed line A101-A'101 in Figure 3B. Figure 3D is a cross-sectional view showing a section along the dashed line A102-A'102 in Figure 3B.

[0022] As shown in Figures 3A to 3D, the first inductor element 111 and the second inductor element 112 are arranged so as to be aligned in the X direction on the first surface 11a of the printed circuit board 11. The first inductor element 111 and the second inductor element 112 may have the same structure. In this case, the direction connecting the center point of the first inductor element 111 and the center point of the second inductor element 112 is the X direction, where the first inductor element 111 and the second inductor element 112 are aligned. The third inductor element 113 is arranged inside the printed circuit board 11 and on the first surface 11a between the first inductor element 111 and the second inductor element 112, which are aligned in the X direction. Thus, the first inductor element 111, the third inductor element 113, and the second inductor element 112 are arranged in this order so as to be aligned in the +X direction.

[0023] The first inductor element 111 is, for example, an inductor component and comprises a coil 111A, a magnetic material 111B, and electrodes 111C and 111D. The coil 111A is formed of a helical conductor. The helical coil 111A is embedded in the magnetic material 111B such that the direction of its winding axis is parallel to the Z direction, that is, the direction of its winding axis is perpendicular to the first surface 11a. The coil 111A only needs to be positioned so that the direction of its winding axis intersects the first surface 11a. Both ends of the coil 111A are connected to electrodes 111C and 111D, respectively. Electrodes 111C and 111D are one terminal and the other terminal of the first inductor element 111, respectively. Electrodes 111C and 111D are electrically connected to conductive pads 111E and 111F formed on the first surface 11a of the printed circuit board 11, respectively. The means of electrically connecting electrodes 111C and 111D to conductive pads 111E and 111F, respectively, are not particularly limited, but one example is soldering. The other end of wiring 107 is connected to conductive pad 111E.

[0024] The second inductor element 112 is, for example, an inductor component and includes a coil 112A, a magnetic material 112B, and electrodes 112C and 112D. The coil 112A is formed of a helical conductor. The helical coil 112A is embedded in the magnetic material 112B so that its winding axis is parallel to the Z direction, that is, the direction of the winding axis is perpendicular to the first surface 11a. The coil 112A only needs to be positioned so that the direction of its winding axis intersects the first surface 11a. Both ends of the coil 112A are connected to electrodes 112C and 112D, respectively. Electrodes 112C and 112D are one terminal and the other terminal of the second inductor element 112, respectively. Electrodes 112C and 112D are electrically connected to conductive pads 112E and 112F formed on the first surface 11a of the printed circuit board 11, respectively. The means of electrically connecting electrodes 112C and 112D to conductive pads 112E and 112F, respectively, are not particularly limited, but one example is soldering. One end of wiring 108 is connected to conductive pad 112E.

[0025] The first and second inductor elements 111 and 112 are arranged on the first surface 11a such that the winding shafts of the coils 111A and 112A are parallel to the Z direction, but the arrangement of the first and second inductor elements 111 and 112 is not limited to this. The first inductor element 111 only needs to be arranged on the first surface 11a such that the winding shaft of the coil 111A is parallel to the direction in which it intersects the first surface 11a. Similarly, the second inductor element 112 only needs to be arranged on the first surface 11a such that the winding shaft of the coil 112A is parallel to the direction in which it intersects the first surface 11a.

[0026] The third inductor element 113 has a coil 113D formed by a plurality of wires 113A, a plurality of wires 113B, and a plurality of vias 113C. The wires 113A are formed on the first surface 11a of the printed circuit board 11. The wires 113B are formed in the inner layer of the printed circuit board 11 parallel to the XY plane, i.e., parallel to the first surface 11a. The vias 113C are formed in the inner layer of the printed circuit board 11 parallel to the Z direction. The plurality of wires 113A, a plurality of wires 113B, and a plurality of vias 113C are repeatedly connected in the order of wires 113A, vias 113C, wires 113B, and vias 113C to form a helical coil 113D. The helical coil 113D is arranged so that its winding axis is parallel to the X direction. Of the multiple wires 113A, one end of the outer wire 113A on the side of the first inductor element 111 is connected to the conductive pad 111F, and one end of the outer wire 113A on the side of the second inductor element 112 is connected to the conductive pad 112F.

[0027] In the third inductor element 113, a portion of the wiring 113B and vias 113C are provided and arranged inside the printed circuit board 11. However, the structure of the third inductor element 113 on the printed circuit board 11 is not limited to this. The entire third inductor element 113, i.e., the wiring 113A, wiring 113B, and vias 113C, may be provided and arranged inside the printed circuit board 11.

[0028] Furthermore, the third inductor element 113 only needs to be provided in the Z direction within the range from the center point of the first inductor element 111 and the center point of the second inductor element 112 that is closer to the first surface 11a, to the second surface 11b. The first inductor element 111 and the second inductor element 112 may have the same structure, in which case the positions of their center points in the Z direction are the same.

[0029] Furthermore, the third inductor element 113 only needs to be provided within the range between the center point of the first inductor element 111 and the center point of the second inductor element 112, in the direction connecting the center point of the first inductor element 111 and the center point of the second inductor element 112. The first inductor element 111 and the second inductor element 112 may have the same structure, in which case the direction connecting the center point of the first inductor element 111 and the center point of the second inductor element 112 will be the X direction.

[0030] Furthermore, the third inductor element 113 is positioned on the first surface 11a such that the winding axis of the coil 113D is parallel to the X direction, but the positioning of the third inductor element 113 is not limited to this. The third inductor element 113 only needs to be positioned such that the direction of the winding axis of the coil 113D is parallel to the direction connecting the center point of the first inductor element 111 and the center point of the second inductor element 112.

[0031] In this way, a series connection circuit of the first inductor element 111, the second inductor element 112, and the third inductor element 113 is formed between wiring 107 and wiring 108.

[0032] As shown in Figures 3A and 3B, the currents 107J, 113J, and 108J generated in wirings 107, 108, and inductor circuit 104 are indicated by arrows. These currents 107J, 113J, and 108J contain both DC and AC components. Current 107J is the current generated in wiring 107. Current 113J is the current generated in the third inductor element 113. Current 108J is the current generated in wiring 108. The directions of the three arrows for currents 107J, 113J, and 108J indicate that they are in the same phase relationship in the direction of the arrow at each frequency of the AC component. In this way, the first inductor element 111, the second inductor element 112, and the third inductor element 113 are configured to always generate currents in the same phase when energized.

[0033] Consider the case where currents 107J, 113J, and 108J are generated in the direction of the arrows with the same phase relationship shown in the diagram, at a frequency with an AC component. In this case, the first inductor element 111, the second inductor element 112, and the third inductor element 113 generate magnetic fields 111H, 112H, and 113H, respectively, in the direction of the arrows.

[0034] Specifically, the coil 111A of the first inductor element 111 generates a magnetic field 111H in the +Z direction. The coil 112A of the second inductor element 112 generates a magnetic field 112H in the -Z direction, which is opposite to the direction of the magnetic field 111H. Thus, the first inductor element 111 and the second inductor element 112 are arranged such that, when energized, the magnetic field generated by coil 111A in the Z direction and the magnetic field generated by coil 112A in the Z direction are opposite to each other.

[0035] On the other hand, the coil 113D of the third inductor element 113 generates a magnetic field 113H in the -X direction. Therefore, when energized, the polarity of the magnetic pole at the end of coil 113D closer to the first inductor element 111 in the X direction is opposite to the polarity of the magnetic pole at the end of coil 111A closer to the third inductor element 113 in the Z direction. This relationship regarding the polarity of the magnetic poles can always be true. Also, when energized, the polarity of the magnetic pole at the end of coil 113D closer to the second inductor element 112 in the X direction is always opposite to the polarity of the magnetic pole at the end of coil 112A closer to the third inductor element 113 in the Z direction. This relationship regarding the polarity of the magnetic poles can also always be true. The third inductor element 113 is arranged so that the polarity of the magnetic poles of coil 113D is such that these relationships are true. The X direction referred to here corresponds to the direction connecting the center point of the first inductor element 111 and the center point of the second inductor element 112.

[0036] As shown in Figure 3D, the magnetic fields 111H and 112H generated by the first and second inductor elements 111 and 112 are suppressed from spreading toward the image sensor 9 as indicated by the dashed arrows 111HO and 112HO due to magnetic field induction by the third inductor element 113. Image sensors used in digital cameras and the like have a rectangular parallelepiped shape, and numerous signal lines, power lines, and circuits are distributed within their broad surface. According to this embodiment, the spreading of the magnetic fields 111H and 112H generated by the first and second inductor elements 111 and 112 can be suppressed, thereby preventing the magnetic fields 111H and 112H from reaching a wide area of ​​the image sensor 9.

[0037] Thus, according to this embodiment, it is possible to suppress the arrival of magnetic fields 111H and 112H to a wider range of image sensors 9.

[0038] In the above description, the third inductor element 113 was configured in a spiral shape using wiring 113A, 113B and via 113C, but it is not limited to this configuration. The third inductor element 113 may be an inductor component embedded in the printed circuit board 11. In this case as well, the same effects as described above can be obtained.

[0039] [Example 1] To illustrate the effects of the first embodiment described using Figure 3D, we will now describe Example 1, in which an electromagnetic field analysis was performed. For the electromagnetic field analysis, we used "Maxwell3D," an application software from ANSYS Electronics Desktop 2021 R2, a simulation tool from ANSYS Corporation.

[0040] In Example 1, 1608 size (long side 1.6 mm, short side 0.8 mm) chip inductor components were used as the first and second inductor elements 111 and 112, and these were mounted on the first surface 11a of the printed circuit board 11 with a gap of 0.1 mm. The number of turns of the coils 111A and 112A inside the first and second inductor elements 111 and 112 was set to 15 turns. The relative permeability of the magnetic materials 111B and 112B was set to 100. In the third inductor element 113, the length of the wiring 113A on the first surface 11a of the printed circuit board 11 and the wiring 113B of the inner layer was set to 1 mm, and the length of the via 113C was set to 0.25 mm, and these were connected in a spiral to form a 3-turn coil 113D. The thickness of the printed circuit board 11 was set to 1 mm, and an observation point for magnetic flux density was set on the second surface 11b on which the image sensor 9 was mounted. Six observation points were selected: observation points 9A, 9B, 9C, 9D, 9E, and 9F. Observation point 9A was defined as a point on the intersection of the plane perpendicular to the line segment connecting the center points of the first and second inductor elements 111 and 112 and the second surface 11b, i.e., a point symmetrical to the first and second inductor elements 111 and 112. Observation points 9B, 9C, 9D, 9E, and 9F were placed at intervals of 0.4 mm from observation point 9A in the +X direction toward the second inductor element 112. The frequency for observing the magnetic flux density was set to 1 MHz, assuming the switching operation of the power supply circuit 13.

[0041] Furthermore, as a comparative example corresponding to the prior art described in Patent Document 1, a configuration in which the third inductor element 113 is removed from the configuration of Example 1 and conductive pads 111F and 112F are directly connected by wiring was analyzed.

[0042] Figure 4 is a graph showing a comparison of magnetic flux densities at observation points 9A, 9B, 9C, 9D, 9E, and 9F in Example 1 and the Comparative Example. In Figure 4, the dashed line represents the Comparative Example, and the solid line represents Example 1.

[0043] As shown in Figure 4, in the comparative example, the magnetic flux density at observation point 9B, which is slightly offset from observation point 9A symmetrical to the first and second inductor elements 111 and 112, increased by 11% from the magnetic flux density at observation point 9A, reaching 0.99 μT. In the comparative example, as the distance from observation point 9B increased further, the magnetic flux density at observation points 9C, 9D, 9E, and 9F decreased sequentially due to the distance from the second inductor element 112.

[0044] On the other hand, in Example 1, due to the magnetic field induction effect of the third inductor element 113, the magnetic flux density was lower at all six observation points 9A, 9B, 9C, 9D, 9E, and 9F than in the comparative example. In Example 1, the increase in magnetic flux density at observation point 9B, which is slightly offset from observation point 9A which is symmetrical to the first and second inductor elements 111 and 112, from the magnetic flux density at observation point 9A was also 8%, and the increase in magnetic flux density was suppressed compared to the increase in the comparative example. As a result, in Example 1, the maximum value of the magnetic flux density reaching the image sensor 9 was reduced by 11%, from 0.99 μT in Comparative Example 1 to 0.88 μT.

[0045] [Second Embodiment] An electronic device according to a second embodiment of the present invention will be described with reference to Figures 5A to 6D. Components similar to those in the first embodiment will be denoted by the same reference numerals, and their descriptions will be omitted or simplified.

[0046] The basic configuration of the electronic device according to this embodiment is the same as that of the electronic device 1 according to the first embodiment shown in Figure 1. The electronic device according to this embodiment differs from the electronic device 1 according to the first embodiment in the configuration of the sensor module 6, which is an example of an electronic module.

[0047] First, a sensor module 6, which is an example of an electronic module according to this embodiment, will be described using Figures 5A and 5B. Figure 5 is a schematic diagram showing the sensor module 6 according to this embodiment in detail. Figure 5A is a plan view of the sensor module 6 as seen from the +Z direction. Figure 5B is a cross-sectional view showing a cross-section along the dashed line A200-A'200 in Figure 5A. Only the parts that differ from the first embodiment will be described.

[0048] In this embodiment, as shown in Figures 5A and 5B, in the inductor circuit 204 constituting the power supply circuit 13, a third inductor element 213 is used instead of the third inductor element 113 of the first embodiment. The sensor module 6 according to this embodiment differs from the sensor module 6 according to the first embodiment in that the third inductor element 213 is provided on the first surface 11a of the printed circuit board 11. The sensor module 6 according to this embodiment has an inductor circuit 204 instead of the inductor circuit 104 of the first embodiment. The inductor circuit 204 has a first inductor element 111, a second inductor element 112, and a third inductor element 213.

[0049] Next, the first inductor element 111, the second inductor element 112, and the third inductor element 213 that constitute the inductor circuit 104 will be described in detail with reference to Figures 6A to 6D. Figures 6A to 6D are schematic diagrams showing the area of ​​the inductor circuit 204 enclosed by dashed lines in Figures 5A and 5B, including the printed circuit board 11 and the image sensor 9. Figure 6A is a perspective view. Figure 6B is a plan view of Figure 6A viewed from the +Z direction. Figure 6C is a cross-sectional view showing a section along the dashed line A201-A'201 in Figure 6B. Figure 6D is a cross-sectional view showing a section along the dashed line A202-A'202 in Figure 6B.

[0050] As shown in Figures 6A to 6D, the first inductor element 111, the third inductor element 213, and the second inductor element 112 are arranged in this order in the +X direction on the first surface 11a of the printed circuit board 11. The first inductor element 111 and the second inductor element 112 are configured in the same way as in the first embodiment.

[0051] The third inductor element 213 is, for example, an inductor component and has a coil 213A, a magnetic material 213B, and electrodes 213C and 213D. The coil 213A is formed of a helical conductor. The coil 213A is embedded in the magnetic material 213B such that its winding axis is parallel to the X direction. Both ends of the coil 213A are connected to electrodes 213C and 213D, respectively. Electrodes 213C and 213D are one terminal and the other terminal of the third inductor element 213, respectively. Electrodes 213C and 213D are electrically connected to conductive pads 213E and 213F formed on the first surface 11a of the printed circuit board 11, respectively. The means of electrically connecting electrodes 213C and 213D to conductive pads 213E and 213F, respectively, are not particularly limited, but for example, solder joints.

[0052] The third inductor element 213 is positioned such that the winding axis of the coil 213A is parallel to the first surface 11a of the printed circuit board 11 and also parallel to the line segment connecting the center points of the first and second inductor elements 111 and 112. The first and second inductor elements 111 and 112 are configured such that the height of their respective centers from the first surface 11a is the same, that is, the direction connecting the center points of the first and second inductor elements 111 and 112 is parallel to the first surface 11a. The conductive pad 213F is connected to the conductive pad 111F by wiring 213G1 formed on the first surface 11a of the printed circuit board 11. The conductive pad 213E is connected to the conductive pad 112F by wiring 213G2 formed on the first surface 11a of the printed circuit board 11.

[0053] The third inductor element 213 is provided in the Z-direction within the range between the center point of the first inductor element 111 and the center point of the second inductor element 112 that is closer to the first surface 11a, and the first surface 11a itself. The first inductor element 111 and the second inductor element 112 may have the same structure, in which case the positions of their center points in the Z-direction are the same. The third inductor element 213, which is an inductor component, may be embedded in the printed circuit board 11.

[0054] Furthermore, the third inductor element 213 only needs to be provided within the range between the center point of the first inductor element 111 and the center point of the second inductor element 112, in the direction connecting the center point of the first inductor element 111 and the center point of the second inductor element 112. The first inductor element 111 and the second inductor element 112 may have the same structure, in which case the direction connecting the center point of the first inductor element 111 and the center point of the second inductor element 112 will be the X direction.

[0055] Furthermore, while the third inductor element 213 is positioned on the first surface 11a such that the winding axis of the coil 213A is parallel to the X direction, the positioning of the third inductor element 113 is not limited to this. The third inductor element 113 only needs to be positioned such that the winding axis of the coil 213A is parallel to the direction connecting the center point of the first inductor element 111 and the center point of the second inductor element 112.

[0056] In this way, a series connection circuit of the first inductor element 111, the second inductor element 112, and the third inductor element 213 is formed between wiring 107 and wiring 108.

[0057] As shown in Figures 6A and 6B, the currents 107J, 213J, and 108J generated in wirings 107 and 108 and inductor circuit 204 are indicated by arrows. These currents 107J, 213J, and 108J contain both DC and AC components. Current 107J is the current generated in wiring 107. Current 213J is the current generated in the third inductor element 213. Current 108J is the current generated in wiring 108. The directions of the three arrows for currents 107J, 213J, and 108J indicate that they are in the same phase relationship in the direction of the arrow at each frequency of the AC component.

[0058] Consider the case where currents 107J, 213J, and 108J are generated in the direction of the arrows with the same phase relationship shown in the diagram, at a frequency with an AC component. In this case, the first inductor element 111, the second inductor element 112, and the third inductor element 213 generate magnetic fields 111H, 112H, and 213H, respectively, in the direction of the arrows. That is, the first inductor element 111 generates a magnetic field 111H in the +Z direction. The second inductor element 112 generates a magnetic field 112H in the -Z direction, which is the opposite direction to the magnetic field 111H. The third inductor element 213 generates a magnetic field 113H in the -X direction.

[0059] Specifically, similar to the first embodiment, the coil 111A of the first inductor element 111 generates a magnetic field 111H in the +Z direction. The coil 112A of the second inductor element 112 generates a magnetic field 112H in the -Z direction, which is opposite to the direction of the magnetic field 111H. In this way, the first inductor element 111 and the second inductor element 112 are arranged such that the magnetic field generated by coil 111A and the magnetic field generated by coil 112A when energized are in opposite directions.

[0060] On the other hand, the coil 213A of the third inductor element 213 generates a magnetic field 213H in the -X direction. Therefore, when energized, the polarity of the magnetic pole at the end of coil 213A closer to the first inductor element 111 in the X direction is always the opposite polarity to the magnetic pole at the end of coil 111A closer to the third inductor element 213 in the Z direction. Also, when energized, the polarity of the magnetic pole at the end of coil 213A closer to the second inductor element 112 in the X direction is always the opposite polarity to the magnetic pole at the end of coil 112A closer to the third inductor element 213 in the Z direction. The third inductor element 213 is arranged so that the magnetic pole polarity of coil 213A is as described above. Note that the X direction here corresponds to the direction connecting the center point of the first inductor element 111 and the center point of the second inductor element 112.

[0061] As shown in Figure 6D, the magnetic fields 111H and 112H generated by the first and second inductor elements 111 and 112 are suppressed from spreading toward the image sensor 9 as indicated by the dashed arrows 111HO and 112HO due to magnetic field induction by the third inductor element 213.

[0062] Thus, according to this embodiment, the arrival of magnetic fields 111H and 112H to a wider range of the image sensor 9 can be suppressed. Furthermore, unlike the first embodiment, in this embodiment, the wiring area of ​​the inner layer of the printed circuit board 11 is not used to provide the third inductor element 213, so the inner layer wiring of the printed circuit board 11 can be used for other wiring. As a result, in this embodiment, a higher degree of freedom can be achieved in the design of the sensor module 6 compared to the first embodiment.

[0063] [Example 2] To illustrate the effects of the second embodiment described using Figure 6D, Example 2, in which electromagnetic field analysis was performed, will be described. In Example 2, electromagnetic field analysis was performed in the same manner as in Example 1. Below, only the differences from Example 1 and the comparative example will be described.

[0064] In Example 2, the first and second inductor elements 111 and 112, similar to those used in Example 1, were mounted on the first surface 11a of the printed circuit board 11 with a gap of 0.5 mm. In addition, a third inductor element 213, a 0603 size (long side 0.6 mm, short side 0.3 mm) chip inductor component, was mounted on the first surface 11a between the first and second inductor elements 111 and 112. The number of turns of the coil 213A inside the third inductor element 213 was set to 3 turns, and the relative permeability of the magnetic material 213B was set to 100. Similar to Example 1, the thickness of the printed circuit board 11 was set to 1 mm, and observation points for magnetic flux density were set on the second surface 11b on which the image sensor 9 was mounted. There were six observation points: 9A, 9B, 9C, 9D, 9E, and 9F. 9A was defined as a point on the intersection line between the plane perpendicular to the line segment connecting the center points of the first and second inductor elements 111 and 112 and the second surface 11b, i.e., a point symmetrical to the two first and second inductor elements 111 and 112. Observation points 9B, 9C, 9D, 9E, and 9F were placed at intervals of 0.4 mm from observation point 9A toward the second inductor element 112. The frequency for observing the magnetic flux density was set to 1 MHz, assuming the switching operation of the power supply circuit 13. Furthermore, a configuration corresponding to Patent Document 1, which is a prior art similar to Example 1, was used as a comparative example.

[0065] Figure 7 is a graph showing a comparison of magnetic flux densities at observation points 9A, 9B, 9C, 9D, 9E, and 9F in Example 2 and the Comparative Example. In Figure 7, the dashed line represents the Comparative Example, and the solid line represents Example 2.

[0066] As shown in Figure 7, in the comparative example, the magnetic flux density at observation point 9B, which is slightly offset from observation point 9A symmetrical to the first and second inductor elements 111 and 112, increased by 11% from the magnetic flux density at observation point 9A, reaching 0.99 μT. In the comparative example, as the distance from observation point 9B increased further, the magnetic flux density at observation points 9C, 9D, 9E, and 9F decreased sequentially due to the distance from the second inductor element 112.

[0067] On the other hand, in Example 2, due to the magnetic field induction effect of the third inductor element 213, the magnetic flux density was lower than in the comparative example at observation points 9A, 9B, and 9C, which have high magnetic flux densities. In Example 2, the increase in magnetic flux density at observation point 9B, which is offset from observation point 9A symmetrical to the first and second inductor elements 111 and 112, from the magnetic flux density at observation point 9A was also 9%, indicating that the increase in magnetic flux density was suppressed compared to the increase in the comparative example. As a result, in Example 2, the maximum value of the magnetic flux density reaching the image sensor 9 was reduced by 10%, from 0.99 μT to 0.89 μT.

[0068] [Other embodiments] The inductor circuits 104 and 204 according to the first and second embodiments described above can be modified in various ways. Modifications of the inductor circuits 104 and 204 will be explained using Figures 8A to 8F. Figures 8A to 8F are schematic diagrams for explaining modifications of the inductor circuits 104 and 204 according to the first and second embodiments. Figures 8A to 8F show variations in the connection configuration of the first inductor element 111, the second inductor element 112, and the third inductor elements 113 and 213 in the inductor circuits 104 and 204 according to the first and second embodiments. In Figures 8A to 8F, the same reference numerals are used for parts that are the same as those in the first and second embodiments.

[0069] Figure 8A shows the connection configuration of the first inductor element 111, the second inductor element 112, and the third inductor element 113 (third inductor element 213) as described in the first and second embodiments. In this case, the first inductor element 111, the third inductor element 113 (third inductor element 213), and the second inductor element 112 are connected in series in that order.

[0070] Figure 8B shows the case where the second inductor element 112 is wound in a different direction than shown in Figure 8A.

[0071] Figure 8C shows a case where the connection order of the first inductor element 111, the second inductor element 112, and the third inductor elements 113 and 213 is different from that of Figures 8A and 8B. In this case, the first inductor element 111, the second inductor element 112, and the third inductor element 113 (third inductor element 213) are connected in series in that order.

[0072] Figure 8D shows a series-parallel connection in which the first inductor element 111 and the second inductor element 112 are connected in series, and the third inductor element 113 (third inductor element 213) is connected in parallel to both ends of them.

[0073] Figure 8E shows a series-parallel connection in which the second inductor element 112 and the third inductor element 113 (third inductor element 213) are connected in parallel, and the first inductor element 111 is connected to one of the two connection points.

[0074] Figure 8F shows the case where the first inductor element 111, the second inductor element 112, and the third inductor element 113 (third inductor element 213) are connected in parallel.

[0075] As described above, in all connection configurations from Figure 8A to Figure 8F, the currents supplied to the three inductor elements are in phase, the generated magnetic fields are also in phase, and the third inductor element 113 always acts to induce the magnetic fields generated by the first and second inductor elements. As a result, the effects described in the first and second embodiments can be obtained regardless of which connection configuration is used.

[0076] Note that the connection configuration of the first inductor element, the second inductor element 112, and the third inductor elements 113 and 213 is not limited to the examples shown in Figures 8A to 8F, and the three inductor elements may be interchanged.

[0077] This embodiment includes the following configuration. (Composition 1) A printed circuit board having a first surface and a second surface facing each other, A first inductor element having a first coil and positioned on the first surface such that the direction of the winding axis of the first coil intersects the first surface, A second inductor element having a second coil, and positioned on the first surface such that the direction of the winding axis of the second coil intersects with the first surface, A third inductor element having a third coil, The first inductor element, the second inductor element, and the third inductor element are configured to always generate currents in the same phase when energized. The first inductor element and the second inductor element are arranged such that, when energized, the first magnetic field generated by the first coil in a first direction intersecting the first surface and the second magnetic field generated by the second coil in the first direction are in opposite directions to each other. The third inductor element is In the first direction, the center point of the first inductor element and the center point of the second inductor element are provided in a range from the center point closer to the first surface to the second surface, In a second direction connecting the center point of the first inductor element and the center point of the second inductor element, provided in the range between the center point of the first inductor element and the center point of the second inductor element, The winding axis of the third coil is positioned parallel to the second direction. When energized, the polarity of the magnetic pole at the end of the third coil closer to the first inductor element in the second direction becomes opposite to the polarity of the magnetic pole at the end of the first coil closer to the third inductor element in the first direction, When energized, the polarity of the magnetic pole at the end of the third coil closer to the second inductor element in the second direction is arranged to be opposite to the polarity of the magnetic pole at the end of the second coil closer to the third inductor element in the first direction. An electronic module characterized by the following features. (Configuration 2) The electronic module according to configuration 1, characterized in that the first inductor element, the second inductor element, and the third inductor element are electrically connected. (Composition 3) The electronic module according to configuration 2, characterized in that the first inductor element, the second inductor element, and the third inductor element are connected in series, in parallel, or in series-parallel. (Composition 4) The electronic module according to any one of configurations 1 to 3, characterized in that at least a portion of the third inductor element is provided inside the printed circuit board. (Composition 5) The printed circuit board has a plurality of wires and a plurality of vias formed on it. The electronic module according to any one of configurations 1 to 4, characterized in that the third coil is formed by the plurality of wirings and the plurality of vias. (Composition 6) The electronic module according to configuration 5, characterized in that the plurality of wirings include wiring formed on the first surface and wiring formed inside the printed circuit board. (Composition 7) The electronic module according to configuration 4, characterized in that the third inductor element is an inductor component embedded in the printed circuit board. (Composition 8) The electronic module according to any one of configurations 1 to 3, characterized in that the third inductor element is an inductor component arranged on the first surface. (Composition 9) An electronic module according to any one of configurations 1 to 8, characterized by having a semiconductor element arranged on the second surface. (Composition 10) The electronic module according to configuration 9, characterized in that the semiconductor element is an image sensor. (Composition 11) The electronic module according to configuration 9 or 10, characterized in that, in a plan view taken in the first direction, the first inductor element, the second inductor element, and the third inductor element are arranged to overlap with the semiconductor element. (Composition 12) The electronic module according to any one of configurations 1 to 11, characterized in that the first direction is a direction perpendicular to the first surface. (Composition 13) The electronic module according to any one of configurations 1 to 12, characterized in that the second direction is parallel to the first surface. (Composition 14) The first inductor element has a first magnetic material in which the first coil is embedded, The electronic module according to any one of configurations 1 to 13, characterized in that the second inductor element has a second magnetic material in which the second coil is embedded. (Composition 15) The electronic module according to any one of configurations 1 to 14, characterized in that it has circuit components arranged on the first surface and connected to the first inductor element, the second inductor element and the third inductor element. (Composition 16) The electronic module according to configuration 15, characterized in that the circuit component is a power control IC. (Composition 17) The electronic module according to any one of configurations 1 to 16, characterized in that the first inductor element, the third inductor element, and the second inductor element are arranged in this order in the second direction. (Composition 18) The casing and The electronic module described in any one of configurations 1 to 17, which is arranged inside the aforementioned housing. An electronic device characterized by having the following features. [Explanation of Symbols]

[0078] 1. Digital camera 2. Camera body 3. Lens Unit 4. Cabinet 5. Processing Module 6. Sensor Module 7. Cable 8...Battery 9. Image sensor 10, 11, ... Printed circuit board 12, 14... Electronic components 13...Power circuit 101...Input terminal 102...Output terminal 103... Power control IC 104, 204... Inductor circuits 105... Capacitor components 106, 107, 108, 113A, 113B, 213G... Wiring 109, 110... Ground wiring 111...First inductor element 112...Second inductor element 113, 213...Third inductor element 111A, 112A, 103D, 213A... Coils 111B, 112B, 213B...Magnetic material 111C, 111D, 112C, 112D, 213C, 213D... Electrode 111E, 111F, 112E, 112F, 213E, 213F... Conductive pads 113C... Beer

Claims

1. A printed circuit board having a first surface and a second surface facing each other, A first inductor element having a first coil, and arranged on the first surface such that the direction of the winding axis of the first coil intersects the first surface, A second inductor element having a second coil, and positioned on the first surface such that the direction of the winding axis of the second coil intersects with the first surface, It has a third inductor element having a third coil, The first inductor element, the second inductor element, and the third inductor element are configured to always generate currents in the same phase when energized. The first inductor element and the second inductor element are arranged such that, when energized, the first magnetic field generated by the first coil in a first direction intersecting the first surface and the second magnetic field generated by the second coil in the first direction are in opposite directions to each other. The third inductor element is, In the first direction, the center point of the first inductor element and the center point of the second inductor element are provided in a range between the center point closer to the first surface and the second surface, In a second direction connecting the center point of the first inductor element and the center point of the second inductor element, provided in the range between the center point of the first inductor element and the center point of the second inductor element, The winding axis of the third coil is positioned so that its direction is parallel to the second direction. When energized, the polarity of the magnetic pole at the end of the third coil closer to the first inductor element in the second direction becomes opposite to the polarity of the magnetic pole at the end of the first coil closer to the third inductor element in the first direction, When energized, the polarity of the magnetic pole at the end of the third coil closer to the second inductor element in the second direction is arranged to be opposite to the polarity of the magnetic pole at the end of the second coil closer to the third inductor element in the first direction. An electronic module characterized by the following features.

2. The electronic module according to claim 1, characterized in that the first inductor element, the second inductor element, and the third inductor element are electrically connected.

3. The electronic module according to claim 2, characterized in that the first inductor element, the second inductor element, and the third inductor element are connected in series, in parallel, or in series-parallel.

4. The electronic module according to claim 1 or 2, characterized in that at least a portion of the third inductor element is provided inside the printed circuit board.

5. The printed circuit board has a plurality of wires and a plurality of vias formed on it. The electronic module according to claim 1 or 2, characterized in that the third coil is formed by the plurality of wirings and the plurality of vias.

6. The electronic module according to claim 5, characterized in that the plurality of wirings include wiring formed on the first surface and wiring formed inside the printed circuit board.

7. The electronic module according to claim 4, characterized in that the third inductor element is an inductor component embedded in the printed circuit board.

8. The electronic module according to claim 1 or 2, characterized in that the third inductor element is an inductor component arranged on the first surface.

9. The electronic module according to claim 1 or 2, characterized by having semiconductor elements arranged on the second surface.

10. The electronic module according to claim 9, characterized in that the semiconductor element is an image sensor.

11. The electronic module according to claim 9, characterized in that, in a plan view taken in the first direction, the first inductor element, the second inductor element, and the third inductor element are arranged to overlap with the semiconductor element.

12. The electronic module according to claim 1 or 2, characterized in that the first direction is a direction perpendicular to the first surface.

13. The electronic module according to claim 1 or 2, characterized in that the second direction is parallel to the first surface.

14. The first inductor element has a first magnetic material in which the first coil is embedded, The electronic module according to claim 1 or 2, characterized in that the second inductor element has a second magnetic material in which the second coil is embedded.

15. The electronic module according to claim 1 or 2, characterized in that it has circuit components arranged on the first surface and connected to the first inductor element, the second inductor element and the third inductor element.

16. The electronic module according to claim 15, characterized in that the circuit component is a power control IC.

17. The electronic module according to claim 1 or 2, characterized in that the first inductor element, the third inductor element, and the second inductor element are arranged in this order in the second direction.

18. The casing and The electronic module according to claim 1 or 2, disposed inside the housing An electronic device characterized by having the following features.

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